Treatment of upper extremity venous aneurysms with a polytetrafluoroethylene-covered stent

Introduction

Venous aneurysms develop as a solitary dilatation without an associated arteriovenous malformation or a pseudoaneurysm. A retrospective analysis of nearly 2000 patients over a 22-year period found 39 venous aneurysms in 30 patients. ¹ Of these, 4 (10.3%) were seen in the upper extremity, 30 (76.9%) in the lower extremity, and 5 in the internal jugular vein (12.8%). Aneurysms were most commonly seen in the lower extremities, with only four in the axilla and five in the internal jugular vein. ¹

Aneurysm location strongly dictates presentation and management. While the deep veins of the leg are often present with pain, swelling, or appearance of masses, the aneurysms involving the head and neck are often asymptomatic. Surgical resection is warranted for both lower extremity aneurysms and abdominal aneurysms due to the increased risk of developing deep vein thrombosis, pulmonary embolism, or rupture. In contrast, head and neck aneurysms such as the subclavian vein are only addressed if they become symptomatic, or for cosmesis. ²

In review of the literature, only a handful of subclavian vein aneurysms have been reported. Of those identified, the only management options were surgical excision or conservative observation. ² This case describes a patient with a subclavian vein saccular aneurysm successfully treated endovascularly with a Viabahn® stent (W.L. Gore & Associates, Newark, DE) followed by subsequent excision.

Case report

We present the case of a 56-year-old female who initially presented to the vascular office with complaint of a persistent right supraclavicular mass increasing in size and causing discomfort when bending forward. Her medical history was significant for mental retardation, hyperlipidemia, hypertension, thyroid disease, and eczema. There was no history of trauma or instrumentation to the right chest or neck.

On physical examination, an 8 × 8 cm palpable mass was noted between the right clavicle and the deltoid muscle. The mass was firm with limited mobility on palpation. The patient was obese with a body mass index of 34 and suffered from diffuse eczema involving the upper and lower extremities. The remainder of the physical examination was within normal limits. A computed tomography (CT) scan with contrast demonstrated the presence of a saccular aneurysm of the right subclavian measuring 5 × 4 cm, containing a large intramural thrombus.

Based on continuing symptoms, increasing aneurysm size, and concern for thrombosis of the subclavian vein, the decision was made for intervention. After discussion with the family and patient regarding the risks of performing an open aneurysm resection, the decision was made to attempt an endovascular approach. The intra-operative venogram confirmed the presence of a tortuous vein partially stenosed by the large aneurysm, and the presence of intramural clots (Figure 1). An 11 mm × 10 cm Viabahn® stent was deployed successfully across the aneurysm, demonstrating adequate coverage and exclusion of the aneurysm on completion venogram. OPEN IN VIEWER

Three weeks after discharge, the patient continued to demonstrate unresolved symptoms with a persistent supraclavicular mass and was scheduled for the resection of her aneurysm. A 4-cm incision was made in the supraclavicular region, 1 cm above the clavicle. Careful dissection was performed through the platysma to expose the aneurysm, which was found to be completely thrombosed (Figure 2). The base of the aneurysm was identified, and proximal and distal control of the subclavian vein was obtained. The aneurysm sac was opened and the clot was evacuated. The aneurysmorrhaphy was completed over a Satinsky clamp with a 3-0 Vicryl® stitch. Lastly, a large fatty mass was found near the aneurysm, which was excised and sent to pathology. OPEN IN VIEWER

Discussion

While uncommon, venous aneurysms have been found in the lower extremities, mediastinum, abdomen, and various vessels of the head and neck. The aneurysm location is important as it can dictate both clinical course and management. Venous aneurysms located in the deep veins of the lower extremity are known for the development of deep vein thrombosis or pulmonary embolism, despite the use of Coumadin. ³ Thromboembolic complications and even rupture have been reported in superior vena cava (SVC) aneurysms.^2,4 Inferior vena cava (IVC) aneurysms have also been reported to result in a pulmonary embolus caused by a thrombus located in the IVC. ⁵ In both IVC and SVC aneurysms, surgical excision can be performed to prevent these embolic complications.^3,5

Venous aneurysms involving the head and neck tend to be asymptomatic, and when observed, follow a benign course. ² In our case, the decision to proceed with surgery was made based on patient discomfort, growing size of aneurysm, and for cosmesis.

Venous aneurysms are less common compared to their arterial counterparts and often can be misdiagnosed. Gillespie reported that 89% of superficial lower extremity venous aneurysms were misdiagnosed as an inguinal hernia or painful mass. ¹ Buehler et al. ⁶ presented a case of brachiocephalic vein aneurysm that was initially described as a cystic and solid mass such as a thymoma, lymphoma, or teratoma. The suspected mass underwent needle biopsy, and fortunately, a sample was taken from the thrombus attached to the wall of the aneurysm. Various diagnostic techniques have been used to identify venous aneurysms including duplex ultrasonography, venography, MRIs, CT scans, and even angiography.

At a histologic level, venous aneurysms have been found to have features similar to those of arterial aneurysms. There is evidence of increased metalloproteinases expression in venous aneurysms, and they have been considered part of the pathogenic process in the formation of arterial aneurysms. The histological and pathogenic similarities between arterial and venous aneurysms suggest that a common surgical approach is warranted. ⁷

Traditionally, in the majority of venous aneurysms, surgical excision has been common practice. ² However, successful treatment of an IVC aneurysm using a venous stent graft has been reported. ⁵ Due to the minimally invasive nature of stents, and known success in abdominal aortic aneurysms, an endovascular technique of a polytetrafluoroethylene-covered stent graft followed by excision was performed in our patient. ⁸

From our experience, we conclude that it is reasonable to approach venous aneurysms through a two-stage approach. A covered stent is deployed initially and surgical resection follows. This approach works particularly well for venous aneurysms involving the upper extremities, due to the complex anatomy, and high risk of thromboembolic events.