The influence of smoking cessation and hypertriglyceridaemia on the progression of peripheral arterial disease and the onset of critical ischaemia.

Abstract

To investigate whether smoking and other cardiovascular risk factors were associated with deterioration of ankle/brachial pressure index or onset of critical ischaemia in patients with mild to moderate intermittent claudication. Longitudinal study in a London teaching hospital. 415 consecutive smokers, with symptoms of intermittent claudication and an ankle/brachial pressure index of <0.9, referred for a surgical opinion between April 1985 and December 1990, who were not considered for an immediate surgical procedure. Reduction in ankle/brachial pressure index of >0.14, onset of critical limb ischaemia. After one year of follow up 183 patients (44%) had stopped smoking (as evaluated by biochemical markers). With longer follow up only 110 patients (27%) had maintained smoking cessation. There were no differences in age, sex, and previous tobacco exposure between stoppers and smokers, but the proportion of diabetics among stoppers (20%) was greater than among those who continued smoking (10%) [p=0.01]. The annual rate of deterioration of ABPI was 21, 16 and 17% respectively in the first, second and third year of follow-up and the onset of critical ischaemia was observed in 52 patients (12.5%) during the period of follow-up. In univariate analyses, continued smoking, diabetes and presence of ischaemic heart disease were not associated with an increased risk of deterioration of ABPI, but hypertriglyceridaemia (> or = 2.2 mmol/l) was, [relative risk 1.7(95% CI 1.21-2.37), p=0.003], and patients having systolic blood pressure in the middle tertile (153-170 mmHg had a reduced risk of deterioration of ABPI, p=0.026. Hypertriglyceridaemia (> or = 2.2mmol/l) was the only independent factor associated with deterioration of ABPI in multivariate analysis [relative risk 1.8(95% CI:1.23-2.59), p=0.003] and also was associated with a relative risk of onset of critical ischaemia of 1.9 [(95% CI: 1.08-2.87), p=0.035], compared with triglyceride levels of <2.2mmol/l. For those with mild to moderate claudication, the lack of immediate benefit from cessation of smoking appears to be associated with a gradual return to smoking. Hypertriglyceridaemia was identified as the most important independent factor associated with the progression of peripheral arterial disease and onset of critical ischaemia.