Exercise feature and predictor of prognosis in patients with pulmonary artery stenosis-associated pulmonary hypertension.

Aims: The prognosis is poor for patients with pulmonary artery stenosis-associated pulmonary hypertension (PAS-PH). Identifying predictors of prognosis in PAS-PH is crucial to preventing premature death, which has rarely been investigated. We aimed to explore the cardiopulmonary exercise testing (CPET) parameters to predict the prognosis of these patients.

Methods: We prospectively included all patients with PAS-PH who underwent CPET between September 2014 and June 2021 in Fuwai Hospital (ClinicalTrials.gov ID: NCT02061787). The primary outcome was clinical worsening, including death, rehospitalization for heart failure, or deterioration of PH.

Results: Seventy-two patients were included in this study. A median of 2-year follow-up revealed that 18 (25%) patients experienced clinical worsening. The 1-year, 3-year, and 5-year event-free survival rates were 92.5%, 81.7%, and 62.7%, respectively. Patients with clinical worsening demonstrated significantly worse baseline haemodynamics and poorer exercise capacity than their counterparts. Multivariable Cox regression identified that peak O pulse could independently predict clinical worsening [hazard ratio: 0.344, 95% confidence interval (CI) 0.188-0.631, P < 0.001], outperforming other parameters. Peak O pulse correlated with PH severity. Incorporating peak O pulse into the simplified 2015 European Society of Cardiology/European Respiratory Society risk stratification improved the accuracy for predicting clinical worsening (pre vs. post area under the curve: 0.727 vs. 0.846, P < 0.001; net reclassification index: 0.852, 95% CI 0.372-1.332, P < 0.001; integrated discrimination index 0.133, 95% CI 0.031-0.235, P = 0.011).

Conclusions: The prognosis is poor for PAS-PH, and exercise intolerance and ventilation inefficiency are commonly observed. Peak O pulse independently predicted the prognosis of these patients. A low peak O pulse identified patients at high risk of clinical deterioration and served for risk stratification of PAS-PH.