Cardiopulmonary Bypass Without Heparin

Abstract

Due to familiarity, short half-life, ease of monitoring, and the availability of a reversal agent, heparin remains the anticoagulant of choice for cardiac operations requiring cardiopulmonary bypass (CPB). However, occasionally patients require CPB but should not receive heparin, most often because of acute or subacute heparin-induced thrombocytopenia (HIT). In these cases, if it is not feasible to wait for the disappearance of HIT antibodies, an alternative anticoagulant must be selected. A number of non-heparin anticoagulant options have been explored. However, current recommendations suggest the use of a direct thrombin inhibitor such as bivalirudin. This review describes the use of heparin alternatives for the conduct of CPB with a focus on the direct thrombin inhibitors.

Combination of aptamer and drug for reversible anticoagulation in cardiopulmonary bypass

“…For comparison, we also similarly evaluated the effects of bivalirudin, a direct thrombin inhibitor that is occasionally employed as an alternative for CPB anticoagulation in patients with severe contraindications to UFH such as HIT 2,6,44 . However, bivalirudin is used very cautiously because its use during CPB surgery is associated with a notable risk of clotting in areas prone to blood pooling such as the operative field or CPB circuit 2,6,44 . Consistent with its weaker potency, even at supra-therapeutic concentrations as high as 36.7 μM, bivalirudin only extended the TEG clotting time to 34.3 ± 4.1 minutes (Fig.…”

“…While the direct thrombin inhibitor bivalirudin has been used as an alternative CPB anticoagulant to UFH in patients with proven or suspected HIT, bivalirudin requires continuous infusion owing to its 25-minute half-life, and its use during CPB carries a well-known risk of clot formation in blood that becomes stagnant in the operative field or in the CPB circuit 2,6,44 . Although bivalirudin is approved for CPB in Canada, it has not received approval by the U.S. FDA or European Medicines Agency even for patients with HIT.…”

Plasma exchange for heparin‐induced thrombocytopenia in patients on extracorporeal circuits: A challenging case and a survey of the field

“…The incidence of HIT ranges from 0.1% to 5% of all patients who have received heparin and patients with anti‐PF4‐heparin antibodies is frequently encountered in the setting of cardiac surgery . While consensus for managing HIT in patients needing nonurgent cardiac surgery with CPB is uniform, guidelines for management of patients with HIT requiring urgent CPB are not firmly established . Depletion of anti‐PF4‐heparin antibodies with TPE followed by short‐term heparin exposure is a safe and effective anticoagulation strategy for patients with acute HIT who require urgent cardiac surgery with CPB …”

“…3,30,31 While consensus for managing HIT in patients needing nonurgent cardiac surgery with CPB is uniform, guidelines for management of patients with HIT requiring urgent CPB are not firmly established. 32 Depletion of anti-PF4-heparin antibodies with TPE followed by shortterm heparin exposure is a safe and effective anticoagulation strategy for patients with acute HIT who require urgent cardiac surgery with CPB. 14,15,20,21,33 The current case report provides additional support for the role of TPE in cases of HIT requiring urgent CPB and supports the use of anti-PF4-heparin antibody OD to guide safe short-term heparin re-exposure similar to previous accounts.…”

Management of refractory bleeding post-cardiopulmonary bypass in an acute heparin-induced thrombocytopenia type II renal failure patient who underwent urgent cardiac surgery with bivalirudin (Angiox®) anticoagulation

“…It is characterised by a 30-50% reduction in platelet count and is often associated with life-threatening venous or arterial thrombotic complications. 1,2 Of importance to this paper is the contraindication of UFH for acute HIT patients requiring cardiac surgery and dialysis.…”