title: Circumferential ascending aortic strain and aortic stenosis.
abstract: BACKGROUND
  Two-dimensional speckle tracking (2D-ST) echocardiography for the measurement of circumferential ascending thoracic aortic strain (CAAS) in the context of aortic stenosis (AS) is not elucidated. Purpose This study assesses the thoracic ascending aortic deformation using 2D-ST echocardiography in AS patients. Population and methods Forty-five consecutive patients with an aortic valvular area (AVA) ≤0.85 cm(2)/m(2) were included. Regarding aortic deformation, the global peak CAAS was the parameter used, and an average of six segments of arterial wall deformation was calculated. The corrected CAAS was calculated as the global CAAS/pulse pressure (PP). Aortic stiffness (β2) index was assessed according to ln(Ps/Pd)/CAAS. The sample was stratified according to the stroke volume index (SVI) as: Group A (low flow, SVI ≤35 mL/m(2); n = 19) and Group B (normal flow, SVI >35 mL/m(2); n = 26).
  
  
  RESULTS
  The mean age was 76.8 ± 10.3 years, 53.3% were male, the mean indexed AVA was 0.43 ± 0.15 cm(2)/m(2), and the mean CAAS was 6.3 ± 3.0%. The CAAS was predicted by SVI (β = 0.31, P < 0.01) and by valvulo-arterial impedance (Zva). The corrected CAAS was correlated with the M-mode guided aortic stiffness index (β1) (r = -0.39, P < 0.01), and was predicted by SVI, Zva, and systemic arterial compliance (β = 0.15, P < 0.01). The β2 index was significantly higher for the low-flow patients (16.1 ± 4.8 vs. 9.8 ± 5.3, P < 0.01), and was predicted by SVI (β -0.58, P < 0.01) and PP (β = 0.17, P < 0.01). Global CAAS was more accurate to predict low flow than Zva, systolic function and systemic vascular resistance.
  
  
  CONCLUSIONS
  In patients with moderate-to-severe aortic stenosis, SVI and LV afterload-related variables were the most important determinants of 2S-ST global CAAS.
authors.affiliation: Serviço de Cardiologia, Centro Hospitalar e Universitario de Coimbra, Av. Bissaya Barreto Praceta Prof. Mota Pinto, Coimbra, Portugal. rogeriopteixeira@gmail.com
authors.forename: Rogério
authors.initials: R
authors.lastname: Teixeira
authors.forename: Nádia
authors.initials: N
authors.lastname: Moreira
authors.forename: Rui
authors.initials: R
authors.lastname: Baptista
authors.forename: António
authors.initials: A
authors.lastname: Barbosa
authors.forename: Rui
authors.initials: R
authors.lastname: Martins
authors.forename: Graça
authors.initials: G
authors.lastname: Castro
authors.forename: Luís
authors.initials: L
authors.lastname: Providência
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D015331:Cohort Studies; D004452:Echocardiography / Q000379:methods*; D018619:Echocardiography, Doppler, Pulsed / Q000379:methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013318:Stroke Volume; D014655:Vascular Resistance; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: 2D-ST strain imaging; Aortic stenosis; Circumferential ascending aortic strain; Low flow