Analysis of cavopulmonary and cardiac flow characteristics in fontan Patients: Comparison with healthy volunteers.

BACKGROUND

Characterizing the flow of the Fontan circuit, and correlating flow characteristics with the development of complications, is an important clinical challenge. Past work has analyzed the flow characteristics of Fontan circulation on a component-by-component basis. 4D flow MRI with radial projections allows for large volumetric coverage, and therefore can be used to analyze the flow through many codependent cardiovascular components in a single imaging session.

PURPOSE

To describe flow characteristics across the entire Fontan circuit and to compare these with the flow characteristics in healthy volunteers.

STUDY TYPE

Prospective.

SUBJECTS

Eleven single ventricle patients with a Fontan connection and 15 healthy controls.

SEQUENCE

Phase contrast with vastly undersampled isotropic projection reconstruction (PC-VIPR) at a field strength of 3 T.

ASSESSMENT

Cavopulmonary and ventricular flow distributions, blood flow kinetic energy, vorticities, efficiency indices, and other flow parameters were analyzed using Ensight and MatLab.

STATISTICAL TESTS

The results were compared across Fontan subjects, between respiratory phases, and between Fontan subjects and healthy volunteers using a Student's t-test for unequal sample sizes and linear regression.

RESULTS

Cava-specific pulmonary flow distributions of Fontan patients varied significantly between respiratory phases (P < 0.05). Ventricular kinetic energy (KE) was significantly higher in Fontan patients than it was in healthy controls, leading to a lower cardiac efficiency metric in the Fontan group. A significant diastolic KE time-shift was also observed in the Fontan patient group. Peak diastolic KE was significantly higher in the single ventricle of patients with right ventricle morphology than it was in left ventricle morphology patients.

DATA CONCLUSION

Radial 4D flow MRI can be used for comprehensive analysis of single ventricle Fontan flow characteristics.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019.