This module covers two critical vascular surgery topics frequently tested on the USMLE: Peripheral Artery Disease (PAD) and Aortic Aneurysms. Understanding their pathophysiology, clinical presentation, diagnostic approaches, and management strategies is crucial for medical licensing exams.

Peripheral Artery Disease (PAD) is a common manifestation of systemic atherosclerosis, affecting arteries outside of the heart and brain. It most commonly involves the lower extremities.

The hallmark symptom of PAD is intermittent claudication, which is reproducible pain or cramping in the legs or buttocks that occurs with exercise and is relieved by rest. The location of the pain often corresponds to the site of arterial stenosis.

In more severe cases, patients may develop critical limb ischemia (CLI), characterized by rest pain (pain in the foot or toes when lying down), non-healing ulcers, or gangrene. Physical examination findings can include diminished or absent peripheral pulses, bruits over the affected arteries, skin atrophy, hair loss, and cool extremities.

The initial diagnostic step is often the Ankle-Brachial Index (ABI), a non-invasive test comparing blood pressure in the ankles to blood pressure in the arms. An ABI < 0.9 is diagnostic of PAD. Further imaging, such as duplex ultrasound, CT angiography, or MR angiography, may be used to delineate the extent and severity of arterial disease.

Management of PAD focuses on risk factor modification (smoking cessation, diabetes control, hypertension management, statin therapy) and medical therapy to improve symptoms and prevent progression. Antiplatelet agents (aspirin, clopidogrel) are standard. Cilostazol is a phosphodiesterase inhibitor that can improve walking distance in patients with claudication. Revascularization (angioplasty with stenting or bypass surgery) is reserved for patients with severe symptoms or critical limb ischemia.

An aortic aneurysm is a localized dilation of the aorta, a major artery that carries blood from the heart to the rest of the body. The most common type is an abdominal aortic aneurysm (AAA), followed by thoracic aortic aneurysms.

Many aortic aneurysms are asymptomatic and are discovered incidentally during imaging for other conditions. When symptomatic, symptoms depend on the location and size of the aneurysm. Abdominal aortic aneurysms may present with pulsatile abdominal mass, back pain, or abdominal pain. Rupture is the most feared complication and presents with sudden onset of severe abdominal or back pain, hypotension, and often a pulsatile abdominal mass. Thoracic aortic aneurysms can cause chest pain, back pain, hoarseness, dysphagia, or stroke-like symptoms if they involve branch vessels.

Diagnosis is typically made with imaging. Ultrasound is a sensitive and cost-effective screening tool for AAA, especially in older men and smokers. CT angiography provides detailed anatomical information and is the preferred modality for evaluating thoracic aneurysms and for surgical planning of AAAs.

Risk factor modification is also important for patients with aneurysms, similar to PAD management. Smoking cessation is paramount. For asymptomatic aneurysms below the threshold for repair, regular surveillance with imaging is crucial to monitor for growth.

Focus on differentiating PAD from other causes of leg pain. Understand the ABI and its interpretation. For aneurysms, know the typical presentation, risk factors, diagnostic imaging, and the general indications for repair based on size and symptoms. Remember that ruptured aneurysms are emergencies.