Anticoagulation control has been associated with risk of thromboembolism and hemorrhage. Herein, we explore the relationship between anticoagulation control achieved in left ventricular assist device (LVAD) patients and evaluate the association with risk of thromboembolism and hemorrhage. Patients (19 years old or older) with a continuous flow LVAD placed from 2006 to 2012. Percent time spent in target range (PTTR) for international normalized ratio (INR) was estimated with target range of 2.0–3.0. Proportion of time spent in target range was categorized into PTTR > 60%, PTTR ≥ 50 < 60%, and PTTR < 50%. The relationship between PTTR and thromboembolism and hemorrhage was assessed. One hundred fifteen participants contributed 624.5 months of follow-up time. Only 20% of patients achieved anticoagulation control (PTTR > 60% for INR range of 2–3). After adjusting for chronic kidney disease, history of diabetes, history of atrial fibrillation, and age at implant, compared with patients with PTTR < 50%, the relative risk of thromboembolism in patients with PTTR ≥ 60% (hazard ratio [HR]: 0.37; 95% confidence interval [CI]: 0.14–0.96; p = 0.042) was significantly lower, but not for patients with a PTTR of ≥ 50 < 60% (HR: 0.21; 95% CI: 0.02–1.82; p = 0.16). The relative risk for hemorrhage was also significantly lower among patients with a PTTR ≥ 60% (HR: 0.45; 95% CI: 0.21–0.98; p = 0.045), but not among those with PTTR of ≥ 50 < 60% (HR: 0.47; 95% CI: 0.14–1.56; p = 0.22). This current study demonstrates that LVAD patients remain in the INR target range an average of 42.9% of the time. To our knowledge, this is the first report with regard to anticoagulation control as assessed by PTTR and its association with thromboembolism, hemorrhage, or death among patients with ventricular assist devices (VADs).
From the *Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama; †Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama; ‡Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; §Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; ¶Division of Cardiothoracic Surgery, Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama; ‖Department of Biostatistics, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama; and #Heart South Cardiovascular Group, Columbiana, Alabama.
Submitted for consideration October 2016; accepted for publication in revised form April 2017.
This work was supported, in part, by grants from the National Heart Lung and Blood Institute (RO1HL092173; 1K24HL133373), the National Institutes of Health (NIH) Clinical and Translational Science Award (CTSA) program (UL1 TR000165), and the American Heart Association (13PRE13830003).
Disclosure: The authors have no conflicts of interest to report.
Correspondence: Nita A. Limdi, Department of Neurology, University of Alabama at Birmingham, 1235 Jefferson Tower, 625 19th Street South, Birmingham AL 35294-0021. Email: firstname.lastname@example.org.