Analyzing the Potential Impact of the Proposed IAC Recommendations for Carotid Duplex Surveillance of Carotid Stenosis

Abstract

We retrospectively evaluated the application of proposed carotid artery stenosis surveillance guidelines to historic patient populations within our vascular lab database. We specifically examined the rate of complex plaque morphology present in the newly excluded patient population. We have identified a significant patient population with distinct plaque morphologies which are suggestive of future clinical progression that would be excluded from follow-up imaging. We performed a single-center retrospective study examining all carotid artery studies within our IAC certified lab from January 1, 2020, to December 31, 2020, that were identified as having moderate carotid artery stenosis (50%-69%) based off our current protocols using a peak systolic velocity (PSV) of 125 to 230 cm/s and internal carotid artery/common carotid artery ratios ranging from 2 to 4. These studies were then compared to the new recommendations of PSV of >180 cm/s or a ratio of >2.0. We excluded the studies that were moderate stenosis per the new guidelines and examined the studies that would be excluded based on the same guidelines for the presence of calcified or ulcerative plaques. Of the 1076 examinations performed that identified moderate carotid artery stenosis based upon the old criteria, only 782 of these studies demonstrated similar hemodynamically significant stenosis. We examined the remaining 294 studies and found 205 (69.7%) of those studies possessed imaging characteristics concerning for complex plaques (Table, Figure). The increase of PSV to 180 would recategorize 19% of our patients examined over 1 year to <50% stenosis and based upon current recommendations, would be lost to follow-up surveillance for disease progression. Our data suggest currently recommended guidelines would exclude a significant number of patients from routine surveillance that demonstrate plaques that could pose a risk for clinical progression. Our data suggest that more prospective data should be obtained, particularly that pertaining to risk factors that would place the patient at risk for plaque progression, prior to adopting the newly recommended surveillance guidelines.TablePatient dataModerate stenosis per old criteria1076Moderate stenosis per proposed changes782Patients who would be excluded294Patients with concerning plaque morphology205 Open table in a new tab