Fetal umbilical-portal-systemic venous shunt: In-utero classification and clinical significance

Objectives To review our experience with fetal umbilical-portal-systemic venous shunts (UPSVS), to devise an in-utero classification system, and to analyze their clinical and prognostic characteristics. Methods This was a retrospective review of cases of UPSVS examined at an academic tertiary referral center over the 14-year period from 2001 to 2014 inclusive. The anatomical origin and drainage of the fetal umbilical, portal, ductus venosus and hepatic venous systems, and the integrity of the intrahepatic portal venous system (IHPVS), were assessed using two- and three-dimensional color Doppler sonography. Fetomaternal clinical characteristics and long-term outcome were investigated by means of medical files, imaging documentation and telephone interviews with the mothers. Results Forty-four cases with UPSVS were reviewed. Prenatal classification was based on the anatomical origin of the shunt (umbilical, portal or ductal), with cases classified into four types: Type I, umbilical-systemic shunt (n = 9 (20.4%)); Type II, ductus venosus-systemic shunt (n = 19 (43.2%)); and Type III, portal-systemic shunt, divided into two subtypes: Type IIIa, intrahepatic portal-systemic shunt (n = 12 (27.2%)) and Type IIIb, extrahepatic portal-systemic shunt (n = 4 (9.1%)). Each type presented particular clinical and prognostic characteristics. The most important favorable prognostic factors were absence of associated major malformation and presence of the IHPVS. Thus, Type IIIa (intrahepatic portal-systemic shunt) had the best outcome. Conclusions Fetal UPSVS are anomalies with a broad spectrum of manifestations and prognoses. Accurate mapping of the IHPVS is paramount for optimizing prenatal counseling and postnatal care.