The present study was developed to determine the early and late prognosis of patients submitted to myocardial revascularization (with or without extracorporeal circulation) and the relationship with troponin-I serum levels at the postoperative period. One hundred and eight patients were studied between December 1996 and December 1997. The serum troponin-I levels were determined by chemoluminescence (Acess - Sanofi-Pasteur) during four periods: preoperative, admission to Intensive Care Unit, first postoperative day and second postoperative day. Values below 0.1 ng/ml were considered normal. Cut-off levels for prognostic evaluation (0.5, 1.0, 2.5 and 5.0 ng/ml) were chosen. Follow-up was measured in months with the aim of construction survival curves. The only event considered was cardiac death. Serum troponin-I had a characteristic early behaviour with higher levels on the first postoperative day. When extracorporeal circulation was utilized (Group I), the levels were significantly higher but there was no correlation with ischemic or perfusion times. Perhaps the troponin-I high serum levels could be due to specific myocardial injury, i. e. coronary artery obstruction, saphenous bypass graft acute failure and so on and not due to extracorporeal circulation per se. It was also possible to determine the cut-off levels as markers of poor prognosis. Serum troponin-I higher than 2.5 ng/ml on the first postoperative day were followed by mortality rates between 33% and 50% up to 6 months of follow-up. Serum troponin-I levels were higher than normal in patients submitted to myocardial revascularization with or without extracorporeal circulation, signifying myocardial cell injury. Values close to 2.5 ng/ml on the first postoperative day alert to the necessity of more aggressive diagnostic and therapeutic measures.
Myocardial revascularization; Troponin I
