Evaluation and Clinical Implications of Aortic Valve Calcification Measured by Electron-Beam Computed Tomography

BACKGROUND: Electron-beam computed tomography (EBCT) is used to measure coronary calcification but not for aortic valve calcification (AVC). Its accuracy, association with aortic stenosis (AS) severity, and diagnostic and prognostic value with respect to AVC are unknown. METHODS AND RESULTS: In 30 explanted aortic valves, the AVC score by EBCT (1125+/-1294 Agatston units AU) showed a strong linear correlation (r=0.96, P or =1100 AU provided 93% sensitivity and 82% specificity for diagnosis of severe AS (AVA <1 cm2), with a receiver operator characteristic curve area of 0.89. AVC assessment by echocardiography was often more severe than by EBCT (P<0.0001). During follow-up, 22 patients either died, developed heart failure, or required surgery. With adjustment for age, sex, symptoms, ejection fraction, and AVA, the AVC score was independently predictive of event-free survival (risk ratio 1.06 per 100-AU increment 1.02 to 1.10, P<0.001), even after adjustment for echocardiographic calcifications. CONCLUSIONS: AVC is accurately and reproducibly measured by EBCT and shows a strong association and diagnostic value for severe AS. The curvilinear relationship between AVC and AVA suggests these measures are complementary, and indeed, AVC provides independent outcome information. Thus, AVC is an important measurement in the evaluation of patients with AS.