Diagnosis of Aortic Stenosis
The symptoms of shortness of breath, passing out, and chest pain (angina), suggest a diagnosis of aortic stenosis. However, these symptoms may be caused by many other conditions and it is necessary for a physician to confirm the diagnosis by a physical examination, an echocardiogram, and/or cardiac catheterization.
Some patients may not develop symptoms, and aortic stenosis may be suggested by the incidental discovery of a heart murmur, which the physician hears through a stethoscope when listening over the chest. A heart murmur is a characteristic rumbling sound produced by turbulent blood flow through a stenotic aortic valve. The physician also checks the pulse of the carotid arteries in the neck, which is characteristically diminished in intensity, and listens to the lungs for audible signs of fluid accumulation, which are additional indicators of aortic stenosis.
When aortic stenosis is suspected, an echocardiogram (cardiac echo) is usually performed. Echocardiogram uses a microphone-like device to transmit and receive sound waves that travel through the chest wall to the heart, and then are reflected back. The reflected sound waves are translated into images of the heart, including the aortic valve, chambers, and walls.
Echocardiogram also is used to calculate the degree of stenosis by measuring the pressure change between the left ventricle and the aorta, and to assess thickening of the walls, the pumping function, and the amount of dilation (increased diameter) of the left ventricle.
A normal aortic valve opening is at least 2 cm. In mild aortic stenosis, the valve opens 1.01.3 square cm; in moderate aortic stenosis, the open valve area ranges from 0.80.9 square cm; and in severe aortic stenosis, the open aortic valve area is calculated to be less than 0.8 square cm.
If the degree of aortic stenosis remains unclear after physical examination and echocardiogram, cardiac catheterization is performed. In this procedure, a catheter is passed through an artery in the leg (femoral artery) up the aorta, across the aortic valve, and into the left ventricle. This catheter is used to measure the pressure in the left ventricle and in the aorta, and to calculate the pressure gradient across the stenotic aortic valve. The degree of stenosis is calculated by measuring the flow of blood in the body.