A 43-year-old patient presented to the hospital with complaints of recurrent chest pain episodes. His initial electrocardiogram was unremarkable and cardiac biomarkers were within normal limits. The patient underwent a myocardial perfusion imaging study that revealed an apical reversible defect. During the diagnostic coronary angiogram, multiple attempts with a right Judkins catheter failed to cannulate the ostium of the right coronary artery (RCA). An ascending aortogram was thus performed and failed to opacify the RCA or reveal any aortic pathology. Subsequently, cannulation of the left coronary artery (LCA) revealed a severe stenosis in the proximal left anterior descending artery, which this was subsequently stented. A dominant left circumflex artery was noted; it continues in the atrioventricular groove and is seen in the expected course of the RCA, however, there is no communication with the aortic cusp (Figures 1, 2 and 3). This was an angiographically normal vessel.
The overall incidence of coronary artery anomalies in the general population is approximately 1%. An anomalous RCA has an incidence of 0.26% in the general population. Of these, the anomalous RCA may originate from the left sinus of Valsalva (0.1%), posterior sinus of Valsalva (0.003%), LCA (0.009%), thoracic aorta (0.15%) or the pulmonary artery (0.002%). This case is illustrative of an absent RCA.