Personne :
Guzzetti, Ezequiel

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Université Laval
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  • Publication
    Validation of aortic valve calcium quantification thresholds measured by computed tomography in Asian patients with calcific aortic stenosis
    (Oxford University Press, 2021-06-25) Guzzetti, Ezequiel; Oh, Kyung Jin; Shen, Mylène; Pibarot, Philippe; Dweck, Marc R.; Clavel, Marie-Annick; Poh, Kian Keong; Tastet, Lionel; Abbas, Amr E.; Mando, Ramy; Pressman, Gregg; Brito, Daniel; Pawade, Tania; Falconi, Mariano Luis; Arenaza, Diego Perez de; Kong, William
    Aims Sex-specific thresholds of aortic valve calcification (AVC) have been proposed and validated in Caucasians. Thus, we aimed to validate their accuracy in Asians. Methods and results Patients with calcific aortic stenosis (AS) from seven international centres were included. Exclusion criteria were ≥moderate aortic/mitral regurgitation and bicuspid valve. Optimal AVC and AVC-density sex-specific thresholds for severe AS were obtained in concordant grading and normal flow patients (CG/NF). We included 1263 patients [728 (57%) Asians, 573 (45%) women, 837 (66%) with CG/NF]. Mean gradient was 48 (26–64) mmHg and peak aortic velocity 4.5 (3.4–5.1) m/s. Optimal AVC thresholds were: 2145 Agatston Units (AU) in men and 1301 AU in women for Asians; and 1885 AU in men and 1129 AU in women for Caucasians. Overall, accuracy (% correctly classified) was high and comparable either using optimal or guidelines’ thresholds (2000 AU in men, 1200 AU in women). However, accuracy was lower in Asian women vs. Caucasian women (76–78% vs. 94–95%; P < 0.001). Accuracy of AVC-density (476 AU/cm2 in men and 292 AU/cm2 in women) was comparable to absolute AVC in Caucasians (91% vs. 91%, respectively, P = 0.74), but higher than absolute AVC in Asians (87% vs. 81%, P < 0.001). There was no interaction between AVC/AVC-density and ethnicity (all P > 0.41) with regards to AS haemodynamic severity. Conclusion AVC thresholds defining severe AS are comparable in Asian and Caucasian populations, and similar to those proposed in the guidelines. However, accuracy of AVC to identify severe AS in Asians (especially women) is sub-optimal. Therefore, the use of AVC-density is preferable in Asians.
  • Publication
    Accès libre
    Contrast-enhanced computed tomography assessment of aortic stenosis.
    (2021-01-29) Timothy Robert, Graham Cartlidge; Guzzetti, Ezequiel; Bing, Rong; Couture, Christian; Kwiecinski, Jacek; Pibarot, Philippe; Clavel, Marie-Annick; Pawade, Tania; Doris, Mhairi K; Adamson, Philip D; Massera, Daniele; Lembo, Maria; Peeters, Frederique E. C. M.; Berman, Daniel S; Dey, Damini; Slomka, Piotr; Newby, David E; Dweck, Marc R
    Abstract Objectives Non-contrast CT aortic valve calcium scoring ignores the contribution of valvular fibrosis in aortic stenosis. We assessed aortic valve calcific and 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 and contrast-enhanced CT as part of imaging studies. Calcific and non-calcific (fibrosis) valve tissue volumes were quantified and indexed to annulus area, using Hounsfield unit thresholds calibrated against blood pool radiodensity. The fibrocalcific ratio assessed the relative contributions of valve fibrosis and calcification. The fibrocalcific volume (sum of indexed non-calcific and calcific volumes) was compared with aortic valve peak velocity and, in a subgroup, histology and valve weight. Results Contrast-enhanced CT calcium volumes correlated with CT calcium score (r=0.80, p<0.001) and 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 and r=0.67, respectively), particularly in females (r=0.38 and r=0.72, respectively). Conclusions Contrast-enhanced CT assessment of aortic valve calcific and non-calcific volumes correlates with aortic stenosis severity and may be preferable to non-contrast CT when fibrosis is a significant contributor to valve obstruction.
  • Publication
    Accès libre
    Multiplanar "En Face" reconstruction of the aortic valve : impact on aortic valve calcium
    (American College of Cardiology Foundation, 2020-07-29) Clisson, Marine; Guzzetti, Ezequiel; Clavel, Marie-Annick; Simard, Louis
  • Publication
    Accès libre
    Why and how to measure aortic valve calcification in patients with aortic stenosis
    (Elsevier, 2019-09-02) Pawade, Tania; Guzzetti, Ezequiel; Sheth, Tej; Clavel, Marie-Annick; Dweck, Marc
    The first-line evaluation of aortic stenosis severity is Doppler echocardiography. However, in up to 40% of patients, resting echocardiographic assessment of aortic stenosis severity is discordant, leading to clinical uncertainty. Interest has therefore grown in aortic valve calcium scoring by multidetector computed tomography (CT-AVC) as an alternative load independent assessment of aortic stenosis severity. This paper will briefly review the pathophysiology of aortic stenosis and the crucial role that calcification plays in driving progressive obstruction of the valve. Subsequently, it will describe published reports that have investigated CT-AVC, validating this parameter against histology, and establishing its diagnostic accuracy versus echocardiography as well as its powerful independent prognostic capability. Finally, this review seeks to provide a practical guide about how best to acquire and interpret CT-AVC with a close focus on potential pitfalls and how these might be best avoided as this technique becomes more widely adopted in to clinical practice.