The Use of Cangrelor and Heparin for Anticoagulation in a Patient Requiring Pulmonary Thromboendarterectomy Surgery with Suspected Heparin-Induced Thrombocytopenia

Abstract

The management of heparin-induced thrombocytopenia (HIT) in the perioperative period for patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) can be a challenging clinical scenario. Once a diagnosis of HIT has been established, heparin products typically are avoided and alternative therapies for anticoagulation are started. Alternative anticoagulation strategies for CPB are limited and often have various pharmacokinetic profiles that may lead to increased perioperative bleeding. Historically the use of a GPIIb/IIIa inhibitor, such as tirofiban, followed by unfractionated heparin (UFH) is the typical alternative for surgeries requiring DHCA in patients with HIT at the authors' institution. This article presents a case in which cangrelor followed by UFH was used in a 20-year-old patient with suspected HIT and chronic thromboembolic pulmonary hypertension undergoing pulmonary thromboendarterectomy surgery requiring CPB and DHCA. Due to the frequency of significant postoperative bleeding encountered when using tirofiban and UFH, it was decided to attempt to block platelet aggregation with significantly shorter-acting cangrelor. The authors hypothesized that cangrelor would reduce the risk of significant bleeding compared with tirofiban because of its favorable pharmacokinetics. Specifically, cangrelor has a short elimination half-life of 3 to 6 minutes, and its elimination is not altered by renal and hepatic impairment. This case report discusses the pathophysiology of HIT, the alternative anticoagulants used for HIT type II in pulmonary thromboendarterectomy, and the potential of cangrelor in conjunction with UFH to be a favorable option for patients in similar clinical scenarios.