Aberrant venous flow measurement may predict the clinical behavior of a fetal extralobar pulmonary sequestration

Objective: Fetal extralobar pulmonary sequestration (EPS) is sometimes complicated by a massive pleural effusion, leading to tension hydrothorax and fetal hydrops. The goal of this study was to examine sonographic signs of venous obstruction in fetal EPS with or without pleural effusion. Methods: Records of fetal ultrasound from 6 patients with EPS were reviewed with special attention to aberrant arterial and venous flow. The results were correlated with their clinical outcomes. Results: Four of the 6 cases (cases 1-4) were complicated by massive pleural effusion and required fetal thoracentesis; thoracoamniotic shunt placement was required in 3 of these 4 patients (cases 1-3). The other 2 patients (cases 5 and 6) were not associated with pleural effusion despite the comparable size of the mass and did not require any treatment, either prenatally or postnatally. In cases 1-3, aberrant venous flow was difficult to detect and, even when detected, the arterial-to-venous flow velocity ratio was >6. This is in contrast to the uncomplicated cases 5 and 6 in whom aberrant venous flow was easily detected with an arterial-to-venous flow velocity ratio of 2-3. Arterial-to-venous flow velocity ratios of 3-6 were observed in case 4. This case was complicated by pleural effusion but not by fetal hydrops. Conclusions: These data support the hypothesis that venous obstruction is related to the production of pleural effusion in fetal EPS. Ample flow in the aberrant vein may indicate benign clinical behavior, while difficulty in detecting aberrant venous flow may be correlated with the development of massive pleural effusion.