Does postoperative heparin-induced thrombocytopenia worsen outcomes following cardiac surgery? A meta-analytic review

Abstract Background Heparin-induced thrombocytopenia (HIT) after cardiac surgery is a life-threatening complication despite the low reported incidence. The impact of HIT on perioperative outcomes in cardiac surgery remains controversial, with limited and conflicting evidence regarding its effects on cardiopulmonary bypass time, length of hospital stay, complication rates, and mortality. Our meta-analysis aims to clarify the influence of postoperative HIT on outcomes in cardiac surgery. Methods We systematically searched PubMed, Embase, and Cochrane Library to identify studies comparing outcomes in patients with and without postoperative HIT after cardiac surgery. Pooled odds ratios (ORs) and mean differences (MDs) with 95% confidence intervals (CIs) were calculated using a random effects model. Heterogeneity was assessed with I 2 statistics. R software was used for statistical analysis. Results Nine studies encompassing 266,099 cardiac surgery patients were included, among whom 1,204 patients (0.45%) were diagnosed with HIT postoperatively. The pooled incidence of HIT was 1.68% [95% CI 0.13–4.88; Prediction Interval 0.00–20.85]. HIT was associated with higher in-hospital mortality [OR = 2.57; 95% CI 1.02–6.46; p < 0.0001], longer hospital stay [MD 10.02 days, 95% CI 3.87 to 16.17, p = 0.001], increased thromboembolic events [OR 5.13, 95% CI 2.10 to 12.53, p < 0.01], and stroke [OR 2.33, 95% CI 1.40 to 3.89, p < 0.01]. However, cardiopulmonary bypass time and postoperative complications including 30-day mortality, acute limb ischemia, pulmonary embolism, renal complications, renal replacement therapy, and sepsis did not differ significantly between HIT and non-HIT groups. Conclusions HIT after cardiac surgery is associated with higher in-hospital mortality, longer duration of hospital stay, increased thromboembolic events, and stroke. Despite consistent signals of harm, the very low certainty of evidence necessitates cautious interpretation and highlights an urgent need for higher-quality prospective studies. Systematic review registration PROSPERO CRD420251175827