Antegrade versus antegrade / retrorade cardioplegia for myocardial protection in patients undergoing coronary artery bypass grafting

Objective: Nonhomogeneous distribution of cardioplegia antegradely in severe coronary artery stenosis and evolving acute myocardial infarction has been demonstrated experimentally. Administration of cardioplegia retrogradely causes homogeneous distribution and offers a good alternative for myocardial protection. Methods: Thirty five consecutive patients with three vessel-disease undergoing elective coronary artery bypass grafting were prospectively randomized to receive either antegrade cold blood cardioplegia alone (Group A, n: 17) or antegrade/retrograde cold blood cardioplegia (Group B, n: 18). The patients in group B received cardioplegia half dose antegradely and then the other half dose was given retrogradely. In both groups, following the induction dose of cold blood cardioplegia, 500 ml cold blood maintenance cardioplegia every 20 minutes and terminal warm blood cardioplegia were applied before the removal of the aortic cross clamp antegradely in group A and retrogradely in group B. Results: Baseline patients characteristics did not differ in both groups. Myocardial temperature measured following the induction cardioplegia; was significantly higher in group A than in group B (p<0.05). After 10 minutes of reperfusion, the rise in myocardial oxygen extraction and myocardial lactate extraction was higher in group A than in group B (p<0.02). CK-MB and Troponin-T levels at the postoperatively 12th hour were significantly higher in group A than in group B (p<0.05). Eight patients in group A, and 4 patients in group B inotropic support was used because of the low cardiac output (p: NS). However, when compared the inotropic score of the two groups, it was significantly higher in group A than in group B (2.1$\pm$0.6 in group A, 1.2+$\pm$0.5 in group B p<0.04). In four patients in group A, 5 patients in group B atrial fibrillation, and in 5 patients in group A, 2 patients in group B ventricular extrasistole were observed (p:NS). Conclusion: Antegrade/retrograde cardioplegia performs better protection and faster recovery than the antegrade cardioplegia alone.