Overview

The heart is the main organ in the cardiovascular system that pumps blood throughout the body, helps bring oxygen and nutrients into the cells, and collects waste and carbon dioxide to be passed on to other organs to be filtered and disposed of. There are 4 valves in the heart: aortic valve, mitral valve, tricuspid valve, and pulmonary valve.¹

Heart valves are like doors, that ensure that the blood flows in the proper direction and prevent it from flowing backwards. The mitral valve lets oxygen-rich blood from the lungs flow from the left atrium to the left ventricle and other body parts.  Mitral valve disease is a group of conditions affecting the mitral valve that can be acquired (develops over time) or congenital (condition present during birth). According to the severity of the condition affecting the valve, it can lead to grave conditions like heart failure that are often treatable.

Mitral valve disease

Mitral valve disease affects the valves between the left atrium and left ventricle. The different forms of mitral valve disease are: 

Mitral valve stenosis

Mitral stenosis is the condition where the valve narrows. This condition reduces or blocks the blood flow into the left ventricle. Over time, this condition causes heart rhythm problems, leading to stroke and heart failure.²

Causes

Rheumatic fever

• Rheumatic fever is a rare autoimmune disease that develops after a bacterial throat infection. If the treatment is improper the immune system may attack its tissues, causing swelling and inflammation in the joints and heart problems known as rheumatic heart disease. The disease symptoms may not appear until years after rheumatic fever.^3,4

Radiation therapy

• People undergoing radiation therapy on the chest area for cancer can develop mitral valve thickening or hardening. The symptoms of the damage to the valve appear 10 to 20 years after the radiation therapy. 

Congenital heart defects

• Babies born with congenital heart defects can have a narrowed mitral valve and suffer from discomfort and symptoms over time. The symptoms may be mild to severe, with severe symptoms being potentially life-threatening and requiring surgery. 

Age

As age advances, there is more chance of calcium deposits around the mitral valve. It narrows the structures around the valve.

Mitral valve prolapse

Mitral valve prolapse is when the valve flops back into the left atrium. It may prevent the valve from closing. Mitral valve prolapse can be mild with no symptoms and may not need any treatment. In severe prolapse cases, it may lead to severe mitral valve regurgitation (the blood leaks back to the atrium from the ventricles), requiring valve repair surgery or replacement.⁵

Causes

Mitral valve prolapse is where the valve leaflets (flaps) have extra tissue or stretch more than usual. It can be due to valve tissue weakness caused by Marfan syndrome or Ehlers-Danlos syndrome.^6,7

Mitral valve regurgitation

Mitral valve regurgitation is the condition that occurs when the valves of the left heart chamber do not close tightly and allow the blood to flow backwards. If the leakage is severe, it may lead to severe mitral valve regurgitation. The patient may need surgery to repair or replace the valve. Without proper treatment, it may cause problems in heart rhythm or heart failure.⁸

Causes

Mitral valve prolapse

• A condition where the mitral valve leaflets flop back and prevent the valve from closing. It causes blood to flow backwards.⁵

Rheumatic fever 

• Rheumatic fever is a rare condition that can develop as a complication after a bacterial throat infection and cause heart problems.³

Congenital heart defect

• Children born with congenital heart defects have problems with the structure of their hearts. In severe cases, they need surgery to repair or replace parts like the mitral valve.

Cardiomyopathy

• Cardiomyopathy is a condition that affects the heart muscles and prevents the heart from pumping blood efficiently to the rest of the body. It can lead to heart failure.

Endocarditis

Infective endocarditis is a condition that is caused by bacteria entering the bloodstream and attacking the lining of the heart chambers and valves. 

Heart attack

• A previous heart attack can damage the heart muscle that supports the mitral valve and may cause severe mitral valve regurgitation. Lack of blood flow to the heart muscles can cause permanent damage or death. 

Aortic aneurysm

The aorta is the main artery in the heart. A bulge in the wall of the aorta is known as an aortic aneurysm, it appears in the weak area of the artery. This may rupture and cause internal bleeding or block the blood flow from the heart to various organs. 

Symptoms of mitral valve disease

The signs and symptoms of mitral valve disease depend on the type of the disease condition and its severity. Some of the common symptoms are: 

• Chest pain
• Blood in the sputum (hemoptysis)
• Dizziness
• Dyspnoea
• Tiredness
• Irregular heartbeat (arrhythmia): The most commonly seen type is atrial fibrillation ^9,10
• Swelling in legs, feet and ankles

Diagnosis

A cardiologist is an expert who examines the patient's heart condition and asks about their medical history. The doctor uses a stethoscope to listen to the heartbeat and look for any indication of a murmur, a sign of mitral valve disease. Some of the tests conducted are: 

• Chest x-ray
• MRI: This helps in assessing the severity of the disease
• Echocardiogram
• Electrocardiogram: This test helps in identifying irregular heartbeats
• Cardiac catheterisation: This is an invasive imaging procedure that helps evaluate the function of the heart by inserting a catheter into the blood vessel through the arm or groin and then into the coronary arteries

Management and treatment

The type of treatment depends on the severity and symptoms of the disease. A diseased or damaged mitral valve needs surgical replacement or repair. Usually, a surgeon performs the surgery but by technological advancements, some hospitals perform minimally invasive robot-assisted heart surgery.

Mitral valve repair

During surgery, the patient is under general anaesthesia while the surgeon patches the valve and reconnects the flaps. They remove any extra tissue present that prevents the flaps from closing and replace the cord that supports it.

Balloon valvuloplasty

In this procedure, the surgeon inserts a balloon catheter into an artery in the arm or groin and moves it up to the mitral valve. The inflated balloon widens the mitral valve.

Transcatheter edge-to-edge repair (TEER)

This method has opted for patients who are not suitable for open heart surgery. The surgeon inserts a catheter with a clip at the end, called a MitraClip, into an artery in the groin and moves it up to the mitral valve. The clip fixes a leaky or torn mitral valve.

Mitral valve replacement

During mitral valve replacement, the surgeon replaces the valve with a mechanical or biological tissue valve made from cow, pig, or human heart tissue. When a biological tissue valve is not working properly, a catheter is inserted for a replacement valve. This method is known as a valve-in-valve procedure. If the mitral valve is replaced with a mechanical valve, the patient is advised to take blood thinners for life to prevent blood clots. A biological tissue valve will eventually break down over time and must be replaced.

Complications

Mitral valve disease can cause many complications depending on the form of the disease and its severity. 

• High blood pressure (hypertension)
• Irregular and fast heartbeat (atrial fibrillation)
• Heart failure
• Blood clots
• Stroke: A life-threatening condition where the brain is not getting enough blood flow, potentially due to bleeding in the brain or a blocked artery

FAQs

How to treat mitral valve disease?

Mitral valve disease is treated according to its severity, the affected valve needs repair or replacement in severe cases.

What lifestyle choices must be made if suffering from mitral valve regurgitation?

• Avoid alcohol and tobacco
• Maintain healthy diet
• Maintain regular exercise

Which is the most common type of mitral valve disease?

Mitral valve prolapse is the most common when the leaflets become loose and the valve does not close properly, allowing the blood to flow backwards.

Can the mitral valve be fixed without surgery?

In the TEER procedure, a MitraClip is inserted through the groin to the heart to clip the torn or leaky valve.

Summary

Mitral valve disease is a group of conditions affecting the mitral valve. It can be acquired (develops over time) or congenital (condition present during birth). The mitral valve lets the oxygen-rich blood from the lungs flow from the left atrium to the left ventricle and other body parts. If the valve does not function, it can lead to mild to severe symptoms. A diseased or damaged mitral valve needs replacement or repair with the help of surgery.