ANTEGRADE RETROGRADE CARDIOPLEGIA IN ARTERIAL BYPASS-GRAFTING - METABOLIC RANDOMIZED CLINICAL-TRIAL

The metabolic effects of combined antegrade/retrograde and antegrade c ardioplegia on myocardial protection were evaluated and compared in 30 patients who underwent myocardial revascularization. All patients had three-vessel coronary artery disease, and the revascularization was d one with exclusive use of arterial grafts (internal mammary artery, ga stroepiploic artery). Myocardial protection consisted of oxygenated cr ystalloid cardioplegia, topical slushed ice, and moderate systemic hyp othermia (34 degrees C). The patients were randomly separated into two groups: group A (n = 15), who received antegrade cardioplegia, and gr oup A/R (n = 15), who received combined antegrade/retrograde cardiople gia. There was no significant difference between the two groups concer ning preoperative and intraoperative data. After the first dose of car dioplegia, right ventricular temperature was significantly lower in gr oup A/R (15 a 2 degrees versus 19 a 5 degrees C; p < 0.05), and there was no significant difference between the two groups in left ventricul ar temperature. Coronary sinus blood samples were obtained before bypa ss and 5, 10, and 15 minutes after reperfusion; there was no differenc e between the two groups concerning lactates, superoxide dismutase, an d gluthatione peroxidase. After reperfusion, malondialde-hyde levels i ncreased significantly in group A and there was no change in group A/R , with a significant difference between the two groups (at 10 minutes after reperfusion, 0.80 +/- 0.20 versus 0.53 +/- 0.16 mu mol/L; p < 0. 05). Right and left ventricular myocardial biopsies were performed bef ore bypass and 15 minutes after reperfusion; there was no significant difference between the two groups concerning adenosine triphosphate an d creatine phosphate myocardial concentrations. After reperfusion, spo ntaneous recovery of heart activity without defibrillation occurred in 14 patients in group A/R and in 9 patients in group A (p < 0.05); the re was no atrioventricular block iri group A/R and 26% in group A (p < 0.05). Postoperative release of creatine kinase isoenzyme was higher in group A than in group A/R (6 postoperative hours, 21 +/- 12 versus 15 +/- 5 mu g/L; 12 postoperative hours, 20 +/- 14 versus 12 +/- 5 mu g/L; p < 0.05). We conclude that combined antegrade/retrograde cardiop legia provides better and more homogeneous myocardial protection than does antegrade cardioplegia in patients with three-vessel coronary art ery disease who undergo myocardial revascularization with exclusive us e of arterial grafts.