Wall Shear Stress and pulmonary regurgitation before and after TPVI for repaired tetralogy of Fallot: 4D flow MRI assessement.

Motivation: To evaluate Transcatheter Pulmonary Valve Implantation (TPVI) as an alternative to traditional open surgery for pulmonary regurgitation in repaired-Tetralogy of Fallot patients and to identify causes of regurgitation progression. Goal(s): Assess TPVI's impact on cardiac function and pulmonary regurgitation. Investigate wall shear stress (WSS) as a predictive factor. Approach: In this prospective study of 20 patients, ventricular function, pulmonary regurgitation fraction, WSS, and pulmonary artery cross-sectional area were measured before TPVI, 3 months later, and for some (9 patients), 1 year later. Results: TPVI reduced right ventricular volume and regurgitation fraction, and the preoperative early diastolic WSS was reduced, suggesting improved vascular remodeling. Impact: 4D Flow MRI can assess early diastolic WSS derived from pulmonary regurgitation in repaired-Tetralogy of Fallot before TPVI, potentially serving as a new biomarker for predicting worsening of pulmonary regurgitation and considering TPVI indications.