Is an ultrasound of the carotids recommended 1 year after carotid stent placement?

Ultrasound Surveillance After Carotid Stenting at 1 Year

Yes, ultrasound surveillance at 1 year after carotid stent placement is recommended and rated as appropriate by major cardiovascular societies. 1

Surveillance Schedule After Carotid Artery Stenting

The American College of Cardiology and American Heart Association provide clear guidance on post-stenting surveillance intervals:

First Year Protocol

• Initial scan: Within 30 days (1 month) post-procedure 2
• 6-month scan: Appropriate for all patients 1
• 9-12 month scan: Rated as appropriate surveillance timing 1

After First Year

• Annual surveillance (every 12 months) is recommended if the baseline study shows abnormalities 1
• If the baseline study is normal, surveillance every 24 months or greater may be appropriate 1

Clinical Rationale for 1-Year Surveillance

Restenosis after carotid stenting occurs in 5-11% of patients, making surveillance critical for detecting clinically significant stenosis before symptoms develop 1:

• In the SPACE trial, 10.7% of CAS patients developed ≥70% restenosis at 1 year 1
• In CAVATAS, 14% of CAS patients had 70-99% stenosis detected at 1 year 1
• Most restenosis within the first 18 months is due to intimal hyperplasia and is typically asymptomatic 1

What the 1-Year Ultrasound Should Assess

The duplex ultrasound should measure:

• Peak systolic velocity (PSV) in the stented internal carotid artery 2
• End-diastolic velocity 3
• PSV ratio (stented ICA/common carotid artery) 3

Interpretation Criteria for Stented Arteries

Note that standard velocity criteria for non-stented arteries overestimate stenosis severity in stented vessels 4:

• Normal stented artery: PSV <155 cm/s 4
• ≥30% in-stent restenosis: PSV >155 cm/s 4
• High-grade stenosis (≥70%): PSV >300 cm/s, end-diastolic velocity >125 cm/s, ICA/CCA ratio >4 3

Management Based on 1-Year Findings

If Normal or Mild Stenosis

• Continue annual surveillance 1, 2
• Maintain aggressive medical therapy (antiplatelet agents, high-intensity statins, blood pressure control) 2

If Moderate Stenosis (50-69%)

• Increase surveillance frequency to every 6 months 1
• Continue optimal medical management 2

If Severe Stenosis (≥70%)

• Consider additional imaging (CT angiography or catheter angiography) for confirmation 2
• Symptomatic patients with ≥50% restenosis: Consider repeat revascularization 1
• Asymptomatic patients with ≥80% restenosis: May consider repeat revascularization 1

Important Caveats

Stent artifacts can complicate ultrasound interpretation, and velocity measurements may be affected by the stent itself 1. When ultrasound findings are equivocal or discordant with clinical presentation, confirmatory imaging with CT angiography or catheter angiography should be obtained 2.

Most in-stent restenosis is asymptomatic and benign, rarely requiring reintervention 1, 5. However, surveillance allows for early detection and intervention before progression to symptomatic or preocclusive disease 3.

The surveillance should be performed in a certified vascular laboratory by qualified technologists to ensure accurate and reproducible measurements 6.