WHICH MYOCARDIAL PROTECTION FOR ISOLATED AORTIC-VALVE REPLACEMENT - APROSPECTIVE CLINICAL-STUDY OF 3 CARDIOPLEGIAS

Isolated stenosis of the aortic valve leads to left ventricular hypert rophy which makes myocardial protection difficult during cardiac surge ry and the choice of optimal cardioplegia remains controversial. The a uthors compared three protocols of cardioplegia in patients operated f or isolated aortic stenosis with left ventricular lar hypertrophy. Six ty consecutive patients with these criteria were randomly attributed t o one of the three following groups (20 in each group): cardioplegia w ith continuous warm blood; cardioplegia with intermittent cold blood w ith warm reperfusion; cardioplegia with intermittent cristalloid using SLF11 solution. The preoperative data was comparable in three groups. There were no deaths. Patients undergoing cardioplegia with warm bloo d came off cardio-pulmonary bypass more quickly (15 mn vs 21 mn for th e other groups, p = 0.03). Cristalloid cardioplegia was associated wit h major acidosis in coronary sinus blood when the aorta was declamped (7.11 vs 7.38 for cardioplegia with cold blood and 7.39 for cardiopleg ia with warm blood, p < 0.0001) but with a low postoperative CPK-MB ri se. Cardioplegia with cold blood induced higher CPK-MB liberation than the other forms of cardioplegia (at H-, 63 mcg/L vs 33 for warm blood and 45 for cristalloid cardioplegia, p = 0.0019). None of the protoco ls tested prevented myocardial lactate production at aortic declamping , Cardioplegia with warm blood offers therefore the best protection fo r hypertrophied myocardium during simple aortic valve replacement but it does not maintain strictly aerobic metabolism.