What is the most common etiology of carotid and renal artery stenosis?

• A. Thrombosis
• B. Atherosclerosis
• C. Vasculitis
• D. Fibromuscular Dysplasia

Answer: (B)

Atherosclerosis is the most common cause of carotid and renal artery stenosis. Lipid-rich plaques accumulate in the arterial intima, slowly growing and often calcifying, which narrows the vessel lumen over years. This process affects large arteries like the carotids and renal arteries, especially in people with risk factors such as age, smoking, hypertension, diabetes, and dyslipidemia, leading to reduced cerebral or renal perfusion and related symptoms. In contrast, thrombosis would cause sudden blockage rather than gradual narrowing; vasculitis involves inflammatory narrowing that is less common overall; fibromuscular dysplasia is a nonatherosclerotic condition seen more in younger individuals, often with a bead-like appearance on imaging.