title: Grading of mitral regurgitation based on intensity analysis of the continuous wave Doppler signal.
abstract: Echocardiographic methods are used to quantify mitral regurgitation (MR) severity; however, their applicability, accuracy and reproducibility have been debated. We aimed to develop and validate a novel custom-made transthoracic echocardiographic method for grading MR severity based on average pixel intensity (API) analysis of the continuous wave (CW) Doppler envelope.
  
  
  
  MR was assessed in 290 patients using API, colour Doppler imaging, vena contracta width (VCW) and proximal iso-velocity surface area (PISA) method. For the validation of the API method, a pulsatile in vitro cardiac phantom was used.
  
  
  
  Indices of MR severity, such as left ventricular and atrial dimension, pulmonary arterial pressure, significantly cosegregate with API severity (p≤0.002). The API method showed a linear correlation with colour Doppler (r=0.79), VCW (r=0.68), PISA-effective regurgitant orifice area (r=0.72) and PISA-regurgitant volume (r=0.67); p<0.001 for all. The API was significantly more applicable than VCW (95% vs 75% of all patients; p<0.001) and PISA-based methods (65%; p<0.001). Additionally, the API showed a stronger intraobserver and interobserver agreement compared with other methods. Finally, in the in vitro validation, API values showed a strong linear correlation with increasing regurgitant volumes (r=0.81; p<0.001).
  
  
  
  We showed the clinical feasibility and in vitro validation of a novel digital quantitative echocardiographic method to grade MR severity. This method is more applicable and has less interobserver and intraobserver variability compared with current quantitative methods.
authors: Department of Cardiology, Heart Center, Ghent University Hospital, Ghent, Belgium.
authors: Milad
authors: M
authors: El Haddad
authors: Department of Cardiology, Heart Center, Ghent University Hospital, Ghent, Belgium.
authors: Tine
authors: T
authors: De Backer
authors: Department of Cardiology, Heart Center, Ghent University Hospital, Ghent, Belgium.
authors: Marc
authors: M
authors: De Buyzere
authors: Department of Cardiology, Heart Center, Ghent University Hospital, Ghent, Belgium.
authors: Daniel
authors: D
authors: Devos
authors: Institute of Biomedical Technology, bioMMeda, Ghent University, Ghent, Belgium.
authors: Abigail
authors: A
authors: Swillens
authors: Institute of Biomedical Technology, bioMMeda, Ghent University, Ghent, Belgium.
authors: Patrick
authors: P
authors: Segers
authors: Department of Cardiology, Heart Center, Ghent University Hospital, Ghent, Belgium.
authors: Frank
authors: F
authors: Timmermans
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D018618:Echocardiography, Doppler, Color / Q000295:instrumentation; D005240:Feasibility Studies; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015588:Observer Variation; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index