Abstract 13514: Serial Quantitative Assessment of Thrombogenicity in LVAD Recipients: A Case for Personalized Antithrombotic Therapy

Abstract

Introduction: Bleeding and thrombotic complication affect between 25-40% of left ventricular assist device (LVAD) recipients. Measures of thrombogenicity such as maximum platelet-fibrin clot strength (MAKH), endogenous thrombin potential (ETP) and platelet reactivity may indicate thrombotic and bleeding risk in patients on LVAD support and may vary after LVAD implantation. Methods: We prospectively assessed thrombogenicity using the novel point-of-care (TEG-6S) with PlateletMapping and the calibrated automated thrombogram (CAT) in 31 patients before and serially after LVAD implantation (HeartWare HVAD, n = 17; Heartmate II, n = 14). All LVAD patients were on aspirin 325mg/daily and warfarin (INR 2.0 to 2.5) therapy. Standard hematologic and hemolysis laboratories were compared. Results: Markers of thrombogenicity were highly variable post-LVAD. Overall, in the acute phase, MAKH, and maximum ADP-, and arachidonic acid (AA)-induced clot strength increased (p < 0.05, Table) and returned to near baseline by ≥3 months. Despite target INR values at ≥ 3 months (2.0±0.3) and antiplatelet therapy, the R-time (7.1±1.8min) remained within the normal range. Hypercoagulable patients (MAKH≥69mm) had higher endogenous thrombin potential, peak thrombin generation, WBC count, and LDH (p≤0.05). Conclusions: A state of heightened thrombogenicity indicated by high MAKH and high platelet reactivity are present in the acute phase after LVAD implantation and in selected patient during the chronic phase despite therapy with warfarin/aspirin. These findings suggest that intensification of antithrombotic therapy in a personalized fashion based on sensitive thrombogenicity testing, rather than INR should be investigated to mitigate adverse events.