Abstract Body (Do not enter title and authors here): Background:
Aortic stenosis (AS) is a common and serious valve disease in the elderly, often diagnosed using echocardiography. However, certain conditions can mimic AS, leading to diagnostic challenges. This case highlights the importance of a comprehensive vascular assessment in patients with atypical symptoms and echocardiographic findings suggestive of severe AS.

Case Presentation:
An 80-year-old female presented with progressive dizziness and double vision over the past few months. She reported a long-standing history of lower blood pressure in her right arm compared to her left. Her medical history was significant for HER2-positive intraductal breast cancer treated with neoadjuvant chemotherapy. An echocardiogram performed two months prior to presentation, using a Pedoff probe, indicated severe AS with a peak systolic velocity of 5.1 m/sec, a mean systolic gradient of 50 mm Hg, and an aortic valve area of 0.6 cm.

Investigations: Given the discrepancy in blood pressure between her arms and the wide open aortic valve on the echo which dosen't corrleate with the doppler numbers, CTA neck and chest was performed, revealing a dense calcific plaque causing severe stenosis at the origin of the left subclavian artery. An angiogram confirmed >75% stenosis of the left subclavian artery, which was treated with angioplasty and stent placement, resulting in <10% residual stenosis.

Outcome: Following the intervention, a repeat echocardiogram showed only mild calcification of the aortic valve with a mean gradient of 4 mm Hg, significantly lower than the previous findings.

Discussion: This case underscores the potential for subclavian artery stenosis to mimic severe AS on echocardiography, particularly when using the Pedhoff probe. It highlights the need for clinicians to consider vascular anomalies in the differential diagnosis when echocardiographic doppler findings do not correlate with clinical symptoms or with the structural apperance of the valves.

Conclusion: Comprehensive assessment and consideration of alternative diagnoses are crucial in patients with suspected severe AS, especially when using Doppler echocardiography. Awareness of the potential for subclavian artery stenosis to cause false-positive echocardiographic findings can prevent unnecessary interventions and guide appropriate management.