Percutaneous mitral balloon commissurotomy
Synonyms and keywords: Balloon mitral valvuloplasty, PMBC, percutaneous mitral balloon valvotomy, percutaneous mitral balloon valvuloplasty, PMBV, mitral valvuloplasty, percutaneous mitral valvuloplasty, PMC, percutaneous mitral commissurotomy

# Overview
The safety and efficacy of PMBC have been shown compared with surgical closed or open commissurotomy in patients with a favorable valve morphology with less than 2+ mitral regurgitation and no evidence of left atrium thrombus. PMBC is performed by addressing one or more balloon catheters  across the mitral valve and inflating them, then splitting the commissures. Valve morphology including mobile and relatively thin valve leaflets, without calcium deposit, in the absence of significant subvalvular fusion are favorable for this procedure. An anatomic mitral morphology score can be used to determine suitability for PMBC and to evaluate the appearance of the commissures and degree of calcification. The outcome is also predicted by clinical factors including age, NYHA class, and presence or absence of atrial fibrillation. Older patients with lower gradients (<10 mm Hg) will not have a good outcome as patients with higher gradients, probably because of presence of other problems that cause symptoms, including LV diastolic dysfunction and LA noncompliance. PMBC  should be performed only by experienced Heart team, with surgical backup for potential complications. Reported long-term follow-up shown 70% to 80% of patients are free of recurrent symptoms after PMBC at 10 years, and 30% to 40% are free of recurrent symptoms at 20 years.

# Percutaneous Mitral Balloon Valvotomy (PMBV)
- PMBV is currently the standard of care in patients with severe rheumatic mitral stenosis and favorable valve anatomy.
- PMBV is preferred to open surgery in symptomatic moderate to severe MS, MVA 1.5 cm2, NYHA functional class 2-4, favorable valve anatomy, lack of commisural calcification, no or mild mitral regurgitation, and no left atrium thrombosis. 

# 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

## Recommendation for Nonrheumatic Calcific MS
Abbreviations:
PMC: Percutaneous mitral commissurotomy;
AF: Atrial fibrillation;
LA: Left atrium;
MVA:Mitral valve area ;
Abbreviations:
PMC: Percutaneous mitral commissurotomy;
MVA:Mitral valve area

## Indications
- Making decision on the type of treatment (PMBV or surgery), as well as its timing, is based on clinical characteristics, anatomy of valve and subvalvular apparatus, and local expertise.
- Intervention is indicated in patients with moderate-to-severe rheumatic mitral stenosis (valve area 1.5 cm2) in whom PMC has had a significant impact on its management.
- In Western countries, the incidence of rheumatic fever  and number of PMBV is low. Howerer, over the years PBMV has been as a mainstay therapy, especially in developing countries with endemic rheumatic heart disease.
- Indications for PMBV have expanded to involve less suitable conditions including suboptimal valve anatomy and also palliative therapy in elderly patients who are poor surgical candidates.
- The cost of intervention is lower than mitral valve replacement surgery.
- To determine which patients would benefit from Percutaneous mitral balloon valvotomy (PMBV), a scoring system has been developed. Scoring is based on four echocardiographic criteria:
- Leaflet mobility
- Leaflet thickening
- Subvalvar thickening
- Calcification
- Individuals with a score of  8 tended to have suboptimal results. Superb results with valvotomy are seen in individuals with a crisp opening snap, score < 8, and no calcium in the commissures.
- The new onset of atrial fibrillation (AF) may indicate proceeding with PMBC in the asymptomatic patient with a favorable valve morphology as follow:
- AF may be indicative of symptom onset, and progressive left atrium damage
- AF increases the risk of thromboembolic events in patients with rheumatic mitral stenosis.
- A shortened diastolic filling interval with AF and a rapid ventricular response further increase LV pressure.
- The presence of AF is associated with worse outcomes in patients with rheumatic mitral stenosis and with suboptimal results after PMBC.
- Lowering a high LA pressure after PMBC might be beneficial in restoring normal sinus rhythm.

## Contraindications for percutaneous mitral commissurotomy in rheumatic mitral stenosis
- Persistent Left atrial or left atrial appendage thrombus
- More than moderate mitral regurgitation
- Massive or bi-commissural calcification
- Absence of commissural fusion
- Severe concomitant aortic valve disease, or severe  organic tricuspid stenosis or severe functional tricuspid regurgitation  with enlarged annulus
- Severe concomitant coronary artery disease  requiring bypass surgery

## Technique
The interventional cardiologist gains access to the mitral valve by making a puncture in the interatrial septum during cardiac catheterization.
- Inflation and rapid deflation of a single balloon or a double-balloon opens the stenotic valve. This mechanism is similar to that of surgical commissurotomy.
- Transvenous transeptal technique is most commonly used with the Inoue balloon system.
- Fossa ovalis lies usually at 1-7 oclock but this orientation can be distorted in the presence of mitral stenosis where the interatrial septum becomes more flat, horizontal, and lower.
- For the femoral vein approach a 70 cm Brockenbrough needle should be used or an 8 Fr Mullins sheath and advanced under fluoroscopic guidance with pressure monitoring.
- The latter is necessary to monitor for punctures into adjacent structures such as the aorta.
- Further catheter manipulation may be necessary to direct the catheter into the left ventricle through the mitral valve rather than towards one of the pulmonary veins.
- The Mullins sheath is exchanged for a solid-core coiled 0.025-inch guidewire over which a 14 Fr dilator is placed.
- This is exchanged for the Inoue balloon (24-30 mm) which inflates in three stages allowing for balloon self-positioning with the last inflation resulting in commissural splitting.
- A transthoracic echocardiography should be done to measure the mitral valve area and assess the severity of regurgitation as a complication of the procedure.
- PMBV should be stopped if adequate valve area has been achieved or if the severity of mitral regurgitation has been increased.

## Outcome
- Long-term follow-up has been shown an initial good result and free of recurrent symptoms in 70% to 80% of patients after PMBC at 10 years, and 30% to 40% are free of recurrent symptoms at 20 years.

### Complications
- Cerebral accident (0.5-1%)
- Mitral regurgitation requiring surgery (1.6-3%)
- Mortality (0-0.5%)