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Original article
Grading of mitral regurgitation based on intensity analysis of the continuous wave Doppler signal
  1. Milad El Haddad1,
  2. Tine De Backer1,
  3. Marc De Buyzere1,
  4. Daniel Devos1,
  5. Abigail Swillens2,
  6. Patrick Segers2,
  7. Frank Timmermans1
  1. 1Department of Cardiology, Heart Center, Ghent University Hospital, Ghent, Belgium
  2. 2Institute of Biomedical Technology, bioMMeda, Ghent University, Ghent, Belgium
  1. Correspondence to Dr Frank Timmermans, Department of Cardiology, University Hospital Ghent, 10-K12; De Pintelaan 185, Ghent 9000, Belgium; frank.timmermans{at}


Objectives 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.

Methods 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.

Results 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).

Conclusions 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.

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  • Contributors FT and MEH designed, initiated, executed and performed the analyses of the study. FT, TDB and DD acquired the study's clinical data. MDB provided statistical analysis. AS and PS provided assistance in the experimental validation. All coauthors contributed to the manuscript drafting.

  • Competing interests None declared.

  • Ethics approval Local Ethical Committee at Ghent University and Ghent University Hospital.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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