Fontan Circulation and Aortic Stiffness: Insights into Vascular Dynamics and Haemodynamic Interplay

Area of Science:

• Cardiovascular Medicine
• Vascular Biology
• Pediatric Cardiology

Background:

• Increased aortic stiffness is linked to cardiac afterload and impaired cardiac function.
• Congenital heart diseases and extensive surgeries, such as those for univentricular heart conditions, can elevate aortic stiffness.
• The Fontan procedure is a complex surgery for univentricular hearts, and its long-term effects on aortic properties require investigation.

Purpose of the Study:

• To assess aortic stiffness in distinct aortic segments in Fontan patients.
• To determine if aortic stiffness parameters in Fontan patients correlate with Fontan-specific hemodynamics.
• To compare aortic stiffness between Fontan patients and heart-transplanted controls.

Main Methods:

• A prospective case-control study involving 20 Fontan patients and 49 heart-transplanted controls.
• Invasive cardiac catheterization to measure pulse wave velocity (PWV) in the ascending aorta and the entire aorta.
• Assessment of hemodynamic parameters including pressures, cardiac index, and systemic vascular resistance index.

Main Results:

• Fontan patients showed significantly higher ascending aorta PWV (aPWV) compared to controls (7.2 vs. 4.9 m/s).
• Central aorta PWV (cPWV) was similar between Fontan patients and controls.
• Multivariate analysis confirmed elevated aPWV in Fontan patients, independent of age and BMI. Correlations between cPWV and blood pressure were weaker in Fontan patients.

Conclusions:

• Fontan patients demonstrate increased vascular stiffness specifically in the ascending aorta.
• Overall aortic stiffness in Fontan patients is comparable to controls, suggesting segment-specific changes.
• Further research is warranted to elucidate the clinical implications of increased ascending aorta stiffness on Fontan circulation and long-term cardiovascular outcomes.