Does retrograde administration of blood cardioplegia improve myocardial protection during first operation for coronary artery bypass grafting?

Background: The objective of this study was to evaluate the value of retrograde blood cardioplegia in coronary artery bypass grafting.
Methods: In 1994 and 1995, 224 patients undergoing first-time isolated coronary artery bypass grafting were randomized to antegrade (112 patients, group 1) or retrograde (112 patients, group 2) administration of blood cardioplegia. In group 1, 76 patients were given warm cardioplegia (at 33 degrees C) and 36 had cold cardioplegia (< 20 degrees C), whereas in group 2 cardioplegia was warm in 77 patients and cold in 35. The two randomization groups had similar demographic and angiographic characteristics. The number of grafted coronary arteries averaged 2.9 +/- 0.7 in group 1 and 2.8 +/- 0.7 in group 2. Total duration of cardiopulmonary bypass (78 +/- 23 and 75 +/- 21 minutes) and of aortic cross-clamping (47 +/- 16 and 46 +/- 16 minutes), total volume of infusion of the crystalloid component of cardioplegia (988 +/- 297 and 1016 +/- 595 mL), and total duration of infusion of cardioplegia (23 +/- 10 and 22 +/- 11 minutes) were similar (p > 0.05).
Results: There was no death in group 1 and one in group 2 as a result of a pulmonary embolus, for a global early mortality of 0.45%. The numbers of perioperative myocardial infarction (5 versus 3), congestive heart failure (4 versus 5), postoperative hemorrhage (4 versus 4), and stroke (1 versus 2) were also similar (p > 0.05). Release curves of total creatine kinase, creatine kinase-MB by serum activity and mass concentration, and troponin T were not significantly different (p > 0.05) between the two groups. For the 216 patients without perioperative myocardial infarction, peak enzyme release of creatine kinase-MB at 24 hours averaged 23 +/- 22 and 20 +/- 18 IU/L, and that of troponin T averaged 1.1 +/- 1.1 and 1.3 +/- 1.5 micrograms/L at 6 hours for the antegrade and the retrograde groups, respectively (p > 0.05).
Conclusions: Our results indicate no evidence that the retrograde method of cardioplegic infusion improves myocardial protection during first operation for isolated coronary revascularization compared with the usual antegrade route.