Automated quantification of mitral valve tenting volume in functional mitral regurgitation by three‐dimensional echocardiography

Echocardiographic quantification of mitral apparatus morphology and dynamics in patients with dilated cardiomyopathy

Mitral regurgitation is among the most common valvular heart diseases. Mitral regurgitation in patients with dilated cardiomyopathy is a complex pathology involving annular dilatation, papillary muscle displacement, systolic leaflet tethering, and left ventricular remodeling. Quantification of mitral apparatus damage in these patients is essential for successful interventional and surgical therapy. Mitral regurgitation in the presence of dilated cardiomyopathy is classified as Carpentier type IIIB, with restricted leaflet mobility as a standard feature. Echocardiography allows accurate evaluation of the complex anatomy and function of the mitral apparatus. Updated guidelines recommend two-dimensional followed by systematic three-dimensional echocardiographic evaluation in patients with mitral regurgitation. New three-dimensional echocardiographic software packages provide many parameters that help identify the precise morphology and function of the various components of the mitral apparatus, helping to determine the etiology of mitral regurgitation and evaluate disease severity. This review provides the first point-by-point approach to the assessment of all old and new echocardiographic methods, from the simplest to the most complex, used to examine the components of the mitral valve apparatus in patients with dilated cardiomyopathy. Although these parameters are still under research, this information will be helpful for establishing therapeutic procedures in a disease with a poor prognosis.

Parameters of the mitral apparatus in patients with ischemic and nonischemic dilated cardiomyopathy

The mitral valve apparatus is a complex structure consisting of several coordinating components: the annulus, two leaflets, the chordae tendineae, and the papillary muscles. Due to the intricate interplay between the mitral valve and the left ventricle, a disease of the latter may influence the normal function of the former. As a consequence, valve insufficiency may arise despite the absence of organic valve disease. This is designated as functional or secondary mitral regurgitation, and it arises from a series of distortions to the valve components. This narrative review describes the normal anatomy and the pathophysiology behind the mitral valve changes in ischemic and non-ischemic dilated cardiomyopathies. It also explains the value of a complete multiparametric assessment of this structure. Not only must an assessment include quantitative measures of regurgitation, but also various anatomical parameters from the mitral apparatus and left ventricle, since they carry prognostic value and are predictors of mitral valve repair success and durability.

Echocardiographic Advances in Dilated Cardiomyopathy

Although the overall survival of patients with dilated cardiomyopathy (DCM) has improved significantly in the last decades, a non-negligible proportion of DCM patients still shows an unfavorable prognosis. DCM patients not only need imaging techniques that are effective in diagnosis, but also suitable for long-term follow-up with frequent re-evaluations. The exponential growth of echocardiography’s technology and performance in recent years has resulted in improved diagnostic accuracy, stratification, management and follow-up of patients with DCM. This review summarizes some new developments in echocardiography and their promising applications in DCM. Although nowadays cardiac magnetic resonance (CMR) remains the gold standard technique in DCM, the echocardiographic advances and novelties proposed in the manuscript, if properly integrated into clinical practice, could bring echocardiography closer to CMR in terms of accuracy and may certify ultrasound as the technique of choice in the follow-up of DCM patients. The application in DCM patients of novel echocardiographic techniques represents an interesting emergent research area for scholars in the near future.

Percutaneous Mitral Valve Annuloplasty in Patients With Secondary Mitral Regurgitation and Severe Left Ventricular Enlargement

OBJECTIVES

This study sought to determine the effect of percutaneous mitral valve annuloplasty with the Carillon device versus guideline-directed medical therapy (GDMT) alone in patients with secondary mitral regurgitation (MR) and severe left ventricular (LV) enlargement.

BACKGROUND

The clinical impact of the Carillon device in patients with severe LV dilation is not well established.

METHODS

This is a pooled analysis involving 3 prospective trials (TITAN [Transcatheter Implantation of Carillon Mitral Annuloplasty Device], TITAN II, and REDUCE FMR [CARILLON Mitral Contour System for Reducing Functional Mitral Regurgitation] trials) in which patients with functional MR and severe LV enlargement (LV end-diastolic diameter >65 mm) were treated with GDMT and the Carillon device versus GDMT alone. Key outcomes of this analysis were changes over 1 year of follow-up in mitral valve and LV echocardiographic parameters, functional outcome, quality of life, mortality, and heart failure hospitalization (HFH).

RESULTS

A total of 95 patients (67 in the Carillon group, 28 in the GDMT group) with severe LV enlargement were included. In the Carillon group, all mitral valve and LV morphology parameters were significantly improved at 1 year. Regurgitant volume decreased by 12 ml (p < 0.001), MR grade decreased by 0.6 U (p < 0.001), LV end-diastolic volume decreased by 25 cm3 (p = 0.005), and LV end-systolic volume decreased by 21 cm3 (p = 0.01). Significant functional improvement differences were also noted between the Carillon group and the GDMT group including an improvement of Kansas City Cardiomyopathy Questionnaire score (15 ± 4 vs. 6 ± 6; p = 0.03). The incidence of HFH was 29.9% versus 50.0% and the cumulative rate of HFH was 0.43 versus 0.75 (p < 0.001).

CONCLUSIONS

In patients with functional MR and severe LV enlargement, the Carillon device improved mitral valve function, LV morphology, and functional outcome compared with patients receiving GDMT only. Preoperative LV dimension should not be a limiting factor when evaluating patient eligibility or anticipated response to therapy with the Carillon device.