Abstract Title: Double jeopardy: A case of anomalous RCA arising from left coronary sinus with inter-arterial course complicated by significant advanced atherosclerotic disease

Background: Coronary artery anomalies are developmental variations with an estimated incidence of 1-5.6%. While often benign, certain anomalies can lead to significant ischemic events, arrhythmias, and sudden cardiac death. The anomalous origin of a right coronary artery (RCA) from the left coronary sinus with an inter-arterial course between the aorta and pulmonary artery is a high-risk "malignant" variant. This case highlights the diagnostic and management complexities when this congenital anomaly is compounded by advanced acquired atherosclerotic disease

Case presentation: A 64-year-old female with a history of hypertension, diabetes, and endstage renal disease on peritoneal dialysis presented with acute hypoxic respiratory failure, hypertensive emergency, and elevated troponins. Her hospital course was complicated by atrial fibrillation and a suspected subacute stroke. Initial electrocardiograms showed a left ventricular hypertrophy with strain pattern, later evolving to deep T-wave inversions. A left heart catheterization was performed for ongoing chest pain, revealing an 80% heavily calcified proximal left anterior descending artery lesion, which was treated with shockwave atherectomy and a drug-eluting stent. The RCA could not be engaged. A subsequent coronary computed tomography angiography (CTA) identified an anomalous RCA originating from the left coronary sinus. The vessel had a high-risk inter-arterial course between the aortic and pulmonary artery roots and demonstrated extensive, long-segment, calcified atherosclerotic plaque causing possible severe obstructive luminal narrowing.

Discussion: This case represents a "double jeopardy" scenario, where a high-risk congenital anomaly is superimposed with severe acquired coronary artery disease. The inter-arterial course of the RCA creates a risk for dynamic, exertional compression between the great vessels, while the fixed, calcified atherosclerotic plaque independently obstructs blood flow. This combination dramatically elevates the risk for myocardial infarction and sudden cardiac death, as even minor dynamic compression can become hemodynamically critical in the presence of a pre-existing stenosis. Determining functional significance of such lesions becomes pivotal. While surgical revascularization with coronary artery bypass grafting (CABG) is the definitive treatment to address both the dynamic and fixed obstructions when significant, patient had symptomatically improved. For further risk stratification, outpatient Stress test and Ambulatory monitoring were pursued which were negative for inducible ischemia and ventricular arrhythmias. The decision was then made to pursue aggressive medical management. This case underscores the importance of advanced imaging like coronary CTA in diagnosing complex coronary anatomy and highlights the challenges in managing patients with combined congenital and advanced acquired cardiovascular pathologies. We anticipate newer technologies like CT FFR might prove beneficial in such cases as they may provide crucial functional context to anatomical abnormalities, enabling a more comprehensive diagnostic assessment.