Aortic stenosis is a commonly seen condition in which the aortic valve has a smaller opening than usual. The left ventricle pumps blood through the aortic valve in order to deliver freshly oxygenated blood to the aorta for distribution throughout the body.
Major causes of aortic stenosis are rheumatic heart disease, being born with a bicuspid aortic valve (which has two leaflets rather than the usual three), and degenerative calcification of the aortic valve.
The underlying process leading to degenerative calcification of the aortic valve is felt to be similar to that underlying coronary artery disease, and the two share common risk factors, such as increasing age, diabetes, tobacco use, high blood pressure, and elevated lipids. In fact, many people with aortic stenosis also have coronary artery disease.
In order to compensate for the obstruction created by aortic stenosis, the left ventricle needs to work harder to pump the blood, which may result in stiffness of the heart (also called diastolic dysfunction) and left ventricular hypertrophy.
An echocardiogram is used to assess the severity of aortic stenosis. A number of different parameters can be measured, including aortic valve area, left ventricular function, extent of left ventricular hypertrophy, measurement of pressure gradients, and the velocity of blood flow across the aortic valve. Pressure gradients reflect the fact that the obstruction requires the pressure in the left ventricle to rise above that of the aorta in order to successfully pump blood through the stenotic aortic valve. More severe aortic stenosis results in a higher velocity of blood flow through the aortic valve.
People with aortic stenosis may remain asymptomatic for many years, and the condition may be discovered by a murmur noted on examination. Aortic stenosis tends to progress slowly, and most can be followed with periodic echocardiograms. However, eventually syncope, angina, or heart failure may develop. If any of these occur the outcome is poor if the aortic valve is not replaced.
The treatment of choice for symptomatic severe aortic stenosis is aortic valve replacement. If the doctors believe that the risk of performing open surgical aortic valve replacement is too high, transcatheter aortic valve implantation (TAVI) can be considered. TAVI is a minimally invasive procedure in which a new aortic valve is placed through a blood vessel inside the diseased aortic valve via a catheter. Since TAVI is a relatively new procedure, the long term outcome is unknown.
Underwriting Aortic Stenosis: Case Studies
Applicant 1 is a 73 year old applicant with mild aortic stenosis who has been well followed, is asymptomatic, and the echocardiogram has been stable for several years. This would be Standard Plus.
Applicant 2 is a 47 year old applicant with a bicuspid aortic valve and moderate aortic stenosis who feels well and has been stable for several years. This would be Table Four.
Applicant 3 is a 53 year old who last saw the doctor four years ago. At that time echocardiography showed severe aortic stenosis. The applicant has not returned for follow up. This is a decline.