Postoperative serum troponin T concentration in patients undergoing aortic valve replacement does not predict early postoperative outcome

Abstract

Background: The measurement of serum cardiac troponin T concentration (cTnT) after aortic valve replacement (AVR) provides the opportunity to assess the degree of myocardial damage and may have some prognostic value.

Aim: To determine whether elevated troponin level is related to patient outcome.

Methods: We investigated patient outcome and postoperative serum concentration of troponin T in 79 patients who underwent AVR. Serum levels of cTnT were measured within 24 h of AVR. We searched for the occurrence of subsequent adverse events i.e. requirement for intraaortic ballon pump (IABP) or inotropic support, prolonged Intensive Care Unit (ICU) stay, and in-hospital death.

Results: Serum concentration of cTnT after AVR increased significantly compared to the preoperative value. We found significant positive correlations between aortic cross-clamp time (r = 0.23, p = 0.04), cardiopulmonary bypass time (r = 0.4,p = 0.00029), duration of the surgery (r = 0.30, p = 0.008), and postoperative cTnT level. Three (4%) patients required IABP support, 37 (46%) patients required inotropic support, and 11 (14%) patients had a prolonged ICU stay (> 48 h). Thirty eight (48%) patients required either inotropic support or IABP insertion. At least one adverse event occurred in 44 (56%) patients. Median postoperative serum cTnT concentration was 0.31 ng/mL (interquartile range 0.23–0.60 ng/mL). We failed to find a statistically significant difference in postoperative cTnT level between patients with and without adverse events. According to multiple logistic regression analysis, the postoperative serum level of troponin T was not independently associated with adverse patient outcome. Diabetes mellitus, patient age and left ventricular ejection fraction below 50% were significant independent predictors of adverse events after AVR. The area under receiver operating curve (AUROC) for postoperative serum troponin T concentration as a determinant of various adverse outcomes was never significantly different from 0.50.

Conclusions: Serum cTnT concentration is frequently — if not universally — elevated after AVR. Serum level of troponin T measured on the first postoperative morning is a poor predictor of patient outcome after AVR and should not be relied on when planning postoperative care.