Comparison of retrograde vs simultaneous ante/retrograde cold blood cardioplegia.

Background: To evaluate the homeostasis of myocardium during simultaneous continuous retrograde and antegrade cardioplegia vs retrograde continuous cardioplegia.
Methods: 40 patients who underwent elective operation of coronary arteries bypass grafting were randomly assigned to 2 groups: group one consisted of 24 patients who received retrograde continuous blood cardioplegia; group two consisted of 16 patients who received simultaneous continuous ante/retrograde cardioplegia. The following measurements were taken: acidosis, oxygen content, oxygen extraction and oxygen consumption; they were taken before and after cross-clamp releasing from coronary sinus effluent and from arterial line. Incidence of low cardiac output, ventricular fibrillation, raised cardiac enzymes and ischemic changes on ECG was noted.
Results: In simultaneous group such parameters as acidosis, oxygen content, oxygen extraction and myocardial oxygen consumption recovered after cross-clamping and changes of their values were respectively: 0.0005, 0.87 ml/100 ml, 0.098 and 1.4 ml/min. The same parameters didn't recovered in retrograde group and changes were respectively: 0.05 - p=0.2; 3.7 ml/100 ml - p=0.006, 0.29 p=0.006 and 7.4 ml/min - p=0.03. These changes were significant between groups.
Conclusions: Metabolic viability of myocardium measured with oxygen utilisation is better preserved with simultaneous antegrade and retrograde cardioplegia.