CASE 13686 Published on 23.05.2016

Isolated left-sided superior vena cava

Section

Cardiovascular

Case Type

Anatomy and Functional Imaging

Authors

Krishnakumari A. Modi1, Nitesh Shekhrajka2

1Department of Radiology,
Regionshospital Nordjylland,
Bispensgade 37,
9800 Hjørring, Denmark.
Email:krishnamodi4@gmail.com
2Department of Radiology,
Aalborg University Hospital,
Hobrovej 18-22,
9000 Aalborg, Denmark.
Patient

3 years, female

Categories
Area of Interest Veins / Vena cava ; Imaging Technique Conventional radiography, CT
Clinical History
3-year-old female patient was admitted with leukaemia and a right-sided central venous catheter (CVC) was inserted to administer chemotherapy. A control chest X-ray was performed to check the placement of CVC which couldn't be explained - an anatomical variant was suspected and CT was performed to confirm diagnosis.
Imaging Findings
Chest X-ray:

A right-sided Central Venous Catheter (CVC) can be seen with the tip at the upper border of the left main bronchus /aorto-pulmonary window. This placement could only be explained by an anatomical variant like left-sided Superior Vena Cava (SVC). A CT was performed to confirm the anatomical variant.

CT chest and abdomen:

CT confirms the presence of suspected anatomical variant. An isolated left sided SVC draining into right atrium via the coronary sinus was seen. CVC was placed in the left-sided SVC.
Discussion
Background:

Persistent left superior vena cava (PLSVC) is a rare but important congenital thoracic venous anomaly, results from the persistent left anterior cardinal vein with a prevalence of 0.3-0.5 % in the general population and about 12% in patients with congenital heart diseases. [4, 5] In 82-90% of PLSVC cases, right SVC is also present, results in duplication of SVC, but in only 10–20% cases of PLSVC, there will be isolated PLSVC, which usually drains into the right atrium via the coronary sinus without haemodynamic consequences, is therefore asymptomatic and an incidental finding on imaging studies done for unrelated purposes. [2, 1] Very rarely, LSVC may drain in the left atrium resulting in a right to left shunt. [5] Isolated PLSVC is at high risk for associated anomalies including atrial septal defect, ventricular septal defect, tetralogy of Fallot, bicuspid aortic valve, aortic coarctation, mitral atresia, and cor triatriatum [3, 5]

Clinical Perspective and outcome:

Often the frontal chest radiographs, done to evaluate positioning of central venous catheters showing unusual left-sided downward course are a first clue to PLSVC, which can be misdiagnosed as arterial, mediastinal, or pleural placement. [3, 5] PLSVC may also cause difficulty in placement of pacemakers, implantable cardioverter-defibrillator leads, and Swan-Ganz catheters because of the narrow opening from the coronary sinus to the right atrium. [3, 4] PLSVC is a relative contraindication for retrograde cardioplegia during coronary artery bypass grafting, which may be ineffective because of inadequate myocardial perfusion. [3] Lack of knowledge about anomaly can lead to complications such as arrhythmia, cardiogenic shock, cardiac tamponade, and coronary sinus thrombosis if pacemaker leads or catheters have been inserted via PLSVC. Therefore it is important that cardiothoracic surgeons, anaesthesiologists, intensivists and radiologists are aware of the anomaly before planning surgical and radiological vascular procedures. [5]

Imaging perspective:

Radiologically, LSVC should be suspected if there is a widened aortic shadow, paramediastinal bulge or a low density line along the upper left margin of the heart on a posteroanterior view which can be misdiagnosed as pathologic mass. [4] CT or cardiac MR provides direct visualization of an abnormal course of veins. [4] Agitated saline injection via the left antecubital vein (Bubble study) and performing trans-thoracic echo is a safe, harmless and inexpensive test that can help detect LSVC when suspected. [4]

Teaching points:

Being a rare anomaly, it takes a high index of suspicion but should be considered on detecting dilated coronary sinus on echocardiography or left paramediastinal bulge on chest radiographs.
Differential Diagnosis List
Isolated left-sided superior vena cava.
Malpositioning of venous catheters
Left paramediastinal pathological mass
Final Diagnosis
Isolated left-sided superior vena cava.
Case information
URL: https://www.eurorad.org/case/13686
DOI: 10.1594/EURORAD/CASE.13686
ISSN: 1563-4086
License