Title : Caught in a red and blue squeeze: A plaque-free coronary crisis
Abstract:
Introduction: Anomalous origin of the right coronary artery (RCA) is a rare congenital condition, accounting for less than 1% of coronary anomalies. While many patients are asymptomatic, the anomalous course can lead to myocardial ischemia through external compression rather than from obstructive coronary artery disease. Compression primarily occurs when the RCA is positioned between the pulmonary artery and the aorta.
Case Presentation: A 44-year-old female newly diagnosed with hypertension presented with headache, dizziness and diaphoresis after taking her first dose of Nifedipine. In the ER, she was found to be in new-onset atrial fibrillation, with elevated troponins. Computed tomography (CT) with coronary angiography performed to rule out ischemia showed an anomalous RCA originating from the left cusp, compressed between the pulmonary artery and aorta, and without atherosclerotic disease. This explained her troponin elevation; therefore, surgical consultation was sought for intervention.
Discussion: The use of a calcium channel blocker, Nifedipine, induced peripheral vasodilation and may have precipitated a myocardial steal phenomenon in this patient. Additionally, collateral vessels may have been compensating for the anomalous RCA, and the vasodilatory effects potentially worsened the obstruction. Surgical correction options, including coronary artery unroofing or coronary artery bypass grafting (CABG) were considered due to high-grade narrowing along the RCA’s inter-arterial course.
Conclusion: Anomalous coronary arteries can be compressed by surrounding structures, mimicking infarction without atherosclerotic plaque. This case emphasizes considering coronary artery anatomic aberrancy as a potential cause of myocardial ischemia, especially in patients without traditional risk factors for atherosclerotic coronary artery disease.
