About heart valves

Your heart is the most important muscular organ in your body.

It is a two-sided pump that beats about 100,000 times a day (more than 2 billion times in an average lifetime) to keep your blood circulation going.

The right side of the heart pumps blood through the lungs where it picks up oxygen. The left side of the heart receives the blood containing oxygen and pumps the blood to the rest of your body.

Your heart is made of four compartments, called chambers: the two receiving upper chambers known as atria and the two pumping chambers known as ventricles.

Their function is to store the blood and then push it outside.

Four valves control the blood flow to and from the heart chambers. They open and close in a pulsatile way, filling and emptying the atria and the ventricles.  

• The aortic and pulmonary valves control blood flow out of the ventricles to other parts of the body.
• The mitral and the tricuspid valves control blood flow from the atria to the ventricles.

Heart valves ensure that blood always flows freely in only one direction and that there is no reverse flow.  When the valves fail to move blood properly, the heart cannot efficiently pump blood, which may lead to adverse consequences. 

Heart valve disease occurs when the heart valves do not work properly.

It can occur in any single valve or a combination of the four valves, but diseases of the aortic and mitral valves are the most common, affecting more than 100 million people worldwide, thereby constituting, an important public health problem.

The pulmonary and tricuspid valves are less affected by diseases as they are under less stress because the right pumping chamber does not need to generate as much force to push blood to the lungs.

Two types of problems can disrupt blood flow though the valves:

Valvular Stenosis (or narrowing)

Happens when a valve does not open wide enough and only a small amount of blood can flow through the valve. Because of a narrowed valve, your heart must work harder to pump the same quantity of blood through your body.

Valvular Regurgitation (or insufficiency)

Happens when a valve does not close properly and blood leaks backward instead of moving in the proper one-way flow. Because of an insufficient valve, less blood can flow to the rest of your body and your heart must work harder to pump the same quantity of blood through your body.

Valve disease can develop before birth (congenital) or can be acquired sometime during one’s lifetime (related to age or brought on by another condition).

The cause of valve disease is most likely linked to one of the following:

Congenital defects 

The most common congenital heart defect is a valve where only two leaflets grow instead of the normal three (called a “bicuspid valve”). Over the years, this defect generally leads to aortic valve stenosis.

Age-related valve disease

The most common and serious age-related valve diseases are:

• Aortic valve stenosis resulting from calcification: calcium amasses in the heart over the course of a lifetime, damages the valve and restricts the amount of blood flowing through the valve.
• Mitral valve regurgitation resulting from myxomatous degenerative valve disease.

Related illnesses and other conditions

Rheumatic heart disease is the world’s most common acquired cardiovascular disease, mostly affecting emerging economies. It is caused by rheumatic fever, an illness that sometimes occurs after untreated strep throat or scarlet fever. This illness is most common in children ages 5–15 but can develop in adults.

It may provoke valve stenosis and/or regurgitation with a predilection for the mitral valve, at the entrance of the heart, which is more exposed to clotting complications.

Infective endocarditis or injury (coronary artery disease, heart attack, etc.) could also cause valve disease.

When valves become damaged, the heart fails to move blood properly. If the valve disease is mild, there may be no symptoms. If it is more serious, symptoms may develop such as weakness, fatigue, palpitations, chest pain, or shortness of breath.

If not treated, advanced heart valve disease can cause heart failure, stroke, blood clots, or death due to sudden cardiac arrest.

Treatments for heart valve disease depend on various factors like the valve affected (aortic, mitral, tricuspid, or pulmonary), the type and severity of the disease, the age of the patient, his/her medical condition, his/her lifestyle, and medications that he/she might be taking.

Medication

In some cases, medicines may help ease the pain of symptoms for a period of time. However, medicines cannot reverse heart valve damage, which may also continue to progress even with medications.

Valve repair

In some cases, a surgeon may repair heart valves through different techniques. Repair procedures are common with mitral valve and tricuspid valves regurgitation but are often impossible with aortic or pulmonary valves disease.

Repairs of age-related mitral valve leaks are performed today with good mid term results. 

Repairs of aortic valve deficiency in the young were recently explored. In many cases valve repairs appeared to be not feasible because of calcium deposits and local inflammatory scars.

Long-term outcomes of these surgical techniques remain uncertain. They may allow postponing valve replacement only for a while. Overall, they are difficult to standardize and their longevity remains challenging since heart valves must support high closing loads about 100,000 times a day for many years. 

Valve replacement

When the valve disease is severe and/or concerns the aortic valve, valve replacement may be required. Without an aortic valve replacement, several studies suggest that 50% of patients with severe aortic stenosis will not survive more than an average of 2 years after the onset of symptoms.

The diseased valve is generally removed and replaced with a mechanical or tissue artificial heart valve. The replacement can be performed using traditional heart valve surgery or minimally invasive approaches:

• Traditional heart valve surgery:  a 15–20 cm incision is made to divide the breastbone and to provide direct access to the heart with a good visualization. This is a common procedure, still considered as the gold standard. It has been performed for more than 50 years, showing excellent recovery statistics.
• Minimally invasive heart valve surgery: a 5–10 cm incision is made without opening the whole chest. This surgery reduces blood loss, trauma, length of hospital stay and may accelerate recovery. Minimally invasive heart valve surgeries have been performed for more than 15 years and have recently been improved thanks to video-assistance. Several reports have been published detailing these techniques and confirming that they could be performed safely and effectively in both aortic and mitral positions. They have gained in popularity and results suggest that many patients may be candidate for this minimally invasive surgery.
• Minimally invasive catheter-based procedure (TAVI or TAVR):  This procedure has been offered by cardiologists to patients deemed inoperable, typically those over 75 years old suffering from severe Aortic Stenosis, and generally with multiple severe concomitant diseases.