Evaluation of an oxygen delivering mobile perfusion device for organ transport

Few changes have been made to the clinical practice of donor heart preservation over the last 20 years. Using this protocol, viable storage of ex-vivo hearts is limited to no longer than 4 to 6 hours. In the present study, an oxygen delivering mobile perfusion device (ODMPD) was tested to determine if it could extend the ex-vivo heart viability using the porcine model. The first set of experiments was conducted to get baseline data. Three cadaver hearts were collected and stored for varying lengths of time to simulate different storage times using the conventional simple immersion method before being placed in the ODMPD for a minimum of 18 hours while monitoring pH, dissolved oxygen levels, and solution temperature. The second set of experiments was designed to test the ODMPD under real clinical conditions using a porcine model. A series of 13 experiments was conducted using the porcine model to simulate the conditions that the ODMPD would be expected to perform under in a human surgical setting. These experiments required the heart to be in the ODMPD from 8 to 24 hours, and in 2 cases transported in an airplane or in an automobile to simulate how they would be transported for clinical use. After all of the experiments, tissue samples were removed from the myometrium of the left ventricles and either fixed for electron microscopy or snap frozen for biochemical analysis. The biochemical analysis included testing for ATP, GSH, free iron, TBARs, and lipid radicals. After all of the tests were performed, the samples were separated by functional outcome of the transplantation and analyzed by group to determine correlations between specific biochemical levels and functional outcomes. As functionality decreased there was a positive relationship between increase in free iron (r = 9961), lipid radicals (r^2 =9995), and GSH (r^2 =8842). As functionality decreases, ATP levels decrease (r^2=.7961). These observations were supported by microscopic observations. Although this is preliminary data, it suggests that the ODMPD can both extend the viable life of the organ and could potentially facilitate the harvest of organs that were once thought to be marginally damaged by slowing the degradation processes that would render the organ useless.