Wave intensity analysis with exercise identifies impairments in pulmonary hypertension.

Abstract

Wave intensity analysis provides a novel approach to understanding the dynamic interactions between the right ventricle and pulmonary vasculature, particularly in pulmonary hypertension, a condition characterized by elevated pulmonary arterial pressures and vascular remodeling. This prospective study used wave intensity analysis to evaluate right ventricular and pulmonary vascular mechanics in 22 participants with pulmonary hypertension (including precapillary, isolated postcapillary, and combined pre/postcapillary pulmonary hypertension), and three without pulmonary hypertension. Forward and backward compression and decompression waves were quantified at rest and during incremental exercise (25, 50, and 75 W). Relationships between metrics of wave intensity analysis, hemodynamics, right ventricular function, and oxygen consumption were analyzed using linear mixed-effects modeling. Wave intensity patterns highlighting vessel-specific pulmonary vascular and right ventricular pathobiology were observed in different phenotypes. Precapillary pulmonary hypertension exhibited highest forward compression waves, which correlated with right ventricular contractility (P < 0.01). Backward compression waves correlated strongly with characteristic impedance (P = 0.002) in combined pre/postcapillary pulmonary hypertension and inversely with pulmonary arterial compliance (P = 0.003) in precapillary pulmonary hypertension. The ratio of backward to forward compression (systolic) waves decreased in isolated postcapillary pulmonary hypertension during exercise (P < 0.001), suggesting right ventricular reserve capacity that improves vascular-ventricular coupling. Wave intensity metrics demonstrated strong correlations with oxygen consumption in participants without pulmonary hypertension, indicating sensitivity to exercise-induced changes in cardiopulmonary status. Wave intensity analysis with exercise suggests vessel-specific pulmonary vascular and right ventricular characteristics unique to pulmonary hypertension phenotypes. These findings highlight wave intensity analysis as a promising tool for advancing understanding of cardiopulmonary pathobiology in pulmonary hypertension.NEW & NOTEWORTHY Wave intensity analysis (WIA) during exercise reveals distinct ventricle-/vessel-specific impairments across PH phenotypes. Cpc-PH exhibited highest forward and backward compression waves, reflecting elevated RV energy expenditure and pulmonary vascular stiffness, respectively. Precapillary PH demonstrated higher forward and backward decompression waves, suggesting differences in RV and pulmonary vascular mechanics. The compression reflection index decreased in Ipc-PH with exercise, indicating RV reserve capacity. These findings highlight WIA's potential for phenotyping PH and advancing cardiopulmonary pathophysiology assessment.