The aortic valve is the most important valve in the heart valve, it is the gate for the heart to beat out blood to the whole body, so it plays an important function in the human body. Once the aortic valve is narrowed, the heart beats out blood obstructed, one is the heart needs to use more force, and the other is the heart beats out less blood, which will cause the whole body organs to have insufficient blood supply, manifesting as dizziness, blurred vision, weakness, chest pain and other symptoms, serious even cause sudden syncope, sudden death, etc. It is a common cardiovascular disease in the elderly and should be given great attention. Etiology and classification Aortic stenosis can be divided into rheumatic aortic valve lesions, congenital aortic valve abnormalities, and degenerative aortic valve lesions according to the etiology. 1, rheumatic aortic valve lesions. Rheumatic aortic stenosis alone is rare, and is mostly combined with rheumatic lesions of the mitral valve. Currently, rheumatic aortic stenosis has become very rare in western developed countries due to a significant decrease in the incidence of rheumatic fever, and is also on the decline in China, but is still the main cause at this stage. 2, congenital malformation of the aortic valve. Commonly, the aortic valve bilobed malformation, the normal valve is a three-leaf structure, while some in the fetal development process, there are two valve leaves fused into two leaves, the early birth valve function is normal, but with the growth of age, the valve gradually thickened, calcification, valve stenosis occurs. 3, degenerative aortic valve lesions. This type of aortic stenosis occurs mostly in patients over 65 years of age, and in patients with aortic valve lesions over 70 years of age, which is due to aging of the valve structure and is an important manifestation of physical aging, and with the aging of China, the number of degenerative lesion incidence increases year by year. Symptoms and hazards The normal adult orifice area is about 3.0~4.0 cm2, and aortic stenosis can be divided into mild stenosis (orifice area ≥1.5 cm2), moderate stenosis (orifice area 1.0~1.5 cm2) and severe stenosis (orifice area ≤1.0 cm2) according to the degree of stenosis. Some are also graded according to the transvalvular pressure difference across the valve, with the average transvalvular pressure difference being less than 30 mmHg for mild, 30-50 mmHg for moderate, and greater than 50 mmHg for severe. The immediate consequence of aortic stenosis is obstruction of left ventricular blood flow, and in patients with severe congenital aortic stenosis, death often occurs after birth because the left ventricle does not have time to compensate. In adults, aortic stenosis tends to progress gradually, usually over several decades, during which time the left ventricle undergoes compensatory ventricular muscle hypertrophy to accommodate the changes in left ventricular obstruction. The result of increased ventricular wall thickness can produce a decreased volume/volume ratio, reduced chamber compliance, and increased left ventricular end-diastolic pressure. The result is left ventricular diastolic dysfunction, while compensatory hypertrophy can reduce coronary blood flow per unit of myocardium and is also accompanied by a reduction in coronary vasodilatory reserve capacity. When stressful exercise or tachycardia occurs, poor distribution of coronary blood flow can occur and produce ischemia of the endocardium, which exacerbates systolic or diastolic dysfunction of the left ventricle. The typical sign is a systolic increasing-decreasing jet murmur, often accompanied by palpable systolic tremor, heard in the aortic valve auscultation area. As the lesion progresses, a clinical triad of aortic stenosis may develop: exertional dyspnea, angina pectoris, and syncope. Exertional dyspnea is the most common complaint in patients with aortic stenosis, and its occurrence is related to cardiac dysfunction, pulmonary stasis caused by elevated left atrial and pulmonary venous pressure, and also manifests as weakness, dizziness, and other manifestations of inadequate blood supply. 2. Chest pain (angina pectoris) occurs as the only clinical symptom or in combination with other symptoms in 50% to 70% of patients. Moreover, it is more common in patients with combined coronary artery disease, whose manifestation of pain is the same as that of angina, and also has a feeling of pressure behind the sternum, because the mechanism of pain caused by both is the same, but the chest pain of aortic stenosis cannot be relieved by taking nitroglycerin, and even has to be aggravated, so special attention should be paid to the abuse of nitroglycerin when there is no clear cause of chest pain. Patients with aortic stenosis who have frequent chest pain should mainly have the possibility of sudden death, which is the result of malignant ventricular arrhythmias of the heart caused by a sudden lack of blood supply to the heart, and is the most important cause of death in patients with aortic stenosis, and is also the greatest potential risk for patients with symptomatic aortic stenosis. 3, About 30% to 50% of patients with severe aortic stenosis present with mild or transient syncope. Early manifestations are blackness and dizziness, which are the main manifestations of inadequate blood supply to the brain. Patients with severe stenosis may experience syncope, which is another potential risk for patients with aortic stenosis.