Creatine Kinase MB, Troponin I, and Troponin T Release Patterns after Coronary Artery Bypass Grafting with or without Cardiopulmonary Bypass and after Aortic and Mitral Valve Surgery

Abstract

Perioperative acute myocardial infarction (AMI) is a serious complication of cardiac surgery, leading to increased morbidity and mortality (1). Currently, the diagnosis of AMI is based on changes in the electrocardiogram and increased release of biochemical markers. However, changes in the electrocardiogram are not sensitive and specific, whereas creatine kinase MB (CKMB) is not cardiac specific (2). The new markers troponin I and troponin T discriminate between myocardial and skeletal muscle damage (3)(4). Coronary artery bypass grafting (CABG) can be performed with or without (“off-pump”) the use of cardiopulmonary bypass (CPB), whereas valve surgery necessitates CPB. During cardiac operations with CPB, the heart is arrested and protected by cardioplegia. During this period the heart is ischemic. At the end of CPB, the heart is reperfused, and cardiac action resumes. This reperfusion after the ischemic period produces myocardial damage and eventually necrosis (5). In contrast, during off-pump CABG, the heart keeps beating, and thus reperfusion injury is avoided (6). Different types of cardiac surgery may therefore produce different release patterns of myocardial damage markers. Moreover, release of these markers in the perioperative period may be caused not only by the surgery itself, but also by myocardial infarction. The cutoff values of the cardiac markers for patients presenting with acute chest pain have already been reported (7)(8)(9). In contrast, these values are not well established for patients during and after cardiac surgery. We investigated the release patterns of the biochemical markers total CK, CKMB activity, CKMB mass, troponin I, and troponin T in patients undergoing different types of cardiac surgery without perioperative complications. After the protocol was approved by the local ethics committee and informed consent was obtained, patients scheduled for CABG with (group A: 25 males; age, 66 ± 9.8 years; 11 females; age, 68 …