Thrombosis of the axillary vein or subclavian vein is a relatively uncommon event, accounting for less than 5% of all cases of DVT. Only 12% result in pulmonary thromboembolism, but local symptoms of upper extremity thrombosis can cause significant disability.
There are two major etiologies. Primary axillary-subclavian thrombosis occurs as a result of intermittent transient obstruction of the vein in the costoclavicular space during repetitive or strenuous activities involving the upper extremity. This condition was first described in independent reports by Paget. During strenuous repetitive movements of the upper extremity, the subclavian vein is compressed between the first rib and the clavicle—with underlying subclavius muscle and fibrous costocoracoid ligament—anteriorly. Subclavian vein thrombosis can also occur in patients with hypercoagulable states such as antiphospholipid antibody syndrome. Secondary subclavian vein thrombosis results from venous injury by indwelling central venous catheters, external trauma, or pacemaker wires.
Symptoms and Signs of axillary-subclavian vein thrombosis
Primary axillary-subclavian vein thrombosis usually occurs in healthy young athletes and people who perform heavy manual labor. Men outnumber women 4:1. Most often patients give a history of repetitive arm activity, but sometimes a single strenuous exercise, such as wrestling or weight lifting, can precipitate thrombosis. Most patients present with an aching pain most severe in the axilla, accompanied by edema and cyanosis of the upper extremity. Significant superficial venous distention is usually apparent in the arm, forearm, shoulder, and anterior chest wall. Symptoms may abate somewhat with the arm elevated.
Paget-Schroetter syndrome may also be accompanied by symptoms of thoracic outlet syndrome: tingling, numbness, and pain in the hand and anterior chest wall caused by compression of the brachial plexus between hypertrophied or scalene muscles. Some patients may have a positive Adson test, signifying impingement of the subclavian artery. This test is positive if diminishment of the radial pulse is noted on abducting and externally rotating the arm while turning the head away from the arm examined. Thoracic outlet syndrome involving the arterial circulation is manifested by effort fatigue of the arm, coolness, and digital embolization.
Upper extremity venous duplex ultrasound is a good screening modality for patients with suspected axillary-subclavian vein thrombosis. If this study is positive, upper extremity venography and thrombolysis should be considered. It is important that the patient undergo positional venography, abducting the arm 120 degrees to confirm extrinsic compression of the subclavian vein at the thoracic outlet. Venous compromise is further evidenced by prominent collateral veins.
Chest x-ray should be obtained on all patients to exclude the presence of cervical rib, which can also cause compression of the subclavian vein.
Treatment of axillary-subclavian vein thrombosis
Any indwelling central venous lines or pacemaker wires in the thrombosed vein should be removed if possible. Arm elevation, pain control, and intravenous fluid resuscitation should be instituted.
Distinguishing these types of thoracic outlet syndrome is important in selecting the appropriate mode of therapy. A new standard of care is emerging. Selective catheterization with thrombolytic infusion is performed at diagnosis. Lytic agent is infused over 12–24 hours through a multi-sideholed catheter centered in the thrombosed vein. Positional venography is repeated after lysis of the clot is achieved. If short-segment stenoses resulting from venous catheterization are identified, these can be corrected by angioplasty. Compression of the vein with the appearance of large venous collaterals when the arm is abducted suggests venous thoracic outlet syndrome, involving the venous circulation, which is best treated with early surgery. A 35–65% risk of rethrombosis and chronic venous stasis is expected without surgery. Delaying surgery to allow endothelial remodeling while the patient receives anticoagulation has not been proved to enhance outcome.
Because the etiology is compression of the vein between the first rib and the clavicle, surgery consists of anterior scalenectomy, first rib resection, venolysis (release of the vein from constricting scar). This operative plan may be modified if there is residual thrombus in the vein (thrombectomy with primary closure or patch angioplasty, interposition graft, internal jugular turndown, or jugular-subclavian bypass), or concomitant neurogenic thoracic outlet syndrome (scalenectomy with neurolysis) or arterial thoracic outlet syndrome (scalenectomy with resection of subclavian aneurysm). Positional venography is performed postoperatively, with angioplasty and stenting reserved for tight residual venous stenoses. Warfarin is continued for 1–3 months, and aspirin is then continued indefinitely afterward.
It is the general practice at our institution to evaluate patients for hypercoagulable states. The most common of which are mutations in coagulation factor V and antithrombin III. Because of a 40–60% rate of recurrent thrombosis, these patients are maintained indefinitely on warfarin.
The prognosis after axillary-subclavian vein thrombosis is dependent upon the cause of the condition. Most patients experience fairly rapid resolution of their initial presenting symptoms. For patients with secondary forms of this disease, the outcome is dependent upon resolution of the underlying condition. For patients with Paget-Schroetter syndrome who undergo thoracic outlet decompression, excellent outcomes in terms of continued venous patency and avoidance of symptoms of chronic venous insufficiency can be expected. In contrast, chronic axillary-subclavian vein thrombosis with symptoms persisting for over 3 months does not often respond to thrombolysis, mechanical thrombolysis, or prolonged anticoagulation and may cause significant long-term disability.