Institute Affiliations

Professional Education

  • MD, Albany Medical College of Union University (2018)
  • MPH, University of Illinois at Urbana-Champaign (2014)
  • BS, University of Illinois at Urbana-Champaign (2014)


  • Krishna Martinez-Singh; Krishna Rocha-Singh. "United States: Apparatus and method for promoting angiogenesis in ischemic tissue", Sep 4, 2018

All Publications

  • Analysis of Medicare Payments and Patient Outcomes with Pre-Operative Imaging for Carotid Endarterectomy. Annals of vascular surgery Itoga, N. K., Martinez-Singh, K., Lee, J. T., John Harris, E., Baker, L. C., Garcia-Toca, M. 2021


    OBJECTIVE: The use of radiographic evaluation of carotid disease may vary, and current guidelines do not strongly recommend the use of cross-sectional imaging (CSI) prior to surgical intervention. We sought to describe the trends in pre-operative carotid imaging and evaluate the associated clinical outcomes and Medicare payments for patients undergoing carotid endarterectomy (CEA) for asymptomatic carotid disease.METHODS: We used a 20% Medicare sample from 2006-2014 identifying patients undergoing CEA for asymptomatic disease. We evaluated pre-operative carotid ultrasound and CSI use: CT or MRI of the neck prior to CEA. We calculated average payments of each study from the carrier file and revenue center file. Imaging payments included both the professional component (PC) and the technical component (TC). Claims with a reimbursement of $0 and studies where payment for both the TC and PC could not be identified were excluded from the overall calculation to determine average payment per study. Inpatient reimbursements according to DRG 37-39 were calculated. We compared hospital length of stay (LOS), in hospital stroke, carotid re-exploration, and mortality according to CSI use.RESULTS: A total of 58,993 CEAs were identified with pre-operative carotid imaging. The average age was 74.8±7.5 years, and 56.0% were men. A total of 19,678 (33%) patients had ultrasound alone with an average of (2.4±1.9) exams prior to CEA. A total of 39,315 patients underwent CSI prior to CEA with 2.5±2.1 ultrasounds, 0.95±0.86 neck CTs and 0.47±0.7 MRIs per patient. The average payment for ultrasound was $140±40, $282±94 for CT and $410±146 for MRI. The average inpatient reimbursements were $7,413±4,215 for patients without CSI compared with $7,792±3,921 for patients with CSI, P<.001. The average LOS during CEA admission was 2.5±3.7days. Patients with CSI had a slightly lower percentage of patients being discharged by post-operative day two compared with ultrasound alone (88.9% vs. 91.5%, respectively, P<.001). The overall in-hospital stroke rate was 0.38% and carotid re-exploration rate was 1.0% and there was no statistical significant difference between groups. Median follow-up was 3.9 years, and mortality at 8 years was 50% and did not statistically differ between groups.CONCLUSIONS: Our analysis found pre-operative imaging to include CSI in nearly two-thirds of patients prior to CEA for asymptomatic disease. As imaging and inpatient payments were higher with patients with CSI further work is needed to understand when CSI is appropriate prior to surgical intervention to appropriately allocate healthcare resources.

    View details for DOI 10.1016/j.avsg.2021.06.001

    View details for PubMedID 34153493

  • Analysis of Medicare Payments for Preoperative Imaging Before Carotid Endarterectomy Itoga, N. K., Martinez-Singh, K., Harris, J., Lee, J. T., Baker, L., Garcia-Toca, M. MOSBY-ELSEVIER. 2020: E17–E18
  • Increased vertebral exposure in anterior lumbar interbody fusion associated with venous injury and deep venous thrombosis. Journal of vascular surgery. Venous and lymphatic disorders Ho, V. T., Martinez-Singh, K. n., Colvard, B. n., Lee, J. T., Chandra, V. n. 2020


    Published outcomes on anterior lumbar interbody fusion (ALIF) have focused on 1-2 level fusion with and without vascular surgery assistance. We examined the influence of multi-level fusion on exposure-related outcomes when performed by vascular surgeons.We retrospectively reviewed clinical and radiographic data for patients undergoing anterior lumbar interbody fusion (ALIF) with exposure performed by vascular surgeons at a single practice.From 2017-2018, 201 consecutive patients underwent vascular-assisted ALIF. Patients were divided by number of vertebral levels exposed (90 patients with 1 level exposed, 71 with 2, 40 with 3+). Demographically, 3+ level fusion patients were older (p=.0045) and more likely to have had prior ALIF (p=.0383). Increased vertebral exposure was associated with higher rates of venous injury (p=.0251), increased procedural time (p= .0116), length of stay (p=.0001), and incidence of postoperative DVT (p=.0032). There was a 6.5% rate of intraoperative vascular injury, comprised of 3 major and 10 minor venous injuries. In patients who experienced complications, 92.3% of injuries were repaired primarily. 23% of patients with venous injuries developed postoperative deep venous thrombosis. In a multivariate logistic regression model, increased levels of exposure (RR = 6.23, p = .026) and a history of degenerative spinal disease (RR = .033, p = .033) were predictive of intraoperative venous injury.Increased vertebral exposure in anterior lumbar interbody fusion is associated with increased risk of intraoperative venous injury and postoperative deep venous thrombosis, with subsequently greater lengths of procedure time and length of stay. Rates of arterial and sympathetic injury were not affected by exposure extent.

    View details for DOI 10.1016/j.jvsv.2020.08.006

    View details for PubMedID 32795618