Pediatric complete pulmonary venous connection
Introduction
Introduction to complete pulmonary venous connection in children Complete pulmonary venous connection refers to the access of the right atrium to all pulmonary veins directly or through the body vein, accounting for 1.5% to 2.6% of all cardiovascular malformations. Anomalous pulmonary connection (anomalous pulmonary venous connection), also known as abnormal pulmonary venous return (anomalous pulmonary venous return), refers to the pulmonary veins connected directly or through the venous route to the right atrium. All pulmonary veins connected to the right atrium directly or through the body vein are called total anomalous pulmonary connection (TAPVC). One or several pulmonary veins but not all pulmonary veins are connected directly or through the body vein to the right atrium. Pulmonary vein connection abnormality (partialanomalous pulmonaryvenous connection, PAPVC). basic knowledge The proportion of illness: 0.0001-0.0003% Susceptible people: children Mode of infection: non-infectious Complications: heart failure, pulmonary edema, multiple lung infections
Cause
Complete pulmonary venous connection in children
(1) Causes of the disease
In the early stage of embryonic development, the pulmonary vascular bed is connected with the total main vein and the umbilical yolk sac venous system. Later, the right common main vein is derivatized into the right superior vena cava, the azygous vein, and the left main main vein is deduced into the left superior vena cava. The coronary sinus and the umbilical yolk sac venous system are derived into the inferior vena cava, venous catheter, portal vein, etc., and there is no direct connection with the original heart during the 25th to 27th day of pregnancy. In the later development, the pulmonary vein is apart from the bronchial vein. Keeping the connection, the connection with the main vein, the yolk sac venous system disappears, and finally the pulmonary vein is fused to the original atrium. The connection between the pulmonary vein bed and the total main vein and the umbilical yolk sac venous system still exists. Lead to the common pulmonary vein fusion in the right atrium or pulmonary total venous dysplasia, without fusion with the original atrium, can cause abnormal pulmonary vein connection, pulmonary venous blood to the left main main vein leading to pulmonary vein and left superior vena cava, coronary sinus connection, pulmonary venous blood The main main vein is connected to the right superior vena cava, the azygous vein, and the pulmonary vein is connected to the umbilical yolk sac vein. Different types of pulmonary vein connection abnormalities are formed by intravenous, venous catheter or inferior vena cava connection, pulmonary total vein atresia or the extent and timing of dysplasia of the original left atrium.
(two) pathogenesis
1. There are many classification methods for pathological anatomy of complete pulmonary vein connection abnormalities. There are classifications according to the length of abnormal channels (Burrough and Edwards), and also according to embryo and anatomy (Neill), which is connected to the left main main vein and the right main main vein. The yolk sac vein is generally classified according to the anatomic site of abnormal connection (Darling et al):
(1) supra-type: this type is the most common, accounting for 1/2 of the complete pulmonary vein connection abnormalities. The left and right pulmonary veins first merge into the common pulmonary veins behind the left atrium, passing the abnormal vertical vein through the left pulmonary artery and the left upper bronchus. Left unnamed vein connection, confluence to the right superior vena cava, right atrium, connected with left unnamed vein accounted for about 44%, vertical vein and right superior vena cava directly connected (rare (11% to 15%), combined with other cardiac malformations .
(2) Heart type: about 30%, the pulmonary veins are connected to the right atrium through a short duct or 3 to 4 holes or the pulmonary veins are connected with the coronary sinus, and the coronary sinus is enlarged but the position is normal.
(3) Subcardiac type: about 13% to 24% of the complete pulmonary vein connection abnormality. The left and right pulmonary veins are connected to the descending vertical vein respectively, and pass through the esophageal hiatus of the diaphragm in front of the esophagus, parallel to the inferior vena cava. And the abdominal aorta and the downward movement between the two, the most common (70% to 80%) is connected to the portal system, and the connection with the venous catheter, hepatic vein or inferior vena cava is rare.
(4) Mixed type: rare, accounting for 5% to 10%, there are two or more abnormal connection points of pulmonary veins. The most common is the left pulmonary vein connected with the left innominate vein, the right pulmonary vein and the right atrium or coronary artery. Venous sinus connection, most combined with other cardiac malformations, pulmonary venous obstruction can occur in all types of complete pulmonary vein connection abnormalities, common pulmonary veins are their own narrow stenosis, in the heart type, subcardiac type cases can also be seen external obstruction caused by obstruction, such as heart Inferior, the venous return channel can be externally compressed when passing through the esophageal hiatus. The descending vertical vein and portal vein junction and the narrow venous catheter can block the pulmonary venous return. The subcardiac reflux obstruction is more common, and the supraventricular complete pulmonary vein connection. An abnormal vertical vein rises between the left pulmonary artery and the left bronchus, or the vertical vein that flows into the right superior vena cava rises between the right pulmonary artery and the bronchi, and can be compressed and narrowed, and the vertical vein is connected to the left innominate vein. There may also be stenosis, and the most common type of obstruction in the heart type is seen.
2. Pathophysiology Complete pulmonary vein connection abnormality In addition to pulmonary vein abnormalities, it also includes atrial-level right-to-left shunt, such as patent foramen ovale, atrial septal defect, hypoxic degree of systemic vein when complete pulmonary vein connection is abnormal. Blood and pulmonary veins containing more oxygen in the right atrium mixed, if the heart room traffic is restricted, blood flow into the left atrium is limited, causing insufficient circulation of the systemic circulation, while the right atrial pressure is increased, the body vein and pulmonary venous return are blocked; The gap between the rooms is large, and the right and left are divided smoothly.
The blood flow from the right atrium to the right ventricle and the left atrium depends on the atrium, ventricular compliance and body, resistance to the pulmonary circulation, right atrium, right ventricle and pulmonary artery are enlarged due to increased blood flow, while the left atrium and left ventricle are Due to decreased filling, volume reduction, hemodynamic changes in complete pulmonary vein connection abnormalities are closely related to the presence or absence of pulmonary venous obstruction. In non-obstructive type, with the gradual decline of pulmonary vascular resistance after birth, the blood of the body vein and pulmonary veins enters the pulmonary circulation. The blood flow is correspondingly increased, and the hemodynamic changes are similar to those of the large atrial septal defect. The right ventricular volume is overloaded, causing right ventricular enlargement, cardiac hypertrophy, pulmonary artery pressure is significantly elevated, and obstructive complete pulmonary vein connection is abnormal, pulmonary vein Total dry obstruction and pulmonary arteriolar hypertrophy, intimal hyperplasia, increased lymph in the lungs, lymphatic dilatation leading to pulmonary edema, secondary pulmonary hypertension, right ventricular pressure, eventually leading to right heart failure.
Prevention
Complete pulmonary venous connection prevention in children
The occurrence of congenital heart disease is a comprehensive result of various factors. In order to prevent the occurrence of congenital heart disease, publicity and education of popular science knowledge should be carried out, and key populations should be monitored to give full play to the role of medical staff and pregnant women and their families.
1. Get rid of bad habits, including pregnant women and their spouses, such as smoking, alcohol and so on.
2. Actively treat diseases affecting fetal development before pregnancy, such as diabetes, lupus erythematosus, anemia, etc.
3. Actively do prenatal checkups to prevent colds. Try to avoid using drugs that have been proven to have teratogenic effects and avoid contact with toxic and harmful substances.
4. For older women, there is a family history of congenital heart disease, and one of the couples with serious diseases or defects should be monitored.
Complication
Complete pulmonary venous connection complications in children Complications heart failure pulmonary edema multiple lung infection
Nutritional disorders, growth retardation, repeated lung infections, and can cause heart failure, pulmonary edema.
Symptom
Pediatric complete pulmonary venous connection symptoms common symptoms purpura heart malformation heart murmur clubbing (toe) lifting pulsation slow growth heart enlargement right heart failure shortness of breath
The patient's symptoms depend on the presence or absence of obstruction of the pulmonary veins, the size of the heart chamber and other co-existing cardiac malformations. Pulmonary hypertension and right heart failure occur early in the heart chamber. The symptoms develop rapidly and the disease is severe. The lungs are not obstructed. Larger pulmonary hypertension occurs later, but cyanosis is obvious, the disease develops slowly, the baby grows slowly, the breathing is short, the heart beats and the mild cyanosis, and is misdiagnosed as pneumonia and respiratory distress syndrome, the physical examination can be no specific noise, sometimes In the second intercostal space of the left sternal border, there is a squeezing hair-like jet-type murmur. The second sinus of the pulmonary valve has a split and hyperthyroidism. The left lower edge of the sternum may hear a diastolic rumbling noise, and the heart sound zone is enlarged. Lifting pulsation, the clubbing (toe) is generally lighter.
Examine
Examination of complete pulmonary venous connection in children
In the case of pulmonary infection, bloody infections, white blood cell counts, and neutrophils were significantly increased.
Chest X-ray
(1) non-obstruction type: right atrium, right ventricle enlargement, increased pulmonary blood, such as connected to the left innominate vein, left vertical heart can be seen dilated vertical vein and left innominate vein, right side can be seen in the superior vena cava, so that the heart shadow The typical "8" shape or snowman-like appearance is more common in older children, and the image of children born for several months is not obvious.
(2) Obstructive type: The chest radiograph is characterized by diffuse spotted reticular shadow of the interstitial lung, which is radiated from the hilar to the surrounding area. When the interstitial lung and alveolar edema are severe, the ground glass can be changed, and the heart is not clear, but the heart Do not increase (Figure 2), X-ray only in the neonatal period, the heart failure, but the heart is not big, it is diagnostic.
2. Electrocardiogram electric axis right deviation, right ventricular hypertrophy, children without pulmonary venous obstruction, may be associated with right atrial enlargement, manifested as II lead and right chest lead P wave high tip.
3. Echocardiography When the examination showed that the right atrial volume was overloaded, there was a right-to-left shunt in the foramen oval or atrial septum, and there was no normal refluxing pulmonary vein in the left atrium. The left atrium, the left ventricle were small, and the interatrial septum was In the case of left bulging, a complete diagnosis of complete anomalous pulmonary venous connection is required. The purpose of echocardiography is to determine the number of ectopic pulmonary veins, obstruction sites, and pulmonary artery pressure. When the pulmonary artery velocity is high, pulmonary trunk dilatation can be seen.
(1) supra-type: the left and right pulmonary veins are separated from the left atrium by the coronal section of the xiphoid process. The vertical veins that are walking up are most visible in the upper sternal fossa (Fig. 3A). The pulse Doppler can detect the vertical vein. To the blood flow spectrum and the negative blood flow in the superior vena cava, if the vertical vein walks between the left pulmonary artery and the left bronchus, it can be observed through the sagittal section of the xiphoid.
(2) Intracardiac type: The coronal section of the xiphoid can be seen in the pulmonary veins or into the right atrium after aggregation, such as pulmonary venous ectopic drainage into the coronary sinus, the section can also see coronary sinus enlargement (Fig. 3B), which requires Identification of large atrial septal defect (the primary atrial septal defect is located in a more advanced section).
(3) Subcardiac type: the left and right pulmonary vein collection cavities are also seen through the coronal section of the xiphoid process, and then a vein is seen below the sacral sagittal section through the diaphragm, and the venous total is seen through the color Doppler imaging. The esophageal hiatus is narrow, and the blood flow is traced to the portal vein or hepatic vein (Fig. 3C). The portal vein is often dilated.
(4) Mixed type: comprehensive evaluation of multiple sections is required. The most common mixed type complete pulmonary venous connection is the right pulmonary vein directly into the right atrium, and the left pulmonary vein is connected to the left innominate vein through the vertical vein.
Pulmonary venous obstruction can be estimated by continuous Doppler and color Doppler imaging. The turbulent blood in the stenosis shows a multicolored blood flow signal, the blood flow velocity at the obstruction site increases, and there is no phase blood flow map, but if the right ventricular outflow tract Obstruction, pulmonary venous blood flow is insufficient, the above phenomenon may be masked, common in complex cyanotic heart disease, prostaglandin E can be identified, tricuspid regurgitation detector can be used to measure the pressure gradient on both sides of the tricuspid valve And then clear the pulmonary artery pressure.
4. Cardiac Catheterization For most patients, two-dimensional echocardiography and Doppler techniques can be used to understand the details of the venous anatomy and obstruction of the pulmonary vein. Cardiac catheterization is rarely performed. Cardiac catheterization is only used for complex cases and stenotic vessels. Precise positioning.
(1) Blood oxygen saturation: The blood oxygen saturation at the entrance of the pulmonary vein is significantly increased.
(2) Pressure: Beware that the room traffic is very small, the right atrial pressure is often higher than the left atrium, but without this difference in pressure, the existence of restrictive atrial traffic cannot be ruled out, and the right ventricle and pulmonary artery pressure is slightly higher than the systemic circulation.
(3) angiography: Selective pulmonary venography has a diagnostic value for clearing the abnormal position of the pulmonary vein. In obstructive children, vascular stenosis can be shown and the contrast emptying time is prolonged. However, due to the placement of the cardiac catheter in the pulmonary venous return channel, The degree of obstruction can be further increased, and this test is more dangerous in infants with pulmonary venous obstruction and pulmonary hypertension.
5. Magnetic resonance imaging of ectopically connected pulmonary veins and reflux vein stenosis can also be shown by magnetic resonance, but there is a certain risk of placing the baby on magnetic resonance instruments, and no research has shown magnetic resonance imaging. Better than the above diagnostic methods.
6. CT and MRI CT and MRI can well display and diagnose abnormal connection of pulmonary veins. The contrast-enhanced magnetic resonance angiography sequence is the best for the diagnosis of pulmonary vein abnormal connection. The multi-angle maximum density projection reconstruction can be from sagittal and coronal And multiple angles such as transverse position show direct signs of abnormal connection of pulmonary veins. It is helpful to determine the type of abnormal connection of pulmonary veins and whether there is obstruction. If there is obstruction in complete pulmonary vein abnormal connection, the choice of imaging diagnosis method is very large. Impact, although cardiovascular angiography is the gold standard for diagnosis, but for traumatic examination, injection of contrast agent in the pulmonary artery, even non-ionic contrast agents can induce or aggravate pulmonary edema, there is a certain risk, after pulmonary angiography There is a decrease in arterial oxygen saturation and a slow emptying of the contrast agent in the pulmonary capillary network. In the non-invasive examination method, spiral CT diagnosis and multi-slice spiral CT can well display and diagnose abnormal connection of pulmonary veins, but CT also requires The use of iodine-containing contrast agents, complete pulmonary vein abnormalities such as obstruction, CT examination is also a certain risk, in addition to CT before the test It is helpful to diagnose the subcardiac type of complete pulmonary vein abnormal connection. CT examination generally does not scan the abdomen and may miss the diagnosis. In comparison, CE-MRA diagnoses abnormal pulmonary vein connection, pulmonary vein and body vein are clear, and no iodine-containing contrast agent is used. There is no risk of inducing or aggravating pulmonary edema, and the diagnosis of abnormal connection of pulmonary veins is more accurate and safer.
CT and MRI examinations can also clearly show the right atrial enlargement, right ventricular enlargement, pulmonary artery dilatation, relatively small left ventricle, etc., which are helpful for the diagnosis of abnormal pulmonary vein connection, and the interventricular septum associated with abnormal pulmonary vein connection. Defect, coronary sinus enlargement, left vertical vein, left innominate vein and right superior vena cava dilatation can also be displayed well, and can also show the positional relationship between the transverse vein and the left heart chamber. Multi-slice spiral CT has coronary sinus No expansion can show the best.
7. Cardiovascular angiography Anomalous pulmonary angiography can be used for selective pulmonary angiography or selective pulmonary venography. Both methods can achieve better diagnostic results. In general, complete pulmonary venous anomalies are connected with selective pulmonary angiography. More selective partial pulmonary venous angiography with selective pulmonary venography. Both pulmonary angiography and pulmonary venography were based on orthotopic angiography. The catheters were all NIH catheters. Selective pulmonary venography was used to detect abnormal catheters. After the head is fully freed, the contrast agent is injected at a rate of 5-8 ml per second at a dose of 0.5-1.0 ml/kg. The tip of the selective pulmonary angiography catheter is located at the common pulmonary artery, left pulmonary artery or right pulmonary artery at a rate of 15 ml per second. Contrast agent injection, the dose of 1.5ml / kg, but for the obstructive pulmonary vein abnormal connection, the amount of contrast agent should be reduced as appropriate, digital subtraction angiography (DSA), to improve the diagnostic effect of selective pulmonary angiography, DSA The image after the injection of the contrast agent is subtracted from the image before the injection of the contrast agent, and the remaining image represents only the injection. The contrast agent in the heart chamber and blood vessels eliminates the overlapping shadows of the existing bones and soft tissues, and the image is clearer, which can better display the ectopic drainage of the pulmonary veins, and appropriately take some images without contrast agent, and select them patiently. The subtraction of the image of the same respiratory phase helps to improve image quality.
Any congenital heart disease should be observed when observing the pulmonary venous return. For those suspected and connected with abnormal pulmonary veins, each pulmonary venous return should be observed. It should be observed whether there is a vena cava, coronary sinus and right. The atrium develops in the left atrium and slowly replays the cardiovascular imaging film or digital film to help understand which heart cavity is first developed. For complete pulmonary vein abnormal connection, it is also necessary to observe whether the four pulmonary veins merge into one pulmonary vein (co-cavity). The morphology of the pulmonary veins and how the pulmonary veins continue to flow back. The blood of the pulmonary veins flows into the left vertical vein, then the left vertical vein, the left innominate vein, and the right superior vena cava dilate as if flowing into the right superior vena cava, only the right superior vena cava dilates; The sinus, the coronary sinus dilatation, is egg-shaped shadow, located on the transverse iliac crest, the center of the heart shadow; if the flow entry vein, you can see the vertical vein walking down (Figure 9), the pulmonary vein abnormal connection should also be connected with cardiovascular imaging Pay attention to the presence or absence of pulmonary venous return obstruction, supraventricular complete pulmonary vein abnormality connected with left vertical vein The most common obstruction site spans the left main bronchus in the left vertical vein. Obstruction can occur due to compression of the left pulmonary artery and the left main bronchus. Secondly, obstruction can also occur at the junction of the left vertical vein and the left innominate vein. Pulmonary vein abnormalities connected to the ectopic drainage of the pulmonary vein can enter the portal vein system, but also enter the inferior vena cava system, etc., where the pulmonary vein abnormal connection to the portal vein system is more common, the abnormal connection of the pulmonary vein into the inferior vena cava system can be obstructive or Non-obstructive, but the abnormal connection of the pulmonary veins to the portal vein system is obstructive. Subcardiac type of complete pulmonary vein abnormal connection can often cause obstruction due to compression of the vertical vein through the diaphragm. Even if there is no stenosis in the vertical vein, the abnormal connection of the pulmonary vein is abnormal. The venous system is still obstructive, because the blood flow from the portal vein must pass through the capillary network of the hepatic sinus to the hepatic vein and the inferior vena cava, and the capillary network of the hepatic sinusoid constitutes an obstruction.
Diagnosis
Diagnosis and diagnosis of complete pulmonary venous connection in children
The examination items for the diagnosis of complete anomalous pulmonary venous connection include chest X-ray, electrocardiogram, Doppler echocardiography, nuclear magnetic resonance and cardiac catheterization, among which chest X-ray, electrocardiogram and Doppler echocardiography It is necessary to check the items. MRI and cardiac catheterization can be selected according to the condition of the child. Chest X-rays of complete pulmonary venous connection show heart enlargement and pulmonary congestion. Electrocardiogram shows right axis deviation and right ventricular hypertrophy. Doppler echocardiography can generally make a clear diagnosis of the pathological anatomy of complete pulmonary venous connection. If Doppler echocardiography is unclear or accompanied by other cardiac malformations, MRI or cardiac catheterization is recommended. The latter two showed the reflux of the pulmonary vein by injecting a certain amount of contrast agent. Cardiac catheterization can also measure pulmonary artery pressure and oxygen saturation in the atria, but it is traumatic.
Different from the atrial septal defect and other congenital points, mainly relying on auxiliary examination to confirm the diagnosis.
