Lesion- and vessel-specific coronary artery calcium scores are superior to whole-heart Agatston and volume scores in the diagnosis of obstructive coronary artery disease.

BACKGROUND: The whole-heart coronary artery calcium (CAC) score has poor predictive value for obstructive coronary artery disease (CAD). We hypothesized that vessel- and lesion-specific CAC scores are more accurate.
OBJECTIVES: To evaluate the usefulness of vessel- and lesion-specific CAC in predicting obstructive CAD and to assess the incremental value added by the vessel- and lesion-specific CAC to the conventional whole-heart CAC approach.
METHODS: Ninety-one patients with CAC scores and invasive angiography (XRA) data were enrolled. Besides whole-heart CAC, Agatston score (AgSc) and volume score (VolSc) were measured individually for each lesion in the 4 major epicardial coronary arteries. Maximum and average lesion-specific scores in each vessel were also determined. For the primary analysis, obstructive CAD was defined as 50% diameter stenosis by XRA.
RESULTS: Whole-heart AgSc and VolSc were not different between patients with and without obstructive CAD (P = .23 and P = .18), whereas vessel- and lesion-specific scores were (maximum lesion specific AgSc, P < .0001). Maximum lesion-specific AgSc had superior diagnostic performance compared with whole-heart AgSc (area under receiver operating characteristics, 0.71 vs 0.58). Overall sensitivity, specificity, and diagnostic accuracy were improved. When specificity was fixed at 80%, sensitivity of maximum lesion-specific AgSc was superior to whole-heart AgSc (56.6% vs 35.1%). Most importantly, with lesion-specific AgSc, fewer patients were classified as "indeterminate" compared with whole-heart AgSc (17.9% vs 50%).
CONCLUSIONS: Vessel- and lesion-specific CAC scores are superior to the whole-heart AgSc and VolSc in predicting obstructive CAD. This simple refinement in CAC scoring may significantly improve the clinical predictive role of CAC imaging.