Survival benefit from transplantation greatest in highest-risk patients
The risk for wait-list mortality varies among heart transplant candidates, and new study data found that survival benefit is increased for candidates with higher risk for wait-list mortality.
However, researchers found no measurable survival benefit for many candidates at the lower end of the risk spectrum.
Tajinder P. Singh, MD, MSc, of Boston Children’s Hospital, and colleagues aimed to assess survival benefit from transplantation, as defined by reduction in risk for 30-day mortality and 1-year mortality upon receiving a heart transplant.
Using the Organ Procurement and Transplantation Network database, the researchers identified patients aged at least 18 years listed for their first heart transplant in the United States from 2007 to 2010 (n=10,159; median age, 55 years). Patients who received multi-organ transplantation were not included in the study.
Risk prediction model
Singh and colleagues developed a model to predict risk for wait-list mortality within 90 days and stratified listed patients into deciles based on that risk. Survival benefit was quantified as the reduction in risks for 90-day and 1-year mortality on receiving a heart transplant close to listing. Primary endpoints included death without transplantation and death after transplantation.
Of the patients listed for heart transplant, 59% received a heart, 10.4% died without receiving a heart (695 died while on wait list, 359 died after removal) and 27% were still waiting for a transplant 1 year after listing. Of those who died without receiving a transplant, 31% died within 30 days of listing, 57% within 90 days and 77% within 180 days.
Of the 5,720 patients who received a transplant and for whom 1-year follow-up was available, 10.1% died within 1 year after transplant.
In the risk-prediction model, the risk for 90-day mortality without receiving a heart transplant increased from 1.6% in the lowest-risk group to 19% in the highest-risk group.
Singh and colleagues identified several risk factors for post-transplant 90-day mortality, including older age, congenital heart disease, restrictive or ischemic cardiomyopathy, ventilator support, mechanical support and renal dysfunction at transplant.
Survival benefit from a heart transplant increased progressively the higher the risk for death without transplant, the researchers found. However, survival benefit from heart transplant at 90 days was negative or neutral in the six lowest-risk groups. For most of those patients, the risk for post-transplant mortality was higher than or similar to the risk for wait-list mortality, they found. Survival benefit increased from 1.7% in the seventh risk group to 8.5% in the 10th risk group.
One-year mortality without transplant increased from 5.2% in the lowest risk group to 26.7% in the highest risk group, the researchers reported.
“Considering survival benefit from [heart transplantation] or improving the stratification of listed patients in prioritizing heart allocation may improve overall outcomes in patients listed for [heart transplantation],” Singh and colleagues wrote. “Importantly, these findings support the need for a re-examination and revision of the current heart allocation in the United States and suggest one possible approach.”
Promising first step
This study “is a promising first step toward a novel organ allocation system based on distinct risk-prediction models that reflect our current medical and surgical treatment options, regional factors and regulatory limitations,” Donna M. Mancini, MD, of Columbia University Medical Center, wrote in a related editorial.
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Disclosure: The researchers and Mancini report no relevant financial disclosures.