Subclavian steal: a harmless haemodynamic phenomenon?

Area of Science:

• Vascular Surgery
• Neurology
• Diagnostic Imaging

Background:

• Neck bruits are common clinical findings, often associated with extracranial atherosclerosis.
• Subclavian steal syndrome (SSS) can occur secondary to subclavian artery stenosis.
• The clinical significance of asymptomatic subclavian steal requires further investigation.

Purpose of the Study:

• To prospectively evaluate the incidence and clinical significance of subclavian steal in patients with asymptomatic neck bruits.
• To assess the utility of continuous-wave carotid Doppler ultrasonography in detecting subclavian steal.

Main Methods:

• Prospective follow-up of 500 patients with asymptomatic neck bruits for up to 4 years.
• Standardized clinical assessments and continuous-wave carotid Doppler ultrasonography were employed.
• Subclavian steal was assessed using Doppler ultrasonography, including a standardized steal test.

Main Results:

• 9% of patients (45/500) had severe subclavian stenosis.
• 64% of these (32/45) demonstrated a positive subclavian steal test, predominantly left-sided (27/32).
• No patients experienced symptoms during the steal test or stroke during the follow-up period.

Conclusions:

• Severe subclavian stenosis and positive subclavian steal tests are relatively common in patients with asymptomatic neck bruits.
• These findings are generally asymptomatic and do not appear to increase the risk of stroke.
• Continuous-wave carotid Doppler ultrasonography is effective in identifying subclavian steal in this population.