Greater survival benefit in simultaneous heart-kidney transplant vs. single organ

ByRegina Schaffer

Fact checked byRegina Schaffer

Heart-kidney transplantation relative to heart transplantation alone was associated with superior survival regardless of dialysis status and for patients with moderate kidney disease, according to a national transplant registry analysis.

In an analysis of more than 13,000 patients who underwent simultaneous heart-kidney transplant or heart transplant alone, researchers also found that patients who received both organs were also at higher risk for kidney allograft loss compared with patients who received isolated, contralateral kidney allografts.

Graphical depiction of data presented in article — Heart-kidney transplantation relative to heart transplantation alone was associated with superior survival regardless of dialysis status and for patients with moderate kidney disease.
Data were derived from Itagaki S, et al. *J Am Coll Cardiol*. 2023;doi:10.1016/j.jacc.2022.11.053.

“Simultaneous heart-kidney transplantation does help patients who have end-stage HF and concurrent kidney dysfunction to some extent, but this also comes at the cost of significantly increased risk for losing the implanted kidney compared to if the kidney was transplanted in isolation,” Shinobu Itagaki, MD, MSc, assistant professor of cardiovascular surgery at Mount Sinai Medical Center, told Healio. “This finding might bring complex dilemmas and clinical implications, as we as clinicians focus on the patients in front of us. But, it is important that we are always cognizant of the concept of the societal utility and benefit under the limited supply of valuable organs.”

Assessing nationwide registry data

Shinobu Itagaki

Using the United Network for Organ Sharing registry, Itagaki and colleagues compared long-term mortality among 1,124 adults with kidney dysfunction who underwent heart-kidney transplantation vs. 12,415 adults who underwent isolated heart transplantation in the U.S. between 2005 and 2018. Among heart-kidney recipients, researchers compared contralateral kidney recipients for allograft loss.

The findings were published in the Journal of the American College of Cardiology.

Researchers found that, at 5 years, long-term mortality was lower among heart-kidney recipients than among heart-alone recipients when recipients were on dialysis, with mortality rates of 26.7% and 38.6%, respectively (HR = 0.72; 95% CI, 0.58-0.89).

Five-year mortality rates similarly favored heart-kidney recipients vs. heart-alone recipients among those with a glomerular filtration rate (GFR) of less than 30 mL/min/1.73 m² (HR = 0.62; 95% CI, 0.46-0.82) and those with a GFR of 30 mL/min/1.73 m² to 45 mL/min/1.73 m² (HR = 0.68; 95% CI, 0.48-0.97), but not among patients with a GFR of 45 mL/min/1.73 m² to 60 mL/min/1.73 m².

In interaction analyses, the mortality benefit of heart-kidney transplantation continued up to a GFR of 40 mL/min/1.73 m². Incidence of kidney allograft loss was higher among heart-kidney recipients vs. contralateral kidney recipients, with 1-year rates of 14.7% and 4.5%, respectively (HR = 1.7; 95% CI, 1.4-2.1).

In half of the cases, heart-kidney transplantation was performed “preemptively” in recipients not on dialysis, whereas most contralateral kidney allograft recipients were dialysis-dependent, according to researchers.

The researchers wrote that more work is needed to improve the allocation system for heart and kidney transplantation to avoid premature or futile kidney transplantation in candidates for heart transplantation.

“We need more studies to predict in which cases the native kidney may recover just by isolated heart transplantation and also to predict in which cases the transplanted kidney has high risk for losing its function,” Itagaki told Healio. “These studies would give us some guidance to avoid too premature or too futile simultaneous kidney transplantation use so that we can maximize the societal utility and benefit balance.”

Benefit ‘at significant cost’

In a related editorial, Andrew Civitello, MD, FACC, and Ajith Nair, MD, FACC, FAHA, both from the Heart Transplant Program and Baylor St. Luke’s Medical Center and Baylor College of Medicine/Texas Heart Institute, noted that the study is the first to provide insight into the competing outcomes of survival in simultaneous heart-kidney recipients with renal allograft loss in heart-kidney vs. isolated kidney transplant recipients.

“On an individual patient level, the significant survival benefit afforded by simultaneous heart-kidney transplantation to patients with end-stage HF and varying degrees of kidney disease seen in prior studies was reaffirmed,” Civitello and Nair wrote. “However, on a population level, this benefit came at a significant cost, with almost twice the risk of renal allograft loss in simultaneous heart-kidney recipients compared with contralateral-lateral kidney transplant recipients. The findings of this study provide further clarity as to who may benefit from simultaneous heart-kidney transplantation and reinforces the need for a safety net allowing for appropriate organ allocation to maximize survival benefits for both heart and renal transplant candidates.”