Pulmonary blood flow is high
Introduction
Introduction The length of life of patients with tricuspid atresia is closely related to pulmonary blood flow. Pulmonary blood flow is close to normal, the longest survival period can be more than 8 years; many patients with pulmonary blood flow can only survive for 3 months after birth. Tricuspid atresia is a kind of cyanotic congenital heart disease, the incidence rate is about It accounts for 1 to 5% of congenital heart disease. In the cyanotic congenital heart disease, the fourth place was after the tetralogy of Fallot and the aortic dislocation. The main pathological changes were tricuspid atresia or tricuspid valve loss, patent foramen ovale or atrial septal defect, mitral and left ventricular hypertrophy, and right ventricular dysplasia.
Cause
Cause
In the normal development of the embryo, the endocardial pad fuses, and the atrioventricular tube is equally divided into two left and right nozzles and participates in the formation of the membrane ventricular septum and the closed atrial septum. It is generally believed that the fusion site of the endocardial pad before and after the embryonic period is biased to the right side, and the right ventricular septum is displaced to cause uneven separation of the atrioventricular septum. The occlusion of the right atrioventricular canal is followed by tricuspid occlusion.
Pathological anatomy: When the tricuspid atresia, 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 were not seen in the right atrium. At the bottom of the right atrium, the site of the original tricuspid valve was replaced by muscle tissue, accounting for 76%, 12% of the patients with film-like tissue, and 6% of the membranous tissue. There may be chord-like tissue attachment on the ventricular side of the leaf. Another 6% of the atrioventricular septum was blocked by attachment to the right ventricular wall leaflet tissue, which Vanpragh called the Ebstein type.
Vanpragh divides the disease into three types: 1 muscle type: 84%, showing fibrous depression. Microscopic examination of muscle fibers radiated 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 below the right atrium. The right atrial wall thickened and enlarged, the left atrium expanded, there was a patent foramen ovale between the atrium, atrial septal defect, and sometimes a single atrium. The right ventricle develops poorly, especially in the right ventricular inflow tract. When the pulmonary artery is atresia, the right ventricle is not visible. The right ventricular small diameter is only a few millimeters. The lower right ventricular cavity may have undeveloped papillary muscles. There may be ventricular septal defects of different sizes between the left and right ventricles, and the right ventricular cavity is also larger. A narrow, thin-walled right ventricular outflow tract is sometimes seen beneath the pulmonary valve. In a few cases, the right ventricle is missing or there is a small fissure in the right ventricular wall below the pulmonary artery. In a very small number of cases, the ventricles are misaligned, and 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 and the left ventricle on the right side develops poorly.
In the case of tricuspid atresia, the left and right atrial blood passes through the mitral valve, so the mitral valve is larger than normal and the valve shape is normal. But sometimes with 3 or 4 leaflets, and may ride across the ventricular septum, in some cases mitral regurgitation, the left ventricle tends to enlarge and hypertrophy. The mutual anatomic relationship between the aorta and the common pulmonary artery may be normal (type I) or right-handed dislocation (type II), and very few are left-lateral dislocation (type III). Pulmonary and pulmonary valves may be normal, but pulmonary valve stenosis, occlusion or stenosis may occur. Tricuspid atresia varies widely. Vlad is divided into three types according to the anatomical relationship of the aorta, I, II, and III. According to the patency of the pulmonary artery and the size of the ventricular septal defect, there are eight types.
Pathophysiology: Tricuspid atresia has 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 systemic venous pressure Elevation leads to hepatomegaly and right heart failure. 2 systemic venous blood and pulmonary vein oxygenation blood in the left atrium completely mixed to reduce the degree of arterial oxygen saturation, pulmonary circulation more blood flow may not appear purpura or mild purpura, pulmonary artery outlets are narrow, there is 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 expanding and presenting left heart failure. About 20% of patients with tricuspid atresia have purulent stenosis due to stenosis of the pulmonary artery. In other cases, normal or increased pulmonary blood flow may cause heart failure or pulmonary vascular obstructive disease. Patients with right-handed dislocations of the aorta, especially those with enlarged pulmonary arteries and aortic coarctation or dysplasia, can die of severe heart failure early in life. Pulmonary vascular obstructive lesions are aggravated, and pulmonary blood flow is gradually reduced, and purpura is gradually aggravated.
Examine
an examination
Related inspection
Lung ventilation imaging 99Tcm-DTPA lung epithelial cell permeability assay
[clinical manifestations]
(A) Symptoms The length of life of patients with tricuspid atresia is closely related to pulmonary blood flow. Pulmonary blood flow is close to normal, the survival period is up to 8 years, and the pulmonary blood flow is very large. After birth, it can only survive for 3 months. If the pulmonary blood flow is less than normal, the postnatal survival period is in the above two cases. between. 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. Cases with small septum in the room showed clinical systemic venous congestion, jugular vein engorgement, hepatomegaly and peripheral edema. Due to the small amount of blood in the pulmonary circulation, most cases can appear purpura from the neonatal period, and they are anxious after exertion, and can take the position of sputum or hypoxic fainting. The clubbing (toe) often occurs in patients over 2 years of age. In cases of increased pulmonary blood flow, the degree of purpura is reduced, but often there is shortness of breath, rapid breathing, prone to pulmonary infection, often present with congestive heart failure.
(B) signs of the left sternal rim can often hear pulmonary stenosis or ventricular septal defect caused by systolic hairy murmur, combined with patent ductus arteriosus can hear continuous machine-like murmur. Increased pulmonary blood flow can be heard in the middle of diastolic drum-like noise. In addition, there may be signs of hepatomegaly, edema, jugular vein engorgement, and pulmonary edema.
[Auxiliary inspection]
(1) 90% of cases of electrocardiogram examination are left-lateral deviation of the electric axis and dislocation of the aorta. The pulmonary axis is normal or right-biased. The anterior leads of the heart showed changes in left ventricular hypertrophy and T wave inversion. 80% of cases showed P wave height or widening and notch.
(2) X-ray examination of chest X-ray performance is quite variable. The heart shadow of patients with reduced pulmonary blood flow is normal or slightly enlarged, and the heart shadow of patients with increased pulmonary blood flow is significantly enlarged. Typical chest X-ray signs are the right edge of the heart is straight, the left heart is round, the apex is elevated, the heart is depressed, and sometimes the heart shadow is similar to the tetralogy of Fallot. The heart of the aortic dislocation can be egg-shaped. In the case of less pulmonary blood flow, the lung pattern was significantly reduced, and the lung congestion was seen in the lung congestion.
(3) Cardiac catheter and angiography The right heart catheter can enter the left atrium through the atrial septum, and the right atrial pressure is higher than the left atrium. The pressure difference is inversely proportional to the diameter of the atrial defect, the defect is small, and the pressure difference is large. The arterial blood oxygen content is reduced, and the blood oxygen levels of the left atrium, left ventricle, pulmonary artery, and aorta are the same.
(4) Selective right atrial angiography shows that contrast agent enters the left atrium, left ventricle, and then into the pulmonary artery and aorta from the right atrium. Below the heart shadow, the undeveloped triangle, the right ventricular window, is located between the right atrium, the left ventricle, and the diaphragm. Sometimes angiographic examination can show ventricular septal defect, right ventricular cavity and outflow tract and pulmonary artery. In addition, the relationship and location of the two great arteries can be displayed. Left ventricular angiography can determine the presence or absence of mitral regurgitation.
(5) M-mode echocardiography showed that the tricuspid curve disappeared. The four-chamber view failed to see the tricuspid echo, the echo of the interatrial septum was interrupted, and the echo of the upper part of the ventricular septum was interrupted. Echocardiography and Doppler examination revealed blood flow from the right atrium to the left atrium and then into the left ventricle. The amplitude of mitral valve activity increased, and the right atrium, left atrium, and left ventricular cavity increased, and the right ventricle was small or disappeared.
Diagnosis
Differential diagnosis
The length of life of patients with tricuspid atresia is closely related to pulmonary blood flow. Even if the tricuspid valve is locked, the pulmonary blood flow can be normal. So it should be distinguished!
