PERIPHERAL ARTERIAL DISEASE (PAD)
Part 1: Epidemiology, Natural History, Risk Factors and Prevention.
Definition
of Peripheral Arterial Disease (PAD)
Intermittent
claudication (IC) is diagnosed by a history of leg pain on excersise that is
relieved by rest. In men over 60 years the prevalence of IC is 3 - 6%. The
prevalence of asymptomatic peripheral arterial disease (PAD) ranges from 0.9 -
22%.
Risk
factors for developing IC
-
Diabetes
mellitus. IC is twice as common among diabetics.
-
Smoking.
Smokers have IC three times more commonly than non-smokers. PAD occurs a
decade earlier in smokers. Its severity increases with the number of cigarettes
smoked. With cessation of smoking comes a rapid decline in the incidence
of IC and the risk for ex-smokers one year after giving up is the same
as for non-smokers.
-
Hypertension.
This causes a 2.5 fold risk increase for men and 3.9 fold increase risk
for women for PAD.
-
Hyperlipidaemia.
A fasting cholesterol > 7 mmol/l
has twice the incidence of IC. The ratio of total to HDL cholesterol is
the best predictor of this. Smoking enhances the effect of raised
cholesterol.
-
Hyperhomocysteinamia.
Its incidence is as high as 60% in the vascular population vs. 1% in the
general population and can be detected in 28 - 30% of patients with
premature PAD.
-
Genetic
risk. Although a link has been found in coronary artery
disease (CAD), this has not been found to be a risk factor in PAD.
-
Exercise.
Regular exercise is protective against PAD.
Co-existing Vascular Disease.
PAD,
CAD and cerebrovascular disease (CVD) frequently co-exist. CAD is present in
40 - 60% of patients with PAD. In fact, in the well known Cleveland Clinic
Study (1978) where all patients with PAD had a coronary angiography, the
prevalence was as high as 90%.
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