Antithrombotic therapy in ventricular assist device (VAD) management: From ancient beliefs to updated evidence. A narrative review

Comparing the Efficacy and Safety of Warfarin Monotherapy vs. Warfarin and Aspirin for Adult Patients With Left Ventricular Assist Devices: A Meta-Analysis

The aim of this meta-analysis was to assess the safety and efficacy of warfarin plus aspirin versus warfarin monotherapy in patients with left ventricular assist devices (LVAD). The present meta-analysis was conducted using the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Two authors systematically searched online databases, including PubMed, EMBASE, the Cochrane Library, and Web of Science from inception to December 31, 2023. Outcomes assessed in this meta-analysis included any thrombotic event, bleeding events, and all-cause mortality. A total of five articles were included in the meta-analysis, enrolling a pooled sample size of 876 patients, including 405 in the warfarin monotherapy group and 471 in the warfarin plus aspirin group. Pooled analysis showed that the risk of thrombotic events was not significantly different between the two groups (risk ratio (RR): 0.46, 95% confidence interval (CI): 0.15-1.37). The risk of bleeding events was significantly lower in patients receiving warfarin alone compared to patients receiving aspirin plus warfarin (RR: 0.67, 95% CI: 0.53-0.85). The risk of all-cause mortality was not significantly different between patients receiving warfarin alone and patients receiving aspirin plus warfarin (RR: 0.92, 95% CI: 0.65-1.30). Despite the potential benefits of discontinuing aspirin, the decision should be approached cautiously, considering the undefined risks of discontinuing anticoagulation in LVAD patients.

Retrospective Review of Secondary Prevention Strategies for Gastrointestinal Bleeding and Associated Clinical Outcomes in Left Ventricular Assist Device Patients

BACKGROUND

Gastrointestinal bleeding (GIB) is one of the most common bleeding complications associated with Left Ventricular Assist Devices (LVAD). Currently, there is no strong evidence or clear guidance for which secondary GIB prophylaxis strategy should be implemented after the discontinuation of aspirin.

METHODS

Our single-center study describes the outcomes of 26 LVAD patients who experienced a total of 49 GIB events, these individuals were either in Group-1) lower INR target range or Group-2) lower INR target plus a hemostatic agent as the secondary prophylaxis strategy. Each GIB event was considered an independent event. Outcomes assessed were bleeding reoccurrence rates, time to next GIB, acute GIB strategies, GIB-free days, thromboembolic events, survival, coagulation, and hematologic parameters.

RESULTS

GIB reoccurrence rates were not statistically different, Group-1) 9 (40.9%) vs Group-2) 15 (55.6%), p = 0.308. Danazol was utilized 81.5% of the time as the designated hemostatic agent. Additionally, no significant differences were observed with all of our secondary outcome measures for bleeding, ischemic events, or survival.

CONCLUSION

While our study was not powered to assess the clinical outcomes related to survival and thromboembolic events, no discernable increased risk of ischemic events including pump thrombosis was observed. Our data suggest that a lower INR target range plus danazol does not confer any additional benefit over a lower INR target range only approach. The results of this report are hypothesis-generating and additional studies are warranted to elucidate the optimal antithrombotic strategy and role of hemostatic agents in reducing the risk of recurrent GIB events.

Evaluation of aspirin platelet inhibition in left ventricular assist device population

INTRODUCTION

Aspirin therapy is recommended in durable left ventricular assist device (LVAD) patients to prevent thromboembolic complications. Up to 30% of patients treated with aspirin may demonstrate aspirin resistance, which has been related to thrombotic complications. However, it is unknown whether individual patients exhibit temporal alterations in aspirin sensitivity during LVAD support. We hypothesized that aspirin platelet inhibition would wane after the initial postimplant period.

METHODS

This was a retrospective, observational, single center study conducted at an academic medical center. This study evaluated changes in aspirin platelet inhibition over the first 6 months of LVAD support. Patients who underwent placement of centrifugal LVAD with aspirin platelet sensitivity assays were included for analysis. Aspirin responsiveness was assessed postimplant after 5 days, 3 months, and 6 months.

RESULTS

A total of 28 patients were included for analysis of which 7% of patients were aspirin resistant initially. At 3 months, 32% (odds ratio [OR], 6.1, p = .03) of patients were aspirin resistant and 28% (OR, 4.1, p = .1) at 6 months. Over the first 3 months postimplant, the odds of aspirin resistance increased sixfold and remained relatively constant at 6 months. Patients who were aspirin resistant and received an increase in aspirin dose at 3 months subsequently had a sensitive ARU at 6 months.

CONCLUSION

Aspirin responsiveness not only varies between patients but can significantly wane within individual LVAD patients over time. Additional study is needed to determine if monitoring aspirin resistance may prevent thrombotic complications after LVAD implantation.