Pulmonary artery atresia with intact ventricular septum (PA/IVS) is one of the rare forms of cyanotic congenital heart disease, accounting for approximately 1% of congenital heart malformations. More than 50% of untreated cases die in the neonatal period and 85% die within 6 months of age. Lesions include septal atresia with fusion of the pulmonary valve junction, varying degrees of stenosis of the annulus, and mild or moderate narrowing of the common pulmonary artery trunk. The tricuspid valve and right ventricle are hypoplastic, the ventricular septum is intact with secondary foramen ovale septal defect or patent foramen ovale, and an arteriovenous ductus arteriosus is necessary for survival of the child. Cardiac macrovascular connections are normal. Pathologic anatomy The main pathologic features are the absence of direct right ventricle-pulmonary artery continuity and intact ventricular septum, both combined with secondary foramen ovale septal defect or patent foramen ovale. Pulmonary atresia usually occurs in the valve or valve and funnel. In the former case, the pulmonary valve is septal-like atresia with complete fusion of the triple leaflet junction, and the pulmonary valve annulus and pulmonary trunk can be near normal in diameter; in the latter case, the pulmonary valve base is muscular with only shallow concave changes, and the funnel is atretic or severely dysplastic with a poorly developed pulmonary valve annulus and pulmonary trunk. In 45% of children, a right ventricular-coronary fistula is present, especially in children with severe right ventricular hypoplasia and small tricuspid valve openings, with a unique anatomic pattern of dependence on the right ventricular coronary circulation. Less than 10% of children have a combined inferior tricuspid valve malformation (Ebstein’s malformation), in which the right ventricle may be normal in size or even enlarged. Aortopulmonary collateral circulation is rare. There is no uniform clinical classification at home and abroad, and PA-IVS is classified according to the development of the right ventricle and tricuspid valve for surgical options: Bull and de Leval et al. classified PA-IVS into three types according to the different development of the three parts of the right ventricle: the right ventricular input, trabecularization, and funnel. Type I is where all three parts of the right ventricle are present, but with some degree of dysplasia; type II is where only the input and funnel parts are present and the trabecular part is occluded; and type III is where only the input part is present and neither the funnel nor the trabecular part is developed. Billingsley and colleagues classified PA/IVS as mild, moderate, or severe by combining the classification of Bull and Hanley et al. Hanley and Agnoletti et al. concluded that the diameter of the tricuspid valve and the size of the right ventricular cavity were positively correlated and that the diameter of the tricuspid annulus (Z value) was the determining factor for right ventricular development and the choice of procedure. The correction of the tricuspid orifice diameter (Z value) measured by right ventriculography or 2-dimensional echocardiography can be used to evaluate the surgical indications and guide the clinical procedure. Mild dysplasia: The right ventricle is well developed, with a well-developed input and funneled, trabeculated portion and a well-developed outflow tract. The size of the right ventricular cavity is approximately 2/3 or more of that of the normal control. The tricuspid valve Z value was between 0–2. Moderate dysplasia type: The right ventricular cavity and tricuspid valve size were approximately 1/3 to 2/3 of normal controls. three parts of the right ventricle were present, all of which were dysplastic. The degree of right ventricular outflow tract development allows for pulmonary valvuloplasty. Tricuspid valve Z-value between -2 and -4; severe dysplasia type: right ventricular cavity and tricuspid valve size less than 1/3 of normal control. right ventricular inflow tract only present or three parts unrecognizable, outflow tract absent or degree of development does not allow pulmonary valvuloplasty. The tricuspid valve Z value is between -4 and -6. It is often combined with a right ventricular coronary fistula or even a coronary circulation dependent on the right ventricle. Pathophysiology Cyanosis is present in the neonatal period due to right ventricular hypertension and right-to-left shunting at the atrial level. The open arterial duct is the only source of pulmonary blood, and the child’s pulmonary blood flow and oxygen saturation after birth are completely dependent on the shunt from the arterial duct. If the arterial duct is constricted or functionally closed after birth, this will result in pulmonary blood deficiency, progressively increasing hypoxemia and metabolic acidosis, and even death. In right ventricular hypertension, blood entering the right ventricle flows back into the right atrium via the tricuspid valve or retrogradely into the coronary circulation through the myocardial sinusoidal gap, leading to severe consequences of coronary underperfusion and myocardial ischemia once right ventricular decompression is performed. Blood returning from the body vein enters the left ventricle and aorta through the foramen ovale or atrial septal defect to mix with pulmonary venous blood. However, the diameter of the foramen ovale or atrial septal defect may limit the amount of right-to-left shunt, and if it is small, it may lead to right atrial hypertension and result in body vein stasis and low cardiac output in the body circulation. Incidence PA/IVS is one of the rare cyanotic congenital heart diseases, accounting for about 1% to 3% of congenital heart malformations as reported by different cardiac centers abroad. More than 50% of untreated cases die in the neonatal period and 85% die within 6 months of age. The embryologic mechanism of ventricular septal atresia is unknown, but it has been hypothesized that it is caused by a significant reduction in blood flow through the tricuspid valve and the right ventricle. In contrast, the mechanism of right ventricle-coronary artery fistulae is due to direct return of normal coronary venous return from the right ventricle into the right ventricle itself via the minimal cardiac vein (Thebesian), rather than into the coronary sinus. The right ventricle is hypertensive due to pulmonary atresia, and the return blood flows back into the coronary artery via the Thebesian vein. Clinical manifestations Symptoms: most children present with cyanosis of the cheeks, lips, and fingertips a few days after birth, pauses in breastfeeding, excessive sweating, short periods of shortness of breath, increased cyanosis, dyspnea, progressive hypoxemia, and moderate metabolic acidity. The degree of cyanosis depends on the amount of blood flow from the ductus arteriosus to the pulmonary artery, if accompanied by a large ductus arteriosus the degree of cyanosis, metabolic acidosis can be mild. Signs: cyanotic face, inspiratory trismus, poor peripheral perfusion of the extremities. Most of the tricuspid regurgitant all-systolic murmur can be heard at the left edge of the sternum, or systolic-based continuous murmur of the arterial duct can be heard, and the first and second heart sounds are single, and the heart murmurs are more variable. Imaging 1. Chest X-ray: The child’s heart is not large or mildly enlarged at birth, with depressed or flat pulmonary segments and varying degrees of reduced pulmonary blood. When tricuspid valve closure is incomplete, the right atrium is enlarged, and if the tricuspid valve is severely regurgitated, the heart enlarges significantly. 2.64-row spiral CT cardiovascular reconstruction: It has unparalleled diagnostic value and can visualize right ventricular outflow tract atresia, right ventricular dysplasia, unclosed arterial duct alignment, size, right ventricular size, whether combined with right ventricular coronary artery fistula and other intracardiac and macrovascular malformations. Cardiac catheterization: Prior to surgery or transcatheter right ventricular decompression, cardiac catheterization and cardiovascular angiography should be performed to determine the presence of coronary artery stenosis or interruption. Hemodynamics shows that the diastolic pressure of the right ventricle is equal to or greater than the pressure of the body circulation. It is rare to find a pressure lower than that of the body circulation, but it is common to find severe tricuspid regurgitation due to tricuspid dysplasia, Ebstein’s malformation, and right ventricular stenosis. Right ventricular end-systolic pressures are elevated and compliance is reduced. The right and left mean arterial pressures are similar due to the presence of nonrestrictive interventricular traffic. Ortho-lateral right ventriculography films show tricuspid valve activity function, size, and right ventricular morphology, as well as the presence of right atrial coronary artery traffic. If no right ventricular coronary artery traffic is present, there is no right ventricle-dependent coronary circulation, and conversely, it does not indicate the presence of a right ventricle-dependent coronary circulation. The presence or absence of coronary stenosis or interruption can be confirmed by a cisplane balloon closure or by retrograde ascending aortography. In some patients, coronary angiography is required to clarify the coronary artery course. 4.Echocardiography: A necessary diagnostic test. 2D Doppler echocardiography can show right ventricular outflow tract absence or narrowing, which is a characteristic manifestation. It can also show pulmonary atresia, dysplasia of right ventricle and tricuspid valve, hypertrophy of right ventricular wall and small right heart cavity, regurgitation of tricuspid valve, the size of atrial septal defect and the degree of development of pulmonary artery trunk and its branches, and the measurement of arterial duct can make judgment on the degree of hypoxia and prognosis. Diagnosis The diagnosis can be made based on history and signs, combined with echocardiography, electrocardiography and X-ray chest radiographs. Cardiac catheterization is the only reliable means of assessing coronary anatomy and determining the presence of a right ventricular myocardial sinusoidal gap traffic coronary malformation. Selective cardiovascular angiography must include a right ventriculogram, which clearly demonstrates right ventricular cavity size, tricuspid regurgitation, and the blind end of the right ventricular funnel. Retrograde aortic cannulation at the site of arterial catheterization can satisfactorily demonstrate the blind end of the pulmonary trunk and the condition of the left and right pulmonary arteries, allowing measurement of the distance separating the funnel from the blind end of the pulmonary artery. Treatment PA-IVS has an aggressive onset and a high natural mortality rate. Children with PA-IVS depend on the PDA for survival after birth, and once the PDA is closed, the child quickly dies, so treatment should be provided as soon as possible. There is no universally agreed treatment strategy that is suitable for all cases. The development of ventricular septal intact pulmonary atresia is rare and experience with individualized treatment is relatively limited. The ideal treatment plan depends on the morphologic and physiologic basis of the individual case.