Myocardial metabolism during aortic valve replacement. I. Hypothermic crystalloid cardioplegia with mannitol.

Myocardial energy metabolism during hypothermic potassium cardioplegia with addition of mannitol was studied in five patients undergoing aortic valve replacement. Myocardial biopsies were taken from the left ventricle 10 min after the aortic cross-clamping and immediately before declamping and were analyzed for ATP, lactate and glycogen. The ATP concentration fell (13.2 +/- 3.6-11.0 +/- 4.3 mmol X kg-1 dry muscle), the lactate concentration rose (61.5 +/- 17.6-86.6 +/- 13.3) and glycogen decreased (181 +/- 54-143 +/- 3 mmol X kg-1 d.m.). Use of mannitol in a crystalloid cardioplegia solution does not prevent pronounced anaerobic metabolism in the myocardium during aortic valve replacement.