Clinical significance of persistent left superior vena cava diagnosed in fetal life

To determine the prevalence and clinical significance of persistent left superior vena cava (PLSVC) in fetuses with and without cardiac and extracardiac anomalies.

Charts and recorded images were reviewed from high-risk patients who underwent fetal echocardiography between January 2000 and December 2005. This retrospective study included 54 fetuses with confirmed PLSVC who were diagnosed based on the presence of an additional vessel identified to the left of the pulmonary artery in the three-vessel view of the heart. Associated congenital heart defects (CHDs), extracardiac abnormalities, including first trimester nuchal translucency (NT) thickness, and fetal/postnatal outcome were analyzed.

Of 5,737 referrals, 5,233 had a normal heart, and PLSVC was observed in 10 of these fetuses (0.2%; Group 1). CHDs were present in 504 and PLSVC was observed in 44 of these cases (9%). In the latter group, 18/44 (41%) fetuses had heterotaxy syndrome (Group 2) where the most common structural heart defects were atrioventricular septal defect and double-outlet right ventricle. Fetuses without heterotaxy syndrome (Group 3) accounted for 26/44 (59%) cases of CHDs associated with PLSVC. In this group of fetuses the most common CHDs were left outflow tract obstructive defects and conotruncal anomalies. Increased NT was observed in 29%, without differences among the three groups. The survival rates among fetuses in Groups 1, 2 and 3 were 100%, 44% and 50%, respectively. After excluding patients who underwent pregnancy termination, there were no significant differences in the survival rates among the groups, probably due to the small size of the samples. CONCLUSIONS PLSVC is associated with CHDs. The identification of PLSVC should prompt a thorough examination of the fetus to identify additional cardiac and extracardiac anomalies. The prognosis of affected fetuses largely depends on whether or not the PLSVC is associated with a CHD.