Tetralogy of Fallot in children
Introduction
Introduction to children's tetralogy of Fallot Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. There are four main pathological changes: aortic root widening, right shifting, stenosis, ventricular septal defect, and ventricular septal defect. ) with right ventricular hypertrophy. The first three items are primary lesions, which are of great significance; while the right ventricular hypertrophy is a secondary change, which is the result of the above-mentioned deformity. Echocardiography has a very specific manifestation of this disease and can be used as a basis for the diagnosis of this disease. basic knowledge The proportion of illness: 0.001% Susceptible population: newborn Mode of infection: non-infectious Complications: cerebral thrombosis, brain abscess, infective endocarditis, disturbance of consciousness, headache, hemoptysis
Cause
The cause of tetralogy of Fallot in children
Congenital factors (35%):
The key period of cardiac embryo development is that in the second to eighth weeks of pregnancy, congenital cardiovascular malformation also occurs mainly at this stage. There are many reasons for the occurrence of congenital heart disease, which are roughly divided into two types: internal and external. Among them, the latter are more common, and the internal factors are mainly related to heredity, especially chromosomal translocations and aberrations, such as 21-trisomy syndrome, 13-trisomy syndrome, 14-trisomy syndrome, 15-trisomy syndrome. And 18-trisomy syndrome, etc., often associated with congenital cardiovascular malformations.
Infection factor (45%):
In addition, the incidence of cardiovascular malformations in children with congenital heart disease is significantly higher than the expected incidence. Among the external factors, intrauterine infections, especially viral infections such as rubella, mumps, influenza and ke, are more important. Saatchi virus, etc.; other exposure to large doses of radiation during pregnancy.
Other factors (10%):
The use of certain drugs, metabolic diseases or chronic diseases, hypoxia, maternal age (near menopause), etc., are at risk of congenital heart disease.
Pathogenesis
Pathological anatomy
(1) ventricular septal defect and pulmonary stenosis: the main pathological anatomical change of tetralogy of Fallot, due to the shift of the conical septum to the left and left, can not be connected with the sinus compartment of the normal position, so under the aortic orifice Large ventricular septal defect can be divided into aortic anomaly and large right shift: riding over the interventricular septum can simultaneously receive blood flow from the left and right ventricles. The aortic ride is related to the position of the ventricular septal defect, but regardless of the main The degree of arterial right shift is significant, and the aortic valve and anterior mitral valve are still anatomically continuous.
2. Hemodynamic changes
Due to pulmonary stenosis, right ventricular discharge is blocked, pressure is increased, so right ventricular hypertrophy, due to stenosis, blood flow is difficult to enter the pulmonary artery, pulmonary circulation is significantly reduced, reflux to the left atrium is also less, so the latter volume is significantly smaller, in Extremely narrow and even pulmonary atresia, its hemodynamic changes are similar to type IV permanent arterial trunk, due to pulmonary stenosis, blood flow is not easy to pass, right ventricular pressure rises, close to or equal to left ventricular pressure, so the general interventricular septum Different from the defect, the left-to-right shunt does not predominate. During the systole, part of the blood in the right ventricle and the left ventricular blood are simultaneously injected into the widened aortic root, and then enter the systemic circulation. At this time, the blood in the aorta is mixed. In the right ventricular blood without oxygenation, the blood oxygen saturation is reduced, so there are cyanosis, and cases with severe cyanosis, most of them die shortly after birth, while those with narrower stenosis have smaller flow from right to left, and may simultaneously There is a left-to-right shunt, so patients can have no obvious cyanosis, clinically known as no cyanosis tetralogy or ventricular septal defect with mild pulmonary stenosis
Prevention
Pediatric tetralogy prevention
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.
Complication
Complications of tetralogy of Fallot in children Complications, cerebral thrombosis, brain abscess, infective endocarditis, disturbance of consciousness, headache, hemoptysis
Common complications are cerebral thrombosis, brain abscess and infective endocarditis. TOF has the following complications:
1. Cerebrovascular accident (cerebrovascular accident) occurs in children less than 2 years old, due to increased hematocrit, increased blood viscosity, easy to lead to cerebral thrombosis and cerebral embolism, especially due to some factors caused by dehydration When it is more likely to appear, when the brain is embolized, the child presents with sudden disturbance of consciousness or hemiplegia.
2. Brain abscess (brain abscess) occurs mostly in children over 2 years old. It may be an embolus in the venous blood that is infected by bacteria. The shunt site directly circulates to the aorta and enters the brain; or because of blood viscosity. Increased, causing cerebrovascular thrombosis, and then infection to form a brain abscess; or due to reduced cerebral blood flow, brain tissue hypoxia caused focal brain tissue softening and secondary infection, the child showed fever, headache, vomiting, Sleepiness, there may be positioning signs such as convulsions and hemiplegia.
3. Infectious endocarditis (infectious endocarditis) occurs in the total branch of the pulmonary artery, more common in children after cardiac surgery, the mortality rate is higher, when the child has unexplained fever, should consider Infective endocarditis.
4. Children with bleeding tendency TOF often have thrombocytopenia or abnormal blood coagulation mechanism, which causes bleeding. Due to the circulation of the medial branch of the lung, hemoptysis can also be caused.
Symptom
Symptoms of tetralogy of Fallot in children Symptoms Common symptoms of children crying disturbed dyspnea of the patent ductus arteriosus convulsions systolic murmurs lips and nail bed slightly blueish atrial septal defect dizziness
Cyan
Its main performance, the extent and appearance of the morning and evening and the degree of pulmonary stenosis, more common in superficial capillary-rich parts, such as the lips, nails (toe) nail bed, ball-bound membrane, etc., due to decreased blood oxygen content, activity endurance Poor, a little activity such as crying, emotional, physical labor, cold, etc., can appear anxious and cyanosis.
2.
There are many symptoms of sputum in the children. When walking, during the game, they often take the initiative to squat for a while, when the lower limbs flex, the blood volume of the veins is reduced, the heart load is reduced, and the lower extremity arteries are compressed, and the resistance of the body circulation is increased, so that the right direction The left sub-flow is reduced, so that the symptoms of hypoxia are temporarily relieved. The small babies who do not walk often like to pick up the adults and bend the lower limbs.
3. The clubbing (toe) The child is in an oxygen-deficient environment for a long time, which can cause the capillaries and toe capillaries to expand and proliferate, and the local soft tissue and bone tissue also proliferate and hypertrophy, which means that the finger (toe) end is swollen like a drumstick.
4. Paroxysmal hypoxia
More common in babies, the inducement of eating, crying, emotional, anemia, infection, etc., manifested as paroxysmal dyspnea, severe cases can cause sudden fainting, convulsions, and even death, the reason is due to the funnel On the basis of stenosis, sudden onset of muscle spasm, causing temporary pulmonary artery obstruction, resulting in increased cerebral hypoxia, older children often complain of headache, dizziness.
5. Physical examination
The growth and development of children are generally slower, and the intelligent development may be slightly behind normal children. The anterior region of the anterior cerebral region is slightly elevated, and the second, third, and fourth intercostals of the sternum can be heard with grade II to III coarse jet systolic murmurs. This is caused by pulmonary stenosis, generally no systolic tremor, the second sound of the pulmonary artery is weakened, and some children can hear the second heart sound of hyperthyroidism, which is transmitted from the right aorta, severely severe, or in the burst In the onset of dyspnea, no murmurs can be heard, and continuous murmurs of the collateral circulation can sometimes be heard. The cyanosis lasts for more than 6 months, and the clubbing (toe) appears.
Examine
Examination of children with tetralogy of Fallot
Blood examination, peripheral red blood cell count and hemoglobin concentration increased significantly, red blood cells can reach (5.0 ~ 8.0) × 1012 / L, hemoglobin 170 ~ 200g / L, hematocrit is also increased, 53 ~ 80 vol%, thrombocytopenia, thrombin The original time is extended.
1. X-ray examination: the size of the heart is generally normal or slightly increased. The typical anterior and posterior heart shadows are "boots", that is, the apex is round and blunt, the pulmonary artery is concave, the upper mediastinum is wider, and the hilar vasculature is reduced. The lateral lung texture is reduced, and the transillumination is increased. The older children may have a reticular texture in the lung field due to collateral circulation, and the right aortic arch shadow may be seen in 25% of the children.
2. Electrocardiogram: typical cases show right axis deviation, right ventricular hypertrophy, severe stenosis often appear myocardial strain, visible right atrial hypertrophy.
3. Echocardiography: Two-dimensional ultrasound left ventricular long-axis view can be seen that the aortic inner diameter is widened, the ride spans above the interventricular septum, the interventricular septum is interrupted, and the degree of aortic ride can be judged; the short axis view of the aorta can be seen. Right ventricular outflow tract and pulmonary stenosis. In addition, the right ventricle, the right atrium has an increased inner diameter, and the left ventricular diameter is reduced. Color Doppler blood flow imaging shows that the right ventricle directly injects blood into the aorta.
4. Cardiac catheterization: The right ventricular pressure is significantly increased, which is equal to the systemic pressure, and the pulmonary artery pressure is significantly reduced. The continuous curve of the cardiac catheter exiting from the pulmonary artery to the right ventricle shows a significant pressure gradient, which can be based on the shape of the continuous curve. To determine the type of stenosis, the cardiac catheter is easier to enter the aorta or left ventricle from the right ventricle, indicating the presence of right aorta and ventricular septal defect. The catheter is not easy to enter the pulmonary artery, indicating that the pulmonary artery stenosis is lower than that of the heavy femoral artery. Less than 89%, indicating the presence of a shunt in the right to left.
5. CT and MRI: CT and MRI examinations have certain help in the diagnosis of tetralogy of Fallot. CT and MRI can determine the size and location of ventricular septal defect by observing whether the continuity of interventricular septum is interrupted. The main value of CT and MRI examination is to show peripheral pulmonary artery, collateral vessels and coronary artery. The MRI spin echo T1W image can show good right ventricular enlargement and right ventricular hypertrophy. The spin echo T1W image can also be better. Display of ventricular septal defect and right ventricular funnel stenosis, can also be displayed for aortic riding, MRI gradient echo film sequence can accurately measure left ventricular end-diastolic volume and left ventricular ejection fraction, angiography enhanced magnetic resonance vascular Imaging sequence and multi-slice spiral CT showed good peripheral pulmonary stenosis in tetralogy of Fallot, and showed strict stenosis of pulmonary artery, stenosis of pulmonary artery bifurcation, stenosis of left and right pulmonary artery and peripheral pulmonary stenosis. Because contrast-enhanced magnetic resonance angiography and multi-slice spiral CT are retrospective MIP reconstructions on the workstation to show the pulmonary artery, you can freely choose any angle to display the lungs. Pulse, therefore, the stenosis of the left and right pulmonary artery is sometimes better than the cardiovascular angiography. Contrast-enhanced magnetic resonance angiography and multi-slice spiral CT can also display the collateral vessels of the tetralogy of Fallot. Although the spatial resolution of contrast-enhanced magnetic resonance angiography and multi-slice spiral CT images is not as good as that of DSA, the CT and MRI can be reconstructed transversely, which is used to distinguish the pre-positional pulmonary artery from the lateral branch of the posterior position. Circulating blood vessels are helpful, at this point, contrast-enhanced magnetic resonance angiography and multi-slice spiral CT are superior to DSA angiography, tetralogy of Fallot with coronary artery abnormalities, contrast-enhanced magnetic resonance angiography and multi-slice spiral CT also has its unique diagnostic value. Because of the ability to perform transverse reconstruction, CT and MRI are more intuitive and reliable for determining whether the abnormal coronary artery is crossing the right ventricular outflow tract than DSA angiography, but CT and MRI for coronary artery. The display rate is still lower than DSA cardiovascular angiography. Relatively speaking, multi-slice spiral CT has a higher rate of coronary artery display than MRI, and is closer to DSA cardiovascular angiography.
6. Cardiovascular angiography tetralogy of coronary angiography is best to do both right ventricular angiography and left ventricular angiography. The typical manifestation is that the contrast agent can be injected into the right ventricle and the aorta and pulmonary artery can be seen almost simultaneously. Can see the location of the ventricular septal defect, thickened aortic shadow, and the position is biased to the front, slightly to the right; to understand the location and extent of pulmonary stenosis and the morphology of the branches of the pulmonary artery, selective left ventricular and aortic angiography can further understand the left The development of the ventricle and the direction of the coronary arteries, in addition, the accompanying malformations can be found by angiography, which is essential for the development of surgical procedures and estimation of prognosis.
Right ventricular angiography placed the head of the NIH right angiography catheter at the apex of the right ventricle, and the projection was taken to sit in the position. The sitting position was mainly used to display the pulmonary artery. When the angle was 40° to the head, the X-ray was perpendicular to the pulmonary artery. The bifurcation and the origin of the left and right pulmonary artery were well displayed. The contrast agent, 1.2-1.5 ml/kg tetralogy of Fallot's angiography was also often used for long-axis oblique left ventricular angiography, and the catheter was selected for pig tail catheter. The head end was placed in the apex of the left ventricle, and the contrast agent was treated with Omega Parker 350, 1.5 ml/kg. For some cases, ascending aorta angiography was added, and catheter selection and contrast injection were the same as left ventricular angiography.
The right ventriculography of tetralogy of Fallot mainly observes the anatomy of the pulmonary artery and right ventricular outflow tract. The normal pulmonary artery is from the front to the back. When the orthotopic projection is repeated, the pulmonary artery overlaps. The pulmonary artery of the tetralogy of Fallot is more than the normal heart. At the level, the pulmonary artery overlap shortens more severely. Therefore, the right ventricular angiography of the tetralogy of Fallot must be performed with the sitting position to make the X-ray and the pulmonary artery tend to be perpendicular, reduce the overlap of the pulmonary artery, and the right ventriculography can be better. Pulmonary annulus stenosis, valve thickening, stenosis, pulmonary trunk stenosis, pulmonary bifurcation stenosis, stenosis of the left and right pulmonary artery and pulmonary stenosis in the lung, in order to better observe the beginning of one pulmonary artery, On the basis of sitting position, compound left oblique or right oblique 5 ° ~ 15 °, sitting position complex with mild left anterior oblique, can show the beginning of the left pulmonary artery well, but the right pulmonary artery start and right ventricular funnel display Poor, sitting in the complex position of the right right anterior oblique position, the right pulmonary artery and the right ventricular funnel showed good, while the left pulmonary artery showed poor appearance, sitting on the complex complex right front In the position, the reason for the good display of the funnel is that the aortic position of the tetralogy of Fallot is ahead of the head, and only the right right anterior oblique is needed. The aorta and the pulmonary trunk are in a lateral relationship, and the X-ray is tangent to the conical interval. The shifting of the funnel and the display of the hypertrophy are the best. When the right ventricular contrast is read, the right ventricular funnel should be observed first. The normal right ventricle of the right ventricle is trapped in a small and large trapezoid. In the case of tetralogy of Fallot, the right ventricular funnel has a small transverse diameter, which is tubular or ups and downs. The funnel is displaced to the right ventricle and is hypertrophic. The shape of the funnel is still abnormal during the diastolic phase of the ventricle. This stenosis is an organic change. Secondly, the pulmonary valve should be observed. Normally, the diameter of the pulmonary valve annulus is not less than the aortic annulus. The pulmonary valve leaflets are thin like paper. When the ventricle contracts, the valve leaflets are open. The tetralogy of Fallot The pulmonary valve annulus is significantly smaller than the aortic annulus, the pulmonary valve is obviously thickened, and the valve leaf opening is limited. In addition, the pulmonary artery trunk and the left and right pulmonary artery should be observed. The normal cardiac pulmonary trunk is similar to the diameter of the ascending aorta. At room angiography, the ascending aorta and the pulmonary trunk are simultaneously developed, and the pulmonary trunk is significantly narrower than the ascending aorta. In the past, the ratio of the ascending aorta to the diameter of the pulmonary trunk was measured to determine the severity of the tetralogy of Fallot. It has been used sparingly, and the right ventricular angiography of the pulmonary artery is tubular, funnelform or localized stenosis can be well displayed, and the stenosis of the pulmonary trunk bifurcation is also very good. The observation of peripheral pulmonary stenosis is tetralogy of Fallot. One of the main purposes of right ventricular angiography, the anatomy of the funnel and the pulmonary valve are in the direct view of the surgery, and the intraoperative stenosis is clearly seen, but if the stenosis of the surrounding pulmonary artery is not diagnosed before surgery, it is difficult to be It was found that peripheral pulmonary stenosis is the most common localized stenosis at the beginning of the left pulmonary artery. Others such as the stenosis of the right pulmonary artery, uniform stenosis of one pulmonary artery and localized stenosis of the pulmonary artery should also be observed. The ventricular cavity is large, and the trabecular muscle is rough. When angiography, attention should be paid to the presence or absence of filling defects in the right ventricle to avoid missed right ventricular double lumen.
Sitting right ventricular angiography has a certain value in determining the type of ventricular septal defect. Right ventricular angiography shows that the contrast agent enters the ascending aorta through the ventricular septal defect. Usually the upper edge of the ventricular septal defect and the pulmonary valve are ascending and the lower edge is The tricuspid annulus is adjacent, if there is a distinct muscle bundle between the lower edge and the tricuspid valve to separate it, suggesting a ventricular septal defect in the funnel, if the upper edge of the ventricular septal defect is close to the pulmonary valve, and the contrast agent enters the aorta Later, along the left wall of the ascending aorta, suggesting a subvalvular ventricular septal defect, but right ventricular angiography can not diagnose or rule out multiple ventricular septal defect.
The preferred position of left ventricular angiography for tetralogy of Fallot is long-axis oblique position. Because the heart of tetralogy of Fallot often rotates clockwise, when the long axis is oblique, the left oblique angle should be slightly larger, with a left oblique angle of 65°-75. ° is the best angle, when reading the film, we should first pay attention to the observation of ventricular septal defect. The long-axis oblique left ventriculography X-ray is tangent to the anterior chamber, which can directly show the main ventricular septal defect of tetralogy of Fallot. Signs, to understand the size and location, when observing the ventricular septal defect, to observe the presence or absence of multiple ventricular septal defect, long-axis oblique left ventricular angiography, such as under the main ventricular septal defect, see contrast agent from the left ventricle to the right Room shunt, indicating multiple ventricular septal defect in the muscle, left ventricular angiography or exclusion of multiple ventricular septal defect is significantly better than right ventricular angiography, long-axis oblique left ventricular angiography X-ray and ventricular septal tangential position, can The degree of aortic ride is well displayed. During ventricular diastolic, blood without contrast agent enters the left ventricle from the left atrium, forming a circular negative shadow, which outlines the mitral valve and shows the mitral valve. Continuous performance with aortic valve fibers, When the axial oblique position is projected, the aortic arch can be well opened, showing whether or not the arterial catheter is closed, and the long-axis oblique left ventricle angiography is developed, and the left and right ventricles are not overlapped, which can better judge the left ventricular development. Long-axis oblique projection can also better show the localized stenosis at the beginning of the left pulmonary artery.
In the long-axis oblique left ventriculography of tetralogy of Fallot, about 90% of the cases have good coronary arteries. In patients with normal coronary arteries, the left main coronary artery can be clearly seen behind the aortic valve. Two branches, the circumflex branch moves backwards in the left atrioventricular sulcus, and the anterior descending branch moves forward in the interventricular sulcus. If no anterior descending branch is seen from the left coronary artery, it is necessary to observe whether it originates from the right coronary artery. Proximal, single left coronary artery is another common coronary artery abnormality. After clearing a single coronary artery, attention should be paid to the location of the right coronary artery. If the right coronary artery is emitted from the left anterior descending artery, it must cross the right. The outflow tract of the chamber affects the operation. If the right coronary artery is emitted from the left circumflex artery, it will travel behind the aorta and will not affect the operation. If the right coronary artery is emitted from the trunk of the left coronary artery, the direction of travel may be uncertain and may be crossed forward. Right ventricular outflow tract, may also be behind the aorta, combined with other body position analysis, left ventricular angiography failed to show coronary anatomy or suspected coronary artery abnormalities, should be added as aortic root angiography, the main Pulse sufficient display contrast general coronary anatomy, without having to rely selective coronary angiography Coronary displayed.
The angiographic examination of tetralogy of Fallot with one-sided pulmonary atresia is complicated. If the blocked pulmonary artery is supplied by the arterial catheter, hemiplegia or axonal elevation or aortic arch angiography can be used to show the pulmonary artery. If the lung is blocked, The pulmonary artery is supplied by the systemic circulation-pulmonary collateral vessels, and the pulmonary artery can be displayed by sitting or orthotopic aortic angiography, or the Cobra and other elbow catheters can be used for selective collateral circulation angiography to show the pulmonary artery. If the pulmonary artery can be displayed, the pulmonary vein wedge imaging should be added. This method can often display the blocked pulmonary artery.
Diagnosis
Diagnosis and diagnosis of tetralogy of Fallot in children
diagnosis
Diagnosis can be made according to clinical manifestations and auxiliary examinations. The diagnosis of typical cases is not difficult. Cyanosis appears in several months after birth, with paroxysmal dyspnea and hypoxic episodes. After activity, magpies, rarely heart failure, in the left sternum The third and fourth intercostal and intermittent systolic murmurs with P2 attenuation, combined with laboratory tests and X-ray, electrocardiogram, echocardiography, can make a preliminary diagnosis, the diagnosis requires cardiac catheterization and cardiovascular angiography There is a special change in the ultrasonography of the tetralogy of Fallot, especially the diagnosis of aortic riding, continuous interruption of the anterior, pulmonary stenosis, right ventricular diversion, etc., but it is also difficult to pay attention to other abnormalities. There are common malformations with atrial septal defect or patent foramen ovale, right aortic arch, left superior vena cava, patent ductus arteriosus, coronary artery malformation and complete anomalous pulmonary venous drainage.
Differential diagnosis
TOF is still required to be diagnosed with the following congenital heart disease.
1. Complete transposition of great blood vessels: Cyanosis appears earlier and more obvious, often with severe cyanosis at birth, and congestive heart failure can occur 1 to 2 weeks after birth, X-ray shows The lungs are congested, the heart shadow is enlarged into an egg shape, and the electrocardiogram shows severe right ventricular hypertrophy or left and right ventricular hypertrophy.
2. Ventricular septal defect The mild or no-purple TOF is often confused with simple VSD. The identification points are referred to as "ventricular septal defect". When the larger ventricular septal defect is associated with pulmonary hypertension, the B-ultrasound examination has a continuous interruption. The ventricle level is divided from right to left, but the larger ventricular septal defect with pulmonary hypertension is significantly enlarged in the left ventricle, the aortic width is normal, the pulmonary artery is widened, and the aortic riding is not obvious.
3. Double outlet of right ventricle with pulmonary stenosis: clinical symptoms and TOF are very similar, but the disease is generally innocent, X-ray examination shows increased heart shadow, cardiovascular angiography can be diagnosed, The main difference between the right ventricle double outlet and the tetralogy of Fallot is that there is no anatomical connection between the aortic valve and the anterior mitral valve, which is the main identification point of the tetralogy of Fallot and the double outlet of the right ventricle.
4. Pulmonary stenosis: The clinical manifestations are similar to those with light or no bruising, but the position of the murmur is higher. The second intercostal space on the left sternal border smells rough systolic murmur. X-ray examination shows increased heart shadow and total pulmonary artery. After the stenosis and expansion, the electrocardiogram shows that the right ventricle is severely hypertrophied and has a high-point P wave.
5. Trilogy of Fallot: including atrial septal defect, pulmonary stenosis, right ventricular hypertrophy, late appearance of bruising, sometimes in a few years, sputum is not common, jet rupture of the second intercostal space on the left sternal border The duration of the murmur was longer, with obvious tremor, P2 division, X-ray examination showed that the right atrium was also enlarged, the right atrium was also enlarged, the pulmonary artery segment was convex, there was no right aortic arch, the lung blood was normal or decreased, and the electrocardiogram was high. P wave.
