Functional Capacity Assessment in Adults After Fontan Palliation: A Cardiopulmonary Exercise Test-Invasive Exercise...

Area of Science:

• Cardiology
• Pediatric Cardiology
• Cardiopulmonary Physiology

Background:

• Cardiopulmonary exercise testing (CPET) parameters have established prognostic value in adults following Fontan palliation.
• Limited data exist correlating non-invasive treadmill CPET with invasive exercise hemodynamics in this population.
• The invasive hemodynamic factors contributing to exercise limitations post-Fontan remain incompletely understood.

Purpose of the Study:

• To investigate the correlation between treadmill CPET parameters and invasive exercise hemodynamics in adults with prior Fontan palliation.
• To identify CPET predictors of abnormal invasive hemodynamic responses during exercise.

Main Methods:

• Retrospective analysis of 55 adults (≥18 years) who underwent treadmill CPET prior to invasive exercise hemodynamic testing (supine cycle protocol).
• Data collected between November 2018 and April 2023.
• Analysis focused on relationships between peak heart rate (HR), peak oxygen consumption (VO2), and invasive hemodynamic measures (pulmonary artery pressures, PAWP).

Main Results:

• Peak HR and peak VO2 were inversely related to exercise pulmonary artery (PA) pressures and PA wedge pressures (PAWP).
• VO2/HR correlated with exercise stroke volume index, but not arterio-mixed venous O2 content difference.
• A peak VO2 ≤48% predicted demonstrated optimal sensitivity (74%) and specificity (81%) for predicting elevated indexed exercise PAWP or PA pressures.

Conclusions:

• Lower peak HR and peak VO2 during CPET are associated with higher exercise PAWP and PA pressures in Fontan survivors.
• A predicted peak VO2 ≤48% serves as a valuable cutoff for identifying abnormal underlying hemodynamics.
• Clinicians should consider low peak VO2 on CPET as a potential indicator of adverse hemodynamic conditions post-Fontan palliation.