Comparison of different types of cardioplegia and reperfusion on myocardial metabolism and free radical activity.

Current techniques of myocardial protection during global ischemia include hypothermia, cardioplegic arrest and controlled reperfusion. To compare different types of cardioplegia and reperfusion techniques we measured the levels of adenine nucleotides and malondialdehyde (MDA, as free radical activity) in 33 patients undergoing heart surgery. The patients were randomized in three groups according to the characteristics of cardioplegia and reperfusion: cold blood cardioplegia with unmodified blood reperfusion (control group, 11 patients), crystalloid cardioplegia and reperfusion (Hôpital Lariboisière protocol, 11 patients) and crystalloid cardioplegia with allopurinol enriched blood reperfusion (Hôpital Broussais protocol, 11 patients). Myocardial biopsy specimens were obtained before cardioplegic arrest (preischemic values), at the end of ischemia and after 30 minutes of reperfusion. Biopsy specimens were analyzed by high performance liquid chromatography for levels of adenine nucleotides and MDA. In the three groups, the preischemic values of adenine nucleotides and MDA were not significantly different. For AMP and ADP concentrations neither treatment nor biopsy-time effects appeared. ATP concentration decreased significantly with biopsy-time without specific treatment effect. For MDA concentration neither treatment nor biopsy-time effects were observed. This study suggests that there is no statistically significant difference between any of the three cardioplegia and reperfusion techniques for either ATP or MDA; the three reperfusion techniques limit the free radical activity but do not prevent the fall in high energy phosphates.