Heparin antibodies and thromboembolism in heparin-coated and noncoated ventricular assist devices

Objective: Coating of ventricular assist devices (VADs) with heparin improv es the biocompatibility and may reduce the need for systemic anticoagulatio n. However, heparins are associated with the risk of formation of heparin/p latelet factor 4 antibodies (HPF4/A) and the development of heparin-associa ted thromboemboli. We analyzed the occurrence of HPF4/A and thromboembolism in patients with heparin-coated and noncoated VADs. Methods: One hundred patients were enrolled in the investigation. Fifty-sev en received a heparin-coated (group 1) and 43 a noncoated (group 2) VAD. HP F4/A testing was performed before and 2 and 12 weeks after implantation by the heparin platelet factor 4 enzyme-linked immunosorbent assay. Results: There was no significant difference in the occurrence of HPF4/A in the 2 groups (P = .102). Before the operation, 21 of the patients in group 1 had positive test responses and 25 in group 2. No patient had HPF4/A aft er termination of systemic heparinization. In group 1 there was no signific ant difference in the incidence of recurrent pump thromboses in patients wh o had positive test responses for HPF4/A (n = 11) when compared with those who had negative test responses (n = 9, P = .89). Twenty-one patients had H PF/A but no thromboembolism. However, all 22 patients who had thromboemboli sm had HPF4/A. Conclusions: Heparin coating of the VAD surface does not enhance the occurr ence of HPF4/A-associated immunologic or thrombogenic reactions. However, t he presence of these antibodies is strongly associated with an increased ri sk of thromboembolism in patients with a VAD.