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Background. Various solutions are used for donor heart preservation. We examined the outcomes in our heart transplant population where histidine-tryptophanketoglutarate (HTK) solution has been used for heart preservation since 2004.Methods. This was a retrospective review of the United Network for Organ Sharing (UNOS) database (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016) comparing our heart transplant outcomes with other national centers. Propensity matching in a 1:3 ratio was performed to adjust for preoperative recipient variables.Results. After propensity matching comparing UNOS outcomes (n [ 1080) with our institutional data (n [ 360), there was no difference in matched preoperative variables. Donor hearts were similar for donor age, sex, donor-to-recipient size ratio, LVEF, and ischemic time. Our HTK cohort had a larger proportion with donor cardiac arrest (26.3% vs 6.1%, P < .001) and longer cardiac arrest duration (22.1 ± 16.0 vs 17.2 ± 14.0 minutes, P [ .052). Our primary graft dysfunction (PGD) rate requiring mechanical support was 4.2% (n [ 1). Postoperative mechanical support use for PGD included extracorporeal membrane oxygenation in 9 (60.0%), intraaortic balloon pump in 4 (26.7%), right ventricular assist device in 3 (20%), and biventricular assist device in 3 (20%). Overall survival at our institution was similar to the national average (P [ .649). Survival at 1, 5, and 10 years with HTK was 92.2%, 81.3%, and 70.8%, and for the UNOS population was 91.6%, 80.3%, and 62.0%, respectively.Conclusions. Use of HTK solution for donor hearts was associated with a low rate of severe PGD. Overall survival was not significantly different from other institutions using a variety of preservation solutions in the UNOS database during the same period. HTK solution is efficacious for preservation of donor hearts.

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In recent years, there has been increased interest in fuel cells as a promising energy storage technology. The environmental impacts due to the extensive fossil fuel consumption is becoming increasingly important as greenhouse gas (GHG) levels in the atmosphere continue to rise rapidly. Furthermore, fuel cell efficiencies are not limited by the Carnot limit, a major thermodynamic limit for power plants and internal combustion engines. Therefore, hydrogen fuel cells could provide a long-term solution to the automotive industry, in its search for alternate propulsion systems. Two most important methods for hydrogen delivery to fuel cells used for vehicle propulsion were evaluated in this study, which are fuel processing and hydrogen storage. Moreover, the average fuel cost and the greenhouse gas emission for hydrogen fuel cell (H2 FCV) and gasoline fuel cell (GFCV) vehicles are compared to that of a regular gasoline vehicle based on the Argonne National Lab’s GREET model. The results show that the average fuel cost per 100 miles for a H2 FCV can be up to 57% lower than that of regular gasoline vehicles. Moreover, the obtained results confirm that the well to wheel greenhouse gas emission of both H2 FCV and GFCV is significantly less than that of regular gasoline vehicles. Furthermore, the investment return period for hydrogen storage techniques are compared to fuel processing methods. A qualitative safety and infrastructure dependency comparison of hydrogen storage and fuel processing methods is also presented.