Close antiplatelet therapy monitoring and adjustment based upon thrombelastography may reduce late-onset bleeding in HeartMate II recipients

Abstract

Objectives: Bleeding is the most common complication of HeartMate II and is partially attributable to platelet dysfunction; however, antiplatelet therapy is arbitrary in most centres. We investigated how antiplatelet therapy adjustment with thrombelastography affects late-onset bleeding.

Methods: Thrombelastography was used to adjust antiplatelet therapy in 57 HeartMate II recipients. Kaplan-Meier survival curves and Cox proportional hazard ratio model were used to identify predictors of late-onset bleeding in univariate and multivariate analysis. Finally, late-onset bleeding rate in our study was compared with the reported rates in other studies in the literature, all of which did not use any test to monitor or adjust antiplatelet therapy.

Results: Mean follow-up was 347 days. Eighteen late-onset bleeding events occurred in 12 patients, a late-onset bleeding rate of 12/57 (21%) or 0.21 events/patient-year. The Kaplan-Meier survival curves demonstrated that late-onset bleeding was more common in the destination therapy cohort (P = 0.02), in patients older than 60 years (P = 0.04) and in females (P = 0.01), none of which was significant in multivariate analysis at a significance level of 0.05. To further investigate the higher bleeding rate in elderly patients, thrombelastography parameters were compared between younger and older patients at the age cut-off of 60 years which demonstrated a prothrombotic change the day after device implantation in younger patients that was absent in the elderly. There was also a trend towards higher requirement for antiplatelet therapy in younger patients while on device support, but the difference did not reach statistical significance. The average late-onset or gastrointestinal bleeding rate among seven comparable studies in the literature that did not use any monitoring test to adjust antiplatelet therapy was 0.49 events/patient-year.

Conclusions: Our study implicates that antiplatelet therapy adjustment with thrombelastography may reduce late-onset bleeding rate in HeartMate II recipients. Bleeding was more common in the elderly recipients and analysis of thrombelastography data suggests that a less aggressive antiplatelet therapy regimen could potentially lower bleeding rate in this vulnerable population.

Keywords: Bleeding; HeartMate II; Stroke; Thrombelastography; Thromboembolism.

Figure 1:

Kaplan–Meier bleeding-free survival curve: (A) bridge to transplantation vs destination therapy; (B) age = <60 vs age >60 and (C) male vs female. The numbers at the bottom of the figures show numbers of patients at risk at the beginning of each interval.

Figure 2:

Comparison between TEG-MA (A) and INR (B) values at routine follow-up vs at the time of bleeding or TE complication.

Figure 3:

Maximum outpatient APT during follow-up. ASA, aspirin; doses are mg/day; n represents number of patients.

Figure 4:

TEG profile of younger and older patients at various follow-up intervals. Error bars represent one standard error around mean.