18 Feb 21. Featured Paper

Contrast-enhanced computed tomography assessment of aortic stenosis.

Link to paper on Heart Journal.

Authors

Timothy RG Cartlidge, Rong Bing, Jacek Kwiecinski, Ezequiel Guzzetti, Tania A Pawade, Mhairi K Doris, Philip D Adamson, Daniele Massera, Maria Lembo, Frederique E C M Peeters, Christian Couture, Daniel S Berman, Damini Dey, Piotr Slomka, Philippe Pibarot, David E Newby, Marie-Annick Clavel, Marc R Dweck

Abstract

Objectives: Non-contrast CT aortic valve calcium scoring ignores the contribution of valvular fibrosis in aortic stenosis.

We assessed aortic valve calcific & non-calcific disease using contrast-enhanced CT.

Methods: This was a post hoc analysis of 164 patients (median age 71 (IQR 66–77) years, 78% male) with aortic stenosis (41 mild, 89 moderate, 34 severe; 7% bicuspid) who underwent echocardiography & contrast-enhanced CT as part of imaging studies.

Calcific & non-calcific (fibrosis) valve tissue volumes were quantified & indexed to annulus area, using Hounsfield unit thresholds calibrated against blood pool radiodensity.

The fibrocalcific ratio assessed the relative contributions of valve fibrosis & calcification.

The fibrocalcific volume (sum of indexed non-calcific & calcific volumes) was compared with aortic valve peak velocity &, in a subgroup, histology & valve weight.

Results: Contrast-enhanced CT calcium volumes correlated with CT calcium score (r=0.80, p<0.001) & peak aortic jet velocity (r=0.55, p<0.001).

The fibrocalcific ratio decreased with increasing aortic stenosis severity (mild: 1.29 (0.98–2.38), moderate: 0.87 (1.48–1.72), severe: 0.47 (0.33–0.78), p<0.001) while the fibrocalcific volume increased (mild: 109 (75–150), moderate: 191 (117–253), severe: 274 (213–344) mm³/cm²).

Fibrocalcific volume correlated with ex vivo valve weight (r=0.72, p<0.001).

Compared with the Agatston score, fibrocalcific volume demonstrated a better correlation with peak aortic jet velocity (r=0.59 & r=0.67, respectively), particularly in females (r=0.38 & r=0.72, respectively).

Conclusions: Contrast-enhanced CT assessment of aortic valve calcific & non-calcific volumes correlates with aortic stenosis severity & may be preferable to non-contrast CT when fibrosis is a significant contributor to valve obstruction.

Keywords

• Aortic stenosis
• Computed tomography (CT)
• Contrast-enhanced computed tomography (CT)