Did you know?
Just like every room has a door, the human heart also has its “doors”, four altogether. These “doors” have their own names: aortic valve, pulmonic valve, mitral valve and tricuspid valve.
What’s more interesting is that these four “doors” are all “one-way” doors, which means allowing only one-way through. Just because of this strict restriction, these “doors” allow blood from the heart to flow in one direction, ensuring normal blood circulation in human body and indicating their importance evidently.
Today, let me introduce to you the aortic valve, the most essential door of the heart.
Where is the aortic valve?
Aortic valve is located at the core position of the heart, adjacent to the other three valves. It’s the membrane between the left ventricle and the aorta and controls the flow of the oxygen-rich blood that is pumped out of the heart to the whole body.
Aortic valve has three semilunar leaflets, which are respectively called left coronary leaflet, right coronary leaflet and non-coronary leaflet due to their correlations with the coronary artery ostia. A normal leaflet is thin and translucent, and mainly contains collagen and elastic fibers arranged in certain directions and layers.
According to statistics, aortic valve and the other three valves open and close over 2 billion times in a human life.
Exactly, it’s 2 billion times, ten digits, 2 followed by 9 zeros.
These “doors” of the heart also require maintenance.
No material could stay well after opening and closing 2 billion times, so does the heart’s “doors”. As time goes by, problems will occur.
Due to multiple causes, aortic valve leaflets may become thickened, fibrotic and calcified, and thus become stiff and less active. At the same time, the three leaflets may become adhesive and fused together, which restrict the opening, smooth movement, or full open of the leaflets.
In this way, aortic stenosis is formed, which means the “door” doesn’t open easily and is completely closed.
Why would the “door” of the heart be blocked?
From the perspective of etiology, aortic stenosis can be grouped into three types:
- Rheumatic aortic stenosis
This is the most common type of aortic stenosis in China. Patients with rheumatic aortic stenosis usually have aortic insufficiency and mitral insufficiency at the same time.
- Atherosclerotic aortic stenosis
As people get older, aortic valve also ages gradually, and its leaflets become severely fibrotic and calcified, finally leading to aortic stenosis, also called degenerative aortic stenosis. It’s an important manifestation of the aging body, more common in people above 65 years old. With the aging population, the number of such patients in China is increasing too.
- Congenital aortic stenosis
A normal aortic valve has three leaflets. Congenital aortic stenosis occurs due to leaflet fusion during fetal development, resulting in bicuspid aortic valve. In early years, there are no obvious symptoms. But as such patients get older, the leaflets would gradually become thickened and calcified.
What would happen after the “door” fails to function properly
Aortic valve is the most important “door” for the heart to supply blood to the whole body. Once it gets narrowed, the blood pumped out of the heart would be blocked. It might be asymptomatic in many patients for a long period of time and usually diagnosed firstly by echocardiogram.
Aortic stenosis shows no obvious clinical symptoms until the aortic valve becomes severely narrowed, and could easily get worse by cold, fever, fatigue, emotional excitement or weather changes. So, to what symptoms should we be alert for possible aortic stenosis?
Atrial fibrillation exists in 10% of the patients with aortic stenosis, and causes elevated pressure in the left atrium and significantly reduced cardiac output. Clinically, the conditions may deteriorate rapidly, leading to severe hypotension, syncope or pulmonary edema. Aortic valve calcification affects the conduction system, causing atrioventricular block. Left Ventricular Hypertrophy (LVH), endocardial ischemia or coronary embolism may cause cardiac arrhythmia. Both the foregoing circumstances may lead to syncope and even death.
- Sudden cardiac death
Sudden cardiac death occurs usually in patients with previous symptoms, and rarely in asymptomatic patients, only in 1%-3% of asymptomatic patients.
- Subacute infective endocarditis
Subacute infective endocarditis is not a common symptom. Young patients with moderate valve malformation are at high risk of infective endocarditis compared with elderly patients with calcified valve stenosis.
- Systemic embolism
Systemic embolism is a rare symptom. Embolus may come from calcium from calcified cardiac valves or microthrombus of the thickened bicuspid aortic valve. Cerebral embolism is most common, and also occurs to the retinas, limbs, intestines, kidneys, spleen and other visceral organs.
- Heart failure
After the occurrence of left-side heart failure, the nature duration is significantly shortened, so end-stage right-side heart failure is uncommon. About 50%-70% of such patients were died of congestive heart failure.
- Gastrointestinal bleeding
The incidence of gastrointestinal arteriovenous malformation is increased in some patients with severe aortic stenosis. So, patients with severe aortic stenosis are prone to gastrointestinal bleeding.
Other symptoms: patients with long-term aortic stenosis may show systemic symptoms, such as hyperhidrosis, palpitations, fatigue, weakness, etc. due to autonomic nerve function disorder and enhanced sympathetic nerve tension. These symptoms may get worse as the condition progresses and seriously affect the quality of life.
The heart seems strong as it supplies blood to the whole body, but it’s actually rather weak. We would like to remind everyone to take good care of the heart and pay attention to rest every day.