In a rapidly changing world, can we truly predict the impact of liver graft quality 15 years from now?

This is the authors' abstract. We don't add key points for this paper.

See Article on Page 1040 Two recent studies published in Liver Transplantation note that the absolute number of organ donors has steadily increased in recent years. However, there has been a decrease in the availability of donor organs for deceased donor liver transplantation.1 Reasons include an aging population, an increasing prevalence of obesity and diabetes, and an increase in the number of liver grafts that are discarded, which primarily has involved organs harvested by donation after cardiac death (DCD). Regulatory oversight and the consequences of poor outcomes have led to risk aversion in a large number of liver transplant programs. In turn, this has contributed to the gap between the number of patients waiting for liver transplantation and donor organ availability, which is reflected in the fact that more than 20% of patients listed for liver transplant will drop off the waiting list.3 In this issue of Liver Transplantation, Orman et al.2 emphasize the impact of these imminent donor trends. They suggest that if practices remain constant over the next 15 years, utilization of liver donors will fall from 78% to 44% by the year 2030, resulting in 2230 fewer liver transplants and that the transplant community will be forced to accept inferior grafts leading to potentially worse outcomes. These predictions are based on previous Scientific Registry of Transplant Recipients and population trends, and they are assumed to continue unchanged over the next 15 years. They predict that liver donors greater than age 50 years (39.2% in 2010) will increase to 43.7% by 2030. They also suggest that donors with a body mass index of greater than 30 kg/m2 will increase from 31.2% currently to 58.2% and that the prevalence of diabetes in donors will increase from a present level of 13.8% to 45.7%. They further estimated that overall liver utilization from donors will fall from 77.9% in 2010 to 43.6% in 2030. Are these estimates realistic and do recent population studies support these projections? A recent report by Ogden et al.4 indicates that overall there have been no significant changes in obesity prevalence in youth or adults between 2003 and 2012. Although the obesity prevalence remains high, it has not continued to increase. Likewise, Geiss et al.5 found that although there was a doubling of the incidence and prevalence of diabetes between 1990 and 2008, the prevalence of diabetes plateaued between 2008 and 2012, with an overall slight decrease in prevalence in 2012. This suggests that the prevalence of diabetes and obesity in donors for 2030 might not be as great as feared. The authors also note that in their baseline model, the use of DCDs will continue to increase. However, over the last 5 years, there has not been an increase in DCD utilization, and in my opinion, DCDs will only increase if there are technological advances such as ex vivo reperfusion that will prevent the cholangiopathy commonly associated with DCD donors.6 Solving this problem has important implications and is clearly an area where research dollars are needed so that DCD livers can be used safely. Other factors that will influence the future of liver transplant will be the changing population of liver transplant recipients. Almost certainly, within 15 years, we will see a marked decrease in transplant candidates with hepatitis C virus (HCV)‐related cirrhosis and hepatocellular cancer recipients now that curative therapy for HCV is available. In addition, organs from older donors implicated in the increased severity of recurrence of HCV can now be used in HCV‐infected recipients given the efficacy of oral antiviral therapy. Furthermore, the highest prevalence of HCV is in the Baby Boomer population born between 1946 and 1964, who in 15 years will be too old for transplant in many cases. Will fatty liver disease increase as projected and become the leading indication for liver transplant? An analogy may be made with smoking for which national campaigns have markedly reduced smoking in the United States. Similar programs such as “Let's Move!” initiated by First Lady Michelle Obama, may eventually improve dietary habits decreasing the prevalence of obesity and diabetes. In addition, it is conceivable that in the next 15 years we will have medical and surgical therapy (bariatric surgery) which will markedly diminish the complications related to obesity, diabetes, and fatty liver disease. In addition, new approaches and developing technology applied to extended criteria donors or marginal donors, including DCD, will have a major impact on increasing acceptable liver donors. Already reports have claimed the ability to resuscitate marginal liver allografts for transplantation with ex vivo perfusion technology.6 Finally, decisions about organ quality vary widely between transplant centers and often lead to unintentionally missed predictions; they are susceptible to external forces such as policy changes, regulatory scrutiny, competition between centers, and financial issues, which often lead to refusal of organs and possible missed opportunities for a successful transplant. Volk and Berg8 have introduced a new model of decision support for organ offers in liver transplantation by using statistical modeling to determine gain or loss of life by accepting a given organ versus waiting for the next organ for a given patient.9 The hope is that this concept will be able to augment clinical judgment and may help centers that are risk averse into accepting marginal organs that have a high likelihood of success and reduce the present discard rate. In summary, although it is important to project potential current trends regarding liver donors, I believe the estimates made by these authors may be overstated on the basis of recently published population studies. Thus, at this time in a rapidly changing world with advancing technology, it is impossible to predict 15 years ahead the impact of liver donors on future results of liver transplantation. I believe that in the future, we will be using donor livers that we have never used before and will be achieving similar excellent results as we have today.