1356585 - Hemodynamic Analysis of Pulmonary Arteries in Postoperative Adult Tetralogy of Fallot by 4D-flow MRI

Background: Using 4D-flow MRI, we evaluated hemodynamics in the pulmonary artery of repaired tetralogy of Fallot (TOF) in adulthood.

Methods: In 30 adults who underwent cardiovascular MRI, we measured energy loss (EL) and helicity of the main pulmonary artery (MPA). For EL, the maximum value (peak EL) in one heartbeat and the total value were obtained, and the total value was standardized by dividing by body surface area (EL/BSA) and cardiac index (EL/BSA/CI). Helicity was defined as a vector quantity, with clockwise rotation being positive and counterclockwise rotation being negative, and the total value was calculated.

Results: The mean age was 29.6 years, right ventricular outflow tract reconstruction was 15 cases with pulmonary valve preservation (n-TAP) and 15 cases with transannular patch (TAP), and the average postoperative period was 24.3 years. Total EL values were significantly higher during systole, but peak EL was observed during diastole in 12 patients (40%). The combined mean value of helicity was positive, with clockwise predominance in 19 cases (63%). In comparison between surgical procedures, the TAP group had a higher EL value than the n-TAP group, but there was no significant difference. Nine patients (60%) in the N-TAP group and eight patients (53%) in the TAP group showed clockwise dominant helicity, but there was no significant difference between the two groups. Whole cardiac cycle and systolic EL/BSA and MPA average through-plane velocity (r=0.49, 0.54) and area (r=-0.52, -0.56). A strong correlation was found between peak EL and clockwise helicity (r=0.74) and counterclockwise helicity (r=-0.77). In addition, a correlation was observed between diastolic EL/BSA and diastolic clockwise helicity (r=0.55) and diastolic counterclockwise helicity (r=-0.53). A correlation was observed with the pulmonary regurgitant fraction (r=0.49).

Conclusion: In this study, there was no significant difference in EL and helicity among the surgical procedures, but helicity in the MPA was dominant clockwise in repaired TOF. It was suggested that EL was involved in helicity throughout the entire cardiac cycle, and that peak EL had a particularly large effect. In the future, we would like to accumulate more cases and deepen our consideration of surgical techniques with less EL.