Valvular stenosis is a condition in which there is a narrowing, stiffening, thickening, fusion or blockage of one or more valves of the heart. As a result, the defective valve can interfere with the smooth passage of blood. Valvular stenosis may occur in any of the four valves of the heart: the aortic valve, the mitral valve, the tricuspid valve or the pulmonic valve.

Valvular stenosis may be a congenital defect, meaning it is present at birth. It also may be acquired after birth from certain medical conditions, such as rheumatic fever.

Mild valvular stenosis may not show any symptoms, but as the stenosis worsens, symptoms of heart failure may develop (e.g., shortness of breath or dizziness). Therefore, regular physical checkups are very important. It is also important to report any unusual symptoms (e.g., fainting) because these may be signs of more severe valvular stenosis.

Valvular stenosis may be first suspected from a heart murmur detected by a physician through a stethoscope. Tests that may be used to diagnose the type and severity of valvular stenosis include electrocardiogram (EKG), chest x-ray and echocardiogram.

According to the American Heart Association's 2006 Heart and Stroke Statistical Update, valvular heart disease is responsible for more than 19,900 deaths each year in the United States and is a contributing factor in about 42,600 deaths. The majority of these cases involve disorders of the aortic valve (62 percent) and the mitral valve (14 percent). Deaths due to pulmonic and tricuspid valve disorders are more rare (.05 and .08 percent, respectively).

People who have valvular stenosis may need to take antibiotics before undergoing any type of medical, surgical or dental procedure. Other treatments for valvular stenosis may include medications such as anticoagulants and surgeries to perform heart valve repair or replacement.

Valvular stenosis is a condition in which there is a narrowing, stiffening, thickening, fusion or blockage of one or more valves of the heart. The four valves of the heart are the aortic valve and mitral valve on the left side of the heart, and the pulmonic valve and tricuspid valve on the right side of the heart.

The narrowed (stenosed) valve(s) may interfere with blood flow through the heart or from the heart into the arteries that lead to the body (aorta) and lungs (pulmonary artery). Normally, blood flows smoothly through the valves when they open. When a narrowed valve prevents blood from flowing freely, the heart must work harder. Over time, this overload can damage the heart’s lower chambers (ventricles) and upper chambers (atria). This may be accompanied by other conditions, such as:

In a normally functioning heart, each of the four valves has its own set of “gates” or flaps that swing open to let blood flow from one area to the next. After swinging open, the flaps should neatly close until the next cycle begins. Thus, blood should flow smoothly only in one direction and only when the valves are open. Any restriction or narrowing (stenosis) of the valve opening limits blood flow.

The routes traveled by oxygen-rich and oxygen-poor blood are as follows:

Potential causes of valvular stenosis

Valvular stenosis may develop before birth (e.g., is inherited or congenital) or may be acquired after birth as a result of other conditions, such as:

Types of valvular stenosis

There are four types of valvular stenosis, which correspond to the four types of heart valves: aortic stenosis, mitral stenosis, tricuspid stenosis and pulmonary stenosis.

Aortic stenosis is the narrowing of the aortic valve, located between the left ventricle and the aorta. Aortic stenosis is the most common type of valvular stenosis, as well as the most common type of valvular heart disease in general. It is estimated to occur in four of every 1000 live births. The severity of aortic stenosis can vary and is usually not detected in children until they are school-aged.

When the valves are thickened but flow is not blocked, the condition is known as aortic sclerosis, which is a common condition in patients who are over 65 years old (25 percent of this population has some form of the condition). Though this was previously believed to be a harmless condition, recent findings indicate that patients with aortic sclerosis are at a 50 percent higher risk for cardiovascular disease and heart attack. They are also more likely to develop aortic stenosis.

Less common variations of AS include:

• Subaortic stenosis. A condition in which AS occurs because of an obstruction in the left ventricle below the aortic valve.
  
  
• Supravalvular AS. A condition in which the blockage is located above the valve. This is sometimes known as the “hourglass deformity” because of the constricted shape of the aorta and the aorta valve.

In all forms of aortic stenosis, the left ventricle is forced to work harder because the flow of blood from the left ventricle to the aorta is compromised. Eventually, the walls of the ventricle can enlarge and thicken (a condition known as left ventricular hypertrophy), wear out and lead to heart failure. Proper diagnosis and appropriate treatment are crucial in repairing the underlying problem and preventing this destructive cycle from getting started.

Aortic stenosis can be caused by any of the following:

• Congenital heart disease. In this situation, the child is born with a bicuspid (two-flapped) or unicuspid (one-flapped) aortic valve rather than a tricuspid (three-flapped) aortic valve. While this opening often does not initially block blood flow, the aortic valve does not open as widely as it should, leading to rough and turbulent blood flow. The resulting “wear and tear” on this malformed valve can lead to aortic stenosis.
  
  
• Buildup of calcium. A progressive disease called idiopathic calcific aortic stenosis or senile calcific aortic stenosis  may occur, mostly in elderly people. In this disease, the valve cusps become thick and stiff from a buildup of calcium. The valve’s mobility is decreased as the buildup weighs down and fuses the aortic valve’s flaps, and the heart is overworked as it tries to pump an adequate blood flow to the rest of the body.

Mitral stenosis is a narrowing of the mitral valve between the left atrium and left ventricle. The valve can become so narrowed that it is little more than a slit. This leads to a reduction in the blood flow to the left ventricle, decreasing overall cardiac output. Also, in pure mitral stenosis, the right side of the heart is overburdened as blood backs up through the lungs and pulmonary blood vessels. This places additional pressure on the right ventricle and atrium and may result in right-sided heart failure. In some cases, however, mitral stenosis occurs in conjunction with some form of aortic stenosis, which may result in left-sided heart failure.


Mitral stenosis can be caused by one of the following:

• The most common occurrence is in women (80 percent of cases) who have experienced rheumatic fever. This may result in fusion of the valve leaflets, thickening or calcification of the valve leaflets, or thickening and shortening of the small strands that connect the valve leaflets to the heart wall (chordae tendineae). Rheumatic fever is rare in the United States, although it is still prevalent in developing countries.
  
  
• Rarely, it may be caused by a heart defect or other form of congenital heart disease.

Symptoms of mitral stenosis typically appear when the patient is in his or her 40s or 50s. Symptoms tend to be aggravated by exercise of periods of excitement, when the body's heart rate naturally increases. Sometimes symptoms appear earlier, such as during pregnancy, when the body's increased blood demands increase the heart's workload.

Tricuspid stenosis is a narrowing of the tricuspid valve, located between the right atrium and the right ventricle. Even when rheumatic fever was relatively common, the occurrence of tricuspid stenosis was relatively rare.

The congenital form (developing before birth) of pulmonic stenosis involves the partial fusion of two or three leaflets of the opening of the pulmonic valve. Its occurrence today is rare.

Pregnant women with valvular disease require extra medical attention before, during and after the pregnancy. This is largely due to the otherwise normal increase in cardiac output during pregnancy. Some heart valve conditions, like mitral valve prolapse, are not typically associated with pregnancy complications. Severe aortic stenosis, though, should be corrected before a woman becomes pregnant. Depending on the type of valve disorder, women will be advised to have regular visits to a cardiologist during the course of their pregnancy.

Like other types of valvular heart disease, valvular stenosis may go unnoticed for years because mild forms tend to produce no symptoms. More severe forms may cause symptoms such as:

• Stroke, usually due to a blood clot that forms in the left atrium due to mitral stenosis

Though these symptoms are the problems that patients may bring to their physician’s attention, valvular stenosis may also produce a number of signs that only the physician will be able to find. These signs include:

• Heart murmur, as detected by a physician through a stethoscope
  
  
• Lung congestion
  
  
• Arrhythmias (abnormal heart rhythms), including atrial fibrillation
  
  
• Hypotension (low blood pressure)
  
  
• Blood clots
  
  
• Changes in blood pressure between the aorta and the left ventricle for aortic stenosis

The diagnosis of valvular stenosis will begin with the physician obtaining the patient’s medical history and performing a physical examination. As part of the physical examination, the physician will listen to the patient’s heart through a stethoscope. Telltale murmurs can indicate the location and nature of some valve diseases, such as aortic stenosis – a condition in which the sound of the blood flow through the damaged valve is turbulent and distinctive. The sounds of mitral stenosis, tricuspid stenosis and pulmonic stenosis have their own distinctive characteristics.

As part of the physical examination, the physician will also listen for lung congestion and assess for the presence of edema. An abnormal pulse will confirm the presence of an abnormal heart rhythm (arrhythmia).

The next diagnostic step typically will be an electrocardiogram (EKG). This is a recording of the heart’s electrical activity as a graph on a moving strip of paper or video monitor. The highly sensitive electrocardiograph machine helps detect heart irregularities, disease and damage by measuring the heart’s rhythms and electrical impulses. This test can indicate if any of the heart’s chambers are enlarged (the left ventricle in particular) and if arrhythmias are occurring.

If the patient’s history, physical examination and EKG suggest the presence of valvular stenosis, then additional tests will be ordered. Noninvasive tests include:

• Chest x-ray. A radiation-based imaging test that offers the physician a picture of the general size, shape, and structure of the heart and lungs. An enlarged heart can indicate damage or dysfunction, while congestion of the lungs may indicate heart failure.
  
  
• Exercise stress test. An EKG is performed while the patient exercises in a controlled manner on a treadmill or stationary bicycle at varied speeds and elevations. The reaction of the heart under exertion can be measured and evaluated, and the functional significance of the valvular stenosis can be assessed.

If these noninvasive tests do not offer enough information, an invasive procedure called a cardiac catheterization may be done. During the cardiac catheterization, pressures will be measured to determine the severity of the stenosis. To measure pressures in different chambers and structures of the heart, catheters may be guided into different areas of the heart. For instance, with aortic stenosis, catheters may be used to measure and compare blood pressure in the left ventricle versus the aorta. Because of the narrowed aortic valve, the blood pressure is higher in the left ventricle.

Newer approaches being developed include special CT scans in which multiple images (multi-slices) can obtain actual images of the heart valves and are able to measure actual opening dimensions of the stenosis.

A coronary angiogram may also be done to ensure that the coronary anatomy is normal. To perform this test, the physician injects a special dye (contrast medium) that is visible to x-ray into the coronary arteries through a catheter inserted into the coronary arteries. Then the coronary angiogram can be taken. Following the coronary angiogram, a left ventricular angiogram will be performed.

If significant narrowing of the coronary arteries is found, physicians may correct this situation by placing bypass grafts at the same time as surgery for the stenotic valve.

The specific course of treatment depends upon the nature and severity of the valve disease. Some conditions, when mild, may require little treatment besides taking antibiotics before any dental or medical procedures to protect against infection of the heart lining. Other valve abnormalities may require medication and/or surgery. Regardless of the nature and severity of the valve defect, early detection and diagnosis can decrease the potential for significant and sometimes irreversible damage.

Drugs will not cure the underlying disease, but they can minimize symptoms by easing the heart’s workload and regulating the heart rhythm. Medications that may be prescribed include:

In aortic stenosis, researchers have found that statins, a type of cholesterol-reducing drug, are effective in reducing calcium deposits in and around the heart. Early studies show that, while lower cholesterol levels did not have an impact on aortic stenosis, statin therapy slowed its progression. This could be due to its effect on calcium and reducing C-reactive protein and overall inflammation, which has been linked to aortic stenosis.

In more severe cases, medications may not be enough to control long-term symptoms. The main treatment option for correcting heart valve abnormalities is through a surgical interventional procedure, including:

• Heart valve repair or replacement. Using a prosthetic valve – mechanical or tissue (from a pig or cow), defective valves are replaced with healthy ones. This is an open-heart surgery that requires the use of a heart-lung machine. Patients who have received a mechanical valve are at an increased risk of blood clot formation and must take anticoagulants for the rest of their lives. Valves that come from animal donors do not require anticoagulation but wear out more quickly and may require replacement. Therefore, mechanical heart valves are often recommended for younger patients who can withstand anticoagulation and hope to avoid another valve replacement surgery in 10 or 15 years.
  
  Surgeons are also exploring heart valve replacement without the need for open-heart surgery. The new, less invasive procedure, known as percutaneous transcatheter heart valve implantation, involves the use of balloon catheters and large stents introduced through a puncture in the skin in the groin area. The new heart valve is transported via the stent to the site, where the stent is then expanded to implant the valve. For patients who are not able to undergo open-heart surgery, due to age or physical condition, percutaneous heart valve implantation may significantly affect survival and quality of life.
  
  
• Certain minimally invasive heart valve surgeries. This includes robotic visualization surgery. Ongoing studies find that robotic surgery can be performed for some types of valve repairs. Robotic surgery involves voice-activated robotic “hands” at the operating table, with the cardiac surgeon manipulating the hand controls. The surgeon views the procedure through an endoscope, a slim optical tube with an attached camera positioned inside the chest. Advantages of this and similar procedures are small incisions, less surgical trauma and a shorter operative and recovery period.
  
  
• Commissurotomy. The surgeon widens a narrowed valve by cutting or shaving the hard, thick points where the valve leaflets meet.
  
  
• Other surgical replacement of valve(s). Surgeries include the Ross Procedure in which the patient’s pulmonic valve is moved to the aortic position with the pulmonic valve being replaced with a pig valve.
  
  
• Balloon valvuloplasty. A procedure in which a balloon-tipped catheter is used to widen and separate stenotic valve flaps.
  
  

For individuals with asymptomatic aortic stenosis, treatment may only involve monitoring to make sure that the heart's structure and function are not significantly weakened.

In the area of stem cell research, researchers are finding that cells from a patient’s own blood vessels can be “grown” over biological valves taken from pigs or human cadavers. Scientists remove the cells from the biological valve, leaving only elastic tissue that retains the valve’s shape. The patient’s cultured cells are then grown over the elastic tissue. After about one year, the new valve is implanted into the patient. It has been shown that this procedure resulted in fewer post-operative complications (e.g., fever, hospital stay) compared to conventional valve replacement.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients or parents may wish to ask their doctor the following questions related to valvular stenosis:

1. What type of valvular stenosis is present?
   
   
2. What tests will be used to diagnose the condition?
   
   
3. How severe is the condition?
   
   
4. Is the stenosis a congenital abnormality?
   
   
5. What problems can be caused by the stenosis?
   
   
6. Will I be prescribed medications? If so, what type and for how long?
   
   
7. Is surgery necessary for the stenosis? If so, what type?
   
   
8. How quickly does the surgery need to be performed?
   
   
9. If I'm getting a replacement valve, what type will be used?
   
   
10. Will I need to be on anticoagulation therapy after surgery?
    
    
11. How long will a replacement valve last?
    
    
12. What restrictions do I have with this condition?
    
    
13. How will my condition be monitored?
    
    
14. Are there other treatment options available to me?
    
    
15. Are my children at higher risk for this condition I have it?