Association of Pulmonary Hypertension With Outcomes in Kidney Transplant Recipients

Abstract

Introduction: Pulmonary hypertension (PHTN) in patients with kidney failure is known to be associated with increased morbidity and mortality. Despite this, there is a relative paucity of large cohort data regarding its clinical impact following kidney transplantation (KTx). Therefore, this study sought to directly evaluate the prognostic implications of pretransplant PHTN in one of the largest kidney transplant cohorts to date.

Methods: This retrospective observational cohort analysis reviewed all consecutive kidney transplant recipients at three tertiary transplant centers in the United States between January 1, 2011 and September 30, 2021. Pretransplant PHTN was defined as right ventricular systolic pressure (RVSP) ≥ 35 mm Hg on transthoracic echocardiography (TTE). Clinical outcomes were compared between patients with and without pretransplant PHTN, including mortality and allograft failure (overall and censored by mortality).

Results: A total of 5322 KTx recipients were included; mean age 55.2 ± 13.7 years, 58.8% male. Of these patients, 1726 (32.4%) had pretransplant PHTN. PHTN was independently associated with significantly poorer outcomes: mortality (adjusted hazard ratio [aHR]: 1.24, 95% confidence interval [CI]: 1.06-1.45, P = 0.007), overall allograft failure (aHR 1.24, 95% CI: 1.09-1.42, P = 0.002), and death-censored allograft loss (aHR: 1.25, 95% CI: 1.01-1.56, P = 0.044). Risk of mortality and overall allograft failure also appeared to be incrementally higher with increasing pulmonary pressures.

Conclusion: Pretransplant PHTN classified by echocardiographic RVSP was independently and incrementally associated with an increased risk of mortality and allograft failure post-KTx. In pretransplant work up, this may allow for identification of a high-risk cohort that could benefit from further evaluation, early intervention, and closer surveillance in the posttransplant period.

Keywords: allograft survival; kidney transplant; outcomes; patient survival; pulmonary hypertension.

Graphical abstract

Figure 1

Flow diagram of study design for the evaluation of pulmonary hypertension in kidney transplant recipients.

Figure 2

Kaplan-Meier analysis of impact of pulmonary hypertension on mortality in kidney transplant recipients at 5 years posttransplant, defined as right ventricular systolic pressure (RVSP) ≥ 35 mm Hg (A), then further analysis of the impact of incrementally increasing pulmonary pressures as separated by pulmonary pressure quartiles (B).

Figure 3

Kaplan-Meier analysis of impact of pulmonary hypertension on overall graft failure in kidney transplant recipients at 5 years posttransplant, defined as right ventricular systolic pressure (RVSP) ≥ 35 mm Hg (A), then further analysis of the impact of incrementally increasing pulmonary pressures as separated by pulmonary pressure quartiles (B).

Figure 4

Kaplan-Meier analysis of death-censored allograft loss in kidney transplant recipients with and without pulmonary hypertension, defined as right ventricular systolic pressure ≥ 35 mm Hg.