What is a mitral commissurotomy?
The mitral valve is the valve between the upper and lower chambers on the left side of the heart. After rheumatic fever, the two leaflets of this valve can become stuck together at their edges, so that the opening narrows (mitral stenosis) and blood cannot pass easily from the lungs into the heart. A balloon mitral commissurotomy, also called balloon valvuloplasty, opens that narrowing without surgery: a balloon is guided into the valve and inflated so that the fused edges split apart and the valve opens more widely.
Why is it done?
It is offered to patients with significant rheumatic mitral stenosis who are breathless, tire easily, cough up blood or have developed abnormal heart rhythms or raised pressure in the lung arteries. Opening the valve relieves these symptoms, often dramatically, and avoids or postpones open heart surgery. It is also used in pregnancy, when a narrowed valve becomes dangerous, because it avoids the risks of surgery to mother and baby.
Who is suitable?
Not every narrowed mitral valve can be treated this way. A detailed ultrasound of the heart, usually including one done via the gullet, is performed first to check the shape of the valve, how much scarring there is, whether the valve also leaks, and whether a blood clot is present in the upper chamber. If the valve is heavily damaged or leaking badly, open heart surgery is the better option.
What happens on the day?
The procedure is done in the catheterisation laboratory. The skin over a vein in the groin is numbed with local anaesthetic and you will be given a general anaesthetic. A catheter is passed up the vein to the right side of the heart, a small, controlled opening is made in the wall between the two upper chambers so that the left side can be reached and a special balloon is guided across the narrowed valve. The balloon is inflated for a few seconds, sometimes more than once, to increase the size of the narrowed valve.
What to expect afterwards
You lie flat for several hours so that the groin puncture seals, and your heart rhythm and blood pressure are watched. Many patients notice easier breathing within days. Most people go home the next day.
Possible complications
Most patients do well, but there are real risks. Bruising or bleeding at the groin is the most common. The valve may end up leaking, and if the leak is severe, urgent open heart surgery to replace the valve may be needed - this happens in a small percentage of cases. Other uncommon problems are a persistent hole in the wall between the upper chambers, bleeding around the heart requiring drainage, stroke caused by a clot travelling to the brain, a disturbance of heart rhythm or an incompletely opened valve requiring further treatment.
This information does not replace a consultation. Please discuss your own risks and options with your cardiologist.