Pump thrombosis (PT) is a severe complication of left ventricular assist device (LVAD) support. This study evaluated PT and bleeding after LVAD placement in patients responsive to a standard aspirin dose of 81 mg using platelet inhibition monitoring compared with initial nonresponders who were then titrated upward to achieve therapeutic response. Patients ≥ 18 years of age with initial placement of HeartMate II LVAD at our institution and at least one VerifyNow Aspirin test performed during initial hospitalization were included. The primary endpoints were bleeding and PT compared between initial aspirin responders and nonresponders. Of 85 patients, 19 (22%) were nonresponsive to initial aspirin therapy. Responders and nonresponders showed similar survival (p = 0.082), freedom from suspected/confirmed PT (p = 0.941), confirmed PT (p = 0.273), bleeding (p = 0.401), and incidence rates in PT and bleeding. Among the initial responders (<500 vs. 500–549 aspirin reaction units), there were no significant differences in survival (p = 0.177), freedom from suspected/confirmed PT (p = 0.542), confirmed PT (p = 0.159), bleeding (p = 0.879), and incidence of PT and bleeding. Platelet function testing may detect resistance to standard aspirin regimens used in LVAD patients. Dose escalation in initially nonresponsive patients to achieve responsiveness may confer a similar PT risk to patients initially responsive to standard aspirin dosing without increased bleeding risk.
From the *Department of Pharmacy Services, Medical University of South Carolina, Charleston, South Carolina; Divisions of †Division of Cardiothoracic Surgery, Medical University of South Carolina and ‡Cardiology, Medical University of South Carolina, Charleston, South Carolina; §Heart Failure and Cardiac Transplantation, The Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania; ¶Sarver Heart Center, University of Arizona, Tucson, Arizona; and ‖Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina.
Submitted for consideration August 2016; accepted for publication in revised form January 2017.
Disclosure: Dr. Jennifer Cook is a consultant for Abiomed and is a local primary investigator for St. Jude HeartMate II LVAD. The remaining authors have no conflicts of interest to report.
Correspondence: Catherine K. Floroff, Department of Pharmacy, Sentara Healthcare, 600 Gresham Drive, Norfolk, VA 23510. Email: CKFLORO1@sentara.com.