[Extracardiac manifestation of elevated lipoprotein(a) levels--cumulative incidence of peripheral arterial disease and stenosis of the carotid artery]

The association of lipoprotein(a) and apolipoprotein(a) phenotypes with peripheral artery disease

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.

The Association of Lipoprotein(a), Apolipoprotein(a) Phenotypes and Autoantibodies to Lipoprotein(a) With Lower Extremity Artery Disease

AIM

Lipoprotein(a) [Lp(a)] and low molecular weight (LMW) apolipoprotein(a) [apo(a)] phenotype are risk factors of сoronary heart disease and stroke. Data about the role of Lp(a) and phenotypes apo(a) in the development of lower extremity artery disease (LEAD) is scarce. The aim of our study was to assess the association of Lp(a), apo(a) phenotypes and autoantibodies to apolipoprotein B100 (apoB100) lipoproteins with LEAD.

MATERIALS AND METHODS

The study included 622 patients (386 male and 236 female, average age 61±12 years), examined in the Department of Atherosclerosis of National Medical Research Center of Cardiology. Patients were divided into 2 groups: the main group included 284 patients with LEAD, 338 patients without significant atherosclerosis of coronary, carotid and lower limbs arteries formed the control group. LEAD was diagnosed as atherosclerotic lesions with at least one stenosis of low limb artery ≥50 % and ankle-brachial index ≤0.9. The concentration of Lp(a), lipids was measured in blood serum of all the patients, level of autoantibodies to apoB100 lipoproteins was measured in 247 patients, and apo(a) phenotypes were determined in 389 patients.

RESULTS

Patients with LEAD were older, were more frequently male, and had a greater prevalence of risk factors including hypertension, type 2 diabetes, smoking than the control group patients (p&lt;0.001 in all the cases). The level of Lp(a) was significantly higher in the main group compared to control group: 35 [14; 67] mg / dl vs. 14 [5; 32] mg / dl, p&lt;0,001. ROC analysis demonstrated that the level of Lp(a) ≥26 mg / dl was associated with LEAD (sensitivity 61 %, specificity 70 %). The prevalence of Lp(a) ≥26 mg / dl and LMW apo(a) phenotype were higher in the main group in comparison with the control group: 61 % vs. 30 % and 48 % vs. 26 % respectively (p&lt;0.001 in the both cases). The odds ratio of LEAD in the presence of Lp(a) ≥26 mg / dl was 3.7 (95 % confidence interval (CI), 2.6-5.1, p&lt;0.001) and in the presence of LMW apo(a) phenotype was 2.6 (95 % CI, 1.7-4.0, p&lt;0.001). In logistic regression analysis adjusted for age, sex, hypertension, smoking, diabetes, both Lp(a) and LMW apo(a) phenotype were independent predictors of LEAD when included separately. The level of IgM autoantibodies to Lp(a) was significantly higher in the control group compared to the patients with LEAD (p=0.01). Concentration of IgG autoantobodies to Lp(a) and LDL in the plasma did not differ essentially in the both groups.

CONCLUSION

The level of Lp(a) ≥26 mg / dl and LMW apo(a) phenotype are independent predictors of LEAD, whereas the contribution of autoantobodies to Lp(a) in LEAD development is controversial.

Lack of Correlation of Carotid Intima-Media Index and Peripheral Artery Disease

INTRODUCTION

Increased carotid intima-media thickness (IMT) measurement is usually seen as a surrogate marker of peripheral artery disease (PAD) but there is scarce cumulated evidence to support this view.

AIM

To evaluate prevalence of increased IMT among patients with symptomatic PAD as well as the frequency of some cardiovascular risk factors in these patients.

METHODS

They were recruited 230 patients with diagnosis of medium peripheral artery disease in the Vascular Surgery Service outpatient's office. Serum cystatin C, homocysteine, and lipoprotein (a) were measured. GFR was estimated using the CKD-EPI equation and the Larsson one from cystatin C.

RESULTS

The global prevalence of increased IMT was 16.5% (n = 38, 95% CI 12.3-21.9). In all the frequency of hyperlipoproteinemia (a) was 34.2% (95% CI 28.4-40.5%). The global prevalence of hyperhomocysteinemia was 61.5% (95% CI 54.6-68.1%) and the proportion of patients with high cystatin C levels was 38.5% (95% CI 32.1-42.5). The prevalence of stage III chronic kidney disease or higher by CKD-EPI formula was much lesser (13.6%, 95% CI 9.7-18.7) as was the frequency obtained by the Larsson equation (28.7%, 95% CI 23.2-34.9). No differences were found between groups.

CONCLUSIONS

Increased IMT is not common among PAD patients. Hyperlipoproteinemia (a) and hyperhomocysteinemia are very frequent in these patients. High serum cystatin levels are also very prevalent but reduced GFR is not so frequent. There were no differences in the prevalence of the studied cardiovascular risk factors between those patients with increased IMT and those ones with normal IMT.

Incidence of elevated lipoprotein (a) levels in a large cohort of patients with cardiovascular disease

Background

Recently it has been demonstrated that elevated lipoprotein (a) (LPA) levels are associated with an increased risk of cardiovascular disease across multiple ethnic groups. However, there is only scanty data about the incidence of elevated LPA levels in different patient cohorts. As a consequence, we aimed to examine whether patients with elevated LPA levels might be seen more often in a cardiovascular center in comparison to the general population.

Methods

We reviewed LPA concentrations of 52,898 consecutive patients who were admitted to our hospital between January 2004 and December 2014. We subdivided them into different groups according to their LPA levels. Data was compared to available information in medical literature.

Results

26.4% of the patients had LPA levels >30 mg/dl which is in line with the data from literature. Mean level of LPA concentration in our study was twice as high in comparison to the general population (25.8% vs. 13.3%). 4.6% had LPA levels >98 mg/dl (general population <0.3%).

Conclusion

In patients admitted to a cardiovascular center the proportion of LPA >30 mg/dl is comparable to the general population but mean levels over all are twice as high and the proportion of patients with LPA levels of >98 mg/dl is extremely higher.