Incidence and outcomes of heparin-induced thrombocytopenia in patients undergoing cardiac surgery in North America: an analysis of the nationwide inpatient sample

Objectives: The objective of this study was to quantify the impact of heparin-induced thrombocytopenia (HIT) on outcomes after cardiac surgery.

Design: Retrospective analysis of national database.

Setting: United States hospitals.

Participants: Patients identified from 186,771 discharge records undergoing cardiac surgery from the Nationwide Inpatient Sample between 2009 and 2010.

Interventions: None.

Measurements and main results: Heparin-induced thrombocytopenia was diagnosed in 506 (0.3%), and secondary thrombocytopenia was diagnosed in 16,809 (8.7%). Operative mortality was 11.1% in patients with HIT compared to 4.5% for patients without thrombocytopenia (p<0.001) and 4.0% for patients with a diagnosis of secondary thrombocytopenia (p<0.001). After adjusting for baseline patient comorbidity, the strongest independent predictors of HIT in patients undergoing cardiac surgery were female gender (OR 1.4, 95% confidence interval [CI] 1.28-1.48), congestive heart failure (OR 1.8, 95% CI 1.71-1.98), cardiac insufficiency (OR 2.2, 95% CI 1.97-2.39), atrial fibrillation (OR 1.4, 95% CI 1.30-1.51), liver disease (OR 2.2, 95% CI 1.96-2.50), and chronic renal failure (OR 1.4, 95% CI 1.30-1.51). HIT was associated with significantly increased risk of major adverse postoperative outcomes including death (OR 1.5, 95% CI 1.3-1.7), stroke (OR 2.4, 95% CI 1.9-3.1), amputation (OR 7.46, 95% CI 4.0-14.0), and acute renal failure (OR 2.3, 95% CI 2.1-2.5), respiratory failure (OR 1.9, 95% CI 1.8-2.1), and need for tracheostomy (OR 2.7, 95% CI 2.3-3.1).

Conclusions: Heparin-induced thrombocytopenia is associated with a 50% increase in early mortality, and most patients with this diagnosis experience major postoperative morbidity or functional deficits.