2026 Eastern States Conference

Title: Outcomes associated with anticoagulation in cardiothoracic surgery patients with post-operative thrombocytopenia
Authors: Nada Daoud, PharmD; Corinne Whiteman, PharmD, BCCCP; Karishma Patel, PharmD
Objective: Audience members will be able to describe the incidence of heparin-induced thrombocytopenia (HIT) in cardiothoracic (CT) surgery patients.
Self-assessment question: True or False? Patients who develop thrombocytopenia while on heparin should be switched to a non-heparin anticoagulant regardless of their 4T score.
Background: When HIT is suspected, a 4T score is calculated and heparin is switched to a non-heparin anticoagulant. This study aimed to assess the incidence of HIT in post-operative CT surgery patients and evaluate the safety of argatroban.
Methods: This is a retrospective, single-center cohort study with data collected from January 2020 to July 2025. Post-operative CT surgery patients were eligible for inclusion if they had a platelet factor 4 enzyme-linked immunosorbent assay (PF4 ELISA) and/or serotonin release assay (SRA) HIT panel ordered within 30 days after surgery. Patients were excluded if they did not receive anticoagulation, had a prior history of HIT, were less than 18 years of age, or were pregnant. The primary outcome was the incidence of SRA-confirmed HIT. Secondary outcomes included intensive care unit (ICU) and hospital length of stays, 90-day mortality, time to therapeutic activated partial thromboplastin time (aPTT), and incidence of thrombocytopenia. Safety outcomes were the incidence of hepatotoxicity, bleeding, and thrombosis. Categorical data was reported as percentages, and continuous data was expressed as medians with interquartile ranges.
Results: A total of 54 patients were reviewed for eligibility, and 28 patients were included. Twenty-four hours after a HIT panel was ordered, 11 patients were not on anticoagulation, 11 were on heparin, and 6 were on argatroban. One patient met the primary outcome of having SRA-positive HIT (3.6%). Coronary artery bypass grafting (CABG) was the most common type of CT surgery in all three groups. Patients in the heparin group had longer hospital length of stays (23.7 [28.6] days) compared to those in the argatroban (17.3 [24.5] days) and no anticoagulation groups (19.5 [17.1] days). Patients on argatroban experienced more hepatotoxicity (83% vs. 75% vs. 67%) and bleeding events (100% vs. 63% vs. 83%) than those on heparin and no anticoagulation.
Conclusions: The low incidence of SRA-confirmed HIT suggests that post-CT surgery patients may develop thrombocytopenia due to risk factors other than heparin use. Switching from heparin to a non-heparin anticoagulant may be inappropriate in patients with a low 4T score and result in adverse events, as patients on argatroban experienced more hepatotoxicity and bleeding. Larger studies are needed to further define the incidence of HIT in CT surgery patients and the impact of argatroban on patient outcomes.