Peripheral Artery Disease
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Introduction
PAD is a substantial burden on people and populations.
It is often asymptomatic, underdiagnosed.
The Case of...
Causes and Risk Factors
PAD can occur
Acute causes
Acute embolic occulsion, occuring in anyone. Emboli most often originate in the heart, following atrial fibrillation, myocardial infarction, or myxoma. Other causes include aneurysm.
Acute thrombotic occlusion is an acute on chronic disease following years of atherosclerotic buildup, often following dehydration, hypercoagulability, or other thrombotic situations.
trauma
Chronic Causes
Atherosclerosis, usually occurring in older patients, accounts for the majority of cases of chronic PAD. Risk factors include:
- smoking
- increased cholesterol
- hypertension
- diabetes mellitus
Pathophysiology
Atherosclerosis develops over years with vessel damage, inflammation, and plaque buildup. As the lumen diameter decreases, velocity increases. At rest, distal structures receive sufficient blood, but with exercise and increased oxygen demand, symptoms arise.
Atherosclerosis commonly occurs in more than one site, causing stroke and coronary artery disease.
PAD normally develops over time. As vascular supply decreases, collaterals develop, slightly increasing perfusion. Worsening disease. further decreases
Normally, one joint below the site of arterial disease is affected.
Pain evetually develops while at rest, 1-20 years after claudication occurs. Rest pain is especially bad at night due to the lack of gravity. Walking a few steps or sleeping in a chair improves symptoms as gravity assists in foot perfusion.
Dependent rubor represents the accumulation of venous blood in areas
Signs and Symptoms
PAD can be remembered by the five P's:
- pain
- pallor
- paresthesia
- pulselessness
- paralysis
- history
- physical exam
History
- intermittent claudication: pain, tightening, or cramping, brought on by exercise and releived by rest.
Physical Exam
Bruits can be heard over arteries in aorta or peripheral vessels
Pallor in elevated limbs
A reddened, mottled foot should be raised to distinguish between severe dependent rubor and lobster foot.
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Ankle-brachial index (systolic) can be taken using doppler flow
- normal: >0.91
- mild-moderate: 0.4-0.9
- severe: <0.4
CTA
MRA
angiogram
Differential Diagnosis
Treatments
Treatment depends on chronic or acute etiology, disease severity, and patient co-morbidities.
Lifestyle
exercise, quitting smoking, diet modifaction.
Surgery
Chronic PAD has a relative indication while patients have claudication. Grafts have a limited lifetime, and patients will often die of other causes (ie stroke, myocardial infarction) before PAD becomes too severe.
and an absolute indication when the limb is threatened. Not everyone with chronic PAD
Acute disease
Acute emboli are treated by balloon catheterization and embolectomy.
Acute thrombosis is treated with arthroplasty or bypass.
Consequences and Course
With severe PAD, ongoing ischemia can lead to ulcers,
- severe dependent rubor
- lobster foot: petechiae following vessel rupture; can cover foot. Will not drain when raised
- gangrene: dead tissue
Once rest pain develops, it is only weeks to months before total occlusion occurs and gangrene sets in. A threatened limb accordingly
Additional Resources
Topic Development
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