A 56-year-old man, who had been followed up in the heart function clinic at St. Paul's Hospital (Vancouver, British Columbia) for ischemic cardiomyopathy, presented complaining of left-sided chest heaviness that improved with nitroglycerin. In 1998, he had an inferior myocardial infarction that was treated medically. He had a coronary angiogram at that time, the report of which was not available; however, the test did show anomalous coronary arteries. A myocardial perfusion scan showed a fixed inferior wall defect; hence, he was continued on medical therapy. His ejection fraction was 30%. An implantable cardioverter defibrillator was placed for primary prevention of sudden cardiac death.On examination, he was euvolemic and his B-type natriuretic peptide level was 26 ng/L (normal is lower than 40 ng/mL). A repeat myocardial perfusion scan revealed new inferolateral ischemia. The patient was referred for coronary angiography. This revealed an occluded right coronary artery (RCA), but selective cannulation of all the vessels was not achieved. He was referred for coronary computed tomography angiography (CCTA), which showed three coronary arteries arising from separate ostia in the right coronary sinus (RCS) (Figure 1). The occluded RCA and a septal branch were closely juxtaposed ( Figure 1C). The left anterior descending artery (LAD), which ran anterior to the pulmonary artery (PA), had a moderate (50% to 75%) stenosis proximally. There was a moderate to severe (75% to 99%) stenosis in the left circumflex artery (LCX), which took a retroaortic course. The septal branch ran an interarterial course and was normal ( Figure 2).Repeat coronary angiography, using the CCTA as a 'road map', confirmed the origin of the coronary arteries from the RCS. All vessels were imaged consecutively in one cine run (Figure 3). The LCX was a large vessel with 70% stenosis in a second obtuse marginal branch. The LAD had 50% stenosis in its mid segment and supplied collaterals to the RCA. The septal branch was normal (Figure 4). The patient was referred for surgical opinion.
DisCussionAnomalous origin of the entire coronary system from three separate ostia within the RCS is a very rare anomaly; a recent review identified 34 cases reported in the medical literature. The course of the arteries once they originate from the RCS is variable. The RCA follows the usual pathway to the right atrioventricular sulcus in all cases. The LCX is typically posterior to the aortic root, but has been reported to run anterior to the PA or along the interventricular septum. The LAD may have an anterior (anterior to the PA or right ventricular outflow tract), septal or interarterial course (between the PA and aorta). Occasionally, a fourth 'accessory' vessel will originate from the left coronary sinus, in which case it may be mistaken for the LAD or LCX at the time of coronary angiography. Correct identification of these vessels is important; otherwise, the catheterization procedure may be terminated prematurely, before visualization of the coronary vessel is...