Elevated troponin T concentrations in critically ill patients

Objective. To determine the incidence of troponin T elevations among a selected group of critically ill patients, to correlate these findings to electrocardiographs, and to compare troponin T-positive and T-negative patients in relation to clinical parameters. Design. Prospective study. Setting. Mixed surgical and medical intensive care unit. Patients. Thirty-four consecutive critically ill patients who were mechanically ventilated or underwent thoracic or vascular surgery. Interventions. Blood samples were collected at admission, the next morning, and 24 h after the second blood sampling. These samples were used for troponin T measurement and electrocardiographs were made when troponin T levels were elevated. Main results. Eleven of 34 patients (32%) had elevated troponin T levels, which were already present upon admission in eight out of 11 patients (73%). Most patients underwent surgery prior to ICU admission (21 of 34 patients). Significantly (P=0.0055) more troponin T-positive patients underwent acute surgery, and significantly more (P=0.045) troponin T-positive patients suffered from hypotension. Only four of the troponin T-positive patients were diagnosed as suffering from an acute myocardial infarction based on electrocardiographs. All troponin T-positive patients had coronary artery disease: nine had a history of CAD and two had actual CAD. No difference in mortality rates was observed between troponin T-positive and T-negative patients. Conclusions. An unexpectedly high percentage of included patients had troponin T elevations, which could be corroborated by electrocardiographs in only four cases suggesting that a high percentage of critically ill patients with a history of CAD suffer from clinically unrecognised (minor) myocardial damage.