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were calculated from the blood samples withdrawn from the aortic root and the coronary sinus cannula before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.
Keywords: cardiac surgery, myocardial protection, oxygen extraction, lactate production