The clinical implications of adopting new criteria for the grading of internal carotid artery stenosis.

Abstract

A patient's eligibility for carotid endarterectomy (CEA) is determined primarily by the degree of carotid stenosis detected on duplex ultrasound. The Australasian Society for Ultrasound in Medicine (ASUM) criteria are widely used to grade carotid stenoses in many practices throughout Australasia. We sought to investigate the potential impact on the grading of carotid artery stenosis if practitioners switched from the ASUM criteria to the United Kingdom's joint recommendation (UKJR) criteria by reviewing 100 patients with a haemodynamically significant carotid artery stenosis. We found agreement between the criteria in 100% of cases for stenoses <50%, in 80% of cases for stenoses 50-69%, in 89% of cases for stenoses ≥70% and in 100% of cases for stenoses ≥80%. While there was variation in grading of stenoses in 16% of cases, reclassification resulted in no change in the number of patients eligible for CEA. The UKJR guideline enabled more precise categorisation of haemodynamically significant stenosis into deciles. Because the UKJR guideline is more comprehensive, we believe that adopting this guideline would enable the ultrasound practitioner to grade carotid stenoses more precisely, better understand the nuances of carotid duplex imaging and more successfully navigate and interpret complex carotid examinations, without impacting the number of patients eligible for CEA.