Lipoprotein(a) Levels, Genotype, and Incident Aortic Valve Stenosis: A Prospective Mendelian Randomization Study and Replication in a Case–Control Cohort

Current Management and Therapy of Severe Aortic Stenosis and Future Perspective

Intervention for severe aortic stenosis (AS) has dramatically progressed since the introduction of transcatheter aortic valve replacement (TAVR). Decades ago, controversies existed regarding comparing clinical outcomes between TAVR and surgical aortic valve replacement (SAVR) in various risk profiles. Recently, we discussed the durability of transcatheter heart valves and their lifetime management after aortic valve replacement (AVR). Regarding the management of AS, we discuss the appropriate timing of intervention for severe aortic stenosis, especially in asymptomatic patients. In spite of dramatic progression of intervention for AS, there are no established medications available to prevent or slow the progression of AS at present. Basic research and genome studies have suggested several targets associated with the progression of aortic valve calcification. Randomized controlled trials evaluating the efficacy of medications to prevent AS progression are ongoing, which might lead to new strategies for AS management. In this review, we summarize the current management of AS and the drugs expected to prevent the progression of AS.

Oral agents for lowering lipoprotein(a)

PURPOSE OF REVIEW

To review the development of oral agents to lower Lp(a) levels as an approach to reducing cardiovascular risk, with a focus on recent advances in the field.

RECENT FINDINGS

Extensive evidence implicates Lp(a) in the causal pathway of atherosclerotic cardiovascular disease and calcific aortic stenosis. There are currently no therapies approved for lowering of Lp(a). The majority of recent therapeutic advances have focused on development of injectable agents that target RNA and inhibit synthesis of apo(a). Muvalaplin is the first, orally administered, small molecule inhibitor of Lp(a), which acts by disrupting binding of apo(a) and apoB, in clinical development. Nonhuman primate and early human studies have demonstrated the ability of muvalaplin to produce dose-dependent lowering of Lp(a). Ongoing clinical trials will evaluate the impact of muvalaplin in high cardiovascular risk and will ultimately need to determine whether this strategy lowers the rate of cardiovascular events.

SUMMARY

Muvalaplin is the first oral agent, developed to lower Lp(a) levels. The ability of muvalaplin to reduce cardiovascular risk remains to be investigated, in order to determine whether it will be a useful agent for the prevention of cardiovascular disease.

Unmet needs and knowledge gaps in aortic stenosis: A position paper from the Heart Valve Council of the French Society of Cardiology

Nowadays, valvular heart disease remains a significant challenge among cardiovascular diseases, affecting millions of people worldwide and exerting substantial pressure on healthcare systems. Within the spectrum of valvular heart disease, aortic stenosis is the most common valvular lesion in developed countries. Despite notable advances in understanding its pathophysiological processes, improved cardiovascular imaging techniques and expanding therapeutic options in recent years, there are still unmet needs and knowledge gaps regarding aortic stenosis pathophysiology, severity assessment, management and decision-making strategy. This review, prepared on behalf of the Heart Valve Council of the French Society of Cardiology, describes these gaps and future research perspectives to improve the outcome of patients with aortic stenosis.

Lipoprotein(a) and Calcific Aortic Valve Stenosis Progression: A Systematic Review and Meta-Analysis

Importance

There are currently no pharmacological treatments available to slow hemodynamic progression of aortic stenosis. Plasma lipoprotein(a) concentrations predict incident aortic stenosis but its association with hemodynamic progression is controversial.

Objective

To determine the association between plasma lipoprotein(a) concentrations and hemodynamic progression in patients with aortic stenosis.

Design, Settings and Participants

The study included patients with aortic stenosis from 5 longitudinal clinical studies conducted from March 2001 to March 2023 in Canada and the UK. Of 757 total patients, data on plasma lipoprotein(a) concentrations and rates of hemodynamic progression assessed by echocardiography were available for 710, who were included in this analysis. Data were analyzed from March 2023 to April 2024.

Exposure

Cohort-specific plasma lipoprotein(a) concentration tertiles.

Main Outcomes and Measures

Hemodynamic aortic stenosis progression on echocardiography as assessed by annualized change in peak aortic jet velocity, mean transvalvular gradient, and aortic valve area.

Results

Among the included patients, 497 (70%) were male and 213 (30%) were female. The mean (SD) age was 65.2 (13.1) years. Patients in the top lipoprotein(a) tertile demonstrated 41% (estimate, 1.41; 95% CI, 1.13-1.75) faster progression of peak aortic jet velocity and 57% (estimate, 1.57; 95% CI, 1.18-2.10) faster progression of mean transvalvular gradient than patients in the bottom tertile. There was no evidence of heterogeneity across the individual cohorts. Progression of aortic valve area was comparable between groups (estimate, 1.23; 95% CI, 0.71-2.12). Similar results were observed when plasma lipoprotein(a) concentrations were treated as a continuous variable.

Conclusions and Relevance

In this study, higher plasma lipoprotein(a) concentrations were associated with faster rates of hemodynamic progression in patients with aortic stenosis. Lowering plasma lipoprotein(a) concentrations warrants further investigation in the prevention and treatment of aortic stenosis.

Association between lipoprotein(a), LPA genetic risk score, aortic valve disease, and subsequent major adverse cardiovascular events

AIMS

Cohort studies have demonstrated associations between calcific aortic valve disease (CAVD) and Lp(a). As Lp(a) is almost entirely genetically determined, in this study, we aim to determine whether Lp(a), when predicted from genetic data, is associated with CAVD and major adverse cardiovascular events (MACEs).

METHODS AND RESULTS

Patients undergoing coronary angiography between January 2012 and May 2013 were invited to participate in the study. Of 752 analysable participants, 446 had their Lp(a) measured and 703 had a calculable LPA genetic risk score (GRS). The primary outcomes were the presence of CAVD at baseline and MACE over a 7-year follow-up. The GRS explained 45% of variation in Lp(a). After adjustment for cardiac risk factors and coronary artery disease (CAD), the odds of CAVD increased with increasing Lp(a) [odds ratio (OR) 1.039 per 10-unit increase, 95% confidence interval (CI) 1.022-1.057, P < 0.001] and GRS (OR 1.054 per 10-unit increase, 95% CI 1.024-1.086; P < 0.001). Lipoprotein(a) and the GRS as continuous variables were not associated with subsequent MACEs. A dichotomized GRS (>54) was associated with MACE, but this relationship became non-significant when CAD classification was added into the model (OR 1.333, 95% CI 0.927-1.912; P = 0.12).

CONCLUSION

An LPA GRS can explain 45% of variation in Lp(a) levels, and both Lp(a) and the GRS are associated with CAVD. An elevated GRS is associated with future cardiac events in a secondary risk setting, but, if the CAD status is known, it does not provide additional prognostic information.

Lysophosphatidic acid metabolism and signaling in heart disease

Lysophosphatidic acid (LPA) is a bioactive lipid that is mainly produced by the secreted lysophospholipase D, autotaxin (ATX), and signals through at least six G protein-coupled receptors (LPA1-6). Extracellular LPA is degraded through lipid phosphate phosphatases (LPP1, LPP2, and LPP3) at the plasmamembrane, terminating LPA receptor signaling. The ATX-LPA-LPP3 pathway is critically involved in a wide range of physiological processes, including cell survival, migration, proliferation, angiogenesis, and organismal development. Similarly, dysregulation of this pathway has been linked to many pathological processes, including cardiovascular disease. This review summarizes and interprets current literature examining the regulation and role of the ATX-LPA-LPP3 axis in heart disease. Specifically, the contribution of altered LPA metabolism via ATX and LPP3 and resulting changes to LPA receptor signaling in obesity cardiomyopathy, cardiac mitochondrial dysfunction, myocardial infarction/ischemia-reperfusion injury, hypertrophic cardiomyopathy, and aortic valve stenosis is discussed.

Consensus on lipoprotein(a) of the Spanish Society of Arteriosclerosis. Literature review and recommendations for clinical practice

The irruption of lipoprotein(a) (Lp(a)) in the study of cardiovascular risk factors is perhaps, together with the discovery and use of proprotein convertase subtilisin/kexin type 9 (iPCSK9) inhibitor drugs, the greatest novelty in the field for decades. Lp(a) concentration (especially very high levels) has an undeniable association with certain cardiovascular complications, such as atherosclerotic vascular disease (AVD) and aortic stenosis. However, there are several current limitations to both establishing epidemiological associations and specific pharmacological treatment. Firstly, the measurement of Lp(a) is highly dependent on the test used, mainly because of the characteristics of the molecule. Secondly, Lp(a) concentration is more than 80% genetically determined, so that, unlike other cardiovascular risk factors, it cannot be regulated by lifestyle changes. Finally, although there are many promising clinical trials with specific drugs to reduce Lp(a), currently only iPCSK9 (limited for use because of its cost) significantly reduces Lp(a). However, and in line with other scientific societies, the SEA considers that, with the aim of increasing knowledge about the contribution of Lp(a) to cardiovascular risk, it is relevant to produce a document containing the current status of the subject, recommendations for the control of global cardiovascular risk in people with elevated Lp(a) and recommendations on the therapeutic approach to patients with elevated Lp(a).

Therapeutic Potential of Lipoprotein(a) Inhibitors

Increasing evidence has implicated lipoprotein(a) [Lp(a)] in the causality of atherosclerosis and calcific aortic stenosis. This has stimulated immense interest in developing novel approaches to integrating Lp(a) into the setting of cardiovascular prevention. Current guidelines advocate universal measurement of Lp(a) levels, with the potential to influence cardiovascular risk assessment and triage of higher-risk patients to use of more intensive preventive therapies. In parallel, considerable activity has been undertaken to develop novel therapeutics with the potential to achieve selective and substantial reductions in Lp(a) levels. Early studies of antisense oligonucleotides (e.g., mipomersen, pelacarsen), RNA interference (e.g., olpasiran, zerlasiran, lepodisiran) and small molecule inhibitors (e.g., muvalaplin) have demonstrated effective Lp(a) lowering and good tolerability. These agents are moving forward in clinical development, in order to determine whether Lp(a) lowering reduces cardiovascular risk. The results of these studies have the potential to transform our approach to the prevention of cardiovascular disease.

Identifying People at High Risk for Severe Aortic Stenosis: Aortic Valve Calcium Versus Lipoprotein(a) and Low-Density Lipoprotein Cholesterol

BACKGROUND

Aortic valve calcification (AVC), Lp(a) [lipoprotein(a)], and low-density lipoprotein cholesterol (LDL-C) are associated with severe aortic stenosis (AS). We aimed to determine which of these risk factors were most strongly associated with the risk of incident severe AS.

METHODS

A total of 6792 participants from the MESA study (Multi-Ethnic Study of Atherosclerosis) had computed tomography-quantified AVC, Lp(a), and LDL-C values at MESA visit 1 (2000-2002). We calculated the absolute event rate of incident adjudicated severe AS per 1000 person-years and performed multivariable adjusted Cox proportional hazards regression.

RESULTS

The mean age was 62 years old, and 47% were women. Over a median 16.7-year follow-up, the rate of incident severe AS increased exponentially with higher AVC, regardless of Lp(a) or LDL-C values. Participants with AVC=0 had a very low rate of severe AS even with elevated Lp(a) ≥50 mg/dL (<0.1/1000 person-years) or LDL-C ≥130 mg/dL (0.1/1000 person-years). AVC >0 was strongly associated with severe AS when Lp(a) <50 mg/dL hazard ratio (HR) of 33.8 (95% CI, 16.4-70.0) or ≥50 mg/dL HR of 61.5 (95% CI, 7.7-494.2) and when LDL-C <130 mg/dL HR of 31.1 (95% CI, 14.4-67.1) or ≥130 mg/dL HR of 50.2 (95% CI, 13.2-191.9).

CONCLUSIONS

AVC better identifies people at high risk for severe AS compared with Lp(a) or LDL-C, and people with AVC=0 have a very low long-term rate of severe AS regardless of Lp(a) or LDL-C level. These results suggest AVC should be the preferred prognostic risk marker to identify patients at high risk for severe AS, which may help inform participant selection for future trials testing novel strategies to prevent severe AS.

Lipoprotein(a): Emerging insights and therapeutics

The strong association between lipoprotein (a) [Lp(a)] and atherosclerotic cardiovascular disease has led to considerations of Lp(a) being a potential target for mitigating residual cardiovascular risk. While approximately 20 % of the population has an Lp(a) level greater than 50 mg/dL, there are no currently available pharmacological lipid-lowering therapies that have demonstrated substantial reduction in Lp(a). Novel therapies to lower Lp(a) include antisense oligonucleotides and small-interfering ribonucleic acid molecules and have shown promising results in phase 2 trials. Phase 3 trials are currently underway and will test the causal relationship between Lp(a) and ASCVD and whether lowering Lp(a) reduces cardiovascular outcomes. In this review, we summarize emerging insights related to Lp(a)'s role as a risk-enhancing factor for ASCVD, association with calcific aortic stenosis, effects of existing therapies on Lp(a) levels, and variations amongst patient populations. The evolving therapeutic landscape of emerging therapeutics is further discussed.

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).

Functional interrogation of cellular Lp(a) uptake by genome-scale CRISPR screening

An elevated level of lipoprotein(a), or Lp(a), in the bloodstream has been causally linked to the development of atherosclerotic cardiovascular disease and calcific aortic valve stenosis. Steady state levels of circulating lipoproteins are modulated by their rate of clearance, but the identity of the Lp(a) uptake receptor(s) has been controversial. In this study, we performed a genome-scale CRISPR screen to functionally interrogate all potential Lp(a) uptake regulators in HuH7 cells. Strikingly, the top positive and negative regulators of Lp(a) uptake in our screen were LDLR and MYLIP, encoding the LDL receptor and its ubiquitin ligase IDOL, respectively. We also found a significant correlation for other genes with established roles in LDLR regulation. No other gene products, including those previously proposed as Lp(a) receptors, exhibited a significant effect on Lp(a) uptake in our screen. We validated the functional influence of LDLR expression on HuH7 Lp(a) uptake, confirmed in vitro binding between the LDLR extracellular domain and purified Lp(a), and detected an association between loss-of-function LDLR variants and increased circulating Lp(a) levels in the UK Biobank cohort. Together, our findings support a central role for the LDL receptor in mediating Lp(a) uptake by hepatocytes.

All we need to know about lipoprotein(a)

Lipoprotein(a) [Lp(a)], a genetically determined macromolecular complex, is independently and causally associated with atherosclerotic cardiovascular disease (ASCVD) and calcific aortic stenosis via proposed proinflammatory, prothrombotic, and proatherogenic mechanisms. While Lp(a) measurement standardization issues are being resolved, several guidelines now support testing Lp(a) at least once in each adult's lifetime for ASCVD risk prediction which can foster implementation of more aggressive primary or secondary prevention therapies. Currently, there are several emerging targeted Lp(a) lowering therapies in active clinical investigation for safety and cardiovascular benefit among both primary and secondary prevention populations. First degree relatives of patients with high Lp(a) should be encouraged to undergo cascade screening. Primary prevention patients with high Lp(a) should consider obtaining a coronary calcium score for further risk estimation and to guide further ASCVD risk factor management including consideration of low dose aspirin therapy. Secondary prevention patients with high Lp(a) levels should consider adding PCSK9 inhibition to statin therapy.

Drug target Mendelian randomization supports apolipoprotein C3-lowering for lipoprotein-lipid levels reductions and cardiovascular diseases prevention

BACKGROUND AND AIMS

Inhibitors of apolipoprotein C-III (apoC3) are currently approved for the reduction of triglyceride levels in patients with Familial Chylomicronemia Syndrome. We used drug target Mendelian randomization (MR) to assess the effect of genetically predicted decrease in apoC3 blood protein levels on cardiometabolic traits and diseases.

METHODS

We quantified lifelong reductions in apoC3 blood levels by selecting all genome wide significant and independent (r2<0.1) single nucleotide polymorphisms (SNPs) in the APOC3 gene region ±1 Mb, from three genome-wide association studies (GWAS) of apoC3 blood protein levels (deCODE, n = 35,378, Fenland, n = 10,708 and ARIC, n = 7213). We included the largest GWASes on 18 cardiometabolic traits and 9 cardiometabolic diseases as study outcomes.

RESULTS

A one standard deviation lowering in apoC3 blood protein levels was associated with lower triglycerides, apolipoprotein B, low-density lipoprotein cholesterol, alanine aminotransferase, and glomerular filtration rate as well as higher high-density lipoprotein cholesterol levels. ApoC3 lowering was also associated with lower risk of acute pancreatitis (odds ratio [OR] = 0.91 95% CI = 0.82 to 1.00), aortic stenosis (OR = 0.82 95% CI = 0.73 to 0.93), and coronary artery disease (OR = 0.86 95% CI = 0.80 to 0.93), and was associated with increased parental lifespan (0.06 95% CI = 0.03-0.09 years). These results were concordant across robust MR methods, the three protein datasets and upon adjustment for APOA1, APOA4 and APOA5 using a multivariable MR framework.

CONCLUSIONS

These results provide evidence that apoC3 lowering could result in widespread benefits for cardiometabolic health and encourage the launch of trials on apoC3 inhibition for coronary artery disease prevention.

Application of improved GalNAc conjugation in development of cost-effective siRNA therapies targeting cardiovascular diseases

N-Acetylgalactosamine (GalNAc)-conjugated small interfering RNA (siRNA) therapies have received approval for treating both orphan and prevalent diseases. To improve in vivo efficacy and streamline the chemical synthesis process for efficient and cost-effective manufacturing, we conducted this study to identify better designs of GalNAc-siRNA conjugates for therapeutic development. Here, we present data on redesigned GalNAc-based ligands conjugated with siRNAs against angiopoietin-like 3 (ANGPTL3) and lipoprotein (a) (Lp(a)), two target molecules with the potential to address large unmet medical needs in atherosclerotic cardiovascular diseases. By attaching a novel pyran-derived scaffold to serial monovalent GalNAc units before solid-phase oligonucleotide synthesis, we achieved increased GalNAc-siRNA production efficiency with fewer synthesis steps compared to the standard triantennary GalNAc construct L96. The improved GalNAc-siRNA conjugates demonstrated equivalent or superior in vivo efficacy compared to triantennary GalNAc-conjugated siRNAs.

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.

Lipoprotein(a) Is Markedly More Atherogenic Than LDL: An Apolipoprotein B-Based Genetic Analysis

BACKGROUND

Lipoprotein(a) (Lp(a)) is recognized as a causal factor for coronary heart disease (CHD) but its atherogenicity relative to that of low-density lipoprotein (LDL) on a per-particle basis is indeterminate.

OBJECTIVES

The authors addressed this issue in a genetic analysis based on the fact that Lp(a) and LDL both contain 1 apolipoprotein B (apoB) per particle.

METHODS

Genome-wide association studies using the UK Biobank population identified 2 clusters of single nucleotide polymorphisms: one comprising 107 variants linked to Lp(a) mass concentration, the other with 143 variants linked to LDL concentration. In these Lp(a) and LDL clusters, the relationship of genetically predicted variation in apoB with CHD risk was assessed.

RESULTS

The Mendelian randomization-derived OR for CHD for a 50 nmol/L higher Lp(a)-apoB was 1.28 (95% CI: 1.24-1.33) compared with 1.04 (95% CI: 1.03-1.05) for the same increment in LDL-apoB. Likewise, use of polygenic scores to rank subjects according to difference in Lp(a)-apoB vs difference in LDL-apoB revealed a greater HR for CHD per 50 nmol/L apoB for the Lp(a) cluster (1.47; 95% CI: 1.36-1.58) compared with the LDL cluster (1.04; 95% CI: 1.02-1.05). From these data, we estimate that the atherogenicity of Lp(a) is approximately 6-fold (point estimate of 6.6; 95% CI: 5.1-8.8) greater than that of LDL on a per-particle basis.

CONCLUSIONS

We conclude that the atherogenicity of Lp(a) (CHD risk quotient per unit increase in particle number) is substantially greater than that of LDL. Therefore, Lp(a) represents a key target for drug-based intervention in a significant proportion of the at-risk population.

Lp(a) and risk of cardiovascular disease - A review of existing evidence and emerging concepts

Cardiovascular disease (CVD) remains the leading cause of death among adults in the United States. There has been significant advancement in the diagnosis and treatment of atherosclerotic cardiovascular disease (ASCVD) and its underlying risk factors. In certain populations, there remains a significant residual risk despite adequate lowering of low-density lipoprotein cholesterol (LDL-C) and control of traditional risk factors. This has led to an interest in research to identify additional risk factors that contribute to atherosclerotic cardiovascular disease. Elevated lipoprotein (a) [Lp(a)] has been identified as an independent risk factor contributing to an increased risk for CVD. There are also ethnic and racial disparities in Lp(a) inheritance that need to be understood. This paper reviews the current literature on lipoprotein a, proposed mechanisms of actions for cardiovascular disease, recommendations for testing, and the current and emerging therapies for lowering Lp(a).

Relationship between lipoprotein(a) and whole blood reducing viscosity: A cross-sectional study

Lipoprotein(a) [Lp(a)] has been confirmed as a causal risk factor of atherosclerotic cardiovascular disease, but its role on circulation is not completely clear and is still being explored. Therefore, this study attempts to explore the relationship between Lp(a) and whole blood reducing viscosity (WBRV), to better understand the role of Lp(a) in circulatory and cardiovascular diseases. We retrospectively analyzed the data of consecutive subjects in the physical examination center of the Affiliated Hospital of Ningbo University Medical College from January 2022 to May 2022. Pearson or spearman correlation analysis was used to test the statistical relationship between 2 continuous variables according to whether they are normal; 131 participants were retrospectively enrolled in this study. The low-density lipoprotein concentration was associated with whole blood viscosity at low-shear (R = 0.220, P = .012), middle-shear (R = 0.226, P = .01), and high-shear viscosity (R = 0.212, P = .015), as well as plasma viscosity (RS = 0.207, P = .018). Lp(a) was not associated with whole blood viscosity at low, middle, and high shear rates, but was associated with WBRV at low shear (RS = 0.204, P = .019) and middle shear rates (RS = 0.197, P = .024). Lp(a) is associated with high WBRV, which may impart more insights into the role of Lp(a) in cardiovascular disease.

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).

Lp(a) in the Pathogenesis of Aortic Stenosis and Approach to Therapy with Antisense Oligonucleotides or Short Interfering RNA

To date, no medical therapy can slow the progression of aortic stenosis. Fibrocalcific stenosis is the most frequent form in the general population and affects about 6% of the elderly population. Over the years, diagnosis has evolved thanks to echocardiography and computed tomography assessments. The application of artificial intelligence to electrocardiography could further implement early diagnosis. Patients with severe aortic stenosis, especially symptomatic patients, have valve repair as their only therapeutic option by surgical or percutaneous technique (TAVI). The discovery that the pathogenetic mechanism of aortic stenosis is similar to the atherosclerosis process has made it possible to evaluate the hypothesis of medical therapy for aortic stenosis. Several drugs have been tested to reduce low-density lipoprotein (LDL) and lipoprotein(a) (Lp(a)) levels, inflammation, and calcification. The Proprotein Convertase Subtilisin/Kexin type 9 inhibitors (PCSK9-i) could decrease the progression of aortic stenosis and the requirement for valve implantation. Great interest is related to circulating Lp(a) levels as causally linked to degenerative aortic stenosis. New therapies with ASO (antisense oligonucleotides) and siRNA (small interfering RNA) are currently being tested. Olpasiran and pelacarsen reduce circulating Lp(a) levels by 85-90%. Phase 3 studies are underway to evaluate the effect of these drugs on cardiovascular events (cardiovascular death, non-fatal myocardial injury, and non-fatal stroke) in patients with elevated Lp(a) and CVD (cardiovascular diseases). For instance, if a reduction in Lp(a) levels is associated with aortic stenosis prevention or progression, further prospective clinical trials are warranted to confirm this observation in this high-risk population.

Is Lipoprotein(a) Clinically Actionable with Today's Evidence? The Answer is Yes

PURPOSE OF REVIEW

Lipoprotein(a) is an independent risk factor for cardiovascular disease. We review the ongoing shifts in consensus guidelines for the testing and management of Lp(a) and provide insight into whether current evidence suggests that awareness and testing of Lp(a) is clinically actionable.

RECENT FINDINGS

GWAS and Mendelian randomization studies have established causal links between elevated Lp(a) and forms of CVD, including CAD and calcific aortic valve disease. Testing of Lp(a) identifies patients with similar risk to that of heterozygous FH, enhances risk stratification in patients with borderline/intermediate risk as determined through traditional factors, and facilitates the assessment of inherited CVD risk through cascade screening in patients with known family history of elevated Lp(a). Reductions in Lp(a) through non-targeted therapies including PCSK9 inhibition and lipoprotein apheresis have demonstrated reductions in ASCVD risk that are likely attributable to lowering Lp(a). Targeted therapies to potently lower Lp(a) are in clinical development. Lp(a) is actionable, and can be used to identify high risk patients for primary prevention and their family members through cascade screening, and to guide intensification of therapy in primary and secondary prevention of ASCVD.

Consensus document on Lipoprotein(a) from the Italian Society for the Study of Atherosclerosis (SISA)

AIMS

In view of the consolidating evidence on the causal role of Lp(a) in cardiovascular disease, the Italian Society for the Study of Atherosclerosis (SISA) has assembled a consensus on Lp(a) genetics and epidemiology, together with recommendations for its measurement and current and emerging therapeutic approaches to reduce its plasma levels. Data on the Italian population are also provided.

DATA SYNTHESIS

Lp(a) is constituted by one apo(a) molecule and a lipoprotein closely resembling to a low-density lipoprotein (LDL). Its similarity with an LDL, together with its ability to carry oxidized phospholipids are considered the two main features making Lp(a) harmful for cardiovascular health. Plasma Lp(a) concentrations vary over about 1000 folds in humans and are genetically determined, thus they are quite stable in any individual. Mendelian Randomization studies have suggested a causal role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis and observational studies indicate a linear direct correlation between cardiovascular disease and Lp(a) plasma levels. Lp(a) measurement is strongly recommended once in a patient's lifetime, particularly in FH subjects, but also as part of the initial lipid screening to assess cardiovascular risk. The apo(a) size polymorphism represents a challenge for Lp(a) measurement in plasma, but new strategies are overcoming these difficulties. A reduction of Lp(a) levels can be currently attained only by plasma apheresis and, moderately, with PCSK9 inhibitor treatment.

CONCLUSIONS

Awaiting the approval of selective Lp(a)-lowering drugs, an intensive management of the other risk factors for individuals with elevated Lp(a) levels is strongly recommended.

Lipoprotein(a) as a Risk Factor for Cardiovascular Diseases: Pathophysiology and Treatment Perspectives

Cardiovascular disease (CVD) is still a leading cause of morbidity and mortality, despite all the progress achieved as regards to both prevention and treatment. Having high levels of lipoprotein(a) [Lp(a)] is a risk factor for cardiovascular disease that operates independently. It can increase the risk of developing cardiovascular disease even when LDL cholesterol (LDL-C) levels are within the recommended range, which is referred to as residual cardiovascular risk. Lp(a) is an LDL-like particle present in human plasma, in which a large plasminogen-like glycoprotein, apolipoprotein(a) [Apo(a)], is covalently bound to Apo B100 via one disulfide bridge. Apo(a) contains one plasminogen-like kringle V structure, a variable number of plasminogen-like kringle IV structures (types 1-10), and one inactive protease region. There is a large inter-individual variation of plasma concentrations of Lp(a), mainly ascribable to genetic variants in the Lp(a) gene: in the general po-pulation, Lp(a) levels can range from <1 mg/dL to >1000 mg/dL. Concentrations also vary between different ethnicities. Lp(a) has been established as one of the risk factors that play an important role in the development of atherosclerotic plaque. Indeed, high concentrations of Lp(a) have been related to a greater risk of ischemic CVD, aortic valve stenosis, and heart failure. The threshold value has been set at 50 mg/dL, but the risk may increase already at levels above 30 mg/dL. Although there is a well-established and strong link between high Lp(a) levels and coronary as well as cerebrovascular disease, the evidence regarding incident peripheral arterial disease and carotid atherosclerosis is not as conclusive. Because lifestyle changes and standard lipid-lowering treatments, such as statins, niacin, and cholesteryl ester transfer protein inhibitors, are not highly effective in reducing Lp(a) levels, there is increased interest in developing new drugs that can address this issue. PCSK9 inhibitors seem to be capable of reducing Lp(a) levels by 25-30%. Mipomersen decreases Lp(a) levels by 25-40%, but its use is burdened with important side effects. At the current time, the most effective and tolerated treatment for patients with a high Lp(a) plasma level is apheresis, while antisense oligonucleotides, small interfering RNAs, and microRNAs, which reduce Lp(a) levels by targeting RNA molecules and regulating gene expression as well as protein production levels, are the most widely explored and promising perspectives. The aim of this review is to provide an update on the current state of the art with regard to Lp(a) pathophysiological mechanisms, focusing on the most effective strategies for lowering Lp(a), including new emerging alternative therapies. The purpose of this manuscript is to improve the management of hyperlipoproteinemia(a) in order to achieve better control of the residual cardiovascular risk, which remains unacceptably high.

Considerations for routinely testing for high lipoprotein(a)

PURPOSE OF REVIEW

Lipoprotein (a) [Lp(a)] is a likely causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and aortic valve disease, confirmed by Mendelian randomization. With reliable assays, it has been established that Lp(a) is linearly associated with ASCVD. Current low-density lipoprotein cholesterol (LDL-C) lowering therapies do not or minimally lower Lp(a). This review focuses on the clinical importance and therapeutic consequences of Lp(a) measurement.

RECENT FINDINGS

Development of RNA-based Lp(a) lowering therapeutics has positioned Lp(a) as one of the principal residual risk factors to target in the battle against lipid-driven ASCVD risk. Pelacarsen, which is a liver-specific antisense oligonucleotide, has shown Lp(a) reductions up to 90% and its phase 3 trial is currently underway. Olpasiran is a small interfering RNA targeting LPA messenger RNA, which is being investigated in phase 2 and has already shown dose-dependent Lp(a) reductions up to 90%.

SUMMARY

Lp(a) should be measured in every patient at least once to identify patients with very high Lp(a) levels. These patients could benefit from Lp(a) lowering therapies when approved. In the meantime, therapy in high Lp(a) patients should focus on further reducing LDL-C and other ASCVD risk factors.

Lipoprotein(a) and calcific aortic valve disease initiation and progression: a systematic review and meta-analysis

Although evidence indicates the association of lipoprotein(a) [Lp(a)] with atherosclerosis, the link with calcific aortic valve disease (CAVD) is unclear. This systematic review and meta-analysis explores the connection between Lp(a) and aortic valve calcification and stenosis (AVS). We included all relevant studies, indexed in eight databases, up to February 2023. A total of 44 studies (163 139 subjects) were included, with 16 of them being further meta-analysed. Despite considerable heterogeneity, most studies support the relationship between Lp(a) and CAVD, especially in younger populations, with evidence of early aortic valve micro-calcification in elevated-Lp(a) populations. The quantitative synthesis showed higher Lp(a) levels, by 22.63 nmol/L (95% CI: 9.98-35.27), for patients with AVS, while meta-regressing the data revealed smaller Lp(a) differences for older populations with a higher proportion of females. The meta-analysis of eight studies providing genetic data, revealed that the minor alleles of both rs10455872 and rs3798220 LPA gene loci were associated with higher risk for AVS (pooled odds ratio 1.42; 95% CI: 1.34-1.50 and 1.27; 95% CI: 1.09-1.48, respectively). Importantly, high-Lp(a) individuals displayed not only faster AVS progression, by a mean difference of 0.09 m/s/year (95% CI: 0.09-0.09), but also a higher risk of serious adverse outcomes, including death (pooled hazard ratio 1.39; 95% CI: 1.01-1.90). These summary findings highlight the effect of Lp(a) on CAVD initiation, progression and outcomes, and support the early onset of Lp(a)-related subclinical lesions before clinical evidence.

Lipoprotein(a) in clinical practice: A guide for the clinician

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Serum lipoprotein(a) (Lp(a)) has been shown to be an independent and causative risk factor for atherosclerotic CVD and calcific aortic valvular disease. Lp(a) continues to be studied, with emerging insights into the epidemiology of CVD with respect to Lp(a), pathogenic mechanisms of Lp(a) and strategies to mitigate disease. There have been novel insights into genetic polymorphisms of the LPA gene, interactions between concomitant risk factors and Lp(a) based on real-world data, and metabolic pathway targets for Lp(a) reduction. This review highlights these recent advances in our understanding of Lp(a) and discusses management strategies as recommended by cardiovascular professional societies, emerging therapies for lowering Lp(a), and future directions in targeting Lp(a) to reduce CVD.

Lipoprotein(a) As a Potential Predictive Factor for Earlier Aortic Valve Replacement in Patients with Bicuspid Aortic Valve

Bicuspid aortic valve (BAV) affects 0.5-2% of the general population and constitutes the major cause of severe aortic valve stenosis (AVS) in individuals ≤70 years. The aim of the present study was to evaluate the parameters that may provide information about the risk of AVS developing in BAV patients, with particular emphasis on lipoprotein(a) (Lp(a)), which is a well-recognized risk factor for stenosis in the general population. We also analyzed the impact of autotaxin (ATX) and interleukin-6 (IL-6) as parameters potentially related to the pathomechanism of Lp(a) action. We found that high Lp(a) levels (>50 mg/dL) occurred significantly more frequently in patients with AVS than in patients without AVS, both in the group below and above 45 years of age (p = 0.036 and p = 0.033, respectively). Elevated Lp(a) levels were also strictly associated with the need for aortic valve replacement (AVR) at a younger age (p = 0.016). However, the Lp(a) concentration did not differ significantly between patients with and without AVS. Similarly, we observed no differences in ATX between the analyzed patient groups, and both ATX activity and concentration correlated significantly with Lp(a) level (R = 0.465, p < 0.001 and R = 0.599, p < 0.001, respectively). We revealed a significantly higher concentration of IL-6 in young patients with AVS. However, this observation was not confirmed in the group of patients over 45 years of age. We also did not observe a significant correlation between IL-6 and Lp(a) or between CRP and Lp(a) in any of the analyzed groups of BAV patients. Our results demonstrate that a high level of Lp(a), greater than 50 mg/dL, may be a significant predictive factor for earlier AVR. Lp(a)-related parameters, such as ATX and IL-6, may be valuable in providing information about the additional cardiovascular risks associated with developing AVS.

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.

Serum lipoprotein(a) and bioprosthetic aortic valve degeneration

AIMS

Bioprosthetic aortic valve degeneration demonstrates pathological similarities to aortic stenosis. Lipoprotein(a) [Lp(a)] is a well-recognized risk factor for incident aortic stenosis and disease progression. The aim of this study is to investigate whether serum Lp(a) concentrations are associated with bioprosthetic aortic valve degeneration.

METHODS AND RESULTS

In a post hoc analysis of a prospective multimodality imaging study (NCT02304276), serum Lp(a) concentrations, echocardiography, contrast-enhanced computed tomography (CT) angiography, and 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) were assessed in patients with bioprosthetic aortic valves. Patients were also followed up for 2 years with serial echocardiography. Serum Lp(a) concentrations [median 19.9 (8.4-76.4) mg/dL] were available in 97 participants (mean age 75 ± 7 years, 54% men). There were no baseline differences across the tertiles of serum Lp(a) concentrations for disease severity assessed by echocardiography [median peak aortic valve velocity: highest tertile 2.5 (2.3-2.9) m/s vs. lower tertiles 2.7 (2.4-3.0) m/s, P = 0.204], or valve degeneration on CT angiography (highest tertile n = 8 vs. lower tertiles n = 12, P = 0.552) and 18F-NaF PET (median tissue-to-background ratio: highest tertile 1.13 (1.05-1.41) vs. lower tertiles 1.17 (1.06-1.53), P = 0.889]. After 2 years of follow-up, there were no differences in annualized change in bioprosthetic hemodynamic progression [change in peak aortic valve velocity: highest tertile [0.0 (-0.1-0.2) m/s/year vs. lower tertiles 0.1 (0.0-0.2) m/s/year, P = 0.528] or the development of structural valve degeneration.

CONCLUSION

Serum lipoprotein(a) concentrations do not appear to be a major determinant or mediator of bioprosthetic aortic valve degeneration.

Atherosclerosis Calcification: Focus on Lipoproteins

Atherosclerosis is a chronic inflammatory disease characterized by the accumulation of lipids in the vessel wall, leading to the formation of an atheroma and eventually to the development of vascular calcification (VC). Lipoproteins play a central role in the development of atherosclerosis and VC. Both low- and very low-density lipoproteins (LDL and VLDL) and lipoprotein (a) (Lp(a)) stimulate, while high-density lipoproteins (HDL) reduce VC. Apolipoproteins, the protein component of lipoproteins, influence the development of VC in multiple ways. Apolipoprotein AI (apoAI), the main protein component of HDL, has anti-calcific properties, while apoB and apoCIII, the main protein components of LDL and VLDL, respectively, promote VC. The role of lipoproteins in VC is also related to their metabolism and modifications. Oxidized LDL (OxLDL) are more pro-calcific than native LDL. Oxidation also converts HDL from anti- to pro-calcific. Additionally, enzymes such as autotaxin (ATX) and proprotein convertase subtilisin/kexin type 9 (PCSK9), involved in lipoprotein metabolism, have a stimulatory role in VC. In summary, a better understanding of the mechanisms by which lipoproteins and apolipoproteins contribute to VC will be crucial in the development of effective preventive and therapeutic strategies for VC and its associated cardiovascular disease.

Lipoprotein(a) and Its Autoantibodies in Association with Calcific Aortic Valve Stenosis

Aortic valve stenosis is the most common valvular heart disease in the Western world. Lipoprotein(a) (Lp(a)) is an independent risk factor of coronary heart disease (CHD) and calcific aortic valve stenosis (CAVS). The aim of this study was to assess the role of Lp(a) and its autoantibodies [autoAbs] in CAVS in patients with and without CHD. We included 250 patients (mean age 69 ± 3 years, males 42%) and divided them into three groups. There were two groups of patients with CAVS depending on the presence (group 1) or absence of CHD (group 2). The control group included the patients without CHD or CAVS. According to logistic regression analysis, levels of Lp(a), IgM autoAbs to oxidized Lp(a) (oxLp(a)), and age were independent predictors of CAVS. A concomitant increase in Lp(a) level (≥30 mg/dL) and a decrease in IgM autoAbs concentration (<9.9 lab. Units) are associated with CAVS with an odds ratio (OR) of 6.4, p < 0.01, and with CAVS and CHD with an OR of 17.3, p < 0.001. IgM autoantibodies to oxLp(a) are associated with calcific aortic valve stenosis regardless of Lp(a) concentration and other risk factors. Higher Lp(a) and lower IgM autoantibodies to oxLp(a) levels are associated with a much higher risk of calcific aortic valve stenosis.

Impact of C-reactive protein levels on lipoprotein(a)-associated aortic stenosis incidence and progression

Aims

Elevated lipoprotein(a) [Lp(a)] levels are associated with the risk of coronary artery disease (CAD) and calcific aortic valve stenosis (CAVS). Observational studies revealed that Lp(a) and C-reactive protein (CRP) levels, a biomarker of systemic inflammation, may jointly predict CAD risk. Whether Lp(a) and CRP levels also jointly predict CAVS incidence and progression is unknown.

Methods and results

We investigated the association of Lp(a) with CAVS according to CRP levels in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study (n = 18 226, 406 incident cases) and the UK Biobank (n = 438 260, 4582 incident cases), as well as in the ASTRONOMER study (n = 220), which assessed the haemodynamic progression rate of pre-existing mild-to-moderate aortic stenosis. In EPIC-Norfolk, in comparison to individuals with low Lp(a) levels (<50 mg/dL) and low CRP levels (<2.0 mg/L), those with elevated Lp(a) (>50 mg/dL) and low CRP levels (<2.0 mg/L) and those with elevated Lp(a) (>50 mg/dL) and elevated CRP levels (>2.0 mg/L) had a higher CAVS risk [hazard ratio (HR) = 1.86 (95% confidence intervals, 1.30-2.67) and 2.08 (1.44-2.99), respectively]. A comparable predictive value of Lp(a) in patients with vs. without elevated CRP levels was also noted in the UK Biobank. In ASTRONOMER, CAVS progression was comparable in patients with elevated Lp(a) levels with or without elevated CRP levels.

Conclusion

Lp(a) predicts the incidence and possibly progression of CAVS regardless of plasma CRP levels. Lowering Lp(a) levels may warrant further investigation in the prevention and treatment of CAVS, regardless of systemic inflammation.

Calcific aortic valve disease: mechanisms, prevention and treatment

Calcific aortic valve disease (CAVD) is the most common disorder affecting heart valves and is characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. Analyses of surgically explanted aortic valve leaflets have shown that dystrophic mineralization and osteogenic transition of valve interstitial cells co-occur with neovascularization, microhaemorrhage and abnormal production of extracellular matrix. Age and congenital bicuspid aortic valve morphology are important and unalterable risk factors for CAVD, whereas additional risk is conferred by elevated blood pressure and plasma lipoprotein(a) levels and the presence of obesity and diabetes mellitus, which are modifiable factors. Genetic and molecular studies have identified that the NOTCH, WNT-β-catenin and myocardin signalling pathways are involved in the control and commitment of valvular cells to a fibrocalcific lineage. Complex interactions between valve endothelial and interstitial cells and immune cells promote the remodelling of aortic valve leaflets and the development of CAVD. Although no medical therapy is effective for reducing or preventing the progression of CAVD, studies have started to identify actionable targets.

Lipoprotein(a): Its Association with Calcific Aortic Valve Stenosis, the Emerging RNA-Related Treatments and the Hope for a New Era in “Treating” Aortic Valve Calcification

The treatment of patients with aortic valve calcification (AVC) and calcific aortic valve stenosis (CAVS) remains challenging as, until today, all non-invasive interventions have proven fruitless in preventing the disease’s onset and progression. Despite the similarities in the pathogenesis of AVC and atherosclerosis, statins failed to show a favorable effect in preventing AVC progression. The recognition of lipoprotein(a) [Lp(a)] as a strong and potentially modifiable risk factor for the development and, perhaps, the progression of AVC and CAVS and the evolution of novel agents leading in a robust Lp(a) reduction, have rekindled hope for a promising future in the treatment of those patients. Lp(a) seems to promote AVC via a ‘three hit’ mechanism including lipid deposition, inflammation and autotaxin transportation. All of these lead to valve interstitial cells transition into osteoblast-like cells and, thus, to parenchymal calcification. Currently available lipid-lowering therapies have shown a neutral or mild effect on Lp(a), which was proven insufficient to contribute to clinical benefits. The short-term safety and the efficacy of the emerging agents in reducing Lp(a) have been proven; nevertheless, their effect on cardiovascular risk is currently under investigation in phase 3 clinical trials. A positive result of these trials will probably be the spark to test the hypothesis of the modification of AVC’s natural history with the novel Lp(a)-lowering agents.

Body Mass Index and Mortality from Nonrheumatic Aortic Valve Disease among Japanese Men and Women

AIM

We aimed to examine the impact of overweight and obesity on mortality from nonrheumatic aortic valve disease.

METHODS

In the Japan Collaborative Cohort Study, we analyzed data of 98,378 participants aged 40-79 years, with no history of coronary heart disease, stroke, or cancer at baseline (1988-1990) and who completed a lifestyle questionnaire including height and body weight; they were followed for mortality until the end of 2009. The Cox proportional hazards model was used to calculate the multivariable hazard ratios (HRs) with 95% confidence intervals (CIs) of nonrheumatic aortic valve disease mortality according to body mass index (BMI) after adjusting for potential confounding factors.

RESULTS

During the median 19.2 years follow-up, 60 deaths from nonrheumatic aortic valve disease were reported. BMI was positively associated with the risk of mortality from nonrheumatic aortic valve disease; the multivariable HRs (95% CIs) were 0.90 (0.40-2.06) for persons with BMI ＜21 kg/m2, 1.71 (0.81-3.58) for BMI 23-24.9 kg/m2, 1.65 (0.69-3.94) for BMI 25-26.9 kg/m2, and 2.83 (1.20-6.65) for BMI ≥ 27 kg/m2 (p for trend=0.006), compared with persons with BMI 21-22.9 kg/m2. Similar associations were observed between men and women (p for interaction=0.56). Excluding those who died during the first ten years of follow-up or a competing risk analysis with other causes of death as competing risk events did not change the association materially.

CONCLUSIONS

Overweight and obesity may be independent risk factors for nonrheumatic aortic valve disease mortality in Asian populations.

Lipoprotein(a): a risk factor for atherosclerosis and an emerging therapeutic target

Lipoprotein(a) (Lp(a)) is a complex circulating lipoprotein, and increasing evidence has demonstrated its role as a risk factor for atherosclerotic cardiovascular disease (ASCVD) and as a possible therapeutic target. Lp(a) atherogenic effects are attributed to several potential mechanisms in addition to cholesterol accumulation in the arterial wall, including proinflammatory effects mainly mediated by oxidised phospholipids. Several studies have found a causal and independent relationship between Lp(a) levels and cardiovascular risk. Furthermore, several studies also suggest a causal association between Lp(a) levels and calcific aortic valve stenosis. Available lipid-lowering agents have at best moderate impact on Lp(a) levels. Among available therapies, antibody proprotein convertase subtilisin/kexin type 9 inhibitors are the most effective in reducing Lp(a). Potent Lp(a)-lowering treatments that target LPA expression are under development. Lp(a) level measurement poses some challenges due to the absence of a definitive reference method and the reporting of Lp(a) values as molar (nanomoles per litre (nmol/L)) or mass concentrations (milligrams per decilitre (mg/dL)) by different assays. Currently, Lp(a) measurement is recommended to refine cardiovascular risk in specific clinical settings, that is, in individuals with a family history of premature ASCVD, in patients with ASCVD not explained by standard risk factors or in those with recurrent events despite optimal management of traditional risk factors. Patients with high Lp(a) levels should be managed with more intensive approaches to treat other modifiable cardiovascular risk factors. Overall, this review focuses on Lp(a) as an ASCVD risk factor and therapeutic target. Furthermore, it reports practical recommendations for Lp(a) measurement and interpretation and updated evidence on Lp(a)-lowering approaches.

Lipoprotein (a) Levels and Abdominal Aortic Aneurysm. A Systematic Review and Meta-analysis

BACKGROUND

Several studies have linked high Lipoprotein (a) (Lp(a)) concentrations to cardiovascular events, including the formation of Abdominal Aortic Aneurysms (AAA). We review and meta-analyze existing evidence on the association of Lp(a) levels with AAA.

METHODS

Studies evaluating the link of Lp(a) with AAA, up to December 27th 2021, were identified by a systematic search of PubMed, SCOPUS, and Web of Science databases. The results were qualitatively and quantitatively synthesized according to PRISMA guidelines. Results are presented as standardized mean differences (SMD) with 95% confidence intervals (CI).

RESULTS

A total of 5,078 subjects (1,637 patients with AAA vs. 3,441 controls) from 11 studies were included in the meta-analysis, with a mean age of 69.9 years and a male sex prevalence of 85.8%. Based on the qualitative synthesis, high Lp(a) concentrations are linked to abdominal aortic wall degradation and extracellular matrix disarrangement. Moreover, despite the considerable variability among races, high Lp(a) levels are related to increased AAA risk, independently of race differences. Accordingly, patients with AAA displayed significantly higher Lp(a) levels compared to controls (SMD: 0.86, 95% CI: 0.55-1.17, p < 0.001). The outcome was not affected in a sensitivity analysis excluding three outlying studies (SMD: 0.40, 95% CI: 0.22-0.58, p < 0.001).

CONCLUSION

This meta-analysis indicates the association between high Lp(a) levels and the presence of AAA, although existing literature presents high heterogeneity. Further studies are needed to standardize Lp(a) measurements and to conclude whether Lp(a) can be used as a sensitive biomarker of early presymptomatic AAA diagnosis.

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.

IL6 gene polymorphism association with calcific aortic valve stenosis and influence on serum levels of interleukin-6

Aortic valve stenosis is the most frequent valve disease in developed countries and its prevalence will increase with population aging. There is still no pharmaceutical treatment nor biomarker to determine the susceptibility to develop aortic stenosis. Therefore, we analyzed the association of polymorphisms in risk loci with calcific aortic stenosis. Patients with aortic valve disease were genotyped for PALMD rs6702619, LPA rs10455872, and IL6 rs1800795 polymorphisms and circulating levels of interleukin-6 (IL-6) were measured. Calcium content of leaflets obtained in valve replacement surgeries was determined by micro-computed tomography. In the genotyping of 578 individuals, we found significant association between PALMD and IL6 polymorphisms and aortic stenosis in patients with tricuspid aortic valve, independently of other potentially confounding variables such as age and dyslipidemia. There was no association of these polymorphisms with valve calcium content, but this value correlated with the mean aortic pressure gradient (r = 0.44; P < 0.001). The CC genotype of IL6 polymorphism was associated with higher levels of serum IL-6 compared to other genotypes (23.5 vs. 10.5 pg/ml, respectively; P = 0.029). Therefore, patients carrying the CC genotype of IL6 rs1800795 polymorphism present higher levels of circulating IL-6 and this could contribute to the severity of the aortic valve stenosis. Our results agree with the identification of IL6 as a locus risk for stenosis and also with the intervention of this cytokine in aortic valve calcification. A more exhaustive follow-up of those patients carrying risk genotypes is therefore recommended.

Lipoprotein(a): Evidence for Role as a Causal Risk Factor in Cardiovascular Disease and Emerging Therapies

Lipoprotein(a) (Lp(a)) is an established risk factor for multiple cardiovascular diseases. Several lines of evidence including mechanistic, epidemiologic, and genetic studies support the role of Lp(a) as a causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and aortic stenosis/calcific aortic valve disease (AS/CAVD). Limited therapies currently exist for the management of risk associated with elevated Lp(a), but several targeted therapies are currently in various stages of clinical development. In this review, we detail evidence supporting Lp(a) as a causal risk factor for ASCVD and AS/CAVD, and discuss approaches to managing Lp(a)-associated risk.

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.

Use of Lipoprotein(a) in clinical practice: A biomarker whose time has come. A scientific statement from the National Lipid Association

Lipoprotein(a) [Lp(a)] is a well-recognized, independent risk factor for atherosclerotic cardiovascular disease, with elevated levels estimated to be prevalent in 20% of the population. Observational and genetic evidence strongly support a causal relationship between high plasma concentrations of Lp(a) and increased risk of atherosclerotic cardiovascular disease-related events, such as myocardial infarction and stroke, and valvular aortic stenosis. In this scientific statement, we review an array of evidence-based considerations for testing of Lp(a) in clinical practice and the utilization of Lp(a) levels to inform treatment strategies in primary and secondary prevention.

Lipoprotein(a) is associated with the onset but not the progression of aortic valve calcification

AIM

Lipoprotein(a) [Lp(a)] is a potential causal factor in the pathogenesis of aortic valve disease. However, the relationship of Lp(a) with new onset and progression of aortic valve calcium (AVC) has not been studied. The purpose of the study was to assess whether high serum levels of Lp(a) are associated with AVC incidence and progression.

METHODS AND RESULTS

A total of 922 individuals from the population-based Rotterdam Study (mean age 66.0±4.2 years, 47.7% men), whose Lp(a) measurements were available, underwent non-enhanced cardiac computed tomography imaging at baseline and after a median follow-up of 14.0 [interquartile range (IQR) 13.9-14.2] years. New-onset AVC was defined as an AVC score >0 on the follow-up scan in the absence of AVC on the first scan. Progression was defined as the absolute difference in AVC score between the baseline and follow-up scan. Logistic and linear regression analyses were performed to evaluate the relationship of Lp(a) with baseline, new onset, and progression of AVC. All analyses were corrected for age, sex, body mass index, smoking, hypertension, dyslipidaemia, and creatinine. AVC progression was analysed conditional on baseline AVC score expressed as restricted cubic splines. Of the 702 individuals without AVC at baseline, 415 (59.1%) developed new-onset AVC on the follow-up scan. In those with baseline AVC, median annual progression was 13.5 (IQR = 5.2-37.8) Agatston units (AU). Lipoprotein(a) concentration was independently associated with baseline AVC [odds ratio (OR) 1.43 for each 50 mg/dL higher Lp(a); 95% confidence interval (CI) 1.15-1.79] and new-onset AVC (OR 1.30 for each 50 mg/dL higher Lp(a); 95% CI 1.02-1.65), but not with AVC progression (β: -71 AU for each 50 mg/dL higher Lp(a); 95% CI -117; 35). Only baseline AVC score was significantly associated with AVC progression (P < 0.001).

CONCLUSION

In the population-based Rotterdam Study, Lp(a) is robustly associated with baseline and new-onset AVC but not with AVC progression, suggesting that Lp(a)-lowering interventions may be most effective in pre-calcific stages of aortic valve disease.

The mechanistic pathways of oxidative stress in aortic stenosis and clinical implications

Despite the elucidation of the pathways behind the development of aortic stenosis (AS), there remains no effective medical treatment to slow or reverse its progress. Instead, the gold standard of care in severe or symptomatic AS is replacement of the aortic valve. Oxidative stress is implicated, both directly as well as indirectly, in lipid infiltration, inflammation and fibro-calcification, all of which are key processes underlying the pathophysiology of degenerative AS. This culminates in the breakdown of the extracellular matrix, differentiation of the valvular interstitial cells into an osteogenic phenotype, and finally, calcium deposition as well as thickening of the aortic valve. Oxidative stress is thus a promising and potential therapeutic target for the treatment of AS. Several studies focusing on the mitigation of oxidative stress in the context of AS have shown some success in animal and in vitro models, however similar benefits have yet to be seen in clinical trials. Statin therapy, once thought to be the key to the treatment of AS, has yielded disappointing results, however newer lipid lowering therapies may hold some promise. Other potential therapies, such as manipulation of microRNAs, blockade of the renin-angiotensin-aldosterone system and the use of dipeptidylpeptidase-4 inhibitors will also be reviewed.

Implication of Lipids in Calcified Aortic Valve Pathogenesis: Why Did Statins Fail?

Calcific Aortic Valve Disease (CAVD) is a fibrocalcific disease. Lipoproteins and oxidized phospholipids play a substantial role in CAVD; the level of Lp(a) has been shown to accelerate the progression of valve calcification. Indeed, oxidized phospholipids carried by Lp(a) into the aortic valve stimulate endothelial dysfunction and promote inflammation. Inflammation and growth factors actively promote the synthesis of the extracellular matrix (ECM) and trigger an osteogenic program. The accumulation of ECM proteins promotes lipid adhesion to valve tissue, which could initiate the osteogenic program in interstitial valve cells. Statin treatment has been shown to have the ability to diminish the death rate in subjects with atherosclerotic impediments by decreasing the serum LDL cholesterol levels. However, the use of HMG-CoA inhibitors (statins) as cholesterol-lowering therapy did not significantly reduce the progression or the severity of aortic valve calcification. However, new clinical trials targeting Lp(a) or PCSK9 are showing promising results in reducing the severity of aortic stenosis. In this review, we discuss the implication of lipids in aortic valve calcification and the current findings on the effect of lipid-lowering therapy in aortic stenosis.

Considerations for routinely testing for high Lp(a)

PURPOSE OF REVIEW

Lipoprotein(a) (Lp[a]) is a likely causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and aortic valve disease, confirmed by Mendelian randomization. With reliable assays, it has been established that Lp(a) is linearly associated with ASCVD. Current low-density lipoprotein cholesterol (LDL-C) lowering therapies do not or minimally lower Lp(a). This review focuses on the clinical importance and therapeutic consequences of Lp(a) measurement.

RECENT FINDINGS

Development of RNA-based Lp(a) lowering therapeutics has positioned Lp(a) as one of the principal residual risk factors to target in the battle against lipid-driven ASCVD risk. Pelacarsen, which is a liver-specific antisense oligonucleotide, has shown Lp(a) reductions up to 90% and its phase 3 trial is currently underway. Olpasiran is a small interfering RNA targeting LPA messenger RNA which is being investigated in phase 2 and has already shown dose-dependent Lp(a) reductions up to 90%.

SUMMARY

Lp(a) should be measured in every patient at least once to identify patients with very high Lp(a) levels. These patients could benefit from Lp(a) lowering therapies when approved. In the meantime, therapy in high Lp(a) patients should focus on further reducing LDL-C and other ASCVD risk factors.

Lipoprotein(a) and cardiovascular and valvular diseases: A genetic epidemiological perspective

Rates of atherosclerotic cardiovascular diseases (CVD) in the Western world have spectacularly decreased over the past 50 years. However, a substantial proportion of high-risk patients still develop heart attacks, strokes and valvular heart diseases despite benefiting from state-of-the-art treatments including lipid-lowering therapies. Over the past 10-15 years, it has become increasingly clear that Lipoprotein(a) (Lp[a]) is a critical component of this so-called residual risk. Genetic association studies revealed that Lp(a) is robustly, independently and causally associated with a broad range of cardiovascular and valvular heart diseases. Up to 1 billion people around the globe may have an Lp(a) level that places them in a high-risk category. Lp(a) is strongly associated with calcific aortic valve stenosis (CAVS), coronary artery disease (CAD), peripheral arterial disease (PAD) and to a lesser extent with ischemic stroke (IS) and heart failure (HF). Because of this strong association with cardiovascular and valvular heart diseases, Lp(a) even emerged as one of the most important genetic determinants of human lifespan and healthspan. Here, we review the evidence from the largest and most informative genetic association studies and prospective studies that have investigated the association between Lp(a) and human lifespan, healthspan, CVD, CAVS and non-cardiovascular diseases. We present Lp(a) threshold values that may be clinically relevant and identify other cardiovascular risk factors that may modulate the absolute risk of CVD in individuals with high Lp(a) levels. Finally, we identify key clinical and research questions that require further investigation to eventually and optimally reduce CVD risk in patients with high Lp(a) levels.

Lipoprotein(a) and its Significance in Cardiovascular Disease: A Review

Importance

Lipoprotein(a) (Lp[a]) is a low-density lipoprotein (LDL) cholesterol-like particle bound to apolipoprotein(a). This novel marker of cardiovascular disease acts through induction of vascular inflammation, atherogenesis, calcification, and thrombosis. While an absolute risk threshold remains to be universally accepted, an estimated 20% to 25% of the global population have Lp(a) levels of 50 mg/dL or higher, a level noted by the European Atherosclerosis Society to confer increased cardiovascular risk.

Observations

Compelling evidence from pathophysiological, observational, and genetic studies suggest a potentially causal association between high Lp(a) levels, atherosclerotic cardiovascular disease, and calcific aortic valve stenosis. Additional evidence has demonstrated that elevated Lp(a) levels are associated with a residual cardiovascular risk despite traditional risk factor optimization, including LDL cholesterol reduction. These findings have led to the formulation of the Lp(a) hypothesis, namely that Lp(a) lowering leads to cardiovascular risk reduction, intensifying the search for Lp(a)-reducing therapies. The ineffectiveness of lifestyle modification, statins, and ezetimibe to lower Lp(a); the modest Lp(a) reduction with proprotein convertase subtilisin/kexin type 9 inhibitors; the adverse effect profile and unclear cardiovascular benefit of pharmacotherapies such as niacin and mipomersen; and the impracticality of regular lipoprotein apheresis represent major challenges to currently available therapies. Nevertheless, emerging nucleic acid-based therapies, such as the antisense oligonucleotide pelacarsen and the small interfering RNA olpasiran, are generating interest because of their potent Lp(a)-lowering effects. Assessment of new-onset diabetes in patients achieving very low Lp(a) levels will be important in future trials.

Conclusions and Relevance

Epidemiologic and genetic studies suggest a potentially causal association between elevated Lp(a) levels, atherosclerotic cardiovascular disease, and aortic valve stenosis. Emerging nucleic acid-based therapies have potent Lp(a)-lowering effects and appear safe; phase 3 trials will establish whether they improve cardiovascular outcomes.