Overview of Coronary Artery Ectasia
Ectopic coronary arteries originating from the pulmonary arteries and the aorta, and from the common carotid artery and the innominate artery are extremely rare and often associated with severe cardiac malformations. The most common ectopic origin of the pulmonary arteries is the left coronary artery, with rare right coronary artery originating from the pulmonary arteries, bilateral coronary arteries originating from the pulmonary arteries, left coronary artery circumflex branch originating from the pulmonary arteries, and paracoronary arteries or conical coronary arteries originating from the pulmonary arteries. Those with both coronary arteries originating from the pulmonary artery die of severe myocardial ischemia and hypoxia a few days after birth and are rarely diagnosed clinically. Ectopic origin of the left coronary artery from the pulmonary artery. The left coronary artery originates from the pulmonary artery, but there is no abnormality in its branch distribution or travel.
Etiology.
The disease is a congenital heart condition in which the left and right coronary arteries issue from the aorta under normal conditions and provide the blood needed by the heart. They open deep into the aortic root, in the left and right aortic sinuses, respectively. If the aortic valve attachment margin line as the boundary, the aortic sinus can be divided into sinus and sinus, the vast majority of openings (80% to 91%) are in the sinus, the rest of the openings in the sinus or sinus line. In the case of anomalies, it is more common for the coronary arteries to originate from the pulmonary artery and the aorta, and in a few cases from the common carotid artery and the innominate artery, often accompanied by other severe malformations.
Symptoms
The child may have no abnormal manifestations within 1 month of birth, and may begin to present with myocardial ischemia and hypoxia 2 to 3 months after birth, with shortness of breath induced by breastfeeding or crying, irritability, pale or cyanotic lips, profuse sweating, fatigue, increased heart rate, coughing, wheezing, and so on. It is a symptom due to angina pectoris and heart failure. In a few cases with very rich left and right coronary collateral circulation, the presentation of angina pectoris and chronic congestive heart failure is delayed until about 20 years of age, and a continuous murmur is often heard in the precordial region in these cases, and mitral valve insufficiency is also more severe. Physical examination showed poor growth and development, thinness, no weight gain, increased respiration, enlargement of the cardiac turbid boundary, increased heart rate, hepatomegaly, jugular venous filling, lung field rales and other signs of heart failure, and systolic murmurs produced by mitral valve closure insufficiency could be heard in the apical region. In patients with abundant coronary collateral circulation, a soft continuous murmur can be heard in the precordial region.
Examination
1. Chest X-ray examination
It shows that the heart shadow is significantly enlarged, the left heart margin is full and elevated, the heart tip is rounded and blunt, protrudes outward and downward to the left axilla and covers the spine backward, the lung field is congested with blood vessels, but the pulsation is weak.
2. Electrocardiography
The left precordial leads show ST-segment elevation, and there are often signs of left ventricular hypertrophy.
3. Right heart catheterization
In cases with rich coronary collateral circulation, the right coronary blood from the aorta enters the left coronary artery through collateral circulation and flows into the pulmonary artery, so the oxygen content of pulmonary artery blood increases, and left-to-right shunt can be shown at the level of the pulmonary artery, and the pressure of the pulmonary artery can also be increased.
4. Echocardiography
Echocardiography shows enlargement of the left ventricle and a marked decrease in myocardial contractility. Cross-sectional echocardiography and ultrasound pulsed Doppler may show ectopic origin of the left coronary artery from the pulmonary artery.
5. Serum enzyme measurements
Elevated creatine phosphokinase, lactate dehydrogenase, and glutamate aminotransferase may be detected.
6. Radionuclide myocardial imaging
Radionuclide myocardial imaging with 201TI can show that the myocardium is not visible in the anterolateral area of the heart.
7. Selective cardiac angiography
Cardiac angiography is a reliable method to confirm the diagnosis of ectopic origin of coronary arteries. Aortography and selective right coronary angiography show that only the right coronary artery – branch originates from the aorta, the right coronary artery is significantly thickened, and the contrast agent fills the left coronary artery in the reverse direction and then flows back into the pulmonary artery. Selective left ventriculography often reveals an enlarged left ventricular cavity, markedly reduced left ventricular contractility, and hypokinesis of the anterior wall of the left ventricle. Selective left ventriculography is also useful in the diagnosis of mitral valve insufficiency. In some cases, the left coronary artery may be visualized when contrast is injected into the pulmonary artery.
Diagnosis
The diagnosis is made on the basis of etiology, clinical manifestations and laboratory tests.
Treatment
The natural prognosis for cases of ectopic origin of the left coronary artery from the pulmonary artery is poor, with the majority of patients dying of left heart failure within the first year of life, and the majority of these patients dying within the first 2 months of life. In cases where there is abundant collateral circulation, the child may survive into adulthood, but often dies of chronic congestive heart failure or sudden death due to the gradual worsening of ischemic lesions in the left ventricle. Therefore, once the diagnosis is clear, surgical treatment should be pursued.
1. Left coronary artery ligation
Left coronary artery ligation is easy to operate, but it is only applicable to cases with rich collateral circulation and large left-to-right shunt. After ligation, the left-to-right shunt and coronary blood-stealing phenomenon have disappeared, myocardial blood supply has been improved, heart failure has improved or even disappeared, the heart shadow has shrunk, growth and development have been normal, and the body weight has increased. The mortality rate of ligation in infant cases can be as high as half, and the mortality rate of surgery in children over 2 years old is significantly reduced.
2. Left subclavian artery – left coronary artery anastomosis
This procedure can be performed with or without extracorporeal circulation. Those who do not apply extracorporeal circulation enter the chest through the 4th intercostal incision outside the left anterior chest, dissect and free the root of the left coronary artery and the left subclavian artery, ligate and cut off the left subclavian artery and its vertebral artery branches at the top of the chest cavity, turn the proximal section of the left subclavian artery downward, and then use the proximal section of the subclavian artery to make a side-to-side anastomosis with the left coronary artery after the ligation of the root of the left coronary artery. In some cases, the anastomosis can be kept patent for a long time by cardiovascular angiography. However, if the length of subclavian artery is not enough, the anastomosis cannot be performed, and the anastomosis is too tense after the operation or the subclavian artery is twisted, which may cause the anastomosis to be not patent, affecting the therapeutic effect, and thus it is not popularized in the clinic.
3. Ascending aorta-left coronary artery connection surgery
Surgery to connect the ectopic origin of the left coronary artery to the ascending aorta, to establish a normal coronary blood source, so that the coronary artery blood supply to restore the normal physiological state, in recent years, with the development of extracorporeal circulation technology has been increasingly popularized and applied. There are several methods for this type of surgery, most of which need to be operated under myocardial protection measures such as extracorporeal circulation combined with moderate hypothermia or deep hypothermia and cardiac cold arrest fluid.
(1) Ectopic origin left coronary artery grafting into the ascending aorta This procedure is reasonably designed, meets normal physiologic requirements, and has good therapeutic effects; however, if the left coronary artery is not long enough, and the tension after graft implantation into the ascending aorta is too great, other surgical procedures need to be used.
(2) Aorto-left coronary artery pars plana grafting with the saphenous vein In the case of end-to-end anastomosis, the origin of the left coronary artery is freed from the wall of the pulmonary artery, and double ligated with sutures, and then the common trunk of the left coronary artery is incised longitudinally, and the saphenous vein crosses over the common trunk of the pulmonary artery and anastomoses with the left coronary artery in an anterior direction. The end-to-end anastomosis can be performed without extracorporeal circulation. Since the coronary artery and saphenous vein are small and the vessel wall is weak in infants and young children, postoperative complications such as obstructive lesions or lumen enlargement are more likely to occur, and the long-term patency rate and therapeutic effect have yet to be observed in the follow-up.
(3) Pulmonary artery endarterectomy This procedure has only been in clinical use for more than 10 years. Its advantage is that there is no need to dissect out the left coronary artery and perform difficult incision and closure of the small coronary arteries, especially for cases where the left coronary artery opening is located in the left wall of the pulmonary artery, thus the length of the left coronary artery is relatively short.
Prevention
The disease is a congenital disorder, so there is no effective prophylaxis. The natural prognosis is poor, most of them die within 2 months after birth. Cases with rich development of collateral circulation can survive into adulthood, but they often die of chronic congestive heart failure or sudden death due to the gradual aggravation of ischemic lesions in the left ventricle. Therefore, once the diagnosis is clear, active surgical treatment is the only effective measure to prevent further deterioration of the disease.