Thromboelastography of Limited Benefit in LVAD Patient Management

Abstract

Purpose The role of utilizing thromboelastography (TEG) in managing antiplatelet therapy (APT) in LVAD patients is controversial. The purpose of this study was to determine if the removal of TEG from APT protocol reduced late onset bleeding without an increase in thromboembolic events. Methods We performed a single-center retrospective cohort study at the University of Florida including all recipients of a HeartMate II, HeartMate III, or Heartware LVAD between April 2005 and November 2019 (n=293). LVAD recipients before June 1st,2017 (n=221) whose APT was monitored and adjusted using TEG were compared to LVAD recipients after June 1st,2017 (n=72) where TEG was not utilized. The occurrence of late-onset bleeding events after post-operative day 7, as defined by INTERMACs major bleeding, as well as thromboembolic events were collected. Patients were followed up to one year post-implantation or to time of death, transplant, or pump exchange. APT doses, warfarin use and INR values were collected at discharge as well as 1, 3, 6 and 12 months post-implantation. Results Over a median follow-up period of 12 months, INTERMACS major bleeding events occurred in 35% of patients where TEG was utilized compared to 29% where TEG was not utilized (p-value 0.375), and procedural intervention was required in 29% compared to 18% respectively (p-value 0.058). After June 1st 2017, patients had a higher average BMI (31 compared to 29, p-value 0.020), were more likely to be on digoxin on discharge (24% compared to 12%, p-value 0.019), and were less likely to be of white race (p-value 0.043) or have ischemic cardiomyopathy (p-value 0.019). In a multivariable Cox proportional-hazards regression model including all these variables, older age was the only independent predictor of bleeding events (HR 1.03 for each additional year of age, 95% CI 1.01-1.05, p 0.008). Use of TEG was associated with use of higher doses of aspirin (>325mg 41% vs. 0%), and use of a second antiplatelet (43% vs. 1%). There was no significant difference in thromboembolic events (15% in each). Conclusion In this single center retrospective study, thromboelastography monitoring after LVAD implantation was associated with significantly higher rates of multidrug antiplatelet regimen use, at significantly higher doses, with no difference in thromboembolic events compared to LVAD patients managed without TEG. Bleeding events were more common in elderly recipients.