What is Aortic Valve Disease?
The aortic valve, a crucial part of the heart, can develop two main types of problems: it can either become stenotic or insufficient. A stenotic aortic valve means that the flaps of the valve, called leaflets, become hard and stiff. As a result, the size of the opening of the valve reduces, increasing the pressure inside it. This situation sometimes slows down the forward flow of blood during systole (a phase of the heartbeat). This can cause various health issues, typically starting with the abnormal thickening of the left part of the heart (left ventricular hypertrophy), and can later cause the heart to enlarge (dilation), reduced heart output, abnormal heart rhythms (arrhythmias), lack of enough blood in the area (ischemia), and so on.
On the other hand, aortic insufficiency happens when the aortic valve does not close properly during diastole (another phase of the heartbeat), causing blood to flow backward from the aorta (the main artery that carries blood from the heart to the rest of the body) into the left ventricle (the chamber of the heart which pumps blood to the body). The result of this backflow of blood is an increase in the volume and wall stress of the left ventricle.
What Causes Aortic Valve Disease?
Aortic stenosis, a condition where the heart’s aortic valve narrows, commonly happens due to two reasons: calcification, which is age-related, and a birth condition known as congenital bicuspid aortic valves. Exceptionally, aortic stenosis can also be a result of rheumatic heart disease, a disease normally seen affecting the mitral valve especially in developing countries. Out of these, calcified aortic stenosis is the most common, believed to be a result of gradual damage to the lining of the heart vessels over many years.
Aortic regurgitation, when the heart’s aortic valve doesn’t close tightly causing some blood to leak back into the left ventricle, can take place in both chronic (long-term) or acute (sudden) forms. Acute aortic regurgitation could be caused by a type A aortic dissection, which involves a tear in the valve, or due to damage from an infection in the heart. Common causes for chronic aortic regurgitation in developing countries align with those of aortic stenosis including calcified disease, congenital bicuspid valve problems, and Marfan syndrome—a genetic disorder that affects the body’s connective tissue.
Other, less usual reasons for chronic aortic regurgitation may include complications from procedures to open up a narrowed heart valve or to replace the aortic valve, and also certain inflammatory disorders such as systemic lupus erythematosus, rheumatoid arthritis, and Takayasu arteritis. In developing countries, the main cause of chronic aortic regurgitation is rheumatic heart disease.
Risk Factors and Frequency for Aortic Valve Disease
Aortic stenosis, a condition that causes narrowing of the heart’s aortic valve, is often seen in older adults, becoming more prevalent from the fifth through eighth decades of life. The occurrence of this condition tends to increase with age. In contrast, the percentage of sufferers with abnormal aortic valve structures decreases as they age. After surgery, two-thirds of patients under 50 were found to have a bicuspid valve, while over 70, 60% had a tricuspid valve.
- Incidence of aortic stenosis per decade of life:
- 0.2% during the fifth decade
- 1.3% during the sixth decade
- 3.9% during the seventh decade
- 9.8% during the eighth decade
- Among post-surgery patients:
- Under 50 years, two-thirds had a bicuspid valve, the rest had a unicuspid valve.
- Between 50 and 70 years, two-thirds also had bicuspid, but one-third had a normal tricuspid valve.
- Over 70 years, 60% had tricuspid valve, and 40% had bicuspid.
On the other hand, aortic regurgitation, a condition where the aortic valve doesn’t close tightly, is estimated to affect about 4.9% of the population. This incidence tends to increase with age until the sixth decade when it starts to decrease. However, as many as 75% of aortic stenosis patients may also have some level of aortic regurgitation but may not report it.
tricuspid valve, and right coronary artery are illustrated.
Signs and Symptoms of Aortic Valve Disease
A thorough examination and detailed patient history are often the first steps towards diagnosing aortic valvulopathy, a disease involving the dysfunction of the main valve that regulates blood flow from the heart. Its symptoms, which might include aortic stenosis (narrowing) or regurgitation (leakage), can be hard to recognize until the condition becomes severe. Hence, a careful heart exam becomes key to catching the problem early on.
In case of aortic stenosis, doctors often observe a notable heart murmur, a specific type of noise produced by turbulent blood flow. This usually occurs during the contraction phase of the heartbeat and can be distinguished best near the sternum, right below the collarbone. You might also experience a various range of symptoms like a noticeable heartbeat, shortness of breath, swelling in your legs, and heart failure in severe cases.
Aortic regurgitation, on the other hand, presents itself uniquely. Acute or severe cases can be detected through an enlarged pulse pressure and a prevalent heart murmur. Chronic cases may exhibit a distinctive, soft, and lengthy diastolic murmur. Patients may also exhibit signs like a pronounced, sudden, and collapsing pulse, involuntary head movement in tune with the heart’s rhythm, finger and mouth pulsations, and more. Severe symptoms can resemble those observed in aortic stenosis and may include chest pain, swollen joints, skin nodules, and other signs of rheumatic heart disease.
The usual symptoms seen in chronic aortic regurgitation or advanced aortic stenosis typically include heart failure and reduced blood flow to the body and heart. This might result in swelling in the legs, difficulty breathing, needing more pillows to sleep comfortably, decreased exercise tolerance, and feeling dizzy or lightheaded. In some severe cases, patients might faint or experience symptoms similar to angina, a condition characterized by chest pain due to reduced blood flow to the heart.
Testing for Aortic Valve Disease
If a doctor suspects a patient might have heart valve disease, based on either the patient’s symptoms or something they noticed during a physical exam, the next step is usually an echocardiogram. This is a kind of test that uses sound waves to create a picture of the heart and to measure how well it’s working. In this case, the echocardiogram would look at three main factors to assess the health of the aortic valve.
These factors are the speed of the blood jetting through the valve, the average amount of pressure on the valve, and the size of the valve’s opening area. These measurements are then used alongside the patient’s symptoms to judge just how serious the valve disease might be.
Sometimes, other tests like a cardiac CT scan or MRI, stress testing, or blood cultures (if an infection is suspected) might be done to find out more about any other existing heart conditions or complications.
Treatment Options for Aortic Valve Disease
Currently, there are no treatments that can postpone the progress of aortic valve disease that does not present symptoms. The approach to management is two-sided: keeping related heart conditions in check, like high blood pressure, heart disease, heart function issues, irregular heartbeat, along with constant monitoring to track disease progression and detect symptoms early. For mild aortic valve disease, heart scans (echocardiograms) should be done every 3 to 5 years, for moderate cases every 1 to 2 years, and for severe but still symptomless cases, every six months to a year. If new symptoms appear, immediate check-up is crucial regardless of the disease stage.
Aortic stenosis, which is where the aortic valve is tighter than usual, may require valve replacement. This procedure can be recommended for patients who don’t show symptoms but exhibit advanced illness according to medical history or stress tests. Or for patients with severe aortic stenosis, but their heart’s main pumping chamber (the left ventricle) isn’t functioning fully. Furthermore, valve replacement may also be on the cards in case of patients who need to undergo another heart surgery.
Patient selection for aortic valve replacement may also consider other factors. For example, symptomless patients who can’t exercise properly due to severe aortic stenosis and low blood pressure, or those with slowed blood flow but reduced left ventricle function. Even instances where patients with moderate aortic valve disease need to undergo other heart surgeries, valve replacement may be considered.
In terms of aortic regurgitation, valve replacement is usually needed for symptomatic patients with severe aortic regurgitation, symptom-free patients with severe chronic aortic regurgitation who exhibit disturbances in their left ventricle function, and patients who need to undergo other kinds of cardiac surgeries.
Patient selection for aortic valve replacement surgery needs to carefully consider expected outcomes. If life expectancy is less than a year post the replacement, or the quality of life is not expected to improve, they wouldn’t be suitable candidates for surgery.
When proceeding with aortic valve replacement, there are two procedures to choose from, surgical or transcatheter methods. The latter method is only suited for aortic stenosis, not for aortic regurgitation. Doctors decide which method is best based on the potential risks involved in surgical valve replacement. If there is a high risk of complications or death, transcatheter aortic valve replacement is preferred. Otherwise, surgical method is usually the way to go. However, some recent studies show that the long-term outcome of both methods is comparable, suggesting transcatheter procedure is safe for any patient, no matter the risk.
Lastly, there’s another procedure used sparingly for aortic stenosis patients, called balloon valvuloplasty. This involves inflating a balloon inside the valve to widen it, but it’s only used as a temporary measure before valve replacement surgery, or to relieve symptoms in patients not suitable for surgery.
What else can Aortic Valve Disease be?
When a patient shows signs of aortic valve disease, doctors have to consider many other conditions that may result in similar symptoms:
- Heart conditions where the heart becomes unusually thick or stiff (Hypertrophic, Restrictive or Constrictive cardiomyopathy)
- Heart failure where the heart does not pump blood as well as it should (Congestive heart failure with reduced ejection fraction)
- Narrowing or blockage of the arteries that provide blood to the heart muscle (Coronary artery disease)
- Irregular heart rhythm conditions (Atrial fibrillation or Atrial flutter)
- Heart disease resulting from a lack of blood supply to the heart (Ischemic heart disease)
- An excess amount of fluid around the heart (Pericardial effusion)
- High blood pressure in the arteries of the lungs (Pulmonary hypertension)
- Long-term lung diseases that block airflow and cause breathing difficulties (Chronic obstructive pulmonary disease or Restrictive lung diseases)
- Low red blood cell count which can cause fatigue and weakness (Symptomatic anemia)
By ruling out these conditions, doctors can accurately diagnose aortic valve disease.
What to expect with Aortic Valve Disease
The outcome of a patient’s condition largely depends on when symptoms begin to show. Patients who don’t develop symptoms tend to live longer. However, for those with severe aortic valve disease who don’t get their valve replaced, the outlook isn’t great; survival rates over three years range from roughly 40 to 60%. On the other hand, those who do have a valve replacement procedure survive at rates between 80 to 90%.
Preventing Aortic Valve Disease
Here are some key points everyone should know:
* Always take your prescribed medications exactly as your doctor has instructed.
* If you’re considering taking any over-the-counter medications, vitamins, or herbal remedies, make sure to check in with your doctor first.
* It’s important to attend all your follow-up appointments, even if you’re not experiencing any symptoms.
* Keeping a healthy weight is important, but before starting any exercise program, it is essential to ask your doctor. This is especially important for patients with aortic stenosis because they need to be careful when exercising.
* If you’re a smoker, giving up smoking is recommended.
