Congenital coronary anomalies are rare, and are usually diagnosed incidentally during coronary artery angiograms or on postmortem evaluations. The actual incidence is unknown, but has been reported to be between 0.2% and 1% in angiographies, and approximately 0.3% in autopsies (1
). Congenital coronary anomalies that may be associated with potentially serious events (such as ectopic coronary origin from the opposite aortic sinus and the presence of a single coronary artery) are very rare. Because the diagnosis of these malformations by routine screening is difficult, the anomaly is often diagnosed retrospectively at autopsy. These malformations may not be detected by ergometric testing or myocardial scintigraphy. It has been reported that transthoracic echocardiography may be helpful, but transesophageal echocardiography is more sensitive (4
). Coronary angiography remains the standard for diagnosis and leads the principle for treatment. Multidetector computed tomography has recently been reported to play a diagnostically complementary role with coronary angiography. There is also an advantage in detecting the relationship of anomalous vessels to great vessels and other structures. Accurate recognition and documentation of coronary anomalies and their course is essential to avoid inadequate therapy.
The clinical significance of congenital coronary anomalies is usually nonspecific. Their clinical presentation may be asymptomatic, or may cause myocardial infarction and sudden death (5
), depending on the relationship with the aorta and pulmonary artery; increased sudden death has been reported in patients with a single coronary artery and left main coronary artery that lies between the aorta and the pulmonary artery (8
). The mechanism involved may be an acute angle and folding, or occlusion by angulation, coronary spasm and mechanical compression (9
). In other cases, the anomaly can present as a benign course in those without atherosclerotic changes in the coronary tree. In case 1, the RCA was dominant and the anomalous left main artery originating from the right coronary sinus coursed in the anterior aspect of the pulmonary artery. The course was benign, and medical management was recommended. However, whether the symptom of chest discomfort was due to myocardial ischemia from slow coronary flow is unknown. The relationship between alternations in the coronary flow and clinical presentation remains unclear.
Therapeutic options for anomalous coronary arteries include medical management, coronary angioplasty and surgery. Surgical approaches include direct repair of the anomalous origin in the aortic root or coronary bypass. Coronary angioplasty is technically difficult, with only scattered cases reported in the literature (10
). Patients with a single left coronary artery with congenital absence of the RCA usually had a benign clinical course in previous studies (5
). However, cases that required surgical bypass have been reported by Chou et al (13
). An increased risk of atherosclerosis with acute-angle take-off malformations has been reported (14
). Another study reported no relationship between a single coronary artery and atherosclerosis (15
). In such a congenital anomaly, there is no consensus regarding therapeutic strategy and atherosclerosis formation, because the information and clinical experience are limited. The two patients with a single coronary artery discussed in the present article both remained stable with medical management during follow-up at our outpatient clinic for more than one year.