Bio


Dr. Tran is a fellowship-trained vascular surgeon in the Vascular and Endovascular Surgery Division at Stanford Health Care. He is also a clinical assistant professor in the Department of Surgery, Division of Vascular Surgery at Stanford University School of Medicine.

Dr. Tran’s clinical expertise includes the entire spectrum of vascular surgery, including minimally invasive strategies for aortic aneurysm repair and multiple methods of managing peripheral vascular disease. He also specializes in treating cerebrovascular disease (problems with blood flow in the brain) using carotid angioplasty and stenting, transcarotid artery revascularization, and conventional carotid surgery. In addition, Dr. Tran offers comprehensive dialysis access management and treats venous reflux (when leg veins fail to return blood to the heart).

Dr. Tran has a special interest in minimally invasive techniques for repairing complex aortic conditions using custom stents placed inside blood vessels (endografts). He has expertise in designing, fabricating, and implanting physician-modified endografts tailor-made to each patient’s unique aortic anatomy. This technique expands the ability to offer minimally invasive repair to more patients.

Dr. Tran’s research efforts focus on utilizing novel computational approaches to better understand and optimize blood flow patterns after complex aortic repair. This work has helped improve the understanding of how different types of aneurysm repair perform long term. Dr. Tran hopes to use these research findings to improve clinical outcomes for patients with aortic aneurysmal disease.

Dr. Tran has published his work in numerous prestigious peer-reviewed journals, including the Journal of Vascular Surgery, JAMA Surgery, and the European Journal of Vascular and Endovascular Surgery. He has presented at the podium at numerous national and international conferences.

Dr. Tran has received multiple research awards, including the Vascular and Endovascular Surgery Society’s Medtronic Resident Research Award and Best Resident Presentation at the Swiss Society for Vascular Diseases. In addition, he received the Young Researcher Prize at the European Symposium on Vascular Biomaterials for his research related to complex aortic repair hemodynamics (blood flow). Dr. Tran also coauthored a chapter in the book Complications in Endovascular Surgery.

Clinical Focus


  • Vascular Surgery

Academic Appointments


Honors & Awards


  • Best Resident Presentation, 21st Meeting of the Swiss Societies for Vascular Diseases
  • First place, Medical Student Surgical Skills Competition (Society for Vascular Surgery Vascular Annual Meeting)
  • Medtronic Resident Research Award, Vascular and Endovascular Surgery Society
  • Outstanding Abstract Presentation Award, Charing Cross Symposium
  • Second Place, Medical Student Paper Presentation (Introduction to Academic Vascular Surgery (IAVS))
  • Second Place, Resident Skills Competition (Pacific Northwest Endovascular Conference)
  • Veith LEAD Award (Best Resident Presentation), Vascular Techniques & Technology Thinktank (VAST3) Meeting
  • Young Researcher Prize, European Symposium on Vascular Biomaterials

Professional Education


  • Residency: Stanford University Vascular Surgery Residency/Fellowship (2023) CA
  • Medical Education: Stanford University School of Medicine (2016) CA
  • BS, University of Virginia, Biomedical Engineering (2011)

2023-24 Courses


All Publications


  • A fenestrated, double-barrel technique for proximal reintervention after open or endovascular abdominal aortic aneurysm repair. Journal of vascular surgery cases and innovative techniques Stern, J. R., Tran, K., Dossabhoy, S. S., Sorondo, S. M., Lee, J. T. 2023; 9 (1): 101091

    Abstract

    Proximal endovascular reintervention after prior endovascular aortic repair (EVAR) or open abdominal aortic aneurysm repair (OR) can be challenging due to the short distance to the visceral branches. We present a novel solution to allow the use of the commercially available ZFEN device using a double-barrel, kissing-limb technique.Patients who underwent fenestrated repair for proximal failure after EVAR or OR were identified. The ZFEN device is deployed above the prior graft flow divider. Once the visceral branches are secured, kissing limbs are used to connect with the prior graft limbs. The distal diameter of the standard ZFEN is 24 mm, accommodating two 20 mm components according to the formula 2πDLIMB = πDZFEN + 2DZFEN.Of 235 patients who underwent repair using ZFEN from 2012 to 2021 at a single institution, 28 were treated for proximal failure of prior repairs, with 13 treated using the double-barrel technique (8 EVAR, 5 OR). The distance from the flow divider to the lowest renal artery was 67 ± 24.4 mm (range, 39-128 mm), and the distance to the superior mesenteric artery (SMA) was 87 ± 30.5 mm (range, 60-164 mm). Technical success was 100%. Seven patients had standard ZFEN builds (2 renal small fenestrations, SMA large fen/scallop). The minimum distance to the lowest renal artery and SMA to accommodate a standard ZFEN build was 56 and 60 mm, respectively. Four patients required adjunctive snorkel grafts and two required laser fenestrations. Two patients had gutter leaks at 1 month that self-resolved; one patient developed a late type 1a endoleak. Freedom from reintervention was 90%, 72%, and 48% at 1, 2, and 3 years, respectively.This double-barrel technique allows for distal seal of commercial ZFEN devices into prior open or endovascular repairs with good technical success. Long-term outcomes remain to be quantified.

    View details for DOI 10.1016/j.jvscit.2022.101091

    View details for PubMedID 36747609

    View details for PubMedCentralID PMC9898739

  • Validity of the Global Vascular Guidelines in Predicting Outcomes Based on First-Time Revascularization Strategy. Annals of vascular surgery Lou, V., Dossabhoy, S. S., Tran, K., Yawary, F., Ross, E. G., Stern, J. R., Dalman, R. L., Chandra, V. 2023

    Abstract

    The Global Vascular Guidelines (GVG) recommend selecting an endovascular vs open-surgical approach to revascularization for chronic limb-threatening ischemia (CLTI), based on the Global Limb Anatomic Staging System (GLASS) and Wound, Ischemia, and Foot Infection (WIfI) classification systems. We assessed the utility of GVG-recommended strategies in predicting clinical outcomes.We conducted a single-center, retrospective review of first-time lower-extremity revascularizations within a comprehensive limb-preservation program from 2010-2018. Procedures were stratified by 1) treatment concordance with GVG-recommended strategy (concordant vs non-concordant groups), 2) GLASS stages I-III, and 3) endovascular vs open strategies. The primary outcome was 5-year freedom from major adverse limb events (FF-MALE), defined as freedom from reintervention or major amputation, and secondary outcomes included 5-year overall survival, freedom from major amputation, freedom from reintervention, and immediate technical failure during initial revascularization. Kaplan-Meier (KM) survival analysis and multivariate analysis with Cox proportional hazard models were performed on the primary and secondary outcomes, RESULTS: Of 281 first-time revascularizations for CLTI, 251 (89.3%) were endovascular and 186 (66.2%) were in the concordant group, with a mean clinical follow-up of 3.02±2.40 years. Within the concordant group alone, 167 (89.8%) of revascularizations were endovascular. The concordant group had a higher rate of chronic kidney disease (60.8% vs 45.3%, P=.02), WIfI foot infection grade (0.81±1.1 vs 0.56±0.80, P=.03), and WIfI stage (3.1±0.79 vs 2.8±1.2, P<.01) compared to the non-concordant group. After both KM and multivariate analyses, there were no significant differences in 5-year FF-MALE or overall survival between concordant and non-concordant groups. There was higher freedom from major amputation in the non-concordant group on KM analysis (83.9% vs 74.2%, P=.025), though this difference was non-significant on multivariate analysis (HR 0.49, 95% CI 0.21-1.15, P=.10). The open group had lower MALE compared to the endovascular group (HR 0.39, 95% CI 0.17-0.91, P=.029) attributed to a lower reintervention rate in the open group (HR 0.31, 95% CI 0.11-0.87, P=.026). GLASS stage was not associated with significant differences in outcomes, but the severity of GLASS stage was associated with immediate technical failure (2.1% in stage 1, 6.4% in stage 2, and 11.7% in stage 3, P=.01).In this study, CLTI treatment outcomes did not differ significantly based on whether treatment was received in concordance with GVG-recommended strategy. There was no difference in overall survival between the endovascular and open groups, though there was a higher reintervention rate in the endovascular group. The GVG guidelines are an important resource to help guide the management of CLTI patients. However, in this study, both concordance with GVG guidelines and GLASS staging were found to be indeterminate in differentiating outcomes between complex CLTI patients treated primarily with an endovascular-first approach. The revascularization approach for a CLTI patient is a nuanced decision that must take into account patient anatomy and clinical status, as well as physician skill and experience and institutional resources.

    View details for DOI 10.1016/j.avsg.2023.02.001

    View details for PubMedID 36828135

  • Most Privately Insured Patients Do Not Receive Federally Recommended Abdominal Aortic Aneurysm Screening. Journal of vascular surgery Ho, V. T., Tran, K., George, E. L., Asch, S. M., Chen, J. H., Dalman, R. L., Lee, J. T. 2023

    Abstract

    Since 2005, the United States Preventative Services Task Force (USPSTF) has recommended abdominal aortic aneurysm (AAA) ultrasound screening for 65- to 75-year-old male ever-smokers. Integrated health systems such as Kaiser Permanente and the Veterans Affairs (VA) healthcare system report 74-79% adherence, but compliance rates in the private sector are unknown.The IBM Marketscan® Commercial and Medicare Supplemental databases (2006 -2017) were queried for male ever-smokers continuously enrolled from age 65 to 75. Exclusion criteria were previous history of abdominal aortic aneurysm, connective tissue disorder, and aortic surgery. Patients with abdominal computed tomographic or magnetic resonance imaging from ages 65 to 75 were also excluded. Screening was defined as a complete abdominal, retroperitoneal, or aortic ultrasound. A logistic mixed-effects model utilizing state as a random intercept was used to identify patient characteristics associated with screening.Of 35,154 eligible patients, 13,612 (38.7%, Table 1) underwent screening. Compliance varied by state, ranging from 24.4% in Minnesota to 51.6% in Montana (p <0.05, Figure 1). Screening activity increased yearly, with 0.7% of screening activity occurring in 2008 versus 22.2% in 2016 (p <0.05, Figure 2). In a logistic mixed-effects model adjusting for state as a random intercept, history of hypertension (OR 1.07, 95% CI [1.03 - 1.13]), coronary artery disease (OR 1.17, 95% CI [1.10, 1.22]), congestive heart failure (OR 1.14, 95% CI [1.01 - 1.22]), diabetes (OR 1.1, 95% CI [1.06 - 1.16]) and chronic kidney disease (OR 1.4 95% CI [1.24 - 1.53]) were associated with screening. Living outside of a census-designated metropolitan area was negatively associated with screening (OR 0.92, 95% CI [0.87 - 0.97], Table 2).In a private claims database representing 250 million claimants, 38.7% of eligible patients received UPSTF-recommended AAA screening. Compliance was nearly half that of integrated health systems and was significantly lower for patients living outside of metropolitan areas. Efforts to improve early detection of AAA should include targeting non-metropolitan areas and modifying Medicare reimbursement and incentivization strategies to improve guideline adherence.

    View details for DOI 10.1016/j.jvs.2023.01.202

    View details for PubMedID 36781115

  • Changing gears: a guide to cruising back to the operating room. Vascular Specialist Vascular Specialist Tran, K. 2023
  • Patient-Specific Computational Flow Simulation Reveals Significant Differences in Paravisceral Aortic Hemodynamics Between Fenestrated and Branched Endovascular Aneurysm Repair Tran, K., DeGlise, S., Deslarzes-Dubuis, C., Kaladji, A., Yang, W., Marsden, A., Lee, J. MOSBY-ELSEVIER. 2022: E83-E84
  • Large Fenestrations Versus Scallops for the SMA During Fenestrated EVAR: Does it Matter? Annals of vascular surgery Sorondo, S. M., Ss, D., K, T., Vt, H., Jr, S., J, L. 2022

    Abstract

    FEVAR is an established customized treatment for aortic aneurysms with three current commercially available configurations for the superior mesenteric artery (SMA) - a single-wide scallop, large fenestration, or small fenestration, with the scallop or large fenestration most utilized. Outcomes comparing SMA single-wide scallops to large fenestrations with the ZFEN device are scarce. As large fenestrations have the benefit of extending the proximal seal zone compared to scalloped configurations, we sought to determine the differences in seal zone and sac regression outcomes between the two SMA configurations.We retrospectively reviewed our prospectively maintained complex EVAR database and included all patients treated with the Cook ZFEN device with an SMA scallop or large fenestration configuration at its most proximal build. All first post-operative CT scans (1-30 days) were analyzed on TeraRecon to determine precise proximal seal zone lengths, and standard follow-up anatomic and clinical metrics were tabulated.A total of 234 consecutive ZFEN patients from 2012-2021 were reviewed, and 137 had either a scallop or large fenestration for the SMA as the proximal-most configuration (72 scallops and 65 large fenestrations) with imaging available for analysis. Mean follow-up was 35 months. Mean proximal seal zone length was 19.5±7.9 mm for scallop vs 41.7±14.4 mm for large fenestration groups (P<.001). There was no difference in sac regression between scallop and large fenestration at one year (10.1±10.9 mm vs 11.0±12.1, P = 0.63). Overall, 30-day mortality (1.3% vs 2.5%, P=.51) and all-cause three-year mortality (72.5% vs 81.7%, P=.77) were not significantly different. Reinterventions within 30 days were primarily secondary to renal artery branch occlusions, with only one patient in the scallop group requiring reintervention for an SMA branch occlusion.Despite attaining longer proximal seal lengths, large SMA fenestrations were not associated with a difference in sac regression compared to scalloped SMA configurations at one-year follow up. There were no significant differences in reinterventions or overall long-term survival between the two SMA strategies.

    View details for DOI 10.1016/j.avsg.2022.07.013

    View details for PubMedID 36058451

  • Female sex is independently associated with reduced inpatient mortality after endovascular repair of blunt thoracic aortic injury. Journal of vascular surgery Ho, V. T., Sorondo, S., Forrester, J. D., George, E. L., Tran, K., Lee, J. T., Garcia-Toca, M., Stern, J. R. 2022

    Abstract

    Female sex has been associated with decreased mortality following blunt trauma, but whether sex influences outcomes of thoracic endovascular aortic repair (TEVAR) for traumatic blunt thoracic aortic injury (BTAI) is unknown.In this retrospective study of a prospectively maintained database, the Vascular Quality Initiative (VQI) registry was queried from 2013-2020 for patients undergoing TEVAR for BTAI. Univariate Student's t-tests and chi-squared tests were performed, followed by multivariate logistic regression for variables associated with inpatient mortality.211 (26.2%) of 806 patients were female. Female patients were older (47.9 vs. 41.8 years, p<0.0001) and less likely to smoke (38.3% vs. 48.2%, p=0.044). Most patients presented with grade III BTAI (54.5% female, 53.6% male,), followed by grade IV (19.0% female, 19.5% male). Mean Injury Severity Scores (30.9 + 20.3 female, 30.5 + 18.8 male) and regional Abbreviated Injury Score did not vary by sex. Postoperatively, female patients were less likely to die as inpatients (3.8% vs 7.9% , p=0.042) and to be discharged home (41.4% vs. 52.2%, p=0.008). On multivariate logistic regression, female sex (OR 0.05, p=0.002) was associated with reduced inpatient mortality. Advanced age (OR 1.06, p< 0.001), postoperative transfusion (OR 1.05, p=0.043), increased Injury Severity Score (OR 1.03, p=0.039), postoperative stroke (OR 9.09, p= 0.016), postoperative myocardial infarction (OR 9.9, p=0.017), and left subclavian coverage (OR 2.7, p= 0.029) were associated with inpatient death.Female sex is associated with lower odds of inpatient mortality following TEVAR for BTAI, independent of age, injury severity, BTAI grade, and postoperative complications. Further study of the influence of sex on post-discharge outcomes is needed.

    View details for DOI 10.1016/j.jvs.2022.07.178

    View details for PubMedID 35944732

  • Anatomic factors contributing to external iliac artery endofibrosis in high performance athletes. Annals of vascular surgery Fisher, A. T., Tran, K., Dossabhoy, S. S., Sorondo, S., Fereydooni, A., Lee, J. T. 2022

    Abstract

    External iliac artery endofibrosis (EIAE) classically presents in cyclists with intimal thickening of the affected arteries. We investigated possible anatomical predisposing factors including psoas muscle hypertrophy, arterial tortuosity, inguinal ligament compression, and arterial kinking via case-control comparison of symptomatic and contralateral limbs.All patients with unilateral EIAE treated surgically at our institution were reviewed. Each patient's symptomatic side was compared with their contralateral side using paired t-tests. Psoas hypertrophy was quantified by transverse cross-sectional area (CSA) at L4, L5, and S1 vertebral levels, and inguinal ligament compression was measured as anterior-posterior distance between inguinal ligament and underlying bone. Tortuosity index for diseased segments and arterial kinking were measured on TeraRecon.Of 33 patients operated on for EIAE from 2004-2021, 27 with available imaging presented with unilateral disease, more commonly left-sided (63%). Most (96%) had external iliac involvement and 26% had ≥2 segments affected: 19% common iliac artery, 15% common femoral artery. The symptomatic limb had greater mean L5 psoas CSA (1450 mm2 vs. 1396 mm2, mean difference 54 mm2, P=0.039). There were no significant differences in L4 or S1 psoas hypertrophy, tortuosity, inguinal ligament compression, or arterial kinking. 63% underwent patch angioplasty and 85% underwent additional inguinal ligament release. 84% reported postoperative satisfaction, which was associated with greater difference in psoas hypertrophy at L4 (p=0.022).Psoas muscle hypertrophy is most pronounced at L5 and is associated with symptomatic EIAE. Preferential hypertrophy of the affected side correlates with improved outcomes, suggesting psoas muscle hypertrophy as a marker of disease severity.

    View details for DOI 10.1016/j.avsg.2022.05.011

    View details for PubMedID 35654289

  • Fenestrated Aortic Aneurysm Repair in Patients Treated Inside Versus Outside of Instructions for Use. Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists Stern, J. R., Deslarzes-Dubuis, C., Tran, K., Lee, J. T. 1800: 15266028211068762

    Abstract

    OBJECTIVES: The aim of this study was to compare outcomes of patients treated with the Cook Zenith Fenestrated (ZFEN) device for juxtarenal aortic aneurysms inside versus outside the IFU.METHODS: We retrospectively reviewed our institutional ZFEN database for cases performed between 2012 and 2018, with analysis performed in 2020 in order to report midterm outcomes. The cohort was stratified based on treatment inside (IFU group) and outside (non-IFU group) the IFU for criteria involving the proximal neck: neck length 4 to 14 mm, neck diameter 19 to 31 mm, and neck angulation ≤45°. Patients with thoracoabdominal aneurysms or concurrent chimney grafting were excluded. The primary outcomes in question were mortality, type 1a endoleak, and reintervention. Univariate and multivariate analyses were performed to determine associations between adherence to IFU criteria and outcomes.RESULTS: We identified 100 consecutive patients (19% female, mean age 73.6 years) for inclusion in this analysis. Mean follow-up was 21.6 months. Fifty-four patients (54%) were treated outside the IFU because of inadequate neck length (n=48), enlarged neck diameter (n=10), and/or excessive angulation (n=16). Eighteen patients were outside IFU for two criteria, and one patient was outside IFU for all three. Non-IFU patients were exposed to higher radiation doses (3652 vs 5445 mGy, p=0.008) and contrast volume (76 vs 95 mL, p=0.004). No difference was noted between IFU and non-IFU groups for 30-day mortality (0% vs 3.7%, p=0.18), or type 1a endoleak (0% vs 1.9%, p=0.41). Reintervention was also similar between cohorts (13% vs 27.8%, p=0.13). Being outside IFU for neck diameter or length was each borderline significant for higher reintervention on univariate analysis (p=0.05), but this was not significant on multivariate Cox proportional hazard modeling (HR 1.82 [0.53-6.25]; 2.03 [0.68-7.89]), respectively. No individual IFU deviations were associated with the primary outcomes on multivariate analysis, nor being outside IFU for multiple criteria.CONCLUSIONS: Patients with juxtarenal aortic aneurysms may be treated with the ZFEN device with moderate deviations from the IFU. While no differences were seen in mortality or proximal endoleak, larger studies are needed to examine the potential association between IFU nonadherence and reinterventions and close follow-up is warranted for all patients undergoing such repair.

    View details for DOI 10.1177/15266028211068762

    View details for PubMedID 34994244

  • Patient-specific changes in aortic hemodynamics is associated with thrombotic risk after fenestrated endovascular aneurysm repair with large diameter endografts. JVS-vascular science Tran, K., Feliciano, K. B., Yang, W., Schwarz, E. L., Marsden, A. L., Dalman, R. L., Lee, J. T. 2022; 3: 219-231

    Abstract

    Background: The durability of fenestrated endovascular aneurysm repair (fEVAR) has been threatened by thrombotic complications. In the present study, we used patient-specific computational fluid dynamic (CFD) simulation to investigate the effect of the endograft diameter on hemodynamics after fEVAR and explore the hypothesis that diameter-dependent alterations in aortic hemodynamics can predict for thrombotic events.Methods: A single-institutional retrospective study was performed of patients who had undergone fEVAR for juxtarenal aortic aneurysms. The patients were stratified into large diameter (34-36mm) and small diameter (24-26mm) endograft groups. Patient-specific CFD simulations were performed using three-dimensional paravisceral aortic models created from computed tomographic images with allometrically scaled boundary conditions. Aortic time-averaged wall shear stress (TAWSS) and residence time (RT) were computed and correlated with future thrombotic complications (eg, renal stent occlusion, development of significant intraluminal graft thrombus).Results: A total of 36 patients (14 with a small endograft and 22 with a large endograft) were included in the present study. The patients treated with large endografts had experienced a higher incidence of thrombotic complications compared with small endografts (45.5% vs 7.1%; P= .016). Large endografts were associated with a lower postoperative aortic TAWSS (1.45± 0.76dynes/cm2 vs 3.16± 1.24dynes/cm2; P< .001) and longer aortic RT (0.78± 0.30second vs 0.34± 0.08second; P< .001). In the large endograft group, a reduction >0.39dynes/cm2 in aortic TAWSS demonstrated discriminatory power for thrombotic complications (area under the receiver operating characteristic curve, 0.77). An increased aortic RT of ≥0.05second had similar accuracy for predicting thrombotic complications (area under the receiver operating characteristic curve, 0.78). The odds of thrombotic complications were significantly higher if patients had met the hemodynamic threshold changes in aortic TAWSS (odds ratio, 7.0; 95% confidence interval, 1.1-45.9) and RT (odds ratio, 8.0; 95% confidence interval, 1.13-56.8).Conclusions: Patient-specific CFD simulation of fEVAR in juxtarenal aortic aneurysms demonstrated significant endograft diameter-dependent differences in aortic hemodynamics. A postoperative reduction in TAWSS and an increased RT correlated with future thrombotic events after large-diameter endograft implantation. Patient-specific simulation of hemodynamics provides a novel method for thrombotic risk stratification after fEVAR.

    View details for DOI 10.1016/j.jvssci.2022.04.002

    View details for PubMedID 35647564

  • Fenestrated endovascular repair with large device diameters (34- to 36-mm) is associated with type 1 and 3 endoleak and reintervention. Annals of vascular surgery Deslarzes-Dubuis, C., Stern, J. R., Tran, K., Colvard, B., Lee, J. T. 2021

    Abstract

    OBJECTIVES: Patients with abdominal aortic aneurysms undergoing EVAR with larger device diameters (34- to 36-mm) have worse outcomes due to proximal fixation failure and need for reintervention. We examine outcomes relating to standard fenestrated repair (FEVAR) with larger device diameters, and investigate whether a similar relationship exists.MATERIAL AND METHODS: Retrospective review of a prospectively maintained, single institution database of patients treated with the Cook ZFEN device between 2012-2017. Outcomes were stratified by device diameter into normal-diameter (ND,≤ 32 mm) and large-diameter (LD,34-36 mm). Primary endpoints were need for reintervention and composite type I/III endoleak.RESULTS: 100 consecutive patients treated were identified for inclusion. Overall mean age was 73.6 years and mean aortic diameter was 59.1 mm. Mean follow-up was 22 months. A total of 26 (26%) patients were treated with LD devices. Number of target vessels per patient was 2.8 in both groups. Infrarenal neck length and diameter were significantly different in the LD and ND patients, respectively (2.6 mm vs 4.7 mm (P<.01) and 30.1 mm vs 23.4 mm (P<.01)). Percent graft oversizing was lower in the LD cohort (19% vs 24%; P=.006). No difference was seen in overall mortality at 30-days (0% vs 2%; P=.4) or at latest follow up (6% vs 14%; P=.6). Reinterventions were not significantly different at 30 days, but were significantly higher over the follow-up period in the LD cohort (46.2 vs. 17.6%; P=.002). LD diameter was associated with reintervention on univariate (HR 1.19, 95% CI 1.04-1.37), but not multivariate analysis. The composite endpoint of type I/III endoleak was higher in the LD cohort (15.4% vs. 2.7%; P=.004).CONCLUSION: FEVAR requiring 34- or 36-mm device diameters is associated with an increased risk of composite type I/III endoleak and reintervention. Patients undergoing fenestrated repair requiring LD devices should be closely monitored, with consideration for proximal or open repair.

    View details for DOI 10.1016/j.avsg.2021.07.055

    View details for PubMedID 34656711

  • Reintervention Does Not Increase Long-term Mortality After Fenestrated Endovascular Aneurysm Repair Dossabhoy, S. S., Sorondo, S. M., Tran, K., Stern, J. R., Dalman, R. L., Lee, J. T. MOSBY-ELSEVIER. 2021: E399-E400
  • Validity of the Global Vascular Guidelines in Predicting Outcomes in a Comprehensive Wound Care Program Lou, V., Tran, K., Dossabhoy, S. S., Yawary, F., Ross, E. G., Stern, J. R., Lee, J. T., Harris, E., Dalman, R. L., Chandra, V. MOSBY-ELSEVIER. 2021: E405-E406
  • Intensive Blood Pressure Control and Diabetes Mellitus-Related Limb Events in Patients With Type 2 Diabetes Mellitus: Reanalysis of ACCORD. Journal of the American Heart Association Tran, K., Stedman, M., Chang, T. I. 2021: e021407

    View details for DOI 10.1161/JAHA.121.021407

    View details for PubMedID 34320842

  • Unique Complications and Failure Modes of Iliac Branch Devices. Annals of vascular surgery Stern, J. R., Tran, K., Li, M., Lee, J. T. 2021

    Abstract

    OBJECTIVES: Iliac branch devices (IBDs) are modular, bifurcated endografts designed to preserve hypogastric flow during endovascular aortoiliac aneurysm repair. We report our single center outcomes, and describe the unique complications of these devices: inability to cannulate the hypogastric artery (technical failure), occlusion of the internal branch, and type III endoleak from separation of components between the main body and IBD.METHODS: A prospectively maintained institutional database of patients undergoing IBD implantation between 2014 and 2019 was reviewed. Technical and clinical outcomes were evaluated. We then identified patients having one of the IBD-specific complications and patient, anatomic, and procedural data were analyzed to identify factors associated with these failures.RESULTS: 64 IBDs were placed in 59 patients during the study period. Mean age was 71.2±8.6, and 92% were male. 74.6% of patients had a current or prior abdominal aortic aneurysm, and 9.4% had a hypogastric aneurysm. Technical success was achieved in 60/64 cases (93.8%); prior EVAR was associated with technical failure (p=0.04). There were 5 instances of component separation between the main body and the IBD: 3 occurred intraoperatively and were repaired with additional bridging components, and 2 occurred on late follow-up and required reintervention. Increased tortuosity index of both aortoiliac (1.7±0.4 vs. 1.3±02, p=0.04) and iliac-specific (3.9±2.4 vs. 1.9±0.9, p=0.03) segments were significantly associated with component separation, as was the use of larger internal iliac components (13.9±2.4 vs. 11.1±2.3 mm, p=0.04). Internal branch occlusions occurred in 4 patients (6.7%). Two were successfully reopened with endovascular procedures, with two being asymptomatic. No specific factors were found to be predictive of branch occlusion.CONCLUSIONS: IBD-specific complications occur rarely. History of prior EVAR is associated with technical failure, while increased aortic and iliac tortuosity are predictive of component separation and type III endoleak. Severe tortuosity should be carefully considered when planning for IBD.

    View details for DOI 10.1016/j.avsg.2021.03.008

    View details for PubMedID 33836229

  • Bicycle Exercise Ankle-Brachial Index Recovery Time as a Novel Metric for Evaluating the Hemodynamic Significance of External Iliac Endofibrosis in Competitive Cyclists Tran, K., Dossabhoy, S., Sorondo, S., Lee, J. T. MOSBY-ELSEVIER. 2021: E50
  • Patient-specific computational flow modelling for assessing hemodynamic changes following fenestrated endovascular aneurysm repair. JVS-vascular science Tran, K., Yang, W., Marsden, A., Lee, J. T., Stanford, C. 2021; 2: 53-69

    Abstract

    Objective: This study aimed to develop an accessible patient-specific computational flow modelling pipeline for evaluating the hemodynamic performance of fenestrated endovascular aneurysm repair (fEVAR), with the hypothesis that computational flow modelling can detect aortic branch hemodynamic changes associated with fEVAR graft implantation.Methods: Patients who underwent fEVAR for juxtarenal aortic aneurysms with the Cook ZFEN were retrospectively selected. Using open-source SimVascular software, preoperative and postoperative visceral aortic anatomy was manually segmented from computed tomography angiograms. Three-dimensional geometric models were then discretized into tetrahedral finite element meshes. Patient-specific pulsatile in-flow conditions were derived from known supraceliac aortic flow waveforms and adjusted for patient body surface area, average resting heart rate, and blood pressure. Outlet boundary conditions consisted of three-element Windkessel models approximated from physiologic flow splits. Rigid wall flow simulations were then performed on preoperative and postoperative models with the same inflow and outflow conditions. We used SimVascular's incompressible Navier-Stokes solver to perform blood flow simulations on a cluster using 72 cores.Results: Preoperative and postoperative flow simulations were performed for 10 patients undergoing fEVAR with a total of 30 target vessels (20 renal stents, 10 mesenteric scallops). Postoperative models required a higher mean number of mesh elements to reach mesh convergence (3.2 ± 1.8 * 106 vs 2.6 ± 1.1 * 106; P = .005) with a longer mean computational time (10.3 ± 6.3 hours vs 7.8 ± 3.5 hours; P = .04) compared with preoperative models. fEVAR was associated with small but statistically significant increases in mean peak proximal aortic arterial pressure (140.3 ± 11.0 mm Hg vs 136.9 ± 8.7 mm Hg; P = .02) and peak renal artery pressure (131.6 ± 14.8 mm Hg vs 128.9 ± 11.8 mm Hg; P = .04) compared with preoperative simulations. No differences were observed in peak pressure in the celiac, superior mesenteric, or distal aortic arteries (P = .17-.96). When measuring blood flow, the only observed difference was an increase in peak renal flow rate after fEVAR (17.5 ± 3.8 mL/s vs 16.9 ± 3.5 mL/s;P =.04). fEVAR was not associated with changes in the mean pressure or the mean flow rate in the celiac, superior mesenteric, or renal arteries (P = .06-.98). Stenting of the renal arteries did not induce significant changes time-averaged wall shear stress in the proximal renal artery (23.4 ± 8.1 dynes/cm2 vs 23.2 ± 8.4 dynes/cm2; P = .98) or distal renal artery (32.7 ± 13.9 dynes/cm2 vs 29.6 ± 11.8 dynes/cm2; P = .23). In addition, computational visualization of crosssectional velocity profiles revealed low flow disturbances associated with protrusion of renal graft fabric into the aortic lumen.Conclusions: In a pilot study involving a selective cohort of patients who underwent uncomplicated fEVAR, patient-specific flow modelling was a feasible method for assessing the hemodynamic performance of various two-vessel fenestrated device configurations and revealed subtle differences in computationally derived peak branch pressure and blood flow rates. Structural changes in aortic flow geometry after fEVAR do not seem to affect computationally estimated renovisceral branch perfusion or wall shear stress adversely. Additional studies with invasive angiography or phase contrast magnetic resonance imaging are required to clinically validate these findings.

    View details for DOI 10.1016/j.jvssci.2020.11.032

    View details for PubMedID 34258601

  • Respiratory-induced changes in renovisceral branch vessel morphology after fenestrated thoracoabdominal aneurysm repair with the BeGraft balloon-expandable covered stent. Journal of vascular surgery Tran, K., Suh, G. Y., Mougin, J., Haulon, S., Cheng, C. 2021

    Abstract

    We evaluated the respiratory-induced changes in branch vessel geometry after thoracoabdominal fenestrated endovascular aneurysm repair (fEVAR) with the Bentley BeGraft graft (Innomed GmbH, Hechingen, Germany) as the covered bridging stent.Patients treated with fEVAR for thoracoabdominal aortic aneurysms with a custom-made Zenith fenestrated endograft (Cook Medical Europe Ltd, Limerick, Ireland) and Bentley BeGraft peripheral stents were prospectively recruited. Using SimVascular software (Open-Source Medical Software Corp, San Diego, CA), the pre- and postoperative aortic and branch contours were segmented from computed tomography angiograms performed during inspiratory and expiratory breath-holds. The centerlines were extracted from the lumen contours, from which the branch take-off angles, distal stent angles, and peak branch curvature changes were computed. Paired, two-tailed t tests were performed to compare the pre- and postoperative deformations.Renovisceral vessel geometry was evaluated in 12 patients undergoing fEVAR with a total of 46 target vessels (10 celiac arteries, 12 superior mesenteric arteries [SMAs], 24 renal arteries). Implantation of BeGraft bridging stents was associated with a significant reduction in respiration-induced changes in vessel branch angulation (Δ5.3° ± 3.9° vs Δ12.0° ± 8.3° [postoperative vs preoperative]; P = .001) and mean curvature (0.72 ± 0.22 cm-1 vs 0.53 ± 0.18 cm-1) in the renal arteries, without significant changes in the celiac arteries or SMAs. No significant difference was found in end-stent angle motion in the renal arteries (P = .77), celiac arteries (P = .34), or SMAs (P = .55). The maximum local vessel curvature change decreased after fEVAR in the SMAs (Δ0.28 cm-1 vs Δ0.47 cm-1; P = .04) but was unchanged in the celiac (P = .61) and renal (P = .51) arteries.Implantation of the BeGraft as a bridging stent in fEVAR was associated with decreased respiratory-induced deformation in the renal branch take-off angulation and mean renal artery curvature, with reduced maximum curvature bending in the SMA compared with the preoperative anatomy. However, the BeGraft allowed for celiac and renal artery bending similar to that in the native preoperative state. These findings suggest that the use of BeGraft peripheral stents with fEVAR will closely mimic the native arterial branch geometry and vessel conformability caused by relatively aggressive respiratory motion.

    View details for DOI 10.1016/j.jvs.2020.12.093

    View details for PubMedID 33548438

  • Predictors of Sac Regression after Fenestrated Endovascular Aneurysm Repair. Journal of vascular surgery Li, M., Stern, J. R., Tran, K., Deslarzes-Dubuis, C., Lee, J. T. 2021

    Abstract

    Aneurysm sac regression after standard endovascular aortic repair is associated with improved outcomes, but similar data are limited after fenestrated endovascular aortic repair (FEVAR). We sought to evaluate sac regression after FEVAR, and identify any predictors of this favorable outcome.Patients undergoing elective FEVAR using the commercially available Zenith Fenestrated device (ZFEN; Cook Medical, Bloomington, IN) from 2012 to 2018 at a single institution were retrospectively reviewed. Maximal aortic diameter was compared between the preoperative scan and those obtained in follow-up. Patients with ≥5 mm sac regression were included in the REG group, with all others in the NON-REG group. Outcomes were compared between groups using univariate analysis, and logistic regression analysis was performed to identify any predictive factors for sac regression.132 FEVAR patients were included in the analysis. At a mean follow-up of 33.1 months, 65 patients (49.2%) had sac regression ≥5 mm and comprised the REG group (N=65, 49.2%). The REG group had smaller diameter devices, and were less likely to have had concomitant chimney grafts placed (P <0.05). The NON-REG group had a higher incidence of type II endoleak (35.8% vs. 12.3%; P=0.002). Sac regression was associated with a significant mortality benefit on Kaplan-Meier analysis (log rank; P=0.02). Multivariate analysis identified adjunctive parallel grafting (OR 0.01, 95% CI 0.03-0.36; P <0.01), persistent type II endoleak (OR 0.13, 95% CI 0.02-0.74; P <0.01), and increased number of target vessels (OR 0.25, 95% CI 0.10-0.62, P=0.002) as independent predictors of failure to regress.Sac regression after FEVAR occurred in nearly half of patients, but appears to be less common in patients with persistent type II endoleaks and those undergoing concomitant parallel grafting. Sac regression was associated with a significant survival advantage, and can be used as a clinical marker for success after FEVAR.

    View details for DOI 10.1016/j.jvs.2021.08.067

    View details for PubMedID 34506890

  • Renal stent complications and impact on renal function following standard fenestrated endovascular aneurysm repair. Annals of vascular surgery Deslarzes-Dubuis, C., Tran, K., Colvard, B. D., Lee, J. T. 2020

    Abstract

    OBJECTIVES: To report renal outcomes including long-term patency, secondary interventions, and related renal function following fenestrated endovascular aortic repair (fEVAR).MATERIALS AND METHODS: Single center retrospective review of patients undergoing fEVAR between 2012-2018 using the Cook-ZFEN device. Renal stent complications, defined as any stenosis, occlusion, kink, renal stent related endoleak, and reinterventions were tabulated. Estimated glomerular filtration rate (GFR) was estimated using the MDRD formula.RESULTS: During the study period, 114 patients underwent elective fEVAR. Of 329 total target vessels, 193 renal arteries were stented (133 Atrium iCAST, 60 Gore VBX). Technical success was achieved in 97.4% and the mean follow-up was 23.3 months. 17 renal complications occurred in 14 patients (12.3%), including 4 occlusions, 9 stenosis, 3 dislocations and 1 type 3 endoleak. All stent complications underwent endovascular reintervention with a median hospital stay of 1 day (0-10) and a technical success of 94.2%. One patient suffered renal hemorrhage that warranted embolization. Patients with occlusion were treated the day of diagnosis, and mean time from diagnosis to intervention for stenosis was 21.5 days. Estimated primary patency was 92.1 % and 81.5% at 24 and 48 months respectively. On multivariate analysis, larger native renal artery diameter was the only independent protective factor against patency loss (HR 0.23(0.09-0.59)). Secondary patency at latest follow-up was 99.4%. Mean eGFR was not significantly different at latest follow-up between patients with renal complications versus those without (43.75 vs 55.58 mL/min/1.73m2, p=.09). Comparing patients with and without renal stent complications, 81.4% and 72.7% of patients had stable or improved renal disease by CKD staging compared to baseline (P=.51).CONCLUSIONS: fEVAR is a durable option for the treatment of juxtarenal aortic aneurysms and is associated with excellent secondary patency. Renal stent complications have no significant impact on renal function, but smaller native renal arteries are at higher risk of stent graft complications.

    View details for DOI 10.1016/j.avsg.2020.10.020

    View details for PubMedID 33249133

  • Paclitaxel exposure and long-term mortality of patients treated with the Zilver PTX drug-eluting stent. Vascular Stern, J. R., Tran, K., Chandra, V., Harris, E. J., Lee, J. T. 2020: 1708538120964371

    Abstract

    OBJECTIVES: Paclitaxel-eluting stents have demonstrated improved patency over balloon angioplasty and bare metal stenting for endovascular interventions in the femoral-popliteal segment. Recently, concerns have arisen regarding the safety of paclitaxel use and its association with mortality. This study aims to examine real-world, long-term mortality, and patency of patients treated with the Zilver PTX drug-eluting stent.METHODS: Patients treated with the PTX stent after FDA approval between 2013 and 2015 were identified from an institutional database. Demographic, procedural, and device information was collected and initial- and lifetime-exposure dose of paclitaxel was calculated. The primary outcome was all-cause mortality and its association with paclitaxel exposure. Long-term patency was also evaluated.RESULTS: Seventy-nine procedures involving PTX placement were performed on 64 individual patients during the study period, with 15 (23.4%) having bilateral procedures. Average age was 70 years, and 71.9% were male. Forty-five patients (70.3%) were claudicants, and 19 (29.7%) had chronic, limb-threatening ischemia. An average of 2.3 PTX stents, totaling 203 mm in length, were placed per procedure. Paclitaxel exposure was 1.87mg/procedure initially (range 0.38-4.03mg), and average lifetime exposure was 4.65mg/patient (range 0.38-27.91mg). Average follow-up was 59.6 months. Kaplan-Meier estimated survival was 96.9%, 81.2% and 71.7% at one , three, and five years. On multivariate analysis, no specific factors were associated with overall morality including initial paclitaxel dose (HR 0.99, 95% CI 0.99-1.00) and lifetime paclitaxel exposure (HR 0.98, 95% CI 0.89-1.08). Kaplan-Meier primary patency was 76.2%, 60.1%, and 29.3% at one, two, and five years, respectively. Secondary patency was 92.2%, 85.4%, and 75.2% at the same intervals.CONCLUSIONS: At a mean follow-up of five years, exposure to higher doses of paclitaxel from Zilver PTX does not appear to be associated with increased mortality compared to lower doses in real-world patients. Long-term patency rates confirm the efficacy of Zilver PTX, and further investigation may be warranted before abandoning paclitaxel use altogether.

    View details for DOI 10.1177/1708538120964371

    View details for PubMedID 33054678

  • Mid-Term Survival after Thoracic Endovascular Aortic Repair by Indication in the Medicare Population. Journal of the American College of Surgeons Ho, V. T., Itoga, N. K., Tran, K., Lee, J. T., Stern, J. R. 2020

    Abstract

    BACKGROUND: Thoracic endovascular aortic repair (TEVAR) is indicated for treatment of aneurysms, dissections, and traumatic injury. We describe mid-term mortality and re-intervention rates in Medicare beneficiaries undergoing TEVAR.STUDY DESIGN: Patients who underwent TEVAR between 2006-2014 were identified by Current Procedural Terminology (CPT) codes in a 20% Medicare sample. Indication for aortic repair (aneurysm, dissection, trauma) was ascertained via International Classification of Diseases (ICD-9) codes. Follow-up was evaluated until 2015. Kaplan Meier survival analysis and Cox regression were used to compare mortality, with re-intervention and mortality rates expressed as a composite outcome in a hazard ratio with 95% confidence interval (HR 95%CI).RESULTS: 3095 patients underwent TEVAR during the study period: 1465 (47%) for aneurysm 1448 (47%) for dissection, and 182 (5.9%) for trauma. Mean patient age was 74.4 years, and 44.5% were female. Median follow-up was 2.7 years. The overall 30-day, 1-year, and 5-year, and 8-year survival was 93%, 78%, 49%, and 33%, respectively. 30-day mortality was highest in traumatic indications, but overall mortality was highest in patients undergoing TEVAR for aneurysm. Freedom from combined re-intervention and mortality at 30-days, 1-year, 5-years and 8-years was 89%, 73%, 43%, and 29% respectively. Reintervention was highest in patients undergoing TEVAR for dissection (12.8%), followed by aneurysm (10.0%) and trauma (5.5%). Advanced age (HR 1.03 per year, 95%CI 1.02-1.03), congestive heart failure (CHF) (HR 1.48, 95%CI 1.33-1.65), dementia (HR 1.40, 95%CI 1.14-1.28), and rupture (HR 1.38, 95%CI 1.24-1.54) were associated with mortality.CONCLUSION: Midterm survival is lower in patients who undergo TEVAR for dissection and aneurysm compared to trauma. Aneurysmal disease, advanced age, CHF, dementia and aortic rupture are associated with mortality and re-intervention in TEVAR.

    View details for DOI 10.1016/j.jamcollsurg.2020.09.011

    View details for PubMedID 33022404

  • Results of chimney endovascular aneurysm repair as used in the PERICLES Registry to treat patients with suprarenal aortic pathologies JOURNAL OF VASCULAR SURGERY Taneva, G. T., Criado, F. J., Torsello, G., Veith, F., Scali, S. T., Kubilis, P., Donas, K. P., PERICLES Collaborators 2020; 71 (5): 1521-+

    Abstract

    The prevailing evidence calls for using chimney/snorkel endovascular repair (ch-EVAR) with one or two chimney grafts. No studies up to now focus on its applicability and results for the treatment of suprarenal aortic pathologies (SRAP). Hence, we evaluated the clinical and radiologic results of ch-EVAR treatment for SRAP placing three or more chimney grafts within the PERICLES Registry.Data from 517 patients suffering complex aortic pathologies treated by ch-EVAR between 2008 and 2014 at 13 European and U.S. centers were retrospectively reviewed and analyzed.Sixty-seven ch-EVAR-treated patients (12.9% of the entire PERICLES cohort) presented SRAP (83.5% elective, 16.5% urgent). The majority of patients (95.5%) received three chimney grafts; four patients received four chimney grafts. The Endurant device was the most commonly used (35.8%) followed by the Zenith abdominal endograft (19.4%). Overall, 204 chimney grafts were placed (56.7% covered self-expandable, 40.3% covered balloon-expandable stents, and 10.4% bare metal balloon-expandable stents). At a median follow-up of 24 months (range, 0.1-67.0 days), 30-day mortality was 6.1% (4 patients), and the overall mortality was 16.4% (11 patients). Overall survival was 87.4% (range, 79.5%-96.0%) at 1 year, 81.8% (range, 72.2%-92.2%) at 2 years and thereafter. Type IA endoleak was noted in nine patients (13.4%) intraoperatively and successfully treated in seven cases (97.1% technical success). Aneurysm sac diameter significantly decreased from 70.5 ± 19.3 mm to 66.9 ± 20.6 mm (P < .001) at last follow-up. Ischemic stroke or transient ischemic attack were noted in two patients (2.9%). Chimney occlusion was detected in six renal arteries (9.5%) and two superior mesenteric arteries (3.2%). No patients required chronic hemodialysis. All occluded superior mesenteric artery grafts were successfully rescued using endovascular approaches.The midterm use of ch-EVAR for the treatment SRAP seems to be safe, highlighting its applicability for the treatment of rupture threatening pathologies and seal zone lengthening as in type IA endoleaks after EVAR. However, the incidence of type IA endoleaks, chimney graft occlusions, and ischemic stroke rates is higher compared with the prevailing single chimney evidence. Longer follow-up with more cases is needed to establish the exact performance of this treatment in SRAP.

    View details for DOI 10.1016/j.jvs.2019.08.228

    View details for Web of Science ID 000528496800011

    View details for PubMedID 31611110

  • Even More Real World Data Regarding ChEVAR Continuing to Show Consistent Results. European journal of vascular and endovascular surgery : the official journal of the European Society for Vascular Surgery Tran, K., Lee, J. T. 2020

    View details for DOI 10.1016/j.ejvs.2020.01.003

    View details for PubMedID 32008932

  • Long-term chimney/snorkel EVAR experience for complex abdominal aortic pathologies within the PERICLES Registry. Journal of vascular surgery Taneva, G. T., Lee, J. T., Tran, K. n., Dalman, R. n., Torsello, G. n., Fazzini, S. n., Veith, F. J., Donas, K. P. 2020

    Abstract

    Early and short-term efficacy of the snorkel/chimney technique (ch-EVAR) have been previously reported. However, long-term ch-EVAR performance, vessel patency, and patient survival remain unknown. Our study aimed to evaluate the late outcomes and to identify possible predictors for failure within the PERICLES registry.Clinical and radiographic data from patients receiving ch-EVAR between 2008-2014 in the PERICLES registry were updated with extension of the follow-up. Regression models were used to evaluate relevant anatomic and operative characteristics as factors influencing late results focusing on patients with at least 30 months of follow-up (mean 46.6 months; range 30-120 months).517 patients from the initial PERICLES registry were included in this analysis, from which mean follow-up was updated from previously 17.1 to 28.2 months (range, 1-120 months). All-cause mortality at latest follow-up was 25.5% (n=132), with an estimated patient survival of 87.6%, 74.4% and 66.1% at one, three and five years, respectively. A sub-group of 244 patients with 387 chimney grafts placed (335 renal, 42 SMAs, 10 celiac arteries) and follow-up of at least 30 months was used to analyze specific anatomic and device predictors of adverse events. In the sub-group, the technical success was 88.9%, while primary patency was 94%, 92.8%, 92%, and 90.5% at 2.5 years, 3 years, 4 years and 5 years respectively. Mean aneurysm sack regression was 7.8±11.4 mm,p<.0001. Chimney graft occlusion occurred in 24 target vessels(6.2%). Late open conversion was required in 5 patients for endograft infection(n=2), persistent T1a endoleak (n=2) and endotension (n=1), The absence of infrarenal neck (OR 2.86 [1.32-6.19], p=.007) was significantly associated with long-term device-related complications. Sealing zone diameter > 30mm was significantly associated with persistent/late type Ia endoleak (T1a EL)(OR 4.86 [1.42-16.59], p=.012).The present analysis of the PERICLES registry provides the missing long-term experience on the ch-EVAR technique showing favorable results with more than half of the patients surviving for more than 5 years and chimney graft branch vessels patency of 92%. The absence of infrarenal neck and treatment with sealing zone diameter >30mm were the main anatomical long-term limits of the technique demanding adequate preoperative planning and indication.

    View details for DOI 10.1016/j.jvs.2020.10.086

    View details for PubMedID 33259893

  • Ask the experts: Which device combinations work best in your hands for parallel grafting and why? Endovascular Today Woo, E., Ronchey, S., Tran, K., Lee, J. 2020
  • Thoracic Aortic Dilation Following Endovascular Repair of Blunt Traumatic Aortic Injury. Annals of vascular surgery Tran, K. n., Li, M. n., Stern, J. R., Lee, J. T. 2020

    Abstract

    Thoracic endovascular aneurysm repair (TEVAR) has become the current standard of care for emergent treatment of blunt traumatic aortic injuries (BTAI). Although aortic dilation of the infrarenal neck following EVAR for aortic aneurysms has been studied, changes in aortic diameter following TEVAR for BTAI is not well understood. This study aims to characterize changes in thoracic aortic diameter following stent graft placement in the setting of non-aneurysmal traumatic aortic injury.A single-center, retrospective review was performed involving patients presenting with BTAI treated with TEVAR. Only patients with at least 12 months follow-up were included. Aortic diameter, defined as the outer-to-outer diameter on 3D center-line imaging, was measured at six locations along the proximal and mid thoracic aorta. The first post-operative CT (≤1 month) served as a baseline from which interval measurements were compared.Twenty patients with BTAI treated from 2011-2017 had adequate imaging available for review and were included in this study cohort. Median follow-up time was 46.8 (12-80, range) months. At latest follow-up, aortic dilation (AD) occurred at all measured locations within the endograft, starting from the proximal graft edge (0.62±0.69mm, p=.027) to the distal graft edge (1.21±1.28mm, p=.003). AD was most pronounced in the distal graft segment 2cm proximal to the distal graft edge, with a mean AD of 1.32±1.59mm (+5.3%, p<.001). At this location, AD was found to increase in a linear manner with an estimated rate of 0.67±0.20mm /year (p=0.006). The native aorta proximal and distal to the endograft was not found to significantly dilate during follow-up (p=.280-.897). 70% of patients were found to have AD >5%. The amount of aortic dilation was not found to be associated with either graft oversizing (p=.151) or age (p=.340). There were no cases of graft migration, erosion or endoleak.Aortic dilation is a common benign finding after TEVAR for BTAI. AD is most pronounced at the near the distal end of the stent graft. In late-term follow-up, there are no known associated complications related to AD.

    View details for DOI 10.1016/j.avsg.2020.06.049

    View details for PubMedID 32603842

  • Comparison of mid-term graft patency in common femoral versus superficial femoral artery inflow for infra-geniculate bypass in the vascular quality initiative. Vascular Tran, K. n., Ho, V. T., Itoga, N. K., Stern, J. R. 2020: 1708538120924908

    Abstract

    The superficial femoral artery can be used as inflow for infra-geniculate bypass, but progressive proximal occlusive disease may affect graft durability. We sought to evaluate the effect of superficial femoral artery versus common femoral artery inflow on infra-geniculate bypass patency within a large contemporary multicenter registry.The vascular quality initiative was queried from 2013 to 2019 to identify patients with >30-day patency follow-up, Rutherford chronic limb ischemia stage 1-6, and an infra-geniculate bypass, excluding those with prior ipsilateral bypass. The cohort was stratified by inflow vessel, with primary, primary-assisted, and secondary patency serving as the primary outcome variables. Multivariate Cox-proportional hazard models and radius-based propensity-score matching were performed to reduce treatment-selection bias due to clinical covariates.A total of 11,190 bypass procedures were performed (8378 common femoral artery inflow, 2812 superficial femoral artery) on 10,110 patients, with a mean follow-up of 12.8 months (range 1-98). Patients receiving superficial femoral artery inflow bypasses were more commonly male (p = 0.002), obese (p < 0.0001) and had chronic, limb threatening ischemia (p < 0.0001), whereas those with common femoral artery inflow were older (p < 0.0004), and had higher baseline comorbidities including smoking (p < 0.0001), coronary disease (p < 0.0001), and pulmonary disease (p < 0.0001). On life-table analysis, there was no significant difference in three year estimated primary (32.1 vs 30.1%, p = 0.928), primary assisted (60.5 vs 65.8%, p = 0.191), or secondary patency (62.5 vs 66.7%, p = 0.139) between superficial femoral artery and common femoral artery inflow groups, respectively. A multivariate Cox model found no significant association between inflow vessel and primary patency (0.96 [0.88-1.04], HR [95%CI]), primary-assisted (1.07 [0.95-1.20], HR [95%CI]), or secondary patency (1.08 [0.96-1.22]). In a propensity-matched cohort (n = 11,151), there were small but statistically significant differences in primary, primary-assisted, and secondary patency at latest follow-up (non-time-to-event data) between groups. The largest difference was observed when evaluating secondary patency, with common femoral artery inflow having a marginally higher secondary patency of 88.1% compared to 85.6% for those with superficial femoral artery inflow at latest follow-up (p = 0.009).Within the vascular quality initiative, there is no significant difference in life-table determined three-year primary, primary-assisted, and secondary patency between infra-geniculate bypasses using common femoral artery inflow compared to superficial femoral artery inflow. Small, statistically significant differences exist in primary, primary-assisted, and secondary patency favoring common femoral artery inflow after propensity score matching. Long-term follow-up data are required in the vascular quality initiative to better evaluate bypass graft durability as this study was limited by a mean follow-up of one year.

    View details for DOI 10.1177/1708538120924908

    View details for PubMedID 32408857

  • Innovative Technique for Below the Knee Arterial Revascularisation Using Porcine Self Made Stapled Pericardial Tube Grafts. EJVES vascular forum Cote, E., Trunfio, R., Deslarzes-Dubuis, C., Tran, K., Corpataux, J., Deglise, S. 2020; 48: 23–26

    Abstract

    Introduction: When no autologous vein is available for distal bypass in the setting of chronic limb threatening ischaemia (CLTI), new alternatives are required to solve the problems of availability, patency, and resistance to infection. An innovative technique of below the knee bypass for CLTI using a porcine self made stapled pericardial tube graft is reported.Report: An 84 year old man, admitted with right CLTI with foot infection due to long occlusion of the femoropopliteal segment, required urgent revascularisation. In the absence of autologous vein and cryopreserved vessels, a 4 mm self made stapled porcine pericardial tube graft 56 cm long was created from two 14* 8 cm patches, to perform a femorotibioperoneal trunk bypass. On day 10, bypass thrombectomy and balloon angioplasty of the distal anastomosis were needed to treat early occlusion. Oral anticoagulation was then started. Right toe pressure increased from 0 to 70mmHg, and no infection was reported. Complete wound healing was achieved. At six months, the bypass was still patent.Discussion: The use of porcine self made stapled pericardial tube grafts could offer new options for revascularisation in CLTI. Larger cohort studies with longer follow up are needed to confirm this successful preliminary experience.

    View details for DOI 10.1016/j.ejvsvf.2020.06.002

    View details for PubMedID 33078165

  • Quantification of suprarenal aortic neck dilation after fenestrated endovascular aneurysm repair. Journal of vascular surgery Tran, K. n., Deslarzes-Dubuis, C. n., Lee, J. T. 2020

    Abstract

    Suprarenal aortic neck dilation (AND) after fenestrated endovascular aneurysm repair (FEVAR) with commercially available devices has not yet been well characterized. The aim of this study was to measure diameter changes in the supravisceral aorta after FEVAR.This is a single-center retrospective review involving patients with juxtarenal aneurysms treated with Cook ZFEN devices (Cook Medical, Bloomington, Ind). Patients with at least 1 year of cross-sectional radiologic follow-up were included. AND was defined as ≥3 mm at any measured location. Aortic diameter, defined as the average outer to outer diameter on three-dimensional centerline imaging, was measured at seven locations along the length of the ZFEN device from the proximal fixation struts to the bottom of the second seal stent. The first postoperative CT scan (≤1 month) served as a baseline from which subsequent measurements at annual intervals were compared.A total of 43 patients who underwent FEVAR from 2012 to 2018 met inclusion criteria, with a total of 119 target vessels (83 renal stents, 41 superior mesenteric artery scallops or large fenestrations). Mean follow-up time was 30.3 months. Any AND was found to occur in 32 (74.4%) patients. Aortic diameter dilation at latest follow-up was found to occur at all measured locations from the top of the fixation struts (1.9 ± 2.4 mm; P < .0001) to the middle of the second seal stent (1.3 ± 3.8 mm; P < .01). Diameter growth was most pronounced in the middle of the first seal stent, with mean AND of 3.6 ± 3.2 mm. At this location, the aorta experienced nearly linear annual growth of 0.99 mm (95% confidence interval, 0.7-1.28 mm) per year. Increasing device oversizing relative to the native visceral aorta was the strongest predictor of postoperative neck diameter growth (1.34 mm per 10% increase in oversizing; P = .02), whereas increasing proximal seal length was protective of growth (-1.82 mm per 10-mm increase in seal length; P = .016). Proximal seal lengths ≥3 cm were associated with less neck dilation compared with <3 cm (2.6 mm vs 4.9 mm; P = .022). Type IA endoleak in this cohort was rare (n = 1) and not associated with AND (P = .256).Dilation of the suprarenal aorta is a common finding in midterm follow-up after FEVAR and not associated with proximal endoleak. Aggressive device oversizing is predictive of dilation, whereas longer seal lengths are associated with less dilation along the suprarenal seal zone. These results support the continued use of FEVAR for juxtarenal aneurysms, particularly in patients in whom ≥3 cm of healthy seal length can be obtained.

    View details for DOI 10.1016/j.jvs.2020.04.522

    View details for PubMedID 32445831

  • Multivessel tibial revascularization does not improve outcomes in patients with critical limb ischemia. Journal of vascular surgery Lavingia, K. S., Tran, K., Dua, A., Itoga, N., Deslarzes-Dubuis, C., Mell, M., Chandra, V. 2019

    Abstract

    OBJECTIVE: Multivessel tibial revascularization for critical limb ischemia (CLI) remains controversial. The purpose of this study was to evaluate single vs multiple tibial vessel interventions in patients with multivessel tibial disease. We hypothesized that there would be no difference in amputation-free survival between the groups.METHODS: Using the Vascular Quality Initiative registry, we reviewed patients undergoing lower extremity endovascular interventions involving the tibial arteries. Patients with CLI were included only if at least two tibial vessels were diseased and adequate perioperative data and clinical follow-up were available for review. The primary outcome was amputation-free survival.RESULTS: There were 10,849 CLI patients with multivessel tibial disease evaluated from 2002 to 2017; 761 limbs had adequate data and follow-up available for review. Mean follow-up was 337± 62days. Of these, 473 (62.1%) underwent successful single-vessel tibial intervention (group SV), whereas 288 (37.9%) underwent successful multivessel (two or more) intervention (group MV). Patients in group MV were younger (69.1 vs 73.2years; P< .001), with higher tobacco use (29.5% vs 18.2%; P< .001). Group SV more commonly had concurrent femoral or popliteal inflow interventions (83.7% vs 78.1%; P= .05). Multivessel runoff on completion was significantly greater for group MV (99.9% vs 39.9%; P< .001). No differences were observed between group SV and group MV for major amputation (9.0% and 7.6%; P= .6), with similar amputation-free survival at 1year (90.6% vs 92.9%; P= .372). In a multivariate Cox model, loss of patency was the only significant predictor of major amputation (hazard ratio, 5.36 [2.7-10.6]; P= .01). A subgroup analysis of 355 (46.6%) patients with tissue loss data showed that tissue loss before intervention was not predictive of future major amputation.CONCLUSIONS: In the Vascular Quality Initiative registry, patients with CLI and occlusive disease involving multiple tibial vessels did not appear to have a limb salvage benefit from multiple tibial revascularization compared with single tibial revascularization.

    View details for DOI 10.1016/j.jvs.2019.08.251

    View details for PubMedID 31685281

  • Duplex ultrasound surveillance of renal branch grafts after fenestrated endovascular aneurysm repair. Journal of vascular surgery Tran, K., Mcfarland, G., Sgroi, M., Lee, J. T. 2019

    Abstract

    OBJECTIVE: The use of duplex ultrasound (DUS) examinations for surveillance after fenestrated endovascular aneurysm repair (FEVAR) is not well-studied. Our objective was to further characterize normal and abnormal duplex findings in renal branch grafts after FEVAR.METHODS: We retrospectively reviewed a single-center experience involving consecutive patients treated with Cook ZFEN devices between 2012 and 2017. Postoperative imaging consisted of a computed tomography (CT) scan at 1month, 6months, 1year, and annually thereafter. As experienced progressed, DUS examination with or without concurrent CT scans were obtained in a nonstandardized protocol, particularly for patients with decreased renal function. Renal patency loss was defined as occlusion or stenosis of greater than 50% evaluated on 3-day renal artery center-line imaging.RESULTS: A total of 116 patients were treated with FEVAR, of which 60 (51.7%) had concurrent CT and renal DUS images available for review. Six patients (10%) had limited ultrasound studies owing to bowel gas and were excluded. The study cohort therefore included 54 patients receiving of 94 renal fenestrated stents with a mean follow-up of 23months. Twelve cases of renal patency loss in 10 patients (9 stenoses, 3 occlusions) were found on CT scanning, 11 (91.6%) of which had concurrent abnormalities found on ultrasound examination. Stents with compression at the junction of the main body exhibited significantly elevated mean Peak systolic velocities (PSV) compared with nonstenosed stents (349.2cm/s vs 115.3cm/s; P= .003). Stenosis in the most proximal portion of the stent (ie, within the main body) showed no difference in proximal PSV (86.0cm/s vs 131.9cm/s; P= .257); however, dampened PSV showed significant differences in the mid (17.5cm/s vs 109.9cm/s; P= .027) and distal (19.0cm/s vs 78.3cm/s; P= .028) segments compared with nonstenosed stents. All occluded stents demonstrated no flow detection. Proximal PSV served as a strong classifier for junctional stenosis (area under the curve, 0.98). A combined criterion of proximal PSV of greater than 215cm/s or distal PSV of less than 25cm/s resulted in a sensitivity of 91.6% and specificity of 85.3% for detecting patency loss. All stents that were compromised underwent successful secondary reintervention and restoration of patency.CONCLUSIONS: DUS imaging is a clinically useful modality for surveillance of renal branch grafts after FEVAR. Patterns of segmental velocity elevation (proximal PSV, >215cm/s) and dampening in the distal renal indicate potential hemodynamic compromise and should prompt more aggressive workup or imaging and likely be considered for secondary intervention.

    View details for DOI 10.1016/j.jvs.2018.12.050

    View details for PubMedID 31327607

  • Use of Bare Metal Chimney Stents in the Treatment of Juxtarenal Aortic Aneurysms: "Do Not Praise the Day Before Evening" JOURNAL OF ENDOVASCULAR THERAPY Donas, K. P., Taneva, G. T., Li, Y., Tran, K., Torsello, G. 2019; 26 (3): 359–60
  • Infrarenal endovascular aneurysm repair with large device (34- to 36-mm) diameters is associated with higher risk of proximal fixation failure. Journal of vascular surgery McFarland, G., Tran, K., Virgin-Downey, W., Sgroi, M. D., Chandra, V., Mell, M. W., Harris, E. J., Dalman, R. L., Lee, J. T. 2019; 69 (2): 385–93

    Abstract

    OBJECTIVE: Endovascular aneurysm repair (EVAR) has become the standard of care for infrarenal aneurysms. Endografts are commercially available in proximal diameters up to 36mm, allowing proximal seal in necks up to 32mm. We sought to further investigate clinical outcomes after standard EVAR in patients requiring large main body devices.METHODS: We performed a retrospective review of a prospectively maintained database for all patients undergoing elective EVAR for infrarenal abdominal aortic aneurysms at a single institution from 2000 to 2016. Only endografts with the option of a 34- to 36-mm proximal diameter were included. Requisite patient demographics, anatomic and device-related variables, and relevant clinical outcomes and imaging were reviewed. The primary outcome in this study was proximal fixation failure, which was a composite of type IA endoleak and stent graft migration >10mm after EVAR. Outcomes were stratified by device diameter for the large-diameter device cohort (34-36mm) and the normal-diameter device cohort (<34mm).RESULTS: There were 500 patients treated with EVAR who met the inclusion criteria. A total of 108 (21.6%) patients received large-diameter devices. There was no difference between the large-diameter cohort and the normal-diameter cohort in terms of 30-day (0.9% vs 0.95%; P= .960) or 1-year mortality (9.0% vs 6.2%; P= .920). Proximal fixation failure occurred in 24 of 392 (6.1%) patients in the normal-diameter cohort and 26 of 108 (24%) patients in the large-diameter cohort (P<.001). There were 13 (3.3%) type IA endoleaks in the normal-diameter cohort and 16 (14.8%) in the large-diameter cohort (P< .001). Stent graft migration (>10mm) occurred in 15 (3.8%) in the normal-diameter cohort and 16 (14.8%) in the large-diameter cohort (P< .001). After multivariate analysis, only the use of Talent (Medtronic, Minneapolis, Minn) endografts (odds ratio [OR], 4.50; 95% confidence interval [CI], 1.18-17.21) and neck diameter ≥29mm (OR, 2.50; 95% CI, 1.12-5.08) remained significant independent risk factors for development of proximal fixation failure (OR, 3.99; 95% CI, 1.75-9.11).CONCLUSIONS: Standard EVAR in patients with large infrarenal necks ≥29mm requiring a 34- to 36-mm-diameter endograft is independently associated with an increased rate of proximal fixation failure. This group of patients should be considered for more proximal seal strategies with fenestrated or branched devices vs open repair. Also, this group likely needs more stringent radiographic follow-up.

    View details for PubMedID 30686336

  • Complex endovascular aneurysm repair is associated with higher perioperative mortality but not late mortality compared with infrarenal endovascular aneurysm repair among octogenarians JOURNAL OF VASCULAR SURGERY Tran, K., Lee, A. M., McFarland, G. E., Sgroi, M. D., Lee, J. T. 2019; 69 (2): 327–33
  • Preprocedural Cross-Sectional Imaging Prior to Percutaneous Peripheral Arterial Disease Interventions. Vascular and endovascular surgery Itoga, N. K., Ho, V. T., Tran, K. n., Chandra, V. n., Dalman, R. L., Harris, E. J., Lee, J. T., Mell, M. W. 2019: 1538574419887585

    Abstract

    Preprocedural cross-sectional imaging (PCSI) for peripheral artery disease (PAD) may vary due to patient complexity, anatomical disease burden, and physician preference. The objective of this study was to determine the utility of PCSI prior to percutaneous vascular interventions (PVIs) for PAD. Patients receiving first time lower extremity angiograms from 2013 to 2015 at a single institution were evaluated for PCSI performed within 180 days, defined as computed tomography angiography (CTA) or magnetic resonance angiography (MRA) evaluating abdominal to pedal vasculature. The primary outcome was technical success defined as improving the target outflow vessels to <30% stenosis. Of the 346 patients who underwent lower extremity angiograms, 158 (45.7%) patients had PCSI, including 150 patients had CTA and 8 patients had MRA. Of these, 48% were ordered by the referring provider (84% at an outside institution). Preprocedural cross-sectional imaging was performed at a median of 26 days (interquartile range: 9-53) prior to the procedure. The analysis of the institution's 5 vascular surgeons identified PCSI rates ranging from 31% to 70%. On multivariate analysis, chronic kidney disease (odds ratio [OR] = 0.35; 95% confidence interval [CI]: 0.17-0.73) was associated with less PSCI usage, and inpatient/emergency department evaluation (OR = 3.20; 95% CI: 1.58-6.50) and aortoiliac disease (OR = 2.78; 95% CI: 1.46-5.29) were associated with higher usage. After excluding 31 diagnostic procedures, technical success was not statistically significant with PSCI (91.3%) compared to without PCSI (85.6%), P = .11. When analyzing 89 femoral-popliteal occlusions, technical success was higher with PCSI (88%) compared to procedures without (69%) P = .026. Our analysis demonstrates that routine ordering of PCSI may not be warranted when considering technical success of PVI; however, PCSI may be helpful in treatment planning. Further studies are needed to confirm these findings in another practice setting, with more prescriptive use of PCSI to improve procedural success, and thereby improve the value of PCSI.

    View details for DOI 10.1177/1538574419887585

    View details for PubMedID 31746279

  • Climbing-Related Injury Among Adults in the United States: 5-Year Analysis of the National Emergency Department Sample. Wilderness & environmental medicine Forrester, J. D., Tran, K., Tennakoon, L., Staudenmayer, K. 2018

    Abstract

    BACKGROUND: Rock climbing and mountaineering are popular outdoor recreational activities. More recently, indoor climbing has become popular, which has increased the number of persons at risk for climbing-related injuries.OBJECTIVE: To assess the morbidity, mortality, and healthcare cost due to climbing-related injury among persons presenting to US emergency departments (ED).METHODS: We performed a retrospective analysis of the 2010 to 2014 National Emergency Department Sample database, a nationally representative sample of all visits to US EDs. Rock climbing, mountain climbing, and wall climbing injuries were identified using International Classification of Diseases, Ninth Revision, Clinical Modification codes (E004.0). Outcomes evaluated included morbidity, mortality, inpatient admission, and costs. Adjusted analyses accounting for survey methodology were performed.RESULTS: A weighted-estimate 15,116 adult ED visits were associated with climbing-related injury. Patient age was 32.8±14.7 (mean±SD) (95% CI: 32.1-33.5) y, and 62% of patients were male. The majority of the injuries occurred in the Western census region (9593; 63%). Less than 1% of all climbing-related visits resulted in death. Only of injury severity score >15 was associated with death (P=0.005). A total of 1610 (11%) of patients were admitted as inpatients. Accounting for ED and inpatient costs, climbing-related injuries cost the US healthcare system approximately $102 (95% CI: $75-130) million USD for the 5-y period, averaging $20±9.5million USD per y.CONCLUSIONS: Most persons with climbing-related injuries presenting to EDs do not require inpatient admission. Although death is rare among patients with climbing-related injuries, the costs of injuries in survivors remain high.

    View details for PubMedID 30241931

  • Identification of optimal device combinations for the chimney endovascular aneurysm repair technique within the PERICLES registry JOURNAL OF VASCULAR SURGERY Scali, S. T., Beck, A. W., Torsello, G., Lachat, M., Kubilis, P., Veith, F. J., Lee, J. T., Donas, K. P., PERICLES Investigators 2018; 68 (1): 24–35

    Abstract

    The ideal stent combination for chimney endovascular aneurysm repair remains undetermined. Therefore, we sought to identify optimal aortic and chimney stent combinations that are associated with the best outcomes by analyzing the worldwide collected experience in the PERformance of chImney technique for the treatment of Complex aortic pathoLogiES (PERICLES) registry.The PERICLES registry was reviewed for patients with pararenal aortic disease electively treated from 2008 to 2014. Eleven different aortic devices were identified with three distinct subgroups: group A (n = 224), nitinol/polyester; group B (n = 105), stainless steel/polyester; and group C (n = 69), nitinol/expanded polytetrafluoroethylene. The various chimney stent subtypes included the balloon-expandable covered stent (BECS), self-expanding covered stent, and bare-metal stent. Deidentified aortic and chimney device combinations were compared for risk of chimney occlusion, type IA endoleak, and survival. Effects of high-volume centers (>100 cases), use of an internal lining chimney stent, number of chimney stents, and number of chimney stent subtypes deployed were also considered. We considered demographics, comorbidities, and aortic anatomic features as potential confounders in all models.The 1- and 3-year freedom from BECS chimney occlusion was not different between groups (group A, 96% ± 2% and 87% ± 5%; groups B and C, 93% ± 3% and 76% ± 10%; Cox model, P = .33). Similarly, when non-BECS chimney stents were used, no difference in occlusion risk was noted for the three aortic device groupings; however, group C patients receiving BECS did have a trend toward higher occlusion risk relative to group C patients not receiving a BECS chimney stent (hazard ratio [HR], 4.0; 95% confidence interval [CI], 0.85-18.84; P = .08). Patients receiving multiple chimney stents, irrespective of stent subtype, had a 1.8-fold increased risk of occlusion for each additional stent (HR, 1.8; 95% CI, 1.2-2.9; P = .01). Use of a bare-metal endolining stent doubled the occlusion hazard (HR, 2.1; 95% CI, 1.0-4.5; P = .05). Risk of type IA endoleak (intraoperatively and postoperatively) did not significantly differ for the aortic devices with BECS use; however, group C patients had higher risk relative to groups A/B without BECS (C vs B: odds ratio [OR], 3.2 [95% CI, 1-11; P = .05]; C vs A/B: OR, 2.4 [95% CI, 0.9-6.4; P = .08]). Patients treated at high-volume centers had significantly lower odds for development of type IA endoleak (OR, 0.2; 95% CI, 0.1-0.7; P = .01) irrespective of aortic or chimney device combination. Mortality risk was significantly higher in group C + BECS vs group A + BECS (HR, 5.3; 95% CI, 1.6-17.5; P = .006). The 1- and 3-year survival for groups A, B, and C (+BECS) was as follows: group A, 97% ± 1% and 92% ± 3%; group B, 93% ± 3% and 83% ± 7%; and group C, 84% ± 7% and 63% ± 14%. Use of more than one chimney subtype was associated with increased mortality (HR, 3.2; 95% CI, 1.4-7.5; P = .006).Within the PERICLES registry, use of nitinol/polyester stent graft devices with BECS during chimney endovascular aneurysm repair is associated with improved survival compared with other aortic endografts. However, this advantage was not observed for non-BECS repairs. Repairs incorporating multiple chimney subtypes were also associated with increased mortality risk. Importantly, increasing chimney stent number and bare-metal endolining stents increase chimney occlusion risk, whereas patients treated at low-volume centers have higher risk of type IA endoleak.

    View details for PubMedID 29395423

  • Septic Pulmonary Emboli From Peripheral Suppurative Thrombophlebitis: A Case Report and Literature Review. Vascular and endovascular surgery Ho, V. T., Rothenberg, K. A., McFarland, G., Tran, K., Aalami, O. O. 2018: 1538574418779469

    Abstract

    BACKGROUND: We report the case of a 90-year old woman who presented with septic pulmonary emboli due to suppurative thrombophlebitis at an old peripheral intravenous site.METHODS: After unsuccessful treatment with antibiotics, the patient was taken to the operating room for excision and drainage of the purulent superficial vein.RESULTS: We review the literature and discuss the presentation, risk factors, treatment options, and complications of this often-overlooked disease entity.CONCLUSIONS: Suppurative thrombophlebitis is a rare but morbid disease that requires a high level of clinical suspicion to diagnose.

    View details for DOI 10.1177/1538574418779469

    View details for PubMedID 29909751

  • Gender-Related Differences in Iliofemoral Arterial Anatomy among Abdominal Aortic Aneurysm Patients. Annals of vascular surgery Tran, K., Dorsey, C., Lee, J. T., Chandra, V. 2017

    Abstract

    Gender-related differences in iliofemoral anatomy are critically important for delivery of modern EVAR devices, however remains poorly characterized in the context of other patient-specific factors. The goal of the present study was to provide a detailed quantification of anatomic differences in iliofemoral anatomy between genders while controlling for height, weight, and vascular comorbidities.Fifty women with computed tomography angiograms for evaluation of abdominal aortic aneurysm between 2000 and 2012 were selected and matched to an equal nonpaired cohort of males with similar age, body mass indices (BMIs), and prevalence of vascular comorbidities (e.g., coronary artery disease, peripheral vascular disease). A 3-dimensional workstation was used to measure outer and inner diameters at anatomic reference locations at the common iliac (CIA), external iliac (EIA), and common femoral (CFA) arteries. Iliac aneurysms were excluded from analysis. Multivariate analysis-of-covariance models were employed for evaluating CIA, EIA, and CFA diameters as dependent variables.Luminal diameters were significantly smaller at the CIA (8.8 vs. 11.8 mm, P < 0.001), EIA (7.0 vs. 8.4 mm, P < 0.001), and CFA (6.7 vs. 9.5 mm, P < 0.001) arteries between men and women despite similar BMIs (27.7 vs. 27.5, P = 0.20). Similar statistically significant differences were found between men and women when comparing adventitial diameters (P < 0.001), however not when comparing degrees of stenosis (defined as outer diameter minus inner diameter [P = 0.96]). Female gender was negatively correlated with luminal diameter at the CIA (-2.34 [-3.72 to -0.96]; coef. [95% CI]), EIA (-0.95 [-1.8 to -0.04]), and CFA (-2.61 [-3.51 to -1.71]) arteries. Weight (per 10 kg) was positively correlated with luminal diameters measured at the CIA (0.41 [0.12-0.68]) and CFA (0.35 [0.16-0.53]). No independent relationships between height, vascular comorbidities, and arterial diameters were identified. 24% (n = 12) of females compared to only 14% (n = 7) of males in this study would have been ineligible for EVAR with current devices due to poor iliac access criteria.Women have significantly smaller iliofemoral arterial systems compared to men, even after controlling for height, weight, and other comorbidities that are known to affect vascular anatomy. This quantifiable difference in arterial anatomy is important to consider when deciding between various open versus endovascular treatment strategies for women.

    View details for DOI 10.1016/j.avsg.2017.01.025

    View details for PubMedID 28479440

  • Change in Aortic Neck Diameter after Endovascular Aortic Aneurysm Repair. Annals of vascular surgery Kret, M. R., Tran, K., Lee, J. T. 2017

    Abstract

    Implications of aortic neck dilatation following endovascular aneurysm repair (EVAR) are unclear. Previous studies are limited to comparisons of individual, early generation devices. We compared aortic neck dilatation among contemporary stent grafts.We reviewed preoperative and postoperative computed tomographic angiograms for EVARs performed from 2008-2014. Images were analyzed using 3-dimensional centerline reconstructions. Aortic neck diameter was measured in orthogonal planes at and 10 mm below the lowest renal artery. Device type and main body graft diameter were obtained from operative reports.Eighty-six patients were analyzed with a median radiologic follow-up of 21.9 months (range: 4-64). Stent grants implanted included 26 Cook Zenith, 26 Gore Excluder, 22 Medtronic Endurant, 10 Endologix Powerlink, and 2 Trivascular Ovation devices. Mean device oversizing was 13.6 ± 11.5% and did not vary by device type (P = 0.54). Most patients (86.0%) experienced increases in aortic neck diameter during follow-up, with a mean increase of 1.3 ± 2.2 mm (5.9 ± 9.3%) and 3.3 ± 0.6 mm (8.9 ± 2.5%) at 30 day and latest follow-up scans, respectively. Repeated-measures analysis further demonstrated a significant increase in mean neck dilatation during follow-up (P < 0.001). Neck dilatation was not significantly different across different devices (P = 0.233). However, there was a moderate positive correlation between percent change in neck diameter and degree of oversizing, which was statistically significant (rs = 0.41, P < 0.001). Type Ia endoleak was observed in 2 patients and was associated with greater mean neck dilatation (8.8 ± 3.3 mm vs. 3.35 ± 2.71, P = 0.041). There was no relationship between changes in neck diameter and sac regression/expansion.Aortic neck diameter increases consistently over time following EVAR. The degree of neck dilatation correlates with degree of device oversize but not with device type.

    View details for DOI 10.1016/j.avsg.2016.11.013

    View details for PubMedID 28341512

  • Natural history of gutter-related type Ia endoleaks after snorkel/chimney endovascular aneurysm repair. Journal of vascular surgery Ullery, B. W., Tran, K., Itoga, N. K., Dalman, R. L., Lee, J. T. 2017

    Abstract

    Alternative endovascular strategies using parallel or snorkel/chimney (chimney endovascular aneurysm repair [ch-EVAR]) techniques have been developed to address the lack of widespread availability and manufacturing limitations with branched/fenestrated aortic devices for the treatment of complex abdominal aortic aneurysms. Despite high technical success and midterm patency of snorkel stent configurations, concerns remain regarding the perceived increased incidence of early gutter-related type Ia endoleaks. We aimed to evaluate the incidence and natural history of gutter-related type Ia endoleaks following ch-EVAR.Review of medical records and available imaging studies, including completion angiography and serial computed tomographic angiography, was performed for all patients undergoing ch-EVAR at our institution between September 2009 and January 2015. Only procedures involving ≥1 renal artery with or without visceral snorkel stents were included. Primary outcomes of the study were presence and persistence or resolution of early gutter-related type Ia endoleak. Secondary outcomes included aneurysm sac shrinkage and need for secondary intervention related to the presence of type Ia gutter endoleak.Sixty patients (mean age, 75.8 ± 7.6 years; male, 70.0%) underwent ch-EVAR with a total of 111 snorkel stents (97 renal [33 bilateral renal], 12 superior mesenteric artery, 2 celiac). A mean of 1.9 ± 0.6 snorkel stents were placed per patient. Early gutter-related type Ia endoleaks were noted on 30.0% (n = 18) of initial postoperative imaging studies. Follow-up imaging revealed spontaneous resolution of these gutter endoleaks in 44.3%, 65.2%, and 88.4% of patients at 6, 12, and 18 months postprocedure, respectively. Long-term anticoagulation, degree of oversizing, stent type and diameter, and other clinical/anatomic variables were not significantly associated with presence of gutter endoleaks. Two patients (3.3%) required secondary intervention related to persistent gutter endoleak. At a mean radiologic follow-up of 20.9 months, no difference in mean aneurysm sac size change was observed between those with or without early type Ia gutter endoleak (-6.1 ± 10.0 mm vs -4.9 ± 11.5 mm; P = .23).Gutter-related type Ia endoleaks represent a relatively frequent early occurrence after ch-EVAR, but appears to resolve spontaneously in the majority of cases during early to midterm follow-up. Given that few ch-EVAR patients require reintervention related to gutter endoleaks and the presence of such endoleak did not correlate to increased risk for aneurysm sac growth, its natural history may be more benign than originally expected.

    View details for DOI 10.1016/j.jvs.2016.10.085

    View details for PubMedID 28189356

  • Classification of Chimney EVAR-Related Endoleaks: Insights From the PERICLES Registry JOURNAL OF ENDOVASCULAR THERAPY Donas, K. P., Criado, F. J., Torsello, G., Veith, F. J., Minion, D. J., PERICLES Registry Collaborators 2017; 24 (1): 72-74

    View details for DOI 10.1177/1526602816678994

    View details for Web of Science ID 000396931100010

    View details for PubMedID 27872319

  • Polar orientation of renal grafts within the proximal seal zone affects risk of early type Ia endoleaks after chimney endovascular aneurysm repair. Journal of vascular surgery Tran, K. n., Ullery, B. W., Itoga, N. n., Lee, J. T. 2017

    Abstract

    The objective of this study was to describe the polar orientation of renal chimney grafts within the proximal seal zone and to determine whether graft orientation is associated with early type Ia endoleak or renal graft compression after chimney endovascular aneurysm repair (ch-EVAR).Patients who underwent ch-EVAR with at least one renal chimney graft from 2009 to 2015 were included in this analysis. Centerline three-dimensional reconstructions were used to analyze postoperative computed tomography scans. The 12-o'clock polar position was set at the takeoff of the superior mesenteric artery. Relative polar positions of chimney grafts were recorded at the level of the renal artery ostium, at the mid-seal zone, and at the proximal edge of the graft fabric. Early type Ia endoleaks were defined as evidence of a perigraft flow channel within the proximal seal zone.There were 62 consecutive patients who underwent ch-EVAR (35 double renal, 27 single renal) for juxtarenal abdominal aortic aneurysms with a mean follow-up of 31.2 months; 18 (29%) early type Ia "gutter" endoleaks were identified. During follow-up, the majority of these (n = 13; 72%) resolved without intervention, whereas two patients required reintervention (3.3%). Estimated renal graft patency was 88.9% at 60 months. Left renal chimney grafts were most commonly at the 3-o'clock position (51.1%) at the ostium, traversing posteriorly to the 5- to 7-o'clock positions (55.5%) at the fabric edge. Right renal chimney grafts started most commonly at the 9-o'clock position (n = 17; 33.3%) and tended to traverse both anteriorly (11 to 1 o'clock; 39.2%) and posteriorly (5 to 7 o'clock; 29.4%) at the fabric edge. In the polar plane, the majority of renal chimney grafts (n = 83; 85.6%) traversed <90 degrees before reaching the proximal fabric edge. Grafts that traversed >90 degrees were independently associated with early type Ia endoleaks (odds ratio, 11.5; 95% confidence interval, 2.1-64.8) even after controlling for other device and anatomic variables. Polar orientation of the chimney grafts was not associated with graft kinking or compression (P = .38) or occlusion (P = .10). Takeoff angle of the renal arteries was the most significant predictor of chimney graft orientation. Caudally directed arteries (takeoff angle >30 degrees) were less likely to have implanted chimney grafts that traversed >90 degrees in polar angle (odds ratio, 0.09; 95% confidence interval, 0.01-0.55).Renal chimney grafts vary considerably in both starting position and their polar trajectory within the proximal seal zone. Grafts that traverse >90 degrees in polar angle within the seal zone may be at increased risk of early type Ia endoleaks and require more frequent imaging surveillance. Caudally directed renal arteries result in a more favorable polar geometry (eg, cranial-caudal orientation) with respect to endoleak risk and thus are more ideal candidates for parallel graft strategies.

    View details for PubMedID 29074111

  • Management and outcomes of symptomatic abdominal aortic aneurysms during the past 20 years National Library of Medicine Chandra, V., Trang, K., Virgin-Downey, W., Tran, K., Harris, E. J., Dalman, R. L., Lee, J. T., Mell, M. W. 2017
  • Incidence and prognostic factors related to major adverse cerebrovascular events in patients with complex aortic diseases treated by the chimney technique. Journal of vascular surgery Bosiers, M. J., Tran, K. n., Lee, J. T., Donas, K. P., Veith, F. J., Torsello, G. n., Pecoraro, F. n., Stavroulakis, K. n. 2017

    Abstract

    Endovascular aneurysm repair (EVAR) with the chimney technique (ch-EVAR) has been used for the treatment of aortic aneurysms as an alternative approach to fenestrated endografting or open repair. Nonetheless, the need for an upper extremity arterial access may contribute to a higher risk for periprocedural cerebrovascular events. This study reports on the perioperative cerebral and major adverse cardiac and cerebrovascular events (MACCE) after ch-EVAR.The PERICLES registry (PERformance of the chImney technique for the treatment of Complex aortic pathoLogiES) is an international, retrospective multicenter study evaluating the performance of ch-EVAR for the treatment of complex aortic pathologies. For the purpose of the current analysis, 425 patients treated by ch-EVAR between 2008 and 2014 were included. The primary outcome of this analysis was the incidence of procedure related cerebrovascular events defined as transient ischemic attack or stroke. The secondary end point was in-hospital MACCE, including acute coronary syndrome, stroke, and death of any cause.The incidence of clinical relevant cerebrovascular events was 1.9% (8/425). A postoperative transient ischemic attack was observed in four patients (0.95%) and a stroke in additional four (0.95%). Three patients died during the hospital stay secondary to sequelae from postoperative stroke. A prior history of stroke/transient ischemic attack, atrial fibrillation, previous carotid revascularization, or known carotid artery disease did not significantly increase the risk for adverse neurologic events. The overall MACCE rate amounted to 8.5% (36/425). Logistic regression analysis revealed that the use of bilateral upper extremity access (odds ratio [OR], 2.79; 95% confidence interval [CI], 1.04-7.45]), aneurysm rupture (OR, 5.33; 95% CI, 1.74-16.33), and a prolonged operation time (>290 minutes; OR, 1.005; 95% CI, 1.001-1.008) were associated with a significantly increased risk for MACCE.This analysis demonstrates that ch-EVAR is associated with a relatively low rate of cerebrovascular events. However, a postoperative stroke is associated with increased mortality. Ruptured aneurysms, bilateral upper extremity access as in case of multiple chimney graft placement, and longer operative times were identified as independent risk factors for MACCE.

    View details for PubMedID 29103932

  • Real-World Performance of Paclitaxel Drug-Eluting Bare Metal Stenting (Zilver PTX) for the Treatment of Femoropopliteal Occlusive Disease. Annals of vascular surgery Tran, K., Ullery, B. W., Kret, M. R., Lee, J. T. 2016

    Abstract

    The aim of this study was to evaluate the performance and predictors of stent failure of paclitaxel drug-eluting stents for the treatment of femoropopliteal disease.A retrospective review of clinical and angiographic data was performed for patients treated for femoropopliteal disease with the Zilver PTX (Cook Medical, Bloomington, IN) stent by a single operator between 2012 and 2015 at a tertiary referral center. Clinical grading was determined by both Rutherford classification and the Society for Vascular Surgery's Wound, Ischemia, and Foot Infection (WIFi) scoring system, and lesions were classified anatomically by the TransAtlantic Intersociety Consensus (TASC) II criteria. Treated lesions included those with prior in-stent restenosis and long-segment disease. Primary clinical end points were stent failure, need for reintervention, and major adverse limb events (MALE). Kaplan-Meier methods and Cox proportional hazard models were used to evaluate factors affecting outcomes.Zilver PTX stents were placed in 52 limbs among 46 patients (71.1% male, mean age 72.6 years) with a median follow-up of 11.1 (range 1-26) months. Limbs were treated for life-disabling claudication in 76.9% and critical limb ischemia in 23.1%. Disease severity was highly variable, with 21 (40.4%) limbs with TASC C or D lesions and 16 (30.7%) treated for restenosis after prior endovascular treatment. During follow-up, 6 (12.7%) limbs experienced loss of stent patency (5 occlusions, one >50% restenosis). Four limbs underwent target lesion revascularization, 2 required open bypass, 2 underwent thrombolysis, and no patients required major amputation. Primary patency was 88.9%, 81.6%, and 81.6% at 6, 12, and 18 months, respectively. Treated lesion length (hazard ratio [HR] 4.99, 95% confidence interval [CI] 1.14-21.75) was the only independent predictor of patency loss. Freedom from target lesion revascularization at 6, 12, and 18 months was 94.2%, 87.8%, and 87.8%, respectively. Freedom from MALE (composite of thrombolysis, major amputation, and bypass operation) was 97.5%, 90.9%, and 79.6% at 6, 12, and 18 months, respectively. Chronic renal insufficiency was the only factor that trended toward increased risk of MALE (HR 9.92, 95% CI 0.86-113.35) within a multivariate model.Our real-world experience supports the continued use of the Zilver PTX for the treatment of both de novo lesions and lesions with prior endovascular revascularization in the femoropopliteal segment. Routine follow-up between 6 and 12 months postoperatively is essential for detecting early restenosis and guiding reintervention. Careful attention when treating complex lesions and long-segment disease remains important for selecting the optimal revascularization strategy for individual patients and optimizing stent patency.

    View details for DOI 10.1016/j.avsg.2016.08.006

    View details for PubMedID 27554688

  • Renal function changes after fenestrated endovascular aneurysm repair JOURNAL OF VASCULAR SURGERY Kenneth Tran, K., Fajardo, A., Ullery, B. W., Goltz, C., Lee, J. T. 2016; 64 (2): 273-280

    Abstract

    Limited data exist regarding the effect of fenestrated endovascular aneurysm repair (fEVAR) on renal function. We performed a comprehensive analysis of acute and chronic renal function changes in patients after fEVAR.This study included patients undergoing fEVAR at two institutions between September 2012 and March 2015. Glomerular filtration rate was estimated using the Modification of Diet in Renal Disease formula with serum creatinine levels obtained during the study period. Acute and chronic renal dysfunction was assessed using the RIFLE (Risk, Injury, Failure, Loss, End-stage renal disease) criteria and the chronic kidney disease (CKD) staging system, respectively.fEVAR was performed in 110 patients for juxtarenal or paravisceral aortic aneurysms, with a mean follow-up of 11.7 months. A total of 206 renal stents were placed, with a mean aneurysm size of 62.9 mm (range, 45-105 mm) and a mean neck length of 4.1 mm. Primary renal stent patency was 97.1% at the latest follow-up. Moderate kidney disease (CKD stage ≥ 3) was present in 51% of patients at baseline, with a mean preoperative glomerular filtration rate of 60.0 ± 19.6 mL/min/1.73 m(2). Acute kidney injury occurred in 25 patients (22.7%), although 15 of these (60%) were classified as having mild dysfunction. During follow-up, 59 patients (73.7%) were found to have no change or improved renal disease by CKD staging, and 19 (23.7%) had a CKD increase of one stage. Two patients were noted to have end-stage renal failure requiring hemodialysis. Clinically significant renal dysfunction was noted in 21 patients (26.2%) at the latest follow-up. Freedom from renal decline at 1 year was 76.1% (95% confidence interval, 63.2%-85.0%). Surrogate markers for higher operative complexity, including operating time (P = .001), fluoroscopy time (P < .001), contrast volume (P = .017), and blood loss (P = .002), served as dependent risk factors for acute kidney injury, although though no independent predictors were identified. Age (P = .008) was an independent risk factor for long-term decline, whereas paradoxically, baseline kidney disease (P = .032) and longer operative times (P = .014) were protective of future renal dysfunction.Acute and chronic renal dysfunction both occur in approximately one-quarter of patients after fEVAR; however, most of these cases are classified as mild according to consensus definitions of renal injury. The presence of mild or moderate baseline kidney disease should not preclude endovascular repair in the juxtarenal population. Routine biochemical analysis and branch vessel surveillance remain important aspects of clinical follow-up for patients undergoing fEVAR.

    View details for DOI 10.1016/j.jvs.2016.01.041

    View details for PubMedID 27237402

  • Sustained Late Branch Patency and Low Incidence of Persistent Type Ia Endoleaks Following Snorkel/chimney EVAR Shown in the Updated PERICLES Registry Lee, J. T., Pecoraro, F., Dalman, R. L., Tran, K., Torsello, G., Veith, F. J., Lachat, M., Donas, K. P. MOSBY-ELSEVIER. 2016: 145S
  • Snorkel/Chimney Stent Morphology Predicts Renal Dysfunction after Complex Endovascular Aneurysm Repair ANNALS OF VASCULAR SURGERY Tran, K., Ullery, B. W., Lee, J. T. 2016; 30: 1-11

    Abstract

    Despite the high technical success and midterm patency of snorkel stents, concerns remain about structural durability and its effect on long-term renal function. We sought to evaluate the luminal stability of renal snorkel stents to investigate morphologic predictive factors of renal dysfunction after snorkel/chimney endovascular aneurysm repair (sn-EVAR).Patients with high quality computer tomography angiography after sn-EVAR between 2009 and 2013 were included for analysis. Luminal diameters of renal snorkel stents were measured on a 3-dimensional workstation at the proximal, main-body junction, and distal locations. Creatinine values and estimated glomerular filtration rates (eGFR) were recorded throughout the preoperative, perioperative, and postoperative course. Acute kidney injury (AKI) and chronic renal decline were evaluated using the risk, injury, failure, loss of function, end stage renal disease (RIFLE) criteria and chronic kidney disease (CKD) staging system, respectively.52 patients underwent sn-EVAR (33 double renal, 19 single renal) with a 2-year primary patency of 95% at a mean follow-up of 21 months, of which 34 had suitable imaging protocols. In this subset, snorkel stents had mean deformations of -0.14 ± 0.52 (2.8%), -0.23 ± 0.52 (4.6%) and -0.04 ± 0.16 mm (1.8%) at the proximal, junction, and distal segments. Four cases of significant >50% stent collapse occurred during follow-up, all of which occurred at the junctional segment. In the total cohort, 17 (32.6%) and 16 (30.7%) patients developed AKI and chronic renal decline, respectively. Multivariate regression identified larger proximal luminal diameters at latest follow-up (odds ratio 0.67; confidence interval [CI] 0.006-0.740; P = 0.037) as the only protective morphologic risk factor for developing chronic renal decline. No independent predictor factors for AKI were found. Rates of renal decline were significantly worse with smaller measured proximal lumens with a 1-year freedom from renal decline of 50% vs. 77-83% for diameters measured less than 4 mm vs. greater than 4 mm (P = 0.010). Degree of oversizing also affected rates of decline with greater oversizing associated with improved freedom from renal decline at 1 year of 100% vs. 57% (P = 0.012). Using a multivariate Cox model, stent oversizing (hazard ratio [HR], 0.039; P = 0.018) and baseline CKD (HR 0.033, P = 0.004) were the only independent factors, both of which resulted in slower rates of renal decline during follow-up.Renal snorkel stent grafts maintain a high degree of patency and luminal stability at 2-year follow-up. However, stent collapse remains a rare but concerning risk, with the junctional segment most prone to significant stent deformation. Renal snorkel stents must be critically sized relative to native renal anatomy, and we recommend using at least stents sized ≥6 mm to minimize the risk of renal dysfunction. Frequent and regular radiographic and laboratory follow-up remains important as we further optimize the approach to complex EVAR.

    View details for DOI 10.1016/j.avsg.2015.04.093

    View details for Web of Science ID 000367408700001

  • Use of a proactive duplex ultrasound protocol for hemodialysis access. J Vasc Surg Itoga, N., Ullery , B., Tran, K. 2016
  • Collected World Experience About the Performance of the Snorkel/Chimney Endovascular Technique in the Treatment of Complex Aortic Pathologies The PERICLES Registry ANNALS OF SURGERY Donas, K. P., Lee, J. T., Lachat, M., Torsello, G., Veith, F. J. 2015; 262 (3): 546-553

    Abstract

    We sought to analyze the collected worldwide experience with use of snorkel/chimney endovascular aneurysm repair (EVAR) for complex abdominal aneurysm treatment.EVAR has largely replaced open surgery worldwide for anatomically suitable aortic aneurysms. Lack of availability of fenestrated and branched devices has encouraged an alternative strategy utilizing parallel or snorkel/chimney grafts (ch-EVAR).Clinical and radiographic information was retrospectively reviewed and analyzed on 517 patients treated by ch-EVAR from 2008 from 2014 by prearranged defined and documented protocols.A total of 119 patients in US centers and 398 in European centers were treated during the study period. US centers preferentially used Zenith stent-grafts (54.2%) and European centers Endurant stent-grafts (62.2%) for the main body component. Overall 898 chimney grafts (49.2% balloon expandable, 39.6% self-expanding covered stents, and 11.2% balloon expandable bare metal stents) were placed in 692 renal arteries, 156 superior mesenteric arteries (SMA), and 50 celiac arteries. At a mean follow-up of 17.1 months (range: 1-70 months), primary patency was 94%, with secondary patency of 95.3%. Overall survival of patients in this high-risk cohort for open repair at latest follow-up was 79%.This global experience represents the largest series in the ch-EVAR literature and demonstrates comparable outcomes to those in published reports of branched/fenestrated devices, suggesting the appropriateness of broader applicability and the need for continued careful surveillance. These results support ch-EVAR as a valid off-the-shelf and immediately available alternative in the treatment of complex abdominal EVAR and provide impetus for the standardization of these techniques in the future.

    View details for DOI 10.1097/SLA.0000000000001405

    View details for PubMedID 26258324

  • Safety and efficacy of antiplatelet/anticoagulation regimens after Viabahn stent graft treatment for femoropopliteal occlusive disease. Journal of vascular surgery Ullery, B. W., Tran, K., Itoga, N., Casey, K., Dalman, R. L., Lee, J. T. 2015; 61 (6): 1479-1488

    Abstract

    We aimed to determine the safety and efficacy of antiplatelet/anticoagulation regimens after placement of Viabahn stent graft (W. L. Gore & Associates, Flagstaff, Ariz) for the treatment of femoropopliteal occlusive disease.Clinical, angiographic, and procedural data for patients undergoing endovascular treatment of femoropopliteal occlusive disease using Viabahn covered stent grafts at a single institution between 2006 and 2013 were retrospectively reviewed. Graft patency and freedom from thrombolysis, major adverse limb event, and reintervention were determined by Kaplan-Meier analysis. The influence of relevant variables on clinical outcome was determined through univariate and multivariate Cox proportional hazards analyses.Viabahn stent grafts were placed in a total of 91 limbs in 61 patients (66% men; mean age, 69 ± 12 years) during the study period. Indication for intervention was either claudication (n = 59) or critical limb ischemia (n = 32), with the majority (70%) classified as TransAtlantic Inter-Society Consensus II C (n = 33) or D (n = 31) lesions. Mean follow-up was 38.3 months (range, 1-91 months). Postprocedural pharmacologic regimens included aspirin, clopidogrel, and warfarin (47%); indefinite aspirin and clopidogrel (46%); or aspirin and temporary clopidogrel (7%). Primary and secondary patency rates were 60%, 44%, and 36% and 95%, 82%, and 74% at 1 year, 3 years, and 5 years, respectively. Kaplan-Meier analysis demonstrated more aggressive antiplatelet/anticoagulation regimens to be associated with improved primary patency and freedom from reintervention. Cox proportional hazards analysis demonstrated TransAtlantic Inter-Society Consensus II D lesions, tobacco use, coronary artery disease, and smaller stent diameter to be independent risk factors for stent graft failure. Bleeding events were limited to those in the aspirin, clopidogrel, and warfarin group (11.6% [n = 5]; P = .052), although the majority of these events were not life-threatening, and only two cases required blood transfusion.Increasingly aggressive antithrombotic regimens after Viabahn stent graft placement trended toward improved overall clinical outcomes, although the marginal patency benefit observed with the addition of warfarin to dual antiplatelet therapy was tempered by an observed increased risk of bleeding complications. Longer term follow-up and multicenter studies are needed to further define optimal type and duration of antithrombotic therapy after endovascular peripheral interventions.

    View details for DOI 10.1016/j.jvs.2014.12.062

    View details for PubMedID 25704407

  • Renal function changes after snorkel/chimney repair of juxtarenal aneurysms. Journal of vascular surgery Lee, J. T., Varu, V. N., Tran, K., Dalman, R. L. 2014; 60 (3): 563-570

    Abstract

    The snorkel approach for endovascular aneurysm repair (EVAR) has been found to be a safe and viable alternative to open repair for juxtarenal abdominal aortic aneurysms with good short-term outcomes. Concerns about long-term durability and renal branch patency with this technique have been raised with the increasing availability of fenestrated devices. We sought to evaluate renal function changes in patients undergoing "snorkel" EVAR (sn-EVAR).Patients who underwent sn-EVAR from 2009 to 2012 were included in this analysis. Creatinine values were obtained throughout the patient's preoperative, perioperative, and postoperative course. Glomerular filtration rate (GFR) was estimated by the simplified Modification of Diet in Renal Disease formula. Acute renal dysfunction was analyzed according to the RIFLE (Risk, Injury, Failure, Loss, End stage) criteria, whereas chronic renal dysfunction was stratified by the chronic kidney disease staging system.Forty-three consecutive patients underwent sn-EVAR (31 double renal, 12 single renal) for juxtarenal aortic aneurysms. Mean follow-up time was 21 months. Mean aneurysm size was 6.6 cm (range, 5.1-10.5 cm) with anatomy not suitable for treatment with standard EVAR (mean neck length, 1.6 mm); 74 renal snorkel stents were placed in these patients with a 2-year primary patency of 95%. On average, the cohort at baseline was stratified as having moderate renal dysfunction. Mean baseline, maximum postoperative, and latest follow-up creatinine concentrations were 1.20, 1.49, and 1.43, respectively (P = .004). Mean baseline, maximum postoperative, and latest follow-up GFRs were 57.4, 47.8, and 49.2, respectively (P = .014). With use of RIFLE criteria, 14 patients (32.6%) experienced some form of acute kidney injury, although 10 of these patients (23.3%) were classified as mild (25%-50% decline in GFR). On analysis without the RIFLE criteria, 21.4% of patients had postoperative creatinine concentration >1.5 mg/dL, 28.6% had postoperative creatinine concentration increase >30%, and 28.6% had postoperative GFR decline >30%. For the entire study cohort at latest follow-up, 51% experienced no decline of chronic renal dysfunction and 8.1% had improvement in renal function. Renal function declined by one stage in 35.2% of the cohort and by two stages in 5.4%. On analysis without chronic kidney disease staging, 24.3% of patients had latest follow-up creatinine concentration >1.5 mg/dL, 29.7% had latest follow-up creatinine concentration increase >30%, and 24.3% had latest follow-up GFR decline >30%. Mean survival time from significant renal decline was 23.4 months.sn-EVAR continues to demonstrate a high rate of technical success and results in only mild rates of acute and midterm renal function decline according to a number of established definitions for renal dysfunction. Continued monitoring of renal function, renal stent behavior, and abdominal aortic aneurysm sac changes remains critically important in the long-term management of patients undergoing sn-EVAR, particularly given the high comorbidities associated with juxtarenal aortic aneurysms.

    View details for DOI 10.1016/j.jvs.2014.03.239

    View details for PubMedID 24785683

  • Construction of an Inexpensive, Hand-Held Fundus Camera through Modification of a Consumer "Point-and-Shoot" Camera INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE Tran, K., Mendel, T. A., Holbrook, K. L., Yates, P. A. 2012; 53 (12): 7600-7607

    Abstract

    To construct a low-cost, easy-to-use, high-image-quality mydriatic fundus camera with "point-and-shoot" operation, and to evaluate the efficacy of this camera to accurately document retinal disease.A prototype portable fundus camera was designed by interfacing a novel optical module with a Panasonic Lumix G2 consumer camera. Low-cost, commercially available optics were used to create even illumination of the fundus, providing a 50° retinal field of view. A comparative study assessing the image quality of the prototype camera against a traditional tabletop fundus camera was conducted under an Institutional Review Board (IRB)-approved study.A stand-alone, mydriatic camera prototype was successfully developed at a parts cost of less than $1000. The prototype camera was capable of operating in a point-and-shoot manner with automated image focusing and exposure, and the image quality of fundus photos was comparable to that of existing commercial cameras. Pathology related to both nonproliferative and proliferative diabetic retinopathy and age-related macular degeneration was easily identified from fundus images obtained from the low-cost camera.Early prototype development and clinical testing have shown that a consumer digital camera can be inexpensively modified to image the fundus with professional diagnostic quality. The combination of low cost, portability, point-and-shoot operation, and high image quality provides a foundational platform on which one can design an accessible fundus camera to screen for eye disease.

    View details for DOI 10.1167/iovs.12-10449

    View details for Web of Science ID 000313053500023

    View details for PubMedID 23049089

    View details for PubMedCentralID PMC3495602