Peripheral arterial disease

Description

Peripheral arterial disease (PAD) is generally a disorder of the arteries of the legs - and more rarely the arms - in which there is hardening of the arteries (atherosclerosis), causing severe narrowing or even complete blockage of the blood vessels and thus reduced blood flow to the extremities. PAD of the legs is divided into three types depending on its location: pelvis (iliac arteries), thigh (femoral artery) and lower leg (fibular and foot arteries). Another form of PAD known as Leriche's syndrome (aortoiliac occlusive disease) occurs when the infrarenal abdominal artery is blocked, leading to circulatory disorders of both legs, with pain in the buttocks and legs. In men there can also be erectile dysfunction. PAD is a relatively common disorder. Its reported prevalence in Germany is up to 10% of the population over 50 years old - but the disease is symptomatic in only a third of all cases. Men are affected about four times more often than women.

Symptoms

PAD is divided (according to Fontaine) into four stages, depending on the type and severity of symptoms. Stage I: No complaints, and one's walking distance is therefore not restricted. Stage II: The muscles located behind the constriction no longer receive enough oxygen during exercise, causing intermittent claudication (pain in the affected leg). This is sometimes called "window display disease" because the intermittent pain forces one to cease physical activity and stand still after walking a certain distance. Thus this stage is subdivided further depending on the walkable distance. Stage IIa: The painless walkable distance is more than 200 meters. Stage IIb: The painless walkable distance is less than 200 meters. Stage III: Pain even when at rest. Stage IV: Tissue destruction (necrosis) with occurrence of abscesses and leg ulcers due to lack of oxygen supply.

In addition to pain there are other symptoms typical of circulatory disorders of the extremities: the affected limb is cold and pale behind the constriction (stenosis), and during exercise there is muscle weakness and the pulse is absent. Ulcers and wounds no longer heal due to the reduced oxygen supply.

Causes and Risks

The cause of PAD is in most cases atherosclerosis. Only occasionally are injuries, inflammatory disease, embolism, or inflammation of the large blood vessels the cause of circulatory disorders. Some of the main risk factors for atherosclerosis and thus for PAD are smoking, diabetes mellitus, high blood pressure (arterial hypertension) and dyslipidemia.

Other risk factors for atherosclerosis include: gender (men are more frequently affected than women), advancing age, genetic predisposition, unhealthy diet (e.g. too much fat and meat, too few fruits and vegetables), excess weight (obesity) and lack of exercise.

Examination and Diagnosis

To confirm the diagnosis when PAD is suspected, the doctor will perform a series of examinations. Physical examination: skin color, trophic disorders, pulse, skin temperature, blood flow noises, checking sensitivity and motor function. Clinical performance tests: ergometry to determine the distance walked on a treadmill, Ratschow's test, Allen test, etc. Doppler sonography and oscillography  are also used. Diagnostic imaging: color duplex ultrasound, digital subtraction angiography (DSA), CT angiography (CTA), magnetic resonance angiography (MRA). Laboratory tests: creatine kinase (CK), myoglobin, C-reactive protein (CRP).

Treatment

Treatment of PAD should be carried out according to the disease stages. In Stage I, the priority is a conservative adjustment of cardiovascular risk factors. The success of the treatment depends largely on the patient's cooperation. The more actively that patients combat the risk factors (e.g. giving up smoking, controlling blood pressure, etc.), the better they can stop the progression of PAD and avoid complications such as heart attack or stroke. In Stage II, in addition to adjustment of risk factors, come drug therapy and intensified walking and vascular training. Both directly vasoactive substances such as cilostazol as well as antiplatelet drugs (e.g. clopidogrel) are employed. But also crucial is movement therapy, which in particular stimulates the development of collateral circulation and thus directly leads to improvement of the blood supply to the affected limb. From Stage II to IV, in addition to drug therapy, revascularization measures are also available. These can take place either through surgery or by means of a catheter procedure. Here, the narrowed or blocked vessel section will be reopened by means of a catheter and provided with a vascular support (stent) so that blood flow is restored. In surgical therapy a bypass method is employed. In Stage IV, if for example a revascularization procedure is no longer possible because of massive tissue damage, then amputation is often the final life-saving procedure.

Course and Prognosis

The course of PAD depends on many factors, and in particular on how well the underlying arteriosclerosis is stopped. The patient influences to a great extent which course PAD takes, by consistently working against the risk factors of atherosclerosis. This includes in particular giving up smoking, and stopping potential diabetes disease with medication. Although atherosclerosis cannot be cured, the process can however be slowed and perhaps even stopped.

Miscellaneous/Other Comments

PAD is often associated with other (cardio-)vascular diseases such as coronary heart disease or cerebral vascular disease. In this context a patient known to have PAD should be queried about any heart and central nervous system complaints.