Wave intensity analysis with exercise identifies impairments in pulmonary hypertension

Area of Science:

• Cardiovascular Physiology
• Pulmonary Circulation
• Biomedical Engineering

Background:

• Pulmonary hypertension (PH) involves elevated pulmonary arterial pressures and vascular remodeling, impacting right ventricle (RV) function.
• Understanding the dynamic interplay between the RV and pulmonary vasculature is crucial for diagnosing and managing PH.
• Current methods may not fully capture the complex mechanical interactions in different PH phenotypes.

Purpose of the Study:

• To investigate the utility of wave intensity analysis (WIA) in characterizing RV and pulmonary vascular mechanics across various PH phenotypes.
• To assess how WIA metrics change during exercise in individuals with and without PH.
• To explore the relationship between WIA, hemodynamics, RV function, and oxygen consumption.

Main Methods:

• Prospective study involving 22 participants with PH and 3 controls.
• Quantification of forward and backward compression/decompression waves using WIA at rest and during incremental exercise (25-75 W).
• Analysis of relationships between WIA metrics, hemodynamics, RV function, and oxygen consumption using linear mixed-effects modeling.

Main Results:

• Distinct WIA patterns were observed, reflecting vessel-specific pulmonary vascular and RV pathobiology in different PH phenotypes.
• Precapillary PH showed higher forward compression waves, correlating with RV contractility.
• Isolated postcapillary PH demonstrated a decrease in the backward to forward compression wave ratio during exercise, indicating RV reserve capacity.

Conclusions:

• WIA during exercise provides insights into ventricle- and vessel-specific impairments in PH.
• WIA can help differentiate PH phenotypes and assess RV reserve capacity.
• This analysis is a promising tool for advancing the understanding of cardiopulmonary pathophysiology in PH.