Diagnosis
Extracranial Carotid Artery
➤ After carotid endarterectomy (CEA) or carotid artery stenting (CAS), the
Society for Vascular Surgery (SVS) recommends surveillance with DUS
at baseline and every 6 months for 2 years and annually thereafter until
stable (i.e., until no restenosis or in-stent restenosis [ISR] is observed
in two consecutive annual scans). The first or baseline DUS should occur
soon after the procedure, preferably within 3 months, with the goal of
establishing a post-treatment baseline. Considering the small risk of
delayed restenosis or ISR, some interval of regular surveillance (e.g., every
2 years) should be maintained for the life of the patient. (1-B)
➤ For patients undergoing CAS with diabetes, aggressive patterns of
ISR (type IV), prior treatment for ISR, prior cervical radiation or heavy
calcification, in addition to the baseline DUS the SVS recommends
surveillance with DUS every 6 months until a stable clinical pattern is
established and annually thereafter. (1-B)
➤ The SVS recommends that DUS after CAS include at least the following
assessments (1-C):
• Doppler measurement of peak systolic velocity (PSV) and end-diastolic velocity (EDV)
in the native common carotid artery (CCA); in the proximal, mid, and distal stent; and
in the distal native internal carotid artery (ICA). Modified threshold velocity criteria
should be used to interpret the significance of these velocity measurements after CAS.
• B-mode imaging should be used to supplement and to enhance the accuracy of velocity
criteria to estimate the severity of luminal narrowing.
Figure 1. Morphologic Patterns of ISR Based on B-mode Imaging
Type I, focal ≤10 mm, end-stent lesions; Type II, focal ≤10 mm, intrastent lesions; Type III,
diffuse >10 mm, intrastent lesions; Type IV, diffuse >10 mm, proliferative lesions extending
outside the stent; and Type V, total occlusion.