Postoperative troponin-T predicts prolonged intensive care unit length of stay following cardiac surgery

Objective: To evaluate the use of postoperative cardiac troponin T (cTnT) for the prediction of prolonged intensive care unit length of stay following cardiac surgery. Design: Prospective, single-center, observational cohort study of patients following cardiac surgical procedures. The enrollment period was from October through December 2000. Patients were enrolled on admission to the intensive care unit and followed until hospital discharge. Setting. The cardiac surgical intensive care unit of the Massachusetts General Hospital. Patients. A total of 222 consecutive patients were enrolled. Interventions. None. Measurements and Main Results. Perioperative clinical factors and serum concentrations of cTnT measured every 8 hrs after surgery were recorded. These clinical factors and the results of serum cTnT measurement were correlated with the need for prolonged intensive care unit length of stay (defined as >24 hrs). Univariable analysis identified factors predictive of prolonged intensive care unit length of stay. Stepwise logistic regression identified independent predictors of prolonged intensive care unit length of stay. Multiple linear regression was used to explore the direct relationship between cTnT concentrations at several postoperative time points and intensive care unit length of stay. At each time point assessed, cTnT concentrations from patients requiring a prolonged intensive care unit length of stay were significantly higher (all p < .001) than in those individuals with normal length of stay. In contrast, creatine kinase isoenzymes were not significantly different between patients with normal or prolonged intensive care unit length of stay. Multivariable analysis demonstrated that an immediate postoperative cTnT concentration 1.58 ng/mL was the strongest predictor of a prolonged intensive care unit length of stay (odds ratio, 5.6; 95% confidence interval, 2.9-10.8). Multiple linear regression analysis revealed that intensive care unit length of stay increased by 0.32 days with each incremental 1.0 ng/mL increase in cTnT measured at 18-24 hrs postprocedure. Conclusions. Elevated postoperative cTnT concentrations can prospectively identify patients requiring prolonged intensive care unit length of stay after cardiac surgery.