Background: Renal impairment is frequent in pulmonary arterial hypertension (PAH), yet renal function is not currently accounted for in the European Society of Cardiology (ESC)/European Respiratory Society (ERS) risk stratification tools. We investigated whether renal function provides independent prognostic information in PAH after adjustment for ESC/ERS risk score. Methods: We conducted a retrospective analysis of the French Pulmonary Hypertension (PH) Network registry. Estimated glomerular filtration rate (eGFR) was calculated using the 2021 CKD-EPI equation. Renal dysfunction prevalence (eGFR <60 mL·min ⁻¹ ·1.73 m ⁻² ) was assessed in patients with PAH (n=3383). Time-to-event analyses for transplant-free survival were performed using Cox models adjusted for age, sex and ESC/ERS risk scores at baseline and at 3–12 months of follow-up. Results: Renal dysfunction (eGFR <60 mL·min ⁻¹ ·1.73 m ⁻² ) was present in 28% of patients with PAH. Baseline eGFR <45 mL·min ⁻¹ ·1.73 m ⁻² was independently associated with reduced transplant-free survival in multivariable analysis. At 3–12 months of follow-up, eGFR <60 mL·min ⁻¹ ·1.73 m ⁻² predicted adverse outcomes in multivariable models (HR 1.25; 95% CI 1.04–1.50; p=0.018). Among patients with preserved baseline renal function, a relative decline in eGFR of ≥10% was independently associated with a higher risk of death or lung transplantation. Conclusions: Baseline renal impairment and subsequent deterioration in renal function are independently associated with poorer transplant-free survival in PAH, beyond ESC/ERS risk stratification. These findings support consideration of renal function in prognostic assessment of patients with PAH.

Background/Objectives: Real-world data on pulmonary arterial hypertension (PAH) in Romania are scarce. This study evaluated the clinical characteristics, long-term survival patterns and the prognostic utility of baseline variables in a Romanian PAH cohort. Methods: We retrospectively analyzed adult patients treated for PAH at a single expert center between 2007 and 2026. The primary outcome was a composite of all-cause mortality or lung transplantation. Survival was assessed using Kaplan–Meier and univariable Cox proportional-hazard regression models. Univariable and multivariable linear regressions were used to identify drivers of baseline estimated glomerular filtration rate (eGFR). Results: The primary analysis cohort included 75 patients (mean age 53 ± 15 years, 71% female). Overall transplant-free survival was unexpectedly high at 97.2%, 80.8%, and 66.7% at 1, 3, and 5 years, respectively. The European Society of Cardiology (ESC)/European Respiratory Society (ERS) 3-strata risk score did not stratify survival (log-rank p = 0.9). Significant predictors of adverse outcomes in univariable analysis included six-minute walking distance (6MWD), PAH etiology and baseline coronary artery disease. In univariable analysis, lower baseline eGFR was associated with age, hypertension and diabetes mellitus, but not with pulmonary hemodynamics or transplant-free survival. Conclusions: In this regional PAH cohort, survival rates were high, likely reflecting survivor bias stemming from delayed access to care. Adverse outcomes were associated with PAH etiology and 6MWD, but the limited number of events precluded multivariable analysis.

Pulmonary hypertension (PH) is a severe and highly prevalent complication of chronic kidney disease (CKD). Conversely, patients with pulmonary arterial hypertension (PAH) frequently develop renal dysfunction. These cardio–renal interactions predict poorer outcomes, yet their mechanisms are not entirely understood. This narrative review explores the pathophysiological interactions between the pulmonary circulation and the kidney and the impact on patient care. PH in CKD is driven by a combination of left heart disease, volume overload and endothelial dysfunction. Molecular mechanisms include an imbalance of endogenous vasoactive agents favouring increased vasoconstriction, as well as vascular remodelling induced by mediators of mineral bone metabolism (parathyroid hormone, fibroblast growth factor 23, α-Klotho). In haemodialysis patients, arteriovenous fistulas (AVFs) contribute to PH via a high cardiac output state. Management of CKD-PH relies on strict volume control, treating underlying comorbidities and modulating high AVF flow. Targeted PAH therapies are generally contraindicated in CKD-PH. Kidney transplantation can reverse PH in a significant proportion of patients. Pulmonary vascular remodelling in PAH can induce renal dysfunction through reduced renal perfusion and increased venous congestion (the right heart cardio–renal syndrome). Impaired kidney function in PAH predicts increased mortality and warrants more aggressive vasodilator therapy. The association of PH and CKD is frequent and confers a poor prognosis. Accurate diagnosis and effective management require a multidisciplinary approach involving pulmonologists, cardiologists and nephrologists.