Multicenter Registry Analysis of Bivalirudin for Primary Anticoagulation in Pediatric HeartMate 3 Recipients: ACTION Analysis

Bivalirudin, a direct thrombin inhibitor, is increasingly used as an alternative to heparin in pediatric mechanical circulatory support (MCS) and has resulted in improved stroke-free survival in children supported by paracorporeal pulsatile devices. However, for those supported by implanted continuous-flow devices, such as HeartMate 3, significant practice variation exists in agents used as early intravenous anticoagulation. Leveraging ACTION VAD registry data, we sought to compare early hemocompatibility-related adverse events (<14 days) in pediatric HeartMate 3 patients on bivalirudin versus heparin (unfractionated heparin [UFH]). A total of 234 patients, aged under 25 years, with a median age of 15 years and a median weight of 60 kg, at the time of HeartMate 3 implant, were included in the study cohort. Of these, 100 (42.7%) received bivalirudin as initial intravenous anticoagulation agent and 134 (57.2%) received UFH. With data censored at change of agent, there was no significant difference between the groups for freedom from stroke (96.9% vs. 96.3%, p = 0.77) or bleeding (94.8% vs. 89.9% %, p = 0.21), but time to transition to oral anticoagulation was longer for the bivalirudin group. Survival at 1 year after implant was also not different between groups. These data suggest that bivalirudin is a reasonable alternative to UFH for early thromboprophylaxis after HeartMate 3 implantation.