Aortic Stenosis lesion occurs in 25% of all patients with chronic valvular heart disease of rheumatic
origin. The primary abnormality is obstruction to the left ventricle output. There is reduced
cardiac output and a gradually dilating left ventricle and hypertrophy of the heart muscle. Aortic valvular stenosis may follow rheumatic fever but is more commonly caused by progressive valvular calcification (see illustration). This may occur in younger patients with a congenitally bicuspid valve or in elderly individuals with normal three-cusp valves. In the latter group, the aortic valve becomes sclerotic and, with further calcification, stenotic. Approximately 25% of patients over age 65 years and 35% of those over age 70 years have echocardiographic evidence of sclerosis, which appears to be related to atherosclerotic vascular disease and is associated with a higher rate of vascular events. About 10–20% of these will progress to hemodynamically significant aortic stenosis over a period of 10–15 years.
Aortic valve stenosis ( AS ) is a heart condition caused by the incomplete opening of the aortic valve .The upper chambers, the right atrium and left atrium (atria - plural for atrium), are thin walled filling chambers.When the aortic valve becomes stenotic, resistance to systolic ejection occurs and a systolic pressure gradient develops between the left ventricle and the aorta. Stenotic aortic valves have a decreased aperture that leads to a progressive increase in left ventricular systolic pressure. Eventually your heart muscle becomes thicker because it has to pump harder due to the obstruction.The left ventricle pumps oxygen-rich blood into the aorta, which carries it to the brain and the rest of the body. In addition, your heart can pump only a limited amount of blood — and can't provide the increase in blood flow you need for activities such as exercise. Only about 2 percent of the population have biscuspid valves. Most bicuspid valves work normally for a long time — sometimes a lifetime. But some can become thick and narrowed (stenotic) or curled at the edges and leaky (insufficient). A number of conditions cause disease and narrowing of the aortic valve (aortic stenosis). When the degree of narrowing becomes significant enough to impede the flow of blood from the left ventricle to the arteries, heart problems develop. Aortic stenosis occurs 3 times more commonly in men than women.
The aorta is the large artery that originates in the left ventricle (lower chamber) of the heart. Blood flows from the right and left atria across the tricuspid and mitral valves into the lower chambers (right and left ventricles). This leads to pressure overload in the left ventricle, which, over time, causes an increase in ventricular wall thickness (ie, concentric hypertrophy). The right and left ventricles have thick muscular walls for pumping blood across the pulmonic and aortic valves into the circulation. Calcium in the blood can build up on the valve, causing a hardening (calcification) of the valve. Aortic valve stenosis usually results in an abnormal heart sound (heart murmur) that doctors can hear with a stethoscope. When the aortic valve becomes stenotic, the ability of the left ventricle to pump blood out of the heart to the aorta and other arteries is impaired. The thickened heart muscle requires an increasing supply of blood from the coronary arteries, and sometimes, especially during exercise, the blood supply does not meet the needs of the heart muscle, and chest pain, fainting, and sometimes sudden death may occur. If you have severe aortic valve stenosis, you'll usually need surgery to replace the valve. Left unchecked, aortic valve stenosis can lead to serious heart problems.
Causes of Aortic Stenosis
The common Causes of Aortic Stenosis :
- Progressive wear and tear of a bicuspid valve present since birth (congenital).
- Scarring of the aortic valve due to rheumatic fever as a child or young adult.
- Bluish skin colour or fingertips (sometimes seen in babies with congenital heart defects) .
- The main causes of acquired AS include rheumatic heart disease and senile degenerative calcification.
- Aortic regurgitation, in which the aortic valve (between the left ventricle and the aorta) is allowing blood to leak back into the heart.
- Congenital AS caused by a congenital unicuspid or bicuspid aortic valve is usually asymptomatic in the otherwise healthy developing child.
- Aortic stenosis can occur at any age (because the causes are different) but is usually asymptomatic until middle or old age.
- These anatomical/pathological changes are very similar to those observed in senile degenerative calcific stenosis of a tricuspid AV, except that in congenital AS in a bicuspid valve, these changes occur several decades earlier.
Symptoms of Aortic Stenosis
Symptoms of failure may be sudden in onset or may progress gradually. Angina pectoris frequently occurs in aortic stenosis. One-half of patients with calcific aortic stenosis and angina have significant associated coronary artery disease, whereas coronary disease is noted at only half this rate in the absence of angina. Syncope is typically exertional and may be due to arrhythmias (usually ventricular tachycardia but sometimes sinus bradycardia), hypotension, or decreased cerebral perfusion resulting from increased blood flow to exercising muscle without compensatory increase in cardiac output. Sudden death may occur but is rarely the initial manifestation of aortic stenosis in previously asymptomatic patients. Some sign and symptoms related to Aortic Stenosis are as follows :
- Fainting , weakness , or dizziness with activity.
- Breathlessness with activity.
- Sensation of feeling the heart beat ( palpitations ).
- Increased with exercise, relieved with rest.
- Fatigue, especially during times of increased activity
- Crushing, squeezing, pressure, tightness.
- Shortness of breath, especially with exertion.
- Heart palpitations - sensations of a rapid, fluttering heartbeat.
- Lightheadedness or fainting.
Treatment of Aortic Stenosis
Here is the list of the methods for treating Aortic Stenosis :
- If you have aortic valve stenosis, your doctor will recommend that you take antibiotics before certain dental or medical procedures, to prevent the heart infection endocarditis.
- Reduce the amount of work the heart does and improves the flow of blood to the heart muscle.
- This is a procedure in which a balloon is placed into an artery in the groin, advanced to the heart, placed across the valve, and inflated.
- Encourage the body to produce urine that relieves the build-up of fluid in the lungs and lower part of the body
- Surgical valvotomy is an open-heart procedure during which the surgeon opens the valve along the lines of commissural fusion; in many centers this open-heart procedure has been replaced by the less invasive balloon dilation valvuloplasty technique.
- A catheter is inserted into the femoral artery and a balloon is inflated to stretch the damaged valve. Valvuloplasty is effective in reducing symptoms and lasts about 5 - 10 years.
- Actively observing the stability or the progression of aortic valve disease is important so that the right treatment can be started at the right time
- In this type of surgery, surgeons remove the narrowed aortic valve and replace it with a mechanical valve or a tissue valve from a pig, cow or human-cadaver donor.