Anomalous coronary arteries are a rare occurrence when the arteries that supply the heart with blood (coronary arteries) do not come from the usual location on the large artery that arises from the heart (the aorta). The normal branching patterns of the coronary arteries may be abnormal as well. If the course of one of the major coronary arteries runs between the two major vessels leaving the heart (the aorta and the pulmonary artery), then there is a possibility of pinching of the coronary artery and its flow back to the heart muscle. It is possible for one of the coronary arteries (typically the left) to arise from the artery supplying the lung (pulmonary artery), rather than directly from the aorta. An increased incidence of anomalous coronary arteries is associated with certain types of congenital heart diseases.
Coronary fistulas are branches from the coronary arteries that bypass the small circulation of the heart muscle and pass directly back to one of the heart chambers or pulmonary artery. These are sometimes found incidentally if a baby or child receives an echocardiogram for another reason. Sometimes, there is enough blood flow through a fistula to create a heart murmur.
Many children with this type of defect will not have any symptoms. Some will have symptoms like chest pain or passing out (syncope) with exercise. In rare circumstances, the abnormality can result in sudden death. Infants with anomalous left coronary artery arising from the pulmonary artery (ALCAPA) may become sick, with difficulty feeding and increased work of breathing within the first few months of life due to progressive deterioration of heart function. This requires surgery to remove the coronary artery from the pulmonary artery and reattach the vessel back to the aorta. Because there is usually some damage to the heart caused by the reduced blood flow to the heart, the squeezing function of the heart may be reduced. The function of some of the valves letting blood into the heart may be affected, resulting in significant leakage of the valve. Even after reattaching the anomalous coronary artery back to the heart, the squeezing function of the heart and valve function may not recover, resulting in a cardiomyopathy (inflamed heart muscle).
Coronary arteries arising from an abnormal place may require surgical reimplantation. However, not all anomalous coronary arteries require surgery if it is felt that the blood flow to the heart is not at risk. In some situations, it can be very difficult to determine the overall risk of sudden death in a patient with anomalous coronary arteries. Many coronary artery fistulas may spontaneously go away over time. Large coronary artery fistulas may be blocked (occluded) in the catheterization lab. The child's care team may use special metallic coils or devices to fill the abnormal vessel or they may require surgical closure (ligation). If the heart has sustained severe damage, cardiac transplantation may be the only option.
- Diuretics: The most commonly prescribed diuretics are furosemide (Lasix) and thiazides (Diuril and Hydrodiuril). Diuretics act to cause the child to pass more urine, leading to a smaller blood volume – and a smaller burden on the heart to pump. Another commonly used diuretic is spiranolactone (Aldactone). It has a weak diuretic effect and is mainly used because it helps the kidneys retain potassium. Other diuretics tend to waste potassium excessively. Spironolactone may also help with heart remodeling via mechanisms that are not completely known yet.
- Inotropes: These medications, which include digoxin, help the heart pump more efficiently (stronger while using less energy).
- Afterload-reducing agents: Many of the medications in this category end with -pril. These drugs, which include captopril, are sometimes used in the treatment of congestive heart failure. When used, they act to help blood flow to the body and tissues. They may also help with heart remodeling via mechanisms that are not completely known yet.
- Beta Blockers: Many of the medications in this category end with -olol. These medications may help to regulate the stress response of the body to congestive heart failure (neurohormonal regulation).