Long-term outcomes of heparin-induced thrombocytopenia after cardiac surgery

Heparin-induced thrombocytopenia (HIT) after cardiac surgery may lead to greater morbidity and mortality than predicted preoperatively. The aim of this study is to assess long-term outcomes of patients surviving HIT after cardiac surgery.

Single-institution, retrospective study of adult patients who underwent cardiac surgery between 2011 and 2023 and developed HIT postoperatively. The institutional Society of Thoracic Surgeons database and electronic medical record were integrated with longitudinal data from phone questionnaires. HIT was defined by combined clinical (4Ts score) and serologic manifestations: a platelet decrease >50% from preoperative baseline, a high optical density positive heparin-PF4 antibody test, and a positive serotonin release assay.

We identified 88 of 11,658 patients (0.8%) with HIT after cardiac surgery. The majority were male (74%), white (73.8%), and with a mean age of 65.6 ± 11.6 years. Seventy-seven (87.5%) survived to discharge, had a 4Ts score of 5 [4-6], and 58 (75.3%) were discharged on oral anticoagulation, with only 22 (28.6%) receiving treatment for the past 3 months, for a median of 1.3 [0.8-4.5] years. Median length of stay was 24 [17-35] days and length of follow-up was 4.6 [0.3-12] years. Readmission occurred in 70.1% (n = 54) of patients, with an average of 3 [1-6] readmissions/patient. Causes of death during follow-up included cardiac (n = 7, 24.1%), infectious (n = 6, 20.7%), or neurologic events (n = 5, 17.3). Ten-year survival probability was 48%.

Patients who develop HIT after cardiac surgery have an overall poor prognosis even after hospital discharge. In addition to prolonged hospitalization, patients experience further complications leading to frequent early readmissions and elevated mortality in the long-term.