Bicuspid Aortic Valve – Valvular Heart Disease

00:00 Let’s talk for a few minutes about the bicuspid aortic valve. Approximately 1% of all live births in the United States are patients with a bicuspid aortic valve. This valve wears out faster than a tricuspid or three cusp aortic valve and here we see a very good example of an autopsy specimen. You can see there's just two leaflets with a central slit like opening. So, this is a patient who already had a fair amount of aortic stenosis from their bicuspid aortic valve when they died.

00:33 Why does the bicuspid aortic valve develop scarring and stenosis? Well, first of all, you can…let’s think about it as if we were a structural engineer. You're putting the same stress over two cusps that normally are over three cusps. No surprise that the cusps wear out, get scarred and injured faster than if you had a three cusp valve.

00:56 Secondly, it turns out that there is turbulent flow above the bicuspid aortic valve and this has two implications by the way. One, it often causes some platelet plugging that deposit onto the valve and thereby set of an… an inflammatory reaction that can lead to atherosclerosis and scarring. But, in addition, this abnormal flow characteristic is often associated with enlargement or even aneurysm formation of the ascending aorta and these patients are not only at increased risk of developing aortic stenosis or occasionally aortic regurgitation, but also dissection of the aorta which can be a life threatening condition. So, bicuspid aortic valve patients require careful follow up, usually with echo and also to elicit any symptoms that they might be having. So, in conclusion, the bicuspid aortic valve is inherited in approximately 1% of the population. It is often inherited with other congenital heart disease lesions. For example, a ventricular septal defect or coarctation of the aorta and once those have been repaired, the bicuspid valve remains and can eventually develop into aortic stenosis. In addition, the bicuspid aortic valve can have aortic complications such as an aortic aneurysm or dissection of the aorta. The valve is usually identified by two dimensional echocardiography. There are a number of complications that can occur as I’ve already mentioned such as dissection of the aorta, but the most important one is endocarditis of the valve. It’s at an increased risk for endocarditis and of course, eventually, aortic stenosis. When a tricuspid valve becomes stenotic, it‘s usually because of atherosclerosis, but in the bicuspid aortic valve, when it becomes stenotic, it’s because of wear and tear put onto the two cusps of the valve as opposed to spread over the three cusps. There’s some atherosclerosis in the bicuspid valve when it gets stenotic. But, usually, these valves become a problem in the 50s or 60s as opposed to the atherosclerotic tricuspid aortic valve disease which becomes a problem after age 70 or even after age 80.