Complications
Notwithstanding the foregoing, the American Heart Association changed its recommendations regarding antibiotic prophylaxis for endocarditis. Specifically, as of 2007 it is recommended that such prophylaxis should be limited only to those with prosthetic heart valves, those with previous episode(s) of endocarditis, and those with certain types of congenital heart disease.Since the stenosed aortic valve may limit the hearts output, people with aortic stenosis are at risk of syncope and dangerously low blood pressure should they use any of a number of medications for cardiovascular diseases that often coexist with aortic stenosis. Examples include nitroglycerin, nitrates, ACE inhibitors, terazosin (Hytrin), and hydralazine. Note that all of these substances lead to peripheral vasodilation. Under normal circumstances, in the absence of aortic stenosis, the heart is able to increase its output and thereby offset the effect of the dilated blood vessels. In some cases of aortic stenosis, however, due to the obstruction of blood flow out of the heart caused by the stenosed aortic valve, cardiac output cannot be increased. Low blood pressure or syncope may ensue. Causes
Aortic stenosis is most commonly caused by age-related progressive calcification (>50% of cases), with a mean age of 65 to 70 years. Another major cause of aortic stenosis is the calcification of a congenital bicuspid aortic valve or, more rarely, a congenital unicuspid aortic valve. Those with unicuspid aortic valves typically need intervention when very young, often as a newborn.
Using the velocity of the blood through the valve, the pressure gradient across the valve can be calculated by the continuity equation or using the modified Bernoullis equation: Gradient = 4(velocity)² mmHg A normal aortic valve has a gradient of only a few mmHg. A decreased valvular area causes increased pressure gradient, and these parameters are used to classify and grade the aortic stenosis as mild, moderate or severe. The pressure gradient can be abnormally low in the presence of mitral stenosis, heart failure, co-existent aortic regurgitation and also ischaemic heart disease (disease related to the decreased blood supply and oxygen causing ischemia).Echocardiogram may also show left ventricular hypertrophy, thickened and immobile aortic valve, and dilated aortic root. However, it may appear deceptively normal in acute cases. Chest X-ray
A chest X-ray can also assist in the diagnosis and provide clues as to the severity of the disease, showing the degree of calcification of the valve, and in a chronic condition, an enlarged left ventricle and atrium. Computer tomography
The use of CT calcium scoring is gaining spread as a diagnostic tool to complement echo in the assessment of patients with aortic stenosis. Aortic valve calcium scoring by multidetector computed tomography (CT-AVC) is used to quantify the degree of calcification of the aortic valve. According to the 2021 ESC/EACTS Guidelines for the management of valvular heart disease the recommended thresholds indicating severe aortic stenosis are > 1200 AU in women and > 2000 AU in men. Management
Treatment is generally not necessary in people without symptoms.