Peripheral artery occlusive disease

In medicine (vascular surgery), peripheral artery occlusive disease (PAOD, also known as peripheral vascular disease or PVD) is a collator for all disease caused by the obstruction of large peripheral arteries, which can result from atherosclerosis, inflammatory processes leading to stenosis, an embolism or thrombus formation. It causes either acute or chronic ischemia.

Classification

Peripheral artery occlusive disease is commonly divided in the Fontaine stages:

I: mild pain on walking ("claudication")
II: severe pain on walking relatively shorter distances (intermittent claudication)
III: pain while resting
IV: loss of sensation to the lower part of the extremity
V: tissue loss (gangrene)

Causes

All causes of atherosclerosis are also causes of PAOD. There is, however, a strong preponderance of diabetic people who smoke. A known diabetic who smokes runs an approximately 30% risk of amputation within 5 years.

Diagnosis

Upon suspicion of PAOD, the first-line test is the ankle brachial pressure index (ABPI/ABI) which is a measure of the fall in blood pressure in the arteries supplying the legs. A reduced ABPI (less than 0.9) is consistent with PAOD. Values of ABPI below 0.8 indicate moderate disease and below 0.5 severe disease.

If ABI's are abnormal the next step is generally a lower limb doppler ultrasound examination to look at site and extent of atherosclerosis at the femoral artery. Other imaging can be performed by angiography, where a catheter is inserted into the femoral artery and selectively guided to the artery in question and then used to inject radiodense contrast agent whilst an X-ray is taken. Any stenosis of the arteries can be identified and treated at the same time by balloon angioplasty if the stenosis is over a short segment (<3cm). However if the artery is occluded or there is diffuse disease present, then arterial bypass surgery may be required. Modern multislice computerized tomography (CT) scanners provide direct imaging of the arterial system as an alternative to angiography. CT provides complete evaluation of the aorta and lower limb arteries without the need for an angiogram's arterial injection of contrast agent.

Therapy

Dependent on the severity of the disease, the following steps can be taken:

Conservative measures include Smoking cessation (cigarettes promote PAOD and are a risk factor for cardiovascular disease). Regular exercise for those with claudication helps open up alternative small vessels (collateral flow) and the limitation in walking often improves. Medication with aspirin,clopidogrel and statins, which reduce clot formation and cholesterol levels, respectively can help with disease progression and address the other cardiovascular risks that the patient is likely to have.
Angioplasty (PTA or percutaneous transluminal angioplasty) can be done on solitary lesions in large arteries, such as the femoral artery.
Occasionally, bypass grafting is needed to circumvent a seriously stenosed area of the arterial vasculature. Generally, the saphenous vein is used, although artificial (Gore-Tex) material is often used for large tracts when the veins are of lesser quality.
Rarely, sympathectomy is used - removing the nerves that make arteries contract, effectively leading to vasodilatation.
When gangrene of toes has set in, amputation is often a last resort to stop infected dying tissues from causing septicemia.

Arterial thrombosis or embolism has a dismal prognosis, but is occasionally treated successfully with thrombolysis.

Associations

Many PAOD patients also have angina pectoris or have had myocardial infarction. There is also an increased risk for stroke.

External links

Cardiovascular diseases | Vascular surgery | Angiology

Arterielle Verschlusskrankheit | 閉塞性動脈硬化症 | Etalagebenen | Doença arterial periférica