Patients with newly diagnosed pulmonary hypertension (PH) and few physical limitations as defined by the World Health Organization Functional Class (WHO FC) I are at high risk of experiencing reductions in exercise capacity, according to a study published in Frontiers in Medicine.1

The ASPIRE (Assessing the Spectrum of Pulmonary Hypertension Identified at a Referral Center) registry was used to obtain data from consecutive treatment-naïve patients with newly diagnosed PH (N=895). Patients had group 1 to 5 PH with a pulmonary artery pressure of ≥25 mm Hg at right heart catheterization and a baseline incremental shuttle walk within 3 months of cardiac catheterization. The incremental shuttle walk and lung function tests were used to assess exercise capacity.

Participants with WHO CF I (n=9) demonstrated a significant reduction in exercise capacity following the shuttle walk test (incremental shuttle walk distance percent predicted [ISWD%pred] 65±20%; Z score −1.77±1.05). In addition, participants with WHO CF I demonstrated modest PH and a median pulmonary artery pressure of 31 mm Hg (interquartile range, 20 mm Hg) and pulmonary vascular resistance of 2.1 Wood Units (interquartile range, 8.2 Wood Units). Individuals with WHO FC II (n=162) had a lower ISWD%pred of 42±28% and and lower diffusion capacity of the lungs for carbon monoxide %pred of 72±24% compared with patients with WHO FC I (65±20% and 99±40%, respectively).

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The retrospective nature of the study, the enrollment of patients from a single center, and the variability in WHO FCs represented the primary study limitations.

The investigators suggested that “strategies to diagnose patients earlier when they have less symptomatic limitation is likely to identify patients with less severe pulmonary haemodynamic disease.”

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Billings CG, Lewis R, Armstrong IJ, et al. Incremental shuttle walking test distance is reduced in patients with pulmonary hypertension in World Health Organisation Functional Class I. Front Med (Lausanne). 2018;5:172.