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ABSTRACT
Persistent left superior vena cava (SVC) without the right SVC is very rare and occurs in 0.07%–0.13% of patients with congenital heart defects. An enlarged coronary sinus detected during cardiac examination in the prenatal period is the first finding that raises suspicion for this anomaly. In this report, a patient was presented who was referred with the prediagnosis of cor triatriatum sinister in the antenatal period and diagnosed with isolated persistent left SVC.
INTRODUCTION
Persistent left SVC is the most common variation of the thoracic venous system1. It is found in 0.3%–0.5% of the general population and 4%–8% in those with congenital heart disease (CHD)2-5. In the embryonic period, the anterior cardinal veins provide venous drainage of the cephalic region and upper extremity. Except for a small portion forming the left superior intercostal vein, the left anterior cardinal vein regresses by the eighth week of embryogenesis. Failure of this regression results in persistent left SVC6. In most cases, the right and left SVC coexist. Persistent left SVC without the right SVC, also called isolated persistent left SVC, is very rare and occurs in 0.07%–0.13% of patients with congenital heart defects with visceroatrial situs solitus. An enlarged coronary sinus detected during cardiac examination in the prenatal period is the first finding that raises suspicion for this anomaly7. Diagnosis is made with three vessels view, which is one of the standard cardiac examination sections, and an additional vessel to the left of the pulmonary artery and ductus arteriosus in the tracheal image or indirectly draining into the left or right atrium. The wideness of the coronary sinus may confuse the diagnosis with cor triatriatum sinister during fetal cardiac evaluation. Isolated persistent left SVC is generally considered a benign condition. When present with cardiac and extracardiac anomalies and chromosomal anomalies, perinatal and neonatal outcomes are adversely affected8.
CASE
In the fetal echocardiographic evaluation performed during the 33rd week of pregnancy in a female patient who was sent from an external center with the prediagnosis of cor triatriatum sinister, it was observed that the coronary sinus was wide. In the evaluation of the region where the coronary sinus ostium is located, it was observed that the coronary sinus was wide and there was an additional structure to the left of the pulmonary artery in three vessel view (Video S1 and S2). As a preliminary diagnosis, persistent left SVC was suspected alongside cor triatriatum sinister. The diagnosis was confirmed as isolated persistent left SVC by echocardiography performed in the postnatal period and contrast echocardiography performed with agitated saline (Video S3 and S4).
CONCLUSION-DISCUSSION
Persistent left SVC without right SVC (isolated persistent left SVC) is a very rare venous malformation. During normal fetal development, the left anterior venous cardinal system regresses and lags the coronary sinus and Marshall ligament. Failure of the left anterior cardinal vein to close results in persistent left SVC. Generally, persistent left SVC is associated with right SVC and drains into the right atrium through a dilated coronary sinus. When developmental arrest occurs at an earlier stage, the absence of coronary sinus is seen and the persistent left SVC drains into the left atrium. This venous malformation, either isolated or associated with right SVC, does not itself cause hemodynamic disturbance and is usually diagnosed incidentally. In the study of Ari et al., after the retrospective evaluation of 2663 patients with CHD, between 2005 and 2012, persistent left SVC was found in 88 (3.3%) patients, while isolated persistent left SVC was found in 5 patients (0.001%) 5.
Contrary to most reported cases of isolated persistent left SVC,9 the case presented herein was a rare condition due to the presence of situs solitus and right SVC agenesis and no associated CHD, and it was diagnosed by differential diagnosis from cor triatriatum in the fetal period.
REFERENCES
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