Peak circulatory power is a strong prognostic factor in patients with idiopathic pulmonary arterial hypertension

Abstract

Background: Studies have shown that peak circulatory power (peak CircP; peak oxygen uptake × peak systolic blood pressure) is a variable predictor of prognosis in patients with left heart failure. It remains unknown whether peak CircP also predicts outcome in patients with idiopathic pulmonary arterial hypertension (IPAH).

Methods: Patients with newly diagnosed IPAH who underwent symptom-limited cardiopulmonary exercise testing (CPET) from 1 January 2011 to 1 January 2014 in Fuwai Hospital were prospectively enrolled and followed for up to 66 months for cardiac events (mortality and lung transplantation).

Results: One hundred forty patients with IPAH (104 female, mean age: 33 ± 11 years) were studied. During follow-up (mean: 42 ± 14 months), 24 patients died and 1 patient underwent lung transplantation. In the univariate analysis, peak oxygen uptake(VO₂), oxygen uptake at anaerobic threshold, ventilation (VE)/carbon dioxide output (VCO₂) slope, end-tidal partial pressure of carbon dioxide at anaerobic threshold, peak systolic blood pressure (SBP), the change of SBP, the change of heart rate, peak work rate, peak CircP, pulmonary vascular resistance, cardiac index and World Health Organization functional class were predictive of cardiac events (all P < .05).In the multivariate analysis, Peak CircP in the fourth model had the highest significance compared with peak VO₂ and VE/VCO₂ slope in the second and third model (chi-square = 5.26, P < .02, HR: 0.99, 95% CI: 0.99 to 1.00).

Conclusions: Peak CircP, better than peak VO₂ and VE/VCO₂slope, was a strong predictor of cardiac events among exercise parameters in patients with IPAH.

Keywords: Cardiopulmonary exercise testing; ClinicalTrials.gov:NCT02061787; Idiopathic pulmonary arterial hypertension; Peak circulatory power; Prognosis.