The addition of glutathione (YM737) to a crystalloid cardioplegic solution enhances myocardial protection.

The effectiveness of a glutathione preparation, YM737, as a free radical scavenger when added to hypothermic (4 degrees C) crystalloid cardioplegic solution was evaluated in this study. Rabbit hearts were preserved for 3 h in cardioplegic arrest by infusing 20 ml crystalloid cardioplegic solution initially, with additional 10-ml boluses administered every 30 min, while maintaining a myocardial temperature of 10 degrees C. They were then reperfused with Krebs-Henseleit bicarbonate buffer at 37 degrees C in a perfusion circuit for 60 min. The hearts were divided into two groups of six: One in which crystalloid cardioplegic solution was perfused (group 1); and one in which crystalloid cardioplegic solution containing YM737 1 mg/ml was perfused (group 2). The postischemic developed pressure (mmHg) in group 2 was significantly greater than that in group 1 after 60 min of reperfusion, being 44.8 +/- 8.4 versus 87.8 +/- 5.2 in groups 1 and 2, respectively (P < 0.01). Moreover, group 2 exhibited significantly lower postischemic left ventricular compliance after 60 min than group 1 (P < 0.01) and a significantly higher postischemic peak LV dp/dt (mmHg/sec) after 60 min of reperfusion, being 925 +/- 213 versus 1,550 +/- 111 in groups 1 and 2, respectively (P < 0.05). Based on the comparisons of postischemic hemodynamics it was concluded that the addition of glutathione to crystalloid cardioplegic solution does in fact enhance myocardial protection.