Evaluation of pulmonary endothelial function in Fontan patients

Area of Science:

• Cardiology
• Pediatric Cardiology
• Pulmonary Hypertension

Background:

• Fontan circulation leads to pulmonary vascular resistance (PVR) due to loss of pulsatile blood flow.
• Pulmonary endothelial dysfunction is a key factor in developing increased PVR in Fontan patients.

Purpose of the Study:

• To evaluate pulmonary endothelial dysfunction in children and adolescents with Fontan hemodynamics.
• To assess vasodilator response to acetylcholine in Fontan patients.

Main Methods:

• Twenty-one Fontan patients underwent cardiac catheterization with intra-arterial Doppler and pressure measurements.
• Pulmonary flow reserve (PFR) was quantified by acetylcholine-induced changes in peak velocity.
• Local PVR was assessed using the ratio of local pressure to blood flow velocity.

Main Results:

• Acetylcholine infusion significantly increased average peak velocity, indicating a mean PFR of 1.28 ± 0.37.
• Local PVR significantly decreased after acetylcholine administration (P = .01).
• A strong correlation was observed between baseline local PVR and PFR, and between PFR and the percent decrease in local PVR.

Conclusions:

• Pulmonary flow reserve and local PVR assessment can aid in evaluating pulmonary vascular remodeling in Fontan patients.
• These measures may serve as an adjunct to standard catheterization protocols, especially when global PVR is difficult to assess.
• Further research is needed to determine if impaired local pulmonary endothelial function is linked to Fontan failure.