Intermediate-density lipoprotein as an independent risk factor for aortic atherosclerosis in hemodialysis patients.

Patients with chronic renal failure often show accumulation of intermediate-density lipoprotein (IDL). Because recent studies have emphasized the atherogenicity of IDL in the general population, we evaluated the relationship between this lipoprotein and aortic atherosclerosis in uremic patients treated with hemodialysis. Aortic pulse wave velocity (PWV) was measured as a noninvasive index of sclerotic change of aorta in 205 hemodialysis patients and 184 age- and gender-matched healthy subjects. Fasting plasma lipoproteins were fractionated by ultracentrifugation into very low-density lipoprotein (VLDL), IDL, LDL, and HDL. Plasma lipoprotein (a) (Lp(a)) was measured by a latex immunoturbidimetric assay. Aortic PWV was significantly higher in the hemodialysis patients than in the control subjects. The hemodialysis group showed a significant increase in VLDL and IDL cholesterol, whereas their LDL and HDL cholesterol were lower than the control levels. Lp(a) levels did not differ between the two groups. In the hemodialysis population, VLDL, IDL, and LDL cholesterol correlated positively with aortic PWV adjusted for age, gender, smoking, and BP, whereas Lp(a) did not. Multiple regression analyses indicated that plasma triglycerides, independent of HDL cholesterol, had a significant association with aortic PWV in the hemodialysis patients but not in the control subjects. Further analyses revealed that aortic PWV in the hemodialysis patients had a significant and independent association with IDL cholesterol, whereas aortic PWV in the control subjects had significant and independent associations with HDL cholesterol and Lp(a). These results demonstrate that IDL is the lipoprotein fraction most closely associated with aortic PWV in the hemodialysis patients.