Tricuspid atresia

Introduction to tricuspid atresia Tricuspid atresia is defined as the absence of tricuspid and tricuspid valves, and there is no direct communication between the right atrium and the right ventricle. The malformation is essentially a special type of left ventricular ventricle double entrance, with only the left mitral valve bordering between the left atrium and the left ventricle, left ventricular hypertrophy and mitral annulus and right ventricular dysplasia. The vast majority of cases were atrial orthostatic and ventricular sac, with atrial septal defect or patent foramen ovale and ventricular septal defect; a few were atrial reversal and ventricular left iliac. The relationship between the ventricle and the aorta can be consistent and inconsistent; the pulmonary artery can be narrow, atresia, and normal. basic knowledge The proportion of illness: 0.001% - 0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: ascites arrhythmia

Cause of tricuspid atresia

(1) Causes of the disease

It is generally believed that in normal development, the endocardial pad is fused, and the atrioventricular tube is equally divided into two left and right orifices and participates in the formation of the membrane ventricular septum and the closed atrial septum, the tricuspid valve from the endocardial cushion. And right ventricular myocardium differentiated, in this process tricuspid dysplasia, leaflet degeneration, degeneration, lack of leaflet tissue, the valve hole is surrounded by fibrous tissue, closed, and ultimately lead to tricuspid atresia, (generally considered embryo Before and after the endocardial pad fusion site is biased to the right side, the right ventricular septum shifts to cause uneven separation of the atrioventricular septum, and the right atrioventricular canal occlusion will form a tricuspid atresia in the future.)

(two) pathogenesis

1. Pathological changes In about 90% of cases of tricuspid atresia, the tricuspid valve merges into a decidual membrane, the pulmonary trunk is poorly developed, and the atresia can also affect the right ventricular outflow tract and the pulmonary trunk, while the pulmonary valve is severely dysplastic. The right ventricle can be severely stunted to normal size, or even dilated, and the tricuspid valve has varying degrees of insufficiency.

In the autopsy of the tricuspid atresia, the left ventricle is often enlarged and hypertrophied, but the mitral valve is normal or enlarged. There have also been reports of mitral valve multi-valvular deformity, mitral valve mitral and mitral valve riding across development Incomplete right ventricle.

Tricuspid atresia usually includes the following malformations:

1 tricuspid occlusion, no right atrium between the right ventricle;

2 atrial septal defect or patent foramen ovale;

3 ventricular septal defect or patent ductus arteriosus.

Tricuspid atresia is congenital closure, there is no valve hole, only a small depression in the bottom of the right atrium, surrounded by muscle fibers, a few fibrous or membranous structures, 80% of the traffic in the heart chamber is a foramen ovale Unclosed, may also be atrial septal defect, or even a single atrium.

There are five types of right atrium and right ventricle connections for tricuspid atresia:

1 muscle type accounts for 76% ~ 84%, the muscle at the bottom of the right atrium, a small dimple near the side wall, directly across the left ventricle and no connection with the right ventricle;

2 diaphragm type accounts for about 8% to 12%, a closed diaphragm between the right atrium and the right ventricle;

3 valve type accounts for about 6%, there is an open valve at the junction of the right atrium and the right ventricle, but there are diaphragms and muscles underneath that completely separate the right atrium from the right ventricle to form a lock;

4Ebstein malformation accounted for about 6%, forming a locked tricuspid valve between the right atrium and the right ventricle;

5 endocardial pad defect type accounted for about 2%, the common atrioventricular valve atresia from right atrium to right ventricle.

Edward and Burchell first classified the tricuspid atresia into three types according to the relationship between the aorta, and then further classified into type Ia, type Ib, type Ic, type IIa, type IIb, type IIc, depending on the presence or absence of pulmonary atresia or stenosis. There are 8 types of type IIIa and IIIb. Among the cases of tricuspid atresia, type Ib, type Ic, type IIb, type IIc, and type IIIa are the most common.

Type I tricuspid atresia (69%): This type is characterized by normal vascular relationship, type Ia, pulmonary atresia; type Ib, pulmonary stenosis with small ventricular septal defect; type Ic, pulmonary stenosis with large ventricular septal defect.

Type II tricuspid atresia (27%): This type is characterized by complete type of large vessel transposition, type IIa, pulmonary atresia; type IIb, pulmonary stenosis with small ventricular septal defect; type IIc, normal pulmonary artery with large ventricular septal defect .

Type III tricuspid atresia (4%): Type III is characterized by corrective large vessel transposition, type IIIa, pulmonary stenosis; type IIIb, subaortic stenosis, with pulmonary atresia (ie Ia, IIa) Type), died in infancy, with pulmonary stenosis (Ib, IIb, IIIa), accounting for 70% of childhood cases, 100% of adult cases.

Tricuspid atresia may combine multiple heart and large vessel malformations. The traffic in the heart chamber always exists. The patent foramen ovale accounts for 80%, the rest is atrial septal defect, and 22% of patients have a left superior vena cava. Usually drained to the coronary sinus, occasionally drained directly to the left atrium, venous venous drainage and coronary artery malformation are less common, patients with congenital pulmonary artery dysplasia often with membranous tricuspid atresia, 20% tricuspid atresia patients combined Parallel auricles, may also be associated with aortic coarctation, dysplasia or atresia, aortic arch disconnection, aortic valve atresia.

2. Pathophysiology In patients with tricuspid atresia, systemic venous return blood can not directly enter the right ventricular cavity, the blood in the right atrium can only reach the left atrium through the heart room traffic, the left atrium becomes the body, the heart cavity of the pulmonary venous blood, The mixed blood enters the left ventricle through a relatively normal mitral valve orifice, and then exits the left ventricle through the normally connected aortic valve orifice and aorta. Therefore, all patients have varying degrees of arterial oxygen saturation reduction. The degree of reduction depends on the severity of pulmonary blood flow obstruction. If the blood flow in the lungs is normal or increased, and the blood flow to the pulmonary veins is normal or increased, the arterial oxygen saturation is only slightly lower than normal, and there is no clinical or mild cyanosis. If the blood flow in the lungs is reduced and the blood flow to the pulmonary veins is reduced, the arterial oxygen saturation is significantly reduced, 70% of hypoxemia occurs, and there are obvious cyanosis in the clinic. For example, the atrial septal defect is small, and the right to left shunt is limited. Severe venous hypertension and right heart failure occur.

Due to dysplasia of the right ventricle, the left ventricle alone bears the body, the pumping work of the pulmonary circulation, the left ventricle needs extra work to promote the blood flow of a large number of pulmonary circulation, and the continuous overload operation can lead to left heart hypertrophy, left heart failure, and pulmonary blood flow. In the reduced cases, the left ventricle only increases the volume load, and often does not produce heart failure. However, in cases of increased pulmonary blood flow, the left ventricle often increases due to chronic volume load, left ventricular end-diastolic volume increases, and myocardial contractile function decreases. Left ventricular enlargement, heart failure, if there is aortic coarctation or aortic disconnection, promote the development of left ventricular hypertrophy and heart failure.

The development of the right ventricle of the heart varies with the size of the ventricular septal defect and the degree of pulmonary stenosis. Generally, there are pulmonary stenosis and small ventricular septal defect. A small part of the blood enters the dysplastic right ventricle from the left ventricle through the ventricular septal defect, and then passes through the stenosis. Pulmonary artery into the lungs, reducing pulmonary blood flow, a small number of patients with only mild or no pulmonary stenosis, accompanied by large ventricular septal defect, more blood from the left ventricle into the well-developed right ventricle and pulmonary artery, so that the lungs Increased blood flow, a rare case is no ventricular septal defect, pulmonary valve atresia, the only passage of blood to the lungs is the patent ductus or bronchial artery.

Tricuspid atresia prevention

Tricuspid atresia is a complex cyanotic congenital cardiovascular malformation with very poor prognosis and short survival. 49.5% die within 6 months after birth, 66% die within 1 year, and a few can survive to 10 years old. Above, the type of lesion and the degree of hemodynamic abnormality are the factors that determine prognosis. The symptoms of bruising at birth are severe, and the shunt is less in the atrial septum or interventricular septum. 90% of the patients die within 1 year of age; the prognosis of pulmonary blood flow increases Better, but some patients died of heart failure at an early stage. More than 50% of patients who have undergone appropriate surgery can survive to 15 years of age. In a follow-up report of a group of Fontan surgery, the 5-year survival rate is 85. %, the 10-year survival rate is 78%, and the main causes of death are heart failure, arrhythmia, infection and reoperation. Currently, there is no effective preventive measure. The main clinical diagnosis is to distinguish it from other cyanotic congenital heart disease. In order to properly treat the child in time.

Primary prevention

Congenital heart disease is caused by environmental factors, genetic factors and the interaction between the two. The prevention of genetic factors mainly focuses on premarital examination, avoiding close relatives' marriage, and accepting genetic counseling. More importantly, it is to find ways to avoid and prevent it. Environmental factors such as viral infections, drugs, alcohol and maternal diseases that may cause adverse changes in genetic predisposition during pregnancy to break the interaction between environmental factors and genetic factors are the key to primary prevention.

2. Secondary prevention

(1) Early diagnosis: Early diagnosis of congenital heart disease can be divided into two steps.

1 fetal diagnosis: in the 16 to 20 weeks of pregnancy, amniotic fluid cell culture, chromosome analysis, genetic diagnosis and enzyme activity determination, amniotic fluid metabolites, special protein and enzyme activity, etc. The above examinations were performed by women's vaginal aspiration of villus at 8 to 12 weeks of gestation, which is of great value for congenital heart disease caused by single gene mutations and chromosomal aberrations.

2 Infancy diagnosis: A comprehensive physical examination should be performed on the babies born, especially the cardiovascular system should be carefully auscultated and found to be further examined by cardiac ultrasound.

(2) Early treatment: Once the fetal diagnosis of congenital cardiovascular malformation is confirmed in the fetal period, the pregnancy should be terminated in time. For some hereditary enzymes or metabolic deficiency diseases, relevant replacement therapy should be carried out early after birth, and the conditional hospital Gene therapy can be performed to prevent the occurrence of the corresponding disease.

3. Three levels of prevention

Once the congenital heart disease is clearly diagnosed, the fundamental method of treatment is to perform surgery to completely correct the cardiac vascular malformation, thereby eliminating the pathophysiological changes caused by the deformity. Those who have not been operated or temporarily unable to operate should avoid overwork according to the condition. In order to avoid heart failure, if heart failure occurs, anti-heart failure treatment, prevention and treatment of complications, patients with congenital heart disease in the implementation of invasive examination or treatment, including cardiac catheterization, extraction, tonsillectomy, etc., should be routinely applied antibiotics to prevent Infective endocarditis.

Tricuspid occlusion complications Complications ascites arrhythmia

Early complications after Fontan surgery in patients with tricuspid atresia have right heart failure, thoracic fluid exudation, hepatomegaly and ascites, most of which resolve within a week, but there is persistent pleural effusion, most of the postoperative patients with purpura disappear The activity ability was significantly enhanced. There were reports that the right heart catheterization was performed in the postoperative patients. The average right atrial pressure was 1.87 to 2.40 kPa (14 to 18 mmHg), and the arterial oxygen saturation was 87 to 92%. However, this operation still existed for a long time. Dynamic abnormalities such as heterogeneous valve dysfunction, long-term right atrial load increase, leading to enlargement of the right atrium, prone to arrhythmia such as atrial arrhythmia, but most cases have satisfactory results in the early stage.

Tricuspid atresia symptoms Common symptoms phenomenon jugular vein engorgement neonatal cyanosis pulmonary blood flow a lot of continuous machine-like murmurs newborn sputum qi sputum sputum sputum edema

(a) symptoms

There is no gender difference in the occurrence of tricuspid atresia. Tricuspid atresia accounts for 1% of congenital heart disease. In infants who die of congenital heart disease within 1 year after birth, tricuspid atresia accounts for 2.5%. Hairpin is the most common type. Clinical manifestations, occasional paralysis, cyanosis and more than 2 years old children often have clubbing, pulmonary blood flow reduction found on the first day after birth, 85% of patients were found within 2 months The start time of cyanosis is an indicator of the severity of pulmonary artery obstruction. It has prognostic value. 80% of those who have cyanosis in the neonatal period die within 6 months. About half of the patients have a history of hypoxia, occasional loss of consciousness, and tricuspid atresia. The length of life of the patient is closely related to the blood flow of the lung. The blood flow of the lung is close to normal. The survival period can be up to 8 years. The blood flow of the lung is usually only 3 months after birth. The blood flow is less than 6 months. In normal cases, the survival time after birth is between the above two situations. Keith et al reported that 50% of patients with tricuspid atresia can survive to 6 months, 33% survive to 1 year old, and only 10% can survive to 10 years. Small channel, clinically presented with systemic venous congestion, jugular vein Aggression, hepatomegaly and peripheral edema, due to less blood circulation in the lungs, most cases can appear purpura from the neonatal period, shortness of breath after exhaustion, and can take sputum position or hypoxic fainting, often more than 2 years old patients In the case of clubbing (toe), increased blood flow to the lungs, the degree of purpura is reduced, but often with shortness of breath, rapid breathing, prone to pulmonary infection, often with congestive heart failure, heart failure is important for tricuspid atresia One of the manifestations, such patients can be manifested as left heart failure or right heart failure, the former is mostly caused by increased pressure load, partly caused by capacity load weight gain, or both pressure load weight gain factors, and There is the involvement of the capacity load increase factor; the latter is mostly caused by the small or lack of room traffic.

(two) signs

At the time of physical examination, in addition to cyanosis, clubbing (toe), hepatomegaly, edema, jugular vein engorgement and pulmonary edema and other signs of heart failure, it can be seen that the apex beats to the left and down, the pulsation is enhanced, the range is increased, auscultation When the first heart sound of the apex is enhanced, it is a single sound; the second heart sound at the bottom of the heart is also a single sound; the left sternal border III-IV intercostal or the systolic jet murmur (the outflow tract is narrow), or smelling reflux Sexual murmur (ventricular septal defect); apex audible and short diastolic rumbling murmur (increased pulmonary blood flow, mitral stenosis); sternal left intercostal occlusion and continuous machine-like murmur (arterial patent ductus arteriosus), increased pulmonary blood flow can be heard in the middle of the diastolic drum-like noise.

(3) Pathological anatomy:

When the tricuspid valve is locked, the right atrium does not directly communicate with the right ventricle, and the left atrium is connected to the left ventricle through the mitral valve. The tricuspid valve tissue and the tricuspid valve hole are not seen in the right atrium, and the right atrium is at the bottom. The location of the original tricuspid valve was replaced by muscle tissue, which was the most common, accounting for 76%. The film-like tissue accounted for 12%, and the leaflet fused to the membranous tissue accounted for 6%. The fused leaflet ventricle side may be There is a sputum-like tissue attachment, and another 6% of the atrioventricular septum is blocked by attachment to the right ventricular wall leaflet tissue. Vanpragh calls it the Ebstein type.

(1) Muscle type

(2) Membrane type

(3) flap type

(4) Ebstein type

Anatomical classification of tricuspid atresia

Vanpragh divides the disease into three types:

1 Muscle type: 84%, showing fibrous depression, microscopic examination of muscle fibers radiating around,

2 membrane type: 8%, accompanied by juxtaposed auricles, showing transparent fibrous tissue,

3Ebstein type: 8%, a blind end pocket formed in the right ventricle of the room is located under the right atrium, the right atrial wall is thickened and enlarged, the left atrium is enlarged, there is a patent foramen ovale between the atrium, the atrial septal defect, sometimes a single Atrial, poor development of the right ventricle, especially in the right ventricular inflow tract, when the pulmonary artery is locked, the right ventricle is not visible, the right ventricular small diameter is only a few millimeters, the right ventricular cavity may have undeveloped papillary muscles, the left and right ventricles may There are ventricular septal defects of varying sizes. The right ventricle is also larger in larger defects. Sometimes a narrow thin-walled right ventricular outflow tract is seen under the pulmonary valve. In a few cases, the right ventricle is missing or small in the right ventricular wall below the pulmonary artery. In the fissure, in a very small number of cases, the ventricle is misaligned, the mitral valve rides over the displaced ventricular septum, and the right ventricle is the main blood-discharging function. In this case, the right ventricle on the left side of the heart develops better. The left ventricle on the right side is stunted.

In cases of tricuspid atresia, the left and right atrial blood passes through the mitral valve, so the mitral valve is larger than normal, the valve shape is normal, but sometimes has 3 or 4 leaflets, and may ride across the ventricular septum, and some Case of mitral regurgitation, left ventricular tend to enlarge and hypertrophy, the mutual anatomic relationship between aorta and common pulmonary artery may be normal (type I) or right-handed dislocation (type II), very few left-handed dislocation (type III) The pulmonary artery and pulmonary valve may be normal, but pulmonary valve stenosis, atresia or stenosis of the stenosis may occur. The tricuspid atresia is very different. Vlad is divided into three types according to the anatomical relationship of the aorta. According to the patency of the pulmonary artery and the size of the ventricular septal defect, there are eight types.

(1) type IA pulmonary atresia

(2) Type IB pulmonary dysplasia with ventricular septal defect

(3) IC type pulmonary artery normal with ventricular septal defect

(4) Type IIA pulmonary atresia

(5) Type IIB pulmonary valve or subvalvular stenosis

(6) Type IIC pulmonary artery enlargement

(7) Type IIIA pulmonary or pulmonary stenosis (8) Type IIIB subaortic stenosis

Keith typing method for tricuspid atresia

Pathophysiology: Tricuspid atresia produces three conditions for hemodynamics:

1 systemic venous blood return to the right atrium, must enter the left atrium through the atrial septal defect or the patent foramen ovale. If the defect is small, the increase in systemic venous pressure leads to hepatomegaly and right heart failure.

2 systemic venous blood and pulmonary vein oxygenated blood in the left atrium completely mixed to cause different degrees of arterial oxygen saturation decreased, pulmonary circulation blood flow may not appear purpura or mild purpura, pulmonary arterial stenosis, severe purpura,

3 right ventricular dysplasia, ventricular cavity is very small, so the left ventricle bears the ventricle function of both sides of the ventricle, often enlarges and presents left heart failure, about 20% of patients with tricuspid atresia due to pulmonary artery stenosis, clinical presentation Purpura, in other cases, normal or increased pulmonary blood flow may occur in heart failure or pulmonary vascular obstructive disease, a case of right aortic dislocation of the aorta, especially if the pulmonary artery is thick and accompanied by aortic coarctation or dysplasia, then In the early post-natal period, he died of severe heart failure, pulmonary vascular obstructive lesions aggravated, and pulmonary blood flow gradually decreased, and purpura also gradually increased.

The diagnosis of typical cases includes cyanosis soon after birth, electrocardiogram showing left ventricular axis, right atrium and left ventricular hypertrophy, X-ray chest showed lung ischemia, normal or slightly normal heart, combined with echocardiography, general The diagnosis can be confirmed. Cardiac catheterization and cardiovascular angiography are generally performed before the decision of the surgical plan. In addition to helping to diagnose, it can also understand pulmonary artery pressure, resistance and development of small blood vessels, which is valuable for determining treatment options.

Tricuspid occlusion check

1. X-ray examination Tricuspid occlusion of chest X-ray showed a variety of features, the positive position of the visible heart shadow is boot or oval, the characteristic is that the right edge of the heart is straight, often does not exceed the spine shadow, left edge morphology The blunt shape is slightly square, the apex is elevated, and the heart is sunken. If the vascular pedicle of the large vessel is narrow, the lateral slice shows that the leading edge of the heart is straight, far from the chest wall, the posterior edge overlaps the spine, and the vascular pedicle is narrow. The heart shadow of the aortic dislocation can be egg-shaped. In a few cases, the heart contour can be similar to the tetralogy of Fallot. In most patients, the heart shadow can be normal or slightly enlarged, the pulmonary blood flow is less, and the lung texture is reduced. Progressively increased, blood flow in the lungs increased, and lung texture increased.

2. Electrocardiogram The characteristic of ECG is left axis deviation, left ventricular hypertrophy and strain, which is very helpful for the diagnosis of tricuspid atresia. 80% of cases show P wave height or widening and notch, and right atrial hypertrophy is usually high. The sharp P wave, clinically, in the case of infants with cyanosis and electrocardiogram showing left axis and left ventricular hypertrophy, it is highly suspected to be tricuspid atresia, because in the case of tricuspid atresia, 90% have an electric axis Left-sided, and left ventricular hypertrophy, progressive progressive aggravation with time, pulmonary axis normal or right deviation.

3. Echocardiography Echocardiography is the main method for diagnosing tricuspid atresia. Through two-dimensional echocardiography, the anatomical features of the tricuspid valve can be accurately understood, and the presence or absence of atrial septal defect and ventricular septal defect can be determined. It can also accurately measure the size of the chamber and the cavity. The disease generally shows that the tricuspid curve disappears. The four-chamber view fails to see the tricuspid echo, the echo of the interatrial septum is interrupted, and the upper part of the ventricle is interrupted. Echo interruption, echocardiography and Doppler examination showed that blood flow from the right atrium to the left atrium and then into the left ventricle, the mitral valve activity increased, the right atrium, left atrium, left ventricular cavity increased, right ventricle Small or disappeared, in addition, through this examination to understand the relationship between left and right ventricular cavity and large blood vessels, to determine the presence or absence of pulmonary valve orifice and aortic valve stenosis, but also to diagnose combined malformations, such as patent ductus arteriosus, aortic atrophy Narrow, aortic dysplasia, aortic arch disconnection, aortic valve atresia.

Doppler echocardiography can observe the direction of blood flow in the heart chamber and large blood vessels, and measure the pressure gradient between the right ventricle and the pulmonary artery (or aorta) on both sides of the interatrial septum.

4. Magnetic resonance magnetic resonance can accurately reflect the size of the heart chamber, the shape of the aorta, the relationship of the atrioventricular connection, the positional relationship between the left and right ventricles and the aorta, which is helpful for distinguishing the type of tricuspid atresia, such as the typical three-pointed The occlusion of the right atrioventricular sulcus is deep and filled with fat. The magnetic resonance imaging shows a bright linear or triangular structure instead of the tricuspid valve. In the membranous or Ebstein malformation tricuspid atresia, the right atrial sulcus is compared. Light approximation is normal.

5. Cardiac catheterization and cardiovascular angiography for tricuspid atresia, cardiac catheterization and cardiovascular angiography can provide more information than echocardiography, generally should be classified as routine examination, right heart catheter can enter the left atrium through the lack of room The right atrial pressure is higher than the left atrium. The pressure difference is inversely proportional to the diameter of the atrial septum. The defect is small, the pressure difference is large, the arterial blood oxygen content is reduced, and the blood oxygen content of the left atrium, left ventricle, pulmonary artery and aorta is the same.

Cardiac catheterization and cardiovascular angiography are mainly diagnosed according to the following points:

1 right heart catheter can not enter the right ventricle from the right atrium, but can enter the left atrium, left ventricle through the heart room traffic;

2 Because the blood is mixed in the left atrium, the left atrium, left ventricle and main, pulmonary oxygen saturation are similar;

3 right atrial pressure is equal to or greater than left atrial pressure; 4 selective right atrial angiography.

6. Selective right atrial angiography shows that contrast agent enters the left atrium from the right atrium, the left ventricle, then the pulmonary artery and aorta, the left atrium, the left ventricle and the aorta are developed early, and the right ventricle is not immediately developed, causing the right position to be on the right. The ventricular part forms a sharp-pointed triangular translucent area, which is called the right ventricle "window hole". It is a characteristic manifestation of angiography. Sometimes angiographic examination can show ventricular septal defect, right ventricular cavity and outflow tract and pulmonary artery. In addition, two can be displayed. The relationship and location of the aorta, left ventricular angiography can determine the presence or absence of mitral regurgitation.

Diagnosis of tricuspid atresia

diagnosis

The disease presents clinical symptoms such as purpura, shortness of breath and fatigue. The electrocardiogram shows left axis and left ventricular hypertrophy. P wave is high and wide. It should be highly suspected that there may be tricuspid atresia, right heart catheterization and angiography, ultrasound. Cardiogram examination can clearly diagnose the disease.

Differential diagnosis

Need for tetralogy of Fallot, Ebstein malformation, aortic dislocation, pulmonary atresia with ventricular septal integrity, severe pulmonary stenosis with right ventricular dysplasia, tricuspid stenosis with ventricular septal defect, single ventricle with pulmonary stenosis, aortic transposition with Pulmonary artery stenosis, right ventricle double outlet and single ventricle were identified.

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