Volume 50, Issue 1 Spring 2026 JVU 501-34 | Missed Diagnosis of Focal Subclavian Artery Stenosis Discovered During Duplex Ultrasound Examination-Missed Diagnosis of Focal Subclavian Artery Stenosis Discovered During Duplex Ultrasound Examination

Missed Diagnosis of Focal Subclavian Artery Stenosis Discovered During Duplex Ultrasound Examination

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This case report details the diagnostic journey of a 54-year-old woman with a history of fibromuscular dysplasia (FMD), hypertension, and smoking, who presented with pain and discoloration in several fingers of her left hand. Initial imaging through computed tomographic angiography (CTA) and a follow-up outpatient angiogram failed to definitively identify the cause of her symptoms. The angiogram showed patent axillary and brachial arteries but sluggish distal ulnar artery flow and unclear visualization of digital arteries. She was initially suspected to have Raynaud’s disease or hypothenar hammer syndrome and was scheduled for fingertip amputation pending further diagnostics.<br /><br />One month later, a duplex ultrasound examination including wrist/brachial index and waveform analysis revealed monophasic Doppler signals in distal arteries without hemodynamically significant stenosis but elevated peak systolic velocity (656 cm/s) indicating over 75% stenosis in the proximal left subclavian artery (SCA). The proximal SCA stenosis was not fully assessed during prior imaging due to technical limitations and patient discomfort. Photoplethysmography showed severely reduced blood flow in affected digits. Subsequent chest CTA and echocardiography confirmed the proximal SCA stenosis with thrombus.<br /><br />The patient underwent successful balloon angioplasty of the left proximal SCA, improving blood flow and wrist brachial indices. Partial amputation of necrotic digits was performed. Follow-up showed symptom resolution and improved arterial pressures and waveforms.<br /><br />The report highlights that FMD, a medium-to-small vessel proliferative disease, likely caused the focal proximal SCA stenosis, leading to digital ischemia through distal embolization. It emphasizes that duplex ultrasound with velocity and waveform analysis can detect critical arterial lesions missed by CTA or angiography, especially when imaging does not fully visualize inflow vessels such as the proximal SCA. The study advocates for comprehensive vascular imaging protocols incorporating duplex ultrasound to avoid missed diagnoses and aid limb salvage in peripheral arterial disease cases associated with FMD or similar conditions.

Keywords

fibromuscular dysplasia

proximal subclavian artery stenosis

digital ischemia

duplex ultrasound

computed tomographic angiography

balloon angioplasty

Raynaud’s disease

hypothenar hammer syndrome

peripheral arterial disease

vascular imaging