title: Flow-gradient patterns in severe aortic stenosis with preserved ejection fraction: clinical characteristics and predictors of survival.
abstract: BACKGROUND
  Among patients with severe aortic stenosis (AS) and preserved ejection fraction, those with low gradient (LG) and reduced stroke volume may have an adverse prognosis. We investigated the prognostic impact of stroke volume using the recently proposed flow-gradient classification.
  
  
  RESULTS
  We examined 1704 consecutive patients with severe AS (aortic valve area <1.0 cm(2)) and preserved ejection fraction (≥50%) using 2-dimensional and Doppler echocardiography. Patients were stratified by stroke volume index (<35 mL/m(2) [low flow, LF] versus ≥35 mL/m(2) [normal flow, NF]) and aortic gradient (<40 mm Hg [LG] versus ≥40 mm Hg [high gradient, HG]) into 4 groups: NF/HG, NF/LG, LF/HG, and LF/LG. NF/LG (n=352, 21%), was associated with favorable survival with medical management (2-year estimate, 82% versus 67% in NF/HG; P<0.0001). LF/LG severe AS (n=53, 3%) was characterized by lower ejection fraction, more prevalent atrial fibrillation and heart failure, reduced arterial compliance, and reduced survival (2-year estimate, 60% versus 82% in NF/HG; P<0.001). In multivariable analysis, the LF/LG pattern was the strongest predictor of mortality (hazard ratio, 3.26; 95% confidence interval, 1.71-6.22; P<0.001 versus NF/LG). Aortic valve replacement was associated with a 69% mortality reduction (hazard ratio, 0.31; 95% confidence interval, 0.25-0.39; P<0.0001) in LF/LG and NF/HG, with no survival benefit associated with aortic valve replacement in NF/LG and LF/HG.
  
  
  CONCLUSIONS
  NF/LG severe AS with preserved ejection fraction exhibits favorable survival with medical management, and the impact of aortic valve replacement on survival was neutral. LF/LG severe AS is characterized by a high prevalence of atrial fibrillation, heart failure, and reduced survival, and aortic valve replacement was associated with improved survival. These findings have implications for the evaluation and subsequent management of AS severity.
authors.affiliation: Division of Cardiovascular Diseases, Department of Medicine (M.F.E., P.S., H.I.M., J.F.M., P.A.P.), and Division of Biostatistics (C.G.S.), Mayo Clinic College of Medicine, Rochester, MN.
authors.forename: Mackram F
authors.initials: MF
authors.lastname: Eleid
authors.forename: Paul
authors.initials: P
authors.lastname: Sorajja
authors.forename: Hector I
authors.initials: HI
authors.lastname: Michelena
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Malouf
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Scott
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Pellikka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000401:mortality* / Q000503:physiopathology* / Q000601:surgery; D001281:Atrial Fibrillation / Q000401:mortality / Q000503:physiopathology; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000401:mortality; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology*
keywords: echocardiography; heart valves; surgery; survival; valves
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