Platelet reactivity is associated with pump thrombosis in patients with left ventricular assist devices

Patients with left ventricular assist devices (LVADs) are treated with a potent antithrombotic regimen to prevent pump thrombosis and thromboembolism. High on-treatment residual platelet reactivity (HRPR) is associated with ischemic outcomes in cardiovascular disease. In the current study, we investigated the prevalence and clinical impact of HRPR in stable LVAD patients. Pump thrombosis, bleeding events, and death were assessed in 62 LVAD patients (19 HeartWare HVAD [Medtronic] and 43 HeartMate 3 [Abbott]) during a 2-year follow-up. Platelet aggregation was measured by multiple electrode aggregometry, and HRPR was defined as arachidonic acid (AA)–inducible platelet aggregation of ≥21 aggregation units. Soluble P-selectin was determined by enzyme-linked immunosorbent assay. Three patients (4.8%) had pump thrombosis and 10 patients (16.1%) suffered a bleeding complication. AA-inducible platelet aggregation was significantly higher in patients with pump thrombosis (P = .01), whereas platelet aggregation in response to adenosine diphosphate (ADP) and thrombin receptor–activating peptide (TRAP) was comparable between patients without and those with pump thrombosis (both P > .05). Platelet aggregation in response to AA, ADP, and TRAP was similar in patients without and with a bleeding event (all P > .05). HRPR was detected in 29 patients (46.8%) and was associated with significantly higher platelet aggregation in response to AA, ADP, and TRAP as well as higher levels of soluble P-selectin compared with patients without HRPR (all P < .05). All pump thromboses occurred in patients with HRPR (3 vs 0; P = .06) and HVAD. Platelet reactivity is associated with pump thrombosis in LVAD patients. HRPR may represent a risk marker for pump thrombosis, particularly in HVAD patients. •Platelet reactivity is linked to ischemic and bleeding events in cardiovascular disease.•Outcomes and platelet reactivity were assessed in left ventricular assist device patients.•Platelet reactivity is associated with pump thrombosis in left ventricular assist device patients.•High on-treatment residual platelet reactivity may represent a risk marker for pump thrombosis.