Assessment of the severity of mitral stenosis

by Luigi P. Badano, MD, PhD
Department of cardiac, thoracic and vascular sciences, University of Padua, School of Medicine, Padua, Italy

Clinical Case

  • Female, 27 year-old
  • Rheumatic fever at the age of 17
  • Previous diagnosis of mitral stenosis
  • Dyspnoea on effort

Mitral valve area (MVA) planimetry of anatomic area represents the reference method for assessing mitral stenosis (MS) severity because MVA planimetry does not involve hypotheses concerning loading conditions, compliance of cardiac chambers, or the effect of associated valve disease.

However, planimetry requires particular expertise and it’s quite difficult to ensure by 2D that the cross-sectional area actually corresponds to the leaflet tips. Cut planes which are few millimeters away from the tip of the leaflet significantly underestimate the severity of MS

MVA obtained by manual planimetry of the MV orifice on PSAX view is based on the assumption that the opening direction of the MS funnel is parallel to the left ventricular long axis. However, this assumption rarely holds true in clinical practice.

3D echocardiography allows to control the position of the cut plane exactly at the tips of mitral leaflets and to orient it perpendicular to the opening direction of the MS in order to measure the actual narrowest orifice area

With the latest generation of 3D echocardiography scanners the planimetry of the MV can be performed directly either on the volume rendered images (upper left panel) or on the 2D slice obtained at the tips of mitral leaflets (right lower panel)

Key Messages

2D echocardiography:

MVA obtained by manual planimetry of the MV orifice on PSAX view:

  • Requires careful scanning in order to obtain the smallest orifice in space and the largest opening in time
  • May underestimate MS severity, particularly if the MV opening is eccentric
  • May overestimate MS severity with excessive gain settings, in particular when leaflet tips are dense or calcified

3D echocardiography:

MVA planimetry by 3D echocardiography enables:

  • Superior accuracy than MVA planimetry by 2DE (true narrowest orifice area)
  • Higher agreement with invasive MVA than PHT or PISA methods
  • Increased reproducibility, less dependent on operator’s expertise
  • High feasibility also in eccentric/double orifices or after percutaneous MV valvuloplasty
  • Applicability also when there is an inadequate parasternal window

References

  • Zamorano J, Cordeiro P, Sugeng L, Perez de IslaL, Weinert L, Macaya C, Rodriguez E, Lang RM. Real-time three-dimensional echocardiography for rheumatic mitral valve stenosis evaluation: an accurate and novel approach. J Am Coll Cardiol 2004; 43: 2091-6
  • Lang RM, Badano LP, Mor-Avi V et al. Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. J Am Soc Echocardiogr 2015;28(1):1-39.