Cangrelor and Heparin for Left Ventricular Assist Device Implantation in a Patient with Heparin-Induced Thrombocytopenia

Abstract

Introduction Perioperative anticoagulation in patients with heparin-induced thrombocytopenia (HIT) requiring cardiopulmonary bypass (CPB) presents a clinical challenge due to high risk of intravascular thrombosis. Alternative anticoagulants have been used but carry their own risks. We report the successful use of Cangrelor, a P2Y12 platelet receptor antagonist, with heparin during left ventricular assist device (LVAD) implantation. Case Report A 25-year-old female with dilated cardiomyopathy due to dermatomyositis and Turner's syndrome and left ventricular thrombus on apixaban, was admitted to our institution with worsening dyspnea. She had a left lower lobe segmental and subsegmental pulmonary embolus and was started on heparin infusion. Over a few days, her platelet count decreased from 278K to 8K and she developed a subclavian and internal jugular deep vein thrombosis. Given concern for HIT, she was switched to bivalirudin. Severe HIT was confirmed with an optical density of 2.8. She progressed into cardiogenic shock requiring inotrope and mechanical support. Given her hemodynamic deterioration, we proceeded with HeartMate II LVAD implant after thorough evaluation. In consultation with hematology, we utilized cangrelor and heparin to minimize platelet aggregation and thrombosis during CPB. Cangrelor has a favorable pharmacokinetic profile for use with heparin in HIT patients given its fast-onset, short half-life, and high-affinity causing aggregation. Intraoperatively, platelet reactivity units (PRUs) were measured to assess Cangrelor's activity and ensure P2Y12 antiplatelet effect with the appropriate scale. A cangrelor bolus and infusion were given before heparinization; PRU reduced from 326 to 103 (less than 208 indicates presence of antiplatelet effect). Systemic heparinization was then safely achieved with Cangrelor infusion being discontinued 10 minutes prior to heparin reversal with protamine. She was started on bivalirudin postoperatively and eventually transitioned to coumadin. Summary This case represents a novel approach of using cangrelor with heparin intraoperatively for a patient with confirmed HIT requiring urgent LVAD implantation. Cangrelor use with heparin offers a safe and effective option in surgeries requiring CPB while minimizing hematologic complications of thrombosis and bleeding.