Cerebrovascular blood flow in patients with tetralogy of fallot: prediction for early surgical intervention

OBJECTIVES: Children with tetralogy of Fallot (TOF) require initial intervention at varying times reflecting a spectrum of obstruction to pulmonary blood flow. In utero, fetal patients with right sided obstructive lesions demonstrate increased middle cerebral artery (MCA) pulsatility index (PI). We sought to determine whether MCA flow patterns are associated with the degree of pulmonary obstruction and the consequential need for early surgical intervention (ESI). METHODS: We performed a multi-center retrospective study evaluating patients with a prenatal diagnosis of TOF. All echocardiographic fetal studies performed from 16 weeks' gestational age through delivery were reviewed between 2001 and 2015 with subsequent postnatal medical chart review. RESULTS: 82 patients met inclusion criteria. Patients who ultimately required ESI (n=30) demonstrated an increased MCA PI z-score (-0.68 vs -1.32, p=0.02) compared to those who did not (n=52). An elevated MCA PI in patients with TOF was associated with ESI after 24 weeks' gestational age (-0.36 vs -1.22, p=0.02). CONCLUSIONS: Fetal patients with TOF demonstrate altered MCA flow that correlates with need for ESI. This effect is blunted earlier in gestation which may reflect cerebral autoregulation. MCA PI may be a beneficial tool in helping determine perinatal management and counseling for patients with TOF.