Primary Anticoagulation With Bivalirudin Versus Heparin for Microaxial Flow Pump Supported Patients.

Hemocompatibility adverse events are frequent in critically ill patients on microaxial flow pump (mAFP) support. Promising experience has accumulated on the use of primary direct thrombin inhibitor (DTI) for anticoagulation in temporary mechanical circulatory support (tMCS). The aim of the study was to compare DTI-based with heparin-based anticoagulation in cardiogenic shock (CS) patients on mAFP. We collected data from 180 adult CS patients supported with mAFP at two referral centers from 2018 to 2023. Patients received primary intravenous anticoagulation with heparin (n = 85, 47%) or bivalirudin (n = 95, 53%) according to institutional protocols. The inverse probability weighting (IPWT) was used to balance treatment groups. Society of Cardiovascular and Angiography Interventions (SCAI) class at mAFP implantation was C in 73 (41%) patients, D in 80 (44%), E in 20 (11%). Impella CP was the most implanted mAFP (85 patients, 47%), followed by Impella 5.5 (65, 36%), Impella 5.0 (28, 16%), and Impella 2.5 (2, 1%). The bleeding rate was 27%, and the thrombosis rate was less than 10%. At IPWT, clinical (overall, major and minor bleeding, major and minor hemolysis) and survival outcomes were comparable. Patients in the DTI group had fewer aPTT variations of greater than 20% and aPTT values exceeding 80 seconds ( p < 0.001). In the largest available study performed in mAFP patients, DTI for anticoagulation was comparable to heparin with a possibly more stable effect on aPTT.