Heparin-induced thrombocytopenia after cardiac surgery. A single-center, retrospective cohort study

Background: Cardiac surgery is a high-risk setting for heparin-induced thrombocytopenia (HIT). However, large differences in its incidence, rate of thrombotic complications, and mortality have been reported in this context. Few studies address the pharmacologic management of HIT specifically in this setting. Objectives: To describe the incidence, outcomes, and management of patients with HIT in our cohort and to compare them with patients presenting platelet factor 4/heparin antibodies but without platelet-activating capacity. Methods: A retrospective observational study was conducted over a period of 10 years and 6 months on 13,178 cardiac operations in a single high-volume cardiac surgery center. Results: HIT was diagnosed in 0.22% of patients. HIT with associated thromboembolic complications occurred in 0.04% of cases. Two deaths at 30 days were registered, both in patients with associated thrombosis. The 4T score showed a 99.9% negative predictive value. The immunoglobulin G-specific chemiluminescence test positivity rate was highly predictive of HIT. Warfarin was often started early after surgery, and although it was rarely stopped when the diagnosis of HIT was made, no new thromboembolic complications subsequently occurred. Thrombocytopenia appeared to be a poor prognostic sign, whatever the cause. Conclusion: Although rare, HIT is characterized by high mortality in this setting, especially if thrombotic complications occur. Large multicentric studies or an international registry should be created to enhance the scientific evidence on HIT diagnosis and management in this context.