Double Trouble : Unexpected Double Superior Vena Cava Following Left Internal Jugular Central Venous Catheter Insertion
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Authors
Foran, Claire
Agarwala, Rita
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Issue Date
2026-04
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Abstract
Introduction: A persistent left-sided superior vena cava (PLSVC) is the most common thoracic cardiac anomaly, occurring in approximately 0.3% of the general population and up to 10–11% of patients with congenital heart disease. In cases of duplicated superior vena cava (double SVC), both right and left SVCs persist due to failure of regression of the embryonic left anterior cardinal vein. Although usually asymptomatic, this anatomical variant can cause concern during central venous catheter (CVC) placement when post-procedure imaging demonstrates an unexpected catheter course.
Case: A 30-year-old pregnant female with sickle cell disease presented in acute vaso-occlusive crisis, requiring reliable intravenous access for patient-controlled analgesia and transfusions. Due to difficult peripheral venous access, CVC cannulation was performed. Although right sided access was initially planned, the patient was unable to tolerate positioning due to pain; therefore, the left internal jugular vein was accessed. A post-procedure chest radiograph demonstrated an unusual left-sided mediastinal course of the catheter, rather than crossing the midline to the right SVC. Venous blood gas sampling (sO2 65.5%) and pressure waveform analysis confirmed venous placement.
Radiology consultation was sought, and review of prior CT venography from the referring hospital revealed a duplicated SVC. The patient’s left internal jugular and subclavian veins formed a left brachiocephalic vein that did not cross the midline, instead descended vertically along the left mediastinum as a persistent left SVC. This vessel coursed adjacent to the left atrium before ultimately draining into the inferior portion of the right atrium near the junction with the inferior vena cava.
As the patient was pregnant, no additional imaging was performed. The anatomical findings were communicated to interventional radiology in anticipation of insertion of a tunnelled Hickman Line.
Discussion : Recognition of thoracic venous anomalies is important during central venous access procedures. A persistent left SVC can result in an abnormal catheter trajectory on chest radiography and can initially raise concerns regarding arterial placement or malposition. Cross-sectional imaging such as CT venography is typically used to confirm the diagnosis and delineate venous drainage patterns. Awareness of this variant is crucial to prevent unnecessary line removal and to guide future vascular access planning.
Conclusions :
• Double SVC should be considered when a central line follows a vertical left mediastinal course on chest X-ray.
• Confirmation of venous placement using blood gas analysis and waveform tracing can help exclude arterial cannulation.
• Awareness and documentation of thoracic venous anomalies are essential for safe future vascular access procedures.
Description
Poster presented at South East Thames Society of Anaesthetists (SETSA) 2026 Conference