title: Aortic distensibility independently affects exercise tolerance in patients with dilated cardiomyopathy.
abstract: BACKGROUND
  Peak exercise oxygen consumption (VO2) is crucial for the prognostic stratification of patients with congestive heart failure, but its hemodynamic determinants are still not completely understood. Aortic wall elasticity modulates left ventricular function and coronary blood flow. Whether an increased aortic pulse-wave velocity (PWV), a known marker of arterial stiffness, may predict peak VO2 in patients with dilated cardiomyopathy (DCM) has to be clarified.
  
  
  RESULTS
  A total of 78 patients with clinical diagnosis of DCM (aged 62+/-11 years; female 29%; mean ejection fraction 34+/-9%) were selected. All patients underwent a complete echocardiographic-Doppler evaluation. Aortic PWV was measured by Doppler ultrasonography immediately before the exercise. A bicycle exercise test with expiratory gas exchange monitoring was performed to determine VO2 . Plasma concentration of the amino-terminal propeptide of type III procollagen (PIIINP), a marker of extracellular matrix turnover, was determined. Mean PWV was 5.7+/-2.2 m/s, and VO2 was 16.5+/-4.5 mL x kg(-1) x min(-1). The hemodynamic variables correlated with VO2 were PWV (r=-0.39, P=0.0007) and stroke volume (r=0.38, P=0.002). In a multivariate analysis, PWV (P=0.04) and stroke volume (P=0.05) were independently correlated with VO2 , accounting for 34% of its variance. PIIINP levels correlated with PWV (r=0.35, P=0.002) and a more restrictive diastolic filling pattern (r=0.40, P=0.02).
  
  
  CONCLUSIONS
  Increased aortic stiffness measured by PWV is an independent predictor of peak VO2 and could partially explain exercise intolerance in patients with DCM.
authors.affiliation: Dipartimento di Scienze Biomediche e Chirurgiche, Sezione di Cardiologia, Università degli Studi di Verona, Verona, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonapace
authors.forename: Andrea
authors.initials: A
authors.lastname: Rossi
authors.forename: Mariantonietta
authors.initials: M
authors.lastname: Cicoira
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franceschini
authors.forename: Giorgio
authors.initials: G
authors.lastname: Golia
authors.forename: Luisa
authors.initials: L
authors.lastname: Zanolla
authors.forename: Paolo
authors.initials: P
authors.lastname: Marino
authors.forename: Piero
authors.initials: P
authors.lastname: Zardini
mesh_terms: D001011:Aorta / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D004548:Elasticity; D017079:Exercise Tolerance; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D018608:Ultrasonography, Doppler