OBJECTIVE: To evaluate the importance of cardiac troponin-I serum levels in the preoperative period of patients suffering from left coronary branch obstruction but without prior cardiac events. METHOD: The cardiac troponin-I serum levels of 115 patients with obstructive coronary disease were analyzed. The ages of the patients varied between 32 and 81 years old with a mean age and standard deviation of 59.7 ± 10.5 years. The patients were divided into two groups: Group A, 41 patients suffering from left coronary branch obstruction with the degree of obstruction varying between 20% to subtotal occlusion (about 60%) and Group B, 74 patients without left coronary branch obstruction. All the patients were submitted to catheterism and no evidence of previous acute myocardial infarction (AMI) was identified. Chemoluminescence was utilized to measure the cardiac troponin-I level using the Sanofi-Pasteur Access apparatus, with values of less than 0.l nanograms per milliliter (ng/ml) considered normal. RESULTS: No association was evidenced between the degree of left coronary branch obstruction and troponin-Ic serum levels (P= 0.4617), however the average serum levels of troponin-I, in Groups A and B were 0.3841 ng/mL and 0.1711 ng/mL respectively (P=0.0324 Mann-Whitney test; OR = 4.44 95% CI 1.60 - 12.31). CONCLUSIONS: The patients of Group A have 3.44 times higher chance of presenting with myocardial injury as identified by increased cardiac troponin-I levels than Group B, independent of the degree of left coronary branch obstruction. The sensitivity of clinical suspicion of myonecrosis was relatively low (31.7%), but the specificity was high (90.5%). However the clinical importance of the documentation of myonecrosis in a determined percentage of patients with branch injury without electrocardiographic evidence is stressed. Thus, patients with left coronary branch obstruction should be quickly submitted to operative procedures, in order to avoid worsening of the myonecrosis.
Troponin I; Biological markers; Coronary disease; Myocardial ischemia; Myocardial infarction
