Subclavian steal syndrome

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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. [1]
  • 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

Clinical Features

Symptoms in Upper Extremity

  • Pain
  • Fatigue
  • Coolness
  • Paresthesias
  • Numbness

Neurologic Symptoms

Differential Diagnosis [2]

Shoulder and Upper Arm Diagnoses

Traumatic/Acute:

Nontraumatic/Chronic:

Refered pain & non-orthopedic causes:

Evaluation

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

Diagnostic Tests [3]

  • 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

References

  1. Potter BJ, Pinto DS. Subclavian steal syndrome. Circulation. 2014; 129(22):2320-3.
  2. De Lorenzo R. Syncope. In: Marx J, ed. Rosen's Emergency Medicine. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014: 135-141.
  3. Berguer R, Higgins R, Nelson R. Noninvasive diagnosis of reversal of vertebral-artery blood flow. NEJM. 1980; 302(24):1349-51

Authors:

Neil Young