Heart Transplant: UNOS Policy Cut Wait Times, Mortality, but Post-transplant Survival Increased

Changes in the U.S. United Network for Organ Sharing (UNOS) heart allocation policy in 2018 appear to have resulted in improved wait list times, as well as reductions in wait list mortality and increases in transplant rates, researchers found.

According to Arman Kilic, MD, Division of Cardiac Surgery, University of Pittsburgh Medical Center, and colleagues, a major goal of the new policy was to reduce wait list mortality. Thus, “In this respect, the policy seems to be successful,” they wrote in JAMA Cardiology.

However, at the same time, they determined that post-transplant 1-year survival decreased by almost 5% over the same time period.

Kilic and colleagues’ study accentuated earlier concerns about the unintended consequences of the UNOS heart allocation policy change, Clyde W. Yancy, MD, MSc, of the Division of Cardiology at Northwestern University Feinberg School of Medicine in Chicago and deputy editor of JAMA Cardiology, and Gregg C. Fonarow, MD, of Ahmanson-UCLA Cardiomyopathy Center in David Geffen School of Medicine at University of California, Los Angeles, and associate editor for health care quality and guidelines at JAMA Cardiology, wrote in an editor’s note.

“The intentions [of the policy change] were well considered, but the policy has been associated with an off-target 29% increased likelihood of worse outcomes,” Yancy and Fonarow pointed out. “Were this a therapeutic, considerations for early marketplace withdrawal would be well underway.”

While they support policy change and process improvement, Yancy and Fonarow wrote that those changes must be for the good and not cause excessive harm. Thus, they added, “given the broad and immediate impact of policy change and the potential for harm, we argue for a reconsideration of the current UNOS heart reallocation policy and for a higher evidence bar prior to future policy implementations.”

According to Kilic and colleagues, the change made by the Organ Procurement and Transplantation Network, which is administered by the UNOS, involved converting the existing 3-tier system to a 6-tier system in order to “provide more granular separation of wait listed patients by clinical condition and urgency of transplant.” The intended goal behind the change was to reduce wait list times and mortality and provide broader sharing of donor organs.

In this cohort study, the authors wanted to assess changes in patient characteristics, wait list outcomes, and post-transplant outcomes after the policy change.

Of the 15,631 patients undergoing transplant, 10,671 were wait listed before, and 4,960 wait listed after, the policy change. Wait list outcomes included:

• A reduction in the risk of death or clinical deterioration after the policy change (subhazard ratio [SHR], 0.60; 95% CI, 0.52-0.69).
• A significantly greater increase in the odds of undergoing transplant after the policy change (SHR, 1.38; 95% CI, 1.32-1.45).
• A significant decrease in the likelihood of wait list removal after the policy change (SHR, 0.54; 95% CI, 0.40-0.73).
• Lower rates of 90-day wait list mortality (6.3% vs 5.0%) and one-year wait list mortality (13.3% versus 11.7%) after the policy change.

A total of 6,078 patients underwent heart transplant before the policy change, and 2,801 underwent heart transplant after. After the policy change there were higher rates of postoperative new-onset dialysis (703 [11.6%] before versus 356 [14.3%] after the policy change) and stroke (171 [2.8%] before versus 98 [3.9%]), while rates of postoperative pacemaker implantation (144 [2.4%] before versus 58 [2.3%] after the policy change) as well as drug-treated short-term rejection (735 [12.1%] before versus 285 [11.5%] after the policy change) did not significantly change.

Length of hospital stay was also similar between the two groups of transplant patients (21.2 days before the policy change compared to 21.4 days after).

Kilic and colleagues observed that 1-year survival was 4.6% lower after the policy change (87.5%; 95% CI, 85.0%-89.5%) compared with before the policy change (92.1%; 95% CI, 91.3%-92.7%), and that this finding persisted after risk adjustment (HR, 1.29; 95% CI, 1.07-1.55). They explained that with the shift that occurred in patient characteristics after the policy change, “these findings are not unexpected.”

For example, they noted that bridging with extracorporeal membrane oxygenation (ECMO) increased more than 5-fold after the policy change, and that recipients bridged with ECMO have reduced early and late survival, as well as an increased risk of primary graft dysfunction. In addition, the authors pointed out that both congenital heart disease and pretransplant mechanical ventilation were present in higher proportions after the policy change, and both are among the strongest factors associated with 1-year mortality after adult heart transplant.

“One could argue that the clear improvements in wait list outcomes justify the 4.6% decrease in 1-year survival in a higher-risk patient subset,” wrote Kilic and colleagues. “Others may argue that the substantial increase in bridging with ECMO and other temporary mechanical circulatory support modalities has resulted in worse post-transplant outcomes and adjustments to allocation should therefore be made.”

“The transplant community will ultimately need to weigh the advantages and disadvantages with the new allocation system as demonstrated in this analysis,” they concluded.

1. Changes in U.S. heart allocation policy have improved wait list times and reduced wait list mortality.

2. However, in the year after the policy changes were implemented, post-transplant survival decreased by almost 5%, which is a cause for concern, as noted in an editorial commentary calling for the policy changes to be reconsidered.

Michael Bassett, Contributing Writer, BreakingMED™

Cat ID: 631

Topic ID: 630,631,631,633,3,5,914,192,150,925,159,312,492,635