Mitral valve disease

The heart is an organ with four chambers: two atria and two ventricles. The atria receive blood from the vena cava and pulmonary veins and the ventricles push it through the aorta and pulmonary arteries. The cavities can contract, pushing the blood, and relax, allowing it to enter. The blood that comes through the veins, passes to the atria and from these, to the ventricles. Valves exist between the atria and ventricles to prevent backward flow of blood and blood flow in only one direction.

The four valves of the heart are:

• Aortic valve between the left ventricle and the aorta.
• Tricuspid valve between the right atrium and ventricle.
• Pulmonary valve between the right ventricle and the pulmonary artery.
• Mitral valve between the left atrium and ventricle.

An abnormality in any of the heart valves is called valvular disease. These can be of two types: stenosis or insufficiency.

Stenosis is an abnormal narrowing of the valve, which prevents it from opening properly which causes an obstruction of the blood outlet.

Insufficiency occurs when the valve is not working properly, is more weakened or bulged, and does not close completely, causing some of the blood to flow back when the valve should be fully closed.

The mitral valve can present any of these alterations: being narrower, which is known as mitral stenosis or not closing properly, which is known as mitral regurgitation.

Valvular heart disease is classified as mild, moderate, or severe (severe) depending on the degree of valve involvement and its impact.

How is it produced?

A valve disease can be congenital, that is, it can be present from birth or acquired, which is when it appears throughout life, for example, due to an infection. The most common infectious causes are endocarditis and rheumatic fever.

Currently, due to the longer life expectancy, a large part of valvular heart disease appears due to deterioration of the valve in the aging process (degeneration), which causes valvular hardening and calcification.

The most common causes of mitral valve disease are rheumatic fever and aging valve degeneration. It is very uncommon for it to be of congenital origin.

Another cause is infection of the valve (endocarditis), also trauma and myocardial infarction can damage it, leading to mitral regurgitation. Mitral valve prolapse is a disease characterized by a bulging of one or both leaflets that make up the mitral valve during contraction of the heart. This allows the blood to flow backward.

In mitral stenosis, there is a narrowing of the valve area that causes blood not to be able to pass from the atrium to the left ventricle, the accumulated blood generates an increase in pressure that causes the heart to fail and not have enough force to drive the blood forward. This can translate into the return of blood to the lung, giving symptoms such as shortness of breath and also that cardiac arrhythmias and embolisms appear easily.

In mitral regurgitation, since the valve does not close completely, when the left ventricle contracts, a part of the blood flows backwards, accumulating within the left atrium. This causes a progressive dilation of the heart that over time can lead to heart failure.

Symptoms or symptoms

The most common symptoms are dyspnea or a sensation of shortness of breath that increases with exercise and lying down (orthopnea) and the appearance of arrhythmias (the most common is atrial fibrillation). A serious complication of this valve disease is the appearance of embolisms due to the accumulation of blood and pooling in the atrium.

In mitral stenosis, patients may remain asymptomatic until the valve area is greatly reduced.

Mitral regurgitation can appear acutely, for example, by rupture of a tendon cord of the leaflets that make up the valve, typically after a myocardial infarction. In these cases the symptoms appear suddenly (mainly dyspnea).

Diagnosis

The diagnosis is based on the set of symptoms of the patient, the physical examination where a heart murmur is usually detected that indicates that there may be a valve disease.

Electrocardiogram recording can reveal left ventricular involvement due to valve disease.

Diagnostic confirmation is performed using imaging techniques that allow a detailed view of the morphology of the valve and its degree of involvement, as well as the consequences on the rest of the cardiac structures and blood flow.

These techniques mainly include:

• Doppler echocardiography: it is the technique of choice, it allows to see the degree of involvement of the valve and the rest of the cardiac structures, as well as the functioning of the blood flow through the heart chambers.
• Transesophageal echocardiography: This is the same procedure as echocardiography but the transducer is inserted into the patient's esophagus to see the heart valves in greater detail than with transthoracic echocardiography (where the transducer is applied to the chest).
• Magnetic resonance.
• Cardiac catheterization.

Treatment

In mild or moderate mitral stenosis, medical treatment is indicated aimed at alleviating the symptoms caused by the disease and its complications. They are used among other diuretics, anticoagulant and antiarrhythmic drugs.

Surgical treatment is reserved for those cases in which the stenosis is more severe, with significant symptoms and the valve area is greatly reduced. This consists of a valve repair or valve replacement.

In some patients with mitral stenosis, a nonsurgical procedure called balloon valvuloplasty may be performed in which a catheter (a hollow tube) is inserted into a blood vessel (usually from the groin) and threaded to the heart. The catheter, which contains a deflated balloon, is placed over the narrowed heart valve and inflated there to enlarge the valve opening.

In severe mitral regurgitation, treatment is surgical with repair (valvuloplasty) or valve replacement. Valve repair eliminates regurgitation or reduces it enough to make symptoms tolerable and to prevent heart damage. In the surgical treatment of valve replacement, biological valves (tissue) or mechanical valves that are made of synthetic materials are used.

Prevention

Streptococcal infections must be treated to prevent rheumatic fever that can cause heart valve disease.

Patients with valvular heart disease are at greater risk of valve infections (endocarditis), so they should follow preventive measures with antibiotics before certain procedures such as minor surgeries or dental interventions. Your doctor will advise you on the advice to follow.