INTRODUCTION — Peripheral artery disease (PAD) of the upper extremities is common. It is most often asymptomatic but may cause exertional pains, ischemic pains, gangrene, or ulceration. Clinicians should focus on recognizing when upper extremity PAD merits treatment. Exertional pain is defined as a reproducible discomfort of a defined group of muscles induced by exercise and relieved with rest due to an imbalance between supply and demand of blood flow. The manifestations of upper extremity peripheral artery disease will be reviewed. Lower extremity peripheral artery disease is discussed in detail elsewhere. (See "Clinical features and diagnosis of lower extremity peripheral artery disease".)
UPPER EXTREMITY ARTERIAL ANATOMY — The subclavian arteries provide blood flow to the upper extremities. On the left, the subclavian artery originates directly from the aorta distal to the left common carotid artery. On the right, blood flows first through the innominate artery, which divides into the right common carotid artery and right subclavian artery. The anatomy of the aortic arch can vary (figure 1) and may include an anomalous origin of the subclavian arteries. Retroesophageal subclavian vessels may compress the esophagus causing dysphagia, but the vessel may also be compressed, leading to upper extremity ischemia. (See "Vascular rings and slings" and "Approach to the evaluation of dysphagia in adults", section on 'Cardiovascular abnormalities'.)
The vertebral arteries most often arise bilaterally as the first branch of the subclavian artery. In approximately 6 percent of patients, the vertebral artery, especially the left, may originate directly from the aortic arch [1]. The subclavian artery passes over the first rib posterior to the anterior scalene muscle (figure 2) and becomes the axillary artery at the lateral margin of the first rib. The axillary artery becomes the brachial artery (figure 3) at the lower margin of the teres major muscle. The brachial artery passes between the biceps and triceps muscles accompanied by the ulnar and median nerves adjacent to the humerus and supplies the soft tissues of the arm. In the antecubital fossa, the brachial artery divides (figure 4) into the radial, interosseus, and ulnar arteries to supply soft tissues of the forearm. Distally at the wrist, the ulnar artery and radial artery supply the hand (figure 5).
The extensive collateral circulation around the shoulder compensates well for stenoses and occlusions in the innominate, subclavian, and axillary arteries (figure 6). When the proximal subclavian artery is occluded, blood flow is maintained to the arm via connections between the superior and inferior thyroid arteries; vertebral arteries, intercostals, superior epigastric and internal thoracic arteries; profunda cervicis and descending branch of the occipital artery; scapular branches of the thyrocervical trunk and the branches of the axillary artery; and the thoracic branches of the axillary artery with the aortic intercostals [2].
PRESENTATION — Most patients with upper extremity peripheral artery disease are asymptomatic and are detected only by the finding of asymmetric arm blood pressures. If a difference is identified, we repeat the blood pressure measurement in both arms to confirm the finding. (See 'Diagnosis' below.)
Patients who develop dizziness, or even syncope, during arm exertion may have retrograde blood flow in the vertebral artery to supply the demand of the arm skeletal muscle in the setting of reduced subclavian artery blood flow due to a proximal occlusion. This is referred to as subclavian steal syndrome. The clinical manifestations and treatment of subclavian steal syndrome are discussed in detail elsewhere. (See "Subclavian steal syndrome", section on 'Definition and physiology'.)
Less commonly, stenosis or occlusion of the proximal upper extremity arteries can lead to symptoms of arm pain with exertion, evidence of thromboembolism, acute limb ischemia, or chronic ischemic symptoms (ischemic rest pain, digit ulceration).
Patients who present with a differential blood pressure in the setting of acute chest pain, however, should be evaluated for an acute aortic syndrome (eg, aortic dissection) or, if the patient has had a prior cardiac bypass, coronary-subclavian steal syndrome. (See "Subclavian steal syndrome", section on 'Coronary-subclavian steal'.)
DIAGNOSIS — Two findings should suggest the presence of asymptomatic upper extremity peripheral artery disease (PAD): the presence of lower extremity PAD or an arm blood pressure differential of 15 mmHg or more. An analysis of several large patient cohorts found subclavian artery stenosis in 6.0 percent of men and 9.7 percent of women with lower extremity PAD. By comparison, less than 2 percent of individuals without PAD had subclavian stenosis [3]. In another study of a small cohort, approximately 40 percent of cardiac surgery patients with a systolic pressure differential in the arm of 15 mmHg or more had subclavian stenosis, while only 10 percent of those without a gradient had subclavian artery stenosis [4].
The blood pressure differential in the upper extremity can be confirmed in the vascular laboratory and the specific site and severity of stenosis or occlusion identified with segmental arm pressures and duplex ultrasound. With duplex, the ultrasound waveform distal to a proximal stenosis will demonstrate a blunted waveform. If the vessel is occluded, no blood flow will be seen, but collateral vessels may be apparent. (See "Noninvasive diagnosis of upper and lower extremity arterial disease", section on 'Upper extremity segmental pressures' and "Noninvasive diagnosis of upper and lower extremity arterial disease".)
If the patient is symptomatic and the diagnosis remains in question, computed tomographic (CT) angiography, magnetic resonance (MR) angiography, or digital subtraction arteriography (image 1) may be indicated to establish the diagnosis.
Atherosclerosis is the most common cause of ischemic upper extremity disease (table 1), but other causes of upper extremity ischemia include large artery diseases such as arterial injury, arterial dissection, thrombosed aneurysm, atheroembolism, thromboembolism, fibrodysplasia, arteritis (eg, Takayasu disease, giant cell arteritis), and repetitive arterial injury (thoracic outlet syndrome, crutch injury) and small vessel diseases such as vasculitis; occupational injury; sequelae of radiation therapy; and disorders related to vasoconstriction [5,6].
MANAGEMENT — Upper extremity peripheral artery disease is often associated with atherosclerosis involving other large vessels, particularly the carotid, coronary, and lower extremity arteries. One study using baseline and longitudinal data for three cohorts that included 1778 participants found that subclavian stenosis predicted total and cardiovascular disease mortality independent of both cardiovascular risk factors and existent cardiovascular disease at baseline [7]. In another study, the prevalence of subclavian artery stenosis in patients undergoing myocardial revascularization was reported in the 0.5 to 1.0 percent range [8].
Thus, the detection of upper extremity peripheral artery disease identifies patients at increased risk for stroke and cardiovascular disease and who may benefit from secondary prevention measures such as the following:
●Control of hypertension
●Lipid modification
●Glycemic control in diabetes
●Smoking cessation
●Therapeutic lifestyle changes
●Antithrombotic therapy
Risk factor modification and secondary prevention of cardiovascular disease and stroke are discussed in detail separately. (See "Prevention of cardiovascular disease events in those with established disease (secondary prevention) or at very high risk" and "Management of claudication due to peripheral artery disease" and "Overview of secondary prevention of ischemic stroke" and "Overview of lower extremity peripheral artery disease", section on 'Risk factor modification'.)
Patients who do not have symptoms do not require intervention. Options for the treatment of symptomatic subclavian stenosis or occlusion include surgical revascularization (eg, carotid-subclavian bypass, subclavian transposition) and percutaneous transluminal angioplasty and stenting. Percutaneous catheter-based treatment is less invasive and associated with lower complication rates and shorter hospitalization. The treatment of symptoms of subclavian steal syndrome is discussed in detail elsewhere. (See "Subclavian steal syndrome", section on 'Management'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Occlusive carotid, aortic, renal, mesenteric, and peripheral atherosclerotic disease".)
SUMMARY AND RECOMMENDATIONS
●Although symptoms due to peripheral artery disease (PAD) are more common in the lower extremities, upper-extremity exercise-induced pain, pain at rest, and even tissue loss may also manifest in the upper extremities. (See 'Introduction' above.)
●The subclavian arteries provide blood flow to the upper extremities. On the left, the subclavian artery originates directly from the aorta distal to the left common carotid artery. On the right, blood flows first through the innominate artery, which divides into the right common carotid artery and right subclavian artery. The collateral circulation around the shoulder is usually sufficient such that flow around a focal area of stenosis in the subclavian artery is well tolerated. (See 'Upper extremity arterial anatomy' above.)
●Most patients with upper extremity peripheral artery disease have few to no symptoms and present only with a difference in the systolic blood pressure between one arm and the other. However, stenosis or occlusion of the upper extremity arteries can be associated with symptoms of arm pain with exertion, evidence of distal thromboembolism, acute limb ischemia, or chronic ischemic symptoms (ischemic rest pain, digit ulceration). Patients with abnormal retrograde vertebral artery blood flow during part of, or all of, the cardiac cycle who experience arm claudication, dizziness, or syncope during arm exertion have subclavian steal syndrome. (See 'Presentation' above.)
●Atherosclerosis is the most common cause of ischemic upper extremity disease (table 1), but other causes of upper extremity ischemia include small artery diseases (eg, vasculitis, disorders related to vasoconstriction) and large artery diseases such as arterial injury, arterial dissection, thrombosed aneurysm, atheroembolism, thromboembolism, fibrodysplasia, arteritis (eg, Takayasu disease, giant cell arteritis), and repetitive arterial injury. (See 'Diagnosis' above.)
●Upper extremity peripheral artery disease is often associated with atherosclerosis involving other large vessels, particularly the carotid, coronary, and lower extremity arteries. Thus, similar to the identification of lower extremity peripheral artery disease, the detection of upper extremity peripheral artery disease identifies patients at increased risk for stroke and cardiovascular disease and who may benefit from secondary prevention measures such as control of smoking cessation, control of hypertension, lipid modification, control of blood sugar, and antithrombotic therapy. (See 'Management' above.)
ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Emile R Mohler, III, MD, now deceased, who contributed to an earlier version of this topic review. UpToDate also wishes to acknowledge Dr. Mohler's work as our Section Editor for Vascular Medicine.
