Subclavian Artery Thrombosis Treatment & Management

Early diagnosis and therapy of subclavian artery thrombosis are indicated to prevent disabling upper extremity ischemia and gangrene. As a temporizing measure, the use of catheter-directed thrombolytic therapy may be indicated for superimposed clot formation in an area of stenosis until definitive treatment of the obstruction can be undertaken.^[6]

Prolonged anticoagulation therapy for an obvious mechanical problem is not indicated. Anticoagulation may be considered as supplemental therapy after surgical intervention.

Surgery to correct subclavian artery thrombosis is the treatment of choice. Interventions include catheter-based procedures and formal operative procedures.

Angioplasty and stenting of stenotic and even occluded arteries have been undertaken successfully with adequate patency rates and minimal morbidity.^[7] These interventions are particularly appropriate for atherosclerotic arteries. A study to determine if stenting alone is superior proved inconclusive.^[8]

Subclavian artery occlusion secondary to thoracic outlet syndrome or muscular compression is treated by excision of the anatomical structure compressing the artery, whether muscle or bone.^[9] The artery may or may not require additional reconstruction, depending on the presence or absence of intimal damage.

The occluded artery may require a bypass procedure, depending on the location of the occlusion or the presence of a subclavian steal syndrome. The bypass options include subclavian-carotid, subclavian-subclavian, and axillary-axillary bypasses. Another possible bypass option is transposition of the subclavian artery to the ipsilateral carotid artery.

In any operative procedure for the problem, care must be taken to protect the thoracic duct from damage.

After the appropriate diagnostic studies have been performed to define the problem, operative preparation should be made. Administer preoperative prophylactic antibiotic therapy in the form of a first-generation cephalosporin. Perform appropriate preoperative medical screening to assess for evidence of other atherosclerotic disease such as coronary, carotid, or peripheral vascular occlusions.^[6]

For patients in whom the occlusion is secondary to atherosclerotic disease, perform a bypass of the area. For subclavian steal syndrome, a carotid-subclavian bypass using a ribbed synthetic tube graft is the procedure of choice (see image below).

Depending upon the location of the occlusion, subclavian-subclavian or axillary-axillary bypass can be undertaken using a ribbed synthetic conduit (see image below).

Because of the position of the graft and the necessity to, in some cases, cross bony structures, autologous vein conduits have limited patency.

For patients in whom thoracic outlet compression is the cause of the thrombosis, cervical rib resection via a supraclavicular incision appears to be adequate treatment. Resection of the midportion of the clavicle is sometimes needed for exposure. Undertake arterial resection because the intima of the vessel is damaged. Graft interposition may or may not be required. Redundancy of the normal adjacent artery may allow for end-to-end reconstruction. If a graft is required for arterial reconstruction, a large autogenous saphenous vein or expanded polytetrafluoroethylene or Dacron fabric grafts may be used. First rib resection may be indicated in these instances as well, depending on the size of the thoracic outlet.^[10]

In all procedures, care must be taken to identify and preserve the thoracic duct.

Check distal upper extremity pulses immediately after the operative procedure while the field is still sterile. Maintain careful observation for the development of muscular compartment syndromes, and perform compartment measurements if indicated. Concomitant fasciotomies may be indicated, depending on the length of ischemia suffered by the extremity prior to revascularization.

Evaluate postoperative effusions for the presence of chyle, which would be indicative of thoracic duct injury. Undertake prompt therapeutic measures if this complication occurs.

Perform postprocedural angiography at prescribed times after the operative intervention in order to assess patency of the graft or stent. One suggested timing sequence for the studies is at 1 month and 6 months, provided the patient remains asymptomatic. Noninvasive Doppler imaging can be used to assess distal flow to the extremity in the interim.

Potential complications of subclavian artery thrombosis secondary to atherosclerotic disease include distal embolization to the digits and neurological symptoms, including stroke secondary to a steal syndrome. Complications from operative interventions to address the arterial occlusion can include graft occlusion (acute and chronic), stent migration, stent occlusion, bleeding, and infection.

If the subclavian artery thrombosis is secondary to thoracic outlet problems, subclavian vein thrombosis can occur as well.^[11] Accompanying neurological symptoms resulting from brachial plexus compression can also be associated with the syndrome. Repair of the arterial thrombosis can again be complicated by graft thrombosis. Although rare, the possibility of postoperative bleeding should be reviewed with the patient before the operative intervention. Promptly address bleeding complications by reoperation in order to correct the problem.

Complications of the operative procedure can include injury to the thoracic duct. Pleural effusions should be promptly evaluated and appropriately treated.

The results from stenting procedures on the subclavian artery document an 87% patency rate after 3 years. Operative outcomes demonstrate about a 90% patency rate after 5 years.

The prognosis for the patient with atherosclerotic disease is directly dependent upon the severity of the disease and the willingness of the patient to modify lifestyle, including cessation of tobacco use and regulation of diet. If these modifications are made, the progression of the atherosclerotic process slows and the chance for recurrence of thrombosis falls.

For the patient whose occlusion is secondary to thoracic outlet problems, the prognosis after therapy is excellent.

The future therapy of subclavian artery thrombosis will most likely involve the use of endovascular stents.^{[12, 13]} As technology improves and a better understanding of restenosis issues is achieved, stenting of the lesions will be more commonplace.^{[14, 15]}

Careful assessment of patients with thoracic outlet syndrome will be required because of the complexity of this problem, the multiple structures involved, and the high-profile medicolegal issues that arise with treatment of these patients. Operative treatment of the arterial complications of the thoracic outlet syndrome should be performed. However, careful evaluation of the potentially associated venous and neurological pathologies should be undertaken prior to any operative therapy.