LACK OF CLINICALLY APPARENT HEPARIN-INDUCED THROMBO-CYTOPENIA FOLLOWING IMPLANTATION OF THE CARDIOWEST TOTAL ARTIFICIAL HEART:

Background: In patients undergoing cardiac surgery heparin-induced thrombocytopenia (HIT) is a relatively common and potentially serious complication of therapy with unfractionated heparin (UFH). Since UFH serves as the initial anticoagulant of our multi-drug regimen following implantation of the CardioWest total artificial heart (CWTAH), we wished to determine the incidence of clinically apparent HIT (CAHIT) in this patient group. Methods: Clinical data were prospectively entered into a computer database and results analyzed retrospectively. HIT was defined as a <50% decrease in PltCt relative to initial postoperative baseline value or a decrease in total PltCt to <50 x 109/L while receiving UFH postimplantation in the absence of hemorrhage. Results: 56 patients were implanted with the CWTAH and all received UFH during surgery. 26 patients (46%) had a history of previous non intra-operative UFH therapy. Patients were treated with UFH for 17 (1 to 82) ± 14 days. PltCt and Hct averaged 311 (8 to 1060) ± 133 x 109/L and 24.3 (10.8 to 24.3) ± 4.2%, respectively. CAHIT did not occur in any patient. One patient developed thrombocytopenia likely secondary to infection. Conclusions: Following implantation of the CWTAH, use of a multidrug regimen consisting of heparin, aspirin, dipyridamole and pentoxifylline resulted in no occurrences of CAHIT perhaps by stabilizing platelets resulting in a decreased release of platelet factor 4.