| Tetralogy of Fallot (tetralogy of Fallot, TOF) is a common congenital heart malformation, with the highest prevalence in infants with cyanotic heart defects and 10% prevalence of all congenital heart disease, which is characterized by the pulmonic stenosis, ventricular septal defect, an overriding aorta and right ventricular hypertrophy. It was generally divided into two types:mild and severe, according to its clinical symptoms. In severe cases, Fallot patients are usually with the formation of aortopulmonary collateral vessels due to the lack of or no cardiac sources of pulmonary blood supply,. Although the early mortality rate of TOF after operation has been reduced to 2%-3%, among which 50% severe TOF with aortopulmonary collateral arteries (APCAs) accounted for 50%. So more and more attention must be paid to the research and treatment of APCAs.The APCAs are usually thought to be originating from the descending thoracic aorta or its collateral vessels, connecting with the peripheral pulmonary arteries, or providing pulmonary blood flow to the lung segment or lobe, yet without connected vessels with its central pulmonary artery. APCAs were formed in embryonic period mostly because of aortic arch dysplasia and partial due to inadequate compensatory pulmonary blood formation. In pulmonary stenosis especially severe stenosis or atresia patients, more APCS are required in pulmonary blood supply in order to meet the metabolic demands.However, the pressure of APCAs that are mainly fed by the systemic circulation is relatively high, which making the long-term effect on the pulmonary vascular bed which can easily result in distal pulmonary artery hypoplasia, in turn, may result in heart failure. Although part of the APCAs were found narrow or tortuous to some extent at the opening or in the lung which can provide protection for the pulmonary artery, avoiding the occurrence of pulmonary arterial hypertension,yet severe stenosis and tortuosity were taken a long time, which will cause pulmonary vascular dysplasia supplying blood to the segment.The pathological changes of pulmonary vascular were found diversity in patients with tetralogy of fallot associated with APCAs, obviously increased the difficulty of treatment of heart operation. Whether any operation mode is chosen, if the APCAs were not treated in advance, yet intracardiac malformation was repaired and right ventricular outflow tract was reconstructed directly, after the establishment of a large number of extracorporeal circulation, the blood from systemic circulation enter into into the pulmonary circulation reflux to left ventricular by APCAs, which may lead to lung injury and left ventricular congestive heart failure, thereby increasing the mortality of patients. So to speak, the origin, number, size, direction and branches of APCAs, and its pulmonary vascular pathological change often show diversity, whihch is directly influenced the selection and effect of operation. So it is extremely important to understand in detail before operation and handle properly in operation.Tetralogy of Fallot is one the most common cyanotic complex congenital heart disease, and its main pathophysiological change is ischemia, the degree of which is mainly depended on the mutual influence of the right ventricular outflow tract stenosis and ventricular septal defect. When it is serious, it not only can obviously influence the patient’s physical growth and development, but also can affect the intellectual development. Its mortality is remain high. However, the literature about the correlation between the APCAs and pathological and physiological parameters is still less. The data about the factors affecting the screening current is also very fragmentary, which is directly influenced the understanding and cognition of APCAs.The origin, number, size, direction and branches of APCAs and pulmonary vascular pathological are various, affecting the choice of operation mode and effect. Therefore, to investigate the distribution and morphological characteristics of APCAs and to explore the relationship between pathological and physiological parameters and the APCAs have clinical significances. Our purpose is by summarizing the distribution and the morphological characteristics and making a preliminary study on the relation between APCAs and the physiological and pathological parameters of TOF to strengthen the understanding of aorto-pulmonary collateral arteries and chose right method for surgery to improve operation effect, all of which is hoping to reduce the mental and economic burden of patient and their family and create a better social value.PARTIThe Distribution And Morphological Characteristics Of Patients With Aortopulmonary collaterals in tetralogy of FallotObjectiveTo summarized the distribution and the morphological characteristics of patients with aorta-pulmonary collateral arteries (APCAs) in tetralogy of Fallot (TOF).MethodsWe retrospectively analyzed the computed tomography angiography (CTA) images data of 67 TOF patients with APCAs from March 2010 to December 2014 Distribution, number and the morphological features of APCAs were recorded and summarized.Results1. Totally 178 APCAs were found (mean 2.66/case) in 67 cases. The APCAs were usually found at the ascending aorta and its main branches, the branches of aortic arch, the superior, middle and inferior part of thoracic aorta, the abdominal aorta and main branches. In this group, the APCAs was found mainly at the middle part of thoracic aorta (65 branches,36.52%), followed by the superior part of the thoracic aorta (48 branches,26.97%), inferior part of thoracic aorta (25 branches,14.05%), branches of aortic arch (18 branches,10.11%), aortic arch (15 branches,8.43%), abdominal aorta (5 branches,2.80%) and the ascending aorta (2 branches,1.12%).APCAs were divided into three types according to the origination and the way of connection with pulmonary circulation. Type I, branches of the bronchial artery; type Ⅱ, direct branches of aorta; type Ⅲ, indirect branch of aorta.5 APCAs of 178 were found at the branches of bronchial artery (type I,2.80%), distributed in the thoracic aorta.146 aortic direct branches (type Ⅱ,82.08%) were found, in which the APCAs mainly originated from the aortic arch, the inferior part of thoracic aorta, and aortic arch (all of direct branch). Type Ⅲ indrect APCAs were found 27 branches (15.17%). The ascending aorta and arch APCAs are all off indirect branch, and abdominal aorta derived APCAs were dominated by indirect branch (accounting for 80%), only 1 cases directly from the abdominal aorta.A total of 11 stenosis APCAs were found in this group, accounting for 6,18% of all the APCAs. Most APCAs had squirm twist before turning into lungs and have branches, which number is 168 and 139 respectively, and the proportion is 94.38% and 78.09%.2. Our reults demonstrated that 77 APCAs originated from the proximal side of accounting for 48.13%; 83 in the lateral side, accounting for 51.87%. There was no APCAs originated from the opposite side.3. We found that the connection mode of APCAs and pulmonary artery was maily central integration (total of 247 branches, accounting for 60.99%), followed by distal fusion (118 branches), a separate distribution (40 branches), accounting for 29.14% and 9.87% respectively.ConclusionsIn TOF patients, pulmonary collaterals originated maily in the middle thoracic aorta, in turn, lower segment and upper thoracic aortic arch vessels and aortic arch, abdominal aorta and ascending aorta. The majority of body-pulmonary collateral types was direct aorto-pulmonary branch, and indirect body-pulmonary collateral and Bronchial artery branches was less. Most of body-pulmonary collateral’ initial opening were without obvious stenosis. However, it is necessary to pay attention to stenosis. The most APCAs before going into lung was circuitous and has branches. The vast majority of aorto-pulmonary collateral arteries originated from the proximal side, followed by the lateral side. And no APCAs was found originating from the vest side. Central integration was the most common connection mode, followed by peripheral, single supplier are rare. In conclusion, APCAs distribution and morphology presented diversity, which should be paied attention to.ObjectiveTo explore the correlation between APCAs in tetralogy of Fallot and its pathophysiological parameters.MethodsTo analysize the CTA and ultrasound data of 61 paitents involved in TOF associated with APCAs which were collected in March 2010 to December 2014. To count the body lung branching number of per patient, measure and calculate the total area of the initial part aortopulmonary collateral vessels and the ratio beteewn total vessel area and surface area. And then to analyze its correlation with the respective age, height, weight, body surface area, the degree of pulmonary artery stenosis, VSD size, riding, the rate of right ventricular outflow tract, the inner diameter of main pulmonary arterial diameter, right ventricular wall thickness, McGoon index and other factors by correlation analysis.Results1. In our research in the correlation between APCAs number and selected pathophysiological parameters, the results showed that the number of APCAs and pulmonary artery stenosis have the highest partial correlation coefficient (r=0.432, P<0.05), and the difference was significant, while the coefficient of correlation between the number and the rest parameters are smaller than 0.19 (P>0.05) and the difference were not significant.2. The moderate positive correlations were found between the total area of APCAs and age, height, body surface area, degree of pulmonary stenosis (r=0.543,0.443, 0.576,0.674, P<0.05), a mild correlations were seen between the total area of APCAs and the weight and the ventricular septal defect (r=0.355,0.287, P<0.05), a very low positive correlation was found between the total area of APCAs and riding rate(r=0.176, P<0.05). A low negative correlation was found between the total area of APCAs and the inner diameter of right ventricular outflow tract (r=-0.368, P<0.05), a very low negative correlation was found between the total area of APCAs and the inner diameter of the main pulmonary artery (r=-0.184, P<0.05), and no significant correlations were found between it and right ventricular wall thickness and McGoon index. A strong positive correlation was found between the total area of APCAs/BSA and the degree of pulmonary stenosis (r=0.785, P<0.01). Low positive correlation were found between the total area of APCAs/BSA and ventricular septal defect, riding rate, right ventricular wall thickness(r=0.337,0.305,0.159, P<0.05). Low negative correlations were found between the total area of APCAs/BSA and the diameter of right ventricular outflow tract and main pulmonary diameter (r=0.374,0.236, P<0.05). No significant correlations were found between the total area of APCAs/BSA and the right ventricular outflow, the age, the height, the weight, the body surface area and the McGoon index.ConclusionsIn TOF patients, a moderate positive correlation was found between the number of APCAs and the degree of pulmonary artery stenosis, no obvious correlations were found between the number of APCAs and other factors. Different correlations were seen between the total area of APCAs and a variety of factors, which is caused by the interaction between anoxia due to pulmonary artery stenosis, ventricular septal defect of congenital malformations, and the increased oxygen demanding because of the body growth. Better correlations were found between the total area of APCAs/BSA and pulmonary artery stenosis, ventricular septal defect, main pulmonary trunk diameter, thickness, right ventricular outflow tract of right ventricle eliminating the related factors such as age, height, and weight. |
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