SIMULTANEOUS ANTEGRADE AND RETROGRADE DELIVERY OF CONTINUOUS WARM BLOOD CARDIOPLEGIA AFTER GLOBAL-ISCHEMIA

Objective: Simultaneous delivery of antegrade and retrograde cardiople gia may provide a more homogeneous distribution of cardioplegic soluti on, It may, however, increase myocardial edema and postcardioplegic my ocardial injury, The purpose of this study was to compare simultaneous antegrade-retrograde cardioplegia with antegrade cardioplegia, Method s: After 30 minutes of warm, ''unprotected,'' global ischemia, pigs we re given warm, continuous blood cardioplegia for 45 minutes (antegrade group, n = 8 and simultaneous antegrade-retrograde group, n = 9), All pigs were weaned from cardiopulmonary bypass 45 to 60 minutes after a ortic unclamping, Indices of left ventricular function were measured a fter another 30 minutes with the conductance catheter technique and pr essure-volume loops, Results: Global left ventricular function, evalua ted by preload recruitable stroke work decreased from baseline values of 126 (102 to 150) (mean [90% confidence limits]) (antegrade) and 122 (116 to 127) erg/ml x 10(3) (simultaneous) to 75 (61 to 89) (p = 0.00 4) and 95 (79 to 112) erg/ml x 10(3) (p = 0.02), respectively, End-dia stolic pressure-volume relation increased from 0.25 (0.21 to 0.28) (an tegrade) and 0.30 (0.25 to 0.35) mm Hg/ml (simultaneous) to 0.60 (0.41 to 0.79) (p = 0.009) and 0.53 (0.35 to 0.71) mm Hg/ml (p = 0.02), res pectively, The time constant of left ventricular pressure relaxation w as unchanged, No intergroup difference was observed in preload recruit able stroke work, preload recruitable stroke work area, end-diastolic pressure volume relation, or stiffness constant, Plasma levels of trop onin T increased without any difference between groups, Myocardial wat er content was increased in the simultaneous group (81.1% [80.7% to 81 .5%]) versus the antegrade group (80.1% [79.6% to 80.7%], p = 0.01), C onclusion: Despite a small increase in myocardial,vater content induce d by simultaneous blood cardioplegia, no impairment of postcardioplegi c cardiac function was observed compared with antegrade cardioplegia.