CASE 1–2015

The Triple HIT: Perioperative Management of Heparin-Induced Thrombocytopenia Using Plasma Exchange, Intravenous Immunoglobulin, and Protamine Infusion for Left Ventricular Assist Device Implantation

Heparin-induced thrombocytopenia (HIT) is a serious complication in patients exposed to heparin, leading to thrombocytopenia and, potentially, thrombosis. This disorder is challenging in cardiac surgery when anticoagulation for cardiopulmonary bypass is required. Herein a patient with HIT who had active thrombosis and successfully underwent urgent left ventricular assist device implantation managed with plasma exchange, intravenous immunoglobulin, and protamine infusion is described. These therapies reduce the immune response to heparin and minimize thrombosis when heparin reexposure is planned. These approaches to perioperative management of HIT represent an attractive alternative to the use of non-heparin anticoagulants in the cardiac and vascular surgical population.

High-dose IVIG plus cangrelor platelet "anesthesia" during urgent heparin-CPB in a patient with recent SRA-negative HIT-thrombosis with persisting platelet-activating antibodies

In a high-risk patient with subacute heparin-induced thrombocytopenia (HIT) type A (platelet count recovery following acute HIT but with persisting platelet-activating antibodies), in whom urgent cardiac surgery was required, a key clinical question arose: could intraoperative heparin be given safely with "platelet anesthesia" provided with high-dose intravenous immunoglobulin (IVIG) plus cangrelor (ultra-short-acting antiplatelet agent)? This approach proved successful, without unexpected postoperative thrombocytopenia or thromboembolism. In vitro studies confirmed that both IVIG and cangrelor contributed to perioperative inhibition of HIT antibody-induced platelet activation. Interestingly, despite the patient testing strongly positive in 4 HIT immunoassays (latex immunoturbidimetric assay and 3 enzyme-immunoassays), the serotonin-release assay (SRA) was consistently negative. Nevertheless, platelet-activating HIT antibodies were detectable using modified (platelet factor 4-enhanced) SRA. Our protocol of heparin rechallenge following IVIG/cangrelor provides both intraoperative and early postoperative inhibition of HIT antibody-induced platelet activation and is applicable to patients with circulating functional HIT antibodies requiring urgent heart surgery, including those with "SRA-negative HIT."

The use of cangrelor with heparin for left ventricular assist device implantation in a patient with acute heparin-induced thrombocytopenia

Background

Optimal anticoagulation strategy for cardiopulmonary bypass (CPB) in end-stage heart failure patients with heparin-induced thrombocytopenia (HIT) requiring left ventricular assist device (LVAD) implantation remains uncertain. Presently, there are no large-scale randomized studies comparing outcomes of alternative anticoagulation strategies for CPB in this patient population. A novel antiplatelet agent – cangrelor, which is a potent P2Y12 inhibitor with robust antiplatelet efficacy, rapid reversibility, and measurable drug effect, has become available since 2015. Intraoperative anticoagulation for CPB using cangrelor with heparin has not been reported before.

Case presentation

We report the case of a 47-year-old male with ischemic cardiomyopathy and acute HIT, who underwent an urgent LVAD implantation using cangrelor with heparin for anticoagulation on CPB. This novel strategy resulted in satisfactory anticoagulation for CPB without perioperative thromboembolic events or major bleeding requiring reoperation.

Conclusions

Cangrelor with heparin was an effective anticoagulation strategy for CPB in this critically ill patient with acute HIT requiring an urgent LVAD implantation. Further studies are warranted to evaluate its efficacy and replicability in other patients with acute or subacute HIT who require urgent cardiac surgery.

Argatroban and Bivalirudin for Perioperative Anticoagulation in Cardiac Surgery

Argatroban and bivalirudin are used as replacement anticoagulants for heparin. The authors review clinical studies for these drugs in the perioperative setting of cardiac surgical patients including extracorporeal management and mechanical support therapy.

Challenging Argatroban Management of a Child on Extracorporeal Support and Subsequent Heart Transplant

A 6-year-old child developed heparin-induced thrombocytopenia while on extracorporeal life support. Hours after a difficult transition from heparin to argatroban for anticoagulation therapy, the child underwent heart transplantation. Intraoperative management was plagued with circuit thrombus formation while on cardiopulmonary bypass and subsequent massive hemorrhage after bypass. We review the child’s anticoagulation management, clinical challenges encountered, and review current literature related to the use of argatroban in pediatric cardiac surgery.