Management of cardiac surgery patients with Heparin-Induced Thrombocytopenia (HIT-II): experience with preoperative plasmaphereses plus intraoperative heparin

Abstract

Rationale: Heparin-induced thrombocytopenia (HIT) is a drug-induced, immune-mediated type of thrombocytopenia. Its incidence is continuously increasing. HIT poses a tremendous surgical challenge, specifically in cardiothoracic surgery where heparin is the only anticoagulant drug that can be used during cardiopulmonary bypass (CPB) with the possibility of antagonization at the end of surgery. Anticoagulants that are approved for treatment of HIT (lepirudin, argatroban, danaparoid, bivalirudin) are not approved for CPB, and may pose great bleeding risks due to their lack of antagonization. Based on the antibody-mediated nature of the disease, we reasoned that it may be possible to eliminate HIT antibodies by plasmaphereses preoperatively, allowing heparin and protamin to be used during the main surgical procedure. Objective: We here report our first experience with plasmaphereses in 8 HIT II-positive patients undergoing major cardiothoracic surgery using heparin/protamin. Methods: The Patients received the following operative procedures: heart-transplantation (n=4), lung-transplantation (n=1), heart-lung-transplantation (n=1) and elective aortic valve replacement (n=2). HIT II was confirmed in all 8 patients and anticoagulant treatment was performed with argatroban until the time of surgery (or until the beginning of plasmaphereses). The transplant patients received a single run of plasmaphereses immediately after the donor organ was accepted and before transplantation. The patients requiring aortic valve replacement received two or three episodes of plasmaphereses and postprocedural verification that HIT antibodies had been fully eliminated. The surgical procedures were then performed using standard heparin/protamin. Postopoerative anticoagulation was again conducted with argatroban. Results: All patients survived the operation and are still alive. There were no complications or side effects during the plasma exchange. The use of heparin during the transplantation or valve replacement was free of complications. No thromboembolic or bleeding complications were observed. Conclusions: The results suggest that preoperative plasma exchange to eliminate circulating anti-heparin antibodies in HIT-II positive patients and using heparin during a major cardiothoracic procedure is safe. The technique may allow a safer and technically easier treatment of a continuously growing group of patients, specifically transplant patients. However, more experience is needed to verify this suggestion.