What are the causes of thoracic outlet syndrome (TOS) and venous pooling with contrast?

From the Guidelines

Contrast venography is the most appropriate imaging technique for evaluating venous pooling in thoracic outlet syndrome (TOS), as it allows for the assessment of venous compression and pooling in the thoracic outlet area, particularly in patients with suspected venous TOS (vTOS) 1. When evaluating TOS, it is essential to consider the different anatomic spaces that can be implicated, including the costoclavicular triangle, interscalene triangle, and pectoralis minor space, as narrowing of these spaces can result in varying degrees of venous, arterial, or neurological symptoms 1.

• The costoclavicular triangle is the most common site of compression, leading to venous symptoms, and contrast venography can help identify venous pooling in this area.
• The procedure involves injecting contrast material into the veins and observing its flow through the thoracic outlet area, typically with the patient's arms in various positions to demonstrate positional compression of the subclavian vein.
• The contrast medium, usually an iodinated agent, is injected into the affected arm's peripheral vein, and venous pooling is visible as contrast stagnation proximal to the thoracic outlet.
• This finding helps differentiate TOS from other conditions causing similar symptoms, and the procedure is particularly valuable for diagnosing venous TOS when clinical examination and non-contrast studies are inconclusive 1. In terms of patient preparation and safety, patients should inform their provider about any contrast allergies beforehand and maintain good hydration after the procedure to help eliminate the contrast from their system.
• The procedure typically takes 30-60 minutes and may cause temporary discomfort at the injection site.
• It is crucial to consult with a radiologist to optimize the study for the prevailing clinical symptom, especially in the postoperative setting, where a new symptom may indicate a complication 1.

From the Research

Thoracic Outlet Syndrome (TOS) and Venous Pooling with Contrast

• TOS is a rare condition caused by neurovascular compression at the thoracic outlet, presenting with arm pain and swelling, arm fatigue, paresthesias, weakness, and discoloration of the hand 2.
• Venous TOS is a spectrum of disease caused by external compression of the subclavian vein as it passes through the costoclavicular space, which can lead to venous thrombosis 3.
• The use of contrast-enhanced venography is a component of the imaging evaluation of clinically suspected venous TOS, and can help identify angiographic evidence of venous TOS 4.
• Catheter-directed therapies, such as thrombolysis or angioplasty, can be used to treat venous TOS, and can be combined with surgical decompression for effective management 4, 3.
• Postdecompression venoplasty appears to be highly effective in managing patients with venous TOS, with a low rate of symptom recurrence 4.
• The diagnosis of TOS can be established through history, physical examination maneuvers, and imaging, and treatment options include nonsurgical and surgical approaches, such as brachial plexus decompression, neurolysis, and scalenotomy with or without first rib resection 2, 5.
• Surgical management of TOS can provide excellent relief of symptoms, with low morbidity, and can be offered as an early option for patients with TOS 6.