In this study it expLains very clearly that The type III arch configuration has been inconsistently reported as a stroke risk factor during carotid artery stenting. However, at least three different methods for the definition of type III arch can be identified in the literature, related to the level of the origin of the innominate artery (IA). According to Casserly’s definition, a type III arch presents with an origin of the IA below the horizontal plane of the inner curvature. According to Madhwal’s definition, a type III arch has a distance greater than twice the diameter of the left common carotid artery between the highest point of the arch and the origin of the IA. According to MacDonald’s definition, a type III arch presents with a distance of ≥2 cm between the highest point of the arch and the origin of the IA. Our aim was to assess the level of concordance between these different methods.

Anonymized thoracic computed tomography scans of 100 healthy patients were reviewed. Two of us independently stratified the selected cases as a type I to III arch, according to the three considered definitions. The interobserver level of concordance for each type III arch classification and level of concordance among the three definitions were assessed.

Reference link- https://www.jvascsurg.org/article/S0741-5214(20)32122-4/fulltext