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Reports of incidental coronary artery abnormalities range from 0.6% to 1.3% during routine angiography, and 0.3% in autopsies. An isolated single coronary artery is a particularly rare congenital anomaly. Clinical presentation is usually nonspecific; patients with an isolated single coronary anomaly may present with symptoms such as angina, myocardial infarction or sudden cardiac death. The therapeutic options depend on origin, course and termination. It is dangerous and potentially lethal if a single coronary artery is associated with obstructive coronary artery disease. Two cases of anomalous origin of a coronary artery from a single Valsalva sinus without any other visible coronary artery detected by aortography are reported.
A 61-year-old man complained of chest tightness on exertion for approximately one month. The patient had a history of systemic hypertension, diabetes and hypercholesterolemia as risk factors for coronary artery disease; he underwent regular follow-up with medication at an outpatient clinic. He had no history of tobacco or alcohol use. Physical examination of his cardiovascular system was unremarkable. His resting electrocardiogram was normal. He underwent exercise treadmill testing (Bruce’s protocol) and the results revealed ST depression in precordial lead V5 at 4 min of the test. Echocardiography revealed normal left ventricular function. Exercise thallium-201 myocardial scintigraphy was subsequently performed; the results revealed decreased perfusion at the inferior wall during the stress phase, with partial recovery during the resting (redistribution) phase. The patient was referred for catheterization evaluation due to suspected coronary artery disease with angina. After coronary angiography was performed via the right radial artery, the team was unable to cannulate the ostium of the left main coronary artery. Despite several attempts, the left coronary artery could not be visualized. The use of a 5 Fr right coronary Judkins catheter technique for selective injection of the right coronary angiography revealed a dominant right coronary artery (RCA). The contrast medium flowed along the large RCA very slowly and, because of its large diameter, appeared as a faint image. Following the course of the normal RCA, the RCA proceeded via a posterolateral segment into the course of the left circumflex (LCX) branch and followed a retroaortic course. The final segment of the RCA was quite prominent, with a posterior descending artery and abundant branches of a right ventricular artery supplying the apical region of the left ventricle (Figure 1, upper panel). Aortic root angiography revealed that the ostium of the anterior interventricular branch originated near the orifice of the RCA, then crossed in front of the pulmonary artery and presented with an anterior course. Aortography also confirmed that there was not any additional left coronary artery from the left coronary sinus (Figure 1, lower panel). The coronary artery was free of atherosclerotic changes and no intervention was planned. The patient underwent regular follow-up with medication control for more than two years.
A 75-year-old woman was found lying unconscious on the floor of her home for an unknown length of time. After awakening, she complained of anterior chest tightness at rest. She had a history of systemic hypertension and diabetes as risk factors for coronary artery disease, with poor compliance. She had no history of tobacco or alcohol use. Physical examination of her cardiovascular system was unremarkable. Her resting electrocardiogram in the emergency room showed atrial fibrillation. Biochemistry analysis demonstrated elevated levels of troponin-I (1.06 μg/L; reference range 0 μg/L to 0.04 μg/L), with abnormal levels of total creatine kinase (483 U/L; reference range 30 U/L to 170 U/L) and creatine kinase-myocardial isoenzyme (61 U/L; reference range 0 U/L to 16 U/L). Echocardiography revealed normal left ventricular function without regional wall motion abnormalities. The patient was referred for catheterization evaluation due to suspected acute coronary syndrome. Coronary angiography was performed and revealed a small calibre of left anterior descending artery (LAD) and a dominant LCX artery. In addition, the LCX artery extended and branched to supply RCA territory (Figure 2, upper panel). The RCA was not apparent by several approaches, and absence of the RCA was confirmed by aortogram (Figure 2, lower panel). There were no other associated cardiac anomalies. Percutaneous transluminal coronary angioplasty is technically difficult and surgical reconstruction was considered but refused by the family. The patient underwent regular follow-up with medication control.
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 (1–3). 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 (5–7), 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 (10,11). Patients with a single left coronary artery with congenital absence of the RCA usually had a benign clinical course in previous studies (5,12). 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.