AssessmentsPeripheral artery disease: Pathology review
USMLE® Step 1 style questions USMLE
A 75-year-old man comes to the clinic with persistent leg pain with exertion. Three months ago, the patient was found to have an ankle-brachial index of 0.6, and he was started on atorvastatin, chlorthalidone, and aspirin. Since then, the patient has successfully quit smoking and has participated in a supervised exercise therapy program where he has achieved a 10 lb (4.5 kg) weight loss. The pain, characterized by aching in the right thigh and buttock after walking more than 3 blocks, has not improved. The patient’s temperature is 37.0°C (98.6°F), pulse is 80/min and regular, respirations are 20/min, blood pressure is 130/75 mmHg, and BMI is 32 kg/m2. Pulses in the right femoral artery are diminished compared to the left. Which of the following therapies is most appropriate for this patient?
Content Reviewers:Yifan Xiao, MD
Tariq is a 52-year-old individual who presents to the clinic complaining of left leg pain.
He describes the pain as “cramping” and mostly located in his calf.
He also mentions that the pain comes every time he walks from his home to the supermarket, and is relieved when he rests.
On physical examination, there is a noticeable decrease in hair growth on the left side compared to the right, and the skin appears dry and shiny.
There is no leg swelling, and there’s no back pain.
Similar to coronary artery and cerebrovascular disease, the development of an atherosclerotic plaque that narrows or completely occludes an artery is the number one cause of peripheral artery disease, and so these diseases often coexist together.
So on the exam, an important clue may be an individual with a past medical history of a myocardial infarction or a stroke.
The symptoms of peripheral artery disease depend on how bad the occlusion is.
In the early stages of the disease individuals may be completely asymptomatic.
One of the first symptoms is intermittent claudication.
This is characterized by cramping pain in the affected area that comes about during exercise, and is relieved with rest.
Individuals often describe a specific and often consistent distance that brings about the pain, such as walking 2 blocks.
The location of the pain can also help give a clue about which artery is occluded.
For example, hip claudication indicates aortic or iliac artery occlusion, whereas calf claudication points towards femoral or popliteal artery occlusion.
In addition to claudication, chronic limb ischemia may produce some physical changes.
This includes a decrease in the skin temperature, called poikilothermia.
Also, hair and nail growth decrease, sensation can be lost.
On physical exam, the pulse distal to the obstruction is weak, and there’s diminished capillary refill in the affected area.
As the arterial narrowing worsens, individuals begin to complain of pain at rest.
This is classically worse at night when the individual is sleeping, and gets better when they stand up or hang their leg off of the bed, due to the effect of gravity on blood flow.
Eventually, the peripheral tissue dies, which manifests as gangrene and ulcers.
The end-stage manifestation is critical limb ischemia, which includes pain at rest as well as tissue loss in the form of gangrenes and ulcers.
Critical limb ischemia is limb-threatening if operative intervention is not performed.
For diagnosis, when there’s suspicion of peripheral artery disease, an ankle-brachial index test, or ABI is performed.
Normally, both pressures should be equal, and so the ratio should be equal to 1.
In individuals with intermittent claudication, the ABI usually lies somewhere between 0.4 and 0.9, since the blood pressure in the ankle is decreased.
In severe peripheral artery disease, usually when the individual begins to develop resting pain, the ABI is less than 0.4.
After doing the ABI, the diagnosis is further confirmed with imaging, such as ultrasound or CT angiography.
For treatment, lifestyle changes like exercise programs and diet are the first steps.
For medication, Cilostazol, a phosphodiesterase inhibitor, can directly dilate the arteries, easing symptoms.
In addition it’s an antiplatelet which can prevent platelet aggregation and decrease the risk of thrombosis.
Even without Cilostazol, they should still take an antiplatelet medication like aspirin as prevention for coronary artery disease and stroke.
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- "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
- "Rapid Review Pathology" Elsevier (2018)
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- "2016 AHA/ACC Guideline on the Management of Patients With Lower Extremity Peripheral Artery Disease: Executive Summary" Journal of the American College of Cardiology (2017)
- "Cilostazol for intermittent claudication" Cochrane Database Syst Rev (2014)