Peripheral vascular disease

Peripheral vascular disease is an important risk factor for diabetic foot disease which still leads to the loss of 5,000 lower limbs every year in the UK. It should be detected early by examining pedal pulses at the annual review and managed actively with lipid modification, smoking cessation, antiplatelet agents and surgical referral for revascularisation.

Prevention

What are the main strategies for prevention of peripheral vascular disease?

The prevention of peripheral vascular disease is multifactorial and should include smoking cessation, blood pressure control, modification of lipids, good glycaemic control and lifestyle factors (diet, weight, exercise).

Smoking cessation

Smoking is arguably the single most important macrovascular risk factor. Patients who smoke should be encouraged and helped to stop smoking at all costs.

They are much more likely to succeed if it is done with some sort of professional support and appropriate referral should be made. Smoking cessation clinics will not only provide one to one or group support but will also be expert in the full range of smoking cessation drugs (nicotine replacement products, bupropion and varenicline).

Blood pressure control

In the 1990s, the UKPDS study showed that effective antihypertensive therapy is as important as good glycaemic control in reducing macrovascular risk in T2DM. Blood pressure targets of 140/80 in the absence of microalbuminuria and 130/80 in the presence of microalbuminuria are currently recommended in the UK for T2DM, similar targets for those with T1DM would not be unreasonable.

Overzealous BP reduction carries risks of its own and the recent publication of ACCORD-BP highlighted the risks of attempting to reduce BP to less than 120/80 mm Hg in an elderly population with T2DM at increased risk of cardiovascular disease.

Lipid modification

The precise details of treatment targets are still hotly debated topics. However, there is some agreement that most people with T2DM and T1DM over the age of 40 should probably be on a statin. Some argue that total cholesterol target should be 4 mmol/L and LDL cholesterol target should be 2 mmol/L, however, these targets are not universally accepted.

There is also some debate about the role of 'residual dyslipidaemia' in patients already on statin therapy who are not at target and whether or not these patients should receive additional fibrate therapy. There are many diabetes specialists who would actively consider fibrate therapy in a patient on maximal tolerated statin doses who still has a total cholesterol significantly above 4 mmol/L and/or a low (<1mmol/L) HDL cholesterol +/- elevated fasting triglycerides.

A convenient fibrate is fenofibrate 200 mcg od and the safety of this in combination with a statin is actually very favorable. 

Aspirin

Aspirin should probably not be used for primary prevention of macrovascular disease in diabetes except in obviously high-risk individuals with diabetes (e.g. smokers, marked dyslipidaemia).

Glycaemic control

Good glycaemic control is an important factor in helping to prevent peripheral arterial disease but it is only part of the strategy.

Smoking cessation, lipid modifications and blood pressure control are arguably as important components of the overall strategy.

Lifestyle

Weight control, eating a diet low in saturated animal fats and exercising regularly are all effective ways to reduce the risk of macrovascular disease.

Management

Secondary prevention measures

It is essential once a patient has presented with their first manifestation of arterial disease of any description that all secondary prevention measures are vigorously pursued (smoking, cholesterol, blood pressure, aspirin and glycaemia).

Angioplasty/surgery

A vascular surgeon experienced in the management of peripheral arterial disease in diabetes should assess the patient.

Peripheral arterial disease in diabetes tends to be different from that in the non-diabetic patient with a preponderance of distal and small vessel disease. The relative merits of angioplasty and bypass surgery should be carefully considered and discussed with the patient.

There is some evidence to suggest that patients who have been managed with a proactive policy of revascularisation are less likely to undergo amputation.

Amputation

Sometimes amputation will become unavoidable. The primary goal of amputation should be preservation of as much function as possible. Thus, the usual aim is to minimise surgery to distal (digital or forefoot) amputation as far as possible.

Much better functional results are achieved when this surgery is performed be a surgeon with a specialist interest in such work as more consideration will be given to the biomechanics of the residual foot.

When a major (below, through or above knee) amputation is required, the patient will first be assessed by a rehabilitation physician and the precise level of the surgery and the post operative plan for prosthetic limb fitting and rehabilitation are considered in advance.

On occasion, a potential major amputation can be down-graded to a minor amputation by aggressive revascularisation even if there is no prospect of completely saving the foot. Multi-disciplinary team working around such decision making should be the norm to optimise outcomes.

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