Cardiovascular disease risk associated with elevated lipoprotein(a) attenuates at low low-density lipoprotein cholesterol levels in a primary prevention setting.

Aims: Lipoprotein(a) (Lp(a)) elevation is a causal risk factor for cardiovascular disease (CVD). It has however been suggested that elevated Lp(a) causes CVD mainly in individuals with high low-density lipoprotein cholesterol (LDL-C) levels. We hypothesized that the risk associated with high Lp(a) levels would largely be attenuated at low LDL-C levels. Methods and results: In 16 654 individuals from the EPIC-Norfolk prospective population study, and in 9448 individuals from the Copenhagen City Heart Study (CCHS) parallel statistical analyses were performed. Individuals were categorized according to their Lp(a) and LDL-C levels. Cut-offs were set at the 80th cohort percentile for Lp(a). Low-density lipoprotein cholesterol cut-offs were set at 2.5, 3.5, 4.5, and 5.5 mmol/L. Low-density lipoprotein cholesterol levels in the primary analyses were corrected for Lp(a)-derived LDL-C (LDL-Ccorr). Multivariable-adjusted hazard ratios were calculated for each category. The category with LDL-Ccorr <2.5 mmol/L and Lp(a) <80th cohort percentile was used as reference category. In the EPIC-Norfolk and CCHS cohorts, individuals with an Lp(a) ≥80th percentile were at increased CVD risk compared with those with Lp(a) <80th percentile for any LDL-Ccorr levels ≥2.5 mmol/L. In contrast, for LDL-Ccorr <2.5 mmol/L, the risk associated with elevated Lp(a) attenuated. However, there was no interaction between LDL-Ccorr and Lp(a) levels on CVD risk in either cohort. Conclusion: Lipoprotein(a) and LDL-C are independently associated with CVD risk. At LDL-C levels below <2.5 mmol/L, the risk associated with elevated Lp(a) attenuates in a primary prevention setting.

Carriers of the PCSK9 R46L Variant Are Characterized by an Antiatherogenic Lipoprotein Profile Assessed by Nuclear Magnetic Resonance Spectroscopy-Brief Report.

OBJECTIVE: Carriers of the PCSK9 (proprotein convertase subtilisin/kexin 9) R46L genetic variant (rs11591147) are characterized by low levels of low-density lipoprotein cholesterol and a decreased risk of cardiovascular disease. We studied the impact of the R46L variant on lipoprotein size and composition. APPROACH AND RESULTS: Lipoprotein size and composition were measured by nuclear magnetic resonance spectroscopy in 2373 participants of the EPIC (European Prospective Investigation into Cancer and Nutrition)-Norfolk study. After adjusting for age, sex, and cardiovascular disease status, carriers of the R46L variant (n=77) were characterized by lower concentrations of very low-density lipoprotein particles (85.8±26.2 versus 99.0±33.3 nmol/L; P<0.001), low-density lipoprotein particles (1479.7±396.8 versus 1662.9±458.3 nmol/L; P<0.001), and lipoprotein(a) (11.1 [7.2-28.6] versus 12.4 [6.7-29.1] mg/dL; P<0.001) compared with noncarriers. Total high-density lipoprotein particle and very low-density lipoprotein, low-density lipoprotein, and high-density lipoprotein particle sizes were comparable in carriers and noncarriers. Carriers were characterized by lower secretory phospholipase A2 (4.2±0.9 versus 4.6±1.3 nmol/mL/min; P=0.004) and lipoprotein-associated phospholipase A2 activity (47.5±14.1 versus 52.4±16.2 nmol/mL/min; P=0.02) compared with noncarriers. CONCLUSIONS: Results of this study suggest that carriers of the PCSK9 R46L genetic variant have lower very low-density lipoprotein and low-density lipoprotein particle concentrations, lower lipoprotein(a) levels, and lower secretory phospholipase A2 and lipoprotein-associated phospholipase A2 activity compared with noncarriers.

Population and assay thresholds for the predictive value of lipoprotein (a) for coronary artery disease: the EPIC-Norfolk Prospective Population Study.

Variable agreement exists between different lipoprotein (a) [Lp(a)] measurement methods, but their clinical relevance remains unclear. The predictive value of Lp(a) measured by two different assays [Randox and University of California, San Diego (UCSD)] was determined in 623 coronary artery disease (CAD) cases and 948 controls in a case-control study within the EPIC-Norfolk Prospective Population Study. Participants were divided into sex-specific quintiles, and by Lp(a) <50 versus ∼50 mg/dl, which represents the 80th percentile in northern European subjects. Randox and UCSD Lp(a) levels were strongly correlated; Spearman's correlation coefficients for men, women, and sexes combined were 0.905, 0.915, and 0.909, respectively (P< 0.001 for each). The >80th percentile cutoff values, however, were 36 mg/dl and 24 mg/dl for the Randox and UCSD assays, respectively. Despite this, Lp(a) levels were significantly associated with CAD risk, with odds ratios of 2.18 (1.58-3.01) and 2.35 (1.70-3.26) for people in the top versus bottom Lp(a) quintile for the Randox and UCSD assays, respectively. This study demonstrates that CAD risk is present at lower Lp(a) levels than the currently suggested optimal Lp(a) level of <50 mg/dl. Appropriate thresholds may need to be population and assay specific until Lp(a) assays are standardized and Lp(a) thresholds are evaluated broadly across all populations at risk for CVD and aortic stenosis.

Non-high-density lipoprotein cholesterol: current status as cardiovascular marker.

PURPOSE OF REVIEW: In this review, we summarize the evidence with regard to the rationale of using nonhigh density lipoprotein cholesterol (non-HDL-C) as a cardiovascular disease (CVD) risk factor, in relation to low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB). RECENT FINDINGS: In the 2015 National Lipid Association Annual Summary non-HDL-C is considered a coprimary target, apart from LDL-C. The other data published in the last 18 months about non-HDL-C support all the previous published data. There are no recent findings, which we deem to cause a change of the current opinion about non-HDL-C as a predictor for CVD. SUMMARY: The existing evidence supports the claim that non-HDL-C is superior to LDL-C in CVD risk estimation.

Lipoprotein(a) is robustly associated with aortic valve calcium.

OBJECTIVES: To investigate the prevalence and quantity of aortic valve calcium (AVC) in two large cohorts, stratified according to age and lipoprotein(a) (Lp(a)), and to assess the association between Lp(a) and AVC. METHODS: We included 2412 participants from the population-based Rotterdam Study (52% women, mean age=69.6±6.3 years) and 859 apparently healthy individuals from the Amsterdam University Medical Centers (UMC) outpatient clinic (57% women, mean age=45.9±11.6 years). All individuals underwent blood sampling to determine Lp(a) concentration and non-enhanced cardiac CT to assess AVC. Logistic and linear regression analyses were performed to investigate the associations of Lp(a) with the presence and amount of AVC. RESULTS: The prevalence of AVC was 33.1% in the Rotterdam Study and 5.4% in the Amsterdam UMC cohort. Higher Lp(a) concentrations were independently associated with presence of AVC in both cohorts (OR per 50 mg/dL increase in Lp(a): 1.54 (95% CI 1.36 to 1.75) in the Rotterdam Study cohort and 2.02 (95% CI 1.19 to 3.44) in the Amsterdam UMC cohort). In the Rotterdam Study cohort, higher Lp(a) concentrations were also associated with increase in aortic valve Agatston score (ß 0.19, 95% CI 0.06 to 0.32 per 50 mg/dL increase). CONCLUSIONS: Lp(a) is robustly associated with presence of AVC in a wide age range of individuals. These results provide further rationale to assess the effect of Lp(a) lowering interventions in individuals with early AVC to prevent end-stage aortic valve stenosis.

A 3-SNP gene risk score and a metabolic risk score both predict hypertriglyceridemia and cardiovascular disease risk.

BACKGROUND: Evidence on the causal link between plasma triglyceride (TG) levels and risk for cardiovascular disease (CVD) has recently emerged. Individuals with the metabolic syndrome have an increased risk for acquiring elevated TG levels later in life. Moreover, common DNA sequence variations in genes affecting TG levels identify individuals at risk for elevated plasma TG levels. OBJECTIVE: We evaluated whether a 3-single nucleotide polymorphism (SNP) TG gene risk score (GRS) and a metabolic risk score (MetRS) both improved CVD risk prediction. METHODS: A 3-SNP GRS and MetRS were generated in the EPIC-Norfolk cohort (n = 20,074) based on 3 SNPs in LPL and APOA5 or the number of Metabolic Syndrome criteria present (maximum 5), respectively. The associations between the 3-SNP GRS, MetRS, TG levels, and CVD risk were evaluated. RESULTS: The 3-SNP GRS and MetRS were both linearly associated with plasma TG levels, that is, +0.25 mmol/L [95% CI 0.22-0.27] per allele change (P < .001) and +0.72 mmol/L [95% CI 0.70-0.73] per increase of number of metabolic syndrome risk score points (P < .001), respectively. We observed a positive association between the 3-SNP GRS and the risk of CVD with an adjusted hazard ratio (HR) of 1.35 [95% CI 1.04-1.74] for the highest versus the lowest GRS, which was independent of the MetRS. For the MetRS, the adjusted HR was 2.03 [95% CI 1.73-2.40] for the highest versus the lowest MetRS. CONCLUSION: Both the 3-SNP GRS and the MetRS are associated with increased plasma TG levels and increased risk for CVD.

Elevated lipoprotein(a) levels are associated with coronary artery calcium scores in asymptomatic individuals with a family history of premature atherosclerotic cardiovascular disease.

BACKGROUND: Elevated lipoprotein(a) (Lp(a)) levels are associated with increased risk for atherosclerotic cardiovascular disease (ASCVD). Individuals with a family history of premature ASCVD are at increased cardiovascular risk with concomitantly a higher burden of (subclinical) atherosclerosis. However, whether Lp(a) contributes to the increased atherosclerotic burden in these individuals remains to be established. OBJECTIVE: In this study, we evaluated the association between Lp(a) levels and coronary atherosclerotic burden, assessed by coronary arterty calcium (CAC) scores, in asymptomatic individuals with a family history of premature ASCVD. METHODS: Lp(a) levels and other ASCVD risk factors were assessed in 432 individuals with premature ASCVD and in 937 healthy asymptomatic family members. CAC scores were only measured in asymptomatic family members. RESULTS: In this cohort, 16% had elevated Lp(a) levels, defined as ≥ 50 mg/dL. Among healthy family members, elevated Lp(a) levels were associated with both absolute CAC scores of ≥ 100 (odds ratio [OR] 1.79 [95% confidence interval {CI} 1.13-2.83]) as well as with age- and gender-corrected CAC scores ≥ 80th percentile (OR 1.69 [95% CI 1.14-2.50]). This coincides with a higher prevalence of cardiovascular events (OR 1.48 [95% CI 1.11-2.01]) in the whole cohort. CONCLUSION: Elevated Lp(a) levels were associated with higher CAC scores, both absolute as well as age- and gender-corrected percentiles, in individuals with a family history of premature ASCVD. These data imply that Lp(a) accelerates progression of atherosclerosis in these individuals, thereby contributing to their increased ASCVD risk.

Relationship of lipoprotein-associated apolipoprotein C-III with lipid variables and coronary artery disease risk: The EPIC-Norfolk prospective population study.

BACKGROUND: Plasma apolipoprotein C-III (apoC-III) levels are associated with coronary artery disease (CAD) risk. OBJECTIVE: To assess whether lipoprotein-associated apoC-III levels predict risk of CAD events. METHODS: apoC-III associated with apoB, apoAI, and Lp(a) (apoCIII-apoB, apoCIII-apoAI, and apoCIII-Lp(a), respectively) were measured using high-throughput chemiluminescent enzyme-linked immunoassays in 2711 subjects (1879 controls and 832 cases with CAD) in the European Prospective Investigation into Cancer and Nutrition-Norfolk prospective population study with 7.4 years of follow-up. These measures were correlated with a variety of lipid measurements and the presence of CAD. The indices of "total apoCIII-apoB" and "total apoCIII-apoAI" were derived by multiplying plasma apoB and apoAI, respectively. RESULTS: apoCIII-apoB (P = .001), apoCIII-Lp(a) (P < .001), apoCIII-apoAI (P = .005) were higher in cases vs controls; tended to correlate positively with body mass index, hsCRP, apoC-III, low-density lipoprotein (LDL) cholesterol, triglycerides, remnant cholesterol, very low density lipoprotein, LDL and high-density lipoprotein particle number and very low density lipoprotein size; but negatively with LDL and high-density lipoprotein particle size (P < .001 for all). apoCIII-apoB, apoCIII-apoAI, apoCIII-Lp(a), total apoCIII-Lp(a), and total apoCIII-apoB were predictors of CAD after adjustment of age, sex, body mass index, smoking, diabetes, hypertensive and lipid-lowering drug use, but they lost their significance after further adjustment of lipid and lipoprotein variables. CONCLUSIONS: This study suggests that enzyme-linked immunoassay-measured lipoprotein-associated apoC-III markers reflect atherogenic lipid particles but do not independently predict risk of CAD events.

Ideal cardiovascular health influences cardiovascular disease risk associated with high lipoprotein(a) levels and genotype: The EPIC-Norfolk prospective population study.

BACKGROUND AND AIMS: Lipoprotein(a) (Lp[a]) is a strong genetic risk factor for cardiovascular disease (CVD). The American Heart Association has prioritised seven cardiovascular health metrics to reduce the burden of CVD: body mass index, healthy diet, physical activity, smoking status, blood pressure, diabetes and cholesterol levels (together also known as ideal cardiovascular health). Our objective was to determine if individuals with high Lp(a) levels could derive cardiovascular benefits if characterized by ideal cardiovascular health. METHODS: A total of 14,051 participants of the EPIC-Norfolk study were stratified according to the cardiovascular health score (based on the number of health metrics with an ideal, intermediate or poor status). Of them, 1732 had a CVD event during a mean follow-up of 11.5 years. Cox proportional hazards models were used to describe the association between the cardiovascular health score and Lp(a) level or genotype (as estimated by the rs10455872 variant) with the risk of CVD. RESULTS: We observed little or no differences in serum Lp(a) levels across the seven cardiovascular health metric categories. Among participants with high serum Lp(a) levels ≥50 mg/dl), those in the highest (i.e. healthiest) cardiovascular health score category (10-14) had an adjusted hazard ratio for cardiovascular disease of 0.33 (95% CI = 0.17-0.63, p = 0.001) compared to participants in the lowest (i.e. unhealthiest) cardiovascular health score category(0-4). Similar results were obtained when we replaced Lp(a) with rs10455872. CONCLUSIONS: Although Lp(a) levels are only slightly influenced by cardiovascular health metrics, an ideal cardiovascular health could substantially reduce CVD risk associated with high Lp(a) levels or genotype.

PCSK9 inhibitors: Novel therapeutic agents for the treatment of hypercholesterolemia.

Reducing plasma levels of low-density lipoprotein cholesterol (LDL-c) remains the cornerstone in the primary and secondary prevention of cardiovascular disease. However, a substantial proportion of patients fail to achieve acceptable LDL-c levels with currently available lipid-lowering drugs. Over the last decade, inhibition of Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) has emerged as a promising target to reduce residual cardiovascular disease risk. Binding of PCSK9 to the LDL receptor targets the LDL receptor for lysosomal degradation. Inhibition of PCSK9 increases expression of the LDL receptor. This observation has led to the development of a number of approaches to directly target PCSK9. Three monoclonal antibodies against PCSK9 are currently being evaluated in phase 3 trials involving various patient categories on different background lipid lowering therapies. Current evidence shows reductions in LDL cholesterol levels of up to 70%, independent of background statin therapy. The results of phase 3 trials will demonstrate the long-term efficacy and safety of PCSK9 inhibition, and will indicate whether LDL-c lowering induced by this novel approach translates into beneficial effects on CVD outcome.