IMPORTANCE OF INITIAL CORONARY-ARTERY PLOW AFTER HEART PROCUREMENT TOASSESS HEART VIABILITY BEFORE TRANSPLANTATION

Background The objective of this study was to evaluate different tests of heart viability in a pig model of warm ischemia. Methods and Resul ts Pig hearts (n=30) were submitted to 0 (= group I), 10 (group II), 2 0 (group III), 30 (group IV), and 60 (group V) minutes of in situ warm ischemia (animal exsanguination). Hearts were removed, then flushed w ith cardioplegic solution for 3 minutes at a fixed pressure of 60 cm H 2O, and edema formation, initial coronary flow, and ionic composition (Na+, K+, and Ca++) of coronary sinus effluent were evaluated. Hearts were then stored for 2 hours in a cold (4 degrees C) preservation solu tion. Myocardial biopsies (and evaluation of energetic index) were per formed, then the hearts were reperfused for 30 minutes with whole bloo d with an in vitro functional testing system. No edema occurred during cardioplegic hush in the hearts in groups I through IV, but a 37+/-11 % weight increase (P<.001) occurred in hearts in group V. There was a progressive decrease in initial coronary flow with the increase in the duration of warm ischemia (70+/-14 mL/min per 100 g of tissue in grou p I and 52+/-9, 41+/-16, 25+/-11, and 23+/-5 mL/min per 100 g, respect ively, in groups II through V (P<.01 to P<.001 versus group I). Initia l coronary flow was positively correlated with the energetic index (r= .84, P<.001), and the left ventricle developed pressure at reperfusion (r=.90, P<.001). Finally, there were significant differences between hearts in the control group and those in group V for calcium and sodiu m release (lower in the control group; P<.001 and P<.01, respectively) and for potassium removal (lower in group V, P<.05). Conclusions Thes e data suggest that early measurement of coronary flow after removal o f the heart may help to assess heart viability before transplantation. This approach may provide a comprehensive clinical evaluation to incr ease the number of hearts available for transplantation among those th at are rejected in the absence of accurate criteria of viability.