Lipoprotein (a) and risk for calcification of the coronary arteries, mitral valve, and thoracic aorta: The Multi-Ethnic Study of Atherosclerosis

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genetically predicted lipoprotein(a) associates with coronary artery plaque severity independent of low-density lipoprotein cholesterol

AIMS

Elevated Lipoprotein(a) [Lp(a)] is a causal risk factor for atherosclerotic cardiovascular disease, but the mechanisms of risk are debated. Studies have found inconsistent associations between Lp(a) and measurements of atherosclerosis. We aimed to assess the relationship between Lp(a), low-density lipoprotein cholesterol (LDL-C) and coronary artery plaque severity.

METHODS

The study population consisted of participants of the Million Veteran Program who have undergone an invasive angiogram. The primary exposure was genetically predicted Lp(a), estimated by a polygenic score. Genetically predicted LDL-C was also assessed for comparison. The primary outcome was coronary artery plaque severity, categorized as normal, non-obstructive disease, 1-vessel disease, 2-vessel disease, and 3-vessel or left main disease.

RESULTS

Among 18,927 adults of genetically inferred European ancestry and 4,039 adults of genetically inferred African ancestry, we observed consistent associations between genetically predicted Lp(a) and obstructive coronary plaque, with effect sizes trending upward for increasingly severe categories of disease. Associations were independent of risk factors, clinically measured LDL-C and genetically predicted LDL-C. However, we did not find strong or consistent evidence for an association between genetically predicted Lp(a) and risk for non-obstructive plaque.

CONCLUSIONS

Genetically predicted Lp(a) is positively associated with coronary plaque severity independent of LDL-C, consistent with Lp(a) promoting atherogenesis. However, the effects of Lp(a) may be greater for progression of plaque to obstructive disease than for the initial development of non-obstructive plaque. A limitation of this study is that Lp(a) was estimated using genetic markers and could not be directly assayed, nor could apo(a) isoform size.

Osteopontin/SPP1: a potential mediator between immune cells and vascular calcification

Vascular calcification (VC) is considered a common pathological process in various vascular diseases. Accumulating studies have confirmed that VC is involved in the inflammatory response in heart disease, and SPP1+ macrophages play an important role in this process. In VC, studies have focused on the physiological and pathological functions of macrophages, such as pro-inflammatory or anti-inflammatory cytokines and pro-fibrotic vesicles. Additionally, macrophages and activated lymphocytes highly express SPP1 in atherosclerotic plaques, which promote the formation of fatty streaks and plaque development, and SPP1 is also involved in the calcification process of atherosclerotic plaques that results in heart failure, but the crosstalk between SPP1-mediated immune cells and VC has not been adequately addressed. In this review, we summarize the regulatory effect of SPP1 on VC in T cells, macrophages, and dendritic cells in different organs' VC, which could be a potential therapeutic target for VC.

Small dense low-density lipoprotein cholesterol and coronary artery calcification in the Multi-Ethnic Study of Atherosclerosis

AIMS

Elevated small dense LDL cholesterol (sd-LDL-C) increases atherosclerotic cardiovascular disease (CVD) risk. Although coronary artery calcification (CAC) is widely used for predicting CVD events, few studies have examined the relationship between sd-LDL-C and CAC.

METHODS AND RESULTS

This study included 4672 individuals with directly measured baseline sd-LDL-C and CAC from the Multi-Ethnic Study of Atherosclerosis [mean (standard deviation) age: 61.9 (10.4) years; 52.5% women; 47.3% with baseline CAC (mean score >0)]. We used multi-variable general linear models and restricted cubic splines with the goodness of fit testing to evaluate the association of sd-LDL-C with the presence of CAC. Odds ratios [OR (95% confidence interval)] were adjusted for demographics and cardiovascular risk factors, including estimated total LDL-C. Higher quartiles of sd-LDL-C were associated with the presence of CAC, even after accounting for total LDL-C. Compared with the lowest quartile of sd-LDL-C, participants in Quartiles 2, 3, and 4 had higher odds for the presence of baseline CAC [Quartile 2 OR: 1.24 (1.00, 1.53); Quartile 3 OR: 1.51 (1.19, 1.93); and Quartile 4 OR 1.59 (1.17, 2.16)]. Splines suggested a quadratic curvilinear relationship of continuous sd-LDL-C with CAC after adjustment for demographics and CVD risk factors (quadratic vs. first-order sd-LDL-C terms likelihood ratio test: P = 0.015), but not after accounting for total LDL-C (quadratic vs. first-order terms: P = 0.156).

CONCLUSION

In a large, multi-ethnic sample without known CVD, higher sd-LDL-C was associated with the presence of CAC, above and beyond total LDL-C. Whether selective direct measurement of sd-LDL-C is indicated to refine cardiovascular risk assessment in primary prevention warrants further investigation.

Subclinical Atherosclerosis to Guide Treatment in Dyslipidemia and Diabetes Mellitus

PURPOSE OF REVIEW

Dyslipidemia and type 2 diabetes mellitus are two common conditions that are associated with an increased risk of atherosclerotic cardiovascular disease (ASCVD). In this review, we aimed to provide an in-depth and contemporary review of non-invasive approaches to assess subclinical atherosclerotic burden, predict cardiovascular risk, and guide appropriate treatment strategies. We focused this paper on two main imaging modalities: coronary artery calcium (CAC) score and computed tomography coronary angiography.

RECENT FINDINGS

Recent longitudinal studies have provided stronger evidence on the relationship between increased CAC, thoracic aorta calcification, and risk of cardiovascular events among those with primary hypercholesterolemia, highlighting the beneficial role of statin therapy. Interestingly, resilient profiles of individuals not exhibiting atherosclerosis despite dyslipidemia have been described. Non-conventional markers of dyslipidemia have also been associated with increased subclinical atherosclerosis presence and burden, highlighting the contribution of apolipoprotein B-100 (apoB)-rich lipoprotein particles, such as remnant cholesterol and lipoprotein(a), to the residual risk of individuals on-target for low-density lipoprotein cholesterol (LDL-C) goals. Regarding type 2 diabetes mellitus, variability in atherosclerotic burden has also been found, and CAC testing has shown significant predictive value in stratifying cardiovascular risk. Non-invasive assessment of subclinical atherosclerosis can help reveal the continuum of ASCVD risk in those with dyslipidemia and diabetes mellitus and can inform personalized strategies for cardiovascular disease prevention in the primary prevention setting.

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.

Coronary Artery Calcification: Current Concepts and Clinical Implications

Coronary artery calcification (CAC) accompanies the development of advanced atherosclerosis. Its role in atherosclerosis holds great interest because the presence and burden of coronary calcification provide direct evidence of the presence and extent of coronary artery disease; furthermore, CAC predicts future events independently of concomitant conventional cardiovascular risk factors and to a greater extent than any other noninvasive biomarker of this disease. Nevertheless, the relationship between CAC and the susceptibility of a plaque to provoke a thrombotic event remains incompletely understood. This review summarizes the current understanding and literature on CAC. It outlines the pathophysiology of CAC and reviews laboratory, histopathological, and genetic studies, as well as imaging findings, to characterize different types of calcification and to elucidate their implications. Some patterns of calcification such as microcalcification portend increased risk of rupture and cardiovascular events and may improve prognosis assessment noninvasively. However, contemporary computed tomography cannot assess early microcalcification. Limited spatial resolution and blooming artifacts may hinder estimation of degree of coronary artery stenosis. Technical advances such as photon counting detectors and combination with nuclear approaches (eg, NaF imaging) promise to improve the performance of cardiac computed tomography. These innovations may speed achieving the ultimate goal of providing noninvasively specific and clinically actionable information.

The association of lipoprotein (a) with coronary artery calcification: A systematic review and meta-analysis

BACKGROUND AND AIMS

Coronary artery calcification (CAC) is a crucial pathophysiological characteristic of atherosclerosis. The association between lipoprotein (a) [Lp(a)] and CAC is inconsistent. We aimed to assess the relationship between Lp(a) and CAC by exploring the association between elevated Lp(a) and CAC prevalence, the relationship between Lp(a) level and CAC prevalence, and the correlation between elevated Lp(a) and CAC progression.

METHODS

We searched the PubMed, Web of Science, and EMBASE databases up to November 01, 2023. Studies exploring the association between serum Lp(a) and CAC (quantified using the Agatston score) were included. Association between Lp(a) level or elevated Lp(a) (higher than the cutoff values of 30 mg/dL, 50 mg/dL, or the highest quartile ranging from 33 to 38.64 mg/dL) and prevalence [CAC score >0 or >100, log (CAC score+1) >0] or progression (an increase in CAC score >0 or ≥100) of CAC were analysed. Odds ratios and 95% confidence intervals were calculated using a random-effects model.

RESULTS

40,073 individuals from 17 studies were included. Elevated Lp(a) was associated with a higher prevalence of CAC (OR, 1.31; 95% CI, 1.06 to 1.61; p = 0.01). As a continuous variable, Lp(a) level was positively correlated with the prevalence of CAC (OR, 1.05; 95% CI, 1.02 to 1.08; p = 0.003). Furthermore, elevated Lp(a) was associated with greater CAC progression (OR, 1.54; 95% CI, 1.23 to 1.92; p = 0.0002).

CONCLUSIONS

This meta-analysis suggested that Lp(a) is associated with prevalence and progression of CAC. Further studies are required to explore whether Lp(a)-lowering therapy could prevent or inhibit CAC, ultimately reducing coronary artery disease risk.

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

AIMS

Studies have indicated inconsistent results regarding the association between plasma levels of Lipoprotein(a) [Lp(a)] and coronary artery calcification (CAC). We performed a systematic review and meta-analysis to investigate the association between elevated levels of Lp(a) and risk of CAC in populations free of cardiovascular disease (CVD) symptoms.

DATA SYNTHESIS

PubMed, Web of Science, Embase, and Scopus were searched up to July 2022 and the methodological quality was assessed using Newcastle-Ottawa Scale (NOS) scale. Random-effects meta-analysis was used to estimate pooled odds ratio (OR) and 95% confidence interval. Out of 298 studies, data from 8 cross-sectional (n = 18,668) and 4 cohort (n = 15,355) studies were used in meta-analysis. Cohort studies demonstrated a positive significant association between Lp(a) and CAC, so that individuals with Lp(a)≥30-50 exposed to about 60% risk of CAC incidence compared to those with lower Lp(a) concentrations in asymptomatic CVD subjects (OR, 1.58; 95% CI, 1.38-1.80; l2, 0.0%; P, 0.483); Subgroup analysis showed that a cut-off level for Lp(a) measurement could not statistically affect the association, but race significantly affected the relationship between Lp(a) and CAC (OR,1.60; 95% CI, 1.41-1.81). Analyses also revealed that both men and women with higher Lp(a) concentrations are at the same risk for increased CAC.

CONCLUSIONS

Blood Lp(a) level was significantly associated with CAC incidence in asymptomatic populations with CVD, indicating that measuring Lp(a) may be a useful biomarker for diagnosing subclinical atherosclerosis in individuals at higher risk of CAC score.

PROSPERO REGISTRATION NUMBER

CRD42022350297.

Lipoprotein(a) and coronary artery calcium in comparison with other lipid biomarkers: The multi-ethnic study of atherosclerosis

BACKGROUND

Coronary artery calcium (CAC) scoring is often used for atherosclerotic cardiovascular disease (ASCVD) risk stratification in individuals with elevated lipoprotein(a) [Lp(a)].

OBJECTIVE

To evaluate associations between Lp(a) and baseline CAC (volume/density) and CAC progression compared to other lipid biomarkers.

METHODS

We utilized data from the Multi-Ethnic Study of Atherosclerosis (MESA), a cohort study of individuals without clinical ASCVD, excluding statin users. We evaluated the associations between Lp(a), low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), triglycerides, total cholesterol, apolipoprotein B, and non-HDL-C with baseline CAC and annual CAC progression using multivariable ordinal regression with adjustment for ASCVD risk factors. Analyses were also stratified by median age.

RESULTS

In 5,597 participants (2,726 at median 9.5-year follow-up), Lp(a) was not associated with baseline CAC volume or density and was modestly associated with volume progression (OR 1.11, 95% CI 1.03-1.21). However, other biomarkers were positively associated with baseline volume and volume progression (LDL-C: OR 1.26, 95% CI: 1.19-1.33 and OR 1.22, 95% CI: 1.15-1.30, respectively), except HDL-C which was inversely associated. LDL-C, total cholesterol and non-HDL-C were inversely associated with baseline density. In participants <62 years of age, Lp(a) was modestly associated with baseline CAC volume (OR 1.10, 95% CI: 1.00-1.20) and volume progression (OR 1.16 95% CI: 1.04-1.30).

CONCLUSIONS

In contrast to other lipid biomarkers, Lp(a) was not associated with baseline CAC volume or density and was only modestly associated with volume progression. Our findings suggest that Lp(a) is not as robustly associated with CAC as other lipid biomarkers.

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

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

Risk Factor Interactions, Non-High-Density Lipoprotein Cholesterol to Apolipoprotein B Ratio, and Severity of Coronary Arteriosclerosis in South Asian Individuals: An Observational Cohort Study

Background South Asian individuals are at higher risk for arteriosclerotic cardiovascular disease and diabetes. The factors associated with arteriosclerotic cardiovascular disease severity and their interactions are unknown. Methods and Results This is a retrospective cohort study of the first 1162 South Asian participants enrolled in the South Asian Heart Center's AIM to Prevent Program who completed noncontrast coronary computed tomography scans. Using machine-learning algorithms, we identified and modeled the interaction of predictor variables with coronary artery calcification (CAC) severity in South Asian individuals. Anthropometric, laboratory, demographic, and lifestyle predictor variables were analyzed using continuous boosted regression trees to model the relationship with and in between predictor variables and CAC. Participants with CAC were older, predominately men, had smoking history, had personal histories of diabetes, hypertension, and hypercholesterolemia, and had family histories of coronary artery disease. Insulin, body mass index, blood pressure, fasting blood sugar, hemoglobin A1c, and waist-to-height ratio were associated with CAC but not low-density lipoprotein cholesterol or lipoprotein (a). The arteriosclerotic cardiovascular disease score failed to classify individuals. Only age, body mass index, non-high-density lipoprotein cholesterol/apolipoprotein B ratio, smoking risk, fasting blood sugar, and diastolic blood pressure were predictive, explaining 30.3% of CAC severity. A non-high-density lipoprotein cholesterol/apolipoprotein B ratio of 1.4 or less markedly increased coronary calcification. Conclusions Our findings highlight factors associated with dysmetabolism and cholesterol-depleted non-high-density lipoprotein cholesterol particles with coronary arteriosclerosis, possibly explaining the dual epidemics of diabetes and arteriosclerotic cardiovascular disease in this population. Markers of glucose dysmetabolism and the non-high-density lipoprotein cholesterol to apolipoprotein B ratio should become the focus of assessment for cardiovascular risk in South Asian individuals, with prevention strategies directed at improving glucose metabolic health.

High lipoprotein(a) levels and mitral valve disease: A systematic review

AIMS

The role of lipoprotein(a) [Lp(a)] as a possibly causal risk factor for atherosclerotic artery disease and aortic valve stenosis has been well established. However, the information available on the association between Lp(a) levels and mitral valve disease is limited and controversial. The main objective of the present study was to assess the association between Lp(a) levels and mitral valve disease.

DATA SYNTHESIS

This systematic review was performed according to PRISMA guidelines (PROSPERO CRD42022379044). A literature search was performed to detect studies that evaluated the association between Lp(a) levels or single-nucleotide polymorphisms (SNPs) related to high levels of Lp(a) and mitral valve disease, including mitral valve calcification and valve dysfunction. Eight studies including 1,011,520 individuals were considered eligible for this research. The studies that evaluated the association between Lp(a) levels and prevalent mitral valve calcification found predominantly positive results. Similar findings were reported in two studies that evaluated the SNPs related to high levels of Lp(a). Only two studies evaluated the association of Lp(a) and mitral valve dysfunction, showing contradictory results.

CONCLUSIONS

This research showed disparate results regarding the association between Lp(a) levels and mitral valve disease. The association between Lp(a) levels and mitral valve calcification seems more robust and is in line with the findings already demonstrated in aortic valve disease. New studies should be developed to clarify this topic.

Relationship of fibroblast growth factor 21 with the prevalence and progression of vascular and valvular calcification: Multi-ethnic study of atherosclerosis

BACKGROUND

Elevated circulating levels of fibroblast growth factor 21 (FGF21) are associated with cardiovascular disease (CVD). Therefore, we investigated the relationship of plasma FGF21 with calcification at different vascular and valvular sites.

METHODS

A total of 5786 participants, free of clinically apparent CVD at baseline and with valid data on plasma FGF21 and calcification (Agatston score, volume and density) at coronary arteries, thoracic arteries, mitral and aortic valves, and aortic valve ring, were included in the analysis. Vascular calcification was measured at 2-3 follow-up visits.

RESULTS

At baseline, higher FGF21 levels were associated with prevalent descending thoracic aortic calcification (DTAC) (prevalence ratio = 1.06 [95% CI 1.01-1.11] per SD increase in log-transformed unit, P = 0.016). Among participants without prevalent calcification, higher FGF21 levels were associated with incident DTAC (relative risk [RR] = 1.13 [95% CI 1.04-1.22], P = 0.002). Among all participants, higher FGF21 levels were also associated with the progression of DTAC score and volume (RR = 1.07 [95% CI 1.03-1.12] and 1.08 [95% CI 1.03-1.12] respectively, both P < 0.01). No significant association of FGF21 was found for prevalence (prevalence ratio = 0.89-1.05), incidence (RR = 0.97-1.16) and progression of calcification (RR = 0.94-1.14) at the other sites.

CONCLUSION

Higher FGF21 levels were associated with the presence, incidence and progression of DTAC. However, the magnitude of this association was similar to those of the non-significant associations of FGF21 levels with calcifications at other sites. Further research is needed to assess the potential of FGF21 as a biomarker for vascular calcification.

Cardiovascular risk-enhancing factors and coronary artery calcium in South Asian American adults: The MASALA study

Objectives

The 2018 and 2019 U.S. guidelines for the management of cholesterol and primary prevention of atherosclerotic cardiovascular disease (ASCVD) recommend consideration of cardiovascular risk-enhancing factors (REFs), including South Asian ancestry, to refine ASCVD risk estimation. However, the associations of REFs with atherosclerosis are unclear in South Asian American adults, who have a disproportionately elevated premature coronary heart disease risk. In the Mediators of Atherosclerosis in South Asians Living in America (MASALA) cohort, we investigated associations of individual REFs, or the number of REFs, with coronary artery calcium (CAC).

Methods

Using baseline and follow-up data from MASALA, we evaluated the association of REFs (family history of ASCVD, low-density lipoprotein cholesterol ≥160 mg/dL, triglycerides ≥175 mg/dL, lipoprotein(a) >50 mg/dL, high-sensitivity C-reactive protein [hsCRP] ≥2.0 mg/dL, ankle-brachial index <0.9, chronic kidney disease, metabolic syndrome), individually and combined, with baseline prevalent CAC, any CAC progression (including incident CAC and CAC progression), and annual CAC progression rates using multivariable logistic regression and generalized linear models.

Results

Among 866 adults, mean age was 55 [SD 9] years and 47% were female. There were no significant associations of REFs with baseline prevalent CAC or any CAC progression (incident CAC and CAC progression at Exam 2) after adjustment. Among the 56% of participants who had any CAC progression, having 3+ REFs was associated with a significantly higher annual CAC progression rate (adjusted rate ratio [aRR] 1.94, 95% CI 1.39-2.72) vs. having 0 REFs. The annual CAC progression rate was 20% higher per additional REF (aRR 1.20, 95% CI 1.09-1.32). Findings were similar after excluding statin users, and among those with low 10-year ASCVD risk (<5%).

Conclusions

Among South Asian American adults, we found no association of REFs with prevalent CAC at baseline or having any CAC progression. Among those with any CAC progression, a higher number of REFs was associated with higher annual CAC progression rates.

Lipoprotein(a): Cardiovascular Disease, Aortic Stenosis and New Therapeutic Option

Atherosclerosis is a chronic and progressive inflammatory process beginning early in life with late clinical manifestation. This slow pathological trend underlines the importance to early identify high-risk patients and to treat intensively risk factors to prevent the onset and/or the progression of atherosclerotic lesions. In addition to the common Cardiovascular (CV) risk factors, new markers able to increase the risk of CV disease have been identified. Among them, high levels of Lipoprotein(a)-Lp(a)-lead to very high risk of future CV diseases; this relationship has been well demonstrated in epidemiological, mendelian randomization and genome-wide association studies as well as in meta-analyses. Recently, new aspects have been identified, such as its association with aortic stenosis. Although till recent years it has been considered an unmodifiable risk factor, specific drugs have been developed with a strong efficacy in reducing the circulating levels of Lp(a) and their capacity to reduce subsequent CV events is under testing in ongoing trials. In this paper we will review all these aspects: from the synthesis, clearance and measurement of Lp(a), through the findings that examine its association with CV diseases and aortic stenosis to the new therapeutic options that will be available in the next years.

Atherogenic index of plasma is an independent predictor of mitral annular calcification

BACKGROUND

In the latest reports, atherogenic indices have been related to acute coronary syndromes, stable coronary artery disease, heart failure and future cardiac events. Conventional atherosclerosis risk factors have been associated with mitral annular calcification (MAC), but data on the relationship between atherogenic indices and MAC are lacking. We aimed to investigate a possible relationship between MAC and atherogenic indices.

METHODS

In total 741 patients (n = 427 with MAC and n = 314 without MAC) who were examined in our cardiology clinic from February 2016 to October 2021 were recruited in the study. Mitral annular calcification was diagnosed by transthoracic 2-dimensional echocardiography. The atherogenic coefficient (AC), Castelli risk index 1 (CRI-1), Castelli risk index 2 (CRI-2) and atherogenic index of plasma (AIP) were calculated by utilizing standard lipid test values.

RESULTS

There was no statistically significant difference in sex, age, diabetes and hypertension status between the patient and the control groups. Serum triglyceride level, AIP, Hs-CRP, smoking and BMI were independently significantly associated with MAC in multiple regression analysis (p < 0.001).

CONCLUSION

Higher AIP was related to the existence of MAC and also predict the presence of MAC independently. Studies evaluating the modification of these indices are needed.

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.

Coronary artery calcium incidence and changes using direct plaque measurements: The MASALA study

BACKGROUND AND AIMS

We aimed to identify predictors of change in direct measures of coronary artery calcium (CAC) volume and density in South Asian participants.

METHODS

We used data from participants in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study with prevalent CAC and direct measures of CAC by serial computed tomography (CT) exams (2010-2013, 2016-2018). We examined the distribution of incident CAC volume and peak density, as well as progression and identified risk factors for progression of change in volume and density in multivariable models.

RESULTS

The study cohort consisted of 102 participants with incident CAC and 285 with CAC progression. CAC volume and density were highest, and incident CAC was most common in the left anterior descending artery (LAD). The greatest progression in volume was in the right coronary artery and the greatest change in density was in the left main. In linear regression models for CAC progression adjusted for baseline density, volume, risk factors, smoking (β +190.1, p = 0.02), baseline volume (β +0.24 per mm³, p < 0.01), and scan interval (β +0.15 per day, p = 0.01) were associated with change in total volume whereas Lp(a) (β +0.81 per mg/dL, p = 0.03), exercise (β +0.19 per 10 MET-min/week, p = 0.01), and baseline volume (β +0.15 per mm³, p < 0.01) and density (β -0.55 per unit, p < 0.01) were associated with change in total density.

CONCLUSIONS

In this South Asian cohort, smoking was associated with CAC volume progression, while Lp(a) and exercise were associated with progression of peak CAC density.

Lipoprotein(a) and Subclinical Vascular and Valvular Calcification on Cardiac Computed Tomography: The Atherosclerosis Risk in Communities Study

Background Lipoprotein(a) (Lp(a)) is a potent causal risk factor for cardiovascular events and mortality. However, its relationship with subclinical atherosclerosis, as defined by arterial calcification, remains unclear. This study uses the ARIC (Atherosclerosis Risk in Communities Study) to evaluate the relationship between Lp(a) in middle age and measures of vascular and valvular calcification in older age. Methods and Results Lp(a) was measured at ARIC visit 4 (1996-1998), and coronary artery calcium (CAC), together with extracoronary calcification (including aortic valve calcium, aortic valve ring calcium, mitral valve calcification, and thoracic aortic calcification), was measured at visit 7 (2018-2019). Lp(a) was defined as elevated if >50 mg/dL and CAC/extracoronary calcification were defined as elevated if >100. Logistic and linear regression models were used to evaluate the association between Lp(a) and CAC/extracoronary calcification, with further stratification by race. The mean age of participants at visit 4 was 59.2 (SD 4.3) years, with 62.2% women. In multivariable adjusted analyses, elevated Lp(a) was associated with higher odds of elevated aortic valve calcium (adjusted odds ratio [aOR], 1.82; 95% CI, 1.34-2.47), CAC (aOR, 1.40; 95% CI, 1.08-1.81), aortic valve ring calcium (aOR, 1.36; 95% CI, 1.07-1.73), mitral valve calcification (aOR, 1.37; 95% CI, 1.06-1.78), and thoracic aortic calcification (aOR, 1.36; 95% CI, 1.05-1.77). Similar results were obtained when Lp(a) and CAC/extracoronary calcification were examined on continuous logarithmic scales. There was no significant difference in the association between Lp(a) and each measure of calcification by race or sex. Conclusions Elevated Lp(a) at middle age is significantly associated with vascular and valvular calcification in older age, represented by elevated CAC, aortic valve calcium, aortic valve ring calcium, mitral valve calcification, thoracic aortic calcification. Our findings encourage assessing Lp(a) levels in individuals with increased cardiovascular disease risk, with subsequent comprehensive vascular and valvular assessment where elevated.

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.

The Journal of cardiovascular computed tomography: A year in review 2021

This review aims to summarize original articles published in the Journal of Cardiovascular Computed Tomography (JCCT) for the year 2021, focusing on those that had the most scientific and educational impact. The JCCT continues to expand; the number of submissions, published manuscripts, cited articles, article downloads, social media presence, and impact factor continues to increase. The articles selected by the Editorial Board of the JCCT in this review focus on coronary artery disease, coronary physiology, structural heart disease, and technical advances in cardiovascular CT. In addition, we highlight key consensus documents and guidelines published in the Journal in 2021. The Journal recognizes the tremendous work done by each author and reviewer this year - thank you.

Independent Association of Lipoprotein(a) and Coronary Artery Calcification With Atherosclerotic Cardiovascular Risk

BACKGROUND

Elevated lipoprotein(a) [Lp(a)] and coronary artery calcium (CAC) score are individually associated with increased atherosclerotic cardiovascular disease (ASCVD) risk but have not been studied in combination.

OBJECTIVES

This study sought to investigate the independent and joint association of Lp(a) and CAC with ASCVD risk.

METHODS

Plasma Lp(a) and CAC were measured at enrollment among asymptomatic participants of the MESA (Multi-Ethnic Study of Atherosclerosis) (n = 4,512) and DHS (Dallas Heart Study) (n = 2,078) cohorts. Elevated Lp(a) was defined as the highest race-specific quintile, and 3 CAC score categories were studied (0, 1-99, and ≥100). Associations of Lp(a) and CAC with ASCVD risk were evaluated using risk factor-adjusted Cox regression models.

RESULTS

Among MESA participants (61.9 years of age, 52.5% women, 36.8% White, 29.3% Black, 22.2% Hispanic, and 11.7% Chinese), 476 incident ASCVD events were observed during 13.2 years of follow-up. Elevated Lp(a) and CAC score (1-99 and ≥100) were independently associated with ASCVD risk (HR: 1.29; 95% CI: 1.04-1.61; HR: 1.68; 95% CI: 1.30-2.16; and HR: 2.66; 95% CI: 2.07-3.43, respectively), and Lp(a)-by-CAC interaction was not noted. Compared with participants with nonelevated Lp(a) and CAC = 0, those with elevated Lp(a) and CAC ≥100 were at the highest risk (HR: 4.71; 95% CI: 3.01-7.40), and those with elevated Lp(a) and CAC = 0 were at a similar risk (HR: 1.31; 95% CI: 0.73-2.35). Similar findings were observed when guideline-recommended Lp(a) and CAC thresholds were considered, and findings were replicated in the DHS.

CONCLUSIONS

Lp(a) and CAC are independently associated with ASCVD risk and may be useful concurrently for guiding primary prevention therapy decisions.

Elevated lipoprotein(a) in mitral and aortic valve calcification and disease: The Copenhagen General Population Study

BACKGROUND AND AIMS

We tested the hypotheses (i) that elevated lipoprotein(a) is causally associated with both mitral and aortic valve calcification and disease, and (ii) that aortic valve calcification mediates the effect of elevated lipoprotein(a) on aortic valve stenosis.

METHODS

From the Copenhagen General Population study, we included 12,006 individuals who underwent cardiac computed tomography to measure mitral and aortic valve calcification and 85,884 to examine risk of heart valve disease. Participants had information on plasma lipoprotein(a) and genetic instruments associated with plasma lipoprotein(a) to investigate potential causality.

RESULTS

At age 70-79 years, 29% and 54% had mitral and aortic valve calcification, respectively. For 10-fold higher lipoprotein(a) levels, multifactorially adjusted odds ratios for mitral and aortic valve calcification were 1.26 (95% confidence interval: 1.13-1.41) and 1.62 (1.48-1.77). For mitral and aortic valve stenosis, corresponding hazard ratios were 0.93 (95%CI:0.40-2.15, 19 events) and 1.54 (1.38-1.71, 1158 events), respectively. For ≤23 versus ≥36 kringle IV type 2 number of repeats, the age and sex adjusted odds ratios for mitral and aortic valve calcification were 1.53 (1.18-1.99) and 2.23 (1.81-2.76). For carriers versus non-carriers of LPA rs10455872, odds ratios for mitral and aortic valve calcification were 1.33 (1.13-1.57) and 1.86 (1.64-2.13). For aortic valve stenosis, 31% (95%CI:16%-76%) of the effect of lipoprotein(a) was mediated through calcification.

CONCLUSIONS

Elevated lipoprotein(a) was genetically and observationally associated with mitral and aortic valve calcification and aortic valve stenosis. Aortic valve calcification mediated 31% of the effect of elevated lipoprotein(a) on aortic valve stenosis.

Elevated Lipoprotein(a): Background, Current Insights and Future Potential Therapies

Lipoprotein(a) forms a subfraction of the lipid profile and is characterized by the addition of apolipprotein(a) (apo(a)) to apoB100 derived particles. Its levels are mostly genetically determined inversely related to the number of protein domain (kringle) repeats in apo(a). In epidemiological studies, it shows consistent association with cardiovascular disease (CVD) and most recently with extent of aortic stenosis. Issues with standardizing the measurement of Lp(a) are being resolved and consensus statements favor its measurement in patients at high risk of, or with family histories of CVD events. Major lipid-lowering therapies such as statin, fibrates, and ezetimibe have little effect on Lp(a) levels. Therapies such as niacin or cholesterol ester transfer protein (CETP) inhibitors lower Lp(a) as well as reducing other lipid-related risk factors but have failed to clearly reduce CVD events. Proprotein convertase subtilisin kexin-9 (PCSK9) inhibitors reduce cholesterol and Lp(a) as well as reducing CVD events. New antisense therapies specifically targeting apo(a) and hence Lp(a) have greater and more specific effects and will help clarify the extent to which intervention in Lp(a) levels will reduce CVD events.

Lipoprotein (a) and coronary artery calcification: prospective study assessing interactions with other risk factors

BACKGROUND

Elevated plasma lipoprotein (a) [Lp(a)] and coronary artery calcification (CAC) are established cardiovascular risk factors that correlate with each other. We hypothesized that other cardiovascular risk factors could affect their relationship.

METHODS

We tested for interactions of 24 study variables related to dyslipidemia, diabetes, insulin resistance, hypertension, inflammation and coagulation with baseline Lp(a) on change in CAC volume and density over 9.5 years in 5975 Multi-Ethnic Study of Atherosclerosis (MESA) participants, free of apparent cardiovascular disease at baseline.

RESULTS

Elevated Lp(a) was associated with larger absolute increase in CAC volume (3.21 and 4.45 mm3/year higher for Lp(a) ≥30 versus <30 mg/dL, and Lp(a) ≥50 versus <50 mg/dL, respectively), but not relative change in CAC volume. No association was found with change in CAC density when assessing continuous ln-transformed Lp(a). The association between elevated Lp(a) (≥30 mg/dL) and absolute change in CAC volume was greater in participants with higher circulating levels of interleukin-2 soluble receptor α, soluble tumor necrosis factor alpha receptor 1 and fibrinogen (15.33, 11.81 and 7.02 mm3/year in quartile 4, compared to -3.44, -0.59 and 1.91 mm3/year in quartile 1, respectively). No significant interaction was found for other study variables. Similar interactions were seen when assessing Lp(a) levels ≥50 mg/dL.

CONCLUSIONS

Elevated Lp(a) was associated with an absolute increase in CAC volume, especially in participants with higher levels of selected markers of inflammation and coagulation. These results suggest Lp(a) as a potential biomarker for CAC volume progression.