What is Mitral Stenosis?

The mitral valve leaflets stiffen and become immobile in mitral stenosis (MS), which prevents blood from flowing from the left atrium to the left ventricle. Pressure builds up inside the left atrium, pulmonary vasculature, and right heart because of mechanical obstruction. The mitral valve is affected by the rheumatic disease in most MS cases. As the disease advances, the mitral valve apparatus experiences several pathologic changes that are indicative of rheumatic valve disease, including the fusing of the leaflet commissures and the thickening, fusion, and shortening of the chordae tendineae. Another cause of mitral stenosis that is becoming more widely recognised is degenerative mitral annular calcification. Patients with mitral stenosis caused by degenerative mitral annular calcification are older and frequently have concurrent left ventricular diastolic dysfunction and left atrial noncompliance, in contrast to younger patients with mitral stenosis attributable to rheumatic heart disease.

MS is typically a progressive condition if the stenotic lesion is not treated. In asymptomatic people, progression is gradual; however, once symptoms start, it moves more quickly. Geographical differences in MS progression rates exist. Before exertional dyspnea may be linked to MS, a valve area of at least 2.5 cm ² must be present; a valve size of just 1.5 cm² is often needed to cause symptoms while at rest. In asymptomatic patients, atrial fibrillation frequently acts as the initial symptom-producing factor

Stages of Mitral Stenosis

There are four stages of MS: at risk of MS, progressive MS, asymptomatic severe MS, and symptomatic severe MS. Regarding severe symptomatic MS, anatomical changes of the valve are changes with commissural fusion and diastolic doming of the mitral valve leaflets. Planimeter MVA (Mitral Valve Area) is ≤1.5 cm2. Haemodynamic consequences are Severe LA enlargement and elevated PASP (Pulmonary Arterial Systolic Pressure) >30 mmHg. Decreased exercise tolerance and exertional dyspnea are some of the symptoms of patients with severe symptomatic MS

Treatments for severe MS

The decision between percutaneous and surgical mitral valve (MV) operations for MS patients with an indication for intervention is influenced by local competence and the availability of interventional and surgical techniques. PMBV is favoured to open mitral commissurotomy in patients with rheumatic MS who have characteristics that lend themselves to percutaneous mitral balloon valvotomy (PMBV).

In the following cases, surgery is preferred. Because the anatomy is complicated, the value of PMBV may be restricted, and catheterization techniques are potentially risky in individuals with congenital MS, surgery is frequently preferred. Patients with rheumatic MS who have adequate valve morphology but are not candidates for PMBV due to valve deformity or calcification left atrial thrombus, or severe mitral regurgitation should consider open commissurotomy. Closed commissurotomy is not advised in places when PMBV or open MV surgery is accessible, however, it is still used in resource-constrained settings. MV replacement is recommended for operable patients with MS who have an MV that is not responsive to PMBV or open commissurotomy. You can refer to an article which gives more information on this using this link

MS caused by significant mitral annular calcification (MAC) is not treatable with PMBV and has a high morbidity and death rate when treated with surgical MV replacement. Transcatheter Mitral Valve Replacement (TMVR) is an investigational treatment for MS caused by severe MAC that requires additional research. Nowadays, valve replacement procedures are performed all around the world, and one such place is Heart Valve Experts which performs TMVR in Mumbai/India. You can also follow the Facebook pages: Heart Valve Experts, and Heart Valve Surgery If you are interested in recent updates on similar topics.

In Summary,

There are plenty of treatment options for severe MS in the current context and among them, treatment modalities like TMVR are on the rise.

References

1. Pathophysiology and natural history of mitral stenosis – UpToDate. Accessed August 3, 2022. https://www.uptodate.com/contents/pathophysiology-and-natural-history-of-mitral-stenosis
2. Rheumatic mitral stenosis: Overview of management – UpToDate. Accessed August 3, 2022. https://www.uptodate.com/contents/rheumatic-mitral-stenosis-overview-of-management
3. Surgical and investigational approaches to the management of mitral stenosis – UpToDate. Accessed August 3, 2022. https://www.uptodate.com/contents/surgical-and-investigational-approaches-to-management-of-mitral-stenosis