Anomalous left coronary artery (ALCA) occurs when the left coronary artery arises from the pulmonary artery instead of its usual site of origin, the aorta. It is a rare problem comprising <1% of congenital heart defects.
The coronary arteries are the blood vessels that supply the heart muscle with red or oxygen-rich blood. There are usually two large coronary arteries that arise from the aorta, one from the right side (1) and one from the left side (2). Sometimes, for unknown reasons, when the heart and blood vessels are forming, the left coronary artery (3) arises from the pulmonary artery (4). Right after birth, the pressure is the pulmonary artery is high so that enough blood flow through this vessel to supply the heart muscle with oxygen. Over the first two months of life, the pressure in the pulmonary artery drops and so does the blood flow through this vessel.
The decreased amount of oxygen-rich blood leads to damage to the heart muscle cells. As a result, the heart is not able to pump as much blood as the body needs. This causes symptoms of congestive heart failure such as poor feeding, slow growth, clammy sweating, and poor growth. Often these symptoms are seen between 2 and 6 months of age, but they can occur during early infancy or rarely, during later childhood.
Symptoms: As described above, the onset of symptoms of congestive heart failure most often occurs within the first 6 months of life. Possible symptoms include irritability, lethargy, rapid breathing, clammy sweating, poor feeding and slow growth.
Physical findings: The physical findings of congestive heart failure in children include slow weight gain, rapid breathing and heart rates, and enlarged liver. In older children, there may also be swelling around the eyes and/or feet. Often a heart murmur is present.
Medical tests: The suspected diagnosis is usually made by an echocardiogram. Sometimes, a heart catheterization may is needed to confirm the diagnosis. The electrocardiogram is usually abnormal. On chest x-ray, the heart is usually quite enlarged. An oxygen saturation test is used to measure the blood oxygen levels.
ALCA is a serious problem and requires surgery as soon as possible after the diagnosis is made. The aim of surgery is to connect the ALCA with the aorta. The precise surgery depends on the exact location of the ALCA. Sometimes, it can be moved, along with a button of tissue, from the pulmonary artery and sewn into the aorta. If the ALCA is located too far away from the aorta to move, a "tunnel" is made from the aorta to the ALCA.
The long-term health effects reflect the degree of damage to the left ventricle. If the problem was found early, before much damage occurred, and the surgery was successful, there are few long-term health effects. If the left ventricle was damaged, there may be ongoing symptoms of congestive heart failure. As a result, the child may have low stamina, and may need to be restricted from sports. The symptoms are often treated with medicines such as digoxin, diuretics, blood pressure lowering medicines, and/or blood thinners. If the damage if very severe, a heart transplant may be needed.
SBE prophylaxis: Children with ALCA are at increased risk for subacute bacterial endocarditis (SBE). This is an infection of the heart caused by bacteria in the blood stream. Children with heart defects are more prone to this problem because of the altered flow of blood through the heart and/or abnormalities of the valves. SBE can occur after dental work or medical procedures on the GI or respiratory tract because these procedures almost always result in some bacteria entering the blood. The problem can usually be prevented by taking an antibiotic before these procedures.
Exercise guidelines: An individual exercise program is best planned with the doctor so that all factors can be included. In children with ALCA, sports guidelines are based on the degree of heart damage. If there is some damage, children are usually restricted from vigorous or competitive sports but can participate in recreational sports. It is important for them to be able to self-limit their activity, that is, to rest whenever they feel the need to do so. The children can usually participate in gym class but should be allowed to self-limit their level of exertion and they should not be graded (which could increase the pressure to exceed their natural limits).
Herlong JR. Congenital coronary artery anomalies. In Garson A, Bricker JT, Fisher D & Neish S. The Science and Practice of Pediatric Cardiology, Vol II, Philadelphia PA: Williams & Wilkins: Baltimore, MD. 1998; 1652-1657.
Yuh D & Reitz B. Miscellaneous defects. In Reitz B & Yuh D, ed. Congenital Cardiac Surgery, 2002. New York: McGraw Hill,172-174.