What causes PAD
PAD is caused by the same thing that can cause a heart attack or stroke, blocked arteries.
A blocked artery is caused by a blood clot.
Blood clots occur in the arteries because fatty material (called plaque) that is deposited in the arterial wall ruptures. The plaque builds up (a process called atherosclerosis) and narrows the artery; when this plaque ruptures, the blood clot forms over the rupture and can block the artery. The process of a blood clot forming over the plaque rupture is called
atherothrombosis.
Atherosclerosis causes progressive narrowing of the arteries where plaque is deposited in the arterial wall. Atherothrombosis is when plaque ruptures and blood clots are formed that cause the blockage of an artery.
There are four common stages in the development of PAD:
Stage 1: Artery narrowing
The arteries begin getting more narrow but with no other symptoms. PAD develops gradually and can remain unnoticed for long periods. In many cases, it only causes symptoms in the elderly. However, the rate at which the disease develops can vary significantly depending on the individual.
Stage 2: Claudication
Most people with PAD will not experience any symptoms but for those who do, this is normally the first. Also called “intermittent claudication”, it is fatigue, discomfort or pain in the muscles of the legs.
It will normally occur when walking. Specifically, the pain often occurs in the calves, upper legs, buttocks or feet. The pain is a signal that the muscles are suffering from lack of oxygen. Walking puts them under increased strain, so that more oxygen and more efficient blood circulation is required. However, this is not possible due to reduced blood flow in the narrowed arteries.
Stage 3: Advanced PAD: Pain at rest
Failure to stop the progression of PAD leads to the increasing deterioration of the blood circulation. In addition to pain when walking, you may experience pain even at rest, particularly at night if your legs are raised.
Stage 4: Tissue damage
Without proper blood flow, wounds cannot heal. Even a small cut will have difficulty healing. This could lead to infections and permanent tissue damage. In the worst cases, amputation may even be necessary if adequate blood flow cannot be restored. Please note however that amputation occurs in only a very small minority of patients.