Impact of Using a Low Anti-Xa Target Heparin Protocol on Hemocompatibility-Related Outcomes after Implantation of a HeartMate 3 Device

Purpose To evaluate early hemocompatibility-related outcomes after implementation of a low anti-Xa target heparin protocol following implantation of the HeartMate 3 Left Ventricular Assist Device (LVAD). Methods We reviewed hemocompatibility-related outcomes including mediastinal bleeding, gastrointestinal bleeding (GIB), stroke, and pump thrombosis (PT) events in recipients of HeartMate 3 LVADs before and after implementation of a low anti-Xa target heparin protocol. The higher anti-Xa protocol targeted levels of 0.3-0.5 IU/ml using a starting dose of 18 units/kg/hr with a maximum starting dose of 1530 units/hr, and the lower anti-Xa protocol targeted levels of 0.1-0.3 IU/ml using a starting dose of 7 units/kg/hr with a maximum starting dose of 595 units/hr. Results Between 9/2018 and 8/2020, 152 patients were implanted with a HeartMate 3. Mean patient age was 57 ± 12 years, 74% were males, and 76% of patients were African American. Per our center's protocol, IV heparin was started on postoperative day 5. 106 patients were treated with the higher anti-Xa protocol and 21 patients were treated with the lower anti-Xa protocol. The patients treated with the higher anti-Xa target protocol experienced 10 (9.4%) post-operative mediastinal bleeding events requiring return to the operating room (OR) while patients on the lower anti-Xa protocol experienced none. Patients treated with the higher anti-Xa target protocol experienced 8 (7.5%) GIB events within 60 days of implant while patients on the lower anti-Xa protocol experienced no GIB. Patients treated with the higher anti-Xa protocol experienced one hemorrhagic stroke and no ischemic strokes, while patients on the lower anti-Xa protocol experienced one ischemic stroke and no hemorrhagic strokes. No PT events requiring pump exchange occurred in either group. Conclusion Implementation of a low anti-Xa target heparin protocol after HeartMate 3 LVAD implantation surgery was associated with a lower incidence of mediastinal and GI bleeding. No PT events requiring pump exchange were observed in either group. Stroke rate was low in both groups. Further research is needed to determine the safest and most effective anticoagulation protocol after HeartMate 3 implantation that lowers the incidence of early hemocompatibility-related events.