Novel echocardiographic parameters in pulmonary hypertension assessment and the relationship between echocardiography and 6-minute walking test

Abstract

Pulmonary artery stiffness (PAS) has been shown to be related to pulmonary artery pressure in patients with pulmonary artery hypertension (PAH). The aim of this study was to determine the correlation between functional capacity and echocardiographic indices of PAS in patients with PAH. This cross-sectional study was performed on patients with PAH who were confirmed by right heart catheterization and referred to Imam Reza PAH clinic for routine follow-up between November 2019 and January 2020. All patients underwent echocardiography and the maximum Doppler frequency shift, pulmonary acceleration time, peak velocity of the pulmonary flow, and velocity time integral, as well as PAS, were measured. All patients performed a 6-minute walk test. Fifty patients with a mean age of 41.90 ± 14.73 years old participated in this study. The majority of the patients were female (74%). The most common cause of PAH was idiopathic (74%). There was a significant correlation between PAS and pulmonary artery systolic pressure (r = 0.302, P = .041), second pulmonary valve pulse Doppler velocity (V2) (r = −0.461, P = .003), time from onset of pulmonary flow ejection to V2/first pulmonary valve pulse Doppler velocity (r = −0.311, P = .037) and Z3 ratio (r = −0.346, P = .023). There was no significant correlation between PAS and 6-minute walk test, pulmonary vascular resistance, and tricuspid annular plane systolic excursion (P > .05). There was a significant correlation between V2 and pulmonary vascular resistance (r = 0.359, P = .049). PAS and first pulmonary valve pulse Doppler velocity are simple, noninvasive, available tools for the evaluation of pulmonary vascular beds and diagnosis of presymptomatic clinical status in patients with PAH.