Valvuloarterial impedance does not improve risk stratification in low-ejection fraction, low-gradient aortic stenosis: results from a multicentre study

Eur J Echocardiogr. 2011 May;12(5):358-63. doi: 10.1093/ejechocard/jer022.


Objectives: 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.

Methods and 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.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Aortic Valve Stenosis / diagnosis
  • Aortic Valve Stenosis / diagnostic imaging*
  • Aortic Valve Stenosis / pathology
  • Confidence Intervals
  • Echocardiography, Stress
  • Female
  • Health Status Indicators
  • Hemodynamics
  • Humans
  • Male
  • Odds Ratio
  • Prognosis
  • Retrospective Studies
  • Risk Assessment / methods
  • Severity of Illness Index
  • Statistics as Topic
  • Statistics, Nonparametric
  • Stroke Volume*
  • Ventricular Function, Left*