Cardiac troponin I and creatine kinase-MB release after different cardiac surgeries

Abstract

AIMS: To conduct a comparative study of cardiac troponin I (cTnI) and MB isoenzyme of serum creatine kinase (CK-MB) after different cardiac surgeries. METHODS: Consecutive cardiac operations under cardiopulmonary bypass (200 adults, 144 men, 68 ± 11 years): 67 coronary artery bypass graft (CABG), 27 aortic valve surgery, 21 mitral valve surgery, 11 thoracic aorta surgery, and 74 combined surgery. Postoperative cTnI and CK-MB were measured on admission to the ICU and at fixed time until the fifth postoperative day. RESULTS: Peak values of cTnI (median 5.8 ng/ml; interquartile range 3.6-11.9) and CK-MB (29.0 ng/ml; 15.6-60.4) were reached mainly within 18 h after the end of surgery (85% of cTnI and 95% of CK-MB highest determinations) without differences among groups. Cardiopulmonary bypass and cross-clamp time significantly correlated with markers' peak values. At multivariate analysis, mitral valve surgery showed greater cTnI, CK-MB, and their cumulative area under the curve than other isolated procedures. Thoracic aorta surgery showed lower cumulative area under the curve for both markers than CABG and combined surgery. Mitral valve surgery had significant later reduction of both markers in comparison with other procedures. No patient in mitral valve surgery group reached cTnI values in the normal laboratory range within 5 postoperative days. CONCLUSION: Release pattern of cTnI and CK-MB after heart surgery depends on the type of procedure. Mitral valve surgery was characterized by highest and longest elevation of postoperative markers' concentration. Determinants of differences in myocardial injury biomarkers and their prognostic value after valve surgery should be accurately assessed.