Exclusion of an Azygos Vein Varix With a Covered Stent

Abstract

An azygos vein varix was incidentally discovered in a 26-year-old man. Owing to the potential risk of pulmonary emboli, we implanted a covered stent in the superior vena cava, effectively excluding the varix. Eighth months later, the varix was thrombosed and involuted. (Level of Difficulty: Advanced.)

Graphical abstract

History of Presentation

A 26-year-old male patient presented with tachycardia and shortness of breath after drinking 2 caffeinated energy drinks. An initial finding of a possible mass on chest x-ray film (Figure 1) led to computed tomography angiography (CTA), which demonstrated azygos vein enlargement. Subsequently, he was referred to us for evaluation.

Learning Objectives

• •To describe a patient with an azygos vein varix, who presented with a right perimediastinal mass and without evidence of thrombosis or a pulmonary embolism.
• •To understand the therapeutic options for an azygos vein varix, including surgery and several interventional techniques.

Figure 1.

Chest X-Ray Film Showing the Right Pulmonary Density

(A) Anteroposterior view. (B) Lateral view. Arrows indicate right pulmonary density.

Past Medical History

The patient reported previous good health other than a childhood history of occasional right-sided chest noted with running.

Differential Diagnosis

A right pulmonary mass can be a primary pulmonary tumor, an infection (which would particularly include tuberculosis), a pulmonary contusion from trauma, or a vascular abnormality.

Investigations

The initial chest CTA showed a mass along the right mediastinum in the region of the azygos vein that filled with contrast and communicated with the superior vena cava (Figure 2). A contrast-enhanced magnetic resonance venogram demonstrated that the right mediastinal and pulmonary mass was a 4.3 cm × 4.5 cm × 2.3 cm azygos vein varix, which received flow from a normal-appearing superior vena cava anteriorly and a small proximal azygos vein caudally. There was no evidence of anomalous systemic or pulmonary arterial or venous connections to the varix. Our multispecialty conference recommended a cardiac catheterization for further imaging and possible intervention.

Figure 2.

Computed Tomography Angiography Images of the Azygous Vein Varix

(A) Anteroposterior view. (B) Lateral view. (C) Axial view. RA = right atrium; SVC = superior vena cava; V = varix.

Management

At catheterization, the large azygos vein varix was confirmed by angiography with a size estimated at 5 cm × 2.5 cm × 2.5 cm (Figures 3A and 3B, Videos 1, 2, 3, and 4). The diameter of the azygos vein, as it entered the superior vena cava, was 16 mm. The superior vena cava diameter was 19 to 22 mm. Hemodynamics were normal, including normal pulmonary arterial pressure, and no evidence of right-to-left or left-to-right shunts. Right pulmonary angiography showed no pulmonary arterial or venous connections with the varix. The azygos vein, proximal to the varix, did not fill during varix angiography and could not be entered with a Wholey wire (Medtronic, Minneapolis, Minnesota). A 4.5 mm Cheatham Platinum covered stent (NuMed, Hopkinton, New York) was deployed in the superior vena cava with a 24-mm Balloon in Balloon catheter (B. Braun, Melsungen, Germany). After the intervention, superior vena cava angiography showed no further flow into the varix (Figures 3C and 3D, Videos 5 and 6); additionally, pulmonary angiography showed no compression of the right pulmonary artery or the right upper pulmonary veins. The patient was discharged on daily warfarin with an international normalized ratio goal of 2.0 and daily aspirin 325 mg, until the therapeutic international normalized ratio was achieved.

Figure 3.

Angiographic Images Before and After Stent Placement

Baseline angiogram in the varix (V): (A) anteroposterior view and (B) lateral view. Images after delivery of the covered stent in the superior vena cava (SVC): (C) anteroposterior view and (D) lateral view. S = stent.

Follow-Up

Six months later, the warfarin was discontinued, and he was maintained on a daily aspirin 325 mg. Eight months after catheterization, a chest CTA showed thrombosis and partial involution of the varix (Figure 4), a wide-open superior vena cava, and no other venous abnormalities.

Figure 4.

Reconstructed Computed Tomography Angiography Images Before and 8 Months After the Intervention

Original computed tomography angiography: (A) anteroposterior view and (B) lateral view. Follow-up CTA: (C) anteroposterior view and (D) lateral view. A = azygos vein; other abbreviations as in Figures 2 and3.

Discussion

Galen was the first to name the “azygos” vein, which in Greek means unpaired (1). The azygos system is a venous network responsible for draining the thoracic wall and upper lumbar region and supplies collateral circulation between the superior vena cava and the inferior vena cava (Figure 5). The H-shaped configuration consists of the azygos, hemiazygos, accessory hemiazygos veins, and the left superior intercostal vein (2).

Figure 5.

Diagrammatic Representation of Systemic Venous Return

Anomalies of the azygos vein are rare and often incidentally identified on thoracic imaging (2). Congenital azygous vein abnormalities include absence of the azygos vein, lateral azygos vein associated with an azygos lobe of the right lung, interrupted inferior vena cava with azygos continuity to the superior vena cava, and partial anomalous pulmonary venous return of 1 of more veins to the azygos vein. Among acquired azygos vein abnormalities are enlargement due to right atrial hypertension, inferior vena cava obstruction or portal hypertension, abnormal size or direction of flow from a superior vena cava obstruction, and extrinsic displacement from neoplasms, mediastinal lymph node enlargement, or aortic aneurysm with or without dissection (2).

Marked enlargement of a portion of the azygos vein has been referred to as a varix (3,4) or an aneurysm (5, 6, 7, 8, 9, 10). Some authors suggest that a venous varix and a venous aneurysm have different vessel wall histology (5), with varices having increased fibrous tissue and medial thickening and aneurysms showing reduced number and size of muscle and elastic fibers, intimal hyalinization, fragmentation of the internal elastic lamella, and excessive fibrous connective tissue. In the absence of pathologic confirmation, we have chosen varix. Varices can be congenital or acquired. The acquired form is most often due to high central venous pressure, cardiac decompensation, portal hypertension, arteriovenous fistula, pregnancy, external compression, or trauma (5). Our patient had no evidence of the acquired etiologies; thus, we deemed it a probable congenital azygos vein varix.

Because of their rarity, management of azygos vein varices is controversial (5). Some recommend conservative management (6); nevertheless, patients have presented with intraluminal thrombus formation or severe pulmonary embolism, likely originating from the varix (5, 6, 7). Azygos vein varix rupture is another possible adverse outcome; however, there are no reports of rupture, likely secondary to low-pressure venous environment.

There are reports of surgical treatment of azygos vein varices with good results and without recurrence (8). Cardiac catheter intervention has also been described. Techniques include coil occlusion of the varix (9), Amplatzer device placement in the azygous vein on both sides of the varix (4,10), and covered stent implantation within the varix (7).

In our patient, the varix was considered to be too large for intracavitary coil or device implantation. The proximal azygous was very small and could not be entered. Therefore, the decision was made to place a covered stent in the superior vena cava with the aim of completely occluding the connection of the azygous vein and the superior vena cava. Technically, implantation was straight forward utilizing common techniques used by congenital cardiac interventionists. Warfarin anticoagulation was given for 6 months to allow for stent endothelialization. Eight months later the patient remained asymptomatic, and follow-up CTA showed obliterative thrombosis, partial involution of the varix, and no other venous abnormalities.

Conclusions

We describe successful covered stent exclusion of an azygos vein varix in a young man with reassuring findings on CTA imaging 8 months later. This technique offers an additional method of preventing potential embolic events from the varix to the pulmonary circulation.

Author Relationship With Industry

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.

Appendix

Video 1

Angiogram inside the varix. Anteroposterior view.

Video 2

Angiogram inside the varix. Lateral view.

Video 3

Superior vena cava angiogram. Anteroposterior view.

Video 4

Superior vena cava angiogram. Lateral view.

Video 5

Superior vena cava angiogram after stent implantation. Anteroposterior view.

Video 6

Superior vena cava angiogram after stent implantation. Lateral view.