Aim: Lipoprotein(a) [Lp(a)] is an independent risk factor of coronary heart disease (CHD) and myocardial infarction. Data about the role of Lp(a) in the development of peripheral artery disease (PAD) is controversial and uncertain. The aim of the study was to evaluate the association between Lp(a), apolipoprotein(a) [apo(a)] phenotypes and PAD.
Materials and methods: The study included 998 patients (707 male and 291 female, average age 60±12). The patients were divided into 4 groups depending on the presence or absence PAD and CHD: group I (n=188, PAD+CHD+), group II (n=78, PAD+CHD-), group III (n=407, PAD-CHD+), group IV (n=325, PAD-CHD-).
Results: The level of Lp(a) was significantly higher in groups I, II, III in comparison with patients of control group (group IV): 34 [15; 80], 30 [10; 49], 22 [8; 60] mg/dl vs. 15 [6; 35] mg/dl respectively, p<0.01 in all cases. Lp(a) level was higher in the group I than in the other groups (p<0.05). The prevalence of elevated Lp(a) level (≥ 30 mg/dl) was significantly higher in groups I, II, III than in control group: 54%, 50%, 43% respectively vs. 30%, p<0.01 in all cases. The prevalence of Lp(a) ≥ 30 mg/dl was more frequent in the group with PAD and CHD than in the group with CHD and without PAD (p=0.02). The odds ratio (OR) of PAD in the presence of elevated Lp(a) level was 1.9 (95%CI, 1.4-2.5, p<0.01). Low molecular weight (LMW) apo(a) phenotype was met more frequently in groups I, II, III compared to group IV: 46%, 56%, 52% respectively vs. 28%, p<0.01. LMW apo(a) in the patients without CHD was associated with PAD (OR 3.3; 95% CI, 1.6-6.8, p<0.01), and there was no association with the patients with CHD. In logistic regression analysis adjusted for age, sex, hypertension, obesity, smoking, diabetes, LDL-C, Lp(a) and LMW apo(a) phenotype were independent predictors of PAD when included separately.
Conclusion: Elevated level of Lp(a) and LMW apo(a) phenotype are independent risk factors of PAD. The level of Lp(a) in the patients with PAD and CHD was higher than in the case of isolated lesion of each vascular pool. Higher level of Lp(a) is associated with more severe atherosclerosis involving more than one vascular pools.
Keywords: apolipoprotein(a) phenotypes; atherosclerosis; atherosclerosis of lower limbs arteries; lipoprotein(a); peripheral artery disease.