Aortic valve stenosis

Introduction to aortic valve stenosis Aortic valve stenosis, the most common in congenital aortic stenosis, accounting for 60%. The main lesion is aortic valve malformation, the valve is narrow, generally not associated with aortic annulus dysplasia. The malformed aortic valve can be fused into a single leaflet, or a double leaflet, a three-valve leaflet, or even four leaflets, of which the double leaflet deformity is the most common, accounting for 70%. The aortic valve presents thickened left, right or anterior and posterior lobes, and the two junctions of the leaflets fuse with each other. The small proximal part of the junction is the aortic valve. In some cases, the left valve leaflets are larger, and there is a thick strip of shallow ridges, which is a trace of the fusion between the left coronary valve and the non-crown valve. 2% of the aortic valve in the crowd showed double leaflet malformation. If the junction of the two leaflets does not fuse with each other, aortic valve stenosis does not occur. However, after the age of 30, due to blood vessel turbulence caused by valve trauma, the valve leaf thickened, fibrosis or even calcification, the valve mouth gradually narrowed or closed. Or clinical symptoms appear when complicated by bacterial endocarditis. In 30% of cases, the aortic valve consists of three thickened leaflets, each of which is similar in size, with the marginal portions of the three leaflet junctions fused together, and the central portion is vaulted to the ascending aorta, dome The center is a narrow mouth. In a small number of patients, the aortic valve is a single-leaf type, and the aortic valve is shaped like an inverted funnel. The valve is narrow and long, located in the central portion of the valve or on one side. Sometimes a shallow ridge trace of a leaflet junction fusion can be seen. This type of aortic valve stenosis can present severe symptoms of stenosis in infants and young children. The four-leaf aortic valve is rare, and the four leaflets may be similar in size, or one leaflet is much smaller than the other three leaflets. The four-leaf aortic valve generally functions normally and does not cause symptoms of stenosis. It is only found during autopsy. basic knowledge The proportion of illness: the incidence rate is about 0.004%-0.006% Susceptible population: more common in patients with rheumatic fever Mode of infection: non-infectious Complications: aortic regurgitation

Causes of aortic valve stenosis

The disease is a congenital disease and the cause is not clear.

pathology:

Aortic valve stenosis: the most common in congenital aortic stenosis, accounting for about 60%, the developmental malformation of the aortic valve can be fused into a single leaflet, or double-lobed, three-lobed, or even four leaflets Among them, double leaflet malformation is the most common, accounting for about 70%. The aortic valve presents thickened left, right or anterior and posterior leaflets. The two borders of the leaflets merge with each other, and the central part of the junction is small. The fracture is the aortic valve orifice. In some cases, the left valve leaflet is larger and has a thick strip of shallow ridge, which is the trace of the fusion between the left coronary artery and the non-crown valve. Roberts estimates that about 2% of the population is in the crowd. The valve is a double-valve deformity. If the junction of the two leaflets does not fuse with each other, the aortic valve stenosis does not occur. However, after 30 years of age, the valve wound is caused by blood turbulence, the leaflets are thickened, fibrosis or even calcification. Clinical symptoms appear when gradual stenosis or insufficiency, or due to bacterial endocarditis. About 30% of cases aortic valve consists of three thickened leaflets, each with similar size, three leaflets The edge of the junction merges with each other, the center The ascending aorta bulge is vaulted, and the center of the dome is a narrow valve. A few patients have a single-leaf aortic valve. The aortic valve is shaped like an inverted funnel. The valve is narrow and long and is located in the central part of the valve. Or on one side, sometimes a shallow ridge trace of a leaflet junction is visible. This type of aortic valve stenosis can present severe symptoms of stenosis in infants and young children. The four-leaf aortic valve is rare. The four leaflets may be similar in size, or one leaflet is much smaller than the other three leaflets. The four-leaf aortic valve generally functions normally and does not cause the symptoms of valve stenosis. It is only found in autopsy.

Prevention of aortic valve stenosis

1, patients with aortic valve stenosis should be eaten: diet is light and nutritious, the first choice is milk. Followed by fish, the nutritional value of fish is high and easy to absorb, and the nutrition of soybean products is better. Pay attention to the balance of the diet, three meals a day should be regular, do not overeating.

2, patients with aortic valve stenosis should avoid eating: avoid spicy irritants, do not drink alcohol, do not have damage to the affected area.

Aortic valve stenosis complications Complications aortic regurgitation

Can be complicated by bacterial endocarditis, aortic valve insufficiency and so on.

1, bacterial endocarditis

Bacterial endocarditis may occur in a variety of heart defects, but the most common are aortic valve damage, open arterial catheter (unrepaired), tetralogy of Fallot, ventricular defect, aortic stenosis and Mitral valve prolapse and mitral regurgitation, endocarditis rarely occurs in the atrial sacral defect (type 2) or pulmonary stenosis, may occur in the congenital heart defect after surgical repair, in addition to ventricular fistula Complete repair of the defect and open arterial catheter (6 months after surgery).

Most of the aortic valve stenosis caused by acute bacterial endocarditis, usually with sudden high fever (39 ~ 40 ° C), heart rate, fatigue, rapid and serious valvular damage as the first symptom, the endocardium under the detachment Sputum organisms (emboli) flow with the blood to other parts of the body, resulting in infection of these parts, pus accumulation at the base of the infected valve and the embolic embolism, and the heart valve perforation occurs in a short time (several days). The blood is flowing back, some people have shock, the kidneys and other important organs have severe dysfunction (this state is called sepsis syndrome), and the intra-arterial infection causes the arterial wall to weaken, which can cause arterial rupture and life-threatening (especially Other symptoms of acute bacterial endocarditis include: chills, joint pain, pale skin, rapid heartbeat, subcutaneous pain nodules, confusion, and hematuria.

2, aortic valve insufficiency

Under normal circumstances, patients with aortic regurgitation are asymptomatic for a long time, even if the obvious symptoms of aortic regurgitation can be as long as 10 to 15 years; once heart failure occurs, it progresses rapidly, mainly Some of the following symptoms:

(1) palpitations: the discomfort of heart beat may be the earliest complaint, due to the obvious increase of left ventricle, increased apex beat, especially in the left lateral or prone position, emotional or physical activity caused by tachycardia , or ventricular premature beats can make the palpitations more obvious, because the pulse pressure is significantly increased, it is often felt that the body has a strong sense of arterial pulsation, especially the head and neck.

(2) Difficulty breathing: Labor dyspnea first appeared, indicating that the reserve capacity of the heart has been reduced. As the disease progresses, there may be a sitting breathing and paroxysmal nocturnal dyspnea.

(3) Chest pain: angina pectoris is less common than aortic valve stenosis. The occurrence of chest pain may be caused by excessive stretching of the ascending aorta or obvious enlargement of the heart during left ventricular ejection. There are also factors of myocardial ischemia, and angina pectoris may occur. During activity, and at rest, it lasts longer and has a poor response to nitroglycerin; the onset of angina at night may be due to a decrease in diastolic blood pressure caused by a slow heart rate during rest, which reduces coronary blood flow; There are also complaints of abdominal pain, presumably related to visceral ischemia.

(4) Syncope: When changing body position quickly, dizziness or dizziness may occur, and syncope is less common.

(5) Other symptoms are fatigued, activity endurance is significantly decreased, excessive sweating, especially in the presence of nocturnal paroxysmal dyspnea or nocturnal angina, hemoptysis and embolism are rare, and hepatic congestion can occur in advanced right heart failure. , tenderness, edema of the ankle, pleural effusion or ascites.

In acute aortic regurgitation, acute left ventricular dysfunction or pulmonary edema can occur rapidly due to increased left ventricular volume load, increased wall tension, and left ventricular dilatation.

Symptoms of aortic valve stenosis Common symptoms Heart murmur purpura shortness of breath Shortness of heart valve disease, acute feeding difficulties, pleural effusion, early contraction, sputum

1. Pathophysiology

Cases with a mild degree of aortic valve stenosis have little effect on the blood function of the heart, and the clinical symptoms are not obvious. When the area of the aortic valve is narrow from the normal 3cm2 to about 1/4 of normal, or 0.75cm2, That is, it has a significant adverse effect on hemodynamics. In order to prevent the obstruction of the valve, the left ventricle must increase the contractile force when the blood is sent into the aorta, prolong the systolic time limit, and cause the left ventricular pressure to rise, sometimes up to 40 kPa. (300mmHg), the left ventricle and aortic systolic pressure showed a step difference, the valve stenosis pressure gradient can reach 13.3-20kPa (100 ~ 150mmHg), so the left ventricular myocardium showed a high degree of central hypertrophy, but the left ventricular cavity Does not expand, when left ventricular failure begins, left ventricular end-diastolic pressure gradually increases, myocardial contractility is weakened, left ventricular systolic pressure is reduced, left ventricular-aortic transvalvular systolic pressure gradient is reduced, followed by left atrium, The pulmonary circulation and the pressure in the right ventricle also increase, and the left atrium, right ventricular enlargement, and cardiac hypertrophy occur. When the left ventricle contracts, blood flows through the narrow valve orifice to the aortic wall. Caused by thickening of the vascular wall of the ascending aorta, the aortic wall is affected by blood flow for a long time, the local blood vessels are fragile, and the ascending aortic stenosis can be gradually expanded, the left ventricle myocardium is hypertrophic, and the left ventricular systolic time is prolonged, and Increased left ventricular lumen tension leads to insufficient blood supply to the subendocardial myocardium, which can produce left ventricular myocardial fibrosis.

2, symptoms

Congenital aortic stenosis cases present clinical symptoms in neonatal and infancy, the valve is often highly narrow, the left ventricle is severely hypertrophy, the left ventricular cavity is small, and the subventricular membrane is extensively fibrotic, clinically showing the left heart. Failure, shortness of breath, sweating, difficulty in feeding, etc., sometimes shock and purpura, most children and adolescents often have no obvious symptoms, only to find a diagnosis of heart murmur, only to diagnose, the case of heavier stenosis can be It is weak, nausea and shortness of breath after work. It can cause angina or fainting after work. In some cases, sudden death can occur.

3, physical examination

Infants and young children often have pale skin, shortness of breath, weak pulse, low blood pressure and purpura. Due to decreased cardiac output, systolic murmur and left ventricular aortic transvalvular pressure difference are not significant, and carotid arteries in children and adolescents. The pulsation is strong, the heart sound zone is not enlarged, the apex beats strongly and may shift to the left and down. The aortic valve area has a loud systolic hair-like spray-type murmur, and can hear the early contraction of the contraction, often accompanied by Trembling and conduction to the carotid artery and apical region, a small number of patients can still hear the diastolic blow-like murmur caused by aortic regurgitation, the second heart sound in the aortic zone is delayed, weakened and split, and the systolic murmur is rhomboid on the heart sound map. Graphics.

Aortic valve stenosis examination

Chest X-ray

If the degree of stenosis is mild, chest X-ray examination may have no abnormal signs, and some cases may show ascending aorta enlargement and left ventricular hypertrophy. In case of heart failure, heart enlargement, lung field stagnation, and cases over 25 years old may be observed. Shows valve calcification.

Electrocardiogram

There are no abnormal signs in cases with early stage and less stenosis, and cases of severe stenosis can show left ventricular hypertrophy, strain and left atrial hypertrophy.

Cardiac catheterization

Increased left ventricular pressure, decreased aortic pressure, pressure gradient between left ventricular systolic pressure and aortic systolic pressure, mild stenosis at rest time pressure step does not exceed 5.3 kPa (40 mmHg); moderate stenosis pressure The step is 5.3 ~ 10kPa (40 ~ 75mmHg); more than 10kPa (75mmHg) is severe stenosis, the heart area can be calculated to calculate the valve area, the case size of severe stenosis is less than 0.5cm2 / m.

Selective left ventricular angiography and retrograde aortic angiography can show left ventricular wall hypertrophy, small left ventricular cavity, thickened valve, dome-shaped, contrast agent is injected into the aorta through a narrow valve orifice, and the ascending aorta exhibits a fusiform enlargement. In addition, valve activity, annulus size, and presence or absence of aortic regurgitation may be indicated.

Echocardiography

Sectional echocardiography can show symmetry hypertrophy of ventricular septum and posterior wall of left ventricle, thickening of aortic valve leaflets, widening of diastolic aortic valve closure line, perpendicular to the aortic wall, and reduced activity of systolic leaflet opening Small, the diameter of the stenosis can be determined from the diameter of the dome-shaped valve and the valve opening.

Diagnosis and differential diagnosis of aortic valve stenosis

Can be diagnosed based on clinical performance and laboratory tests.

Clinical aortic stenosis should be differentiated from systolic murmurs in the aortic valve area in the following cases:

(1) Hypertrophic obstructive cardiomyopathy: also known as idiopathic hypertrophic aortic subvalvular stenosis (IHSS), stimuli and systolic murmur in the fourth intercostal space of the left sternal border, rare systolic rash, aortic region The second heart sound is normal. Echocardiography shows asymmetry of left ventricular wall hypertrophy, ventricular septal thickening, and ratio of left ventricular posterior wall 1.3, systolic ventricular septum forward, left ventricular outflow tract narrowing, may be accompanied The anterior mitral valve leaflets are displaced to cause mitral regurgitation.

(B) aortic dilatation: seen in various reasons such as hypertension, aortic dilation caused by syphilis, can be heard in the second intercostal space on the right sternal border and short systolic murmur, the second heart sound in the aortic area is normal or hyperthyroidism, Without a second heart sound split, echocardiography can confirm the diagnosis.

(3) Pulmonary stenosis: a second rib septum on the left sternal border and a rough systolic murmur, often accompanied by a systolic click, the second heart sound in the pulmonary valve area is weakened and split, and the second heart sound in the aortic valve area is normal. The right ventricular hypertrophy is enlarged, and the trunk of the pulmonary artery is narrowed and expanded.

(D) tricuspid regurgitation: the lower left sternal border of the lower edge of the stimuli and high-profile full systolic murmur, increased blood volume during inhalation can increase the noise, weakened during exhalation, jugular vein beat, liver enlargement, right atrium and The right ventricle is significantly enlarged, and echocardiography confirms the diagnosis.

(5) mitral regurgitation: apical systolic murmur in the apical region, conduction to the left underarm; after inhalation of isoamyl nitrite, the murmur is weakened, the first heart sound is weakened, the second heart sound of the aortic valve is normal, and the aorta The valve has no calcification.

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