Coronary anomalies originating from the pulmonary artery
Introduction
Coronary artery abnormalities originate from the pulmonary artery Coronary artery originating from the pulmonary artery refers to a coronary artery or its branches (left anterior descending coronary artery or left circumflex coronary artery) or two coronary arteries originating from the proximal pulmonary trunk or very few originating from the proximal right pulmonary artery. During normal development, the pulmonary artery trunk also grows coronary buds, but usually degenerates. The left or right coronary plexus is not connected to the aortic sinus bud, but abnormally connected with the pulmonary artery bud, the coronary artery abnormality originates from the pulmonary artery. basic knowledge The proportion of sickness: 0.002%-0.003% Susceptible people: good for infants and young children Mode of infection: non-infectious Complications: congestive heart failure, mitral regurgitation, sudden death
Cause
Coronary artery abnormality originates from pulmonary artery etiology
(1) Causes of the disease
The normal development of the coronary arteries must be caused by the aortic sinus to grow coronary buds and connect to the subepicardial coronary vascular plexus. The subepicardial vascular plexus is the intramyocardial vascular plexus formed by the venous structure, during normal development. In the middle, the pulmonary artery trunk also grows coronary buds, but usually degenerates. The left or right coronary plexus is not connected to the aortic sinus bud, but abnormally connected with the pulmonary artery bud, the coronary artery abnormality originates from the pulmonary artery.
(two) pathogenesis
1. Embryonic development abnormal coronary artery development must have aortic sinus to grow coronary buds, and connect with subepicardial coronary vascular plexus, subepicardial vascular plexus is a structure of myocardial vascular plexus formed with vein structure During normal development, the pulmonary artery trunk also grows coronary artery buds, but usually disappears. The left or right coronary artery plexus is not connected with the aortic sinus bud, but abnormally connected with the pulmonary artery bud, the coronary artery abnormality originates from the pulmonary artery. According to the literature, the normal development of the two coronary arteries is divided into three parts (Figure 1).
1 The formation of sinusoids, in the early stage of human embryo, there are loosely arranged myocardial fibers in the heart wall, there are sponge-like long cylindrical sinusoids between the myocardial cells, the myocardial interstitial is filled with cardiac glial, and the blood supply of cardiomyocytes comes from the blood of the heart chamber. With the growth of human embryos, the myocardial wall is thickened, the layers of the myocardium are tightly attached to each other, the myocardial gel gradually disappears, and the heart wall is firm. At this time, the circulation must be established to meet the needs of the active myocardium. This cycle depends on the sinusoids. The intramyocardial sinusoidal cavity will form intramural coronary arteries, capillaries and veins, and the coronary veins will be drained to the coronary sinus. On the 22nd day of the human embryo, the heart begins to beat, and a fluctuation cycle occurs in the next few days.
2 The development of the subepicardial coronary plexus, Hutchins et al pointed out that the earliest form of the coronary vascular bed is a group of blood islands, located in the apical interventricular sulcus, this blood island continues to grow in the heart groove, the number increases, The outer layer is wrapped with endothelial cells to form the original coronary vascular plexus including the right, left anterior descending and left circumflex coronary vascular plexus. When the blood island appears, the heart colloid gradually disappears between the endocardium and the myocardium, and the sinusoidal space forms a coronary vein. Drain to the coronary sinus and connect with the subdural coronary vascular plexus.
3 Coronary artery bud growth, when the arterial trunk is completely separated from the aorta and pulmonary artery, coronary artery buds grow in the aorta and pulmonary trunk, and the number of reports varies from 4 to 6 (4-6).
There are two mechanisms for the connection of normal aortic buds to coronary vascular plexus:
1 When the coronary vascular plexus is close to the arterial trunk, the growth of coronary buds is induced.
2 The left sinus and right sinus of the aorta are saddle-shaped, where the tension is the largest and the coronary bud is emitted. The normal left and right coronary vascular plexus are connected with the left and right sinus buds respectively, forming a two-coronary system. Two or one branch of the coronary plexus or a branch thereof is connected to the pulmonary artery bud, and a coronary artery abnormality originates from the pulmonary artery.
2. Pathological anatomy
Coronary artery abnormalities originate in the pulmonary artery and can occur in 2 or 1 branch and its branch coronary artery. Soloff reports 5 types, including left coronary artery, right coronary artery, two coronary arteries, additional coronary artery and left circumflex coronary artery originating from pulmonary artery. (Fig. 2), sometimes the left anterior descending coronary artery can also originate from the pulmonary artery.
Left coronary artery abnormalities originate from the pulmonary artery and are most commonly found in the clinic. The opening positions are different. According to the aortic side from the non-facing sinus, the pulmonary sinus is divided into right, left and non-facing sinuses. Castaneda finds the origin of left coronary artery abnormality. The opening can be located anywhere in the pulmonary trunk or near the branch of the pulmonary artery. The most common opening is located in the right sinus of the pulmonary artery (posterior sinus) (Fig. 3), followed by the non-facing sinus of the pulmonary artery, the posterior wall of the pulmonary artery and the right pulmonary artery, and the left coronary artery. The origin is particularly rare in the anterior wall of the pulmonary artery. Turley reported that 11 cases of left coronary artery originated from the pulmonary artery, 3 of which originated from the right sinus of the pulmonary artery (posterior sinus), 2 cases were non-facing to the sinus, 1 case was in front of the root of the pulmonary artery and 2 cases were in the posterior, in the pulmonary artery. There were 2 cases between the bifurcation and the right circumflex artery, and 1 case between the pulmonary bifurcation and the left pulmonary artery (Fig. 4).
Smith found that 11 cases of left coronary artery originated from the pulmonary artery by necropsy, 5 cases originated from the right (posterior) sinus of the pulmonary artery, 1 case was adjacent to the pulmonary valve junction, 1 case was in the middle of the right sinus, 3 cases were above the sinus-tube junction, and 1 case was right. Pulmonary artery.
In the infantile left coronary artery originating from the pulmonary artery, the abnormal origin opening is obviously enlarged, and the coronary artery becomes smaller when descending to the interventricular sulcus, becoming a thin wall blood vessel larger than normal, which can be mistaken for the vein, and the right coronary artery originates from the right aorta. The sinus also has an enlarged opening, and the right coronary artery is thick and distorted, sometimes forming an aneurysm-like change, and the collateral circulation is less in the infant, which may cause heart failure due to myocardial ischemia, and is abundant between the adult left and right coronary arteries. The collateral circulation of the blood vessels causes a left-to-right shunt of the right coronary artery through the left coronary artery to the pulmonary artery; due to the phenomenon of "coronary blood stealing", the left ventricular myocardium may be further damaged. Likar reports the right and left coronary artery lateral branches. There are 4 circulating blood vessels:
1 The right coronary artery has a large conical diameter Vieussen ring to the left anterior descending coronary artery;
2 in the front of the right ventricle from the edge of the right coronary artery to send a few small blood vessels to the left anterior descending coronary artery;
3 from the particularly large posterior descending coronary artery through the interventricular septum many small blood vessels to the full-length left anterior descending coronary artery;
4 There is a small blood vessel in the left posterior interventricular septum from the distal segment of the right coronary artery (Fig. 5).
In infants, the heart enlarges, especially the left atrium and left ventricle are severely enlarged and hypertrophied. The anterior papillary muscles are atrophied with scars, and the attached tendons are shortened. It is also reported that the papillary muscles can also be affected, and the left ventricle sees extensive endocardial elasticity. Fibroplasia, anterior mitral regurgitation, due to myocardial infarction, left ventricular anterior lateral wall and apex thinning and scarring, sometimes forming ventricular aneurysm, often with intracavitary thrombosis, however, in infants due to myocardial ischemia, are different The degree of cardiac insufficiency, but the left ventricular function improved significantly after the two-coronary system repair.
In adults, the left coronary artery wall is thinner like a vein, and the heart is also enlarged, but relatively smaller than the baby, often without endocardial fibroelastosis, but the anterior and external papillary muscles have scars and calcification, sometimes involving the adjacent left ventricle and The mitral valve produces extensive calcification.
Mitral regurgitation has the following pathogenesis mechanisms:
1 papillary muscle dysfunction, papillary muscle extensive fibrosis and sometimes calcification.
2 endocardial fibroelastosis involving the mitral valve device, as well as chordae fusion and shortening.
3 left ventricular fibrosis leads to a significant expansion of the left ventricle and mitral annulus to produce mitral regurgitation, myocardial ischemia in infants can be restored can also cause mitral regurgitation, but can be alleviated after two-coronary system repair Or disappear.
Right coronary artery abnormality originates from the pulmonary artery and is rare in clinical practice. The left coronary artery originates from 1/10 of the pulmonary artery, and the prognosis is also good. The right coronary artery abnormality originates from the pulmonary artery and is usually located in the upper pulmonary artery and the right coronary artery wall is thinned. Coarse, abundant collateral circulation vessels, from the left coronary artery through the collateral circulation vessels and right coronary artery to the left-right shunt of the pulmonary artery, but there are also a few cases of myocardial ischemia and sudden death.
Coronary artery abnormalities on both sides originate from the pulmonary artery and are particularly rare, often dying after birth.
Left anterior descending coronary artery abnormalities originate from the pulmonary artery is rare, only 8 cases reported in the literature, including 1 case died 3 months after birth, the remaining 7 cases survived 18 to 55 years old; 5 cases have myocardial ischemia, 1 case of left ventricular anterior wall Infarction, 1 case of mitral regurgitation and papillary muscle dysfunction, only a few cases of left circumflex coronary artery, often originated from the right pulmonary artery, combined with abnormal arterial catheterization, main-pulmonary septal defect, ventricular septal defect and method Luo tetralogy and so on.
3. Pathophysiology
Agustsson divides the direction of blood flow from the left coronary artery to the pulmonary artery into two types: one is adult, a rich collateral circulation between the two coronary arteries, and coronary blood flow to the pulmonary artery; the other is infant type It was confirmed that there was no reverse blood flow in this abnormal coronary artery.
During embryonic development, aortic pressure and oxygen saturation are the same as those of pulmonary arteries. Patients with this deformity have satisfactory myocardial perfusion, and no stimuli produce collateral circulation vessels (Fig. 6). Normally, in the first week after birth, the left ventricle is under high pressure. After high-resistance load, myocardial cell proliferation and hypertrophy and new coronary artery formation maintain myocardial stress and promote left ventricular growth. However, after the arterial catheter is closed, the pulmonary artery contains unsaturated blood, and the pulmonary artery pressure drops rapidly below the systemic circulation pressure. At this time, the left ventricle, which requires great oxygen, is infused by low pressure and unsaturated blood; at first, the collateral circulation is small, and the left ventricle myocardial blood vessels dilate, causing the resistance to decrease and the blood flow to increase, but the coronary artery reserve is quickly depleted, resulting in Myocardial ischemia, myocardial ischemia is temporary, recurrent, but myocardial oxygen needs to be further increased, leading to myocardial infarction of the anterior and posterior lateral wall of the left ventricle, the left ventricle gradually enlarges, the wall of the wall becomes thin, heart failure occurs, left ventricle and two Mitral annulus enlargement and papillary muscle dysfunction and myocardial infarction cause mitral regurgitation, heart failure often due to apex Incomplete closure, the two form a vicious circle. The adult type gradually forms a rich collateral circulation between the right coronary artery of normal origin and the left coronary artery of abnormal origin. The right coronary artery is thickened, but the left coronary artery is connected to In the low-pressure pulmonary artery, the collateral circulation of blood to the pulmonary artery, but not to the high-resistance myocardial blood vessels, resulting in coronary artery-to-pulmonary stealing. This kind of stealing has been confirmed by Sabiston. The experiment proves that when the left coronary artery originates abnormally. When obstructed, the distal coronary artery pressure increased; angiography revealed the right coronary artery through the collateral circulation, the left coronary artery to the left-to-right shunt of the pulmonary artery, this sub-flow only accounted for a small part of the cardiac output, but equivalent The blood flow in the coronary arteries is very large. In about 15% of cases, the heart muscle can maintain heart function during rest or even activity, but arrhythmia and sudden death can also occur.
In cases where the right coronary artery originated from the pulmonary artery, the left coronary artery was thick, the blood flowed through the collateral circulation, and the right coronary artery to the left-right shunt of the pulmonary artery. In only a few cases, myocardial ischemia and sudden death occurred.
Prevention
Coronary artery abnormalities originate from pulmonary artery prevention
Prevention of various possible pathogenic factors, vigorous promotion of prenatal and postnatal care, prevention of viral infection in early pregnancy, reduction of uterus by adverse physical and chemical factors, prenatal genetics or chromosome examination if necessary, to prevent problems before they occur.
Complication
Coronary artery abnormalities originate from pulmonary artery complications Complications Congestive heart failure mitral regurgitation
About 65% to 85% of patients with left coronary artery abnormalities originating from the pulmonary artery died of congestive heart failure within 1 year of life, and complications such as mitral regurgitation and sudden death may occur.
Symptom
Coronary artery abnormalities originate from pulmonary artery symptoms Common symptoms Dyspnea cold sweat shock syncope heart failure hernia
Symptom
Infants rarely develop symptoms within 2 months after birth because the high pulmonary artery pressure prevents the shunt of the pulmonary artery and coronary artery stealing. The myocardial infarction is gradually formed rather than suddenly. The baby has obvious symptoms for the first time. In the case of feeding and activities, there is shortness of breath, and then the complexion and pale extremities are pale, cold sweat is in shock state, symptoms are relieved during hernia, and the onset time is shortened, often prolonged by 5 to 10 minutes, and then asymptomatic after careful care for several days. Repeated seizures may have discomfort, may be angina pectoris, many patients do not have the above symptoms, early symptoms and signs of heart failure, a small number of children have serious symptoms in infants, gradually improved and asymptomatic, large children and adults can Asymptomatic or dyspnea, syncope and labor angina and other symptoms, in adults, typical myocardial infarction and heart failure symptoms are rare.
2. Signs
Cardiac failure signs are optional, and the heart of the baby tends to expand, mainly left ventricular enlargement, such as left ventricular failure and significant pulmonary hypertension, can produce right ventricular enlargement and pulmonary heart disease 2nd heart sound hyperthyroidism, with mitral valve closure When the time is not complete, the first heart sound is weakened or disappeared, and the apical area is rushed. The murmur of the mitral insufficiency may be optional. The continuous murmur on the left upper edge of the sternum may be patent ductus arteriosus or malformation of the coronary artery to the pulmonary artery. Left-to-right shunt.
Clinical symptoms, signs, X-rays, electrocardiograms, and echocardiography can be diagnosed in most cases. A few atypical cases are diagnosed by ascending aortic angiography or selective coronary angiography, and provide direct imaging evidence for surgery.
Examine
Coronary artery abnormalities originate from the examination of the pulmonary artery
1. Chest X-ray: In the baby's heart shadow, the left atrium and left ventricle are mainly enlarged, and there are signs of pulmonary congestion or pulmonary edema. In large children and adults, the heart is slightly larger, both lungs Wild is clear.
2. Electrocardiogram: Electrocardiogram of left coronary artery abnormality originated from pulmonary artery has characteristic changes, which is helpful for clinical diagnosis. In the infant, ECG of left ventricular anterior lateral wall myocardial infarction can appear, and left chest lead shows Q wave ST segment. Ascending, as well as left ventricular hypertrophy, showed an ECG of old left ventricular anterior lateral wall myocardial infarction in large children and adults, with ST segment changes and T wave inversion.
3. Echocardiography: Color Doppler echocardiography has gradually replaced cardiac catheterization and cardiovascular angiography, which is the diagnostic method for this abnormality. Multiple sections can prove that the left coronary artery or right coronary artery originates from the pulmonary artery. The blood flow from the coronary artery to the large blood vessel replaces the normal from the aorta to the coronary artery, but the exact location of the coronary artery originating from the pulmonary artery is difficult to determine, and the pericardial transverse sinus is often confused with the left coronary artery.
Two-dimensional echocardiography of the left coronary artery originating from the pulmonary artery shows that the right coronary artery is particularly large, and the heart chamber, especially the left ventricular cavity enlargement and activity is weakened, the left ventricular wall abnormal activity and mitral regurgitation, left ventricular papilla The myocardium and the adjacent endocardium of the left ventricle are enhanced by ultrasound imaging due to fibrosis and fibroelastosis, and the left ventricular systolic function includes a decrease in left ventricular ejection fraction and shortening rate.
4. Cardiac catheterization and cardiovascular angiography: Cardiac catheterization and cardiovascular angiography should be performed when echocardiography cannot confirm this malformation. In symptomatic infants, cardiac catheterization demonstrates low cardiac output and left ventricular filling pressure. Increased, often accompanied by varying degrees of pulmonary hypertension, in children with asymptomatic, cardiac output and pulmonary artery pressure are normal, only left ventricular end-diastolic pressure is slightly elevated, left-right shunt at the pulmonary artery level, sub-flow There may be fewer, even if there is no shunting, the diagnosis of this malformation is not excluded.
Aortic root angiography showed a significant enlargement of the right coronary artery. If there were abundant collateral circulation vessels, the contrast agent from the left coronary artery to the pulmonary artery, cardiovascular angiography showed a significant enlargement of the left ventricle and left atrium, and left ventricular anterior lateral free wall activity. Attenuation and mitral regurgitation, left ventricular angiography demonstrated a significant enlargement of the left ventricle and ventricular aneurysm with a large apex.
Diagnosis
Coronary artery abnormality originates from the diagnosis and identification of pulmonary artery
The main diseases that need to be identified with this disease are endocardial elastic fiber hyperplasia, myocarditis, etc. Most of the endocardial elastic fiber hyperplasia electrocardiogram has only left ventricular hypertrophy without myocardial infarction, although myocarditis has myocardial infarction performance, but Often accompanied by arrhythmia.
