Pulmonary Vascular Distensibility: An Early Marker of Pulmonary Vascular Disease

Decreased pulmonary vascular distensibility was associated with right ventricular (RV) pulmonary arterial uncoupling in patients with unexplained exercise intolerance and normal resting echocardiography results, according to the results of a recent study published CHEST.

Researchers evaluated rest and exercise invasive pulmonary hemodynamics, ventilation, and gas exchange in patients with unexplained exercise intolerance and normal resting echocardiography results. A pulmonary vascular distensibility coefficient α was determined from multipoint pressure-flow plots. RV pulmonary arterial coupling was quantified from the analysis of RV pressure curves to determine ratios of end-systolic to arterial elastances. Aerobic exercise capacity was estimated by peak oxygen consumption. Correlations between α coefficient and RV pulmonary arterial coupling was compared between groups.

Ultimately, 44 patients with heart failure with preserved ejection fraction, 22 patients with exercise pulmonary hypertension, 19 patients with pulmonary arterial hypertension, and 24 individuals who served as controls participated in the study. The α coefficient decreased from 1.35%±0.58%/mm Hg in control participants and 1.1%±0.48%/mm Hg in patients with passive heart failure with preserved ejection fraction, to 0.62%±0.32%/mm Hg in those with exercise pulmonary hypertension, 0.54%±0.27%/mm Hg in patients with heart failure with preserved ejection fraction with high exercise peripheral vascular resistance, and 0.18±0.16/mm Hg in those with pulmonary arterial hypertension.

Pulmonary vascular distensibility was associated with decreased end-systolic to arterial elastances and peak oxygen consumption.

The study authors wrote, “[P]ulmonary vascular distensibility is a sensitive hemodynamic marker for early detection and progression of pulmonary vascular disease in patients with unexplained dyspnea,” the researchers concluded. “These findings suggest pulmonary vascular distensibility might be useful as an adjunct diagnostic hemodynamic marker and potential therapeutic target for patients with exertional intolerance and abnormal pulmonary vascular response to exercise.”

Reference

Singh I, Oliveira RKF, Naeije R, et al. Pulmonary vascular distensibility and early pulmonary vascular remodeling in pulmonary hypertension [published online May 20, 2019]. CHEST. doi:10.1016/j.chest.2019.04.111