Anomalous Left-sided Superior Vena Cava with Cephalad Flow.

The case of a 24-year-old male with complaints of migraine headaches was referred for echocardiography. The rest of medical history was unremarkable. Agitated saline contrast bubble study showed evidence of a right to left intracardiac shunt, probably secondary to a patent foramen ovale. Results of a transesophageal echocardiogram suggested the possibility of an anomalous venous circulation and eventually identified as anomalous left-sided superior vena cava with cardiac magnetic resonance imaging.

INTRODUCTION

In this case report, a patient with complaints of migraine headaches was referred for echocardiography. Agitated saline contrast bubble study revealed the presence of a right to left intracardiac shunt. On transesophageal echocardiography an intact interatrial septum was identified. However, contrast bubbles were seen in the left atria arising from the left superior pulmonary vein after injection of agitated saline from the patient's left arm, a finding not noted upon injection into the right arm.

We describe the thorough evaluation that demonstrated the presence of an anomalous left-sided vena cava with cephalad flow.

CASE REPORT

A 24-year-old male with an unremarkable medical history is referred for echocardiography with complaints of migraine headaches, and although normal cavity dimensions, biventricular and valvular functions were noted, agitated saline contrast bubble study showed evidence of a right to left intracardiac shunt, probably secondary to a patent foramen ovale (PFO) [Figure 1].

Figure 1

Transthoracic echocardiogram demonstrating rapid presence of agitated saline bubbles in the left ventricle (arrows), suggesting intracardiac right to left shunt. RV: Right ventricle, LV: Left ventricle, RA: Right arm, LA: Left arm

Transesophageal echocardiography was then performed but failed to show any evidence for either a PFO or an atrial septal defect (ASD). However, contrast bubbles were seen in the left atria after injection of agitated saline from the patient's left arm. On closer inspection, the bubbles seemed to arise from the left superior pulmonary vein, a finding that was not noted upon injection into the right arm on the previous study. These findings strongly suggested anomalous venous circulation of the thoracic vessels [Figure 2].

Figure 2

Transesophageal echocardiogram demonstrating rapid presence of agitated saline bubbles in left upper pulmonary vein. LA: Left arm, LUPV: Left upper pulmonary vein

Cardiac computed tomography demonstrated a structure parallel to the aorta, coursing from the left upper pulmonary vein (LUPV) toward the left subclavian vein, suggesting either a left-sided superior vena cava (SVC) or less likely a partial anomalous pulmonary vein [Figure 3]. Subsequent cardiac magnetic resonance with phase contrast cardiac imaging was then performed which demonstrated cephalad blood flow within structure [Figure 4]. This finding most likely represents a left-sided SVC despite the highly unusual cephalad blood flow and the caudal attachment to LUPV.

Figure 3

Computed tomography angiogram demonstrating anomalous connection between the left upper pulmonary vein and the left subclavian vein (arrow). SVC: Superior vena cava, AAo: Ascending aorta

Figure 4

Static magnetic resonance phase contrast imaging demonstrating black (cephalad) flow in the accessory structure lateral to the descending aorta (arrow). SVC: Superior vena cava, AAo: Ascending aorta, DAo: Descending aorta

DISCUSSION

Approximately 2% of patients demonstrate abnormalities of the major thoracic venous vessels in the absence of otherwise significant structural heart disease.[1] Interestingly, both left-sided SVC and partial anomalous pulmonary venous return occur in a frequency of approximately 0.2–0.6%. These entities are often confused as they both appear on routine imaging as an accessory structure lateral and parallel to the aortic arch.

Although a left-sided SVC will typically terminate in the coronary sinus owing to its embryology as a left common cardinal vein remnant, caudal attachments to the left atrium have been described.[2] Typically, the left-sided SVC demonstrates caudal flow and the anomalous pulmonary vein will demonstrate cephalad flow.[3] Partial anomalous pulmonary venous drainage is frequently associated with other congenital heart disease, most commonly an ASD, in 70% of patients.[4] Typically, both of these conditions are incidental findings detected during radiography or during central venous line or device placement.

The relationship between patient's anatomy and his chief complaint of migraine headaches remains unclear.

In summary, even though a left-sided SVC will typically terminate in the coronary sinus owing to its embryology as a left common cardinal vein remnant, caudal attachments to the left atrium demonstrating caudal flow and the anomalous pulmonary vein will demonstrate cephalad flow. However, this case illustrates an anomalous left-sided vena cava with cephalad flow. Since both these entities are often confused as they both appear on routine imaging as an accessory structure lateral and parallel to the aortic arch, we want to bring to the attention of clinicians involved with cardiac imaging interpretation an unusual case.

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Conflicts of interest

There are no conflicts of interest.