The Use of the Agatston Calcium Score in Predicting Carotid Plaque Vulnerability

Background: The use of the Agatston calcium scoring method has been described extensively in the coronary circulation, but to date, it has not been investigated in the extracranial carotid domain. We sought to evaluate this calcium scoring method in its ability to predict carotid plaque vulnerability. Methods: We retrospectively reviewed all computed tomography angiogram studies of the carotid arteries performed between March 2012 and March 2017 at a single institution. We identified 68 consecutive patients with 99 internal carotid arteries who met criteria for review. Total calcium was quantified by the Agatston scoring method using the OsiriX software. Stenosis severity was determined using North American Symptomatic Carotid Endarterectomy Trial criteria. The relation between Agatston score and degree of stenosis was evaluated using the Spearman's Rho coefficient (R). Results: Of 99 internal carotid arteries, 71 were asymptomatic and 28 were symptomatic. Baseline characteristics were comparable, with no significant difference in patient characteristics. There were significant differences in mean Agatston scores for asymptomatic versus symptomatic arteries (121.95 +/- 70.27 vs. 34.83 +/- 47.77, P = 0.0098, 50% -69% stenosis; 151.07 +/- 88.30 vs. 71.59 +/- 77.27, P = 0.0006, 70% -99% stenosis). In both asymptomatic and symptomatic groups, Agatston calcium score increased as severity of stenosis increased. Higher Agatston score is protective against symptoms ipsilateral to the carotid lesion. Conclusions: Agatston calcium score may predict carotid plaque vulnerability, with higher scores associated with lower likelihood of developing symptoms ipsilateral to the carotid lesion. This score may be useful in predicting clinical behavior of carotid plaques.