Differences in Organ Donation and Transplantation in States Within the United States and in European Countries: Is There a Benefit to Opting Out?

BACKGROUND: Organ donation in the United States currently requires explicit consent by an "opt-in" approach. Some European countries have reported an increase in donation rates with an "opt-out" strategy. We hypothesized that regional differences in decision making affect organ donation rates in different countries and suggest no single approach will reliably increase organ donation rates. METHODS: Donation and transplantation rates in European countries and states within the United States with populations of >10 million and a minimum organ donation rate of 10 donors per million were compared. 2016 International Registry in Organ Donation and Transplantation data and the 2016 Scientific Registry of Transplant Recipients annual report were used for European countries and US states, respectively. Comparisons by region and donation model were made. RESULTS: Deceased organ donor rates and transplants did not differ between opt-in and opt-out models. Living donation was increased in all opt-in entities. When comparing European countries, there was a trend toward higher organ donation rates in opt-out countries than in opt-in countries. Donation and transplantation rates of US states were higher than both European opt-in and opt-out countries. CONCLUSION: There were no differences in deceased donor organ donation when considering the donation consent model. These data do not support that an opt-out approach will increase the number of transplants in the United States.

Myocardial Substrate Oxidation and Tricarboxylic Acid Cycle Intermediates During Hypothermic Machine Perfusion.

BACKGROUND: The optimal substrate for hypothermic machine perfusion preservation of donor hearts is unknown. Fatty acids, acetate, and ketones are preferred substrates of the heart during normothermic perfusion, but cannot replete the tricarboxylic acid (TCA) cycle directly. Propionate, an anaplerotic substrate, can replenish TCA cycle intermediates and may affect cardiac metabolism. The purpose of this study was to determine myocardial substrate preferences during hypothermic machine perfusion and to assess if an anaplerotic substrate was required to maintain the TCA cycle intermediate pool in perfused hearts. METHODS: Groups of rat hearts were perfused with carbon-13 (13C)-labeled substrates (acetate, ß-hydroxybutyrate, octanoate, with and without propionate) at low and high concentrations. TCA cycle intermediate concentrations, substrate selection, and TCA cycle flux were determined by gas chromatography/mass spectroscopy and 13C magnetic resonance spectroscopy. RESULTS: Acetate and octanoate were preferentially oxidized, whereas ß-hydroxybutyrate was a minor substrate. TCA cycle intermediate concentrations except fumarate were higher in substrate-containing perfusion groups compared with either the no-substrate perfusion group or the no-ischemia control group. CONCLUSIONS: The presence of an exogenous, oxidizable substrate is required to support metabolism in the cold perfused heart. An anaplerotic substrate is not essential to maintain the TCA cycle intermediate pool and support oxidative metabolism under these conditions.

Right ventricular outflow tract obstruction: a quest for ideal management.

Management of right ventricular outflow tract obstruction has undergone much change over the last century. Techniques described in the literature include anatomical repairs and the use of various patches, conduits, and innovative grafts. However, many of these approaches require reoperations or catheter-based interventions, leading to increased morbidity, mortality, and cost. The search for the ideal long-lasting conduit continues and there are new techniques on the horizon, using genetic engineering and nanotechnology. This review discusses the evolution of various techniques for repair of right ventricular outflow tract obstruction, past and current conduits, as well as ongoing research.