Lipoprotein(a) and aortic valve stenosis: A casual or causal association?

Association of lipoprotein(a) with left ventricular hypertrophy assessed by electrocardiogram in adults: a large cross-sectional study

Background and aims

Increasing evidence supports a causal relationship between lipoprotein(a) [Lp(a)] and atherosclerotic cardiovascular disease, yet its association with left ventricular hypertrophy (LVH) assessed by electrocardiogram (ECG) remains unknown. The aim of this study was to explore the relationship between Lp(a) and LVH assessed by ECG in general population.

Methods and results

In this cross-sectional study, we screened 4,052 adults from the participants of the third National Health and Nutrition Examination Survey for analysis. Lp(a) was regarded as an exposure variable. LVH defined by the left ventricular mass index estimated from ECG was considered as an outcome variable. Multivariate logistic regression and restricted cubic spline (RCS) were used to assess the relationship between Lp(a) and LVH. Individuals with LVH had higher Lp(a) compared to individuals without LVH (P< 0.001). In the fully adjusted model, Lp(a) was strongly associated with LVH when as a continuous variable (per 1-unit increment, OR: 1.366, 95% CI: 1.043-1.789, P = 0.024), and higher Lp(a) remained independently associated with a higher risk of LVH when participants were divided into four groups according to quartiles of Lp(a) (Q4 vs Q1, OR: 1.508, 95% CI: 1.185-1.918, P = 0.001). And in subgroup analysis, this association remained significant among participants< 60 years, ≥ 60 years, male, with body mass index< 30 kg/m2, with hypertension and without diabetes (P< 0.05). In addition, we did not observe a nonlinear and threshold effect of Lp(a) with LVH in the RCS analysis (P for nonlinearity = 0.113).

Conclusion

Lp(a) was closely associated with LVH assessed by ECG in general population.

Treatment of Lp(a): Is It the Future or Are We Ready Today?

PURPOSE OF REVIEW

The goal of this review is to present the pharmacodynamic effectiveness as well as the clinical efficacy and safety of investigational antisense oligonucleotides (ASOs) and small interference RNAs (siRNAs) drugs that specifically target lipoprotein(a) (Lp(a)). The review will discuss whether the existing lipid-lowering therapies are adequate to treat high Lp(a) levels or whether it is necessary to use the emerging new therapeutic approaches which are based on the current RNA technologies.

RECENT FINDINGS

Lipoprotein(a) (Lp(a)) is a causal risk factor for atherosclerotic cardiovascular disease (ASCVD), independent of other conventional risk factors. High Lp(a) levels are also independently associated with an increased risk of aortic stenosis progression rate. Plasma Lp(a) levels are primarily genetically determined by variation in the LPA gene coding for apo(a). All secondary prevention trials have demonstrated that the existing hypolipidemic therapies are not adequate to reduce Lp(a) levels to such an extent that could lead to a substantial reduction of ASCVD risk. This has led to the development of new drugs that target the mRNA transcript of LPA and efficiently inhibit Lp(a) synthesis leading to potent Lp(a) reduction. These new drugs are the ASO pelacarsen and the siRNAs olpasiran and SLN360. Recent pharmacodynamic studies showed that all these drugs potently reduce Lp(a) up to 98%, in a dose-dependent manner. Ongoing clinical trials will determine the Lp(a)-lowering efficacy, tolerability, and safety of these drugs as well as their potential effectiveness in reducing the ASCVD risk attributed to high plasma Lp(a) levels. We are not ready today to significantly reduce plasma Lp(a). Emerging therapies potently decrease Lp(a) and ongoing clinical trials will determine their effectiveness in reducing ASCVD risk in subjects with high Lp(a) levels.

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) 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.

The nonlinear correlation between lipoprotein (a) and the prevalence of aortic valve calcification in patients with new-onset acute myocardial infarction

BACKGROUND

Growing studies show that lipoprotein (a) [Lp(a)] is related to calcified aortic valve diseases in general population, while the relationship between Lp(a) and aortic valve calcification (AVC) in patients with new-onset acute myocardial infarction (AMI) remains unclear. Therefore, this study was to evaluate the correlation between Lp(a) and AVC in patients with new-onset AMI.

METHODS

This cross-sectional study included 410 patients with new-onset AMI who were hospitalised in Zhongda Hospital affiliated to Southeast University from January 1, 2020 to December 31, 2021. Multivariable logistic regression, subgroup analysis, generalised additive model, threshold and saturation effect and receiver operator characteristic (ROC) curve were used to explore the association between Lp(a) and AVC.

RESULTS

Patients with AVC had higher levels of Lp(a) than those without AVC. Multivariable logistic regression analysis showed that higher Lp(a) was still associated with higher risk of AVC after adjusting for confounding factors, and this correlation was robust in most subgroups and sensitivity analyses (p < 0.05). Additionally, the generalised additive model showed that there was a nonlinear correlation between Lp(a) and AVC (P for nonlinearity = 0.037). Threshold and saturation effect analysis indicated that when Lp(a) < 840 mg/L, it was positively correlated with the prevalence of AVC (p < 0.05), but when Lp(a) ≥ 840 mg/L, this correlation no longer existed. Besides, ROC curve analysis demonstrated that Lp(a) had a good diagnostic performance for AVC.

CONCLUSION

Lp(a) was independently associated with the prevalence of AVC in patients with new-onset AMI.

Lipoprotein Assessment in the twenty-first Century

Based on decades of both basic science and epidemiologic research, there is overwhelming evidence for the causal relationship between high levels of cholesterol, especially low-density lipoprotein cholesterol and cardiovascular disease. Risk evaluation and monitoring the response to lipid-lowering therapies are heavily dependent on the accurate assessment of plasma lipoproteins in the clinical laboratory. This article provides an update of lipoprotein metabolism as it relates to atherosclerosis and how diagnostic measures of lipids and lipoproteins can serve as markers of cardiovascular risk, with a focus on recent advances in cardiovascular risk marker testing.