Patients with Fontan circulation have abnormal aortic wave propagation patterns: A wave intensity analysis study.

Area of Science:

• Cardiovascular Physiology
• Hemodynamics
• Medical Imaging

Background:

• Elevated systemic afterload in Fontan circulation can impair single ventricular function.
• Wave intensity analysis (WIA) is a tool to evaluate vascular wave dynamics.
• Unfavorable wave propagation may contribute to reduced functional capacity in single ventricle patients.

Purpose of the Study:

• To investigate if abnormal wave propagation contributes to excessive afterload.
• To assess the impact of wave propagation on single ventricle function and exercise capacity.

Main Methods:

• Phase-contrast MRI-based WIA was performed on patients with hypoplastic left heart syndrome (HLHS) (n=25), single left ventricle (SLV) (n=24), and controls (n=10).
• Analysis focused on the ascending aorta, measuring forward compression waves (FCW), backward compression waves (BCW), and forward decompression waves (FDW).
• Wave components were indexed to each other, and correlations with peak oxygen consumption (VO2) were examined.

Main Results:

• FCW was significantly lower in HLHS and SLV groups compared to controls.
• The BCW/FCW ratio, indicating vascular stiffness, was higher in HLHS and SLV patients.
• Reduced FCW and systolic MRI indices correlated with peak VO2, suggesting a link between wave propagation and exercise intolerance.

Conclusions:

• Patients with HLHS and SLV demonstrate unfavorable aortic WIA patterns, characterized by increased BCW/FCW.
• This indicates increased systemic afterload due to retrograde compression waves.
• Abnormal systolic wave propagation may contribute to exercise intolerance in Fontan patients.