A coronary artery anomaly (CAA) is a congenital defect in which one or more of the coronary arteries has an abnormal origin, course, or structure. The anomaly is present from birth and arises during fetal cardiac development, when the coronary arteries fail to form in the usual pattern.
Coronary artery anomalies vary widely in their clinical significance. Many are benign variants discovered incidentally on imaging and require no treatment. However, certain types carry a risk of sudden cardiac arrest, particularly those where a coronary artery arises from the wrong side of the aorta and follows a course between the aorta and pulmonary artery (an interarterial course). During vigorous exercise, the two great arteries expand and can compress the anomalous vessel, critically reducing blood flow to the heart muscle and precipitating [ventricular fibrillation](/glossary/ventricular-fibrillation/).
Coronary artery anomalies are one of the recognised causes of [sudden cardiac arrest](/glossary/sudden-cardiac-arrest/) in young people and athletes, though they are less common than [hypertrophic cardiomyopathy](/glossary/hypertrophic-cardiomyopathy/). They may be identified during investigation of unexplained exertional symptoms, a cardiac arrest, or incidentally during [coronary angiography](/glossary/coronary-angiography/) or CT scanning performed for another reason. Cardiac MRI and CT coronary angiography are the most accurate methods for delineating the coronary anatomy.
Management depends on the type and haemodynamic significance of the anomaly. High-risk anomalies with an interarterial course are typically treated surgically by reimplanting the anomalous artery in the correct sinus of Valsalva or creating an unroofing procedure. Exercise restriction may be advised pending investigation or surgery. An [ICD](/glossary/implantable-cardioverter-defibrillator/) may be considered in survivors of cardiac arrest where surgical correction is not possible.
« Back to Glossary Index