Laboratory confirmation of clinical heart allograft preservation variability

Background. Previously, we reported survival differences from the national heart transplant registry favoring centers that used intracellular organ preservation solutions. To eliminate center selection bias, we tested some of these solutions in a biventricular working rat heart model to determine their relative efficacy. Methods. Using 103 Sprague-Dawley rat hearts perfused with modified Krebs-Henseleit buffer, both ventricles functioned with adjustable independent preload and afterload and their pressure–length loops generated load-insensitive measurements of cardiac performance. After 15 minutes of stable function, each heart sustained 180 minutes of cold (4°C) ischemia after a 5-minute perfusion by University of Missouri (UMC), Plegisol, Collins, University of Wisconsin, Custodiol, or Roe solutions. Eighty-two hearts were reperfused and the remainder were used for ATP analyses. Results. Although the extracellular solution Plegisol showed good recovery of traditional hemodynamic values, including developed pressure and cardiac output, intracellular solutions like Roe had superior preservation of load-insensitive indices such as preload recruitable stroke work: Roe (intracellular) 103% ± 13%; Custodiol (intracellular) 96% ± 9%; UW (intracellular) 69% ± 12%; Collins (intracellular) 68% ± 9%; Plegisol (extracellular) 68% ± 7%; and University of Missouri (extracellular) 56% ± 10% (p = 0.04). Furthermore, recovery with intracellular solutions tended to be gradual but more progressive after ischemia in contrast to an early plateau shown by extracellular (p < 0.001). Right ventricular recovery and ATP measurements were similar between groups. Conclusions. These data support the superiority of certain intracellular preservation solutions and provide evidence that optimal heart organ protection may be difficult to judge clinically using hemodynamic values routinely available to the heart transplant surgeon. Care should be taken to verify the performance of some solutions used in heart organ transplantation.