The aortic valve allows blood to flow from the heart’s left ventricle up into the aorta and on to the rest of the body. Aortic stenosis is a narrowing or blockage of the aortic valve. The narrowing occurs when the leaflets change shape or fuse together because of a congenital defect, calcium deposits, or scar tissue. The narrowing decreases blood flow through the valve, forcing the left ventricle to work harder to circulate the right amount of blood. Severe obstruction may lead to the development of an enlarged left ventricle, muscle weakness, heart failure, or arrhythmia.
What Causes Aortic Valve Stenosis?
Aortic valve stenosis is more common in men, and its primary causes are congenital defects, infection, calcium deposits, and scar tissue formation. A normal aortic valve has three leaflets, but approximately two percent of the population is born with only two leaflets. Most of these two-leaflet valves work normally, but in others, they fuse together and do not open or close properly. Rheumatic fever and other infections can scar the leaflets. The aging process can cause calcium deposits or fibrous tissue growth on the leaflets, which distorts them or causes them to fuse together. No matter the cause, the stenosis process makes the leaflets appear as one single, fused leaflet.
Aortic valve stenosis usually produces no symptoms. However, when it becomes severe, physical activity may produce shortness of breath, coughing, dizziness, chest pain, palpitations, and fainting. These symptoms are likely to occur or worsen during exercise or physical exertion.
Aortic valve stenosis can worsen with age, so patients need routine follow-up. Medications may be used to treat the symptoms, but they cannot cure the disease. Severe aortic stenosis is life-threatening, and left ventricular pressure can reach dangerous levels. When this occurs, the valve must be opened. This procedure, called a valvotomy, does not repair the valve; it only relieves the stenosis and left ventricular pressure. It can be performed in either the cardiac catheterization laboratory or in the operating room. Aortic valve leakage is likely to develop after a valvotomy procedure, and if it does, the valve will eventually need to be replaced.
Surgical replacement is used to treat aortic valves that cannot be repaired. The procedure involves removing the defective valve and replacing it with a prosthetic valve. Prosthetic valves can be mechanical (made from materials such as plastic, carbon, or metal) or biological (made from human or animal tissue). Mechanical valves carry the risk of developing a blood clot on the new valve, so patients with mechanical heart valves must take blood-thinning medicine for the rest of their lives to prevent this complication. A stenotic aortic valve can be safely replaced in almost all healthy patients, including those who are 80 years old or more.
If a moderately stenotic aortic valve is discovered in an asymptomatic patient, immediate valve replacement may be recommended due to the possibility that it could quickly progress undetected, causing sudden death. Rarely, a more complex surgery is performed in conjunction with valve replacement to enlarge the aortic root.
Preventative Antibiotics and Heart Valve Disease
Patients with heart valve disease who have an abnormal heart or who’ve had heart surgery risk developing endocarditis. The American Heart Association no longer recommends taking routine antibiotics before certain dental or surgical procedures except for people at the highest risk for bad outcomes if they do develop endocarditis.
Texas Heart Institute www.texasheartinstitute.com/HIC/Topics/Cond/vaortic.cfm
Mayo Clinic www.mayoclinic.org/aortic-valve-disease/
American Heart Association www.americanheart.org/presenter.jhtml?identifier=11068