Thrombosis After LVAD Implantation Is on the Rise

Summary and Comment |
January 2, 2014

Thrombosis After LVAD Implantation Is on the Rise

  1. Frederick A. Masoudi, MD, MSPH, FACC, FAHA

At three high-volume institutions, the rate of thrombosis in the first 3 months after implantation of the HeartMate II device nearly quadrupled within a span of 2 years.

  1. Frederick A. Masoudi, MD, MSPH, FACC, FAHA

The HeartMate II left ventricular assist device (LVAD), as a bridge to transplantation or as “destination” therapy, has dramatically changed how advanced heart failure is managed. In clinical trials and postmarketing studies, the rate of thrombosis — a feared LVAD complication — has ranged from 2% to 4%. A higher thrombosis rate documented during quality review at a single center prompted investigators from three high-volume institutions to assess pump thromboses in a cohort of 837 patients (mean age, 55; 79% men) who had 895 HeartMate II devices implanted from 2004 to mid 2013.

Seventy-two LVAD thromboses were confirmed in 66 patients, and an additional 36 were suspected. The overall monthly risk for confirmed thrombosis peaked at 1.4% within the first month after implantation, then declined and leveled off at 0.4% per month. The occurrence of confirmed thrombosis within the first 3 months after implantation increased substantially (from 2.2% before March 2011 to 8.4% by early 2013) and consistently across the three institutions. Furthermore, the median time to occurrence of confirmed thrombosis declined from 18.6 months, before March 2011, to 2.7 months thereafter. Lactate dehydrogenase (LDH) elevations (>1000 IU/liter) closely paralleled pump thromboses and, on average, increased substantially during the weeks preceding the events.

Of the 72 confirmed thromboses, 11 were treated with heart transplantation, 21 with pump replacement, 2 with pump removal, and 38 with medical therapy (anticoagulation and thrombolysis). Throughout follow-up, mortality was substantially higher among patients with thrombosis than among those without it (36% vs. 17% at 180 days).


At three high-volume centers that use the HeartMate II, the risk for pump thrombosis is substantially higher than that documented by the studies that supported FDA approval, has increased precipitously, and is associated with a dire prognosis. Potential explanations require prompt investigation. Meanwhile, clinicians and patients considering LVAD therapy should incorporate this important information into decision making. Also, LDH elevation may be an important precursor to HeartMate II thrombosis.

Editor Disclosures at Time of Publication

  • Disclosures for Frederick A. Masoudi, MD, MSPH, FACC, FAHA at time of publication Royalties Darling, Milligan, Smith & Lesch Grant / research support Agency for Healthcare Research and Quality; American College of Cardiology; Patient-Centered Outcomes Research Institute Editorial boards Circulation: Cardiovascular Quality and Outcomes Leadership positions in professional societies American College of Cardiology (Senior Medical Officer, National Cardiovascular Data Registries); American Heart Association (Vice Chair, Council on Quality of Care and Outcomes Research)


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