Persistent Left Vena Cava Superior Draining Directly to the Left Atrium and Partial Anomalous Pulmonary Venous Return

History
A 55-year-old male patient (heart rate 75 bpm, body mass index 26.0 kg/sqm) suffered from progredient physical inefficiency and atypical chest pain since several months. Thoracic CT (non-ECG-gated) raised the suspicion of thrombosis of the innominate vein. There was also found a left mediastinal tubular contrast-enhanced structure which was suspected as hemiazygos continuity. The patient was referred to our hospital in order to exclude coronary artery disease as cause of the chest pain and conclusively assess the mediastinal structures. Subsequently, the patient underwent an ECG-gated chest pain CT protocol with modified contrast agent application taking into account the suspected thrombosis of the innominate vein.

Diagnosis
CT revealed a persistent left vena cava superior (PLVCS) directly draining in the roof of the left atrium at a level above the left atrial appendage. In addition, a partial anomalous venous return of the left upper pulmonary vein in the PLVCS was detected.  The innominate vein was found to represent an atretic cord. The coronary arteries had a normal anatomy without substantial stenosis. The coronary sinus was normal.

Comments
Persistent left vena cava superior (PLVCS) exists in 0.3 to 0.5% of the general population and 1.5% to 10% in patients with other congenital cardiac abnormalities. Commonly, the PLVCS enters the right atrium via the orifice of an enlarged coronary sinus which is well tolerated. The atypical entering of the PLVCS in the left atrium results in a right-to-left shunt of varying degree and consequently cause arterial unsaturation. Commonly, PLVCS is of little clinical significance and – as in the present case – patients remain asymptomatic for long-term. However, PLVCS without communication between both vena cava superior by the mean of an obliterated or thrombosed innominate vein has important clinical implications in certain situations: (a) risk of embolisation secondary to intravenous therapy administered through the left arm; (b) implantation of transvenous pacemaker; (c) placement of pulmonary artery catheter for intensive care unit monitoring without fluoroscopic guidance; (d) systemic venous access for extracorporeal membrane oxygenation; (e) orthotopic heart transplantation. DSCT permits the rapid diagnosis of congenital cardiac and extracardiac pathologies. For simultaneous evaluation of cardiac and extracardiac structures the special DSCT chest pain protocol can be used, combining a cardiac scan and a thorax scan. Simultaneous contrast application at both sided antecubital veins was found very helpful to ensure contrast agent attenuation of the upper venous system of both sides in the case of suspected thrombosis of the innominate vein and PLVCS.

Authors: Sebastian Leschka, MD, Paul Stolzmann, MD, Hans Scheffel, MD, Stephan Baumüller, MD, Florian Schmid, MD, Björn Stinn, MD, Simon Wildermuth, MD, Borut Marincek, MD, Hatem Alkadhi, MD

Figure 1 – Coronal MIP shows a vena cava superior on the right and left side (arrows). The innominate vein was found to be an atretic cord (open arrow).	Figure 2 – VR image in an left anterior oblique view. The upper left pulmonary vein enters in to the persistent left vena cava superior.
Figure 3 – Transverse MIP image at the level of the pulmonary trunk visualizes the communication (arrow) between the left upper pulmonary vein (moderate opacification) and the persistent left vena cava superior (high opacification). Figure 5 – Photograph illustrates contrast application route in the antecubital veins of both sides (thin arrows) by the use of a T-adapter (bold arrow).	Figure 4 – Coronal MIP reveals the atypical entering of the PLVCS into the left atrium (arrow) above the left atrial appendage (open arrow).