Retrograde Flow to Aortic Root Predicts Inferior Cardiopulmonary Performance and Restrictive Lung Physiology in...

Area of Science:

• Pediatric Cardiology
• Congenital Heart Disease
• Fontan Circulation Physiology

Background:

• Cardiac output in Fontan circulation is influenced by systemic venous pressure, pulmonary vascular resistance, and ventricular function.
• Myocardial function relies on adequate coronary perfusion.
• The study investigates the impact of retrograde aortic root flow in mitral/aortic atresia subgroup of hypoplastic left heart syndrome (HLHS) on cardiopulmonary performance.

Purpose of the Study:

• To assess the effect of retrograde flow to the aortic root in HLHS patients on cardiopulmonary performance.
• To compare cardiopulmonary function and physical activity levels among different HLHS subgroups and those with left ventricular morphology.

Main Methods:

• Studied 26 stable Fontan patients (mean age 14.4 years) with right (n=17) and left (n=9) systemic ventricle morphology.
• Subdivided right ventricular patients with HLHS into antegrade (HLHS-A) and retrograde (HLHS-R) aortic flow groups based on postnatal flow patterns.
• Assessed physical activity, cardiopulmonary exercise capacity (peak oxygen uptake), body composition, and muscle fitness, correlating data with aortic and pulmonary artery size.

Main Results:

• Patients with HLHS-R reported less vigorous physical activity and had significantly lower peak oxygen uptake (VO2peak) compared to patients with left ventricular morphology.
• No significant difference in VO2peak was observed between HLHS-R and HLHS-A groups.
• HLHS-R patients exhibited the most severe lung restrictions, indicated by significantly reduced forced vital capacity and forced expiratory volume in 1 second z-scores.

Conclusions:

• Young Fontan patients with left ventricular morphology demonstrated superior cardiopulmonary performance compared to those with HLHS.
• Patients with HLHS-R were least active, had the lowest VO2peak, and most restrictive lung function.
• Identifying single ventricle patients at high risk for inactivity postnatally is essential for encouraging active and healthy lifestyles.