Coronary calcification masking an anomalous right coronary artery during primary percutaneous coronary intervention for inferior ST-elevation myocardial infarction

Abstract

Primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy for ST-elevation myocardial infarction (STEMI). Anomalous aortic origin of the right coronary artery (RCA) is uncommon but can substantially complicate emergency angiography and PCI when conventional catheter strategies fail. Coronary calcification increases procedural complexity. Here, we report a case in which fluoroscopic calcification may have contributed to the diagnostic uncertainty during coronary cannulation. A 74-year-old man with diabetes mellitus and hypertension presented with acute chest pain and syncope. Following the syncopal episode, no recurrent loss of consciousness or overt hemodynamic instability was documented before catheterization. Electrocardiography revealed inferior STEMI, and echocardiography revealed inferior wall hypokinesia with a left ventricular ejection fraction of approximately 40%. Angiography revealed significant disease in the left anterior descending and obtuse marginal artery. Repeated attempts to engage the RCA using multiple diagnostic and guiding catheters were unsuccessful until non-selective aortic root angiography identified the anomalous origin. Dense calcification adjacent to the expected RCA ostial region may have reinforced the initial impression of flush ostial occlusion and delayed the consideration of anomalous anatomy. During catheter manipulation, the inadvertent passage of a guidewire into an unidentified vessel provided the first clue to its anomalous origin. Non-selective aortic root angiography using a pigtail catheter identified a high-takeoff anomalous RCA, allowing for selective engagement with an Amplatz left-1 catheter. This case suggests that fluoroscopic calcification may reinforce an alternative diagnosis of ostial occlusion and delay the recognition of anomalous anatomy, highlighting a potential diagnostic challenge during primary PCI.