Atherogenic lipoprotein phenotype and LDL size and subclasses in patients with peripheral arterial disease.

The type of dyslipidemia in patients with peripheral arterial disease (PAD) is still ill defined. PAD patients often show elevated triglycerides and reduced HDL-cholesterol, two lipid abnormalities usually accompanied by decreased LDL size in the "atherogenic lipoprotein phenotype" (ALP). We investigated (1) whether PAD patients have lower LDL size, (2) altered LDL subclass distribution and (3) the prevalence of ALP. We measured plasma lipids and LDL size and subclasses by gradient gel electrophoresis in 31 adults with intermittent claudication and 31 age-BMI-matched controls. Patients had higher prevalence of hypertension (p=.0132), smoking (p<.0020) and diabetes (p=.0024), with lower HDL-cholesterol (p<.0001) and increased triglycerides (p=.0057); LDL size was smaller (p<.0001), with decreased larger subclasses (LDL-I, p<.0001; LDL-IIA, p=.0068) and increased smaller particles (LDL-IIIA, p<.0001; LDL-IIIB, p=.0013; LDL-IVA, p=.0029; LDL-IVB, p<.0001). The presence of PAD was independently associated with smoking (OR 7.2, p=.0099), hypertension (OR 6.5, p=.0362), diabetes (OR 5.5, p=.0450) and elevated small, dense LDL (OR 6.7, p=.0497). The concomitant presence of high triglycerides, low HDL-cholesterol and elevated small, dense LDL in patients was 26% (versus 0% controls, p=.0024). ALP seems to characterize PAD dyslipidemia, but prospective studies are needed to test whether this lipoprotein phenotype may represent a risk factor too.