Abstract 16863: Does Maintenance Anticoagulation Variability Influence Adverse Outcomes in Patients with Continuous Flow Left Ventricular Assist Devices?

Abstract

Introduction: Anticoagulation (AC) with vitamin K antagonists (VKA) are used to reduce the risk of thrombus in patients with continuous flow left ventricular assist devices (CF-LVAD). Hypothesis: We sought to determine if AC variability was associated with adverse bleeding or thrombus outcomes in CF-LVAD patients. Methods: We analyzed VKA AC variability during the maintenance AC phase from 30 to 90 days in 91 CF-LVAD (HeartMate-II 49, HeartWare 42) patients between 2011 and 2014. Patients were divided into AE and NO AE groups based on bleeding and thrombus outcomes. VKA AC data (measured and interpolated INR values, INR frequency, VKA dose), medications that affect VKA metabolism, markers of hepatic function and anti-platelet agents were compared between groups. Results: Baseline (mean age 52±12, male 79%, INTERMACS 3/4 80%) and perioperative (bypass time 82±48, length of stay 15.4±7.3) characteristics were comparable between AE and NO AE groups (all p>0.05). Adverse outcomes occurred in 12 (13%) patients (bleeding= 4, pump thrombus=6, stroke=2). In the overall cohort, patients spent a median time of 63% (47, 78) in therapeutic INR (2-3) range during maintenance phase VKA AC. Interestingly, variation in maintenance phase AC was comparable between AE and NO AE groups (all p>0.05; Table). Medications that affect VKA metabolism, hepatic function and anti-platelet medications were similar between groups (all p>0.05) (Table). Time in therapeutic range was comparable between devices (HM-II 56% vs HW 65%; p=0.09). Conclusions: During maintenance VKA anticoagulation, CF-LVAD patients spent 37% of time outside the therapeutic INR range. VKA anticoagulation variability, antiplatelet therapy and medications that affect VKA metabolism were not associated with bleeding or thrombus outcomes. Investigation into other variables that may account for recently reported increased adverse events are urgently needed.