Optimized cardiac graft preservation: a comparative experimental study using P-31 magnetic resonance spectroscopy and biochemical analyses

Abstract

Background The University of Wisconsin (UW), St. Thomas (ST) and Broussais (B) solutions were compared to the CRMBM solution, that we developed for long term heart preservation. Methods Isolated isovolumic rat hearts were arrested with each cardioplegic solution ( n = 5) to 8 hearts in each group), submitted to 12 hours of cold storage (4° C) in the same solution and then reperfused for 60 minutes at 37° C. Function was measured during control and reflow. High energy phosphates and intracellular pH were monitored by P-31 magnetic resonance spectroscopy. Analyses were performed by biochemical assays and HPLC in coronary effluents (CK, Pi, lactate, purines) and in freeze-clamped hearts (amino acids, nucleotides, CK, LDH) at the end of reperfusion. Results Functional recovery was significantly improved with the new cardioplegic solution (50 ± 12% recovery for the rate pressure product at the end of reflow vs 8 ± 3% with UW, 0% with B and with ST). This result was correlated with the best metabolic and cellular protection as assessed in particular by higher PCr levels during reflow (30 ± 3% vs 10 ± 3% with UW, 8 ± 4% with B, and 7 ± 1% with ST) as well as reduced creatine kinase leakage during reflow (110 ± 15 IU/60 minute vs 270 ± 57 IU/60 minute with UW, 323 ± 36 IU/60 minute with Broussais solution and 237 ± 18 IU/60 minute with ST). Conclusion This new solution is more effective in prolonged myocardial protection than the three most widely used solutions.