Circulating cardiac troponin T in myocardial contusion.

STUDY OBJECTIVE Myocardial contusion may induce life-threatening complications, but its diagnosis is difficult. Circulating cardiac troponin T is considered a highly sensitive and specific marker of myocardial cell injury. We investigate the value of cardiac troponin T measurement in the diagnosis of myocardial contusion. DESIGN Prospective study. SETTING Level 1 trauma center. METHODS We prospectively measured circulating cardiac troponin T and performed echocardiography and continuous Holter monitoring in patients who had suffered blunt trauma. Myocardial contusion was diagnosed in patients who fulfilled one of the following criteria: (1) an abnormal echocardiography compatible with myocardial contusion; (2) severe cardiac rhythm abnormalities; (3) severe cardiac conduction abnormalities; and (4) hemopericardium. MEASUREMENTS AND RESULTS One hundred twenty-eight patients were included and myocardial contusion was diagnosed in 29 patients. Patients with myocardial contusion had more severe trauma, experienced more frequently associated thoracic lesions, and had a lower left ventricular ejection fraction area (48 +/- 15 vs 61 +/- 10%; p < 0.001). Elevated circulating cardiac troponin T concentrations were significantly more frequent in patients with a myocardial contusion (31 vs 9%; p < 0.007). An elevated circulating cardiac troponin T concentration (> or = 0.5 microgram/L) was more accurate than MB fraction of creatine kinase (CK) (CK-MB) and CK-MB/CK ratio in the diagnosis of myocardial contusion, as shown by an area under the receiver operating characteristic (ROC) curve (AROC), which was significantly different from 0.50 (AROC = 0.69; 95% confidence interval, 0.56 to 0.80). However, this improvement was not clinically acceptable (sensitivity, 0.31; specificity, 0.91). CONCLUSIONS Circulating cardiac troponin T measurement had a slightly greater diagnostic value than usual biological parameters (CK-MB, CK-MB/CK) in myocardial contusion. Nevertheless, it was concluded that an elevated circulating cardiac troponin T concentration has no important clinical value in the diagnosis of myocardial contusion.