Unexpected anatomical obstacle detected during emergency coronary intervention: type A interrupted aortic arch in an adult.

Interrupted aortic arch is a rare congenital heart anomaly characterised by a complete discontinuity between the ascending and descending aorta, accounting for approximately 1-1.5% of CHDs. Its incidence in live births ranges from 3 to 20 per million. Survival into adulthood is only possible with the presence of a well-developed collateral circulation. In this case, a 49-year-old male patient presented with acute anterior myocardial infarction, and during emergency coronary angiography, discontinuity of the aortic arch was noticed. The procedure was successfully completed via radial access after femoral access failed. Subsequent thoracic computed tomography angiography confirmed the diagnosis of Type A interrupted aortic arch and revealed widespread collateral arterial circulation. No blood pressure difference was detected between the right-left arms and lower extremities, and the patient remained asymptomatic. This case demonstrates that this rare anomaly in adults can be incidentally detected during emergency procedures and that radial access is an effective alternative in overcoming anatomical obstacles.