Myocardial release of hypoxanthine and lactate during percutaneous transluminal coronary angioplasty.

The response of myocardial lactate and hypoxanthine metabolism during percutaneous transluminal coronary angioplasty was studied in a series of 15 patients undergoing this procedure. A minimum of 4 balloon inflations was performed per patient with an average duration per occlusion of 49 +/- 11 seconds (mean +/- standard deviation) for a total occlusion time of 192 +/- 40 seconds. Thermodilution coronary venous blood flow measured in the great cardiac vein decreased from control values of 72 +/- 4 ml/min (mean +/- standard error of the mean) to 47 +/- 10 ml/min with the fourth coronary occlusion (p less than 0.005). Arteriovenous lactate and hypoxanthine showed peak differences during the reactive hyperemia after the first 2 occlusions which did not increase after subsequent occlusions. Within minutes after the procedure, lactate and hypoxanthine efflux was no longer seen, demonstrating the reversibility of the metabolic disturbances after repeated ischemia. The results of this study indicate that there is no permanent alteration in lactate or hypoxanthine metabolism after percutaneous transluminal coronary angioplasty with 4 coronary occlusions of 40 to 60 seconds' duration, with a total occlusion time of 192 +/- 40 seconds.