Serum concentrations of Troponin I in the detection of acute myocardial infarction in coronary artery bypass grafting <b>[Abstract in English]</b>

Authors

  • Rafael B. Nascente
  • João C. V. C. Guaragna
  • Franca S. A. Spiandorello
  • Raquel Melchior
  • Gustavo Werutski
  • Eduardo Azevedo
  • João B. Petracco
  • Luis C. Bodanese

Abstract

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 < 0.5 ng/mL). Patients were eligible for enrollment if they had one of the following criteria: new Q-wave or left bundle-branch block and a more than three times elevation of creatine kinase MB (CK-MB); non EKG changes and more than eight times elevation of CK-MB.
Results: Eighteen (12%) patients had perioperative MI. The mean (± Standart Deviation) Tnl levels at 6, 12 and 24 hours were, respectively, 13 (±14) ng/mL, 57 (±32) ng/mL, 45 (±33) ng/mL, in MI group and 8 (±11) ng/mL, 12 (±19) ng/mL, 8 (±20) ng/mL, in non MI group. Tnl values were statistically different at 12 and 24 hours. Also, tnl levels were significantly elevated above their threshold level within 12 hours after CABG (ROC curve: 0.89). Sensitivity and specificity of Tnl, at fixed cut-off level of > 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.
KEY WORDS: TROPONIN I; MYOCARDIAL INFARCTION; CORONARY ARTERY BYPASS; MYOCARDIAL REVASCULARIZATION.

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Published

2006-10-17

How to Cite

Nascente, R. B., Guaragna, J. C. V. C., Spiandorello, F. S. A., Melchior, R., Werutski, G., Azevedo, E., Petracco, J. B., & Bodanese, L. C. (2006). Serum concentrations of Troponin I in the detection of acute myocardial infarction in coronary artery bypass grafting <b>[Abstract in English]</b>. Scientia Medica, 15(3). Retrieved from https://revistaseletronicas.pucrs.br/index.php/scientiamedica/article/view/1560

Issue

Vol. 15 No. 3 (2005)

Section

Original Articles

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