Pulmonary blood flow patterns in patients with Fontan circulation

Area of Science:

• Cardiovascular Physiology
• Medical Imaging

Background:

• Fontan surgery creates a single-ventricle physiology, altering pulmonary blood flow dynamics.
• The impact of the cardiac cycle on pulmonary blood flow patterns in Fontan patients remains largely uncharacterized.

Purpose of the Study:

• To investigate and characterize pulmonary blood flow patterns in patients with Fontan circulation.
• To compare these patterns with those of healthy individuals.

Main Methods:

• Phase-velocity cine magnetic resonance imaging (MRI) was used to assess pulmonary artery blood flow in 17 Fontan patients and 12 healthy volunteers.
• Flow patterns were normalized and averaged over 3 minutes to mitigate respiratory influences.

Main Results:

• Fontan patients exhibited highly variable blood flow peaks and troughs.
• Averaged flow patterns in Fontan patients showed only a subtle late diastolic flow acceleration.
• Healthy controls displayed distinct systolic peaks and late diastolic troughs in both vena cava and pulmonary artery flows.

Conclusions:

• Patients with Fontan circulation do not demonstrate typical cardiac-originated pulmonary blood flow patterns.
• The observed slight late diastolic flow acceleration in Fontan patients suggests diastolic inflow restriction.