Aortic Valve Calcification Density Measured by MDCT in the Assessment of Aortic Stenosis Severity

BACKGROUND: Aortic valve calcification (AVC) indexation to the aortic annulus (AA) area measured by Doppler echocardiography (AVCdEcho) provides powerful prognostic information in patients with aortic stenosis (AS). However, the indexation by AA measured by multidetector computed tomography (AVCdCT) has never been evaluated. The aim of this study was to compare AVC, AVCdCT, and AVCdEchowith regard to hemodynamic correlations and clinical outcomes in patients with AS. METHODS: Data from 889 patients, mainly White, with calcific AS who underwent Doppler echocardiography and multidetector computed tomography within the same episode of care were retrospectively analyzed. AA was measured both by Doppler echocardiography and multidetector computed tomography. AVCdCTseverity thresholds were established using receiver operating characteristic curve analyses in men and women separately. The primary end point was the occurrence of all-cause mortality. RESULTS: Correlations between gradient/velocity and AVCd were stronger (both P≤0.005) using AVCdCT(r=0.68, P<0.001 and r=0.66, P<0.001) than AVC (r=0.61, P<0.001 and r=0.60, P<0.001) or AVCdEcho(r=0.61, P<0.001 and r=0.59, P<0.001). AVCdCTthresholds for the identification of severe AS were 334 Agatston units (AU)/cm2for women and 467 AU/cm2for men. On a median follow-up of 6.62 (6.19-9.69) years, AVCdCTratio was superior to AVC ratio and AVCdEchoratio to predict all-cause mortality in multivariate analyses (hazard ratio HR, 1.59 95% CI, 1.26-2.00; P<0.001 versus HR, 1.53 95% CI, 1.11-1.65; P=0.003 versus HR, 1.27 95% CI, 1.11-1.46; P<0.001; all likelihood test P≤0.004). AVCdCTratio was superior to AVC ratio and AVCdEchoratio to predict survival under medical treatment in multivariate analyses (HR, 1.80 95% CI, 1.27-1.58; P<0.001 compared with HR, 1.55 95% CI, 1.13-2.10; P=0.007; HR, 1.28 95% CI, 1.03-1.57; P=0.01; all likelihood test P<0.03). AVCdCTratio predicts mortality in all subgroups of patients with AS. CONCLUSIONS: AVCdCTappears to be equivalent or superior to AVC and AVCdEchoto assess AS severity and predict all-cause mortality. Thus, it should be used to evaluate AS severity in patients with nonconclusive echocardiographic evaluations with or without low-flow status. AVCdCTthresholds of 300 AU/cm2for women and 500 AU/cm2for men seem to be appropriate to identify severe AS. Further studies are needed to validate these thresholds, especially in diverse populations.