The law of supply and demand translates into life and death for thousands of people in the United States who are desperate for a new heart. Because of a severe shortage of organs to meet the growing need, some 350 people died last year while waiting for a heart transplant. Aware of the inequities and disparities in the current system of adult heart allocation, the Organ Procurement and Transplantation Network (OPTN) and United Network for Organ Sharing (UNOS) have proposed significant changes that are being debated by the transplant community. Will the new rules provide a fresh lifeline for the sickest of the sick, or simply add another layer of complexity and cost to a system that struggles to achieve fairness and efficiency?
Cracks in the nation’s program for organ sharing have grown deeper and more disturbing as the number of candidates for a heart transplant has soared in recent years. Take, for example, a patient with ventricular arrhythmia in New York City who is given months to live without a new heart. Suddenly, a suitable organ becomes available from a trauma victim just across the Hudson River, in Newark, N.J. The distance between the two might as well be the Atlantic Ocean since the heart is offered instead to a less urgent, relatively stable candidate who happens to reside closer to the heart donor. Chalk that decision up to current OPTN/UNOS rules governing the geographic sharing of organs—rules that favor less needy candidates in the local donation service area (DSA) vs. patients on the brink who might live 25 miles away but, sadly, outside the relatively small DSA.
Other imperfections in the system have surfaced with the increased use of mechanical circulatory support devices (MCSD). According to OPTN/UNOS, nearly 36 percent of heart transplant candidates were registered while on these devices in 2014, up from 16 percent in 2007, resulting in “more complications…often requiring urgent transplantation.” In the view of many, however, the heart allocation system has failed to keep pace with technology through better stratification of candidates based on the type of MCSD support they have and the risks associated with specific device complications. Not surprisingly, status 1A (the most urgent) candidates supported by mechanical ventilation or extracorporeal mechanical oxygenation (ECMO) have the highest waiting list mortality rates, up to 36 percent.
These deficiencies and others have not been lost on OPTN and UNOS, which jointly manage the unified organ transplant network for the U.S. Department of Health and Human Services. For the first time since 2006, they have proposed sweeping changes to the adult heart allocation system designed to improve its equity and access by patients across the country. “The practice of medicine has changed in the last decade, and we now have a better idea how to risk-stratify patients and help the sickest people get transplanted quicker by offering them organs from a broader geography,” says Joseph Rogers, MD, interim chief of the Division of Cardiology at Duke University School of Medicine, and chair of the OPTN/UNOS Thoracic Organ Transplantation Committee, which drafted the proposed heart allocation guidelines. “Our modeling suggests that we can reduce for patients the risk of either dying while on the transplant waiting list or being removed from it because they became too sick to be successfully transplanted.”
A new stratification formula
To improve timely access to transplantation by the sickest on the waiting list, OPTN/UNOS has developed a new status hierarchy along with more liberal sharing of organs between geographic zones. Specifically, the guidelines would replace existing statuses 1A, 1B and 2 with a numbered scheme, 1 through 6, based on medical urgency. The notion behind increasing the number of statuses is to allow for better stratification of heart transplant candidates as well as quicker movement up or down the prioritization scale as the patient’s condition worsens or improves. To facilitate broader organ sharing, the proposed rules recommend that statuses 1 and 2 be given first consideration when a suitable donor heart becomes available. Thus, the most urgent candidates within the donor hospital’s DSA would have top priority, as the current system mandates, but the next in line would no longer be a less needy 1B candidate within the DSA. Instead, the heart would be offered to a status 1 or 2 patient within surrounding Zone A, then Zone B (which extend