title: Relation of Dimensionless Index to Long-Term Outcome in Aortic Stenosis With Preserved LVEF.
abstract: OBJECTIVE
  The aim of this study was to assess the role of the dimensionless index (DI) in a registry of patients with aortic stenosis (AS) to objectively establish prognostic DI thresholds for various degrees of AS severity.
  
  
  BACKGROUND
  DI is a classic marker of severity in AS that does not rely on the estimation of the left ventricular outflow tract (LVOT) cross-sectional area. Although DI estimation is straightforward, its outcome implications have never been tested in the context of routine clinical practice.
  
  
  METHODS
  This analysis includes 488 patients with preserved (≥50%) ejection fraction and no or minimal subjective symptoms, diagnosed with ≥ mild AS. DI was computed as the ratio of the LVOT time-velocity integral to that of the aortic valve jet, and on the basis of the correlation with peak aortic jet velocity, the population was divided into 3 groups: DI <0.20, DI 0.20 to 0.25, and DI >0.25.
  
  
  RESULTS
  The 5-year survival free of events (death or need for aortic valve replacement) was 56 ± 3% for DI >0.25, 41 ± 6% for DI 0.20 to 0.25, and 22 ± 5% for DI <0.20 (p for trend <0.001). The risk of events increased linearly with DI <0.25 (adjusted hazard ratio [HR]: 1.14; 95% confidence interval [CI]: 1.05 to 1.29) per 0.05 DI decrement; p = 0.015). On multivariable analysis, compared with patients with DI >0.25, those with DI 0.20 to 0.25 and those with DI <0.20 incurred an excess risk of events (adjusted HR: 1.65; 95% CI: 1.20 to 2.27 for DI 0.20 to 0.25 vs. DI >0.25, and adjusted HR: 2.62; 95% CI: 1.90 to 3.63 for DI <0.20 vs. DI >0.25). The association of DI and outcome was consistent in subgroups, with no interaction between DI outcome prediction and LVOT diameter, body surface area, or index stroke volume (all p for interaction ≥0.10) CONCLUSIONS: Our results demonstrate that the DI is a simple and reliable marker of AS severity with clear prognostic implications. DI <0.25 is associated with an excess risk of events after diagnosis; therefore, this cutoff should be used for AS severity assessment and for therapeutic decisions.
authors.affiliation: Department of Cardiology, University Hospital Amiens, Amiens, France; Department of Cardiology, Hospital of Saint Quentin, Saint Quentin, France.
authors.forename: Dan
authors.initials: D
authors.lastname: Rusinaru
authors.affiliation: Department of Cardiology, University Hospital Amiens, Amiens, France.
authors.forename: Dorothée
authors.initials: D
authors.lastname: Malaquin
authors.affiliation: Groupement des Hôpitaux de l'Institut Catholique de Lille/Faculté libre de médecine, Université Lille Nord de France, Lille, France; INSERM U-1088, Jules Verne University of Picardie, Amiens, France.
authors.forename: Sylvestre
authors.initials: S
authors.lastname: Maréchaux
authors.affiliation: Groupement des Hôpitaux de l'Institut Catholique de Lille/Faculté libre de médecine, Université Lille Nord de France, Lille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Debry
authors.affiliation: Department of Cardiology, University Hospital Amiens, Amiens, France; INSERM U-1088, Jules Verne University of Picardie, Amiens, France. Electronic address: tribouilloy.christophe@chu-amiens.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Tribouilloy
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000175:diagnosis* / Q000503:physiopathology; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D011379:Prognosis; D012720:Severity of Illness Index; D013318:Stroke Volume
keywords: aortic stenosis; dimensionless index; echocardiography; outcome