CARC13: Evaluation of Response to Aspirin Platelet Therapy and Hemocompatibility-Related Adverse Events with the HeartMate 3 Left Ventricular Assist Device

Background: Left ventricular assist device (LVAD) patients usually are prescribed a combination of anticoagulation and aspirin (ASA) therapy. HeartMate 3 (HM3) demonstrates reduced hemocompatibility-related adverse events (HRAEs) including stroke, thrombosis and bleeding. However, it's not known whether ASA responders vs. non-responders are non-inferior in the incidence of HRAEs, and whether there are temporal changes in ASA sensitivity during HM3 support. Methods: This prospective, observational, single-center cohort study included 21 HM3 LVAD patients (Age: 59.0±11.1 years, female: 4.8%, BMI: 29.6±6.1kg/m2) implanted between 2019 and 2021, with serial ASA platelet sensitivity assays (VerifyNow Assay). ASA platelet therapy resistance was defined by ASA reactivity units (ARU) > 550. Primary endpoint was the incidence of HRAEs (ASA responders vs. non-responders) 6 months before initial assessment and until the next outpatient follow-up visit (3 months ± 30 days). Secondary endpoint was the temporal change in ASA resistance. Results: Eight (38.1%) patients were ASA resistant at the first ARU assessment (426 days after HM3 implantation) and 21.1% (p=0.38) during follow-up, without ARU changes over time (512±64 vs. 491±53, p=0.22). ASA responders and non-responders received a comparable ASA daily dose per-protocol (108±28mg vs. 100±28mg, p=0.43), without significant differences in baseline demographics (age: 62±9 vs. 55±14 years, p=0.17; female: 0% vs. 12.5%, p=0.38; BMI: 29±7 vs. 32±3, p=0.55; ischemic heart failure: 46.2% vs. 25.0%, p=0.45) or risk factors (Atrial fibrillation: 30.8% vs. 25.0%, diabetes: 30.8% vs. 37.5% and stroke history: 15.4% vs. 12.5%, p>0.99). The incidence of HRAEs was comparable between ASA responders and non-responders 6 months before the first measurement (15.4% vs. 0.0%, p=0.26) and between the two ARU measurements (0.0% vs. 12.5%, p=0.22). Conclusion: Although the ASA resistance varies considerably between LVAD outpatients, without significant changes over time, the HM3 demonstrated excellent hemocompatibility. Further large-scale multicenter studies are needed to confirm the findings of this study that ASA plays only a minor role in antithrombotic treatment with HM3 and can be safely removed.