Prenatal diagnosis of persistent left superior vena cava: a retrospective study of associated congenital anomalies

Persistant Left Superior Vena Cava with and Without Right Superior Vena Cava: Significance of Prenatal Diagnosis

This study aims to define the associated anomalies with PLSVC, and to compare single PLSVC and bilateral superior vena cava in terms of accompanying anomalies and pregnancy outcomes. This was a retrospective study of the fetuses diagnosed with single and/or bilateral SVC at a tertiary fetal medicine center during 8 years. We detected 16 cases of single PLSVC and 84 cases of bilateral SVC. We found an association between the PLSVC and cardiac and extracardiac anomalies. Comparison between single PLSVC and BSVC cases revealed significant differences in the occurrence of heterotaxy and right isomerism. The study highlights the importance of prenatal diagnosis in PLSVC cases. Isolated PLSVC with situs solitus may be considered a benign finding, but larger studies are needed to understand the clinical implications of PLSVC in relation to chromosomal anomalies. Routine screening protocols should include three-vessel and trachea views to detect PLSVC.

Persistent Left Superior Vena Cava Significance in Prenatal Diagnosis—Case Series

The persistent left superior vena cava (PLSVC) is a congenital heart anomaly reported in 0.3–0.5% of the general population and can be associated with congenital heart diseases in up to 8% of cases. Prenatal identification of PLSVC is important to prompt an extended cardiac and extracardiac fetal examination. We retrospectively reevaluated anomaly scans performed in our unit in a 2-year interval according to the national guidelines to evaluate the incidence of PLSVC and its association with prenatal morbidity. In our population, the incidence of PLSVC was 0.31%, and we found a low association with cardiac and extracardiac anomalies. The standard sections (three-vessel and trachea view, four-chamber view and outflow tract’s view) are insufficient to exclude cardiac anomalies whenever PLSVC is found. In our case series, only one newborn required postnatal surgery for total pulmonary vein anomaly, and at 2 years of life all babies had a normal evolution. Prenatal diagnosis of PLSVC can raise counseling issues; therefore, awareness of its good outcome when isolated and need for an extended examination to rule out other anomalies is very important.

Clinical significance of prenatally diagnosed persistent left superior vena cava

AIMS

The aim of our study was to investigate the persistent left superior vena cava (PLSVC) cases diagnosed in the prenatal period in our clinic and to compare the obstetric and genetic outcomes of isolated PLSVC cases with cases accompanied by other cardiac or extracardiac anomalies.

METHODS

The cases diagnosed as PLSVC between January 2015 and January 2019 in our perinatology clinic were evaluated retrospectively. Patients were divided into two subgroups as isolated PLSVC and PLSVC accompanied by another anomaly. Furthermore, patients with extra anomalies were divided into three groups which are cardiac anomaly, extracardiac anomaly and those with both. The groups were compared in terms of genetic results and obstetric outcomes.

RESULTS

89 patients were included in our study. Cases with positive pregnancy outcomes were significantly higher in the isolated PLSVC group than with extra anomaly group (p<0.001). No karyotype anomaly was observed in the isolated group. Pregnancy results were significantly worse (postpartum demise, termination of pregnancy, in utero demise) in with both cardiac and extracardiac anomalies group (p<0.001). There was no significant difference between the groups in terms of karyotype results (p=0.535).

CONCLUSION

The diagnosis of PLSVC has gained importance and it can be made easier due to the fact that anatomic imaging can be performed in more detail. The isolated PLSVC cases have a very good prognosis. Obstetric outcomes vary according to the accompanying anomaly.

Autopsy findings of an isolated persistent left superior vena cava in an intrauterine dead fetus

Persistent left superior vena cava (PLSVC) is one of the cardiac system abnormalities with a 0.3-0.5% incidence and caused by inadequate obliteration of the left anterior cardinal vein during embryonic development. Prognosis of PLSVC is generally assumed to be good if it is not accompanied by other cardiac system abnormalities. During the routine ultrasound control of a patient at 25th week of pregnancy at the Obstetrics and Gynecology Department of Mersin University, PLSVC anomaly was detected in an intrauterine fetus. Then, intrauterine death occurred and after removal of the deceased fetus, PLSVC diagnosis was confirmed by autopsy. According to the autopsy findings, right superior vena cava (SVC) and azygos vein were found in normal course. PLSVC opened into the right atrium via enlarged coronary sinus. There was no connection between the two SVCs. On the left side of posterior mediastinum, instead of hemiazygos or accessory hemiazygos veins, a vein symmetrical to azygos was opened into PLSVC, similar to the one on the right. No other cardiac anomaly associated with PLSVC or any other pathology in the other parts of body that could be responsible for death was discovered during autopsy. There was no evidence indicating that PLSVC played any role in intrauterine exitus of the present case. However, as mentioned in the literature, the ectopic beats in the atrium wall of patients with isolated PLSVC and enlarged coronary sinus may lead to pathologies in the conduction system of the heart. Considering the intrauterine death of an isolated PLSVC case associated with cardiac conduction pathologies, we recommend that the common assumption of 'isolated PLSVC is not associated with death' should be reviewed by studies on large series and even intrauterine cases should be closely monitored for cardiac arrhythmia.

Left Superior Vena Cava in the Fetus: A Rarely Isolated Anomaly

The frequency of chromosomal anomalies among fetuses with isolated persistent left superior vena cava (PLSVC) is still debated. The objective of the present study was to assess the prevalence of genetic and morphological anomalies identified in fetuses with PLSVC. We conducted a single-center retrospective study including all fetuses diagnosed with a PLSVC between 2010 and 2017. PLSVC was categorized as isolated or associated according to antenatal diagnosis of associated congenital heart defects, hypoplastic aortic isthmus, abnormal venous/arterial connections, and extracardiac anomalies. Among 229 fetuses diagnosed with PLSVC, 39 cases (17%) were strictly isolated and no syndromic/genetic anomaly or aortic coarctation was diagnosed. Seventy-two fetuses had a cardiovascular defect with a rate of genetic anomalies of 22%, 29 had an extracardiac malformation, and 89 had both an extracardiac and a cardiovascular defect. Among fetuses with abnormal development of the arterial/venous system as the only associated anomaly such as aberrant right subclavian artery or absent ductus venosus, 22% had a genetic anomaly. Overall, sixty-five fetuses or infants had a genetic concern, including 23 aneuploidies, 15 pathogenic micro-deletions/duplications, and 5 variants of unknown significance; 12 patients had VACTERL association, and 12 heterotaxy syndrome. Seven infants had an aortic coarctation diagnosed at birth.In conclusion, a thorough prenatal ultrasound examination is paramount, and the identification of variants of the venous/arterial system in addition to PLSVC should raise suspicion for genetic or morphologic abnormalities. Invasive prenatal diagnosis with array-CGH should be offered when PLSVC is non-isolated, after a detailed ultrasound evaluation in a tertiary center.