Novel Use of Cangrelor with Heparin During Cardiopulmonary Bypass in Patients with Heparin-induced Thrombocytopenia who Require Cardiovascular Surgery: A Case Series

Semin Thorac Cardiovasc Surg. 2019 Oct 11. [Epub ahead of print]

Optimal anticoagulation strategy during cardiopulmonary bypass (CPB) remains uncertain in patients with heparin-induced thrombocytopenia (HIT) who require urgent/emergent cardiac surgery. We describe our strategy and experience with utilizing cangrelor in combination with heparin for anticoagulation during CPB in patients with different phases of HIT undergoing a wide range of urgent/emergent cardiovascular surgery. Cangrelor is an intravenous direct-acting P2Y12 platelet receptor antagonist that achieves therapeutic effect and eliminates rapidly. Its antiplatelet activity is unaffected by stagnation of blood, nor is it influenced by patient’s sex, age, renal status, or hepatic function. Our institutional alternative intraoperative anticoagulation strategy for HIT patients is to administer cangrelor with a loading dose of 30 μg/kg, followed by continuous infusion of 4 μg/kg/min throughout CPB via a dedicated intravenous access. VerifyNow P2Y12 reaction unit point-of-care assay is utilized to monitor platelet inhibition throughout surgery. Cangrelor infusion is discontinued 10 minutes prior to heparin reversal with protamine. Ten urgent/emergent cardiovascular surgeries were performed at our institution using cangrelor with heparin for anticoagulation during CPB, and the majority were pulmonary thromboendarterectomy (60%). HIT was confirmed in 3 cases, and was suspected in 4 which was found to be negative after the operation. One case of subacute B HIT and 2 cases of remote HIT were included in this series. This novel alternative intraoperative anticoagulation strategy was well tolerated by all patients. There was no serious postoperative thrombotic event nor major postoperative bleeding complication that required re-operation. One death occurred in a patient with advanced intracardiac malignancy, whose life support was ultimately withdrawn postoperatively. Median postoperative intensive care unit stay was 7.2±5.5 days, while median postoperative hospital stay was 16.3±10.8 days. In patients with various phases of HIT who require urgent/emergent on-pump cardiovascular surgery, the use of cangrelor with heparin may be a convenient, safe, and effective alternative intraoperative anticoagulation strategy providing acceptable outcomes.