The heart is divided into the left and right hearts by the atrial septum, with each side divided into the upper atrium and the lower ventricle. The right heart is separated by the tricuspid valve (three leaflets) and the left heart is separated by the mitral valve (two leaflets). Normally, when the ventricles are diastolic, the mitral valve (tricuspid valve) opens and blood pressure flows from the left atrium (right atrium) into the left ventricle; when the ventricles are contracted, the mitral valve (tricuspid valve) closes and blood pressure enters the body circulation (pulmonary circulation) through the aortic valve (pulmonary valve). The basic function of the mitral valve is to allow blood to enter the left ventricle from the left atrium when open and to ensure that blood enters the aorta from the left ventricle when closed and does not return to the left atrium, which is equivalent to the role of a one-way valve. When mitral stenosis occurs, the valve opening is reduced and cannot open properly, which can block blood flow from the left atrium to the left ventricle, resulting in left atrial stasis and subsequent pulmonary stasis.
Rheumatic fever is the cause of the majority of mitral stenoses. Rheumatic fever infection and its sequelae cause thickening, contracture, stiffening, and calcification of the mitral valve leaflets and adherent fusion at the leaflet junctions, resulting in stenosis and restriction of leaflet motion. If the tendon cords and papillary muscle fibers below the valve are sclerotic and fused and shortened, the leaflets can be pulled downward to form a funnel shape, and the hard leaflets will lose their opening and closing function, which is often accompanied by mitral valve closure insufficiency. In addition to rheumatic fever, left atrial mucinous tumor can also cause obstruction of the mitral valve orifice, which has similar symptoms to mitral stenosis; there are also a few isolated congenital mitral stenoses in which the children are difficult to survive after birth; and a few mitral stenoses are due to degenerative changes in the elderly. This article focuses on the most common type of rheumatic mitral stenosis.
Normal mitral stenosis has an orifice area of 4-5 cm2 , and mild stenosis occurs when the orifice area is reduced to 2-2.5 cm2 , with symptoms appearing only after strenuous activity. An orifice area of 1.1 to 2.0 cm2 is considered moderate stenosis, and symptoms can occur after physical activity. A stenosis with an orifice area of 1.0 cm2 or less is considered severe, and symptoms can occur at rest. So, how can mitral stenosis be detected in time? For people without medical expertise, it is important to understand the symptoms associated with mitral stenosis.
Mitral stenosis patients due to the severity of stenosis, the speed of progression, living conditions, occupation, labor intensity and compensatory mechanisms, its clinical performance can be very different, the main clinical symptoms are.
(1) dyspnea: When mitral stenosis enters the stage of left atrial failure, it can produce different degrees of dyspnea. In the early stage, it only appears during heavy physical labor or strenuous exercise, and can be relieved with a little rest, often without drawing the patient’s attention. As the degree of mitral stenosis increases, later shortness of breath is felt even at rest, and there are often episodes of nocturnal paroxysmal dyspnea. As the disease progresses further, it is often impossible to lie down and requires semi-recumbent or seated breathing. These symptoms are often aggravated by infections (especially respiratory infections), tachycardia, emotional stress and atrial fibrillation.
(2) Hemoptysis: the incidence is about 15%-30%, mostly in patients with moderate or severe mitral stenosis, and can be in the following conditions.
(1) Massive hemoptysis: it is due to the rupture of bronchial veins in the submucosa of the bronchus. Because of the presence of collateral circulation between the pulmonary veins and the bronchial veins, the sudden increase in pulmonary venous pressure can be transmitted to the small bronchial veins, causing the latter to rupture and bleed. The hemorrhage can reach hundreds of milliliters and is rarely caused by hemorrhagic shock because the decrease in pulmonary venous pressure often terminates on its own after hemorrhage, but one must be alert to asphyxia due to hemoptysis. Hemoptysis due to mitral stenosis occurs more often in the early stages of pulmonary stasis and is not a manifestation of pulmonary hypertension.
(ii) Stasis hemoptysis: it is often a small amount of hemoptysis or blood in sputum due to rupture of endobronchial microvessels or interalveolar capillaries.
③Pink foamy sputum: a characteristic manifestation of acute pulmonary edema combined with alveolar capillary rupture.
④Pulmonary infarct hemoptysis: mitral stenosis, especially in those who are bedridden for a long time and atrial fibrillation, can cause pulmonary artery embolism and hemoptysis due to dislodged thrombus in the vein or right atrium, often presenting as gelatinous dark red sputum.
(5) Chronic bronchitis with blood in sputum: Bronchial mucosa is often edematous in patients with mitral stenosis, which can easily cause chronic bronchitis.
(3) Cough: Unless combined with respiratory tract infection or acute pulmonary edema, the cough is mostly dry, mostly at night or after labor, because of increased venous reflux, which aggravates pulmonary stasis and causes cough reflex; sometimes the left atrium, which is obviously enlarged, compresses the left bronchus and causes irritating dry cough. Pulmonary stasis and bronchial mucous membrane edema and exudation, coupled with reduced ciliary function of bronchial mucous membrane epithelial cells, can easily cause bronchial and pulmonary infections, at which time there can be coughing sputum. Rapid atrial fibrillation can induce acute pulmonary edema, causing dyspnea or aggravating it in patients who were asymptomatic, and forcing them to seek medical attention.
(5) Severe mitral stenosis often has a “mitral face,” in which the patient has purplish-red cheekbones and mildly cyanotic lips.
(6) Other.
(1) fatigue and weakness: reduced cardiac output due to mitral stenosis.
(2) Dysphagia: caused by compression of the esophagus by the enlarged left atrium.
③If the left atrial appendage thrombus is dislodged: it can cause arterial (cerebral and visceral) embolism symptoms.
④When the right heart is involved resulting in right heart failure: due to gastrointestinal stasis and dysfunction, it can cause loss of appetite, and due to liver stasis and decreased liver function it can cause pain in the liver area, liver enlargement, abdominal distension, lower limb edema, and wasting.
Therefore, when you have symptoms similar to those mentioned above, please recall whether you have a history of rheumatic fever with high fever and sore throat when you were young; if you are a woman, you should be more concerned about whether you have rheumatic mitral stenosis, because women account for 2/3 of patients with rheumatic mitral stenosis.
If you have been diagnosed with mitral stenosis, you will need a clear treatment plan.
(1) Compensated phase.
(1) Prevention of rheumatic activity and treatment of streptococcal infection of the throat.
(2) Avoid strenuous activities and heavy physical work. Some data show that when the heart rate increases from 70 beats/min to 80 beats/min during activity, the atrioventricular transvalvular pressure difference can be increased by 1 times.
(3) Pay attention to the combination of work and rest, and the diet should be light and rich in vitamins to keep the heart function in the compensatory phase for a longer period of time to slow down the progress of the disease.
(2) Decompensated stage.
①Appropriate rest, restrict water and sodium intake, give cardiac and diuretic drugs; ②If combined with paroxysmal atrial fibrillation, give amiodarone to control its attacks; ③The combined left atrial thrombosis should be given antiplatelet and anticoagulation therapy.
Drug therapy can only temporarily reduce the symptoms, but cannot cure and control the progress of the disease, to completely relieve the symptoms, it is necessary to lift the valve stenosis.
For asymptomatic patients or those with class I heart function, observation and follow-up are recommended, and surgery is not recommended. In symptomatic patients with simple mitral stenosis in class II or higher with milder lesions (septal or septal thickening lesions), percutaneous balloon mitral valve dilatation (PBMV) or surgical closed dilatation (now rarely used and largely replaced by PBMV) can be considered to achieve a higher quality of survival over a longer period of time.
Surgery is indicated for the following types of patients.
①Symptomatic mitral stenosis and/or combined pulmonary hypertension, with cardiac function grade II or higher should be treated surgically.
②Severe cardiac insufficiency should be treated surgically if the symptoms are improved by medication or if the condition is super stable.
(③) cardiac function grade Ⅲ to Ⅳ by medical treatment is ineffective or the condition gradually aggravated, should be early surgical treatment.
④In cases of combined bacterial endocarditis, surgical treatment should be performed after infection control of 4-6W. If drug treatment is ineffective and it is difficult to control heart failure, emergency surgery can be performed.
⑤ In case of rheumatic activity, surgery should be performed after 3 months of control.
(6) If embolism of body or pulmonary circulation has occurred recently, surgery should be performed after 1 to 2 months.
(7) If embolism of the terminal artery occurs again, surgery should be performed electively even if there are no symptoms.
(8) Pregnant patients with mitral stenosis should strive for surgical treatment in early pregnancy when the cardiac function is grade II to III. If acute left heart failure occurs in the second and third trimesters of pregnancy, emergency surgery should be performed.
⑨ For severe mitral valve lesions, severe lesions of the valve and subvalvular structures, severe fibrosis, contracture, and calcification, combined with mitral valve closure insufficiency and inability to perform valvuloplasty, mitral valve replacement is required.
When it comes to mitral valve replacement, it is important to talk about prosthetic valves. Currently, there are two types of prosthetic valves, mechanical and biologic, and choosing which valve to use is a headache for many patients. The following is a brief description of the advantages and disadvantages of mechanical and biologic valves, in the hope that it will help you and that you will be able to make a preliminary decision about which valve to replace when you are hospitalized.
The advantages of mechanical flaps are
1, durable, as long as the valve is well maintained in the body, except for individual cases of valve failure due to some factors (commonly known as “stuck valve”), generally can be used for 40-50 years, for the average patient, eliminating the need for reoperation.
2, for patients with combined atrial fibrillation, no special treatment is needed for atrial fibrillation.
3, the price is cheaper than biological flaps.
Disadvantages are.
1.Noisy, some patients can hear the “ticking” sound of the mechanical valve with the heartbeat.
2, the hemodynamics of the valve is relatively poor compared to the biological valve, but the size of the valve is suitable, and there is no significant impact on cardiac function.
3. Long-term anticoagulation with oral anticoagulant drugs (Warfarin) is required, and regular (more frequent) blood tests at medical institutions are needed to ensure that the coagulation mechanism is within the normal range.
The advantages of the biologic flap are.
1, 6 months after the replacement of the biological valve can be free of anticoagulant drugs, eliminating the tediousness of daily medication and regular medical institution blood sampling and laboratory tests, and having a higher quality of life.
2, hemodynamics closer to the body’s own valve, no noise.
3, less prone to mechanical failures such as flap failure, resulting in emergency life-threatening situations.
Disadvantages are.
1, not durable, because for the human body, the biological flap is a foreign tissue, will be attacked by the body’s immune system, will slowly calcify and destroy, for patients over 60 years of age, the average use of 15-20 years, the younger the patient, the shorter the use of biological flap, for patients aged 10-20 years, the average use of only 5-10 years, biological flap destruction requires a second surgery to replace, the risk of surgery higher surgical risk.
2, the biologic flap production process is complex, the current model is limited, and for patients with too small an annulus no biologic flap of the same size is available.
3, for patients with combined permanent atrial fibrillation, oral anticoagulant drugs are still needed to prevent atrial fibrillation thrombosis after replacement of the bioprosthesis, which is of little significance for improving quality of life.
4, the price is relatively high.
Therefore, in general, because of the disease spectrum, medical level, and medical insurance system in China, most patients suffering from rheumatic mitral stenosis are suitable for replacement of prosthetic mechanical valves, while for patients who are
1, elderly patients over 65 years of age who do not have combined atrial fibrillation.
2, female patients of childbearing age who have a strong desire to have children and can bear the risks and costs of future secondary surgery.
3. Patients who do not have the ability to check coagulation and can bear the risk and cost of another or even multiple surgeries.
4. Patients who cannot accept daily medication and regular blood tests to monitor coagulation and can afford the risk and cost of another or even multiple surgeries may be considered for replacement of the bioprosthetic valve.
Finally, I hope this article can be helpful and I wish all patients with rheumatic mitral stenosis a speedy recovery.