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Radhika Uppal1, Nikunj R Shekhada2, Sairam Palaparthi3, Suman Vyas4, Byalal Raghavendrarao Jagannath3
1 Department of Pediatric Cardiology, Star Hospital, Hyderabad, Telangana, India
2 Department of Cardiac Surgery, Star Hospital, Hyderabad, Telangana, India
3 Department of Paediatric Cardiac Surgery, Star Hospital, Hyderabad, Telangana, India
4 Department of Paediatric Cardiology, Star Hospital, Hyderabad, Telangana, India
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Date of Submission11-Nov-2021Date of Decision19-Jan-2022Date of Acceptance15-Jun-2022Date of Web Publication06-Jan-2023
Abstract
What do we call a vascular structure that is in the left pneumopericardial space, drains systemic venous blood, and the total pulmonary venous return, into the right atrium, through a dilated coronary sinus (CS)? Can we preserve the CS drainage while correcting the total anomalous pulmonary venous connection?
Keywords: Left superior vena cava, left vertical vein, unusual total anomalous pulmonary venous connection
How to cite this article: Introduction 
Persistent left superior vena cava (LSVC) is an uncommon vascular anomaly but the most prevalent thoracic venous anomaly that begins at the junction of the left subclavian and internal jugular veins and travels across the left half of the mediastinum and opens into coronary sinus (CS). LSVC is asymptomatic and often discovered by chance during diagnostic and therapeutic procedures. On the other hand, in supracardiac total anomalous pulmonary venous connection (TAPVC), pulmonary veins instead of draining into left atrium (LA) form common pulmonary confluence, which ascends as left vertical vein (LVV) and opens at superior vena cava, and innominate vein junction with or without obstruction. Hence, both LSVC and LVV occupy the left pleuropericardial space; however, it is rare to see LVV carrying pulmonary venous blood draining via a persistent LSVC into dilated CS. The difference between an LSVC and an LVV on echocardiography is the direction of flow which is cephalad, in the latter. Can we preserve the CS drainage while correcting the total anomalous pulmonary venous connection?
Case Report After taking informed written consent of parents, a 4 month old female weighing 2.9kg who presented with failure to thrive and heart failure was admitted to undergo surgical correction for TAPVC. Two-dimensional (2D) echocardiography revealed an obstructed supracardiac TAPVC. The narrow caliber of the innominate vein [[Figure 1] and Video 1 [Additional file 1]], with a dilated LVV, prompted a computed tomography (CT) scan. The ct scan [Figure 2] showed all 4 pulmonary veins forming a common draining channel, i.e lvv, which was ascending superiorly and passing posterior to the left bronchus to drain into upper part of dilated lsvc [[Figure 3], Video 2 [Additional file 2]]. The lsvc was inturn opening caudually in to right atrium via dilated coronary sinus. The LSVC was draining into the right atrium (RA) via a dilated CS. There was a communicating innominate vein which was not dilated.
At surgery, we were able to trace this channel, isolate it separately from the confluence, and ligate it; a regular confluence to the LA anastomosis was done to establish normal pulmonary venous return. At the same time, the continuity of the LSVC into the RA was still maintained [[Figure 4] and Video 3 [Additional file 3]]. Postoperative 2D echocardiography [[Figure 5] and Video 4 [Additional file 4]] showed good unobstructed systemic and pulmonary venous drainage. The child had an uneventful recovery and was discharged home on the 10th day.
Figure 1: (a) Two-dimensional echocardiogram showing bald left atrium and common pulmonary venous confluence posterior to left atrium. (b) Two-dimensional echocardiogram showing left vertical vein and nondilated innominate vein. LVV: Left vertical vein
Figure 2: Computed tomography scan showing the anatomy total anomalous pulmonary venous connection and the vertical vein, left superior vena cava and the right superior vena cava, note the normal-sized and oriented confluence, narrow innominate vein, dilated intrapleural/vertical vein or left superior vena cava. RT-SVC: Right superior venacava, RTSPV: Right superior pulmonary vein, RTIPV: Right inferior pulmonary vein, LT-SVC: Left superior venacava, LTSPV: Left superior pulmonary vein, LTIPV: Left inferior pulmonary vein
Figure 3: Operative photograph showing the left superior vena cava continuing down as the coronary sinus, and the left vertical vein looping around the left pulmonary artery, to join the left superior vena cava
Figure 4: The postprocedure ligated left vertical vein and left superior vena cava continuing as the coronary sinus
Figure 5: Echocardiogram done postoperative showing a wide-open anastomosis of the confluence to the left atrium and dilated coronary sinus. CS: Coronary sinus Discussion The LVV of a supracardiac TAPVC is often indistinguishable from a normal LSVC. Both have an intrapericardial component and an extrapericardial component, both use the left cardinal vein,[1] and both are in the pleuropericardial space, anterior to the left pulmonary artery and associated with an innominate vein, and drain into the RA. While the LVV originates from the confluence and carries oxygenated blood to the RA, the direction of flow being cephalad, the LSVC carries deoxygenated blood and flows inferiorly to open into the CS. LSVC is usually as a part of the bilateral SVC, in which case there is no communicating vein or the communication may be via small veins. TAPVC into the CS is not associated with an LSVC, and TAPVC with LVV does not drain into the CS.[2] Supracardiac TAPVC generally has a dilated innominate vein,[3] giving the classic snowman appearance. At surgery, the vertical vein is ligated just superior to the confluence, or close to its drainage into the innominate vein, to prevent a residual left-to-right shunt.
In any surgery, it is important to preserve the natural flow patterns and ensure correction of the defects completely. In TAPVC to the CS, especially with an LSVC, the preservation of the LSVC results in desaturation. Ligation of the LSVC in the absence of communicating vein means dependence on the venous collateral, while a small communicating vein means potential obstruction to the venous return from the left upper limb and head. Alternative is to perform an LSVC to RA appendage, with its attendant increase in pump time, potential need for other tissue, and possibility of occlusion in long term. This is a favorable anatomy where the continuity of the LSVC into CS is preserved and TAPVC is routed to the LA. Ideally, the LVV should have been divided. This also supports the view that LVV is embryologically separated from the LSVC and is actually a midline structure. The systemic communication of the TAPVC in this case is to a normal LSVC of a bilateral SVC system. Recognition is aided by tracing the direction of flow, which would be like a normal LSVC into a dilated CS, absence of a dilated innominate vein, and a bald LA, with other features of TAPVC. The confirmation is by CT imaging, which also would enable surgical planning.
Conclusion This case report demonstrates the different embryologic origins of LSVC and LVV; however, the LVV may use the cephalad segment of the LSVC. It is a rare vascular anomaly where the LSVC can be preserved, during the repair of the TAPVC.
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Conflicts of interest
There are no conflicts of interest.
References 
Correspondence Address:
Dr. Byalal Raghavendrarao Jagannath
Department of Paediatric Cardiac Surgery, Star Hospital 2-596/5, Banjara Hills Road, Number 10, Krishna Nagar, Banjara Hills, Hyderabad - 500 034, Telangana
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/apc.apc_215_21
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