Differential diagnosis, decision-making, and pathways of care for ATOS

The diagnosis of arterial thoracic outlet syndrome (ATOS) is made when the patient's primary symptoms are arterial in nature even though the patient may also have neurogenic or venous symptoms. The neurovascular bundle in the thoracic outlet is compressed when the arm and shoulder are placed in certain positions in many patients without symptoms. In some, however, repeated injury may occur and produce arterial wall injury leading to endothelial ulceration, clot formation, post-stenotic aneurysmal dilatation, digital embolization, forearm vessel occlusion, and/or proximal arterial occlusion. This process is often silent and progressive. Subclavian-axillary artery lesions may be produced by either abnormal bony structures or normal structures that become abnormal with certain arm positioning.