Serum troponin I concentrations assessed 18-24 hours after coronary artery bypass grafting are significant predictors of early patient prognosis

Q.-L. Ma, H.-J. Wang, M.-N. Shi, J.-H. An, J. Ma, D. Yu, M. Tang, F.-W. Shi

Department of Cardiac Surgery, Second Hospital of Hebei Medical University, Shi Jiazhuang, China. drshifengwu@163.com

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• Cardiology

OBJECTIVE: Coronary heart disease (CHD) is a frequent medical condition in developed countries and is one of the most serious diseases threatening patients’ lives. Perioperative myocardial infarction is the major cause of perioperative cardiac death and cardiac arrest, but is difficult to be precisely identified by observing clinical symptoms or assessing cardiac enzyme levels or by ECG examination. Therefore, assessment of patient prognosis requires reliable predictors. In this regard, we tested the prognostic value of serum troponin I (TnI) concentrations.

PATIENTS AND METHODS: 98 patients undergoing elective simple off-pump coronary artery bypass grafting were recruited. Venous blood samples were collected within 3-5 hours, 18-24 hours, and 36-48 hours post-operation, and associations of TnI concentrations with early outcomes measures (duration of assisted ventilation, length of stay in the ICU, length of postoperative stay, administration of antihypotensive medications, use of intra-aortic balloon pump, and ECG abnormalities) were evaluated. Correlations of postoperative TnI concentrations with the outcomes measures were analyzed by using median TnI concentrations as the cut-off value.

RESULTS: TnI concentrations assessed within 18-24 hours post-operation showed significant associations with most tested outcome measures (p < 0.05 for four out of five comparisons). Furthermore, after building ROC curves, the highest AUC values (> 0.9) were also observed for TnI1 concentrations assessed within this time frame. The optimal cutoff value for TnI concentration was 1.78 ng/ml.

CONCLUSIONS: TnI concentrations assessed within 18-24 hours after elective off-pump coronary artery bypass grafting can effectively predict early patient prognosis.

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