title: Valvuloarterial impedance does not improve risk stratification in low-ejection fraction, low-gradient aortic stenosis: results from a multicentre study.
abstract: OBJECTIVE
  In a multicentre series of patients with low-ejection fraction/low-gradient aortic stenosis (LEF/LGAS), we evaluated the prognostic impact of valvuloarterial impedance (Zva).
  
  
  BACKGROUND
  Zva in AS, a measure of global afterload taking into account systemic arterial compliance, has been proposed for risk stratification in paradoxical LGAS. We hypothesized that Zva could help risk stratification in LEF/LGAS.
  
  
  RESULTS
  We retrospectively calculated Zva (5.6 ± 1.7 mmHg/mL/m(2)) of 184 consecutive patients (mean age: 71 ± 10 years) with severe symptomatic LEF/LGAS (valve area ≤1 cm2;, EF ≤40%, mean transaortic pressure gradient ≤40 mmHg) included between 1995 and 2005 in a multicentre registry. Zva was higher in patients with LVEF at rest ≤20% (6.6 ± 2.3 vs. 5.5 ± 1.6; P = 0.05) and correlated negatively with LVEF at rest (R = -0.25; P = 0.001). Zva was lower in patients without contractile reserve (CR) on dobutamine stress echocardiography (DSE) compared with patients with true severe AS (5.3 ± 1.3 vs. 5.8 ± 1.8 mmHg/mL/m(2); P = 0.048). Zva and the variation in stroke volume during DSE were positively correlated (P = 0.0001) but Zva did not allow distinction between true and pseudo-severe AS (5.8 ± 1.8 vs. 5.3 ± 1.8 mm Hg/mL/m(2); P = 0.30). In the total population, Zva was not predictive of long-term mortality. In the 128 patients who underwent aortic valve replacement, Zva was not predictive of operative death and of long-term mortality.
  
  
  CONCLUSIONS
  Increased Zva is related to low LVEF and more frequent CR on DSE in LEF/LGAS. However, Zva did not allow an accurate distinction between true and pseudo-severe AS and failed to predict operative and long-term mortality after aortic valve replacement, in LEF/LGAS.
authors.affiliation: Department of Cardiology and INSERM and ERI-12, University Hospital, Amiens, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Levy
authors.forename: Jean
authors.initials: J
authors.lastname: Luc Monin
authors.forename: Dan
authors.initials: D
authors.lastname: Rusinaru
authors.forename: Hélène
authors.initials: H
authors.lastname: Petit-Eisenmann
authors.forename: Claude
authors.initials: C
authors.lastname: Lelguen
authors.forename: Christophe
authors.initials: C
authors.lastname: Chauvel
authors.forename: Catherine
authors.initials: C
authors.lastname: Adams
authors.forename: Damien
authors.initials: D
authors.lastname: Metz
authors.forename: Francois
authors.initials: F
authors.lastname: Leleu
authors.forename: Pascal
authors.initials: P
authors.lastname: Gueret
authors.forename: Christophe
authors.initials: C
authors.lastname: Tribouilloy
mesh_terms: D000368:Aged; D001024:Aortic Valve Stenosis / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D016001:Confidence Intervals; D025401:Echocardiography, Stress; D005260:Female; D006305:Health Status Indicators; D006439:Hemodynamics; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012720:Severity of Illness Index; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013318:Stroke Volume; D016277:Ventricular Function, Left