Total fibrocalcific volume (FCV) quantification by CT was less accurate (C-statistic 0.65) than calcium scoring (VCaS, C-statistic 0.79) for identifying severe aortic stenosis.
Does quantification of total fibrocalcific volume using a novel CT method outperform calcium scoring in identifying severe aortic stenosis?
Quantification of total fibrocalcific volume using a novel CT method did not outperform standard calcium scoring in identifying severe aortic stenosis.
Absolute Event Rate: 0% vs 0%
Abstract Introduction Calcium scoring of the aortic valve (VCaS) is a useful tool for assessing severity of aortic stenosis (AS), but focuses solely on the calcific component, overlooking the contribution of fibrosis. Recently, a novel method for quantifying both fibrosis and calcification of the aortic valve in contrast-enhanced CT has been developed and validated histologically. This study aimed to characterize the fibrocalcific burden of the aortic valves of patients with AS undergoing cardiac CT, and compare its discriminative value with VCaS. Methods This single center retrospective study included patients with isolated degenerative AS with normal flow conditions on transthoracic echocardiogram (performed within 6 months) who underwent cardiac CT for the workup of known or suspected severe AS. Fibrotic volume, calcific volume and fibrocalcific volume (FCV) were calculated on CT images according to the new methodology, using Gaussian-mixture-modeling to derive scan-specific thresholds for calcific and fibrotic tissue. Results A total of 246 patients were included (mean age 81 ± 7 years; 64% female). Overall, 198 patients had severe aortic AS and 48 had moderate AS. Population characteristics are described in Table 1. FCV and fibrotic volume showed poor correlation with mean gradient (rho = 0.280, p 0.001; rho=0.125, p=0.051, respectively). Median FCV was higher in patients with severe AS than in those with moderate AS (2616 vs. 2037 mm3; p=0.025). This difference was mainly due to increased calcium content (714 vs 420 mm3; p=0.021), as there were no differences in fibrotic content between groups (1830 vs 1310; p=0.126). Total fibrotic volume was not different between genders, but the fibrocalcific ratio (fibrous / calcific volume) was higher in females with severe AS (p0.001). FCV showed a C-statistic of 0.65 (95%CI 0.56– 0.75; p=0.001) for prediction of severe AS. However, VCaS remained superior to FCV in predicting severe AS (C-statistic 0.79 (95%CI 0.71-0.86, p0.001), p0.001 for comparison between the two. The discriminative power of VCaS remained superior to FCV in both men and women. Results remained similar when FCV or its individual components were indexed to the patient’s aortic annulus dimensions. A small group of patients (n=17) underwent a second CT during follow-up (median interscan time 917 days, IQR 475-1595). An increase in both fibrosis and calcium was noted, with a significant rise in total fibrocalcific content over time (p=0.045). Conclusion The fibrous and calcific components of the aortic valve differ significantly between patients, vary by sex, and evolve over time. However, the quantification of total fibrocalcific volume did not outperform calcium score in identifying severe AS. Further studies in larger cohorts are warranted to explore the clinical relevance of fibrosis quantification, particularly in female patients.
Bello et al. (Sat,) reported a other. Total fibrocalcific volume (FCV) quantification by CT was less accurate (C-statistic 0.65) than calcium scoring (VCaS, C-statistic 0.79) for identifying severe aortic stenosis.