Predictive value of lipoprotein(a) in coronary artery calcification among asymptomatic cardiovascular disease subjects: A systematic review and meta-analysis

The Association between Lipoprotein(a) and Coronary Artery Calcification in Elderly Patients with Diabetes: A Cross-Sectional Study

Background

Lipoprotein(a) [Lp(a)] is associated with the development of coronary artery calcification (CAC), yet its exact function is not fully understood. This study sought to assess the relationship between Lp(a) levels and the risk of CAC in elderly diabetic patients.

Methods

This cross-sectional study included 486 elderly diabetic patients. The exposure factor was Lp(a) levels, categorized into three groups (T1, T2, T3). The outcome was the presence of CAC. The relationship between Lp(a) levels and CAC was evaluated using several statistical methods, including univariate and multivariate logistic regression, multivariable stratified analysis, receiver operating characteristic (ROC) curve analysis, and restricted cubic spline (RCS) analysis.

Results

The highest Lp(a) group (T3) showed significantly higher prevalence of CAC compared to the T1 and T2 groups. Univariate logistic regression indicated a significant link between Lp(a) and CAC. Furthermore, multivariate logistic regression supported the finding that elevated Lp(a) levels correlated with a heightened risk of CAC in all models. Specifically, each unit rise in Lp(a) was associated with a notable increase in CAC risk, and Log10Lp(a) and each 1 standard deviation increase in Lp(a) also significantly elevated CAC risk. Multivariable stratified analysis demonstrated significant differences in CAC risk across various subgroups, including age ≤70 years, males, females, smokers, hypertensive, non-hypertensive, hyperlipidemic, non-hyperlipidemic, non-stroke, and non-chronic kidney disease patients. ROC curve analysis showed that adding Lp(a) to the baseline model improved the area under the curve from 0.741 to 0.755. RCS analysis indicated a significant, approximately linear association between Log10Lp(a) and CAC risk (p nonlinear = 0.115).

Conclusions

In an elderly diabetic population, elevated levels of Lp(a) were strongly linked to a greater risk of CAC. Integrating Lp(a) measurements with conventional risk factors improves the predictive accuracy for CAC.

Novel Circulating Biomarkers in Aortic Valve Stenosis

The underlying pathophysiology of aortic stenosis and factors affecting its clinical progression remain poorly understood. Apart from B-type natriuretic peptide (BNP), novel and emerging biomarkers have been described in association with aortic stenosis, emphasising the potential for these biomarkers to illuminate on yet unknown mechanisms of its pathogenesis. In this review, we aimed to summarise what is known about aortic stenosis biomarkers, highlight the emerging ones, and provide a roadmap for translating these insights into clinical applications. Among the biomarkers studied, lipoprotein(a) [Lp(a)] has emerged as the most promising for risk stratification. Elevated Lp(a) levels are often associated with more rapid aortic stenosis progression. This detrimental effect is attributed to its role in promoting valve calcification. While other emerging biomarkers such as matrix metalloproteinases, monocytes, and metabolites show promises, their specific roles in aortic stenosis pathophysiology remain less clear. This may be due to their relatively recent discovery. Ongoing research aims to elucidate their mechanisms of action.

Coronary Artery Calcium Scoring in the Context of Widespread Lipoprotein(a) Testing: Clinical Considerations and Implications for Lipid-Lowering Therapies

PURPOSE OF REVIEW

This review evaluates the interplay between lipoprotein(a) [Lp(a)] and coronary artery calcium (CAC) for risk prediction and preventive therapy selection, with a special emphasis on scenarios where these measures are discordant, particularly in otherwise intermediate-risk, primary prevention patients.

RECENT FINDINGS

Observational studies and meta-analyses indicate a nuanced relationship between elevated Lp(a) levels and CAC burden and progression. Elevated Lp(a) is associated with an increased risk of CAC presence and progression; although, there is notable variability across studies. CAC predicts a similarly elevated risk in patients with low and high Lp(a). Joint elevation of Lp(a) and CAC is associated with a very high-risk patient subset. Elevated Lp(a) should prompt consideration of CAC testing for further risk stratification. In the future, we anticipate that an elevated CAC score could prompt consideration of testing for Lp(a) in select patients, as identifying or confirming elevated Lp(a) may help guide the use of dedicated Lp(a)-lowering therapies in very high-risk primary prevention populations.

The functions of apolipoproteins and lipoproteins in health and disease

Lipoproteins and apolipoproteins are crucial in lipid metabolism, functioning as essential mediators in the transport of cholesterol and triglycerides and being closely related to the pathogenesis of multiple systems, including cardiovascular. Lipoproteins a (Lp(a)), as a unique subclass of lipoproteins, is a low-density lipoprotein(LDL)-like particle with pro-atherosclerotic and pro-inflammatory properties, displaying high heritability. More and more strong evidence points to a possible link between high amounts of Lp(a) and cardiac conditions like atherosclerotic cardiovascular disease (ASCVD) and aortic stenosis (AS), making it a risk factor for heart diseases. In recent years, Lp(a)'s role in other diseases, including neurological disorders and cancer, has been increasingly recognized. Although therapies aimed at low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) have achieved significant success, elevated Lp(a) levels remain a significant clinical management problem. Despite the limited efficacy of current lipid-lowering therapies, major clinical advances in new Lp(a)-lowering therapies have significantly advanced the field. This review, grounded in the pathophysiology of lipoproteins, seeks to summarize the wide-ranging connections between lipoproteins (such as LDL-C and HDL-C) and various diseases, alongside the latest clinical developments, special emphasis is placed on the pivotal role of Lp(a) in cardiovascular disease, while also examining its future potential and mechanisms in other conditions. Furthermore, this review discusses Lp(a)-lowering therapies and highlights significant recent advances in emerging treatments, advocates for further exploration into Lp(a)'s pathogenic mechanisms and its potential as a therapeutic target, proposing new secondary prevention strategies for high-risk individuals.

The association of lipoprotein(a) and coronary artery calcium in asymptomatic patients: a systematic review and meta-analysis

AIMS

Lipoprotein(a) [Lp(a)] is an atherogenic lipid particle associated with increased risk for coronary heart disease (CHD) events. Coronary artery calcium (CAC) score is a tool to diagnose subclinical atherosclerosis and guide clinical decision-making for primary prevention of CHD. Studies show conflicting results concerning the relationship between Lp(a) and CAC in asymptomatic populations. We conducted a meta-analysis to evaluate the association of Lp(a) and CAC in asymptomatic patients.

METHODS AND RESULTS

We systematically searched PubMed, Embase, and Cochrane until April 2023 for studies evaluating the association between Lp(a) and CAC in asymptomatic patients. We evaluated CAC > 0 Agatston units, and CAC ≥ 100. Lp(a) was analysed as a continuous or dichotomous variable. We assessed the association between Lp(a) and CAC with pooled odds ratios (OR) adopting a random-effects model. A total of 23 105 patients from 18 studies were included in the meta-analysis with a mean age of 55.9 years, 46.4% female. Elevated Lp(a) increased the odds of CAC > 0 [OR 1.31; 95% confidence intervals (CI) 1.05-1.64; P = 0.02], CAC ≥100 (OR 1.29; 95% CI 1.01-1.65; P = 0.04; ), and CAC progression (OR 1.43; 95% CI 1.20-1.70; P < 0.01; ). For each increment of 1 mg/dL in Lp(a) there was a 1% in the odds of CAC > 0 (OR 1.01; 95% CI 1.01-1.01; P < 0.01).

CONCLUSION

Our findings of this meta-analysis suggest that Lp(a) is positively associated with a higher likelihood of CAC. Higher Lp(a) levels increased the odds of CAC >0. These data support the concept that Lp(a) is atherogenic, although with high heterogeneity and a low level of certainty.

PROTOCOL REGISTRATION

CRD42023422034.

KEY FINDINGS

Asymptomatic patients with elevated Lp(a) had 31% higher chances of having any coronary calcification (CAC > 0) and 29% higher chances of having more advanced calcification (CAC > 100). It increased the chances of having progression of coronary calcification over time by 43%. For each 1 mg/dL of Lp(a) there was an increment of 1% chance of having coronary calcification.

The association between C-reactive protein and coronary artery calcification: a systematic review and meta-analysis

BACKGROUND

While coronary artery calcification (CAC) is recognized as a reliable marker for coronary atherosclerosis, the relationship between the concentration of C-reactive protein (CRP) and the incidence and progression of CAC remains controversial.

METHOD

PubMed, Embase, Web of Science, and Scopus were systematically searched to identify relevant observational studies until October 2023. The methodological quality of the included studies was evaluated using the Newcastle-Ottawa Scale (NOS). A random-effects meta-analysis was employed to calculate pooled odd ratios (OR) and corresponding 95% confidence intervals, considering heterogeneity among the studies.

RESULTS

Out of the 2545 records, 42 cross-sectional and 9 cohort studies were included in the systematic review. The meta-analysis on 12 eligible cross-sectional studies revealed no significant association between CAC and CRP [pooled OR: 1.03 (1.00, 1.06)]. Additionally, an insignificant association was found between CAC and CRP through meta-analysis on three eligible cohort studies [pooled OR: 1.05 (0.95, 1.15)] with no considerable heterogeneity across studies. Sensitivity analyses indicated that the meta-analysis models were robust. There was no evidence of publication bias.

CONCLUSION

Based on the meta-analysis findings, elevated levels of CRP did not emerge as a valuable prognostic maker for CAC incidence and progression prediction.

Assessment of Apolipoprotein(a) Isoform Size Using Phenotypic and Genotypic Methods

Apolipoprotein(a) (apo(a)) is the protein component that defines lipoprotein(a) (Lp(a)) particles and is encoded by the LPA gene. The apo(a) is extremely heterogeneous in size due to the copy number variations in the kringle-IV type 2 (KIV2) domains. In this review, we aim to discuss the role of genetics in establishing Lp(a) as a risk factor for coronary heart disease (CHD) by examining a series of molecular biology techniques aimed at identifying the best strategy for a possible application in clinical research and practice, according to the current gold standard.