Subclavian artery disease


Underecognized peripheral vascular disease.

It is present in approximate 2% of the general population.

Majority of patients are asymptomatic due to slow disease progression and the development of collateral circulation.

Associated with smoking, hypertension, low levels of HDL, and lower extremity peripheral disease.

Brachiocephalic arterial disease prevalence is 42% inpatients with peripheral artery disease.

54% of patients with peripheral artery disease have greater than 30% stenosis of the left subclavian artery.

Most frequently caused by atherosclerosis, but other etiologies include congenital malformations, fibromuscular dysplasia, Neorofibromatosis, inflammation, radiation exposure, and mechanical causes.

The left subclavian artery is more likely to be affected than the right.

Atherosclerosis of the brachiocephalic vessels is uncommon in comparison to the prevalence of disease in the extracranial carotid arteries.

The left subclavian artery originates as the third branch from the transverse region of the aorta, following the brachiocephalic trunk and the left common carotid artery.

The subclavian artery gives rise to the vertebral artery, the internal mammary artery and the thyrocervical trunk, prior to terminating as the axillary artery.

The subclavian artery supplies blood to structures in the chest and brain, and these branches serve as collaterals for retrograde filling of the subclavian artery in cases of critical stenosis or occlusion.

Stenosis of the brachiocephalic trunk is infrequent in comparison to the left subclavian artery and can produce symptoms involving either the upper extremity or the right carotid distribution.

Proximal lesions of the subclavian artery are mostly asymptomatic.

Proximal lesions of the subclavian artery can be found by asymmetric pulses or blood pressures between both upper extremities.

No treatment is usually necessary if no symptoms are present.

Patients with symptoms, however, are a small portion of patients with this disease that may eventually require treatment.

Subclavian steal syndrome, upper extremity claudication and coronary steal syndrome are the three most common presentations of symptomatic patients with proximal occlusive disease.

Thromboembolic complications can occur in a small number of patients as painful digits with skin color changes.

Subclavian steal syndrome is a compromised vertebrobasilar circulation, secondary to retrograde flow to the arm from the contralateral vertebral artery resulting in the stealing of blood from the posterior cerebral circulation.

Upper extremity claudication, especially with repetitive movement, can occur.

Angina pectoris, secondary to coronary steal syndrome, is a significant presenting symptom.

Subclavian steal syndrome also occurs when the left internal mammary artery has been used for coronary revascularization, and there is also a hemodynamically significant lesion in the proximal left subclavian artery.

Reversal of blood flow can occur in both the vertebral and internal mammary artery, or can be isolated to either vessel.

The incidence of coronary steal syndrome has been estimated at less than 0.5%, and presents with symptoms of cardiac ischemia after excessive use of the left upper extremity.

Initial evaluation for subclavian artery occlusive disease is the measurement of bilateral brachial artery blood pressures.

A significant difference between the two extremities is considered to be 20 mmHg and above.

Arterial duplex as a second line of test can identify a significantly elevated velocity in the proximal subclavian artery (i.e., >300 cm/s), as well as a change in its waveform from the normal triphasic appearance to a more biphasic or monophasic waveform.

With subclavian steal from the vertebral artery, there is a graded system showing a progressive change in the ipsilateral vertebral artery waveform.

Grade I lesions demonstrate antegrade flow with a diminished peak systolic velocity.

Grade II lesions show retrograde flow during systole and antegrade flow during diastole.

Grade III lesions have flow that is completely retrograde, regardless of cardiac contractility, a compensatory mechanism to increase flow to the affected extremity.

Imaging of the great vessels is performed if treatment is contemplated and preoperative viewing is required..

Surgical transthoracic management have patencies of 94 and 98% at 5 years, with the 10-year patency still quite good at 88 and 96%, respectively.

Surgical transthoracic management perioperative mortality rates are found to be 5 and 6%, and a stroke rate of only 3.4%.

Cervical reconstruction has shown a similar success rate with less perioperative morbidity.

Cervical reconstruction has become the pref2242ed surgical approach in high-risk patients with isolated single-vessel disease.

Endovascular techniques of treating subclavian artery occlusive disease have brought better outcomes and higher success rates for both angioplasty and stenting.

In the past decade, there has been a shift from angioplasty alone, to primary stenting of the artery.

Endovascular studios have suggested that ostial lesions, which are frequently aortic lesions, that are unfavorable to angioplasty alone.

Stenting of subclavian arteries has an excellent success rate, including a lower chance of intimal injury, vessel thrombosis, and distal embolization, as well as a higher procedural technical success rate secondary to improved response to recoil.

Access to the subclavian artery can be achieved from either a brachial or femoral approach.

Complications following endovascular treatment can either local or remote.

Complications include both access and neurologic complications.

Vascular access complications may require operative intervention.

Vascular access complications include hematomas, thromboses and/or brachial artery dissections.

Vascular access complications rate can range from 2 to 9%.

Brachial artery complications may be up to five times as common as femoral approaches.

Neurologic complications involve both arterial dissections and stroke.

Stoke complication can occur due to aortic arch or embolization/dissection of the vertebral artery.

Stoke complication occurs at a rate of 2.2%, secondary to the reversal of flow in the vertebral artery.

Other complications that can occur include nerve injury during access, stent infections and subclavian artery rupture.

Median nerve injury can occur during brachial artery access.

Subclavian angioplasty, the endoluminal therapy, for subclavian disease is effective and safe; however, open surgery still carries a better long-term durability and should be the pref2242ed approach in low-risk patients.

Subclavian artery disease occurs in approximately 2% of patients undergoing coronary revascularization and up to 15% of selected cohorts, can be treated by endovascular techniques with great perioperative success and acceptable long-term patency.

Patients who have endovascular technical failures or subsequent loss of patency, should be considered for surgical revascularization.

Asymptomatic lesions have a benign natural history.

For symptomatic lesions, endovascular management has become first line of treatment in most cases.

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