Coronary steal

Introduction Coronary bloodletting is a clinical manifestation of babies born with coronary ectopic origins occurring 2 to 3 months after birth. Common origins of coronary ectopic origin are from the pulmonary artery and aorta. The origin of the common carotid artery and the innominate artery is extremely rare and often accompanied by severe cardiac malformation. Brooks first reported 2 patients in 1885. The most common origin of ectopic origin in the pulmonary artery is the left coronary artery. In addition, the rare right coronary artery originates from the pulmonary artery. Both coronary arteries originate from the pulmonary artery. The left coronary artery circumflex origin originates from the pulmonary artery and the coronal artery or conical coronary artery. Originated from the pulmonary artery. Bilateral coronary arteries originate from the pulmonary arteries and die within a few days after birth due to severe myocardial ischemia and hypoxia, and are rarely diagnosed clinically. Left coronary artery ectopic originates from the pulmonary artery. The left coronary artery originated in the pulmonary artery, but its branch distribution and path were normal. The incidence rate was only 1 in every 300,000 live births and 0.26% in congenital heart disease.

Cause

The left coronary artery originates from the left or posterior valve sinus of the pulmonary artery. It is divided into a front descending branch and a gyroscopic branch from 5 to 6 mm from the starting part. There are collateral circulation branches between the left and right coronary arteries, but the number varies. The origin and branch of the right coronary artery are normal. The left ventricle is hypertrophied and highly enlarged, and the enlargement of the apical region of the left ventricle is more obvious. The left ventricle is extensively fibrotic, with the most prominent subendocardial area, often with myocardial infarction. Fibrotic lesions sometimes present with focal calcification, and subendothelium exhibits varying degrees of fibroelastic tissue proliferation. Due to extensive fibrosis or even calcification of the papillary muscles, the papillary muscles are dysfunctional. Endocardial fibroelastic tissue hyperplasia caused by cerebral cord fusion and shortening and left ventricular fibrosis leading to enlargement of the left ventricle and mitral annulus, often presented with mitral regurgitation.

Pathophysiology: The pathophysiological effects of left coronary artery ectopic origin from pulmonary artery depend on the pressure difference between systemic circulation and pulmonary circulation, and the extent and extent of collateral circulation between left and right coronary arteries. In the fetal and neonatal period, the left and right ventricular pressure and blood oxygen content are equal, and the pulmonary circulation resistance is similar to the systemic circulation resistance. Therefore, the left coronary artery originating from the pulmonary artery can obtain the same perfusion pressure and oxygen supply as from the aorta. The development and growth of the fetus does not have any effect. The pulmonary circulation resistance decreased and the pulmonary artery pressure dropped to normal from 7 to 10 days after birth. At the same time, pulmonary oxygen saturation is also reduced to about 70%, blood hematocrit is also reduced from 70-80% before birth to about 40% after 3 months of birth, and hemoglobin content is reduced, so ectopic The origin of the left coronary artery not only decreased the perfusion pressure to 2.7 ~ 6.7KPa (20 ~ 50mmHg), but also significantly reduced the oxygen content of the perfused blood, resulting in insufficient myocardial oxygen supply in the left coronary artery blood supply area, hypertrophic lesions in the left ventricle, heart The subendocardial region of the myocardium presents extensive fibrosis due to ischemia and hypoxia. The survival of an infant after birth depends on the development of the collateral circulation between the left and right coronary arteries. When the collateral circulation is fully developed, the baby can survive; if the collateral circulation is not fully developed, it will lead to myocardial infarction and death. Excessive collateral circulation is derived from the right coronary artery of the aorta to transport blood flow, through the collateral circulation into the left coronary artery and pulmonary artery, resulting in left to right shunt, resulting in congestive heart failure and coronary vascular steal syndrome, about 80 ~90% of patients die of congestive heart failure or myocardial infarction within 1 year after birth. Only a small number of patients have abundant collateral circulation between left and right coronary arteries, and most of the myocardium includes left ventricular palpebral and most ventricular septum. And the blood supply to the left ventricular wall from the right coronary artery may survive into adulthood.

Coronary artery ectopic originates from the pulmonary artery and is most common.

an examination

Related inspection

Coronary angiography coronary CT examination

[clinical manifestations]

The infant can have no abnormal performance within 1 month after birth. It can start to show myocardial ischemia and hypoxia after 2 to 3 months of birth. When feeding or crying, it induces shortness of breath, irritability, pale lips or cyanosis, sweating and fatigue. Increased heart rate, cough, wheezing, etc. may be caused by angina and heart failure. In a small number of cases with very rich left and right coronary collateral circulation, symptoms of angina pectoris and chronic congestive heart failure can be delayed until the age of 20 years. In these cases, continuous murmurs and mitral regurgitation are often seen in the anterior region. Also more serious.

Physical examination: poor growth and development, small size, weight loss, increased breathing, increased heart and voice, increased heart rate, hepatomegaly, jugular vein filling, lung field rales and other signs of heart failure, apical area can be heard Systolic murmur produced by mitral regurgitation. A coronary collateral circulation is abundant, and a soft continuous murmur can be heard in the anterior region.

[Auxiliary inspection]

Chest X-ray examination: the heart shadow is significantly increased, the left heart is full and bulging, the apex is blunt, protruding outward to the left iliac crest, and covering the spine backwards, the blood vessels in the lungs are congested, but the pulsation is weak.

Electrocardiogram examination: often showed anterior external wall myocardial infarction signs, L1 and AVL leads showed Qr type and T wave inversion, V5V6 showed deep Q wave, often accompanied by T wave inversion, left anterior ventricular lead showed ST segment elevation And often have signs of left ventricular hypertrophy.

Right heart catheterization: Coronary collateral circulation is rich in cases. The blood from the right coronary artery from the aorta enters the left coronary artery and then flows into the pulmonary artery through the collateral circulation. Therefore, the blood oxygen in the pulmonary artery increases, and the left to right can be displayed at the pulmonary artery level. The shunt can also increase pulmonary artery pressure.

Echocardiography: showing left ventricular enlargement, myocardial contractility is significantly reduced. Sectional echocardiography and ultrasound pulse Doppler examination can show that left coronary artery ectopic originates from the pulmonary artery.

Serum enzyme assays revealed elevated levels of creatine phosphokinase, lactate dehydrogenase, and aspartate aminotransferase.

Radionuclide myocardial imaging: myocardial imaging with 201TI showed that the myocardium was not developed in the lesion area of the anterior and posterior parts of the heart.

Selective cardiac angiography: Angiography is a reliable method for the diagnosis of the origin of coronary ectopic. Aortic angiography and selective right coronary angiography showed that only one of the right coronary arteries originated in the aorta, the right coronary artery was significantly thickened, and the contrast agent filled the left coronary artery in the opposite direction and then returned to the pulmonary artery. Selective left ventricular angiography often showed enlargement of the left ventricular cavity, a significant decrease in left ventricular contractility and a decrease in left ventricular anterior wall motor function. Selective left ventricular angiography is also helpful in diagnosing mitral regurgitation. In some cases, when the contrast agent is injected into the pulmonary artery, the left coronary artery may be developed.

Differential diagnosis

Coronary artery stealing occurs in children with congestive heart failure, and needs to be differentiated from endocardial fibroelastosis, but also with primary dilated cardiomyopathy, coronary aneurysm, Kawasaki disease, pre-cardiac Area continuity murmurs and other identification.

I. Endocardial fibroelastosis

Endocardial fibroelastosis (EFE), also known as endocardial sclerosis, has not yet been elucidated. It is a common type of primary cardiomyopathy in children, also known as primary endocardial fibroelastosis. Congenital heart disease such as aortic coarctation, aortic stenosis, aortic valve atresia and other endocardial fibroelastosis, called secondary endocardial fibroelastosis, its clinical significance depends on the primary heart deformity. Clinical manifestations are mainly congestive heart failure, often occurring after respiratory infections.

The general symptoms can be classified into three types according to the severity of the symptoms:

(1) fulminant: sudden onset of illness, sudden dyspnea, vomiting, refusal to eat, perioral cyanosis, pale, irritability, tachycardia. There are scattered wheezing or dry rales in the lungs, the liver is swollen, and edema is also seen, both of which are signs of congestive heart failure. A small number of children presented with cardiogenic shock, which showed symptoms such as irritability, gray complexion, cold and cold limbs, and accelerated and weak pulse. This type of sick child is more than 6 months old and can cause sudden death.

(2) acute type: onset is also faster, but the development of congestive heart failure is not as sharp as the fulminant, often complicated by pneumonia, accompanied by fever, wet rales in the lungs. Some children develop cerebral embolism due to the loss of the wall thrombus. Most died of heart failure, and a small number of treatments were relieved.

(3) Chronic type: The incidence is slightly slow, and the age is more than 6 months. Symptoms are acute, but progress is slow, and some children's growth and development are affected. It can be relieved after treatment, and it can live in adulthood. It can also die from repeated heart failure.

Second, primary dilated cardiomyopathy

This type is characterized by left or ventricular or bilateral ventricular enlargement with cardiac hypertrophy. Ventricular systolic dysfunction, with or without congestive heart failure. Ventricular or atrial arrhythmia is more common. The condition is progressively aggravated and death can occur at any stage of the disease. It can occur in all ages, but it is mostly in middle age. The onset was slow, and the heart was enlarged at the initial examination, and the heart function was compensated without conscious discomfort. Symptoms gradually appear after a period of time, sometimes more than 10 years. Symptoms are mainly congestive heart failure, with air urgency and edema being the most common. Initially, after anxious labor or exhaustion, there will be shortness of breath during mild activities or rest, or a paroxysmal urgency at night. Because of low blood output, patients often feel weak. Physical examination sees the heart rate accelerate, the apex beats to the left and down, there may be a lifting pulsation, the heart sounds the sound to the left to expand, often can hear the third or fourth sound, when the heart rate is fast, the horse is running. Due to the enlargement of the heart chamber, there may be a systolic murmur caused by a relative mitral or tricuspid regurgitation, which is alleviated after the improvement of cardiac function. Most of the blood pressure is normal, but the blood pressure is lower in the advanced cases, the pulse pressure is small, and the diastolic blood pressure can be slightly increased in the presence of heart failure. The appearance of alternating veins suggests left heart failure. The pulse is often weak. In heart failure, there may be rales in the base of the second vein. In the case of right heart failure, the liver enlarges, and the appearance of edema starts from the lower limbs. Pleural effusion and ascites are not common in patients with advanced disease. A variety of arrhythmia can occur, for the first time or the main performance, and a variety of arrhythmia combined to form a more complex heart rhythm, can occur repeatedly, sometimes stubborn. High atrioventricular block, ventricular fibrillation, sinus block or pause can lead to A-S syndrome, which is one of the causes of death. In addition, there are still embolizations in the brain, kidney, lungs, etc.

Third, Kawasaki disease

The disease is an acute systemic vasculitis, which is inflammation of the blood vessel wall, and can progress to vasodilation (aneurysm), mainly affecting the coronary artery (the blood vessels supplying the heart). However, not all children develop an aneurysm. Most patients present with acute symptoms without complications.

The disease begins to manifest as unexplained hyperthermia, lasting at least 5 days, and the child is often very annoyed. Fever can be accompanied by or subsequent conjunctivitis (eye congestion), children with rash or secretions can have a variety of rash manifestations, such as measles or scarlet fever-like rash, urticaria, pimples and so on. The rash is mainly distributed in the trunk and limbs, and often occurs in the anal perineal area. Oral changes are characterized by bright red lips, chapped, tongue congestion, often referred to as "yangmei tongue" and pharyngeal congestion of hands and feet can be affected, manifested as palm and plantar congestion and swelling. After these performances (approximately two to three weeks), characteristic peeling of the fingers and toes is followed.

More than half of the patients present with enlarged lymph nodes in the neck, usually a single lymph node with a diameter of at least 1.5 cm.

Sometimes, other symptoms such as joint pain and / or joint swelling, abdominal pain, diarrhea, irritability and headache can also be seen that cardiac involvement is the most serious manifestation of Kawasaki disease, because it may lead to long-term complications. Heart murmurs, arrhythmias, or echocardiographic abnormalities can be found. Each layer of the heart can have a degree of inflammatory response, namely pericarditis (inflammation of the membrane surrounding the heart), myocarditis (inflammation of the myocardium), and valve involvement. However, the main feature of this disease is the formation of coronary aneurysms.

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