Echocardiographic Assessment of Mitral Stenosis

Rheumatic and Degenerative Mitral Stenosis: From an Iconic Clinical Case to the Literature Review

Mitral stenosis (MS) poses significant challenges in diagnosis and management due to its varied etiologies, such as rheumatic mitral stenosis (RMS) and degenerative mitral stenosis (DMS). While rheumatic fever-induced RMS has declined in prevalence, DMS is rising with aging populations and comorbidities. Starting from a complex clinical case of DMS, the aim of this paper is to review the literature on mitral stenosis by analyzing the available tools and the differences in terms of diagnosis and treatment for rheumatic and degenerative stenosis. Emerging transcatheter techniques, such as transcatheter mitral valve replacement (TMVR) and lithotripsy-facilitated percutaneous mitral commissurotomy (PMC), represent promising alternatives for DMS patients deemed unfit for surgery. In particular, intravascular lithotripsy (IVL) has shown potential in facilitating percutaneous interventions by fracturing calcific deposits and enabling subsequent interventions. However, larger prospective studies are warranted to validate these findings and establish IVL's role in DMS management. To further enhance this technique, research could focus on investigating the long-term outcomes and durability of mitral lithotripsy, as well as exploring its potential in combination with PMC or TMVR.

Yeo's index: A novel index that combines anatomic and haemodynamic assessment of the severity of mitral stenosis

BACKGROUND

A mitral leaflet separation index (MLSI), measuring the anatomical separation of the mitral valve (MV) leaflet tips in diastole, was previously described as an accurate method of assessing mitral stenosis (MS). We propose a novel modification of the MLSI by including a hemodynamic assessment which we term Yeo's index that may improve its diagnostic performance.

METHODS AND RESULTS

We retrospectively studied 174 patients with varying severity of MS without significant mitral regurgitation, aortic valve disease or ventricular septal defect. MLSI was measured in 2 orthogonal views on transthoracic echocardiography as previously described. MV dimensionless index (DI) was calculated by dividing the left ventricular outflow tract pulsed-wave Doppler time velocity integral (TVI) by the MV continuous-wave Doppler TVI. We defined Yeo's index as the product of MLSI and DI. With linear correlation, Yeo's index demonstrated good correlation against MVA by planimetry (r = 0.728), pressure half-time (r = 0.677), and continuity equation (r = 0.829), with improved performance over the MLSI. Using ROC analysis, Yeo's index demonstrated good ability to correctly classify MS as severe (MVA ≤1.5cm2) (AUC 0.874, 95% CI 0.816-0.920). Yeo's index ≤0.260 cm correctly classified severe MS with sensitivity of 82% and specificity of 80%. Presence of AF did not affect the performance of Yeo's index. Yeo's index ≤0.147 cm also identified very severe MS (MVA ≤ 1.0 cm2) with specificity of 94% and sensitivity of 78%.

CONCLUSION

Yeo's index performed well in identifying severe MS and may be a useful adjunct to existing measures of MS severity.

Management of mitral stenosis: a systematic review of clinical practice guidelines and recommendations

A number of guidelines exist with recommendations for diagnosis and management of mitral stenosis (MS). We systematically reviewed existing guidelines for diagnosis and management of MS, highlighting their similarities and differences, in order to guide clinical decision-making. We searched national and international guidelines in MEDLINE and EMBASE (5/4/2011-5/9/2021), the Guidelines International Network, Guideline Library, National Guideline Clearinghouse, National Library for Health Guidelines Finder, Canadian Medical Association Clinical Practice Guidelines Infobase, and websites of relevant organizations. Two independent reviewers screened titles and abstracts, and the full text of potentially relevant articles where needed. Selected guidelines were assessed for rigor of development; only guidelines with Appraisal of Guidelines for Research and Evaluation II instrument score >50% were included in the final analysis. Four guidelines were retained for analysis. There was consensus for percutaneous mitral balloon commissurotomy as first-line treatment of symptomatic severe rheumatic MS with suitable anatomy. In patients with unfavourable anatomy, surgical intervention should be considered. Exercise testing is indicated if discrepancy exists between symptoms and echocardiographic measurements. There was no clear divide between rheumatic MS and degenerative MS for their respective diagnoses and management. Pregnancy in severe MS is discouraged and the stenosis should be treated before conception. Long-term antibiotic prophylaxis is recommended for patients with rheumatic MS. Recommendations for the management of patients with mixed valvular diseases are lacking.

Clinical and Hemodynamic Factors Associated with Low Gradient Severe Rheumatic Mitral Stenosis

Discrepancy between narrowed mitral valve area and transmitral gradient is not uncommon, suggesting the presence of low gradient (LG)-severe mitral stenosis (MS). Some clinical and hemodynamic factors are believed to associate with LG-severe MS. Transthoracic echocardiography reports were reviewed retrospectively to evaluate the association of all clinical and hemodynamic parameters with LG-severe MS. A 36% of total 322 patients was in the LG-severe MS group. In multivariate analysis, atrial fibrillation (95% confidence interval [CI] 4.60-16.71, odds ratio [OR] 8.77), net atrioventricular compliance > 4 mL/mm Hg (95% CI 3.96-14.25, OR 7.51), tricuspid regurgitation maximal velocity (TR Vmax) > 3.4 m/s (95% CI 0.13-0.48, OR 0.25), stroke volume index ≤ 35 mL/m ² (95% CI 1.49-6.25, OR 3.05), female gender (95% CI 1.30-5.33, OR 2.63), and severe tricuspid regurgitation (95% CI 1.04-5.50, OR 2.39) were found to be associated with LG-severe MS. Atrial fibrillation, net atrioventricular compliance, TR Vmax, stroke volume index, female gender, and severe TR were associated with low transmitral gradient in patients with severe MS.

[Rheumatic mitral aggression. Usefulness of 3d transesophageal echocardiography]

Rheumatic heart disease is the leading cause of cardiovascular disease in children under 25 years of age worldwide, with the highest prevalence in low-income countries. The usual and distinctive finding of rheumatic aggression is mitral stenosis, which leads to serious cardiovascular consequences. International guidelines establish transthoracic echocardiography (TTE) as the diagnostic test for rheumatic heart disease; however, it has limitations in the measurement of planimetry and those inherent to Doppler. Transesophageal 3D echocardiography (TTE-3D) is a new modality that shows realistic images of the mitral valve and has the added value of accurately locating the plane of maximum stenosis and better determining commissural involvement.

Advances in Rheumatic Mitral Stenosis: Echocardiographic, Pathophysiologic, and Hemodynamic Considerations

Echocardiography is the primary imaging modality used in patients with mitral stenosis. Doppler-derived measurements of mitral pressure half-time are commonly used to calculate mitral valve area, but a number of hemodynamic confounders associated with advanced age limit its utility. Planimetry remains the gold standard for determining mitral valve area and may be performed using two- or three-dimensional imaging. Although the Wilkins score has been used for >30 years to predict balloon mitral valvuloplasty outcomes, newer scoring systems have been proposed to improve predictive accuracy. Some patients undergoing technically successful balloon mitral valvuloplasty may not have satisfactory clinical outcomes. These individuals may be identified by the presence of reduced net atrioventricular compliance, which can be measured echocardiographically. Exercise testing may be useful in patients with mitral stenosis whose symptomatic status is incongruous their mitral valve area. Last, reduced left atrial systolic strain, an indicator of poor left atrial compliance, has been shown to reliably predict adverse outcomes in patients with mitral stenosis. The author discusses the hemodynamics and path ophysiology of mitral stenosis and reviews current and emerging roles of echocardiography in its evaluation.

Cardiovascular imaging modalities in the diagnosis and management of rheumatic heart disease

Rheumatic heart disease (RHD) is prevalent in sub-Saharan Africa, where the capacity for diagnosis and evaluation of disease severity and complications is not always optimal. While the medical history and physical examination are important in the assessment of patients suspected to have RHD, cardiovascular imaging techniques are useful for confirmation of the diagnosis. Echocardiography is the workhorse modality for initial evaluation and diagnosis of RHD. Cardiovascular magnetic resonance is complementary and may provide additive information, including tissue characteristics, where echocardiography is inadequate or non-diagnostic. There is emerging evidence on the role of computed tomography, particularly following valve replacement surgery, in the monitoring and management of RHD. This article summarises the techniques used in imaging RHD patients, considers the evidence base for their utility, discusses their limitations and recognises the clinical contexts in which indications and imaging with various modalities are expanding.

Degenerative mitral valve stenosis: Diagnosis and management

Mitral stenosis (MS) is a common valvular disease characterized by narrowing of the mitral valve orifice and a reduction in mitral valve area (MVA). While rheumatic MS (RMS) is frequently encountered in young individuals in developing countries, degenerative MS (DMS) is seen in the elderly in developed countries and its prevalence is increasing. DMS is usually a late presentation of mitral annular calcification (MAC). Accurate assessment of MVA in patients with MAC is challenging due to the alterations in the atrial and valvular structures as well as the presence of other comorbidities in this aging population. We will review the epidemiology, etiology, pathophysiology, diagnostic assessment, and management of DMS and compare the findings with RMS. The latest therapeutic approaches, including medical, surgical, and transcatheter valvular interventions, will be discussed.

Interventional Echocardiography of the MV: What the Interventionalist Wants to Know

The past 2 decades have seen a proliferation of transcatheter mitral valve (MV) therapies, which are less invasive and distinct from surgical MV repair or replacement. The commonly used MV transcatheter therapies include (1) percutaneous mitral balloon commissurotomy (PMBC) for rheumatic mitral stenosis; (2) edge-to-edge repair with the MitraClip for mitral regurgitation; (3) valve-in-valve implantation in bioprosthetic MV, native MV, or mitral ring; and (4) closure of paravalvular leaks (PVLs). This article will focus on the use of echocardiography in the diagnosis, patient selection, procedural guidance, and postprocedural follow-up for PMBC, with notes on the role of transesophageal echocardiography in transcatheter interventions for prosthetic valve degeneration and PVL closure.

Standard transthoracic echocardiography and transesophageal echocardiography views of mitral pathology that every surgeon should know

The mitral valve is the most commonly diseased heart valve and the prevalence of mitral valve disease increases proportionally with age. Echocardiography is the primary diagnostic imaging modality used in the assessment of patients with mitral valve disease. It is a noninvasive method which provides accurate anatomic and functional information regarding the mitral valve and can identify the mechanism of mitral valve pathology. This is especially useful as it may guide surgical repair. This is increasingly relevant given the growing trend of patients undergoing mitral valve repair. Collaboration between cardiac surgeons and echocardiographers is critical in the evaluation of mitral valve disease and for identification of complex valvular lesions that require advanced surgical skill to repair. This article will provide an overview of transthoracic and transesophageal assessment of common mitral valve pathology that aims to aid surgical decision making.