Management of organic mitral regurgitation: guideline recommendations and controversies

Abstract

Mitral regurgitation (MR) represents the second most frequent valvular heart disease. The appropriate management of organic MR remains unclear in many aspects, especially in several specific clinical scenarios. This review aims to discuss the current guideline recommendations regarding the management of organic MR, while highlighting the controversial aspects encountered in daily clinical practice. The role of imaging is essential in establishing the most appropriate type of surgical treatment (repair or replace), which is based on morphological mitral valve (MV) characteristics (reparability of the valve) and local surgical expertise in valve repair. The potential advantages of 3-dimensional echocardiography in assessing the MV are discussed. Other modern imaging techniques (tissue Doppler and speckle tracking) may provide additional useful information in borderline cases. Exercise echocardiography (evaluating MR severity, pulmonary pressure, or right ventricular function) may have an important role in the management of difficult cases. Finally, the moment when surgery is no longer an option and alternative solutions should be sought is also discussed. Although in everyday clinical practice the timing of surgery is not always straightforward, some newer clinical and echocardiographic indicators can guide this decision and help improve the outcome of these patients.

Keywords: Echocardiography; Mitral annuloplasty; Mitral regurgitation.

Fig. 1. Mitral valve lesions in severe organic mitral regurgitation, assessed by three-dimensional transoesophageal echocardiography. A: severe mitral regurgitation determined by a simple lesion with a high probability of successful mitral valve repair. 3D transoesophageal surgical view of the mitral valve showing isolated P2 scallop prolapse (asterisk) (Supplementary Video 1 in the online-only Data Supplement). B: severe mitral regurgitation determined by complex lesions with a possibly successful mitral valve repair by an experienced surgeon. 3D transoesophageal surgical view of the mitral valve showing P3 scallop prolapse and flail (asterisk) involving the posterior commissure (Supplementary Video 2 in the online-only Data Supplement). C: severe mitral regurgitation determined by a very complex lesion with an unlikely chance of successful mitral valve repair. 3D transoesophageal surgical view in a patient with Barlow disease and P2 flail (asterisk) (Supplementary Video 3 in the online-only Data Supplement). 3D: three-dimensional.

Fig. 2. Mitral valve assessment in a patient with severe mitral regurgitation. A: 2D transoesophageal four chamber view of posterior mitral valve prolapse and flail due to chordal rupture (arrow) (Supplementary Video 4 in the online-only Data Supplement). B: 3D transoesophageal view of the mitral valve seen from the left atrium showing isolated P2 prolapse and flail (asterisk) (Supplementary Video 5 in the online-only Data Supplement). C: 3D mitral valve reconstruction demonstrating P2 prolapse (color coded in red). D: intraoperative findings confirming the echo results: P2 scallop chordal rupture (asterisk). 2D: two-dimensional, 3D: three-dimensional.

Fig. 3. Mitral valve reconstruction in a normal subject (A) and in a patient with severe mitral regurgitation due to P2 scallop flail and prolapse and P3 scallop prolapse (B). The parts of the mitral valve which are below the mitral annulus plane (i.e., on the ventricular side) are color-coded in blue, while the parts which are above annulus are coded in red. Of note, the shape of the mitral annulus changes in MR, becoming circular (B), compared to the oval shape of the normal mitral annulus (A). MR: metral regurgitation.

Fig. 4. Echocardiographic images from a patient with severe asymptomatic mitral regurgitation. There is a preserved left ventricular (LV) ejection fraction calculated by Simpson's method (61%) (A), but reduced global longitudinal strain (-14.3%) (B), suggesting subclinical LV systolic dysfunction (Supplementary Video 6 in the online-only Data Supplement). LVEF: left ventricular ejection fraction, SV: stroke volume, LVESV: left ventricular end systolic volume, LVEDV: left ventricular end diastolic volume.

Fig. 5. Left atrium (LA) function evaluation in a patient with severe asymptomatic mitral regurgitation (MR). The LA ejection fraction calculated by LA maximum volume (130 mL in A)-LA minimum volume (80 mL in B) divided by LA maximum volume is decreased to 38%. The LA strain values (i.e., reservoir, conduit, and contractile function) calculated by speckle tracking imaging (C) in the same patient with severe asymptomatic MR are decreased.