Peripheral arterial disease pathophysiology

Peripheral arterial disease is characterized by a narrowing of the peripheral blood vessels leading to decreased blood flow to the limbs. The most common underlying cause of PAD is atherosclerosis. As the atherosclerosis progresses with time beyond the ability of the vessels to compensate for it, mainly upon increased blood demand in exercise, symptoms of claudication start.

• Peripheral arterial disease is characterized by narrowing in the peripheral blood vessels leading to decreased blood flow to the limbs. The most common underlying cause of PAD is atherosclerosis.
• Atherosclerosis is a systemic disease that progresses over time and might involve the aorta, coronary, carotid and the medium-sized peripheral arteries.
• When the atherosclerosis involves the peripheral limb blood vessels, the blood flow to the limbs is compromised. Such atherosclerotic plaques tend to occur at vessel bifurcations due to both impaired atheroprotective mechanisms and turbulant blood flow. At the beginning the vessels try to adapt by metabolic and myogenic autoregulation. At this stage, the patient might be asymptomatic. As the atherosclerosis progresses with time beyond the ability of the vessels to compensate for it, mainly upon increased blood demand in exercise, symptoms of claudication start.
• Critical limb ischemia symptoms like rest pain occur when the stenosis in the arteries is so severe that the resting metabolic requirements of the tissues are not met by the arterial perfusion.^[1]
• When the atherosclerotic plaques become unstable, thrombi form on top of a ruptured plaque located at a disease arterial segment. Atherothrombosis is the term currently used to describe this process.

Below is an image illustrating the narrowing of the blood vessel due to the presence of the atherosclerotic plaque:

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