Longitudinal Pulmonary Arterial Pressure Trajectories Inform Clinical Outcome in Kidney Transplantation Patients.

BACKGROUND

Pulmonary hypertension (PH) is a high-risk finding in end-stage kidney disease (ESKD) and is independently associated with increased mortality.

RESEARCH QUESTION

What is the relationship between pulmonary artery pressure (PAP) trajectories from pre-kidney transplantation (KT) to post-KT, as well as the role of PH post-KT?

STUDY DESIGN AND METHODS

We retrospectively analyzed patients in the Veterans Affairs Healthcare System with PAP values both pre-KT and post-KT using echocardiography. The primary exposure was all-cause mortality, stratified according to PH status (systolic PAP > 35 mm Hg) into four groups: No-PH (no PH pre-KT or post-KT), New-PH (no PH pre-KT but PH post-KT), Resolved-PH (PH pre-KT but no PH post-KT), and Persistent-PH (PH pre-KT and post-KT). Findings were validated in the sex-balanced Vanderbilt University Medical System using echocardiography and right heart catheterization.

RESULTS

From 631 patients (60 ± 6 years; 96% male) in the primary cohort, 364 (58%) there were 231 (36.6%), 184 (29.2%), 133 (21.1%), and 83 (13.1%) patients in the Persistent-PH, Never-PH, Resolved-PH, and New-PH groups, respectively. New-PH and Persistent-PH were associated with a 51% (hazard ratio [HR], 1.51; 95% CI, 1.06-2.15; P = .023) and 37% (HR, 1.37; 95% CI, 1.03-1.82; P = .029) increase in age- and sex-adjusted mortality risk compared with No-PH. Of all groups, Resolved PH was associated with the most favorable survival rate (adjusted HR, 0.73; 95% CI, 0.51-1.05; P = .087, compared with No-PH). Longitudinal mortality risk increased continuously with ≥ 1 mm Hg PAP increase from pre-KT to post-KT. Overall, a 21% increase in mortality risk per 10 mm Hg increment increase in echocardiographic systolic PAP (sPAP) was observed from pre-KT to post-KT, adjusted for age, sex, and baseline sPAP (HR, 1.21; 95% CI, 1.11-1.31; P < .001); a 10 mm Hg sPAP decrease was associated with a 17% decrease in adjusted mortality risk (HR, 0.83; 95% CI, 0.76-0.90; P < .001). Results were reproducible in the validation cohort.

INTERPRETATION

In patients with ESKD referred for KT as well as hemodynamic assessment, outcome is strongly associated with PAP trajectory. These data suggest that PAP may be a novel biomarker for risk stratifying KT candidacy, supporting prospective ESKD studies investigating the role of PH in clinical decision-making.