Subclavian steal syndrome

Background

• Stenosis of the subclavian artery, proximal to the origin of the vertebral vessel, results in decreased perfusion pressure to the distal subclavian artery, leading to retrograde flow in the ipsilateral vertebral artery with exercise of the ipsilateral arm. In short, the arm steals blood flow from the vertebrobasilar system resulting in neurologic and upper extremity symptoms due to arterial insufficiency.
• Increased incidence of left-sided subclavian stenosis
• The presence of collateral blood supply is the main determinant of which patients develop neurologic symptoms

Subclavian Steal Diagram

Etiology

• Atherosclerosis
• Thoracic outlet obstruction
• Congenital anomalies
• Takayasu arteritis

Clinical Features

Symptoms in Upper Extremity

• Pain
• Fatigue
• Coolness
• Paresthesias
• Numbness

Neurologic Symptoms

• Dizziness, Lightheadedness
• Vertigo
• Syncope

Physical Exam Findings

• Supraclavicular bruit, thrill
• Systolic BP in ipsilateral brachial artery is reduced compared to opposite side
• Ipsilateral radial pulse with decreased amplitude and delayed arrival

Differential Diagnosis

• Thoracic outlet syndrome
• Vertebrobasilar insufficiency
• Syncope
• Vertigo

Shoulder and Upper Arm Diagnoses

Traumatic/Acute:

• Shoulder Dislocation
  • Anterior shoulder dislocation
  • Posterior shoulder dislocation
  • Inferior shoulder dislocation
• Clavicle fracture
• Humerus fracture
• Scapula fracture
• Acromioclavicular joint injury
• Glenohumeral instability
• Rotator cuff tear
• Biceps tendon rupture
• Triceps tendon rupture
• Septic joint

Nontraumatic/Chronic:

• Rotator cuff tear
• Impingement syndrome
• Calcific tendinitis
• Adhesive capsulitis
• Biceps tendinitis
• Subacromial bursitis
• Cervical radiculopathy

Refered pain & non-orthopedic causes:

• Referred pain from
  • Neck
  • Diaphragm (e.g. gallbladder disease)
• Brachial plexus injury
  • Rucksack paralysis
• Axillary artery thrombosis
• Thoracic outlet syndrome
• Subclavian steal syndrome
• Pancoast tumor
• Myocardial infarction
• Pneumonia
• Pulmonary embolism

Evaluation

Diagnostic Tests

• Routine testing for atherosclerosis: Lipid panel, Glucose
• Doppler ultrasound
• CXR, ECG
• CTA, MRA
• Angiography

Management

Medical Management

1. Treat atherosclerosis
2. Antiplatelet therapy
3. Anticoagulant therapy

Surgical Management

Indicated for symptomatic patients

1. Angioplasty with endovascular stenting
2. CEA (in patients with associated carotid stenosis) by increasing collateral blood flow
3. Surgical bypass

Disposition

• If symptomatic, admit with consults to Vascular Surgery, Neurology
• If incidental finding, consider close outpatient follow-up