Pre-transplant PH Does Not Affect 5-year Survival After Kidney Transplant
Among people selected for kidney transplant, the presence of pre-transplant pulmonary hypertension (PH) is associated with an increased risk of transplanted kidney dysfunction at five years, according to a single-center study in the U.S. looking at 350 patients.
However, this risk did not affect the five-year survival of patients with PH, highlighting that carefully selected patients with this condition can experience similar long-term benefits from kidney transplant to those without PH.
The study, “Effect of pulmonary hypertension on 5-year outcome of kidney transplantation,” was published in the journal Pulmonary Circulation.
Kidney transplant “is the recommended management option for patients with progressive or end-stage kidney disease,” the researchers wrote. However, only the best candidates — those with the best chances of survival based on simultaneous health conditions — are chosen for such a transplant.
Pulmonary hypertension, or high blood pressure in the blood vessels that supply the lungs, is a common complication of both chronic and end-stage kidney disease, estimated to affect 23% of cases.
PH previously was associated with a two-times higher risk of death in people with end-stage kidney disease on dialysis, and also is known to increase the risk of health complications and death during the perioperative period, which is the period right before, during, and right after surgery.
While “this risk profile may suggest that patients with PH are poor kidney transplantation candidates,” the researchers wrote, some reports suggest that kidney transplant may ease PH, likely by correcting chronic excess fluid in the body.
As such, it is important to understand if the benefits of kidney transplant extend to this high-risk group of people with PH and outweigh the known higher perioperative risk, the team added.
To address this, scientists at Emory University School of Medicine, in Atlanta, retrospectively analyzed the five-year outcomes of 350 people (210 men and 140 women) who underwent a single-organ kidney transplant at Emory Transplant Center in the years of 2010 and 2011.
The presence of PH was determined through pre-transplant echocardiography, which has been shown to be in good agreement with results of right heart catheterization, the gold standard method for PH assessment.
The team analyzed the potential link between pre-transplant PH and patients’ risk of death, graft dysfunction, or graft failure at five years after the kidney transplant. Graft refers to any transplanted tissue; in this case, it was the kidney.
Patients’ median age at the time of surgery was 51 and most (85%) were on dialysis for a median of nearly three years. Nearly all (96%) had a history of high blood pressure. The graft organ came from deceased donors in 67% of cases. Follow-up data were available for 99% of patients.
Results showed that 117 patients (33%) had evidence of PH and that this group of patients did not differ from those without PH in terms of age, simultaneous conditions, or pre-transplant kidney replacement therapy.
At five years, 10% of patients had died and an additional 10% had experienced graft failure.
When analyzing the risk of any of the three outcomes and adjusting for potential influencing factors, the team found that the presence of PH was associated with a 43% increased risk of death, graft dysfunction, or graft failure. A similar higher risk was linked to male sex.
But when the researchers analyzed the frequency of each outcome separately, only graft dysfunction was significantly more common among patients with PH (57% vs. to 33% in those without PH).
Notably, there were no significant changes in terms of time from kidney transplant to death between patients with and without PH.
These findings highlighted that “PH is common in kidney transplant recipients and is associated with worsened 5-year transplant outcomes mainly driven by the increased incidence of graft dysfunction,” the researchers wrote.
“Importantly, survival in our [group of patients] at 5 years was excellent (90% overall) and did not differ among those with and without PH,” they added.
“While institutional and regional differences in outcome can be expected, this report suggests that carefully selected patients with pulmonary hypertension receive similar long-term benefits from kidney transplantation,” the researchers wrote.
“The known benefits of improved quality and quantity of life afforded by kidney transplantation likely outweigh the marginal increased risk of graft dysfunction at 5 years” observed in patients with PH, the team wrote, adding that kidney transplant therefore should be considered in this patient group, too.
In addition, the observed higher risk of graft dysfunction with PH “may inform the risk/benefit assessment” in end-stage kidney disease patients “or modify the intensity of posttransplantation monitoring,” they added.