P64: Rotational Thromboelastometry Predictors of Thrombosis in Patients with a Left Ventricular Assist Device

Abstract

Background: Left ventricular assist devices (LVADs) prolong survival and improve quality of life for patients with advanced heart failure. They are also associated with a variety of complications including thrombotic events. Viscoelastic testing with rotational thromboelastometry (ROTEM) can be used to screen for coagulopathy in a variety of conditions, however, its utility in patients with an LVAD remains unclear. The purpose of this study was to identify ROTEM characteristics associated with thrombosis in hospitalized patients with an LVAD. Methods: This was a single-center, retrospective cohort study of patients with an LVAD who were hospitalized from January 1, 2013, to December 1, 2022. ROTEMs collected during the first 24 hours of hospitalization from patients with confirmed thrombosis were compared to those of patients without thrombosis. Thrombosis was defined as either ischemic stroke, pump thrombosis, or arterial or venous thrombi. Up to five ROTEMs each, consisting of INTEM, EXTEM, and FIBTEM, were collected per patient. Exclusion criteria included ROTEMs collected during the patient’s implant hospitalization or bleeding admission, or patient received a parenteral antithrombotic agent, parenteral antiplatelet agent, reversal agent, or blood product within 48 hours of ROTEM collection. A univariable binary logistic regression model was used to estimate the unadjusted effects of each ROTEM characteristic. Type III Wald Chi-square p-values were reported for each variable. Results: A total of 238 ROTEMs were included in the study with 39 in the thrombosis group and 199 in the non-thrombosis group. At baseline, history of a clotting event (56.4% vs. 37.2%, p=0.03) and age (61.9 + 13.8 vs. 56.6 + 15, p=0.04) were higher in the thrombosis group, while the remaining characteristics were similar between both groups. For the primary outcome, there was no statistically significant difference in EXTEM maximum clot firmness between patients with thrombosis compared to patients without thrombosis (71.6 + 10 vs. 69.7 + 7.9, p=0.20). For secondary outcomes, FIBTEM maximum clot firmness (31.1 + 13.0 vs. 26.8 + 10.6, p=0.03) and FIBTEM amplitude at 20 minutes (30.5 + 12.8 vs. 26.5 + 10.4, p=0.04) were both higher in the thrombosis group compared to the non-thrombosis group. Conclusion: The utility of viscoelastic testing in patients with an LVAD has remained unclear with the limited amount of literature currently available. This study was the first of its class to assess ROTEM characteristics upon hospital admission to screen for coagulopathy in patients with an LVAD. ROTEM characteristics including FIBTEM maximum clot firmness and FIBTEM amplitude at 20 minutes may be utilized as screening tools to identify patients at an increased risk for thrombosis.