Balloon Mitral Valvuloplasty (BMV)
What is BMV?
BMV is the treatment for Mitral valve Stenosis, which is caused mainly due to rheumatic fever and rheumatic heart disease. Stenosis means abnormal narrowing. The mitral valve is located in the heart between the left atrium and left ventricle. When the mitral valve becomes narrow BMV can be done in the catheterization laboratory where a balloon is inserted via a thin tube through an artery in the groin area (upper thigh). The balloon is inflated in the mitral valve which helps increase the flow of blood in the heart by widening the opening.
Rheumatic mitral valve stenosis:
Previously, rheumatic mitral valve stenosis was very common in India. Unlike in the past, Rheumatic mitral stenosis is now relatively uncommon in children and adolescents.
Usually untreated bacterial infection with group A Streptococcus bacteria may lead to rheumatic fever which affects the mitral valve in the heart, leading to the development of mitral regurgitation (leaky valve). As the disease progresses, thickening and calcification of the mitral valve occurs, causing gradual fibrosis and stenosis of the mitral valve. Patients with mitral valve stenosis show symptoms such as gradual onset of shortness of breath on exertion due to increase in the pressure inside the left upper chamber of the heart (left atria). As the disease condition worsens, patients may be unable to sleep at night.
Who can undergo a BMV?
The following criteria must be fulfilled:
There should be none or at most minimal leakage in the valve
There should be no calcium deposit on the valve
There should be no clots in the left atrium. This is usually identified prior to procedure by echocardiography. In some instances a trans esophageal echo (TEE) may be needed
Prior to a BMV the cardiologist usually performs a careful echo and is able to predict the likelihood of a good result.
Advantages of Balloon mitral valvuloplasty:
In those patients with pure mitral stenosis and with no calcium deposits it is the preferred alternative to open heart surgery. The procedure is relatively simple, avoids the trauma of surgery and allows discharge in a few days. Following the procedure, it may not be necessary to administer medications to prevent blood clotting (oral anticoagulants or blood thinners), particularly if the patients are having a regular heart rhythm. The benefits of the procedure may last several years and may allow the opportunity for young female adults to complete their family. Eventually, the ballooned valve may become narrow again and a mitral valve replacement with a mechanical valve may be eventually required.
Complications of BMV:
There is a small risk associated with BMV, like any invasive procedure in the cath lab. This includes damage to mitral valve leaflets with variable degrees of leakage or mitral regurgitation (MR). If this leak is severe, there may be a need for emergency valve replacement operation. In expert hands, the risk of severe leakage or MR is 1-2%
Stroke may happen under exceptional circumstances because of dislodgement of undetected clots in the left atrium during the procedure. This is prevented by careful assessment by echocardiography prior to the procedure
Bleeding in the space around the heart (pericardial tamponade) can occur as a consequence of one of the steps of the BMV procedure in which the needle is used to puncture the atrial septum. This is very rare (<1%) in the hands of experienced operators.
Long term expectations:
BMV results in benefits that typically last 5-10 years. The results are dictated by two factors:
Suitability of the valve for the procedure. Some valves open better than others and the benefit lasts long.
The adherence to penicillin. It is vital to continue taking penicillin to prevent the recurrence of rheumatic fever. The best method of taking penicillin in these patients is injections of benzathine penicillin (Penidura or longacillin) every 3 weeks.
It is imperative to maintain regular follow-up after the procedure to monitor the condition of the valve after BMV.