Thrombosis and Cable Damage in the HeartWare Pump

Abstract

Exchange of the HeartWare HVAD made necessary by thrombosis or cable damage is rare, but it is a complex procedure associated with morbidity. Less invasive exchange procedures may contribute to faster postoperative recovery and early mobilization. Between September 2009 and April 2012, 225 patients (median age 55.4 years, range 7-82 years, 40 of them women) were supported with the HeartWare HVAD at our institution. Cumulative follow-up in all 225 patients was 151.9 patient/years. In six patients, early pump thrombosis (<30 days) requiring pump exchange occurred after a median time of 7 (2-9) days. In six patients, late pump thrombosis requiring pump exchange occurred after a median of 380 (84-705) days. The overall incidence was 5.3% with 0.079 thromboses per year. In two instances of accidental cable damage as a result of massive external mechanical impact, pump exchange was necessary. We describe a safe and less invasive technique for the explantation and exchange of the HeartWare HVAD through a left thoracotomy. Pump thrombosis of the HeartWare HVAD is a very rare condition caused mostly by new onset of heparin-induced thrombocytopenia type II, mismanagement of anticoagulation, or hypercoagulability in the case of severe sepsis. Since the introduction of the sintered inflow cannula no early thrombosis has occurred. Pump exchange in the case of hemolysis should not be delayed. The cable of the HeartWare HVAD is very reliable and breaks only after excessive external impact. A minimally invasive approach for pump exchange on cardiopulmonary bypass for pump thrombosis and off-pump for cable damage or pump explantation is recommended.