Lipoprotein (a): When to Measure and How to Treat?

Independent Relationship of Lipoprotein(a) and Carotid Atherosclerosis With Long-Term Risk of Cardiovascular Disease

BACKGROUND

Lipoprotein(a) (Lp(a)) is considered to be a causal risk factor of atherosclerotic cardiovascular disease (ASCVD), but whether there is an independent or joint association of Lp(a) and atherosclerotic plaque with ASCVD risk remains uncertain. This study aims to assess ASCVD risk independently or jointly conferred by Lp(a) and carotid atherosclerotic plaque.

METHODS AND RESULTS

A total of 5471 participants with no history of cardiovascular disease at baseline were recruited and followed up for ASCVD events (all fatal and nonfatal acute coronary and ischemic stroke events) over a median of 11.5 years. Independent association of Lp(a), or the joint association of Lp(a) and carotid plaque with ASCVD risk, was explored using Cox proportional hazards models. Overall, 7.6% of the participants (60.0±7.9 years of age; 2649 [48.4%] men) had Lp(a) ≥50 mg/dL, and 539 (8.4/1000 person-years) incident ASCVD events occurred. Lp(a) concentrations were independently associated with long-term risk of total ASCVD events, as well as coronary events and ischemic stroke events. Participants with Lp(a) ≥50 mg/dL had a 62% higher risk of ASCVD incidence (95% CI, 1.19-2.21) than those with Lp(a) <10 mg/dL, and they exhibited a 10-year ASCVD incidence of 11.7%. This association exists even after adjusting for prevalent plaque. Moreover, participants with Lp(a) ≥30 mg/dL and prevalent plaque had a significant 4.18 times higher ASCVD risk than those with Lp(a) <30 mg/dL and no plaque.

CONCLUSIONS

Higher Lp(a) concentrations are independently associated with long-term ASCVD risk and may exaggerate cardiovascular risk when concomitant with atherosclerotic plaque.

Lipoprotein(a): An important piece of the ASCVD risk factor puzzle across diverse populations

Elevated lipoprotein(a) (Lp[a]) is an independent, genetic risk factor for atherosclerotic cardiovascular disease (ASCVD) that impacts ~1.4 billion people globally. Generally, Lp(a) levels remain stable over time; thus, most individuals need only undergo Lp(a) testing through a non-fasting blood draw once in their lifetime, unless elevated Lp(a) is identified. Despite the convenience of the test for clinicians and patients, routine Lp(a) testing has not been widely adopted. This review provides a guide to the benefits of Lp(a) testing and solutions for overcoming common barriers in practice, including access to testing and lack of awareness. Lp(a) testing provides the opportunity to reclassify ASCVD risk and drive intensive cardiovascular risk factor management in individuals with elevated Lp(a), and to identify patients potentially less likely to respond to statins. Moreover, cascade screening can help to identify elevated Lp(a) in relatives of individuals with a personal or family history of premature ASCVD. Overall, given the profound impact of elevated Lp(a) on cardiovascular risk, Lp(a) testing should be an essential component of risk assessment by primary and specialty care providers.

Relationship Between Lipoprotein(a), Renal Function Indicators, and Chronic Kidney Disease: Evidence From a Large Prospective Cohort Study

BACKGROUND

Chronic kidney disease (CKD) poses a significant global public health challenge. While lipoprotein(a) (Lp[a]) has been established as a significant factor in cardiovascular disease, its connection to CKD risk remains a topic of debate. Existing evidence indicates diverse risks of kidney disease among individuals with various renal function indicators, even when within the normal range.

OBJECTIVE

This study aims to investigate the joint associations between different renal function indicators and Lp(a) regarding the risks of incident CKD in the general population.

METHODS

The analysis involved a cohort of 329,415 participants without prior CKD who were enrolled in the UK Biobank between 2006 and 2010. The participants, with an average age of 56 (SD 8.1) years, included 154,298/329,415 (46.84%) males. At baseline, Lp(a) levels were measured using an immunoturbidimetric assay and classified into 2 groups: low (<75 nmol/L) and high (≥75 nmol/L). To assess participants' baseline renal function, we used the baseline urine albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR). The relationship between Lp(a), renal function indicators, and the risk of CKD was evaluated using multivariable Cox regression models. These models were adjusted for various factors, including sociodemographic variables, lifestyle factors, comorbidities, and laboratory measures.

RESULTS

A total of 6003 incident CKD events were documented over a median follow-up period of 12.5 years. The association between elevated Lp(a) levels and CKD risk did not achieve statistical significance among all participants, with a hazard ratio (HR) of 1.05 and a 95% CI ranging from 0.98 to 1.13 (P=.16). However, a notable interaction was identified between Lp(a) and UACR in relation to CKD risk (P for interaction=.04), whereas no significant interaction was observed between Lp(a) and eGFR (P for interaction=.96). When compared with the reference group with low Lp(a) and low-normal UACR (<10 mg/g), the group with high Lp(a) and low-normal UACR exhibited a nonsignificant association with CKD risk (HR 0.98, 95% CI 0.90-1.08; P=.74). By contrast, both the low Lp(a) and high-normal UACR (≥10 mg/g) group (HR 1.16, 95% CI 1.08-1.24; P<.001) and the high Lp(a) and high-normal UACR group (HR 1.32, 95% CI 1.19-1.46; P<.001) demonstrated significant associations with increased CKD risks. In individuals with high-normal UACR, elevated Lp(a) was linked to a significant increase in CKD risk, with an HR of 1.14 and a 95% CI ranging from 1.03 to 1.26 (P=.01). Subgroup analyses and sensitivity analyses consistently produced results that were largely in line with the main findings.

CONCLUSIONS

The analysis revealed a significant interaction between Lp(a) and UACR in relation to CKD risk. This implies that Lp(a) may act as a risk factor for CKD even when considering UACR. Our findings have the potential to provide valuable insights into the assessment and prevention of CKD, emphasizing the combined impact of Lp(a) and UACR from a public health perspective within the general population. This could contribute to enhancing public awareness regarding the management of Lp(a) for the prevention of CKD.

Clinical characteristics associated with elevated levels of lipoprotein(a) in patients with vascular risk

Objectives

Lipoprotein(a) (Lp(a)) is increasingly used in the evaluation of patients with vascular risk due to its association with cardiovascular events. The purpose of this study was to identify the clinical characteristics of patients with elevated levels of Lp(a) attended in an outpatient vascular risk unit.

Methods

An observational, retrospective study was conducted to assess the clinical characteristics of patients with elevated levels of Lp(a) (≥50 mg/dL), as compared to patients with normal values (<50 mg/dL). The sample was composed of 878 patients identified as having a high vascular risk due to a diagnosis of vascular disease, attended in a vascular risk unit between 2021 and 2022.

Results

The highest levels of Lp(a) were independently associated with a higher probability of having a history of peripheral arterial disease (p=0.024), polygenic familial hypercholesterolemia (PH, p=0.030) and combined familial hypercholesterolemia (CFH, p=0.015); and using PCSK9 inhibitor treatment (p=0.029) and combination therapy with statins and ezetimibe (p=0.018). In contrast, there were no significant differences in relation to familial history of early cardiovascular disease (p=0.143) or personal history of cardiovascular disease (p=0.063), which contrasts with other series.

Conclusions

Elevated levels of Lp(a) were associated with a history of peripheral arterial disease, diagnosis of FHP and CFH, and need for more intense lipid-lowering treatments.

Residual risks and evolving atherosclerotic plaques

Atherosclerotic disease of the coronary and carotid arteries is the primary global cause of significant mortality and morbidity. The chronic occlusive diseases have changed the epidemiological landscape of health problems both in developed and the developing countries. Despite the enormous benefit of advanced revascularization techniques, use of statins, and successful attempts of targeting modifiable risk factors, like smoking and exercise in the last four decades, there is still a definite "residual risk" in the population, as evidenced by many prevalent and new cases every year. Here, we highlight the burden of the atherosclerotic diseases and provide substantial clinical evidence of the residual risks in these diseases despite advanced management settings, with emphasis on strokes and cardiovascular risks. We critically discussed the concepts and potential underlying mechanisms of the evolving atherosclerotic plaques in the coronary and carotid arteries. This has changed our understanding of the plaque biology, the progression of unstable vs stable plaques, and the evolution of plaque prior to the occurrence of a major adverse atherothrombotic event. This has been facilitated using intravascular ultrasound, optical coherence tomography, and near-infrared spectroscopy in the clinical settings to achieve surrogate end points. These techniques are now providing exquisite information on plaque size, composition, lipid volume, fibrous cap thickness and other features that were previously not possible with conventional angiography.

Características clínicas asociadas a niveles elevados de lipoproteína(a) en pacientes atendidos por riesgo vascular

Objectivos

La lipoproteína(a) (Lp(a)) es cada vez más relevante en la evaluación de pacientes con riesgo vascular debido a su asociación con una mayor incidencia de eventos cardiovasculares. Este estudio tiene como objetivo identificar las características clínicas de los pacientes con niveles elevados de Lp(a) atendidos en consultas externas por riesgo vascular.

Métodos

Estudio observacional retrospectivo en donde se compararon las características clínicas de los pacientes con niveles elevados de Lp(a) (≥50 mg/dL) con la de los pacientes con valores normales (<50 mg/dL), en un total de 878 pacientes atendidos por riesgo o enfermedad vascular durante los años 2021 y 2022.

Resultados

Los valores más elevados de Lp(a) se asociaron de forma independiente con una mayor probabilidad de antecedentes de enfermedad arterial periférica (p=0,024), hipercolesterolemia familiar poligénica (HFP, p=0,030) e hipercolesterolemia familiar combinada (HFC, p=0,015), el tratamiento de inhibidores de PCSK9 (p=0,029) y la combinación de estatinas y ezetimiba (p=0,018). Sin embargo, no se obtuvieron diferencias significativas para las variables antecedentes familiares de enfermedad cardiovascular precoz (p=0,143) ni para antecedentes de enfermedad cardiovascular previa (p=0,063) a diferencia de lo identificado en otras series.

Conclusiones

Los niveles elevados de Lp(a) se asociaron con antecedentes de enfermedad arterial periférica, diagnóstico de HFP y HFC, así como con la necesidad de utilizar tratamientos hipolipemiantes más intensos.

Intracranial Aneurysms and Lipid Metabolism Disorders: From Molecular Mechanisms to Clinical Implications

Many vascular diseases are linked to lipid metabolism disorders, which cause lipid accumulation and peroxidation in the vascular wall. These processes lead to degenerative changes in the vessel, such as phenotypic transformation of smooth muscle cells and dysfunction and apoptosis of endothelial cells. In intracranial aneurysms, the coexistence of lipid plaques is often observed, indicating localized lipid metabolism disorders. These disorders may impair the function of the vascular wall or result from it. We summarize the literature on the relationship between lipid metabolism disorders and intracranial aneurysms below.

Developing an SI-traceable Lp(a) reference measurement system: a pilgrimage to selective and accurate apo(a) quantification

In the past decade a remarkable rebirth of serum/plasma lipoprotein(a) (Lp(a)) as an independent risk factor of cardiovascular disease (CVD) occurred. Updated evidence for a causal continuous association in different ethnic groups between Lp(a) concentrations and cardiovascular outcomes has been published in the latest European Atherosclerosis Society (EAS) Lp(a) consensus statement. Interest in measuring Lp(a) at least once in a person's lifetime moreover originates from the development of promising new Lp(a) lowering drugs. Accurate and clinically effective Lp(a) tests are of key importance for the timely detection of high-risk individuals and for future evaluation of the therapeutic effects of Lp(a) lowering medication. To this end, it is necessary to improve the performance and standardization of existing Lp(a) tests, as is also noted in the Lp(a) consensus statement. Consequently, a state-of-the-art internationally endorsed reference measurement system (RMS) must be in place that allows for performance evaluation of Lp(a) field tests in order to certify their validity and accuracy. An ELISA-based RMS from Northwest Lipid Research Laboratory (University of Washington, Seattle, USA) has been available since the 1990s. A next-generation apo(a)/Lp(a) RMS is now being developed by a working group from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). The envisioned apo(a) RMS is based on the direct measurement of selected proteotypic fragments generated after proteolytic digestion using quantitative protein mass spectrometry (MS). The choice for an MS-based RMS enables selective measurement of the proteotypic peptides and is by design apo(a) isoform insensitive. Clearly, the equimolar conversion of apo(a) into the surrogate peptide measurands is required to obtain accurate Lp(a) results. The completeness of proteolysis under reaction conditions from the candidate reference measurement procedure (RMP) has been demonstrated for the quantifying apo(a) peptides. Currently, the candidate apo(a) RMP is endorsed by the IFCC and recommendations for suitable secondary reference materials have been made in a recent commutability study paper. Ongoing efforts toward a complete apo(a) RMS that is listed by the Joint Committee on Traceability in Laboratory Medicine (JCTLM) are focused on the peptide-based calibration and the establishment of a network of calibration laboratories running the apo(a) RMS in a harmonized way. Once completed, it will be the holy grail for evaluation and certification of Lp(a) field methods.

High residual cardiovascular risk after lipid-lowering: prime time for Predictive, Preventive, Personalized, Participatory, and Psycho-cognitive medicine

As time has come to translate trial results into individualized medical diagnosis and therapy, we analyzed how to minimize residual risk of cardiovascular disease (CVD) by reviewing papers on "residual cardiovascular disease risk". During this review process we found 989 papers that started off with residual CVD risk after initiating statin therapy, continued with papers on residual CVD risk after initiating therapy to increase high-density lipoprotein-cholesterol (HDL-C), followed by papers on residual CVD risk after initiating therapy to decrease triglyceride (TG) levels. Later on, papers dealing with elevated levels of lipoprotein remnants and lipoprotein(a) [Lp(a)] reported new risk factors of residual CVD risk. And as new risk factors are being discovered and new therapies are being tested, residual CVD risk will be reduced further. As we move from CVD risk reduction to improvement of patient management, a paradigm shift from a reductionistic approach towards a holistic approach is required. To that purpose, a personalized treatment dependent on the individual's CVD risk factors including lipid profile abnormalities should be configured, along the line of P5 medicine for each individual patient, i.e., with Predictive, Preventive, Personalized, Participatory, and Psycho-cognitive approaches.

A Systematic Review on the Risk Modulators of Myocardial Infarction in the "Young"-Implications of Lipoprotein (a)

The presence of a myocardial infarction at a younger age is of special interest, considering the psychological and socioeconomic impact, as well as long-term morbidity and mortality. However, this group has a unique risk profile, with less traditional cardiovascular risk factors that are not well studied. This systematic review aims to evaluate traditional risk factors of myocardial infarction in the "young", highlighting the clinical implications of lipoprotein (a). We performed a comprehensive search using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) standards; we systematically searched the PubMed, EMBASE, and Science Direct Scopus databases, using the terms: "myocardial infarction", "young", "lipoprotein (a)", "low-density lipoprotein", "risk factors". The search identified 334 articles which were screened, and, at the end, 9 original research articles regarding the implications of lipoprotein (a) in myocardial infarction in the "young" were included in the qualitative synthesis. Elevated lipoprotein (a) levels were independently associated with an increased risk of coronary artery disease, especially in young patients, where this risk increased by threefold. Thus, it is recommended to measure the lipoprotein (a) levels in individuals with suspected familial hypercholesterolaemia or with premature atherosclerotic cardiovascular disease and no other identifiable risk factors, in order to identify patients who might benefit from a more intensive therapeutic approach and follow-up.

Overall and Sex-Specific Effect of Berberine for the Treatment of Dyslipidemia in Adults: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials

BACKGROUND

Berberine is a nutraceutical that can improve lipid metabolism. Berberine may also affect sex hormones and exert sex-specific lipid-modifying effects, which have been overlooked. This study aimed to comprehensively review the efficacy and safety of berberine in adults for the treatment of dyslipidemia with consideration of potential sex disparity. Data Sources We searched Medline, Embase, Wanfang, CNKI, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform from inception to 13 December 2022. No language restrictions were applied. This study was registered in PROSPERO (CRD42021293218) prior to completing the literature search. Study Selection Two blinded reviewers assessed studies for inclusion. Eligible studies were randomized controlled trials in adults that compared berberine versus placebo, and measured blood lipids or lipoproteins. Data Extraction and Synthesis Data extraction was performed by two blinded reviewers using a structured form in Covidence. Risk of bias was assessed using the Cochrane risk of bias tool for randomized trials. Mean differences (MD) were estimated using inverse variance weighting with random effects models for lipid outcomes using R. Adverse events (AEs) were described narratively. Main Outcomes Primary outcomes were low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and apolipoprotein B. Secondary outcomes were gastrointestinal and muscle-related AEs.

RESULTS

Eighteen studies (n = 1788 participants), conducted mainly in mainland China and Hong Kong (15 studies [83%]), were included with treatment durations ranging from 4 to 24 weeks. Berberine reduced LDL cholesterol (- 0.46 mmol/L, 95% CI - 0.62 to - 0.30, 14 studies, n = 1447), total cholesterol (- 0.48 mmol/L, 95% CI - 0.63 to - 0.33, 17 studies, n = 1637), triglycerides (- 0.34 mmol/L, 95% CI - 0.46 to - 0.23, 18 studies, n = 1661) and apolipoprotein B (- 0.25 g/L, 95% CI - 0.40 to - 0.11, 2 studies, n = 127). Berberine increased HDL cholesterol by 0.06 mmol/L (95% CI 0.00 to 0.11, 15 studies, n = 1471). Notably, the effect on HDL cholesterol was different in women (0.11 mmol/L, 95% CI 0.09 to 0.13) from that in men (- 0.07 mmol/L, 95% CI - 0.16 to 0.02). Among 16 studies that reported AEs, no serious AEs were reported for berberine. Gastrointestinal AEs were reported in 12 studies and tended to be more frequent in participants allocated to berberine versus placebo (2-23% vs 2-15%).

CONCLUSIONS

Berberine produces small reductions in LDL cholesterol, triglycerides, and apolipoprotein B, with potential sex-specific effects on HDL cholesterol. Large-scale trials that consider sex disparity and assess clinical outcomes are required.

A New Look at Novel Cardiovascular Risk Biomarkers: The Role of Atherogenic Lipoproteins and Innovative Antidiabetic Therapies

The presence of residual cardiovascular disease (CVD) risk is a current dilemma in clinical practice; indeed, despite optimal management and treatment, a considerable proportion of patients still undergo major CV events. Novel lipoprotein biomarkers are suggested as possible targets for improving the outcomes of patients at higher risk for CVD, and their impact on major CV events and mortality have previously been investigated. Innovative antidiabetic therapies have recently shown a significant reduction in atherogenic lipoproteins, beyond their effects on glucose parameters; it has also been suggested that such anti-atherogenic effect may represent a valuable mechanistic explanation for the cardiovascular benefit of, at least, some of the novel antidiabetic agents, such as glucagon-like peptide-1 receptor agonists. This emphasizes the need for further research in the field in order to clearly assess the effects of innovative treatments on different novel biomarkers, including atherogenic lipoproteins, such as small dense low-density lipoprotein (LDL), lipoprotein(a) (Lp(a)) and dysfunctional high-density lipoprotein (HDL). The current article discusses the clinical importance of novel lipid biomarkers for better management of patients in order to overcome residual cardiovascular risk.

Lipoprotein (a) and Cardiovascular Disease: A Missing Link for Premature Atherosclerotic Heart Disease and/or Residual Risk

ABSTRACT

Lipoprotein(a) or lipoprotein "little a" is an under-recognized causal risk factor for cardiovascular (CV) disease (CVD), including coronary atherosclerosis, aortic valvular stenosis, ischemic stroke, heart failure and peripheral arterial disease. Elevated plasma Lp(a) (≥50 mg/dL or ≥100 nmol/L) is commonly encountered in almost 1 in 5 individuals and confers a higher CV risk compared to those with normal Lp(a) levels, although such normal levels have not been generally agreed upon. Elevated Lp(a) is considered a cause of premature and accelerated atherosclerotic CVD. Thus, in patients with a positive family or personal history of premature coronary artery disease (CAD), Lp(a) should be measured. However, elevated Lp(a) may confer increased risk for incident CAD even in the absence of a family history of CAD, and even in those who have guideline-lowered LDL-cholesterol (<70 mg/dl) and continue to have a persisting CV residual risk. Thus, measurement of Lp(a) will have a significant clinical impact on the assessment of atherosclerotic CVD risk, and will assume a more important role in managing patients with CVD with the advent and clinical application of specific Lp(a)-lowering therapies. Conventional therapeutic approaches like lifestyle modification and statin therapy remain ineffective at lowering Lp(a). Newer treatment modalities, such as gene silencing via RNA interference with use of antisense oligonucleotide(s) or small interfering RNA molecules targeting Lp(a) seem very promising. These issues are herein reviewed, accumulated data are scrutinized, meta-analyses and current guidelines are tabulated and Lp(a)-related CVDs and newer therapeutic modalities are pictorially illustrated.