Pulmonary atresia with intact ventricular septum in children
Introduction
Introduction to pediatric septal intact pulmonary atresia Ventricular septal integrity of the pulmonary atresia refers to complete obstruction of the right ventricular outflow tract, but the ventricular septum is intact. According to the connection between the right ventricle and the pulmonary artery, there are two types: the first type, the right ventricular outflow tract, the pulmonary valve tissue malformation is a cavity without a cavity; the second type, the right ventricular outflow tract funnel cavity disappears with muscular atresia. The above classification has important clinical implications, and it has recently been reported that laser and radiofrequency ablation techniques are used to perforate the atresia valve. It has a good effect on the first type, but still lacks the ideal treatment for muscular atresia. basic knowledge Sickness ratio: 0.0012% Susceptible people: children Mode of infection: non-infectious Complications: congestive heart failure
Cause
Pediatric septal integrity of pulmonary artery atresia
(1) Causes of the disease
Most of these congenital malformations involve pulmonary atresia alone, which should be distinguished from pulmonary atresia with conical arterial malformation, and complex malformations with right aortic and transposition of the aorta (eg, pulmonary atresia with ventricular septal defect, with or without aorta Different transpositions, the unequal division of the conical trunk is the root cause of dysplasia of this type of malformed pulmonary artery, and the normal connection between the semilunar valve and the open right ventricular funnel suggests that pulmonary atresia is a primary independent Pathological changes, because the embryonic trunk dry ridges are initially separated from each other, and the three leaflets fuse into a non-porous membranous structure, indicating that this is a secondary change in the later stages of development, despite the right ventricular outflow tract, many suffering The three parts of the right ventricle still exist, and the right ventricular cavity is mild to moderately dysplastic. This supports the theory that the pathological changes in the right ventricle are secondary to the severity of tricuspid regurgitation, and the tricuspid regurgitation affects the right ventricle. In the case of filling, the obvious tricuspid regurgitation increases the right ventricular volume, resulting in a certain size of the right ventricular cavity, and the tricuspid valve function is still available. When the right ventricular outflow tract obstruction, the beams lead to different degrees of wall hypertrophy, right ventricular trabeculae even portion and the funnel portion closed.
The intramyocardial sinus gap described in the literature is a narrow and roundabout gap between the thicker septal bundles. Angiography clearly shows that these voids are consistent with typical sites of the right ventricular trabeculae, and tricuspid and pulmonary annulus development The defect is likely to be the result of obvious dysplasia of the ventricular cavity. In the process of cardiac tube formation, some cystic structures called mesangial sacs are formed on the dorsal side of the cardiac tube. Finally, this structure is located in the two layers of pericardium. In the fold, some of the mesangial sacs are arranged in a longitudinal tunnel, and the tunnel is opened in the cardiac lumen along the dorsal side of the cardiac tube. These mesangial sacs form a single layer of blood vessel wall, and finally develop into a coronary artery system with a cylindrical opening. Connected to the arterial trunk, so the connection between the coronary system and the right ventricular sinus is the connection between the embryonic mesangial sac and the right ventricular trabecular. This embryonic connection can be explained in some patients. Traffic between the coronary artery and the right ventricle.
(two) pathogenesis
Pathological anatomy
(1) Right ventricle: Although the main pathological changes are located in the pulmonary valve, due to obstruction of the right ventricular outflow tract, resulting in obvious pathological changes in the right ventricular inflow tract and body, Goor and Lillehei pioneered the division of the right ventricle into three parts. The described method, Bull et al. used this approach in the morphological classification of right ventricular malformations with pulmonary atresia, the right ventricular inflow tract refers to the area covered by the tricuspid valve, extending from the tricuspid annulus to the mitral valve The leaflet attachment area, beyond the attachment point of the tricuspid valve, the part extending to the apex of the right ventricle is the right ventricular trabecular portion, and the funnel is actually the right ventricular outflow tract connecting the right ventricular cavity and the blocked pulmonary valve portion, although the pulmonary artery is atresia Usually right ventricular dysplasia, the size of the right ventricular cavity is different, due to muscle hypertrophy outflow obstruction, part or more of the right ventricle may be closed, the most serious is the right ventricular cavity is very small, or even only the inflow section.
Closure of the trabecular bone leads to dysplasia of the right ventricle, small lumen, closed funnel, resulting in muscular atresia between the right ventricular cavity and the total dry cavity of the pulmonary artery. This segment is continuously interrupted, usually the endocardial thickening is white, similar to elastic fiber. Proliferation, sometimes the size of the right ventricle is close to normal, but rarely dilates. Usually, the size of the right ventricle can reflect the obvious abnormality of the inflow or outflow valvular structure. There are three parts of the right ventricle suggesting the tricuspid annulus and the funnel. The size of the right ventricle is often accompanied by obvious tricuspid regurgitation, which is present when the tricuspid valvular deformity is combined. Therefore, the size of the right ventricular cavity can be observed by observing the dysplastic three-part structure of the right ventricle. Qualitative estimates, in fact, the shape of the right ventricle and tricuspid valve, tricuspid annulus, right ventricular funnel, total trunk and branch size of the pulmonary artery significantly affect the treatment and prognosis of pulmonary atresia with ventricular septal integrity, therefore, right ventricle Measurement of the size of each part, especially the measurement of the size of the tricuspid annulus, is an integral part of the study of the pathological anatomy of this deformity, which is often accompanied by The right ventricular cavity and the myocardial sinus of the coronary arteries can lead to the expansion of the affected coronary artery. The dilated coronary artery can be seen in the external examination of the heart. The connection between the myocardial sinus and the coronary artery is common in the case of tricuspid occlusion. This connection can result in a right-to-left shunt, in which hypoxic blood is retrograde into the ascending aorta, and Freedom and Harrington further explain that blood may participate in the right circulatory shunt from the myocardial sinus, through the coronary arteries into the coronary sinus.
(2) Tricuspid valve: Tricuspid valve abnormalities are common and have different manifestations. The tricuspid valve controls the inflow of blood into the right ventricular cavity. Therefore, the abnormality of the tricuspid valve usually reflects the pathological changes associated with the right ventricle. When the valve is mildly dysplasia, the valve leaf is slightly thickened, and the leaflet and leaf junction are slightly fused. It is common in the right ventricle where all three parts exist. The right ventricular cavity is close to normal or mild dysplasia, and the valve is thickened and nodular. With the junction fusion, it often causes restrictive changes in the valve device, restricting the filling of the ventricular cavity, leading to the closure of part or parts of the right ventricular cavity. The most serious case is that the small tricuspid annulus and the small right ventricular cavity coexist, and the other In contrast, the anterior lobe is stalk-like, with the septal and posterior lobes moving down, similar to the typical Ebstein malformation, often with larger annulus, with severe tricuspid regurgitation and right ventricular lumen enlargement.
(3) funnel and pulmonary valve: most of the pulmonary atresia with open ventricular septum is open, the right ventricular cavity is connected with the pulmonary valve that tends to be locked, and the pulmonary valve leaflets fuse to form a septum, which can be seen on two, in most cases It is a trace of three valve fusions. In the narrow right ventricular cavity, the closure of the funnel leads to muscular atresia. The total trunk of the pulmonary artery is emitted from the right ventricle with a blind end, and gradually widens during extension. The pulmonary valve annulus and total trunk Both are dysplastic, in which case the pulmonary valve is usually not formed and is replaced by a pulmonary sinus that radiates from the bottom of the heart.
4. Pulmonary artery Despite pulmonary atresia, the majority of the pulmonary artery trunk and branch diameter are normal. The pulmonary circulation is supplied by a long and twisted arterial catheter. Pulmonary artery dysplasia is rare.
2. Pathophysiology usually increases right atrial pressure, "a" wave is obvious, on the contrary, because pulmonary venous return reduces left atrial pressure significantly, "a" wave is the same as "v" wave, right ventricular systolic pressure is significantly higher than systemic systolic blood pressure Even in the neonatal period as high as 100-150mmHg, the right ventricular pressure curve is triangular, similar to the waveform of the typical right ventricular outflow tract obstruction, usually the right ventricular end-diastolic pressure is increased, there is severe tricuspid regurgitation or Ebstein malformation When the right ventricular pressure can be mildly or moderately elevated, the pressure in the left ventricle is normal, and only the aorta can reach the pulmonary artery through the arterial catheter, but this operation can cause the arterial catheter to close. If the pressure of the pulmonary artery is measured, it should be Below the aortic pressure.
As the pulmonary circulation reduces blood flow and tissue oxygen uptake rate increases, systemic venous oxygen saturation is often reduced, down to 30% in the case of decreased cardiac output, and oxygen saturation and body veins in right atrium and right ventricle. The blood oxygen saturation of the reflux blood is similar. The degree of hypoxemia depends on the blood flow of the lung. The blood of the pulmonary venous return should be completely saturated. The atrial level must be shunted, and the oxygen saturation of the left atrium blood is very low. Due to the shunting blood flow through the patent foramen ovale, the blood oxygen saturation of the left atrium blood is often lower than the blood oxygen saturation of the left ventricular blood. If the arterial catheter remains open, the oxygen saturation of the systemic arterial blood flow can be maintained. More than 70% can guarantee the oxygen supply of the tissue and maintain the arterial pH. If the arterial catheter is closed, severe hypoxemia can occur and metabolic acidosis can occur.
Prevention
Pediatric septal integrity pulmonary artery atresia prevention
Ask family history to understand the genetic situation, investigate the impact of environmental factors to explore the cause of congenital heart disease, Shaw through the investigation of the address to understand the environmental teratogenic factors that the pregnant mother may be exposed, the address of the mother's production is sometimes used to represent The address of the early pregnancy was estimated by environmental factors. The authors investigated the address of the mother at the time of pregnancy and birth. About 24.8% of the mothers moved between the beginning of pregnancy and production, so observing the production address may reduce congenital malformation and the mother's exposure to the environment. The positive result of the association should be investigated in the environment of the address at the time of pregnancy. Schwanitz advocated that the detection of cardiac malformation before birth can be used as an indication for chromosomal examination. The authors mentioned that 588 fetuses were diagnosed with growth retardation and/or congenital malformation before birth. A chromosome examination was performed, and 116 (19.7%) of these cases were confirmed to have chromosomal abnormalities. Of these malformed fetuses diagnosed before birth, 102 (17.3%) had fetal malformations.
Therefore, cardiac malformation is the most common malformation. Of the fetuses diagnosed with cardiac malformations before birth, 41 fetuses (40.2%) have chromosomal abnormalities (the most common of 18 and 21 trisomy), except for In addition to monitoring the fetus, the mother's disease should also be monitored. Breton reported that the mother had phenylketonuria, and the plasma of phenylalanine increased continuously during pregnancy. The child born had a cardiac malformation. Breton reported a child. Coronary artery abnormalities originate from the right pulmonary artery, ventricular septal defect, fetal growth retardation and facial deformity. The parental plasma of phenylalanine is continuously increased during pregnancy. The cardiac malformation is diagnosed 8 months after birth, and its developmental delay is due to The mother is caused by phenylketonuria, which can also cause ventricular septal defect and coronary artery malformation. The authors suggest that if the mother begins a dietary treatment before pregnancy, it may prevent fetal damage, so if there is a deep understanding of the cause , before pregnancy, pregnant mothers and fetuses can be monitored for maternal disease and fetal malformations, if possible, should do their best Fetal congenital malformations occur, but from the perspective of genetics and environmental damage, the cause of congenital heart disease is not fully understood, and most of them are powerless in prevention, so explain the cause and fundamentally prevent congenital heart disease. The occurrence is still an extremely difficult task, and it is still necessary for scholars in clinical and basic fields to work together to explore.
Complication
Pediatric septal integrity pulmonary plexus atresia Complications, congestive heart failure
Often complicated by congestive heart failure and low cardiac output syndrome.
Symptom
Pediatric septal integrity pulmonary atresia symptoms common symptoms cyanosis metabolic acidosis elevating pulsatile arteriosus systolic murmur apnea respiratory dyspnea pulmonary artery atresia lung texture reduce hepatomegaly
Central hair loss occurs within a few hours after birth. As the arterial catheter is functionally closed, the cyanosis gradually worsens. The highly dilated right ventricle oppresses the lungs to cause different degrees of dysplasia, resulting in difficulty in breathing, shortness of breath, and physical examination showing apex to the left. Lateral displacement, apex beats are lifted, the first and second heart sounds are single sound, due to tricuspid regurgitation, the left lower edge of the sternum can be heard and the full systolic murmur, the upper left sternal border and the shortness of the patent ductus arteriosus Soft systolic jet murmur, intravenous infusion of prostaglandin E2, E1, catheter murmur enhanced, very few patients due to narrow heart chamber channel and low cardiac output, accompanied by pulse weakening, liver enlargement, according to Baby cyanosis develops rapidly, with metabolic acidosis, difficulty breathing, audible systolic murmurs in the lower left sternal border, low arterial oxygen saturation, reduced chest texture in the chest radiograph, and right ventricular and left ventricular angiography to determine the diagnosis.
Examine
Examination of complete pulmonary atresia in pediatric septum
When the infection is concurrent, the peripheral blood white blood cell count is increased.
1. Chest X-ray: The heart shadow is enlarged, and the severe tricuspid regurgitation is enlarged obviously. The heart shadow occupies most of the chest cavity, the lung field is clear, and the pulmonary vascular texture is reduced.
2. Electrocardiogram: characteristic performance is left axis of the electric axis, left ventricle predominance, right ventricular low voltage, right atrium enlargement, due to tricuspid atresia and left ventricle double entrance, ST-T segment changes often suggest Different degrees of subendocardial ischemia.
3. Echocardiography: the lower section of the xiphoid, two-dimensional ultrasound and pulsed Doppler can fully display the abnormal traffic in the double heart room, the parasternal and apical four-chamber view can show the size of the tricuspid valve, morphological changes and severity of reflux, The coronal, sagittal section of the sword can be divided into three parts according to the degree of right ventricular dysplasia. Because of the technical and anatomical structure of the right ventricle of the disease, the measurement of right ventricular volume is of little clinical significance. The method is to calculate the normal value of the diameter of the tricuspid annulus according to the body surface area, and then determine the right ventricle size by the Z index. The funnel cavity of the right ventricular outflow tract muscle atresia completely disappears, and the right ventricle and the main pulmonary artery trunk form a separation. The short-axis view of the parasternal aorta shows the best, the pulmonary valve atresia, the valve merges with each other, the funnel end forms a blind end, and the right ventricle contracts with a conical-like bulge, which is not easy to distinguish from pulmonary stenosis in two-dimensional ultrasound. Puller and color Doppler can see turbulence through the narrow pulmonary valve orifice, with or without reflux, the arterial catheter is often more vertical, on the sternum The cut surface is easier to see.
Two-dimensional ultrasound is not easy to judge whether there is right ventricular coronary traffic when right ventricular hypertrophy, color Doppler can detect sinusoidal blood flow, this sinus blood flow often occurs in the right ventricular cavity, high intraventricular pressure Cardiovascular angiography is an important basis for establishing a diagnosis.
4. Cardiac catheter: Cardiac catheter and cardiovascular angiography should be performed before surgery or transcatheter right ventricular decompression to determine the presence or absence of coronary stenosis or interruption. Hemodynamics shows that the right ventricular diastolic pressure is equal to or greater than the systemic pressure, low Less common in systemic pressure, common in tricuspid dysplasia, severe tricuspid regurgitation caused by Ebstein malformation and right ventricular stenosis, increased right ventricular end-systolic pressure, decreased compliance, due to the presence of non-restrictive heart Room traffic, the mean arterial pressure is similar, and the right lateral ventricle can show the tricuspid activity, size and right ventricular morphology, and whether there is right atrial coronary traffic. If there is no right ventricular coronary traffic, then no Right ventricular-dependent coronary circulation, and vice versa, does not indicate the presence of right ventricular-dependent coronary circulation, anterograde balloon closure or retrograde ascending aorta angiography can confirm the presence or absence of coronary stenosis or interruption, some patients need Coronary angiography can be used to determine the coronary artery.
5. CT and MRI: CT and MRI are rarely needed before surgery, but CT and MRI are quite common after surgery. MRI spin echo T1W image can better show postoperative pulmonary atresia with ventricular septal integrity. The size of the right ventricle and the thickness of the right ventricular myocardium can be compared and compared. The gradient echo film sequence shows abnormal blood flow through the narrow pulmonary artery and visible abnormal blood flow from the right ventricle into the right atrium. Contrast-enhanced magnetic resonance angiography and multi-slice spiral CT showed better peripheral pulmonary artery stenosis after surgery. For those who performed Blalock shunt surgery, it can be better to show whether the shunting pipeline is still smooth.
6. Cardiovascular angiography: Pulmonary atresia with ventricular septal complete angiography can be used for right ventricular angiography with NIH right heart catheter. For patients with very small right ventricle, right ventricle can be used for right ventricle angiography, but the injection speed should be reduced. Omi Parker 350, 1.0ml/kg, orthotopic and left-hand projection, left ventricular angiography or ascending aorta angiography for hepatic angiography, left heart catheter with pig tail, Omi Parker 350 contrast agent, 1.5 ml/kg for observation of coronary arteries, arterial catheters, collateral circulation vessels and pulmonary arteries.
In the neonatal period, there is an indication for cardiac catheterization to confirm the diagnosis, and interventional cardiac catheterization is also available. Percutaneous femoral vein puncture is feasible in most infants weighing more than 2 kg, sometimes with cardiac catheterization. Insertion of the dysplastic right ventricle through the tricuspid valve is very difficult. Cardioangiography should be performed according to the guidance of the echocardiographic findings. If the ultrasound examination confirms the presence of the funnel, once the cardiac catheter is inserted into the right ventricular cavity, the cardiac catheter should be manipulated to deliver it to The funnel, anterior and posterior anterior and posterior ventricles can show the right ventricle, and the inflow into the area covered by the tricuspid valve. The blood flow into the right ventricular cavity, which presents a negative shadow, showing the tricuspid annulus. The area beyond the tricuspid valve is the trabecular portion, and the contrast agent is further shown as the sac that terminates at the blind end of the outflow tract funnel.
At the same time, retrograde intubation through the femoral artery, manipulation of the cardiac catheter through the arterial catheter inserted into the pulmonary angiography, can clearly show the membranous structure of the atresia and the actual distance between the total dry cavity of the pulmonary artery and the funnel cavity, when the muscle type is locked, the right ventricular cavity and There is a long interval between the total trunk of the pulmonary artery.
In children with functional pulmonary atresia, a large amount of contrast agent is injected into the right ventricular trabeculum and then flows back into the right atrium, masking the forward blood flow of the total trunk of the pulmonary artery. This is why the catheter should be delivered to the funnel as carefully as possible. The reason for this is that only by delivering a catheter close to the pulmonary valve, a tiny jet through the extremely narrow valve can be found.
Echocardiography showed better tricuspid valvular deformity, although cardiovascular angiography showed a downward shift of the tricuspid valve with a sail-like change, with a negative shadow blocking the right ventricular outflow tract, usually with a large amount of contrast agent through the tricuspid valve. Counter-inflow into the extremely dilated right atrium may affect the discrimination of the right ventricular outflow tract.
Theoretically, right ventricular angiography can show the relationship between the sinus and the coronary artery, because the right ventricular pressure can force the contrast agent into the sinus fistula, so that the ascending aorta can be developed in advance, often the contrast agent flows back into the right atrium and the image overlap makes it difficult to find. Coronary stenosis, selective coronary angiography can overcome these difficulties, can show the proximal expansion of the coronary artery, contrast agent along the sinus into the right ventricular cavity, if there is coronary stenosis may also be found.
Transcatheter arterial angiography of the four-chamber and lateral can be used to show the pulmonary artery and its branches. The pulmonary artery branches are rare. In elderly patients who have undergone shunt surgery, angiography should be performed cautiously at the shunt site to show the presence or absence of pulmonary artery. Distortion and differences in left and right pulmonary artery size.
Diagnosis
Diagnosis and diagnosis of complete pulmonary atresia in pediatric septal
Need to be differentiated from the following congenital heart diseases:
1. Simple pulmonary stenosis: The pulmonary valve area of this patient can reach systolic tremor, and can smell loud and rough jet systolic murmur, which is most obvious in the second intercostal space on the left sternal border, and the second heart sound is weakened or Disappeared, chest radiograph showed clear lung field, prominent pulmonary artery shadow, right heart catheterization, right ventricular pressure increased significantly, pressure gradient between 1.3 kPa (10mmHg) between pulmonary artery and right ventricle, echocardiography and right ventricle The angiography showed that the main pulmonary artery had a stenosis and expanded.
2. Tricuspid valve down: It is very easy to be confused with pulmonary atresia with complete ventricular septum. Right ventricular angiography is extremely important. It can show that the displaced canopy-like anterior leaflet is in the right ventricular cavity, in the heart. The proximal edge of the lower edge presents all traces representing the position of the true annulus; it can also be seen that there is a second notch on the left side of the true tricuspid annulus, which indicates the attachment of the tricuspid valve that moves downward.
3. Pulmonary artery stenosis with atrial septal defect (Fala triplet): Patients with cyanosis are generally delayed compared with pulmonary atresia with complete ventricular septum, chest radiograph shows pulmonary artery segmentation, aortic node is small, right ventricular angiography shows pulmonary stenosis The right heart catheter measures the systolic pressure gradient between the right ventricle and the pulmonary artery at 1.3 kPa (10 mmHg) or more, and the left or right or left-to-left shunt exists at the house level. In addition, the atrial septal defect, Eisenmenger syndrome, Fallow IV Joint disease, etc., can be easily identified based on medical history, signs, echocardiography, right heart catheterization and angiography.
