Sub-normothermic preservation of donor hearts for transplantation using a novel solution, Somah: A comparative pre-clinical study

Background Hearts preserved ex vivo at extreme hypothermia (4°C) undergo time-dependent irreversible injury. Our studies using a novel solution, Somah, suggest that hearts are viably preserved at 21°C. In this study we evaluate the relative efficacy of Somah for preservation of hearts at 21°C when compared with the clinically used Celsior and University of Wisconsin (UWS) solutions. Methods Porcine hearts arrested by cardioplegia at 21°C using Somah, Celsior or UWS solution were stored in the respective solutions at 21°C ( n = 5) for 5 hours and then reperfused ex vivo for functional assessment. We assessed development of edema, cardiac tissue high-energy phosphate (HEP; ATP + creatine phosphate) levels and release of cardiac enzymes. Alterations in left ventricular wall thicknesses and functional parameters were examined by 2-dimensional (2D) echocardiography. Changes in myocardial oxygen consumption (MVO 2 ) and lactate utilization were assessed at reperfusion. Results Heart weights were unaltered during 5-hour storage in all groups. After storage, HEP levels were 28.33 ± 5.51, 10.20 ± 2.78 and 5.92 ± 1.46 nmol/liter per milligram protein ( p p Conclusions Increased synthesis of HEP, rapid metabolic switch and optimal function together provide evidence that hearts procured for transplantation are preserved in a superior viable condition at 21°C with Somah, but not with other commonly used clinical preservation solutions.