Impact of Blood Transfusion on Troponin I Levels and Outcomes after Cardiac Surgery: A Cohort Study.

Objectives: Increased cardiac troponin I (TI) has been suggested to be a sensitive indicator of intraoperative myocardial injury. We investigated the association of transfusion on TI levels post-surgery and outcomes in patients undergoing elective cardiac surgeries.

Methods: We conducted a retrospective review of 542 patients. Patients were divided into two groups based on TI levels at 24 hours (TI24) (> 6.5 µg/L vs. ≤ 6.5 µg/L). The impact of transfusion on TI levels was estimated using logistic regression and adjusted for using a multivariable model that included aortic cross-clamp time and preoperative ejection fraction. The effect of TI on the clinical outcomes was examined.

Results: Red blood cell (RBC) transfusion was found to be associated with high TI levels (odds ratio (OR) = 2.33, p = 0.007, 95% confidence interval (CI): 1.30-4.30). A trend was observed when aortic cross-clamp time and preoperative ejection fraction were adjusted for (OR = 2.06, p = 0.080, 95% CI: 0.90-4.70). An association was found between aortic cross-clamp time and high TI levels in the multivariable model (OR = 1.01, p = 0.028, 95% CI: 1.00-1.02). Elevated TI levels was associated with higher mortality (OR = 4.15, p = 0.017, 95% CI: 1.29-13.08), renal failure (OR = 2.99, p = 0.004, 95% CI: 1.41-6.32), and increased length of stay in-hospital (OR = 4.50, p = 0.020, 95% CI: 0.69-8.30).

Conclusions: RBC transfusion is associated with increased TI24 post-cardiac surgery and worse outcomes, albeit a confounding effect cannot be excluded. Larger studies are required to confirm these findings.