Lipoprotein(a) levels from childhood to adulthood: Data in nearly 3,000 children who visited a pediatric lipid clinic

Temporal variability of Lp(a) in clinically stable patients: Implications for cardiovascular risk assessment

OBJECTIVES

Lipoprotein(a) [Lp(a)] is a significant risk factor for cardiovascular disease, yet it is often overlooked in routine clinical assessments. As a primarily genetically determined risk factor, the traditional recommendation is to assess its level once in a lifetime, as the variability of Lp(a) over time is considered to be minimal. This study aims to evaluate the potential variability of Lp(a) in clinically stable patients and investigate factors contributing to the lack of stable levels.

METHODS

A retrospective analysis was conducted on a sample of adult patients attending a lipid clinic. Participants with at least two Lp(a) measurements taken with a minimum interval of four months were included. Lp(a) measurements were performed using the immunoturbidimetric assay. Variability in Lp(a) values was calculated as a percentage change from baseline, with participants exceeding a 25% change classified as having hypervariable Lp(a) levels. Additional clinical and biochemical variables were assessed.

RESULTS

61 participants with 171 Lp(a) determinations were included. Thirty-four percent exhibited a variability of 25% or higher (hypervariable). Men showed slightly greater variability than women. Changes in Lp(a) categories were observed among hypervariable patients, with some participants experiencing an increase while others showed a decrease. Menopause was present in all the women with hypervariable levels.

CONCLUSION

Our study suggests reconsidering the reliance on a single Lp(a) measurement for assessing cardiovascular risk. Repeat measurements, particularly in borderline cases, may be beneficial.

The association between lipoprotein(a) levels and ischemic stroke in children: A case-control study

BACKGROUND

Pediatric arterial ischemic stroke (AIS) is a rare disorder, associated with severe morbidity. In adults, elevated lipoprotein(a) (Lp(a)), a cholesterol-like particle, is associated with ischemic stroke. However, data on Lp(a) and pediatric AIS are scarce. Therefore, we evaluated the association between Lp(a) levels and pediatric AIS.

METHODS

We included children who suffered an AIS (≤18 years) and were treated in a tertiary center in Amsterdam, the Netherlands. Two groups of children with AIS were identified: (i) neonates and (ii) children older than 29 days. A case-control study was performed, with the latter group as cases and children without AIS as control group. Cases and controls were matched for age of Lp(a) testing and sex. Multivariable logistic regression models were used.

RESULTS

Thirteen neonates and 23 children were included. Mean (SD) age of AIS was 0.6 (2.0) days and 9.2 (6.3) years, respectively. Children with AIS were matched to 62 controls. Lp(a) levels of greater than 50 mg/dL were more prevalent in children with AIS compared to controls (21.7% vs. 3.2%, p = .02). A significant association was found between Lp(a) and AIS (odds ratio [OR] adjusted for age at Lp(a) testing, body mass index [BMI], measurement assay: 1.36 per 10 mg/dL increase of Lp(a), 95% confidence interval [CI]: 1.02-1.82, p = .041).

CONCLUSIONS

In this study, Lp(a) levels were positively associated with the risk of AIS in children, suggesting that high Lp(a) might be an independent risk factor for AIS. This underlines the importance of Lp(a) measurement in children with AIS.

Is lipoprotein(a) measurement important for cardiovascular risk stratification in children and adolescents?

BACKGROUND

Elevated lipoprotein (Lp(a)) levels are associated with increased risk of atherosclerotic processes and cardiovascular events in adults. The amount of Lp(a) is mainly genetically determined. Therefore, it is important to identify individuals with elevated Lp(a) as early as possible, particularly if other cardiovascular risk factors are present. The purpose of the study was to investigate whether, in a population of children and adolescents already followed for the presence of one or more cardiovascular risk factors (elevated blood pressure (BP), and/or excess body weight, and/or dyslipidemia), the measurement of Lp(a) can be useful for better stratifying their risk profile.

METHODS

In a sample of 195 children and adolescents, height, body weight, waist circumference and systolic (SBP) and diastolic (DBP) BP were measured. Body Mass Index (BMI) and SBP and DBP z-scores were calculated. Plasma Lp(a), total cholesterol, high-density lipoprotein (HDL), triglycerides, glucose, insulin, uric acid and creatinine were assessed. Low-density lipoprotein (LDL) cholesterol was calculated with the Friedewald formula. High Lp(a) was defined as ≥ 75 nmol/L and high LDL cholesterol as ≥ 3.37 mmol/L.

RESULTS

Our sample of children and adolescents (54.4% males, mean age 11.5 years) had median LDL cholesterol and Lp(a) values equal to 2.54 (interquartile range, IQR: 2.07-3.06) mmol/L and 22 (IQR: 7.8-68.6) nmol/L respectively. 13.8% of children had LDL cholesterol ≥ 3.37 mmol/L and 22.6 Lp(a) values ≥ 75 nmol/L. Lp(a) values were higher in children of normal weight than in those with excess weight (p = 0.007), but the difference disappeared if normal weight children referred for dyslipidemia only were excluded from the analysis (p = 0.210). 69.4% of children had normal Lp(a) and LDL cholesterol values and only 6.2% showed both elevated Lp(a) and LDL cholesterol levels. However, 16.6% of the sample, despite having normal LDL cholesterol, had elevated Lp(a) values. Multivariable analyses showed a significant association of LDL cholesterol both with Lp(a) values, and with the presence of elevated Lp(a) levels. For each mmol/L increase in LDL cholesterol the risk of having an elevated Lp(a) value increased by 73%. There was an inverse correlation between BMI z-score and Lp(a). Neither BP z-scores, nor other biochemical parameters were associated with Lp(a).

CONCLUSIONS

In our population more than one out of five children had elevated Lp(a) values, and in about 17% of children elevated Lp(a) values were present in the absence of increased LDL cholesterol. Our results suggest that Lp(a) measurement can be useful to better define the cardiovascular risk profile in children and adolescents already followed for the presence of other cardiovascular risk factors such as elevated BP, excess body weight and high LDL cholesterol.

Lipoprotein(a) in children and adolescents with genetically confirmed familial hypercholesterolemia followed up at a specialized lipid clinic

Background and aim

Many children with an FH mutation also exhibit elevated lipoprotein(a) levels, which is an independent risk factor for atherosclerotic cardiovascular disease. Studies have reported higher levels of lipoprotein(a) in adult and middle-aged women than men. There is limited knowledge on the concentration and change of lipoprotein(a) levels in children with genetic FH, and therefore we investigated sex-differences in lipoprotein(a) level and change in lipoprotein(a) in girls and boys with genetically confirmed FH.

Methods

Medical records were reviewed retrospectively in 438 subjects with heterozygous FH that started follow-up below the age of 19 years at the Lipid Clinic, Oslo University Hospital in Norway, and of these we included 386 subjects with at least one Lp(a) measurement.

Results

Mean (SD) age at baseline was 13.8 (7.3) years and the age was similar between sexes. Girls had a higher lipoprotein(a) level than boys at baseline: median (25-75 percentile) 223 (108-487) vs. 154 (78-360) mg/L, respectively (p < 0.01). From baseline to follow-up measurement (mean [SD] 8.9 [6.1] years apart), the mean (95 % CI) absolute and percentage change in Lp(a) level in girls was 151.4 (54.9-247.8) mg/L and 44.8 (16.4-73.1) %, respectively, and in boys it was 66.8 (22.9-110.8) mg/L and 50.5 (8.8-92.3) %, respectively (both p > 0.05).

Conclusions

We found an increase in Lp(a) levels in children with genetic FH with age, and higher levels in girls than boys, which could impact risk assessment and future ASCVD. Further research is needed to elucidate whether subjects with FH could benefit from lipoprotein(a)-lowering therapies that are under current investigations.

Lipoprotein(a) in Children and Adolescents: Risk or Causal Factor for Cardiovascular Disease? A Narrative Review

The evaluation of serum Lp(a) values in childhood and adolescence has been widely debated, and in the last few years, many authors have tried to better define Lp(a) role in atherosclerosis pathogenesis, starting from childhood. In our narrative review, we have evaluated the main historical stages of Lp(a) studies in childhood, trying to focus on pathogenic mechanisms linked to elevated serum Lp(a) values, starting from ischemic stroke and vascular damage, and to its possible direct involvement in premature atherosclerosis from childhood onwards. Historic manuscripts on Lp(a) in pediatric patients have mainly focused on serum Lp(a) values and increased stroke risk. More recently, many studies have evaluated Lp(a) as a coronary vascular disease (CVD) risk factor starting from childhood, especially related to a positive family history of premature CVD. Finally, only a few studies evaluated the role of Lp(a) in premature atherosclerotic processes and endothelial and vascular damage in pediatric patients. Lastly, we have hypothesized a future perspective, with the hope that plasma Lp(a) levels will be treated with a tailored pharmacologic approach, and Lp(a) will become a precocious therapeutic target to control the atherosclerotic pathways from the first years of life.

Lipoprotein(a) in interventional cardiology: identifying patients at highest risk of recurrent cardiovascular events through early recognition - a case based review

INTRODUCTION

Lipoprotein(a) [Lp(a)] is linked to higher risks of atherosclerotic cardiovascular disease (ASCVD). Current guideline recommendations are quite liberal on measuring Lp(a) (Class IIa, Level C), and may lead to underuse among (interventional) cardiologists.

AREAS COVERED

This case-based narrative review outlines four clinical cases of patients with elevated Lp(a) to illustrate its pathophysiological impact on coronary artery disease (CAD). The expert consensus statements from the American Heart Association (AHA) and European Atherosclerosis Society (EAS) served as the basis of this review. More recent publications, from 2023 to 2024, were accessed through the MEDLINE online library.

EXPERT OPINION

We highlighted the importance of routine Lp(a) measurement in identifying patients at high risk for atherosclerosis, necessitating potent risk mitigation. Measuring Lp(a) helps clinicians identify which patients are at highest residual risk, who require potent pharmacological treatment and special attention during catheter interventions. As noninvasive and advanced intravascular imaging modalities evolve, future catheterization laboratories will integrate advanced imaging, diagnostics, and treatment, facilitating tailored patient care. Knowing Lp(a) levels is crucial in this context. While Lp(a)-lowering drugs are currently investigated in clinical trials, it is of paramount importance to know Lp(a) levels and strive toward aggressive management of other modifiable risk factors in patients with elevated Lp(a) and established symptomatic CAD being diagnosed or treated in catheterization laboratories.

Lipoprotein (a) and cerebrovascular disease

The role of lipoprotein (a) [Lp(a)] in cerebrovascular disease is a topic of importance. In this narrative review, pertinent studies have been leveraged to comprehensively examine this relationship from diverse perspectives.Lp(a) shares structural traits with low-density lipoprotein cholesterol. Lp(a) is synthesized by hepatocytes, and its plasma levels are genetically determined by the LPA gene, which produces apolipoprotein (a).Numerous epidemiological studies have confirmed the positive correlation between elevated serum Lp(a) levels and the occurrence or recurrence of cerebrovascular events, especially ischemic strokes, in adults. It should be noted that the correlation strength varies among studies and is marginal in Mendelian randomization studies.Regarding pediatric patients, screening is currently limited to those with a relevant medical history. Lp(a) seems to play a significant role in the pathogenesis of arterial ischemic stroke in children because environmental thrombotic and atherogenic factors are generally not present.Phase 3 trials of novel Lp(a) targeting agents, such as pelacarsen and olpasiran, are anticipated to demonstrate their efficacy in reducing the incidence of stroke. Given the richness of the literature, new guidelines regarding Lp(a) screening and management in targeted populations are warranted to provide more effective primary and secondary prevention.

Lipoprotein(a) serum concentrations in children in relation to body mass index, age and sex

BACKGROUND

Lipoprotein(a) (Lp(a)) is an inherited risk factor for atherosclerotic cardiovascular disease (ASCVD). Limited data exist on Lp(a) values in children. We aimed to evaluate whether Lp(a) concentrations in youth are influenced by BMI.

METHODS

756 blood samples of 248 children with obesity and 264 matched healthy children aged 5 and 18 years, enrolled in the population-based LIFE Child (German civilization diseases cohort) study, were analyzed. Repeat measurements were available in 154 children (1-4 follow ups, ~1 year apart).

RESULTS

The median Lp(a) concentration in the total cohort (n = 512) at first visit was 9.7 mg/dL (IQR 4.0-28.3). Lp(a) concentrations between 30-50 mg/dL were observed in 11.5%, while 12.5% exhibited Lp(a) ≧50 mg/dL. There was no association of Lp(a) with body mass index (BMI) (ß = 0.004, P = 0.49). Lp(a) levels did not correlate with age or sex, while Lp(a) was associated positively with low-density lipoprotein cholesterol (ß = 0.05, P < 0.0001). The Lp(a) risk category remained stable in 94% of all children in repeated measurements.

CONCLUSIONS

The data showed no association of Lp(a) levels in children with BMI, age or sex. Measurement of Lp(a) in youth may be useful to identify children at increased lifetime risk for ASCVD.

IMPACT

In youth, Lp(a) levels are not affected by age, sex and BMI. Lp(a) risk categories remain stable over time in repeated measurements in children. Measurement of Lp(a) in children may be useful as an additional factor to identify children at increased lifetime risk for ASCVD and for reverse family screening.

Canadian Society of Clinical Chemists Harmonized Pediatric Lipid Reporting Recommendations for Clinical Laboratories

Detecting dyslipidemia early is important because atherosclerosis originates in childhood and early treatment can improve outcomes. In 2022, the Canadian Cardiovascular Society (CCS) and Canadian Pediatric Cardiology Association (CPCA) published a clinical practice update to detect, evaluate, and manage pediatric dyslipidemia. However, guidance on its translation into clinical laboratories is lacking. The Canadian Society of Clinical Chemists Working Group on Reference Interval Harmonization Lipid Team aims to assist guideline implementation and promote harmonized pediatric lipid reporting across Canada. The 2022 CCS/CPCA clinical practice update, 2011 National Heart, Lung, and Blood Institute integrated guidelines, and new data analysis (Canadian pediatric reference values from the Canadian Laboratory Initiative on Pediatric Reference Intervals [CALIPER] and retrospective patient data from large community laboratories) were incorporated to develop 5 key recommendations. These include recommendations to: (1) offer nonfasting and fasting lipid testing; (2) offer a lipid panel including total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, and triglycerides, with apolipoprotein B and lipoprotein(a) available as individually orderable tests; (3) flag total cholesterol, LDL-C, and non-HDL-C results ≥ 95th percentile, and HDL-C results < 10th percentile, as recommended by CCS/CPCA/National Heart, Lung, and Blood Institute and validated by CALIPER, and flag apolipoprotein B and nonfasting triglyceride results ≥ 95th percentile on the basis of CALIPER, and do not flag Lp(a) results but mention the adult cutoff in the interpretive comments; (4) implement interpretive comments listed in the current report; and (5) implement the National Institutes of Health LDL-C equation. The Canadian Society of Clinical Chemists Working Group on Reference Interval Harmonization Lipid Team will support clinical laboratories to implement these recommendations using knowledge translation strategies. Harmonizing pediatric lipid reporting across Canadian clinical laboratories will optimize clinical decision-making and improve cardiovascular risk management in youth.

High lipoprotein(a): Actionable strategies for risk assessment and mitigation

High levels of lipoprotein(a) [Lp(a)] are causal for atherosclerotic cardiovascular disease (ASCVD). Lp(a) is the most prevalent inherited dyslipidemia and strongest genetic ASCVD risk factor. This risk persists in the presence of at target, guideline-recommended, LDL-C levels and adherence to lifestyle modifications. Epidemiological and genetic evidence supporting its causal role in ASCVD and calcific aortic stenosis continues to accumulate, although various facets regarding Lp(a) biology (genetics, pathophysiology, and expression across race/ethnic groups) are not yet fully understood. The evolving nature of clinical guidelines and consensus statements recommending universal measurements of Lp(a) and the scientific data supporting its role in multiple disease states reinforce the clinical merit to start population screening for Lp(a) now. There is a current gap in the implementation of recommendations for primary and secondary cardiovascular disease (CVD) prevention in those with high Lp(a), in part due to a lack of protocols for management strategies. Importantly, targeted apolipoprotein(a) [apo(a)]-lowering therapies that reduce Lp(a) levels in patients with high Lp(a) are in phase 3 clinical development. This review focuses on the identification and clinical management of patients with high Lp(a). Specifically, we highlight the clinical value of measuring Lp(a) and its use in determining Lp(a)-associated CVD risk by providing actionable guidance, based on scientific knowledge, that can be utilized now to mitigate risk caused by high Lp(a).

A focused update to the 2019 NLA scientific statement on use of lipoprotein(a) in clinical practice

Since the 2019 National Lipid Association (NLA) Scientific Statement on Use of Lipoprotein(a) in Clinical Practice was issued, accumulating epidemiological data have clarified the relationship between lipoprotein(a) [Lp(a)] level and cardiovascular disease risk and risk reduction. Therefore, the NLA developed this focused update to guide clinicians in applying this emerging evidence in clinical practice. We now have sufficient evidence to support the recommendation to measure Lp(a) levels at least once in every adult for risk stratification. Individuals with Lp(a) levels <75 nmol/L (30 mg/dL) are considered low risk, individuals with Lp(a) levels ≥125 nmol/L (50 mg/dL) are considered high risk, and individuals with Lp(a) levels between 75 and 125 nmol/L (30-50 mg/dL) are at intermediate risk. Cascade screening of first-degree relatives of patients with elevated Lp(a) can identify additional individuals at risk who require intervention. Patients with elevated Lp(a) should receive early, more-intensive risk factor management, including lifestyle modification and lipid-lowering drug therapy in high-risk individuals, primarily to reduce low-density lipoprotein cholesterol (LDL-C) levels. The U.S. Food and Drug Administration approved an indication for lipoprotein apheresis (which reduces both Lp(a) and LDL-C) in high-risk patients with familial hypercholesterolemia and documented coronary or peripheral artery disease whose Lp(a) level remains ≥60 mg/dL [∼150 nmol/L)] and LDL-C ≥ 100 mg/dL on maximally tolerated lipid-lowering therapy. Although Lp(a) is an established independent causal risk factor for cardiovascular disease, and despite the high prevalence of Lp(a) elevation (∼1 of 5 individuals), measurement rates are low, warranting improved screening strategies for cardiovascular disease prevention.

Clinical-epidemiological analysis of patients with elevated lipoprotein A in a third level hospital

OBJECTIVE

The objective of the study is to describe the clinical and epidemiological characteristics of our patients with elevated Lp(a).

MATERIALS AND METHODS

A descriptive cross-sectional study was conducted on 316 patients with elevated Lp(a) (>125 nmol/L) in a random sample between January and August 2022. We measured epidemiological, anthropometric, clinical and laboratory variables (lipid metabolism parameters, carbohydrates and hormones).

RESULTS

Mean age of our sample subject's was 59 ± 15 years with 56% males. The average BMI was 27.6 kg/m2 (71% with elevated BMI). Elevated waist circumference was observed in 54.1% of men and 77.8% of women. 48% had hypertension, 30.7% had diabetes mellitus and 91.5% dyslipidemia. Only 39.7% of the patients had never smoked. The mean values of total cholesterol were 158 ± 45 mg/dl, LDL was 81 ± 39 mg/dl, HDL was 53 ± 17 mg/dl, Triglycerides were 127 ± 61 mg/dl, and Lp(a) was 260 ± 129 nmol/L. Regarding lipid lowering treatment, 89% were on statins, 68.6% on ezetimibe, and 13.7% on PCSK9 inhibitors. 177 patients (57,7%) had established cardiovascular disease (CVD), 16.3% had polyvascular disease, 11.7% had subclinical CVD, and 30.6% had no known CVD. Among patients with established CVD, 174 (98.3%) were on lipid-lowering treatment (97.2% on statins) and 86.4% were on antiplatelet therapy. The mean age of cardiovascular events was 55 ± 12 years in males and 60 ± 11 years in females. 65,1% of female and 56,2% of male patients suffered an early cardiovascular event.

CONCLUSIONS

Patients with elevated Lp(a) are at very high cardiovascular risk, particularly for early cardiovascular disease.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolaemia: An expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is used for decades, lowering serum LDL-C levels by more than 70% directly after the treatment. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment goals and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Lipoprotein(a): A Review of Risk Factors, Measurements, and Novel Treatment Modalities

The study of lipoprotein(a) [Lp(a)] has long been a source of interest as a possible independent risk factor for atherosclerotic cardiovascular disease (ASCVD). The results of large sample observational studies, genome-wide association studies, and Mendelian randomization studies have been strong indicators supporting the link between ASCVD and Lp(a) despite early studies, with less sensitive assays, failing to show a connection. The recommendations for the indications and frequency of testing Lp(a) levels vary between US, Canadian, and European organizations due to the uncertain role of Lp(a) in ASCVD. The innovation of recent therapies, such as antisense oligonucleotides and small interfering RNA, designed to specifically target and reduce Lp(a) levels by targeting mRNA translation have once more thrust LP(a) into the spotlight of inquiry. These emerging modalities serve the dual purpose of definitively elucidating the connection between elevated Lp(a) levels and atherosclerotic cardiovascular risk, as well as the possibility of providing clinicians with the tools necessary to manage elevated Lp(a) levels in vulnerable populations. This review seeks to examine the mechanisms of atherogenicity of Lp(a) and explore the most current pharmacologic therapies currently in development.

LP(a): Structure, Genetics, Associated Cardiovascular Risk, and Emerging Therapeutics

Lipoprotein(a) [Lp(a)] is a molecule bound to apolipoprotein(a) with some similarity to low-density lipoprotein cholesterol (LDL-C), which has been found to be a risk factor for cardiovascular disease (CVD). Lp(a) appears to induce inflammation, atherogenesis, and thrombosis. Approximately 20% of the world's population has increased Lp(a) levels, determined predominantly by genetics. Current clinical practices for the management of dyslipidemia are ineffective in lowering Lp(a) levels. Evolving RNA-based therapeutics, such as the antisense oligonucleotide pelacarsen and small interfering RNA olpasiran, have shown promising results in reducing Lp(a) levels. Phase III pivotal cardiovascular outcome trials [Lp(a)HORIZON and OCEAN(a)] are ongoing to evaluate their efficacy in secondary prevention of major cardiovascular events in patients with elevated Lp(a). The future of cardiovascular residual risk reduction may transition to a personalized approach where further lowering of either LDL-C, triglycerides, or Lp(a) is selected after high-intensity statin therapy based on the individual risk profile and preferences of each patient.

Prediction of atherosclerotic cardiovascular risk in early childhood

Atherosclerotic lesions are present even in very young individuals and therefore, risk stratification for cardiovascular (CV) disease should be implemented in childhood to promote early prevention strategies. In this review we critically appraise clinical, biochemical and genetic biomarkers available for pediatric clinical practice, which might be integrated to build effective algorithms to identify children at risk of future CV events. The first critical issue is to characterize in children aged 2-5 years, those CV risk factors/clinical conditions associated with dramatically accelerated atherosclerosis. Presence of clinical conditions such as obesity, diabetes mellitus, Kawasaki disease, etc., or positive family history for premature CV disease should be evaluated. Subsequently, a complete lipid profile and Lipoprotein(a) determination are recommended for children with increased baseline CV risk. Individuals with altered lipid profile could then undergo genetic testing for monogenic dyslipidemias to identify children with high CV genetic risk, who will be directed to appropriate therapeutic options. In perspective, calculation of a polygenic risk score, based on the analysis of several common single-nucleotide polymorphisms, could be integrated for better risk assessment. We here emphasize the importance of a "holistic" strategy integrating biochemical, anamnestic and genetic data to stratify CV risk in early childhood.

Cascade testing of children and adolescents for elevated Lp(a) in pedigrees with familial hypercholesterolaemia

Elevated plasma lipoprotein(a) [Lp(a)] is a common, inherited condition independently causing cardiovascular disease. Recent expert recommendations suggest opportunistically testing for elevated Lp(a) during cascade testing for familial hypercholesterolaemia (FH). We investigated the effectiveness of detecting elevated Lp(a) in 103 children and adolescents who were first-degree relatives of 66 adult index FH cases as part of an established FH cascade screening program. The yield of detection of elevated Lp(a) using a threshold of ≥30 mg/dL in children and adolescents was assessed. Cascade testing from FH index cases with elevated Lp(a) ≥50 mg/dL identified 1 case of Lp(a) ≥30 mg/dL for every 2 children or adolescents tested. In contrast, opportunistic screening from index cases with FH but normal Lp(a) levels demonstrated 1 case of Lp(a) ≥30 mg/dL for every 7.5 children or adolescents tested (p < 0.001). In conclusion, cascade testing for elevated Lp(a) from index cases with FH and elevated Lp(a) is effective in identifying new cases of elevated Lp(a).

Concordance of a High Lipoprotein(a) Concentration Among Relatives

Importance

Lipoprotein(a) (Lp[a]) concentrations are a highly heritable and potential causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Recent consensus statements by the European Atherosclerosis Society and American Heart Association recommend screening of relatives of individuals with high Lp(a) concentrations, but the expected yield of this approach has not been quantified in large populations.

Objective

To measure the prevalence of high Lp(a) concentrations among first- and second-degree relatives of individuals with high Lp(a) concentrations compared with unrelated participants.

Design, Setting, and Participants

In this cross-sectional analysis, pairs of first-degree (n = 19 899) and second-degree (n = 9715) relatives with measured Lp(a) levels from the UK Biobank study and random pairs of unrelated individuals (n = 184 764) were compared. Data for this study were collected from March 2006 to August 2010 and analyzed from December 2021 to August 2023.

Exposure

Serum Lp(a) levels, with a high Lp(a) level defined as at least 125 nmol/L.

Main Outcome and Measure

Concordance of clinically relevant high Lp(a) levels in first- and second-degree relatives of index participants with high Lp(a) levels.

Results

A total of 52 418 participants were included in the analysis (mean [SD] age, 57.3 [8.0] years; 29 825 [56.9%] women). Levels of Lp(a) were correlated among pairs of first-degree (Spearman ρ = 0.45; P < .001) and second-degree (Spearman ρ = 0.22; P < .001) relatives. A total of 1607 of 3420 (47.0% [95% CI, 45.3%-48.7%]) first-degree and 514 of 1614 (31.8% [95% CI, 29.6%-34.2%]) second-degree relatives of index participants with high Lp(a) levels also had elevated concentrations compared with 4974 of 30 258 (16.4% [95% CI, 16.0%-16.9%]) pairs of unrelated individuals. The concordance in high Lp(a) levels was generally consistent among subgroups (eg, those with prior ASCVD, postmenopausal women, and statin users). The odds ratios for relatives to have high Lp(a) levels if their index relative had a high Lp(a) level compared with those whose index relatives did not have high Lp(a) levels were 7.4 (95% CI, 6.8-8.1) for first-degree relatives and 3.0 (95% CI, 2.7-3.4) for second-degree relatives.

Conclusions and Relevance

The findings of this cross-sectional study suggest that the yield of cascade screening of first-degree relatives of individuals with high Lp(a) levels is over 40%. These findings support recent recommendations to use this approach to identify additional individuals at ASCVD risk based on Lp(a) concentrations.

Lipoprotein(a): a genetically determined risk factor for Cardiovascular disease

Lipoprotein(a) is a complex lipoprotein with unique characteristics distinguishing it from all the other apolipoprotein B-containing lipoprotein particles. Its lipid composition and the presence of a single molecule of apolipoprotein B per particle, render lipoprotein(a) similar to low-density lipoproteins. However, the presence of a unique, carbohydrate-rich protein termed apolipoprotein(a), linked by a covalent bond to apolipoprotein B imparts unique characteristics to lipoprotein(a) distinguishing it from all the other lipoproteins. Apolipoprotein(a) is highly polymorphic in size ranging in molecular weight from <300 KDa to >800 kDa. Both the size polymorphism and the concentration of lipoprotein(a) in plasma are genetically determined and unlike other lipoproteins, plasma concentration is minimally impacted by lifestyle modifications or lipid-lowering drugs. Many studies involving hundreds of thousands of individuals have provided strong evidence that elevated lipoprotein(a) is genetically determined and a causal risk factor for atherosclerotic cardiovascular disease. The concentration attained in adulthood is already present in children at around 5 years of age and therefore, those with elevated lipoprotein(a) are prematurely exposed to a high risk of cardiovascular disease. Despite the large number of guidelines and consensus statements on the management of lipoprotein(a) in atherosclerotic cardiovascular disease published in the last decade, lipoprotein(a) is still seldom measured in clinical settings. In this review, we provide an overview of the most important features that characterize lipoprotein(a), its role in cardiovascular disease, and the importance of adding the measurement of lipoprotein(a) for screening adults and youths to identify those at increased risk of atherosclerotic cardiovascular disease due to their elevated plasma concentration of lipoprotein(a).

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolemia: an expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is well established since three decades, lowering serum LDL-C levels by more than 70% per session. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment targets and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Lipoprotein(a)-60 Years Later-What Do We Know?

Lipoprotein(a) (Lp(a)) molecule includes two protein components: apolipoprotein(a) and apoB100. The molecule is the main transporter of oxidized phospholipids (OxPL) in plasma. The concentration of this strongly atherogenic lipoprotein is predominantly regulated by the LPA gene expression. Lp(a) is regarded as a risk factor for several cardiovascular diseases. Numerous epidemiological, clinical and in vitro studies showed a strong association between increased Lp(a) and atherosclerotic cardiovascular disease (ASCVD), calcific aortic valve disease/aortic stenosis (CAVD/AS), stroke, heart failure or peripheral arterial disease (PAD). Although there are acknowledged contributions of Lp(a) to the mentioned diseases, clinicians struggle with many inconveniences such as a lack of well-established treatment lowering Lp(a), and common guidelines for diagnosing or assessing cardiovascular risk among both adult and pediatric patients. Lp(a) levels are different with regard to a particular race or ethnicity and might fluctuate during childhood. Furthermore, the lack of standardization of assays is an additional impediment. The review presents the recent knowledge on Lp(a) based on clinical and scientific research, but also highlights relevant aspects of future study directions that would approach more suitable and effective managing risk associated with increased Lp(a), as well as control the Lp(a) levels.

Lipoprotein(a) and carotid intima-media thickness in children with familial hypercholesterolaemia in the Netherlands: a 20-year follow-up study

BACKGROUND

Elevated lipoprotein(a) and familial hypercholesterolaemia are both independent risk conditions for cardiovascular disease. Although signs of atherosclerosis can be observed in children with familial hypercholesterolaemia, it is unknown whether elevated lipoprotein(a) is an additional risk factor for atherosclerosis in these young patients. Therefore, we aimed to assess the contribution of lipoprotein(a) concentrations to arterial wall thickening (as measured by carotid intima-media thickness) in children with familial hypercholesterolaemia who were followed up into adulthood.

METHODS

We conducted a 20-year follow-up study of 214 children (aged 8-18 years) with heterozygous familial hypercholesterolaemia who were randomly assigned in a statin trial in Amsterdam (Netherlands) between Dec 7, 1997, and Oct 4, 1999. At baseline, and at 2, 10, and 20 years thereafter, blood samples were taken and carotid intima-media thickness was measured. Linear mixed-effects models were used to evaluate the association between lipoprotein(a) and carotid intima-media thickness during follow-up. We adjusted for sex, age, corrected LDL-cholesterol, statin use, and BMI.

FINDINGS

Our study population comprised 200 children who had a carotid intima-media thickness measurement and a measured lipoprotein(a) concentration from at least one visit available. Mean age at baseline was 13·0 years (SD 2·9), 106 (53%) children were male, and 94 (47%) were female. At baseline, median lipoprotein(a) concentration was 18·5 nmol/L (IQR 8·7-35·5) and mean carotid intima-media thickness was 0·4465 mm (SD 0·0496). During follow-up, higher lipoprotein(a) concentrations contributed significantly to progression of carotid intima-media thickness (β adjusted 0·0073 mm per 50 nmol/L increase in lipoprotein(a) [95% CI 0·0013-0·0132]; p=0·017).

INTERPRETATION

Our findings suggest that lipoprotein(a) concentrations contribute significantly to arterial wall thickening in children with familial hypercholesterolaemia who were followed-up until adulthood, suggesting that lipoprotein(a) is an independent and additional risk factor for early atherosclerosis in those already at increased risk. Lipoprotein(a) measurement in young patients with familial hypercholesterolaemia is crucial to identify those at potentially highest risk for cardiovascular disease.

FUNDING

Silence Therapeutics.

Current Management and Future Perspectives in the Treatment of Lp(a) with a Focus on the Prevention of Cardiovascular Diseases

Lipoprotein(a) [Lp(a)] is a lipid molecule with atherogenic, inflammatory, thrombotic, and antifibrinolytic effects, whose concentrations are predominantly genetically determined. The association between Lp(a) and cardiovascular diseases (CVDs) has been well-established in numerous studies, and the ability to measure Lp(a) levels is widely available in the community. As such, there has been increasing interest in Lp(a) as a therapeutic target for the prevention of CVD. The impact of the currently available lipid-modifying agents on Lp(a) is modest and heterogeneous, except for the monoclonal antibody proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i), which demonstrated a significant reduction in Lp(a) levels. However, the absolute reduction in Lp(a) to significantly decrease CVD outcomes has not been definitely established, and the magnitude of the effect of PCSK9i seems insufficient to directly reduce the Lp(a)-related CVD risk. Therefore, emerging therapies are being developed that specifically aim to lower Lp(a) levels and the risk of CVD, including RNA interference (RNAi) agents, which have the capacity for temporary and reversible downregulation of gene expression. This review article aims to summarize the effects of Lp(a) on CVD and to evaluate the available evidence on established and emerging therapies targeting Lp(a) levels, focusing on the potential reduction of CVD risk attributable to Lp(a) concentrations.

Evidence and Uncertainties on Lipoprotein(a) as a Marker of Cardiovascular Health Risk in Children and Adolescents

Lipoprotein(a) (Lp(a)) is made up of apoprotein(a) (apo(a)) and an LDL-like particle. The LPA gene encodes apo(a) and thus determines the characteristics and amount of apo(a) and Lp(a). The proportion of Lp(a) in each individual is genetically determined and is only minimally modifiable by the environment or diet. Lp(a) has important pro-atherosclerotic and pro-inflammatory effects. It has been hypothesized that Lp(a) also has pro-coagulant and antifibrinolytic actions. For these reasons, high Lp(a) values are an important independent risk factor for cardiovascular disease and calcific aortic valve stenosis. Numerous studies have been performed in adults about the pathophysiology and epidemiology of Lp(a) and research is under way for the development of drugs capable of reducing Lp(a) plasma values. Much less information is available regarding Lp(a) in children and adolescents. The present article reviews the evidence on this topic. The review addresses the issues of Lp(a) changes during growth, the correlation between Lp(a) values in children and those in their parents, and between Lp(a) levels in children, and the presence of cardiovascular disease in the family. Gaining information on these points is particularly important for deciding whether Lp(a) assay may be useful for defining the cardiovascular risk in children, in order to plan a prevention program early.

Frequent questions and responses on the 2022 lipoprotein(a) consensus statement of the European Atherosclerosis Society

In 2022, the European Atherosclerosis Society (EAS) published a new consensus statement on lipoprotein(a) [Lp(a)], summarizing current knowledge about its causal association with atherosclerotic cardiovascular disease (ASCVD) and aortic stenosis. One of the novelties of this statement is a new risk calculator showing how Lp(a) influences lifetime risk for ASCVD and that global risk may be underestimated substantially in individuals with high or very high Lp(a) concentration. The statement also provides practical advice on how knowledge about Lp(a) concentration can be used to modulate risk factor management, given that specific and highly effective mRNA-targeted Lp(a)-lowering therapies are still in clinical development. This advice counters the attitude: "Why should I measure Lp(a) if I can't lower it?". Subsequent to publication, questions have arisen relating to how the recommendations of this statement impact everyday clinical practice and ASCVD management. This review addresses 30 of the most frequently asked questions about Lp(a) epidemiology, its contribution to cardiovascular risk, Lp(a) measurement, risk factor management and existing therapeutic options.

Effects of Lipid-Modifying and Other Drugs on Lipoprotein(a) Levels-Potent Clinical Implications

The past few years have shown an ongoing interest in lipoprotein(a) (Lp(a)), a lipid molecule that has been proven to have atherogenic, thrombogenic, and inflammatory properties. Several lines of evidence, indeed, have demonstrated an increased risk of cardiovascular disease as well as calcific aortic valve stenosis in patients with elevated Lp(a) levels. Statins, the mainstay of lipid-lowering therapy, slightly increase Lp(a) levels, while most other lipid-modifying agents do not significantly alter Lp(a) concentrations, except for proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. The latter have been shown to reduce Lp(a) levels; however, the clinical significance of this effect has not been clearly elucidated. Of note, the pharmaceutical lowering of Lp(a) may be achieved with novel treatments specifically designed for this purpose (i.e., antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs)). Large clinical trials with cardiovascular outcomes with these agents are ongoing, and their results are eagerly awaited. Furthermore, several non-lipid-modifying drugs of various classes may influence Lp(a) concentrations. We have searched MEDLINE, EMBASE, and CENTRAL databases up to 28 January 2023 and summarized the effects of established and emerging lipid-modifying drugs and other medications on Lp(a) levels. We also discuss the potent clinical implications of these alterations.

Lipoprotein(a) levels in children with homozygous familial hypercholesterolaemia: A cross-sectional study

Homozygous familial hypercholesterolaemia (HoFH) is a life-threatening disorder characterized by extremely elevated low-density lipoprotein cholesterol (LDL-C) levels. Untreated, severe atherosclerotic cardiovascular disease (ASCVD), including aortic valve stenosis (AVS), may already occur in childhood. Another important genetic risk factor for ASCVD and AVS is elevated lipoprotein(a) [Lp(a)], which is highly prevalent in the general paediatric population. However, data on Lp(a) in children with HoFH are scarce. Therefore, we performed a cross-sectional study to evaluate Lp(a) levels in children with HoFH and compared them to children with heterozygous FH (HeFH) and unaffected children. Adjusted least-square mean (95% CI) Lp(a) levels in HoFH (n=29), HeFH (n=101) and unaffected children (n=102) were 18.7 (12.0-29.1), 15.3 (11.8-19.8) and 10.5 (8.3-13.2) mg/dL, respectively (p-for-trend=0.007). Lp(a) levels in children with HoFH were higher than in children with HeFH and in unaffected children. Given the very high ASCVD risk with HoFH, identifying other risk factors such as elevated Lp(a) in these children is important. Therefore, Lp(a) levels should be measured at least once in all children with HoFH.

Detection strategies for elevated lipoprotein(a): will implementation let the genie out of the bottle?

PURPOSE OF REVIEW

Elevated Lp(a) level is an important causal risk factor for atherosclerotic cardiovascular disease (ASCVD), principally coronary artery disease. Selective testing for Lp(a) is highly recommended in patients at intermediate and high risk for ASCVD. Lp(a) levels are predominantly genetically determined, and this has implications for cascade testing.

RECENT FINDINGS

Recent studies show that cascade testing is effective in identifying elevated Lp(a) in close relatives of probands with high Lp(a). Apart from selective testing and cascade testing as detection strategies, some recent guidelines recommend testing of Lp(a) in all adults at least once in their lifetime and various implementation strategies have been suggested.

SUMMARY

Hyper-Lp(a) is an important global health problem that can be easily detected. Hyper-Lp(a) meets all the criteria for universal screening except that there is not yet supportive evidence from clinical interventional trials showing a reduction of ASCVD events. The cost-effectiveness of the various detection and implementation strategies need to be further evaluated.

Association of the triglycerides and glucose index and the homeostatic model assessment of insulin resistance with lipoprotein(a), apolipoprotein AI, and apolipoprotein B concentrations in children with normal-weight

The aim of this study was to compare the association of the triglycerides and glucose (TyG) index and homeostatic model assessment of insulin resistance (HOMA-IR) with lipoprotein(a) (lp[a]), apolipoprotein AI (apoAI), and apoliprotein B (apoB) concentrations in children with normal-weight. Children with normal weight aged 6-10 years and Tanner 1 stage were included in a cross-sectional study. Underweight, overweight, obesity, smoking, alcohol intake, pregnancy, acute or chronic illnesses, and any kind of pharmacological treatment were exclusion criteria. According to the lp(a) levels, children were allocated into the groups with elevated concentrations and normal values. A total of 181 children with normal weight and an average age of 8.4 ± 1.4 years were enrolled in the study. The TyG index showed a positive correlation with lp(a) and apoB in the overall population (r = 0.161 and r = 0.351, respectively) and boys (r = 0.320 and r = 0.401, respectively), but only with apoB in the girls (r = 0.294); while the HOMA-IR had a positive correlation with lp(a) levels in the overall population (r = 0.213) and boys (r = 0.328). The linear regression analysis showed that the TyG index is associated with lp(a) and apoB in the overall population (B = 20.72; 95%CI 2.03-39.41 and B = 27.25; 95%CI 16.51-37.98, respectively) and boys (B = 40.19; 95%CI 14.50-65.7 and B = 29.60; 95%CI 15.03-44.17, respectively), but only with apoB in the girls (B = 24.22; 95%CI 7.90-40.53). The HOMA-IR is associated with lp(a) in the overall population (B = 5.37; 95%CI 1.74-9.00) and boys (B = 9.63; 95%CI 3.65-15.61).   Conclusion: The TyG index is associated with both lp(a) and apoB in children with normal-weight. What is Known: • The triglycerides and glucose index has been positively associated with an increased risk of cardiovascular disease in adults. What is New: • The triglycerides and glucose index is strongly associated with lipoprotein(a) and apolipoprotein B in children with normal-weight. • The triglycerides and glucose index may be a useful tool to identify cardiovascular risk in children with normal-weight.

How Genetic Variants in Children with Familial Hypercholesterolemia Not Only Guide Detection, but Also Treatment

Familial hypercholesterolemia (FH) is a hereditary disorder that causes severely elevated low-density lipoprotein (LDL-C) levels, which leads to an increased risk for premature cardiovascular disease. A variety of genetic variants can cause FH, namely variants in the genes for the LDL receptor (LDLR), apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and/or LDL-receptor adaptor protein 1 (LDLRAP1). Variants can exist in a heterozygous form (HeFH) or the more severe homozygous form (HoFH). If affected individuals are diagnosed early (through screening), they benefit tremendously from early initiation of lipid-lowering therapy, such as statins, and cardiovascular imaging to detect possible atherosclerosis. Over the last years, due to intensive research on the genetic basis of LDL-C metabolism, novel, promising therapies have been developed to reduce LDL-C levels and subsequently reduce cardiovascular risk. Results from studies on therapies focused on inhibiting PCSK9, a protein responsible for degradation of the LDLR, are impressive. As the effect of PCSK9 inhibitors (PCSK9-i) is dependent of residual LDLR activity, this medication is less potent in patients without functional LDLR (e.g., null/null variant). Novel therapies that are expected to become available in the near future focused on inhibition of another major regulatory protein in lipid metabolism (angiopoietin-like 3 (ANGPTL3)) might dramatically reduce the frequency of apheresis in children with HoFH, independently of their residual LDLR. At present, another independent risk factor for premature cardiovascular disease, elevated levels of lipoprotein(a) (Lp(a)), cannot be effectively treated with medication. Further understanding of the genetic basis of Lp(a) metabolism, however, offers a possibility for the development of novel therapies.

Australian Atherosclerosis Society Position Statement on Lipoprotein(a): Clinical and Implementation Recommendations

This position statement provides guidance to cardiologists and related specialists on the management of adult patients with elevated lipoprotein(a) [Lp(a)]. Elevated Lp(a) is an independent and causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve disease (CAVD). While circulating Lp(a) levels are largely determined by ancestry, they are also influenced by ethnicity, hormones, renal function, and acute inflammatory events, such that measurement should be done after accounting for these factors. Further, circulating Lp(a) concentrations should be estimated using an apo(a)-isoform independent assay that employs appropriate calibrators and reports the results in molar units (nmol/L). Selective screening strategies of high-risk patients are recommended, but universal screening of the population is currently not advised. Testing for elevated Lp(a) is recommended in all patients with premature ASCVD and those considered to be at intermediate-to-high risk of ASCVD. Elevated Lp(a) should be employed to assess and stratify risk and to enable a decision on initiation or intensification of preventative treatments, such as cholesterol lowering therapy. In adult patients with elevated Lp(a) at intermediate-to-high risk of ASCVD, absolute risk should be reduced by addressing all modifiable behavioural, lifestyle, psychosocial and clinical risk factors, including maximising cholesterol-lowering with statin and ezetimibe and, where appropriate, PCSK9 inhibitors. Apheresis should be considered in patients with progressive ASCVD. New ribonucleic acid (RNA)-based therapies which directly lower Lp(a) are undergoing clinical trials.

Differential effects of bariatric surgery and lifestyle interventions on plasma levels of Lp(a) and fatty acids

BACKGROUND

Limited evidence suggests that surgical and non-surgical obesity treatment differentially influence plasma Lipoprotein (a) [Lp(a)] levels. Further, a novel association between plasma arachidonic acid and Lp(a) has recently been shown, suggesting that fatty acids are a possible target to influence Lp(a). Here, the effects of bariatric surgery and lifestyle interventions on plasma levels of Lp(a) were compared, and it was examined whether the effects were mediated by changes in plasma fatty acid (FA) levels.

METHODS

The study includes two independent trials of patients with overweight or obesity. Trial 1: Two-armed intervention study including 82 patients who underwent a 7-week low energy diet (LED), followed by Roux-en-Y gastric bypass and 52-week follow-up (surgery-group), and 77 patients who underwent a 59-week energy restricted diet- and exercise-program (lifestyle-group). Trial 2: A clinical study including 134 patients who underwent a 20-week very-LED/LED (lifestyle-cohort).

RESULTS

In the surgery-group, Lp(a) levels [median (interquartile range)] tended to increase in the pre-surgical LED-phase [17(7-68)-21(7-81)nmol/L, P = 0.05], but decreased by 48% after surgery [21(7-81)-11(7-56)nmol/L, P < 0.001]. In the lifestyle-group and lifestyle-cohort, Lp(a) increased by 36%[14(7-77)-19(7-94)nmol/L, P < 0.001] and 14%[50(14-160)-57(19-208)nmol/L, P < 0.001], respectively. Changes in Lp(a) were independent of weight loss. Plasma levels of total saturated FAs remained unchanged after surgery, but decreased after lifestyle interventions. Arachidonic acid and total n-3 FAs decreased after surgery, but increased after lifestyle interventions. Plasma FAs did not mediate the effects on Lp(a).

CONCLUSION

Bariatric surgery reduced, whereas lifestyle interventions increased plasma Lp(a), independent of weight loss. The interventions differentially influenced changes in plasma FAs, but these changes did not mediate changes in Lp(a).

TRIAL REGISTRATION

Trial 1: Clinicaltrials.gov NCT00626964. Trial 2: Netherlands Trial Register NL2140 (NTR2264).

New Horizons: Revival of Lipoprotein (a) as a Risk Factor for Cardiovascular Disease

The status of lipoprotein (a) [Lp(a)] as a cardiovascular risk factor has been resurrected by advances in genetics. Mendelian randomization studies show a causal link of Lp(a) with coronary artery disease (CAD), peripheral artery disease (PAD), and calcific aortic valve stenosis (CAVS). The genetics of Lp(a) is complex and extends beyond the kringle-IV type 2, as it is also dependent on ancestry. The plasma concentration of Lp(a) is determined by the hepatic production of apolipoprotein(a) [apo(a)] component of Lp(a), supporting the use of nucleic acids that inhibit the messenger RNA (mRNA) gene transcript for apo(a). Analytical barriers to measurement of Lp(a) are being addressed using isoform independent assays and a traceable standard. The association of Lp(a) and atherosclerotic cardiovascular disease is higher for myocardial infarction than PAD and CAVS. Increased risk of type 2 diabetes mellitus associated with low Lp(a) levels is perplexing and requires further investigation. The greatest advancement in Lp(a)-lowering therapies is based on using RNA therapeutics that are now being investigated in clinical trials. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition lowers Lp(a) modestly, but whether cardiovascular benefit is independent of low-density lipoprotein lowering remains unclear. Opportunistic and selective testing for Lp(a) is supported by moderate evidence, with the case for universal screening premature. Modification of behavioral and clinical risk factors may be targeted to mitigate Lp(a)-mediated risk of cardiovascular disease. Clinical practice guidelines have been developed to address gaps in care of high Lp(a), but full implementation awaits the findings of clinical outcome trials using RNA-directed therapies currently underway.

Lipoprotein(a) levels in children with suspected familial hypercholesterolaemia: a cross-sectional study

AIMS

Familial hypercholesterolaemia (FH) predisposes children to the early initiation of atherosclerosis and is preferably diagnosed by DNA analysis. Yet, in many children with a clinical presentation of FH, no mutation is found. Adult data show that high levels of lipoprotein(a) [Lp(a)] may underlie a clinical presentation of FH, as the cholesterol content of Lp(a) is included in conventional LDL cholesterol measurements. As this is limited to adult data, Lp(a) levels in children with and without (clinical) FH were evaluated.

METHODS AND RESULTS

Children were eligible if they visited the paediatric lipid clinic (1989-2020) and if Lp(a) measurement and DNA analysis were performed. In total, 2721 children (mean age: 10.3 years) were included and divided into four groups: 1931 children with definite FH (mutation detected), 290 unaffected siblings/normolipidaemic controls (mutation excluded), 108 children with probable FH (clinical presentation, mutation not detected), and 392 children with probable non-FH (no clinical presentation, mutation not excluded). In children with probable FH, 32% were found to have high Lp(a) [geometric mean (95% confidence interval) of 15.9 (12.3-20.6) mg/dL] compared with 10 and 10% [geometric means (95% confidence interval) of 11.5 (10.9-12.1) mg/dL and 9.8 (8.4-11.3) mg/dL] in children with definite FH (P = 0.017) and unaffected siblings (P = 0.002), respectively.

CONCLUSION

Lp(a) was significantly higher and more frequently elevated in children with probable FH compared with children with definite FH and unaffected siblings, suggesting that high Lp(a) may underlie the clinical presentation of FH when no FH-causing mutation is found. Performing both DNA analysis and measuring Lp(a) in all children suspected of FH is recommended to assess possible LDL cholesterol overestimation related to increased Lp(a).

Pharmacotherapy for children with elevated levels of lipoprotein(a): future directions

INTRODUCTION

Elevated lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD). With the advent of the antisense oligonucleotides (ASOs) and small interfering RNAs (siRNAs) targeted at LPA, the gene encoding apolipoprotein(a), that are highly effective for lowering Lp(a) levels, this risk factor might be managed in the near future. Given that Lp(a) levels are mostly genetically determined and once elevated, present from early age, we have evaluated future directions for the treatment of children with high Lp(a) levels.

AREAS COVERED

In the current review, we discuss different pharmacological treatments in clinical development and provide an in-depth overview of the effects of ASOs and siRNAs targeted at LPA.

EXPERT OPINION

Since high Lp(a) is an important risk factor for ASCVD and given the promising effects of both ASOs and siRNAs targeted at apo(a), there is an urgent need for well-designed prospective studies to assess the impact of elevated Lp(a) in childhood. If the Lp(a)-hypothesis is confirmed in adults, and also in children, the rationale might arise for treating children with high Lp(a) levels. However, we feel that this should be limited to children with the highest cardiovascular risk including familial hypercholesterolemia and potentially pediatric stroke.

Lipoprotein(a) in atherosclerotic cardiovascular disease and aortic stenosis: a European Atherosclerosis Society consensus statement

This 2022 European Atherosclerosis Society lipoprotein(a) [Lp(a)] consensus statement updates evidence for the role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis, provides clinical guidance for testing and treating elevated Lp(a) levels, and considers its inclusion in global risk estimation. Epidemiologic and genetic studies involving hundreds of thousands of individuals strongly support a causal and continuous association between Lp(a) concentration and cardiovascular outcomes in different ethnicities; elevated Lp(a) is a risk factor even at very low levels of low-density lipoprotein cholesterol. High Lp(a) is associated with both microcalcification and macrocalcification of the aortic valve. Current findings do not support Lp(a) as a risk factor for venous thrombotic events and impaired fibrinolysis. Very low Lp(a) levels may associate with increased risk of diabetes mellitus meriting further study. Lp(a) has pro-inflammatory and pro-atherosclerotic properties, which may partly relate to the oxidized phospholipids carried by Lp(a). This panel recommends testing Lp(a) concentration at least once in adults; cascade testing has potential value in familial hypercholesterolaemia, or with family or personal history of (very) high Lp(a) or premature ASCVD. Without specific Lp(a)-lowering therapies, early intensive risk factor management is recommended, targeted according to global cardiovascular risk and Lp(a) level. Lipoprotein apheresis is an option for very high Lp(a) with progressive cardiovascular disease despite optimal management of risk factors. In conclusion, this statement reinforces evidence for Lp(a) as a causal risk factor for cardiovascular outcomes. Trials of specific Lp(a)-lowering treatments are critical to confirm clinical benefit for cardiovascular disease and aortic valve stenosis.

Triglyceride Metabolism Modifies Lipoprotein(a) Plasma Concentration

BACKGROUND

Lipoprotein(a) (Lp(a)) is a significant cardiovascular risk factor. Knowing the mechanisms that regulate its concentration can facilitate the development of Lp(a)-lowering drugs. This study analyzes the relationship between triglycerides (TGs) and Lp(a) concentrations, cross-sectionally and longitudinally, and the influence of the number and composition of TG-rich lipoproteins, and the APOE genotype.

METHODS

Data from Aragon Workers Health Study (AWHS) (n = 5467), National Health and Nutrition Examination Survey III phase 2 (n = 3860), and Hospital Universitario Miguel Servet (HUMS) (n = 2079) were used for cross-sectional TG and Lp(a) relationship. Lp(a) intrasubject variation was studied in AWHS participants and HUMS patients with repeated measurements. TG-rich lipoproteins were quantified by nuclear magnetic resonance in a subsample from AWHS. Apolipoproteins B and E were quantified by Luminex in very low-density lipoprotein (VLDL) isolated by ultracentrifugation, from HUMS samples. APOE genotyping was carried in AWHS and HUMS participants. Regression models adjusted for age and sex were used to study the association.

RESULTS

The 3 studies showed an inverse relationship between TG and Lp(a). Increased VLDL number, size, and TG content were associated with significantly lower Lp(a). There was an inverse association between the apoE concentration in VLDL and Lp(a). No significant association was observed for apolipoprotein (apo)B. Subjects carrying the apoE2/E2 genotype had significantly lower levels of Lp(a).

CONCLUSION

Our results show an inverse relationship Lp(a)-TG. Subjects with larger VLDL size have lower Lp(a), and lower values of Lp(a) were present in patients with apoE-rich VLDL and apoE2/E2 subjects. Our results suggest that bigger VLDLs and VLDLs enriched in apoE are inversely involved in Lp(a) plasma concentration.

Lipoprotein(a) in the Korean Pediatric Population Visiting Local Clinics and Hospitals

In this paper we investigate serum lipoprotein(a), an independent risk factor for cardiovascular disease in the Korean pediatric population. Visiting local clinics and hospitals, 600 lipoprotein(a) tests were performed on 416 Korean children and adolescents (124 boys and 292 girls), with a median age of 11.1 years (interquartile range, IQR, 9.8–13.9). The median lipoprotein(a) level was 21.5 nmol/L (IQR, 8.2–51.7). Among the 416 patients, the 90th percentile value of the initial lipoprotein(a) measurement was 107.8 nmol/L. The proportion of patients with lipoprotein(a) ≥ 100 nmol/L was 11.3%. The lipoprotein(a) level and the proportion of patients with lipoprotein(a) ≥ 100 nmol/L were not significantly different among sex, or age group. Among the 416 patients, 122 (29.3%, 21 boys and 101 girls) underwent at least two follow-up lipoprotein(a) measurements. The median follow-up period was 6.7 months (IQR, 5.5–11.8). The median lipoprotein(a) level across the 122 patients was 25 nmol/L (IQR 10.0–72.0). Among those patients, seven (5.7%) experienced an increase in serum lipoprotein(a) to ≥100 nmol/L during follow-up measurements. Further studies are needed in the Korean pediatric population in order to clarify the clinical significance of this change long-term.

Lipoprotein(a) measurement issues: Are we making a mountain out of a molehill?

Lipoprotein(a) [Lp(a)] became besides LDL cholesterol one of the most attractive targets for intervention in cardiovascular disease. Strong genetic evidence supports the causal association between high Lp(a) concentrations and cardiovascular outcomes. Since specific Lp(a)-lowering therapies are under clinical investigation, the interest in measuring Lp(a) has markedly increased. However, the special structure of the lead protein component of Lp(a), named apolipoprotein(a), creates difficulties for an accurate measurement of Lp(a). A highly homologous repetitive structure, called kringle IV repeat with up to more the 40 repeats, causes a highly polymorphic protein. Antibodies raised against apolipoprotein(a) are mostly directed against the repetitive structure of this protein, which complicates the measurement of Lp(a) in molar terms. Both measurements in mass (mg/dL) and molar terms (nmol/L) are described and a conversion from one into the another unit is only approximately possible. Working groups for standardization of Lp(a) measurements are going to prepare widely available and improved reference materials, which will be a major step for the measurement of Lp(a). This review discusses many aspects of the difficulties in measuring Lp(a). It tries to distinguish between academic and practical concerns and warns to make a mountain out of a molehill, which does no longer allow to see the patient behind that mountain by simply staring at the laboratory issues. On the other hand, the calibration of some assays raises major concerns, which are anything else but a molehill. This should be kept in mind and we should start measuring Lp(a) with the aim of a better risk stratification for the patient and to identify those patients who might be in urgent need for a specific Lp(a)-lowering therapy as soon as it becomes available.

Familial Hypercholesterolemia and Elevated Lipoprotein(a): Cascade Testing and Other Implications for Contextual Models of Care

Elevated lipoprotein(a) [Lp(a)], a predominantly genetic disorder, is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valvular disease, particularly in patients with familial hypercholesterolemia (FH), a Tier I genomic condition. The combination from birth of the cumulative exposure to elevated plasma concentrations of both Lp(a) and low-density lipoprotein is particularly detrimental and explains the enhanced morbidity and mortality risk observed in patients with both conditions. An excellent opportunity to identify at-risk patients with hyper-Lp(a) at increased risk of ASCVD is to test for hyper-Lp(a) during cascade testing for FH. With probands having FH and hyper-Lp(a), the yield of detection of hyper-Lp(a) is 1 individual for every 2.1-2.4 relatives tested, whereas the yield of detection of both conditions is 1 individual for every 3-3.4 relatives tested. In this article, we discuss the incorporation of assessment of Lp(a) in the cascade testing in FH as a feasible and crucial part of models of care for FH. We also propose a simple management tool to help physicians identify and manage elevated Lp(a) in FH, with implications for the care of Lp(a) beyond FH, noting that the clinical use of RNA therapeutics for specifically targeting the overproduction of Lp(a) in at risk patients is still under investigation.