Enhanced Hemocompatibility via Bivalirudin and Bicarbonate as Alternative to Heparin in a Catheter-Based Axial-Flow System

Background: Cardiovascular therapeutic devices typically require systemic heparin due to underlying thrombotic risk. The Impella axial flow system further relies on internal perfusion with either a heparin-containing or sodium bicarbonate purge solution during operation. The combination of systemic and device-mediated heparin often contributes to varying levels of overall anticoagulation, raising the possibility of increased bleeding risk and complications due to heparin sensitivity. To reduce adverse events, efforts have been ongoing to eliminate heparin, both systemically and via the device. Here, we investigate bivalirudin as an alternative to systemic heparin and sodium bicarbonate as an alternative to local device heparin in the purge solution. Methods: We examined hemocompatibility in a mock loop environment with circulating whole porcine blood to determine feasibility of heparin-free Impella system. Anticoagulated (heparin or bivalirudin) blood was loaded into a circulatory loop with a contained Impella 5.5 and run for 4 h with either heparin or sodium bicarbonate-containing purge solution. Blood samples were collected serially and analyzed for metrics of hemocompatibility: hemolysis, platelet activation, and vWF degradation. Results: Bivalirudin and sodium bicarbonate adjunctive environment led to similar or improved hemocompatibility as compared to heparin-containing environment—notably, decreased hemolysis (40 ± 20.8 mg/dL average decrease) and preserved platelet activity measured by P-selectin exposure (8.0 ± 5.6% average increase). Conclusions: Our data supports the potential to create an overall heparin-free approach simplifying anticoagulation management, offering potential for overall reduced bleeding risk and heparin-related complications.