EARLY CHANGES IN REGIONAL AND GLOBAL LEFT-VENTRICULAR FUNCTION AFTER AORTIC-VALVE REPLACEMENT - COMPARISON OF CRYSTALLOID, COLD BLOOD, AND WARM BLOOD CARDIOPLEGIAS

Background The clinical effects of different cardioplegic methods on l eft ventricular (LV) function have not been fully elucidated, particul arly in the setting of myocardial hypertrophy. Methods and Results Six ty-four patients (mean age, 62+/-12 years; 41 men, 23 women) who were undergoing elective aortic valve replacement (stenosis, 49; regurgitat ion, 15; concomitant coronary artery bypass grafting, 22), with LV mas s index 230+/-70 g/m(2), were randomized to the following groups: ante grade crystalloid cardioplegia (CCP, 21 patients), antegrade/retrograd e cold blood cardioplegia (CBP, 23 patients), or continuous retrograde warm (37 degrees C) blood cardioplegia (WBP, 20 patients). Mean aorti c cross-clamp and cardiopulmonary bypass times were 100+/-20 and 126+/ -24 minutes. Positive inotropic drug therapy was required postoperativ ely in 9 patients after CBP, 14 after CCP, and 18 after WBP. Periopera tive LV function was assessed using transesophageal M-mode echocardiog raphy, combined with high-fidelity LV pressure recording and thermodil ution cardiac output, before bypass and 0.5, 1, 3, 6, 12, and 20 hours after cross-clamp removal. There was a similar fall in LV peak circum ferential wall stress at constant LV end-diastolic dimension in each g roup after aortic valve replacement. The increase in contraction veloc ity was significant from 0.5 hour with CBP; however, no significant in crease occurred until 12 hours with CCP and until 20 hours with WBP. T he rate and extent of LV pressure fall and early diastolic filling rat e both increased with CBP, and only in this group did ventricular coor dination improve. LV stroke work index was maintained with CBP through out the postoperative period with less inotropic support than with the other two methods. Conclusions In the hypertrophied LV, CBP offers th e best preservation of myocardial physiological response and ventricul ar function with less inotropic support.