title: Doppler echocardiography markedly underestimates left ventricular stroke work loss in severe aortic valve stenosis.
abstract: OBJECTIVE
  Left ventricular (LV) stroke work loss (SWL) is an index of aortic stenosis (AS) severity based on the energy loss concept. Traditionally known as an invasive measurement, SWL has also been determined noninvasively using Doppler echocardiography. The present work was done to compare the echocardiographic estimate against the standard invasive SWL.
  
  
  RESULTS
  We determined SWL in 113 adult patients with AS at cardiac catheterization (mean gradient as percentage of the LV mean systolic pressure) and by Doppler echocardiography (mean gradient as percentage of the sum of systolic cuff blood pressure and mean gradient). SWL averaged 26.5+/-0.6% by echocardiography vs 30.9+/-0.8% by catheterization (p<0.0000001). The underestimation by echocardiography was the worse the higher the invasive SWL was (p<0.00001). Echocardiographic SWL exceeding 25% (previously suggested cutoff) had a sensitivity of 64% and specificity of 74% to identify severe AS (Gorlin valve area<0.5 cm(2)/m(2)). Several patients with severe AS by valve area had echocardiographic SWL suggesting only mild AS.
  
  
  CONCLUSIONS
  In AS, echocardiography gives a biased estimate of LV SWL with marked underestimation in severe disease. Echocardiographic SWL may confuse rather than improve the assessment of AS in clinical practice.
authors.affiliation: Division of Cardiology, Department of Medicine, Helsinki University Central Hospital, Haartmaninkatu 4, 00029 Helsinki, Finland.
authors.forename: Heikki
authors.initials: H
authors.lastname: Turto
authors.forename: Jyri
authors.initials: J
authors.lastname: Lommi
authors.forename: Markku
authors.initials: M
authors.lastname: Ventilä
authors.forename: Markku
authors.initials: M
authors.lastname: Kupari
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006328:Cardiac Catheterization / Q000379:methods; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000502:physiology*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*