The mitral valve lies in between the left atrium and left ventricle. When the mitral valve opens, blood from the left atrium flows into the left ventricle. Once the blood in the left atrium is emptied, the mitral valve closes, following which the left ventricle ejects blood through the aorta to the rest of the body.
The flow of blood has to happen in one direction alone as described above. However, in certain cases, the blood flows back up from the ventricle to the atrium through a faulty mitral valve. This backward flow of blood, or ‘leak’, is called mitral regurgitation (or mitral valve regurgitation).
Here we take a look at this condition in a little more detail.[toc]
What is mitral valve regurgitation?
Mitral regurgitation is a clinical condition where the blood leaks back through the mitral valve every time the left ventricle contracts. As explained previously, the mitral valve should only allow flow of blood from the atrium to the ventricle.
However, in certain situations, blood can flow back from the ventricle into the atrium. The amount of blood that flows back can range from trivial all the way to a large amount of blood.
What are the causes of mitral regurgitation?
Broadly classified, mitral regurgitation can be primary mitral regurgitation or secondary mitral regurgitation. In primary mitral regurgitation, the basic problem lies in the structure of the valve. In secondary mitral regurgitation, the problem lies with the way the left ventricle works.
Below is a list of common causes of mitral regurgitation –
- Mitral valve prolapse
This is an extremely common condition in India and is often the cause of mitral regurgitation. Here, the mitral valve leaflets are broadly supported by the different structures that control the movement of the mitral valve. Due to this, a small part of the mitral valve leaflet bulges back into the atrium every time the left ventricle contracts. When this happens, a small gap is created between the leaflets through which the blood leaks back into the atrium.
- Rheumatic fever
This is yet another common cause of mitral regurgitation. Rheumatic fever is a condition where the valves are affected following an infection in the throat. It often occurs in childhood that presents later in adult hood. If rheumatic fever affects the mitral valve significantly, the degree of mitral regurgitation can be severe.
- Damage to chordae tendinae
These are thin tendon like structures that are attached to the tip of the mitral leaflets. Any injury to these structures from either trauma or excessive stretching can result in mitral regurgitation.
- Birth defects
Birth defects that affect the mitral valve are rare but are recognised in clinical practice.
- Drugs and medications
This is another rare cause of mitral regurgitation. Prolonged use of drugs that are used in the treatment of migraine may sometimes lead to mitral regurgitation.
- Following radiation therapy
Radiation therapy is often a part of treatment regimens for cancer. If the heart is inadvertently exposed to radiation, patients may develop mitral regurgitation.
- Advancing age
It is not uncommon as age advances for the mitral valve leaflets to function in adequately. Often this results in only trivial mitral regurgitation that is of no significance.
What are the clinical symptoms of mitral regurgitation?
Patients who have trivial to mild regurgitation often do not have any symptoms. Even individuals who have moderate to severe mitral regurgitation do not have symptoms in the early stages. However, as the duration of the illness progresses, patients may start to notice some of the clinical symptoms that have been listed below –
- Breathing difficulty
Patients may become slightly short of breath when they walk on a flat surface or up a slight incline. This will feel unusual to them. In more severe cases, patients may become breathless at rest and even when they lie down in bed.
This is a very common symptom that patients who have moderate to severe mitral regurgitation experience. The fatigue is often on exertion and patients may find themselves sleeping most of the day.
Fatigue can be more pronounced in patients who have reduced function of the left ventricle.
Palpitations are a subjective experience of thumping of the heart in the chest. Patients who have mitral regurgitation can sometimes have an irregular heartbeat or might have a hard that pumps harder than usual. Some individuals experience this as palpitations.
A common rhythm abnormalities in that is noticed in patients with mitral regurgitation is atrial fibrillation.
- Swelling in the ankles and the feet
This symptom is common in those in whom the function of the left ventricle is compromised. The feet can become quite heavy and when pressing the skin a small dent is created due to the displacement of fluid underneath it.
The above symptoms are commonly seen in patients who have had mitral regurgitation for a number of years and in whom it has been progressing gradually over that period. This type of mitral regurgitation is called as chronic mitral valve regurgitation. However, there are certain cases where mitral regurgitation can be sudden and can significantly impact a patient’s life. This is known as acute mitral valve regurgitation.
Acute mitral valve regurgitation
Acute mitral regurgitation is an uncommon clinical emergency that requires hospitalisation and aggressive treatment. It is often secondary to a heart attack.
Patients who develop acute mitral regurgitation can become extremely tired, have a fast heart rate, accumulate fluid in the lungs and can become short of breath. Confusion and chest pain are other symptoms.
Diagnosis and treatment
Patients who suffer from mitral regurgitation may not experience any symptoms in the early stages. However, as the condition progresses, the above symptoms may start to appear.
Diagnosis is usually made when the doctor has a listen to the patient’s heart with a stethoscope. A heart murmur is audible on examination and this can be timed by the doctor.
A confirmatory diagnosis of mitral valve regurgitation can be made through echocardiography. An echocardiogram is an ultrasound test which can help the doctor visualise the structure of the heart muscle including the valves. In mitral regurgitation, the structure of the mitral valve, how it opens and closes, the quantity of blood leakage and the function of the left ventricle will be particularly looked at.
An ECG may be performed as well in certain cases especially if a specific underlying cause is being considered.
Individuals who have chronic mitral regurgitation may have an enlarged heart which can be seen on a chest x-ray.
A coronary angiogram may be performed if the mitral valve regurgitation is severe enough to require surgical correction. A coronary angiogram will help determine if there are any narrowing in the heart arteries which may need to be treated when the mitral valve is being operated upon. In other words, if there is narrowing of the arteries, patients may require a coronary artery bypass graft surgery along with the mitral valve surgery.
Complications of mitral regurgitation
Complications are mitral regurgitation are well recognised but are not very common as treatment is now started sooner rather than later. Some of the common complications that may be associated with mitral valve regurgitation include –
- Heart failure – Here the pumping action of the left ventricle is compromised.
- Atrial fibrillation – This is an irregular heart rhythm that is caused by enlargement of the left atrium due to the constant inflow of blood through the mitral valve.
- Infective endocarditis – This is a condition where there is a bacterial infection of the mitral valve leaflets. This is a serious condition and requires hospitalisation and a long course of antibiotic therapy.
What is the treatment of mitral valve regurgitation?
The treatment of mitral regurgitation depends upon the severity of the condition. If you suffer from chronic mitral regurgitation that is mild on clinical examination and on echocardiography, often no treatment is required. In such patients a ‘wait and watch policy’ is followed.
However, if patients have a moderate to severe degree of mitral regurgitation and are experiencing any of the symptoms listed above, medical therapy along with possible surgical correction may be required.
as blood is flowing back from the ventricle into the atrium, it does cause a great deal of overload of the atrium. In order to reduce this overload, tablets called diuretics are prescribed. Diuretics and medications that can prevent the accumulation of fluid in the body and in mitral regurgitation they can help control breathlessness that arises from accumulation of fluid in the lungs. The commonly used diuretics include Frusemide, Aldactone and Metolazone.
If you suffer from atrial fibrillation as well, blood thinning medication such as Acetrom or Warfarin may be required.
Control of blood pressure is extremely important in patients with mitral regurgitation. Following a low salt diet and taking antihypertensive medications as prescribed by the Doctor is strongly recommended.
These days, surgery is offered sooner rather than later for patients before complications occur and irreversible symptoms set in. However, the decision regarding when it is right to operate is made by the treating physician in conjunction with the patient’s wishes. Many a time, surgery is postponed until early signs of heart failure are noticed.
There are two ways that mitral valve regurgitation can be treated surgically – mitral valve repair and mitral valve replacement.
Mitral valve repair
As the name suggests, in mitral valve repair the leaflets of the mitral valve is surgically repaired so that they close normally and do not allow blood to leak back into the left atrium. Any excessive valve tissue is removed and the valve is reshaped so that the leaflets close tightly when the valve shuts.
Often patients who undergo mitral valve repair require strengthening of the ring that forms the outer aspect of the mitral valve. This ring is called the annulus and the surgery is called annuloplasty. The valve may be very attached to the chordae tendinae (this is called chordal transposition).
Mitral valve repair is often referred as a treatment strategy over mitral valve surgery these days (unless the valve is not amenable to repair).
Techniques of mitral valve repair
With advancing technology, it is noe possible to repair the mitral valve through minimally invasive methods without requiring open heart surgery. New technologies such as robot assisted heart surgery, ministernotomy and thoracoscopy-assisted surgeries are now being performed in various specialist centers across the country.
In robot assisted heart surgeries, specialised robotic arms are controlled by a surgeon who visualizes the structure of the heart on a 3-D viewer. The procedure is extremely accurate and has very good results.
Minimally invasive surgical repair of the mitral valve leaflets can be performed through a small incision made on the breast bone. This is called mini-sternotomy.
Other than the above, sometimes specialised it catheters (long tubes) may be used to repair the mitral valve. This is usually a strategy that is adopted if a mitral valve that has been previously repaired or replaced requires correction function. For example, a bioprosthetic valve that is functioning improperly can be replaced by a new valve using catheters only.
Mitral valve replacement surgery
Here, the entire mitral valve is removed and is replaced with an artificial valve. The artificial valve either by a mechanical valve (made of metal) or a bioprosthetic valve (made of a valve derived from pigs).
Mechanical valves run the risk of forming blood clots on their surface. For this reason, patients may require blood thinners such as warfarin or Acetrom to prevent the blood from clotting.
If you suffer from mitral regurgitation, there are certain lifestyle changes that you may have to make to prevent progression and complications. Some of the important ones are listed below –
- Keep your salt intake low – a high salt intake is directly linked to high blood pressure which can be problematic if you have mitral regurgitation. Make sure that you eat foods that are low in salt and avoid processed foods such as pickles, papads, ready soups and cheeses.
- Exercise regularly – exercise forms an important part of treatment. However, we recommend that you get the all clear from your Doctor before taking up any sort of exercise plan. In a nutshell, individuals who have mild to moderate mitral valve regurgitation without any symptoms can usually perform most exercises without any hindrance. However, those who have heart failure or an irregular heartbeat may need to limit their activity to an extent. Regular walking is often not a problem but brisk walking may not be recommended by your Doctor. Make sure you speak to your physician regarding what is safe and what you can and cannot do.Weight training is not recommended.
- Maintain dental hygiene – Infections of the teeth or poor dental hygiene can sometimes cause bacteria to enter the bloodstream and infect the heart valve. This is a cause of infective endocarditis of the mitral valve. Make sure you visit your dentist regularly and maintain good oral health. If you have to undergo any dental surgeries, you may require a short course of antibiotics to prevent infection of the valve (though this recommendation seems to have changed in the recent years). Your dentist and physician will guide you regarding what antibiotics to take and whether or not it is really required.