Low thromboembolism and pump thrombosis with the HeartMate II left ventricular assist device: analysis of outpatient anti-coagulation.


Journal Article

BACKGROUND: The HeartMate II (Thoratec, Pleasanton, CA) is an effective bridge to transplantation (BTT) but requires anti-coagulation with warfarin and aspirin. We evaluated the risk of thromboembolism and hemorrhage related to the degree of anti-coagulation as reflected by the international normalized ratio (INR). METHODS: INRs were measured monthly for 6 months in all discharged HeartMate II BTT patients and at an event. Each INR was assigned to ranges of INRs. Adverse events analyzed were ischemic and hemorrhagic stroke, pump thrombosis, and bleeding requiring surgery or transfusion. Events were correlated to the INR during the event and at the start of the month. RESULTS: In 331 patients discharged on support, 10 had thrombotic events (9 ischemic strokes, 3 pump thromboses), and 58 had hemorrhagic events (7 strokes, 4 hemorrhages requiring surgery, and 102 requiring transfusions). The median INR was 2.1 at discharge and 1.90 at 6 months. Although the incidence of stroke was low, 40% of ischemic strokes occurred in patients with INRs < 1.5 and 33% of hemorrhagic strokes were in patients with INRs > 3.0. The highest incidence of bleeding was at INRs > 2.5. CONCLUSIONS: The rate of thromboembolism during long-term outpatient support with the HeartMate II is low. The low number of thrombotic events appears to be offset by a greater number of hemorrhagic events. An appropriate target INR is 1.5 to 2.5 in addition to aspirin therapy. In patients having recurrent episodes of bleeding, the risk of lowering the target INR appears to be small.

Full Text

Duke Authors

Cited Authors

  • Boyle, AJ; Russell, SD; Teuteberg, JJ; Slaughter, MS; Moazami, N; Pagani, FD; Frazier, OH; Heatley, G; Farrar, DJ; John, R

Published Date

  • September 2009

Published In

Volume / Issue

  • 28 / 9

Start / End Page

  • 881 - 887

PubMed ID

  • 19716039

Pubmed Central ID

  • 19716039

Electronic International Standard Serial Number (EISSN)

  • 1557-3117

Digital Object Identifier (DOI)

  • 10.1016/j.healun.2009.05.018


  • eng

Conference Location

  • United States