Peripheral vascular disease

Published on 10/04/2015 by admin

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Last modified 10/04/2015

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CHAPTER 15 Peripheral vascular disease

Arterial

Examination

The patient’s limb should be examined in a warm room.

Arterial occlusive disease

Acute arterial occlusion

This is defined as a deterioration in the blood supply of the leg that leads to rest pain or signs of severe ischaemia of less than 2 weeks’ duration. This may range from a patient without PVD who has an embolic occlusion and presents with a dramatically ischaemic limb to a patient with chronic PVD who develops severe new onset rest pain.

Chronic arterial occlusion

Lower limb (aorto-ilio-femoral disease)

Treatment

Medical

Mild to moderate claudication that is not disabling does not require surgical treatment. Advice is given to patients to lose weight, stop smoking, exercise regularly within their claudication distance. Advice is also given on foot care, particularly chiropody. Antiplatelet agents should be given, usually aspirin, but in patients who will not tolerate aspirin, an alternative antiplatelet agent should be prescribed, e.g. clopidogrel. Correct any cholesterol or triglyceride abnormality with a statin. There is clear evidence that cardiac events can be reduced by up to one-third by reducing low density lipoproteins/cholesterol by one-third, regardless of the baseline cholesterol, down to a total cholesterol of 3.5 mmol/L by use of a statin. Control hypertension. Nicotine patches to help stop smoking. Drugs such as naftidrofuryl and cilostazol have been used and may increase pain-free walking distance. Infusions of Iloprost (a prostacyclin analogue) are occasionally used in critical ischaemia with no hope of reconstruction but are rarely helpful. Regular patient follow-up is required. Patients should be encouraged to seek medical advice if claudication suddenly deteriorates or rest pain develops.

Chemical lumbar sympathectomy with injection of phenol under radiological guidance can occasionally be used in patients with unreconstructable disease in an attempt to control pain.

Cerebrovascular disease

Some 80% of strokes are ischaemic and 20% are haemorrhagic. Atherosclerosis is the commonest cause and usually affects the internal carotid artery just distal to the common carotid bifurcation. Disruption of a plaque at this point can lead to thrombus formation and secondary embolism, leading to a stroke or TIA. A stroke is defined as a focal neurological deficit of >24 h of presumed vascular origin. A TIA has a similar definition but lasts <24 h. In practice, TIAs often last <30 min.

Treatment

Management depends on two factors, i.e. degree of stenosis and whether it is symptomatic or asymptomatic. Patients with a carotid stenosis of <50%, whether symptomatic or not, should be managed medically. Patients with a symptomatic stenosis >50% are generally best treated by carotid endarterectomy. Asymptomatic patients with stenosis >60% are best treated by carotid endarterectomy. Another group of asymptomatic patients that often require intervention are patients undergoing coronary artery bypass grafting. In these patients, a high grade stenosis (i.e. >90%) or a combined stenosis (right and left carotid) >150% are indications for treatment.

Renovascular disease

Hypertension may be caused be renal hypoperfusion with release of renin from juxtaglomerular cells with activation of angiotensin. The most common causes are arteriosclerosis and fibromuscular dysplasia of the renal arteries. Arteriosclerosis usually involves the origin of the artery and occurs in the older patient. Fibromuscular dysplasia affects the middle to distal part of the artery and usually occurs in the younger patient. Renal artery stenosis has been shown to increase 5-year mortality in patients with peripheral vascular disease and in coronary artery disease it has been shown to double the risk of death, despite coronary revascularization.

Renal artery stenosis is an important, and potentially correctable, cause of renal failure in the older patient. The diagnosis of renal artery stenosis is frequently made following a deterioration of renal function in patients commenced on angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor (AR) blockers.