Heparin-induced thrombocytopenia (HIT) in patients who undergo cardiac surgery presents unique diagnostic and management challenges due to universal perioperative heparin exposure, postoperative platelet kinetics, and the high prevalence of critical illness in this population. Current guidelines do not fully address these cardiac surgery-specific features, leading to practice variation in screening, diagnosis, anticoagulation management, and perioperative planning. Consolidated, practical, and evidence-based recommendations are needed that are tailored to cardiac surgery and to temporary mechanical circulatory support after cardiac surgery.

The American Association for Thoracic Surgery Clinical Practice Standards Committee convened a multidisciplinary panel of 16 experts in cardiac surgery, hematology, critical care, anesthesiology, perfusion, and pharmacology. A comprehensive literature review was performed with medical librarian support. Using a modified Delphi methodology, the panel evaluated the evidence, developed clinical statements, and assigned a class of recommendation and a level of evidence to each recommendation.

Consensus was achieved for 32 recommendations across 5 domains: epidemiology and natural history of HIT after cardiac surgery; diagnostic evaluation, including appropriate Thrombocytopenia, Timing, Thrombosis, oTher cause (4Ts) score use, time-dependent platelet count patterns, and integration of immunoassay and functional testing; therapeutic management with nonheparin anticoagulants, including the selection of direct thrombin inhibitors, factor Xa inhibitors, and adjunctive therapies; perioperative management of patients with HIT who require cardiac surgery, including the timing of surgery, intraoperative anticoagulation strategy, and adjunctive therapies; and screening, testing, and anticoagulation strategies for patients supported by extracorporeal membrane oxygenation or temporary mechanical circulatory support after cardiac surgery. Additional best practices are included for cardiopulmonary bypass circuit management for patients with HIT.

This American Association for Thoracic Surgery Expert Consensus Document provides practical, cardiac surgery-specific guidance for the diagnosis and management of HIT across the continuum of cardiac surgical care. By addressing the complexities unique to cardiac surgery, high-risk anticoagulation environments, and extracorporeal and temporary mechanical circulatory support, these recommendations aim to improve diagnostic accuracy, standardize care, reduce complications, and support safe heparin re-exposure or alternative anticoagulation strategies when surgery is required.