Relationship between elevated preoperative troponin T and adverse outcomes following cardiac surgery

Background: The prognostic value of troponin T (TnT) has been demonstrated in patients following a myocardial infarction. There are limited data regarding the prognostic utility of preoperative TnT in patients undergoing cardiac surgery. The aim of the present study was to determine if elevated preoperative TnT is a predictor of more complex recovery outcomes in the cardiac surgical setting. Methods: A single preoperative TnT measurement was assessed in 696 patients undergoing isolated coronary artery bypass graft surgery. Elevated preoperative TnT levels were classified as greater than or equal to0.2 ng/mL. Preoperative, intraoperative, intensive care and postoperative events were prospectively recorded for all patients, and retrospectively reviewed for the present study. Results: Elevated preoperative TnT levels were detected in 10% (71/696) of patients. Compared to patients with normal TnT levels, elevated preoperative TnT increased the risk of mortality at 30 days (7% vs 1%, P=0.004, odds ratio (OR)=6.7) and 2 years (14% vs 3%, P<0.001, OR=5.0), and resulted in prolonged intensive care unit (ICU) stays (P<0.001) and longer postoperative hospitalization (P<0.001). Elevated preoperative TnT was also associated with an increased need for perioperative and postoperative cardiovascular support, early ischaemic change and postoperative congestive cardiac failure. In multivariate analyses preoperative TnT was a significant independent predictor of 30-day and 2-year mortality, and duration of ICU stay. Conclusions: Elevated preoperative TnT highlights a subgroup of cardiac surgical patients who are more likely to have a postoperative course with increased morbidity and mortality.