Overview of Coronary Artery Origins
Coronary artery origin from the pulmonary artery is defined as the origin of 1 coronary artery or its branches (left anterior descending coronary artery or left circumflex coronary artery) or 2 coronary arteries from the proximal pulmonary artery trunk or, rarely, from the proximal right pulmonary artery.
Etiology
Normal development of the coronary arteries must be from the aortic sinus grow coronary artery buds, and subepicardial coronary artery vascular plexus connection, the subepicardial vascular plexus is with the venous structure formed by the endomyocardial vascular plexus traffic, in the course of the normal development of the pulmonary artery trunks also grow coronary arterial buds, but usually degeneration disappeared, left or right coronary artery plexus did not connect with the aortic sinus buds, and the pulmonary artery buds are abnormally connected to the formation of the Anomalous origin of the coronary arteries from the pulmonary arteries.
Symptoms
1. Symptoms
Symptoms are rare in infants during the first 2 months of life because high pulmonary artery pressure prevents shunting to the pulmonary arteries and coronary artery tapping. Myocardial infarction develops gradually rather than suddenly. In infants, the first noticeable symptoms occur during breastfeeding and activity, with shortness of breath, followed by pallor of the face and endings of the extremities, cold sweat and a state of shock. Symptoms are relieved by belching, and the duration of the attack is shortened and often prolonged for 5 to 10 minutes, and then asymptomatic for several days under careful care. There may also be recurrent episodes of discomfort, possibly angina pectoris. There are many patients who do not present with these symptoms and present early with signs and symptoms of heart failure. A small number of children have severe symptoms as infants that gradually improve and become asymptomatic later. Larger children and adults may be asymptomatic or have symptoms such as dyspnea, syncope, and exertional angina. In adults, typical symptoms of myocardial infarction and heart failure are rare.
2. Signs
Signs of heart failure may or may not be present. In infants, the heart tends to be enlarged, predominantly in the left ventricle. If there is left ventricular failure and marked pulmonary hypertension, the right ventricle may enlarge and the second heart sound in the pulmonary valve area may be hyperactive. In the presence of mitral valve insufficiency, the 1st heart sound is diminished or absent as well as the presence of a gallop rhythm in the apical region. The murmur of mitral insufficiency may or may not be present. A continuous murmur at the left upper sternal border may be a left-right shunt from the coronary artery to the pulmonary artery in the presence of an incomplete or malformed ductus arteriosus.
Examination
1. Chest X-ray
In infants, the heart shadow is markedly enlarged, with predominantly enlarged left atrium and left ventricle and signs of pulmonary congestion or edema. In older children and adults, the heart shadow is slightly larger and both lung fields are clear.
2. Electrocardiogram
The electrocardiogram in cases of left coronary artery anomalies originating from the pulmonary artery has characteristic changes that help in the clinical diagnosis. In infants, an electrocardiogram of left ventricular anterolateral wall myocardial infarction may be seen, with Q-wave ST-segment elevation in the left precordial lead and left ventricular hypertrophy. In older children and adults, an electrocardiogram of an old LV anterolateral wall myocardial infarction is seen, with S-T segment changes and T wave inversion.
3. Echocardiography
Color Doppler echocardiography has gradually replaced cardiac catheterization and cardiovascular angiography as the standard diagnostic method for this malformation. Multiple views can demonstrate anomalous origin of the left or right coronary artery from the pulmonary artery. Two-dimensional echocardiography of an anomalous origin of the left coronary artery from the pulmonary artery reveals an unusually large right coronary artery, as well as enlarged and diminished chambers of the heart, especially the left ventricular chamber, abnormal left ventricular wall motion, and mitral valve insufficiency. The left ventricular papillary muscles and the endocardium adjacent to the left ventricle are enhanced on ultrasound due to fibrosis and elastofibrillar hyperplasia. Left ventricular systolic function including left ventricular ejection fraction and shortening is decreased.
4. Cardiac catheterization and cardiac angiography
Cardiac catheterization and cardiovascular angiography should be performed when echocardiography does not confirm the diagnosis of the malformation. In symptomatic infants, cardiac catheterization demonstrates low cardiac output and increased left ventricular filling pressures, often with varying degrees of pulmonary hypertension. In asymptomatic older children, cardiac output and pulmonary artery pressures were normal, with only mildly elevated left ventricular end-diastolic pressures. There is a left-right shunt at the level of the pulmonary arteries, which may be small, even though the absence of a shunt does not exclude the diagnosis of this malformation.
Aortic root angiography shows marked enlargement of the right coronary artery, and contrast from the left coronary artery to the pulmonary artery if there are abundant collateral circulation vessels. Cardiac angiography demonstrates marked enlargement of the left ventricle and left atrium, as well as decreased left ventricular anterolateral free wall motion and mitral valve closure insufficiency. Left ventriculography demonstrated marked enlargement of the left ventricle and a large apical ventricular wall tumor.
Diagnosis
The diagnosis is confirmed in most cases by clinical symptoms, signs, X-rays, electrocardiograms and echocardiograms, and in a few atypical cases with the help of ascending aortography or selective coronary angiography. It also provides a direct imaging basis for surgery.
Complications
Infants with anomalous origin of the left coronary artery from the pulmonary artery in 65% to 85% of patients die of congestive heart failure within the first year of life. Complications such as mitral valve insufficiency and sudden death can also occur.
Treatment
Preventive measures are taken against various possible causative factors, strongly promoting eugenics, avoiding viral infections in early pregnancy, minimizing exposure of the uterus to adverse physical and chemical factors, and performing prenatal genetic or chromosomal tests when necessary. Coronary artery anomalies originating from the pulmonary artery require surgical correction and treatment.
1. Indications
All patients with an anomalous origin of the left coronary artery from the pulmonary artery have an indication for surgery and should be operated on as early as possible, even if they are asymptomatic. Because 90% of these patients die within 1 year of age, it is advocated that surgery be performed in infancy once the diagnosis is confirmed. Because only surgery can solve the problem of pulmonary artery stealing blood from the left coronary artery, avoid myocardial ischemic injury, prevent papillary muscle dysfunction from occurring, improve the left heart function, and prevent the occurrence of heart failure or sudden death.
2. Anesthesia and extracorporeal circulation methods
(1) Normal temperature general anesthesia is used for simple left coronary artery ligation.
(2) low-temperature extracorporeal circulation For left subclavian artery-coronary artery anastomosis, ascending aorta-left coronary artery bypass grafting, left coronary artery grafting and left coronary angioplasty of pulmonary artery internal channel.
3. Surgical methods
(1) Ligation is suitable for cases with abundant collateral circulation. Direct ligation of the left coronary artery at its connection with the pulmonary artery can eliminate the phenomenon of coronary artery blood-stealing. However, the operation has a high mortality rate and a high incidence of late sudden death, so it is seldom used at present.
(2) Left subclavian artery – left coronary artery anastomosis Ligation of the proximal left coronary artery first. Free the left subclavian artery, cut off from the distal end, and turn down the left subclavian artery to anastomose with the left coronary artery. The advantage of this procedure is that it is autologous and can grow with age. The disadvantage of this procedure is that the left subclavian artery is often not long enough, resulting in folding and twisting of the left subclavian artery, which affects the smooth flow of blood.
(3) Ascending aorta-left coronary artery bypass grafting The autologous saphenous vein or subclavian artery is used as the grafting material for ascending aorta-left coronary artery bypass grafting. There are two types of operation: ① extracardiac ascending aorta – left coronary artery bypass grafting. ②Transpulmonary artery within the ascending aorta, left coronary artery bypass grafting.
(4) Left coronary artery grafting with the tip of the left coronary artery This procedure is applicable to the left coronary artery from the posterior wall of the pulmonary artery trunk or the left pulmonary artery. The main pulmonary artery is cut off at the level of the anomalous coronary artery opening, and the left coronary artery is cut off from the wall of the pulmonary artery with its tip and transplanted directly into the root of the ascending aorta, and then the two ends of the pulmonary artery are anastomosed end to end.
(5) Left coronary artery angioplasty with intra-pulmonary access is indicated in cases where the left coronary artery opening is far from the aorta. A 4-5 mm hole is punched between the main and pulmonary arteries, and the anterior wall of the pulmonary artery trunk is used to cut a long vascular sheet, which is sewn around the opening of the left coronary artery to form a vascular conduit and anastomosed to the ascending aorta.
Prognosis
Sixty-five to 85% of infants with anomalous origin of the left coronary artery from the pulmonary artery die of congestive heart failure within the first year of life. After infancy, many patients continue to die of congestive heart failure due to ischemic left ventricular cardiomyopathy. However, after survival to 40 years of age, the risk of death due to heart failure decreases, and patients survive to 50 to 60 years of age, with intermittent sudden death. In adult patients, there is predominantly myocardial ischemia and fibrosis with intermittent extensive myocardial calcification. In most of these patients, the left ventricular ejection fraction is only mildly decreased or normal.