Thrombosis in Ventricular Assist Devices

Bethesda, MD


In collaboration with FDA’s Center for Devices and Radiologic Health, the NHLBI convened a workshop on the Current State of Thrombosis in Ventricular Assist Devices (VADs) on May 14, 2015, in Baltimore, Maryland. The workshop included cardiac surgeons, cardiologists, biostatisticians, bioengineers, and representatives from FDA, CMS, and the NHLBI to review available data on pump thrombosis, a major and potentially fatal complication of durable continuous-flow VADs, which are mechanical pumps that are used to support heart function and blood flow in people who have weakened hearts. Workshop members discussed possible approaches to mitigate pump thrombosis and other device-related serious adverse outcomes.

The workshop had the following specific goals:

  • Review the available data on instances of pump thrombosis in currently marketed VADs by examining available evidence from clinical trials and relevant data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS), which includes a repository of clinical, demographic, and device-related information on patients who have VADs.
  • Discuss device-associated risks and how best to mitigate them in clinical practice and research settings.
  • Identify research needs and trial opportunities.
  • Provide guidance on the conduct of interventional trials in advanced heart failure patients receiving VADs.



Since their initial development, VADs have extended and improved survival for thousands of advanced heart failure patients. However, recent findings have highlighted the risks involved in using these devices. For example, in November 2013, writing in the NEJM, investigators at the Cleveland Clinic reported an increase in the apparent rate of pump thrombosis. The INTERMACS investigators also published similar findings based on registry data in the Journal of Heart and Lung Transplantation (JHLT).

Since these reports were released, clinicians, researchers, regulatory agencies, and industry have closely monitored the incidence of pump thrombosis and had extensive discussions as to the cause and appropriate response to the apparent increase in pump thrombosis. In the spring of 2015, the NHLBI and FDA asked INTERMACS investigators to conduct an updated analysis of the pump thrombosis data. In response to this request, the University of Alabama at Birmingham, Cleveland Clinic, and the NHLBI, three organizations involved in INTERMACS, collaborated to conduct three independent analyses of INTERMACS data.

At the workshop, these three organizations presented the results of their analyses. In addition, others presented information on the following topics:

  • clinical insights concerning pump thrombosis and stroke in German clinical practice;
  • the FDA perspective on adverse event profiles of VADs; and
  • findings from three clinical trials involving VADs—Endurance, Roadmap, and REVIVE-IT.

After these presentations, workshop participants discussed the following potential areas to mitigate pump thrombosis and associated events:

  • pump speed (rate of flow) and pulsatility (the manner with which the device pumps the blood);
  • anticoagulation therapies and general patient management;
  • criteria for patient selection for VADs and pump selection; and
  • surgical techniques and pump placement.

Workshop Outcome:

Based on the presentation and discussion, workshop participants identified a set of research and policy priorities that may improve the safe use and study of current and future devices. These priorities include the following:

  1. Evaluation of potential differences between clinical sites, both those in the U.S. and Europe, in the incidence of pump thrombosis and related events.
  2. Further investigation, possibly through a nested cohort study, of practice-specific and care management approaches to mitigate adverse outcomes, including the following approaches:  anticoagulation, INR monitoring (which enables a determination of the effectiveness of anticoagulation therapy), assessment of platelet factors, and control of blood pressure, among other approaches. Such a study might also consider trans-continental differences.
  3. Development of a white paper facilitated by the NHLBI, FDA, CMS, and the medical societies to define the critical data elements that researchers should collect in future trials and registries pertaining to VADs.

In addition, workshop participants made suggestions concerning planned trials:

  • Potential benefit of VADs in patients who are less sick than the patients for whom the device is approved — the workshop participants suggested that such a trial should not be launched until new VADs with improved safety profiles become available, which could occur in the next 5–10 years.
  • Interventional trials involving heart failure patients receiving VADs — the workshop participants suggested that such trials utilize risk mitigation approaches and that the investigators rigorously monitor patients.

Publication Plans:

The INTERMACS analyses are slated for publication in the JHLT. A proceedings from this workshop is in development for publication in a peer-reviewed journal.


  • Jim Young, M.D., Cleveland Clinic

Presenters and Moderators:

  • James Kirklin, M.D., University of Alabama at Birmingham
  • Eugene Blackstone, M.D., Cleveland Clinic
  • Neal Jeffries, Ph.D., NHLBI
  • Martin Strueber, M.D., Spectrum Health
  • John Saperstein, M.D., FDA
  • Francis Pagani, M.D., Ph.D., University of Michigan
  • Randall Starling, M.D., M.P.H., Cleveland Clinic
  • Keigh Aaronson, M.D., M.S., University of Michigan
  • Patrick O’Gara, M.D., Brigham and Women’s Hospital
  • Todd Massey, M.D., University of Rochester
  • Jerry Estep, M.D., Methodist Hospital
  • Terry Yau, M.D., Toronto General Hospital
  • Robert Kormos, University of Pittsburgh Medical Center
  • Joseph Rogers, M.D., Duke University
  • Edwardo Rame, M.D., University of Pennsylvania
  • Michael Acker, M.D., University of Pennsylvania

NHLBI Staff:

  • Marissa Miller, D.V.M., M.P.H
  • J. Timothy Baldwin, Ph.D.
  • Wendy Taddei-Peters, Ph.D.
  • Neal Jeffries, Ph.D.
  • Catherine Burke, M.A.


  • Fernando Aguel, M.S.E., FDA
  • Deborah Ascheim, M.D., Mt. Sinai Medical Center
  • Lori Ashby, M.A., CMS
  • Daniel Caños, Ph.D., M.P.H., FDA
  • Ryan Cantor, M.S., M.P.H., University of Alabama, Birmingham
  • Mary Lynne Clark, B.S., University of Alabama, Birmingham
  • Craig Collum, M.P.H., University of Alabama, Birmingham
  • Arielle Drummond, Ph.D., FDA
  • Annetine Gelijns, Ph.D., Mt. Sinai Medical Center
  • Lydia Glaw, Ph.D., FDA
  • Claire Hambright, B.S., FDA
  • Matthew Hillebrenner, M.S.E., FDA
  • Douglas Horstmanshof, M.D., INTEGRIS Health
  • James Long, M.D., Ph.D., INTEGRIS Health
  • Julie Marders, R.N., M.S., FDA
  • Janella Miller, R.N., B.S.N., University of Alabama, Birmingham
  • Nicole Milligan, FDA
  • Susan Myers, B.B.A., Q.M.I.S., University of Alabama, Birmingham
  • David Naftel,  Ph.D., University of Alabama, Birmingham
  • Ileana Piña, M.D., M.P.H., FDA
  • Jean Rinaldi, Ph.D., FDA
  • Stuart Russell, M.D., Johns Hopkins University
  • Jyme Schafer, M.D., M.P.H., CMS
  • Craig Selzman, M.D., University of Utah
  • Mark Slaughter, M.D., University of Louisville
  • Nick Smedira, M.D., Cleveland Clinic Foundation
  • Josef Stehlik, M.D., M.P.H., University of Utah
  • Garrick Stewart, M.D., Harvard/Brigham & Women's Hospital
  • Joseph Su, Ph.D., M.P.H., FDA
  • Leon Sun, Ph.D., FDA

Staff Contact:

Marissa Miller, D.V.M., M.P.H.  Tel: 301 594 1542