Magnetic resonance imaging to assess the hemodynamic effects of pulmonary valve replacement in adults late after repair of tetralogy of Fallot

Background - Pulmonary regurgitation (PR) late after total correction for tetralogy of Fallot may lead to progressive right ventricular (RV) dilatation and an increased incidence of severe arrhythmias and sudden death. Timing of pulmonary valve replacement (PVR) is subject to discussion, because the effect of PVR on RV function in adults is unclear. In this study, MRI was used to assess the effect of PVR on RV function and PR. Clinical improvement was established by means of the NYHA classification. Methods and Results - Twenty-six adult patients were included. Cardiac MRI was performed at a median of 5.1±3.4 months before and 7.4±2.4 months after PVR. Mean preoperative PR was 46±10% (range, 25% to 64%). After PVR, 20 of 26 patients (77%) showed no residual PR, 5 patients showed mild residual PR, and 1 patient showed moderate PR. RV end-diastolic volume (RV-EDV) decreased from 305±87 to 210±62 mL (P<0.001), and RV end-systolic volume (RV-ESV) decreased from 181±67 to 121 ±58 mL (P<0.001). No significant change was found in RV-EF (42% versus 42%). However, RVEF corrected for regurgitations and shunting increased from 25.2±8.0% to 43.3±13.7% (P<0.001). Mean validity class improved from 2.0 to 1.3 (P<0.001). Conclusions - In adult patients with PR and RV dilatation, late after total correction of tetralogy of Fallot, MRI measurements show remarkable hemodynamic improvement of RV function after PVR and improvement of validity. We therefore advocate a less restrictive management concerning PVR in these patients.