Systematic review and meta-analysis on persistent left superior vena cava on prenatal ultrasound: associated anomalies, diagnostic accuracy and post-natal outcome

OBJECTIVES: The aims of this systematic review were to quantify the prevalence of chromosomal anomalies in fetuses with persistent left superior vena cava (PLSVC), to assess the strength of association with coarctation of aorta and to ascertain the diagnostic accuracy of antenatal ultrasound in correctly identifying isolated cases. METHODS: Medline, Embase, Cinhal and Cochrane databases were searched from 2000 utilizing combinations of key words "left superior vena cava" and "outcome". Two authors reviewed all abstracts independently. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale for cohort studies. The prevalence of the following outcomes was analysed: chromosomal abnormalities, associated intra-cardiac (ICA) and extra-cardiac (ECA) anomalies diagnosed pre-natally, additional ICA and ECA detected only at post-natal imaging or clinical evaluation but missed at prenatal imaging, association with coarctation of aorta. Meta-analyses of proportions were used to combine data. RESULTS: 2708 articles were identified and 13 included in the systematic review (501 fetuses). Associated ICA and ECA were detected at the scan in 56.6% (95% CI 40.5-72.0) and 37.8% (95% CI 31.0-44.8) of the cases, respectively. Chromosomal anomalies occurred in 12.5% (95% CI 9.0-16.4) of the cases in the overall population of fetuses with PLSVC and in 7.0% (95% CI 2.7-13.0) in isolated cases. Additional ICA and ECA were detected only after birth and missed at ultrasound in 2.4% (95% CI 0.5-5.8) and 6.7% (95% CI 2.2-13.2) of the cases, respectively. Coarctation of aorta was associated with isolated PLSVC in 15.4% (95% CI 8.1-24.3) of the cases. CONCLUSIONS: PLSVC is commonly associated with ICA, ECA and chromosomal anomalies. The strength of this association is weaker in case of isolated finding. Fetuses with isolated PLSVC should be followed-up trough pregnancy in order to rule out coarctation. As most of the data are derived from high-risk pregnancies, the rates of associated abnormalities are probably higher than in the general population of fetuses with LSVC, for which more data are needed