Comparison of Myocardial Metabolism and Apoptosis in Patients Undergoing CABG Operation Performed Either with Fibrillation or Cardioplegia Method

Abstract

Objective: Optimal myocardial protection during CABG operations is still debatable. In this study we compared hemodynamic data, myocardial oxygen extraction, lactate production and presence of apoptosis in transmural biopsy specimens in operations performed either with intermittent aortic cross-clamping with fibrillation (IAC) or with cardioplegic cardiac arrest (CCA) method. Methods: Following Ethics Committee approval, consecutive patients with normal ventricular function and without any comorbid disease other than regulated hypertension and/or type-2 DM were included in the study (IAC group n=13, CCA group n=8). Hemodynamic data, serial CK-MB values and ECG changes at intermittent time points were recorded till postoperative 24 hours. Myocardial oxygen extraction and lactate production were calculated from the blood samples withdrawn from the aortic root and the coronary sinus cannula before total CPB, during cross-clamping and following removal of cross-clamp. Transmural biopsy specimens obtained before total CPB and cessation of CPB were analyzed for apoptosis. Results: Demographic and intraoperative hemodynamic variables were similar. Pre ischemic and post ischemic myocardial oxygen extraction and lactate production values were comparable in both groups. Seven patients in IAC and one patient in CCA group needed low dose inotropic support during early postoperative period. Any evidence of apopitosis was not found in both groups. Conclusion:This study shows that for low risk CABG procedures, IAC and CCA methods were not superior to each other in protecting the myocardium from ischemic injury with respect to myocardial oxygen extraction, lactate production and presence of apoptosis.