Meta-Analysis of Time in Therapeutic Range in Continuous-Flow Left Ventricular Assist Device Patients Receiving Warfarin

Abstract

Continuous-flow left ventricular assist devices (CF-LVADs) prolong survival in advanced heart failure patients. Anticoagulation control is critical in CF-LVAD patients due to increased thromboembolic and bleeding risk. We assessed the quality of INR control in CF-LVAD patients measured by time in therapeutic range (TTR). We performed a systematic literature search of MEDLINE and SCOPUS through July 2017 to identify studies evaluating TTR in anticoagulated adult CF-LVAD patients. Data on key characteristics and the TTR end point were then extracted from each study by two investigators using a standardized tool. Using a Hartung-Knapp random effects model, a weighted mean TTR estimate with accompanying 95% confidence interval (CI) was calculated. Statistical heterogeneity was estimated using the I² statistic. Five published studies were included. All studies were single-center, retrospective investigations that calculated TTR using the Rosendaal method. Sample sizes ranged from 11 to 115 patients (total of 270 patients) with durations of follow-up ranging from 9 to 76 person-years. On meta-analysis, CF-LVAD patients had a weighted mean TTR of 46.6% (95% CI: 36.0-57.3%, I² = 94%). This suggests that warfarin is difficult to manage in CF-LVAD patients, which may contribute to high rates of bleeding and thromboembolic complications.

Keywords: -Anticoagulants; -Mechanical circulatory support; -Meta-analysis; Left ventricular assist device.