THE LIMITS OF CARDIAC PRESERVATION WITH UNIVERSITY-OF-WISCONSIN SOLUTION

Previous studies from this institution have suggested that University of Wisconsin solution is preferred for prolonged cardiac storage and preserves high-energy phosphates better than other storage fluids. University of Wisconsin solution contains adenosine (5 mmol/L), which may maintain the concentration of myocardial adenine nucleotides. Cultures of human adult myocytes were grown from left ventricular biopsy specimens obtained from patients undergoing coronary bypass procedures. Cells (seven to nine dishes per group) were rinsed of culture medium and stored at 0-degrees-C in University of Wisconsin solution. Cells were analyzed for adenine nucleotide content after 1, 6, 12, and 24 hours of storage by high-performance liquid chromatography (units = nmol/mu-g DNA) and compared with control samples (0 hour). Adenosine concentration increased from 0.03 +/- 0.02 (mean +/- standard deviation) to 1.77 +/- 1.03 by 1 hour (p < 0.0001, analysis of variance) and remained increased thereafter. Adenosine was largely degraded to inosine (0 hours, 0.03 +/- 0.03; 6 hours, 0.88 +/- 0.56; p < 0.001) and hypoxanthine (0 hours, 0.01 +/- 0.01; 6 hours, 0.15 +/- 0.09; p = 0.004). Measured levels of xanthine and uric acid were extremely low at all time intervals. Adenosine triphosphate levels were maintained at 1 hour (0 hours, 0. 64 +/- 0.38; 1 hour, 0. 67 +/- 0.45) but declined thereafter (6 hours, 0.21 +/- 0.21; 12 hours, 0.11 +/- 0.09; 24 hours, 0.04 +/-0.03; p < 0.0001). Levels of adenosine diphosphate (p = 0.007) and adenosine monophosphate (p < 0.05) decreased to approximately 25% of original values by 24 hours. University of Wisconsin solution does not prevent the degradation of adenine nucleotides during hypothermic storage and may not permit adequate cardiac preservation beyond the present limits.