Department of Advanced Biomedical Sciences, Federico II University of Naples, Naples, Italy.
BHF Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom.
JACC Cardiovasc Imaging. 2024 Nov;17(11):1351-1362. doi: 10.1016/j.jcmg.2024.06.007. Epub 2024 Aug 7.
Aortic stenosis (AS) is characterized by calcification and fibrosis. The ability to quantify these processes simultaneously has been limited with previous imaging methods.
The purpose of this study was to evaluate the aortic valve fibrocalcific volume by computed tomography (CT) angiography in patients with AS, in particular, to assess its reproducibility, association with histology and disease severity, and ability to predict/track progression.
In 136 patients with AS, fibrocalcific volume was calculated on CT angiograms at baseline and after 1 year. CT attenuation distributions were analyzed using Gaussian-mixture-modeling to derive thresholds for tissue types enabling the quantification of calcific, noncalcific, and fibrocalcific volumes. Scan-rescan reproducibility was assessed and validation provided against histology and in an external cohort.
Fibrocalcific volume measurements took 5.8 ± 1.0 min/scan, demonstrating good correlation with ex vivo valve weight (r = 0.51; P < 0.001) and excellent scan-rescan reproducibility (mean difference -1%, limits of agreement -4.5% to 2.8%). Baseline fibrocalcific volumes correlated with mean gradient on echocardiography in both male and female participants (rho = 0.64 and 0.69, respectively; both P < 0.001) and in the external validation cohort (n = 66, rho = 0.58; P < 0.001). The relationship was driven principally by calcific volume in men and fibrotic volume in women. After 1 year, fibrocalcific volume increased by 17% and correlated with progression in mean gradient (rho = 0.32; P = 0.003). Baseline fibrocalcific volume was the strongest predictor of subsequent mean gradient progression, with a particularly strong association in female patients (rho = 0.75; P < 0.001).
The aortic valve fibrocalcific volume provides an anatomic assessment of AS severity that can track disease progression precisely. It correlates with disease severity and hemodynamic progression in both male and female patients.
主动脉瓣狭窄（AS）的特征是钙化和纤维化。以前的影像学方法在同时定量这些过程方面的能力有限。
本研究旨在通过 CT 血管造影评估 AS 患者的主动脉瓣纤维钙化容积，特别是评估其可重复性、与组织学和疾病严重程度的相关性，以及预测/跟踪进展的能力。
在 136 例 AS 患者中，在基线和 1 年后的 CT 血管造影上计算纤维钙化容积。使用高斯混合模型分析 CT 衰减分布，以得出组织类型的阈值，从而量化钙化、非钙化和纤维钙化容积。评估扫描-再扫描的可重复性，并通过组织学和外部队列进行验证。
纤维钙化容积测量每扫描用时 5.8 ± 1.0 分钟，与离体瓣膜重量有很好的相关性（r = 0.51；P < 0.001），且扫描-再扫描的可重复性极好（平均差值为 1%，一致性界限为 -4.5%至 2.8%）。在男性和女性参与者中，基线纤维钙化容积与超声心动图上的平均梯度相关（rho = 0.64 和 0.69，均 P < 0.001），在外部验证队列（n = 66，rho = 0.58；P < 0.001）中也相关。这种相关性主要是由男性的钙化容积和女性的纤维化容积驱动的。1 年后，纤维钙化容积增加了 17%，与平均梯度的进展相关（rho = 0.32；P = 0.003）。基线纤维钙化容积是预测随后平均梯度进展的最强指标，在女性患者中尤其具有强相关性（rho = 0.75；P < 0.001）。
主动脉瓣纤维钙化容积提供了一种评估 AS 严重程度的解剖学方法，可以精确地跟踪疾病的进展。它与男性和女性患者的疾病严重程度和血液动力学进展相关。
