Academic Appointments

All Publications

  • Surgical management of severe mitral annular calcification. Asian cardiovascular & thoracic annals Elde, S., Zhu, Y., MacArthur, J. W., Woo, Y. J. 2022: 2184923221136935


    BACKGROUND: Surgical management of severe mitral annular calcification (MAC) presents a challenging problem for even the most experienced surgeons. Preoperative planning is the most effective strategy to mitigate risk in these scenarios. MAC alone should not disqualify a patient from consideration for mitral valve repair, although the presence of concurrent greater than moderate stenosis warrants consideration of mitral valve replacement.METHODS: While repair and replacement techniques for mitral regurgitation in the setting of MAC overlap with those used to repair a non-calcified mitral apparatus, there are unique considerations to the surgical conduct of these procedures. Specifically, this article describes techniques that may be employed when the severity of MAC precludes typical repair or replacement strategies.RESULTS: Between 2014 and 2021, 77 patients were operated on by a single surgeon for mitral valve disease complicated by severe MAC. Using the systematic approach described herein, 1-year mortality was 7.8% and overall mortality over a follow-up period extending 1 to 8 years was 9.1%.CONCLUSIONS: Despite the inherent challenges of mitral valve repair or replacement in the setting of severe MAC, a systematic approach beginning with preoperative planning, modification of annular suture placement, and techniques to mitigate severe complications have, in our experience, resulting in a reliable methodology for managing severe MAC with excellent outcomes.

    View details for DOI 10.1177/02184923221136935

    View details for PubMedID 36537728

  • Outcomes of Heart Transplantation Using a Temperature-controlled Hypothermic Storage System. Transplantation Zhu, Y., Shudo, Y., He, H., Kim, J. Y., Elde, S., Williams, K. M., Walsh, S. K., Koyano, T. K., Guenthart, B., Woo, Y. J. 2022


    The SherpaPak Cardiac Transport System is a novel technology that provides stable, optimal hypothermic control during organ transport. The objectives of this study were to describe our experience using the SherpaPak system and to compare outcomes after heart transplantation after using SherpaPak versus the conventional static cold storage method (non-SherpaPak).From 2018 to June 2021, 62 SherpaPak and 186 non-SherpaPak patients underwent primary heart transplantation at Stanford University with follow-up through May 2022. The primary end point was all-cause mortality, and secondary end points were postoperative complications. Optimal variable ratio matching, cox proportional hazards regression model, and Kaplan-Meier survival analyses were performed.Before matching, the SherpaPak versus non-SherpaPak patients were older and received organs with significantly longer total allograft ischemic time. After matching, SherpaPak patients required fewer units of blood product for perioperative transfusion compared with non-SherpaPak patients but otherwise had similar postoperative outcomes such as hospital length of stay, primary graft dysfunction, inotrope score, mechanical circulatory support use, cerebral vascular accident, myocardial infarction, respiratory failure, new renal failure requiring dialysis, postoperative bleeding or tamponade requiring reoperation, infection, and survival.In conclusion, this is one of the first retrospective comparison studies that evaluated the outcomes of heart transplantation using organs preserved and transported via the SherpaPak system. Given the excellent outcomes, despite prolonged total allograft ischemic time, it may be reasonable to adopt the SherpaPak system to accept organs from a remote location to further expand the donor pool.

    View details for DOI 10.1097/TP.0000000000004416

    View details for PubMedID 36510359

  • Type A Aortic Dissection With Concurrent Aortic Valve Endocarditis, Subarachnoid Hemorrhage, and Disseminated Intravascular Coagulation. JACC. Case reports Elde, S. F., Guenthart, B. A., de Biasi, A., Dalal, A. R., Casselman, K. G., Hiesinger, W., Burton, E. C. 2022; 4 (14): 839-843


    We describe surgical repair of a Stanford Type A aortic dissection with concurrent aortic valve Streptococcus equi endocarditis in the setting of subarachnoid hemorrhage and disseminated intravascular coagulation. Multidisciplinary collaboration among specialists from a variety of disciplines is essential when treating acutely ill cardiovascular patients with multisystem involvement. (Level of Difficulty: Beginner.).

    View details for DOI 10.1016/j.jaccas.2021.05.008

    View details for PubMedID 35912321

  • An automated line-clearing chest tube system after cardiac surgery. JTCVS open Obafemi, O. O., Wang, H., Bajaj, S. S., O'Donnell, C. T., Elde, S., Boyd, J. H. 2022; 10: 246-253


    To complete the first in-human study of the automated line clearance Thoraguard chest tube system. The study focuses on the viability and efficacy of the device in comparison with conventional models as well as secondary matters such as patient experience and ease of use.This was a single-center, prospective, open-label study involving adult patients (n = 27) who underwent nonemergent, first-time, cardiac surgery. Patients received automated clearance chest tubes for surgical drainage in both the mediastinal and pleural spaces. The control group was retrospective (n = 80); individuals received conventional chest tubes placed and secured in locations determined at the surgeon's discretion.The automated-clearance tubes exhibited a similar drainage profile at 1, 3, 6, 12, and 24 hours compared with the conventional chest tubes. The final output at the time of tube removal was also similar (1150 [750-1590] vs 1289 [766.3-1890] mL, respectively, P = .76). The number of patients readmitted for drainage of an effusion was similar in both groups (1/27 [3.7%] vs 3/80 [3.75%], P > .99).This study has shown that the Centese Thoraguard chest tube system is a viable option for surgical chest drainage and effective when used in routine cardiac surgery operations.

    View details for DOI 10.1016/j.xjon.2022.02.020

    View details for PubMedID 36004272

    View details for PubMedCentralID PMC9390781

  • Exvivo aortic valve replacement before orthotopic heart transplantation. JTCVS techniques Elde, S. F., Guenthart, B. A., Shudo, Y., Woo, Y. J. 2022; 12: 118-120

    View details for DOI 10.1016/j.xjtc.2022.01.008

    View details for PubMedID 35403016

  • Electrophysiologic Conservation of Epicardial Conduction Dynamics After Myocardial Infarction and Natural Heart Regeneration in Newborn Piglets. Frontiers in cardiovascular medicine Wang, H., Pong, T., Obafemi, O. O., Lucian, H. J., Aparicio-Valenzuela, J., Tran, N. A., Mullis, D. M., Elde, S., Tada, Y., Baker, S. W., Wang, C. Y., Cyr, K. J., Paulsen, M. J., Zhu, Y., Lee, A. M., Woo, Y. J. 2022; 9: 829546


    Newborn mammals, including piglets, exhibit natural heart regeneration after myocardial infarction (MI) on postnatal day 1 (P1), but this ability is lost by postnatal day 7 (P7). The electrophysiologic properties of this naturally regenerated myocardium have not been examined. We hypothesized that epicardial conduction is preserved after P1 MI in piglets. Yorkshire-Landrace piglets underwent left anterior descending coronary artery ligation at age P1 (n = 6) or P7 (n = 7), After 7 weeks, cardiac magnetic resonance imaging was performed with late gadolinium enhancement for analysis of fibrosis. Epicardial conduction mapping was performed using custom 3D-printed high-resolution mapping arrays. Age- and weight-matched healthy pigs served as controls (n = 6). At the study endpoint, left ventricular (LV) ejection fraction was similar for controls and P1 pigs (46.4 ± 3.0% vs. 40.3 ± 4.9%, p = 0.132), but significantly depressed for P7 pigs (30.2 ± 6.6%, p < 0.001 vs. control). The percentage of LV myocardial volume consisting of fibrotic scar was 1.0 ± 0.4% in controls, 9.9 ± 4.4% in P1 pigs (p = 0.002 vs. control), and 17.3 ± 4.6% in P7 pigs (p < 0.001 vs. control, p = 0.007 vs. P1). Isochrone activation maps and apex activation time were similar between controls and P1 pigs (9.4 ± 1.6 vs. 7.8 ± 0.9 ms, p = 0.649), but significantly prolonged in P7 pigs (21.3 ± 5.1 ms, p < 0.001 vs. control, p < 0.001 vs. P1). Conduction velocity was similar between controls and P1 pigs (1.0 ± 0.2 vs. 1.1 ± 0.4 mm/ms, p = 0.852), but slower in P7 pigs (0.7 ± 0.2 mm/ms, p = 0.129 vs. control, p = 0.052 vs. P1). Overall, our data suggest that epicardial conduction dynamics are conserved in the setting of natural heart regeneration in piglets after P1 MI.

    View details for DOI 10.3389/fcvm.2022.829546

    View details for PubMedID 35355973

  • Analysis of the revised heart allocation policy and the influence of increased mechanical circulatory support on survival. The Journal of thoracic and cardiovascular surgery Elde, S., He, H., Lingala, B., Baiocchi, M., Wang, H., Hiesinger, W., MacArthur, J. W., Shudo, Y., Woo, Y. J. 1800


    OBJECTIVES: In 2018, the new United Network for Organ Sharing heart allocation policy took effect. This study evaluated waitlist mortality, mechanical circulatory support utilization, and its influence on posttransplant survival.METHODS: Two 12-month cohorts matched for time of year before and after the policy change were defined by inclusion criteria of first-time transplant recipients aged 18years or older who were listed and underwent transplant during the same era. Student t test and Wilcoxon rank-sum test were used for mean and median differences, respectively. Categorical variables were compared using chi2 or Fisher exact test. Kaplan-Meier curves were used to characterize survival, including time-to-event analysis with the log-rank test. Fine-Gray modeling was used to characterize waitlist mortality. Cox proportional-hazard models were used for multivariate analysis.RESULTS: Waitlist mortality in the new era is significantly improved based on a competing-risks model (Gray test P=.0064). Unadjusted 180-day posttransplant mortality increased from 5.8% during the old era to 8.0% during the new (P=.0134). However, time-to-event analysis showed similar 180-day survival in both eras. After risk adjustment, the hazard ratio for posttransplant 180-day mortality during the new era was 1.18 (95% CI, 0.85-1.64; P=.333). The posttransplant 180-day mortality of the extracorporeal membrane oxygenation bridge-to-transplant subgroup improved from 28.6% in the old era to 8.4% in the new era (P=.0103; log-rank P=.0021). Patients with an intra-aortic balloon pump at the time of transplant had similar 180-day posttransplant mortality between eras (5.4% vs 7.0%; P=.4831).CONCLUSIONS: The United Network for Organ Sharing policy change is associated with reduced waitlist mortality and similar risk adjusted posttransplant 180-day mortality. The new era is also associated with improved 180-day survival in patientsundergoing bridge to transplant with extracorporeal membrane oxygenation.

    View details for DOI 10.1016/j.jtcvs.2021.11.076

    View details for PubMedID 35027214

  • Extracorporeal Membrane Oxygenation Bridge to Heart-Lung Transplantation. ASAIO journal (American Society for Artificial Internal Organs : 1992) Shudo, Y., Elde, S., Lingala, B., He, H., Casselman, K. G., Zhu, Y., Kasinpila, P., Woo, Y. J. 2021

    View details for DOI 10.1097/MAT.0000000000001457

    View details for PubMedID 34843181

  • Operative Technique of Donor Organ Procurement for En Bloc Heart-Liver Transplantation. Transplantation Elde, S. n., Brubaker, A. L., Than, P. A., Rinewalt, D. n., MacArthur, J. W., Alassar, A. n., Bonham, C. A., Esquivel, C. O., Shudo, Y. n., Concepcion, W. n., Woo, Y. J. 2021


    Combined heart-liver transplant is an emerging option for patients with indications for heart transplantation and otherwise prohibitive hepatic dysfunction. Heart-liver transplantation is particularly relevant for patients with single ventricle physiology who often develop Fontan-associated liver disease and fibrosis. While only performed at a limited number of centers, several approaches to combined heart-liver transplantation have been described. The en bloc technique offers several potential advantages over the traditional sequential technique. Specifically, en bloc heart-liver transplantation may allow improved hemodynamics, decreased bleeding, reduced liver allograft ischemic time, and may result in reduced rates of graft dysfunction. Here we describe our center's en bloc heart-liver procurement technique in detail, with the aim of allowing broader use and standardization of this technique. Supplemental Visual Abstract;

    View details for DOI 10.1097/TP.0000000000003697

    View details for PubMedID 33606485

  • The Expanding Armamentarium of Innovative Bioengineered Strategies to Augment Cardiovascular Repair and Regeneration Frontiers in Bioengineering and Biotechnology Elde, S., Wang, H., Woo, Y. 2021: 674172


    Cardiovascular disease remains the leading cause of death worldwide. While clinical trials of cell therapy have demonstrated largely neutral results, recent investigations into the mechanisms of natural myocardial regeneration have demonstrated promising new intersections between molecular, cellular, tissue, biomaterial, and biomechanical engineering solutions. New insight into the crucial role of inflammation in natural regenerative processes may explain why previous efforts have yielded only modest degrees of regeneration. Furthermore, the new understanding of the interdependent relationship of inflammation and myocardial regeneration have catalyzed the emergence of promising new areas of investigation at the intersection of many fields.

    View details for DOI 10.3389/fbioe.2021.674172

    View details for PubMedCentralID PMC8205517

  • Navigating the Crossroads of Cell Therapy and Natural Heart Regeneration Frontiers in Cell and Developmental Biology Elde, S., Wang, H., Woo, Y. 2021: 674180


    Cardiovascular disease remains the leading cause of death worldwide despite significant advances in our understanding of the disease and its treatment. Consequently, the therapeutic potential of cell therapy and induction of natural myocardial regeneration have stimulated a recent surge of research and clinical trials aimed at addressing this challenge. Recent developments in the field have shed new light on the intricate relationship between inflammation and natural regeneration, an intersection that warrants further investigation.

    View details for DOI 10.3389/fcell.2021.674180

    View details for PubMedCentralID PMC8148343

  • Extracorporeal Membrane Oxygenation Bridge to Heart-Lung Transplantation ASAIO Shudo, Y., Elde, S., Lingala, B., He, H., Casselman, K. G., Zhu, Y., Kasinpila, P., Woo, Y. 2021
  • A Novel Alternative to The Commando Procedure: Constructing a Neo-Aortic Root by Anchoring to the Sewing Ring of the Replaced Mitral Valve. JTCVS techniques Elde, S., de Biasi, A., Woo, Y. J., Burton, E. 2020

    View details for DOI 10.1016/j.xjtc.2020.08.037

    View details for PubMedID 32875308

  • The Thoracic Surgery Social Media Network Experience During the COVID-19 Pandemic. The Annals of thoracic surgery Luc, J. G., Archer, M. A., Arora, R. C., Bender, E. M., Blitz, A., Cooke, D. T., Elde, S., Guy, T. S., Halpern, A. L., Harrington, C., Hlci, T. N., Kidane, B., Olive, J. K., Ouzounian, M., Stamp, N., Vervoort, D., Varghese, T. K., Antonoff, M. B. 2020

    View details for DOI 10.1016/j.athoracsur.2020.05.006

    View details for PubMedID 32425205

  • The Impact of Donor Gender on Heart Transplantation Outcomes - A Study of over 60,000 Patients in the United States Zhu, Y., Shudo, Y., Lingala, B., Elde, S., Woo, Y. ELSEVIER SCIENCE INC. 2020: S42
  • Racial and Sex Disparities Persist in Modern Cardiac Surgical Outcomes. Annals of surgery Elde, S. F., Woo, Y. J. 2020; 272 (4): 668

    View details for DOI 10.1097/SLA.0000000000004333

    View details for PubMedID 32932323

  • Transplantation Outcomes in Adults With Congenital Heart Disease Have Room to Grow. The Canadian journal of cardiology Elde, S. n., Woo, Y. J. 2019

    View details for DOI 10.1016/j.cjca.2019.11.016

    View details for PubMedID 32046908

  • Tailored Approach to Surgical Exposure Reduces Surgical Site Complications after Bilateral Lung Transplantation SURGICAL INFECTIONS Elde, S., Huddleston, S., Jackson, S., Kelly, R., Shumway, S., Loor, G. 2017; 18 (8): 929-935


    We evaluated the effects of tailoring the operative approach on major surgical site complications and outcomes in lung transplant recipients.Beginning in July 2013, bilateral lung transplants at a single institution were performed either through sternotomy or clamshell depending on proximity of hilar structures by computed tomography (CT), anticipated complexity, past surgical history, and surgeon experience. Patient demographics and outcomes were collected in the institution's Transplant Information Services (TIS). A major surgical site complication was defined as a sterile or infected incision requiring operative intervention.One hundred six bilateral lung transplants (68 via clamshell and 38 via median sternotomy) were performed between July 2013 and June 2016. Median sternotomy patients were older (mean age 55 vs. 50 y, p = 0.04), and less likely to have cystic fibrosis (5 [13%] vs. 19 [28%], p = 0.21) or diabetes (5 [13%] vs. 26 [38%], p = 0.01). There was no statistically significant difference in mean lung allocation score (LAS) (45 vs. 48, p = 0.39) and body mass index (BMI; kg/m2; 25.3 vs. 24.4, p = 0.29) between the sternotomy and clamshell group. Fifteen (14.2%) patients experienced a total of 25 surgical site complications (19 major and 6 minor). No sternotomy patient had a major surgical site complication and 11 (16.2%) clamshell patients had a major surgical site complication (p = 0.01). Of these 11 patients, 5 (45%) required multiple operative revisions related to the surgical site. Freedom from major surgical site complications at three years was 100% for sternotomy patients and 80% for clamshell patients (p = 0.017).Tailoring the operative approach can reduce surgical site complications in lung transplant patients by avoiding a clamshell whenever feasible.

    View details for DOI 10.1089/sur.2017.144

    View details for Web of Science ID 000414908600014

    View details for PubMedID 29053438