Midgestation Fetal Pulmonary Annulus Size Is Predictive of Outcome in Tetralogy of F allot

Background Surgical management of tetralogy of F allot ( TOF ) is increasingly moving toward valve‐sparing approaches rather than transannular patch ( TAP ). We evaluate whether fetal pulmonary valve ( PV ) size is predictive of postnatal course and surgical approach in TOF . Methods In this retrospective study, fetal and postnatal demographic, clinical, and echocardiographic data on 66 patients diagnosed prenatally with TOF were collected. We compared those with midgestation PV   z ‐score > −3.5 to those with z ‐score ≤−3.5. We analyzed fetal and postnatal PV size and growth and outcomes between groups Results Gestational age at first fetal echo was 23 weeks (range 18–28). PV diameter and z ‐score on midgestation echo were 3.5 mm (1.3–6.0) and −2.8 (−0.5 to −6.0) respectively. Patients with PV   z ‐score ≤ −3.5 on first fetal echo had smaller PV diameter (4.5 vs. 5.0 mm, P = .047) and PV   z ‐score (−3.8 vs. −2.8, P < .001) in late gestation and at time of surgery (6.0 mm vs. 7.0 mm, P = .01; z ‐score = −2.9 vs. −1.7, P = .007). Similarly, those with smaller fetal PV   z ‐score had smaller main and branch pulmonary arteries at time of surgery. PV growth rate over gestation was similar between groups, while after‐birth PV growth rate was lower in those with smaller PV (0 mm/month vs. 0.6 mm/month, P = .002). Those with smaller pulmonary valve were more likely to be cyanotic ( P = .05), to undergo surgery at <1 month ( P < .01), and to have a TAP repair ( P = .01). Among patients undergoing valve‐sparing repair, those with smaller PV underwent more reinterventions for residual valvar PS ( P < .01). Conclusion Midgestation fetal PV size is predictive of postnatal PV and PA size in TOF . Midgestation PV size has implications for timing and type of surgical management as well as for need for reintervention in valve‐sparing repair patients and is therefore important to consider in prenatal counseling for TOF fetuses.