Anticoagulation of patients with heparin-induced thrombocytopenia in cardiac surgery

Abstract

The hazards of heparin-induced thrombocytopenia in patients undergoing cardiac surgery are increasingly being appreciated. Decision-making in favor of an alternative anticoagulation strategy in the complex perioperative setting of cardiac surgery, however, remains a predicament. The aim of this review is to provide an overview of the current strategies for the treatment of patients with heparin-induced thrombocytopenia in this setting. With the introduction of the direct thrombin inhibitors, approved alternative anticoagulants for pre- and postoperative thrombosis prophylaxis are available. Regarding intraoperative anticoagulation, convincing evidence suggests that, if no heparin-induced thrombocytopenia antibodies are present, anticoagulation during cardiopulmonary bypass can be safely performed with unfractionated heparins when the administration of heparin is restricted to the short period of cardiopulmonary bypass. If antibodies are present and surgery cannot be postponed, however, an alternative anticoagulation strategy must be employed. All the currently used strategies, such as administration of direct thrombin inhibitors or the combination of unfractionated heparin with antiplatelet agents, involve three problems: (1) strategies are 'off-label' in this indication; (2) no antidote is available, implying the potential risk of severe hemorrhagic complications; and (3) assays for point-of-care monitoring are not approved or available. If possible, surgery should be delayed until antibody titers are negative. However, if antibodies are present and surgery cannot be postponed, in a synoptic approach, the anticoagulation protocol and the surgical strategy must be adjusted to the condition of the patient and the experience of the center in order to reduce the risk of these 'off-label' strategies.