Aortic valve calcium score from computed tomography for signal localization by cardiac amyloid radionuclide imaging to predict aortic stenosis and assess prognosis in patients with transthyretin cardiomyopathy.

Abstract

PURPOSE: Transthyretin cardiomyopathy (ATTR-CM) and aortic stenosis (AS) are frequently associated. The diagnosis of ATTR-CM can be made by performing a cardiac amyloid radionuclide imaging (CARI) with a computed tomography (CT) scan to localize the signal, which allows visualization aortic valve calcifications (AVC). The aim of this study was to determine whether AVC on the CT performed at the time of the CARI for the diagnosis of ATTR-CM were predictive of AS and had an impact on prognosis. METHODS: CT images of patients diagnosed with ATTR-CM by CARI were reviewed for the presence of AVC and the calcium score was calculated. A three-stage visual score for AVC was developed (score 0, absence; score 1, < 50% of the annulus; score 2, ≥ 50% of the annulus). AVC were then compared with the aortic valve hemodynamic parameters by echocardiography. RESULTS: 263 patients were included. AVC were present in 153 (58%) patients. The median calcium score was 430 [200–1140]. A cut-off calcium score value ≥ 380 predicted an AS with a sensitivity of 91% and a specificity of 81%. For severe AS, a threshold of ≥ 1690 yielded an area under the curve of 0,98 (95%CI: 0.95–1.00, P < 0.0001). A visual score of 2 predicted severe AS with 94% sensitivity and 90% specificity. After multivariate analysis, both the aortic valve calcium score and visual score were independent predictors of all-cause mortality. CONCLUSION: Aortic valve calcium score and semi-quantitative visual score are predictors of AS severity and mortality.