The importance of troponin I in the diagnosis of myocardial infarction in the postoperative of coronary artery bypass graft surgery.
OBJECTIVE
The aim of this study is to establish a cut-off value for troponin I by correlating it to occurrence of postoperative myocardial infarction.


METHODS
180 consecutive patients with coronary disease referred for surgery were included. The mean age of the patients were 60.6 (+/-9.3) years, with 119 (66.1%) males and 61 (33.9%) females. The patients were divided into two groups: group without myocardial infarction (A)--170 patients--and with myocardial infarction (B)--10 patients.The troponin I was collected from each patient at the beginning of anesthesia and on the second postoperative day by correlating it to presence or not of postoperative myocardial infarction. StatsDirect 1.6.0 for Windows was used for statistical analysis.


RESULTS
Preoperative troponin I was 1.0 (+/-6) ng/ml as mean. Univariate logistic regression showed correlation of troponin I of the second postoperative day with myocardial infarction (P=0.0005). ROC curve was used to define the cutoff value, and 6.1 ng/ml (sensitivity=90.0%, specificity=82.1%, OR=49.8 with CI=95% 6.1- 410.4, P<0.0001) were found.


CONCLUSIONS
The chance of a patient with postoperative myocardial infarction to present troponin I equal to or higher than 6.1 ng/ml is 49.8-fold higher than the chance of a patient without infarction to present troponin I higher than this value.
Oliveira
Marcos Aurélio Barboza de
MA
São José do Rio Preto Medical School, São José do Rio Preto. m_aurelio@sbccv.org.br
Botelho
Paulo Henrique Husseni
PH
Brandi
Antônio Carlos
AC
Santos
Carlos Alberto dos
CA
Soares
Marcelo José Ferreira
MJ
Zaiantchick
Marcos
M
Machado
Maurício de Nassau
MN
Godoy
Moacir Fernandes de
MF
Braile
Domingo Marcolino
DM
D015415:Biomarkers / Q000097:blood; D001026:Coronary Artery Bypass; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011183:Postoperative Complications / Q000097:blood / Q000175:diagnosis*; D012016:Reference Values; D019210:Troponin I / Q000097:blood*
D015415:Biomarkers; D019210:Troponin I