Tetralogy of Fallot: prediction of outcome in the mid-second trimester of pregnancy

Objective: To evaluate the usefulness of fetal echocardiography in the mid-second trimester in predicting postnatal outcome of tetralogy of Fallot (ToF), focusing on the need for early intervention (EI) and surgery type: pulmonary valve-sparing surgery (PVSS) versus placement of transannular patch (TAP).

Methods: Assessment of cardiac morphological and functional parameters in 23 live-born fetuses with isolated ToF was performed at 19 to 22 and 34 to 38 weeks. Comparisons were made between outcome groups (EI vs non-EI and PVSS vs TAP). EI was considered as requirement either of palliative procedure or corrective surgery before three months.

Results: Overall survival was 96%. EI was required in 32% of cases and TAP in 50%. At 19 to 22 weeks, a pulmonary valve peak systolic velocity (PVPSV) ≥87.5 cm/s predicted EI with 100% sensitivity and 93.3% specificity (p < 0.01). At 34 to 38 weeks, the size of the pulmonary valve, pulmonary valve/aortic valve and main pulmonary artery/ascending aorta were significantly different, but the PVPSV again yielded the best performance: all cases undergoing EI and/or TAP were selected using cut-off of ≥144.5 cm/s.

Conclusion: The postnatal outcome of fetuses with ToF may be established using PVPSV from the mid-second trimester. This may be useful in providing the most appropriate perinatal management and accurate parental counselling.