title: New estimate of valvuloarterial impedance in aortic valve stenosis: A cardiac magnetic resonance study.
abstract: Valvuloarterial impedance (ZVA), estimating left ventricle (LV) afterload, has been proposed in transthoracic echocardiography (TTE) as a predictor of mortality in aortic valve stenosis (AVS). However, its calculation differs from arterial characteristic impedance (ZC). Our aim was to apply the concept of ZCcalculation to estimate ZVAfrom MR with carotid tonometry and to evaluate these indices through their associations with symptoms, LV diastolic function and aortic stiffness.
  
  
  
  In 40 patients with AVS (76 ± 13 years), ZVA-TIderived from velocity time integral and E/Ea were estimated by TTE. ZVA-INS, based on ZCformula, calculated as the instantaneous pressure gradient to peak flow ratio and aortic compliance were estimated by using MRI at 1.5 Tesla.
  
  
  
  Both ZVAestimates were higher in symptomatic than asymptomatic patients (707 ± 22 versus 579 ± 53 dyne.s/cm5, P = 0.031 for ZVA-INSand 4.35 ± 0.16 versus 3.33 ± 0.38 mmHg.m2/mL, P = 0.018 for ZVA-TI). Although they were both associated with aortic compliance (r = -0.45; P = 0.006 for ZVA-INSand r = -0.43; P = 0.008 for ZVA-TI) only ZVA-INSwas associated with E/Ea (r = 0.50; P < 0.001). In multivariate analysis to identify determinants of E/Ea, a model including age, mean blood pressure, LV ejection fraction, LV mass, and aortic valve area was performed (R2= 0.41; P < 0.01). When ZVA-INSwas added to the model, its overall significance was higher R2= 0.56 (P < 0.01) and ZVA-INSand LV mass were the only significant determinants.
  
  
  
  ZVA-INSwas more strongly associated with diastolic dysfunction than usual parameters quantifying AVS severity. This new ZVAestimate could improve LV afterload evaluation.
  
  
  
  1 J. Magn. Reson. Imaging 2017;45:795-803.
authors.affiliation: INSERM UMR 970, Paris-Cardiovascular research Center, Paris, France.|Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Soulat
authors.affiliation: Sorbonne Universités, UPMC, INSERM 1146, CNRS 7371, Laboratoire d'Imagerie Biomédicale, Paris.
authors.forename: Nadjia
authors.initials: N
authors.lastname: Kachenoura
authors.affiliation: Sorbonne Universités, UPMC, INSERM 1146, CNRS 7371, Laboratoire d'Imagerie Biomédicale, Paris.
authors.forename: Emilie
authors.initials: E
authors.lastname: Bollache
authors.affiliation: Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.
authors.forename: Ludivine
authors.initials: L
authors.lastname: Perdrix
authors.affiliation: Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Diebold
authors.affiliation: Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.|INSERM CIC1418, Paris, France.
authors.forename: Valentina
authors.initials: V
authors.lastname: Zhygalina
authors.affiliation: INSERM UMR 970, Paris-Cardiovascular research Center, Paris, France.|Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Latremouille
authors.affiliation: INSERM UMR 970, Paris-Cardiovascular research Center, Paris, France.|Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Laurent
authors.affiliation: Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Jean-Noel
authors.initials: JN
authors.lastname: Fabiani
authors.affiliation: INSERM UMR 970, Paris-Cardiovascular research Center, Paris, France.|Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, Paris, France.|Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
authors.forename: Elie
authors.initials: E
authors.lastname: Mousseaux
mesh_terms: D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D003198:Computer Simulation; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014655:Vascular Resistance; D059289:Vascular Stiffness
keywords: aortic valve stenosis; cardiac magnetic resonance; valvuloarterial impedance