Mitral Regurgitation Mitral Valve Insufficiency

What Is Mitral Regurgitation?

Mitral regurgitation describes a disease of the heart. The heart valve's leakage is expressed as "-insufficiency." In contrast, heart valves can also develop stenoses, which describes a restricted valve opening.

The mitral valve is a leaflet located between the left atrium and the left ventricle. It allows blood from the atrium into the ventricle and prevents the reverse direction. The incomplete closure of the mitral valve causes blood to flow back from the left ventricle into the left atrium when the left ventricle contracts to eject the blood into the aorta.

Over time, this causes more blood to remain in the heart, resulting in left atrial dilation (left ventricular dilation). In severe forms of mitral regurgitation, enlargement of the left ventricle may also occur. This permanent volume load can often be compensated for a long time so that those affected do not notice any symptoms. The affected patients experience symptoms only when heart failure develops due to the permanent load.

Classification by Severity

Mitral valve regurgitation is classified according to the severity and based on its development into primary and secondary forms.

Severity is assessed by cardiac catheterization. A metal tube (catheter) is inserted via the groin into the leg artery under X-ray imaging and, from there, guided into the heart via the aorta. The contrast medium is then given from the tube in the left ventricle, which fills the left ventricle by diffusion and is visible on the X-ray screen. From this, it can be seen how much volume will flow back into the left atrium during the next heart contraction. The following degrees of severity are distinguished:

• Grade I: reflux volume less than 20%.
• Grade II: reflux volume 20-40%.
• Grade III: reflux volume 40-60%.
• Grade IV: reflux volume more significant than 60%

What Causes Mitral Valve Insufficiency?

Primary mitral regurgitation is caused by damage to the valve structures. This can have various causes; in Germany, degenerative changes are the most common. In most cases, the mitral valve loses its natural elasticity due to calcification and can no longer close completely.

Secondary mitral valve regurgitation is caused by a mismatch between the valve and the left ventricle. The mitral valve is structurally inconspicuous. The problem lies in the relation between the valve and the size of the left ventricle. If the left ventricle is too dilated, a gap remains open as the mitral valves close. Left ventricular dilatation, which causes the mismatch, results from chronic volume loading of the left ventricle. More volume than should stays in the left ventricle with each heartbeat when the amount of blood ejected (ejection fraction) is too low. This happens when the heart muscle has too little strength because it is undersupplied with oxygen, for example, in coronary artery disease or myocarditis. But increased resistance in the aorta due to calcification and high blood pressure can also reduce the ejection fraction.

A third cause is aortic valve stenosis and insufficiency, where the aortic valve does not properly close or open. The aortic valve separates the abdominal aorta from the left ventricle. If the aortic valve does not open properly, less blood can be expelled from the left ventricle than it should. If this valve is impaired in closing, blood flows from the aorta back into the left ventricle. Both lead to volume stress and, in the long term, to left ventricular dilatation.

What Are the Symptoms?

In chronic mitral regurgitation, symptoms appear late but rapid; severe progressions are possible in acute regurgitation.

• Extrasystole
• Shortness of breath
• Pulmonary edema
• Shock
• General decrease in performance and rapid fatigue

How Is Mitral Regurgitation Diagnosed?

If mitral regurgitation is suspected, the first step is to auscultate the heart with a stethoscope. The return flow of blood from the left ventricle into the left atrium is easily hearable through the stethoscope with about two finger widths below the left mamilla.

Doppler ultrasonography is particularly well suited for diagnosis because the anatomy can be imaged in motion, and the backflow of blood can be visualized. Furthermore, this inexpensive method is accessible to almost any physician and does not expose the patient to radiation.

An electrocardiogram (ECG) scan records the electrical activity of the heart and allows detection of an abnormal heartbeat or damage to the heart muscle.

During cardiac catheterization, the severity of mitral regurgitation can be determined by measuring the amount of blood that flows back from the left ventricle through the diseased mitral valve into the left atrium during each heartbeat.

Mitral Regurgitation Treatment

Treatment for chronic mitral regurgitation depends on the patient's symptoms. If no symptoms are present, patients with mild mitral regurgitation are advised to rest physically and treat the underlying disease. Regular monitoring of the general condition and ejection fraction is useful. Early surgical reconstruction of the valve or even valve replacement is advised if severe mitral regurgitation is present without symptoms.

Symptomatic patients with an ejection fraction > 30% are advised to undergo early surgical reconstruction or valve replacement. Surgery and medical therapy for heart failure are strongly recommended if the ejection fraction is < 30% and the patient is symptomatic.

Acute mitral regurgitation is an emergency and requires close monitoring, even in an intensive care unit if necessary. In addition, emergency mitral valve surgery is often needed.

When Is Mitral Valve Surgery Necessary?

All patients with severe mitral regurgitation are indicated for valve surgery. The operation of the first choice is a valve-preserving surgical mitral valve reconstruction. If valve reconstruction is impossible, does an artificial heart valve (biological or mechanical) have to be implanted? These two surgical methods are performed in open-heart surgery, where the heart is shut down, and a heart-lung machine takes over the heart's function for the duration of the surgery.

As a minimally invasive catheter-based procedure, the MitraClip is a new treatment option for patients with severe mitral regurgitation. In this procedure, a catheter is inserted through the groin and guided into the heart's left ventricle via the aorta. The mitral clip is then deployed and secured between the leaflets of the mitral valve. This method is used in Germany for patients with a high risk of surgery due to pre-existing or concomitant diseases or who are inoperable.

Which Physicians Are Specialists for Mitral Regurgitation Therapy in Germany and Switzerland?

Specialists in cardiology mainly treat mitral regurgitation. These physicians are responsible for the prevention, diagnosis, drug, and follow-up care. The MitraClip procedure also belongs to the field of cardiologists. On the other hand, open-heart surgery for conventional valve reconstruction and valve replacement falls under the area of cardiac surgeons.

We will help you find an expert for your condition. All listed physicians and clinics have been reviewed by us for their outstanding specialization in mitral regurgitation and are awaiting your inquiry or treatment request.

Sources:

Herold et al., Innere Medizin, Eigenverlag

Shah: Current concepts in mitral valve prolapse—Diagnosis and management. In: Journal of Cardiology. Band 56, Nummer 2, 2010, doi: 10.1016/j.jjcc.2010.06.004, S. 125–133.

Nkomo et al.: Burden of valvular heart diseases: a population-based study. In: The Lancet. Band 368, Nummer 9540, 2006, doi: 10.1016/s0140-6736(06)69208-8, S. 1005–1011.

Bonis et al.: Surgical and interventional management of mitral valve regurgitation: a position statement from the European Society of Cardiology Working Groups on Cardiovascular Surgery and Valvular Heart Disease. In: European Heart Journal. Band 37, Nummer 2, 2015, doi: 10.1093/eurheartj/ehv322, S. 133–139.