Estabelecimento do ponto de corte da troponina I como marcador de infarto do miocárdio em cirurgia de revasculariza??o miocárdica

摘要

Background: Despite modern intraoperative myocardial protection, 5 to 15 percent of patients undergoing coronary artery bypass grafting (CABG) undergo to a perioperative myocardial infarction (MI). The diagnosis of MI after cardiac surgery is difficult because of the nonspecific ST-T wave abnormalities on EKG and the usual elevation of creatine kinase (CK) levels postoperatively. Also, experience with troponin I (TnI), a more sensitive serum marker of cardiac injury, is limited in this clinical set. This study assessed the threshold levels of trponin I (TnI) for diagnosis of perioperative MI in CABG. Methods: TnI was analyzed in blood samples obtained preoperatively and 6, 12 and 24 hours postoperatively, in 147 consecutive patients undergoing to CABG, using standardized operative procedures and myocardial protection. The serum concentration of TnI was determined technique (upper normal level 9.15 ng/mL (Odds Ratio: 36, confidence interval: 5-283; p < 0.001), in diagnosing perioperative MI were 94% and 68%, respectively. Conclusions: TnI is, at least, as good as CK-MB for early diagnosis of myocardial damage. In our study. TnI levels grater than 9.15 ng/mL, within 12 hours after CABG, shows the highest values for both diagnosis efficacy and ROC curve analysis.