Lack of association of lipoprotein(a) levels with coronary calcium deposits in asymptomatic postmenopausal women

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.

Coronary calcification is associated with elevated serum lipoprotein (a) levels in asymptomatic men over the age of 45 years: A cross-sectional study of the Korean national health checkup data

Lipoprotein a (Lp (a)) and coronary artery calcification (CAC) are markers of coronary artery and cardiovascular diseases. However, the association between Lp (a) and CAC in asymptomatic individuals remains unclear. In this study, we aimed to determine the influence of Lp (a) on CAC in asymptomatic individuals.We included 2019 asymptomatic Korean adults who underwent testing for a coronary artery calcium score (CACS) and Lp (a) at the Gangnam Severance Hospital Health Checkup Center in Korea from January 2017 to August 2019. Participants were divided into 2 groups: CACS = 0 and CACS > 0. Factors affecting the CACS were analyzed by sex. Because age is a major risk factor for atherosclerosis, ≥45 years in men and ≥55 years in women, we further divided participants into 4 subgroups (≥45 and <45 in men, ≥55 and <55 in women). Factors affecting the CACS in the 4 groups were analyzed.There was a positive correlation between the CACS and traditional cardiovascular risk factors. Lp (a) positively correlated with the CACS in men (P < .01) and remained significant after multivariable logistic regression (P < .01). The same result was observed in men aged ≥45 years (P < .01).Lp (a) is an independently associated factor of CAC and a marker of coronary atherosclerosis in asymptomatic men aged ≥45 years. In asymptomatic men aged ≥45 years, Lp (a) should be measured, and intensive Lp (a)-lowering treatment should be considered.

Race-Based Differences in Lipoprotein(a)-Associated Risk of Carotid Atherosclerosis

Objective- Lp(a) [lipoprotein(a)] is a well-described risk factor for atherosclerosis, but Lp(a)-associated risk may vary by race/ethnicity. We aimed to determine whether race/ethnicity modifies Lp(a)-related risk of carotid atherosclerotic plaque outcomes among black, white, Chinese, and Hispanic individuals. Approach and Results- Carotid plaque presence and score were assessed by ultrasonography at baseline (n=5155) and following a median 9.4 year period (n=3380) in MESA (Multi-Ethnic Study of Atherosclerosis) participants. Lp(a) concentrations were measured by immunoassay and examined as a continuous and categorical variable using clinically-based cutoffs, 30 and 50 mg/dL. Lp(a) was related to greater risk of prevalent carotid plaque at baseline in whites alone (all P<0.001): per log unit (relative risk, 1.05); Lp(a)≥30 mg/dL (relative risk, 1.16); and Lp(a)≥50 mg/dL (relative risk, 1.20). Lp(a) levels over 50 mg/dL were associated with a higher plaque score at baseline in whites (all P<0.001) and Hispanics ( P=0.04). In prospective analyses, whites with Lp(a) ≥50 mg/dL were found to have greater risk of plaque progression (relative risk, 1.12; P=0.03) and higher plaque scores (all P<0.001) over the 9.4-year follow-up. Race-based differences between whites and black participants were significant for cross-sectional associations and for carotid plaque score following the 9.4 year study period. Conclusions- Race was found to be a modifying variable in Lp(a)-related risk of carotid plaque, and Lp(a) levels may have greater influence on plaque burden in whites than in black individuals. Borderline results in Hispanics suggest that elevated Lp(a) may increase the risk of carotid plaque, but follow-up studies are needed.

Lipoprotein(a) in postmenopausal women: assessment of cardiovascular risk and therapeutic options

INTRODUCTION

Lipoprotein(a) [Lp(a)], a low-density lipoprotein (LDL)-like particle, has been independently associated with increased cardiovascular disease (CVD) risk in various populations, such as postmenopausal women. The purpose of this narrative review is to present current data on the role of Lp(a) in augmenting CVD risk in postmenopausal women and focus on the available therapeutic strategies.

METHODS

PubMed was searched for English language publications until November 2015 under the following terms: "therapy" OR "treatment" AND ["lipoprotein (a)" OR "Lp(a)"] AND ("postmenopausal women" OR "menopausal women" OR "menopause").

RESULTS

Only hormone replacement therapy (mainly oral estrogens) and tibolone have been specifically studied in postmenopausal women and can reduce Lp(a) concentrations by up to 44%, although evidence indicating a concomitant reduction in CVD risk associated with Lp(a) is lacking. As alternative treatments for women who cannot, or will not, take hormonal therapies, niacin and the upcoming proprotein convertase subtilisin / kexin type 9 (PCSK-9) inhibitors are effective in reducing Lp(a) concentrations by up to 30%. Statins have minimal or no effect on Lp(a). However, data for these and other promising Lp(a)-lowering therapies including mipomersen, lomitapide, cholesterol-ester-transfer protein inhibitors and eprotirome are derived from studies in the general, mainly high CVD risk, population, and include only subpopulations of postmenopausal women.

CONCLUSIONS

Past, present and emerging therapies can reduce Lp(a) concentrations to a varying extent. Overall, it remains to be proven whether the aforementioned reductions in Lp(a) by these therapeutic options are translated into CVD risk reduction in postmenopausal women.

Lipoprotein(a) Levels Are Associated With Subclinical Calcific Aortic Valve Disease in White and Black Individuals: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Lipoprotein(a) [Lp(a)] is a risk factor for calcific aortic valve disease (CAVD) but has not been evaluated across multiple races/ethnicities. This study aimed to determine whether Lp(a) cutoff values used in clinical laboratories to assess risk of cardiovascular disease identify subclinical CAVD and its severity and whether significant relations are observed across race/ethnicity.

APPROACH AND RESULTS

Lp(a) concentrations were measured using a turbidimetric immunoassay, and subclinical CAVD was measured by quantifying aortic valve calcification (AVC) through computed tomographic scanning in 4678 participants of the Multi-Ethnic Study of Atherosclerosis. Relative risk and ordered logistic regression analysis determined cross-sectional associations of Lp(a) with AVC and its severity, respectively. The conventional 30 mg/dL Lp(a) clinical cutoff was associated with AVC in white (relative risk: 1.56; confidence interval: 1.24-1.96) and was borderline significant (P=0.059) in black study participants (relative risk: 1.55; confidence interval: 0.98-2.44). Whites with levels ≥50 mg/dL also showed higher prevalence of AVC (relative risk: 1.72; confidence interval: 1.36-2.17) than those below this level. Significant associations were observed between Lp(a) and degree of AVC in both white and black individuals. The presence of existing coronary artery calcification did not affect these associations of Lp(a) and CAVD. There were no significant findings in Hispanics or Chinese.

CONCLUSIONS

Lp(a) cutoff values that are currently used to assess cardiovascular risk seem to be applicable to CAVD, but our results suggest race/ethnicity may be important in cutoff selection. Further studies are warranted to determine whether race/ethnicity influences Lp(a) and risk of CAVD incidence and its progression.

Self-reported and accelerometer-derived physical activity levels and coronary artery calcification progression in older women: results from the Healthy Women Study

OBJECTIVE

Despite the well-supported biological link between physical activity (PA) and atherosclerosis, most previous studies have reported a null association between PA and coronary artery calcification (CAC). The aim of this study was to examine the relationship between PA and CAC progression in 148 Healthy Women Study (HWS) participants over 28 years of observation.

METHODS

The HWS was designed to examine cardiovascular risk factor changes from premenopause to postmenopause. Based on CAC scores collected on two follow-up visits (electron beam tomography [EBT] 1 and EBT4) scheduled 12 years apart, participants were classified into one of three groups: (1) no-detectable CAC group (n = 37; 0 CAC on both visits); (2) incident CAC group (n = 46; 0 CAC on the first visit and >0 CAC on the last visit); or (3) prevalent CAC group (n = 65; >0 CAC on both visits). PA data were collected regularly throughout the study using self-report questionnaires and accelerometers on EBT4.

RESULTS

The percentage of HWS participants with no detectable CAC decreased from 56.1% on EBT1 to 25.0% on EBT4. Times spent per day in accumulated moderate- to vigorous-intensity PA (MVPA) and bouts of MVPA were each significantly higher in the no-detectable CAC group when compared with the prevalent CAC group (both P ≤ 0.01). After covariate adjustment, these differences remained statistically significant (both P < 0.05). Although self-reported summary estimates collected throughout the study were significantly associated with accelerometer data on EBT4, there were no significant differences in self-reported PA levels by CAC group after covariate adjustment.

CONCLUSIONS

Study findings suggest that low levels of accelerometer-derived MVPA may be indicative of subclinical disease in older women.

Association of lipoprotein subfractions and coronary artery calcium in patient at intermediate cardiovascular risk

More precise estimation of the atherogenic lipid parameters could improve identification of residual risk beyond what is possible using traditional lipid risk factors. The aim of the present study was to explore the association between advanced analysis of lipoprotein subfractions and the prevalence of coronary artery calcium. Consecutive participants at intermediate cardiovascular risk who were undergoing computed tomographic assessment of coronary calcium (calcium score) were included. Using a validated ultracentrifugation method (the vertical autoprofile II test), cholesterol in eluting lipoprotein subfractions [i.e., low- (LDL), very-low-, intermediate-, and high-density lipoprotein subclasses, lipoprotein (a), and predominant LDL distribution] was directly quantified. A total of 410 patients were included (29% women, mean age 57 years), of whom 297 (72.4%) had coronary artery calcium. LDL pattern B (predominance of small dense particles) emerged as an independent predictor of coronary calcium after adjustment for traditional risk factors (odds ratio 4.46, 95% confidence interval 1.19 to 16.7). However, after additional stratification for dyslipidemia, as defined by conventional lipid profiling, a statistically significant prediction was only retained for high-density lipoprotein subfraction 2 (odds ratio 3.45, 95% confidence interval 2.03 to 50.1) and "real" LDL (odds ratio 6.10, 95% confidence interval 1.26 to 23.41) in the normolipidemia group and for lipoprotein (a) (odds ratio 7.81, 95% confidence interval 1.41 to 43.5) in the dyslipidemic group. In conclusion, advanced assessment of the lipoprotein subfractions [i.e., LDL pattern B, high-density lipoprotein subfraction 2, "real" LDL, and lipoprotein (a)] using the vertical autoprofile II test provided additional information to that of conventional risk factors on the prevalence of coronary artery calcium in patients at intermediate cardiovascular risk.

Physical activity and coronary artery calcification in two cohorts of women representing early and late postmenopause

OBJECTIVE

The aim of this study was to examine the association between physical activity (PA) and coronary artery calcification (CAC) among two cohorts of postmenopausal (PM) women representing early and late postmenopause.

METHODS

The cross-sectional relationship between PA and CAC was examined in 173 younger PM women (mean age ± SD, 56.8 ± 2.9 y) from the Women on the Move Through Activity and Nutrition (WOMAN) study and 121 older PM women (mean age ± SD, 73.9 ± 3.8 y) from the Walking Women Follow-up (WWF) study who had complete PA and CAC data. PA was measured objectively using a pedometer over a 7-day period in both cohorts. CAC was assessed using electron beam tomography. Descriptive statistics were used to describe median levels of PA and CAC, as well as proportions of detectable CAC (0 vs > 0).

RESULTS

Fifty-seven percent of WOMAN study participants and 74% of WWF study participants had detectable CAC. The median (interquartile range) CAC score was 1.4 (0-23.3) for participants in the WOMAN study and 38.8 (0-264.4) among WWF study participants. Median (interquartile range) step counts were 6,447 (4,823-8,722) steps per day in the WOMAN study and 5,466 (3,610-7,576) steps per day for WWF study participants. Among WWF study participants, there was a statistically significant inverse association between pedometer steps and CAC (P for trend = 0.002); no association was found among WOMAN study participants.

CONCLUSIONS

Among older PM women, higher levels of PA were associated with lower CAC. However, the relationship was not observed in PM women, likely due to the lower prevalence of CAC in this age group.

A polymorphism in the protease-like domain of apolipoprotein(a) is associated with severe coronary artery disease

OBJECTIVES

The purpose of this study was to identify genetic variants associated with severe coronary artery disease (CAD).

METHODS AND RESULTS

We used 3 case-control studies of white subjects whose severity of CAD was assessed by angiography. The first 2 studies were used to generate hypotheses that were then tested in the third study. We tested 12,077 putative functional single nucleotide polymorphisms (SNPs) in Study 1 (781 cases, 603 controls) and identified 302 SNPs nominally associated with severe CAD. Testing these 302 SNPs in Study 2 (471 cases, 298 controls), we found 5 (in LPA, CALM1, HAP1, AP3B1, and ABCG2) were nominally associated with severe CAD and had the same risk alleles in both studies. We then tested these 5 SNPs in Study 3 (554 cases, 373 controls). We found 1 SNP that was associated with severe CAD: LPA I4399M (rs3798220). LPA encodes apolipoprotein(a), a component of lipoprotein(a). I4399M is located in the protease-like domain of apolipoprotein(a). Compared with noncarriers, carriers of the 4399M risk allele (2.7% of controls) had an adjusted odds ratio for severe CAD of 3.14 (confidence interval 1.51 to 6.56), and had 5-fold higher median plasma lipoprotein(a) levels (P=0.003).

CONCLUSIONS

The LPA I4399M SNP is associated with severe CAD and plasma lipoprotein(a) levels.

Hormone therapy and coronary artery calcification in asymptomatic postmenopausal women: the Rancho Bernardo Study

OBJECTIVE

To determine (1) whether past or current hormone therapy (HT) in postmenopausal women is associated with subclinical coronary artery plaque burden, (2) whether any association is independent of age, body size, blood pressure, lipids, fasting plasma glucose, cigarette smoking, leisure time physical activity, alcohol intake, use of lipid-lowering medications, and socioeconomic status, and (3) whether any association varies by duration of HT or by the use of combined versus unopposed HT.

DESIGN

An observational study, with HT validated and coronary heart disease risk factors determined between 1997 and 1999 in a research clinic, and coronary artery calcium score (CACS) evaluated by electron beam computed tomography in 2001 through 2002. Participants were 204 community-dwelling postmenopausal women from the Rancho Bernardo cohort aged 55 to 78 years with no history of heart disease.

RESULTS

The odds of severe CACS in current estrogen users (n = 127) was 0.40 (95% CI 0.19, 0.82), controlling for all covariates. Past users (n = 40) had intermediate odds (multiply adjusted OR = 0.66, 95% CI = 0.28, 1.58). In subgroup analyses, age-adjusted associations did not differ between the 68 women using unopposed estrogen versus the 59 using an estrogen-progestin regimen. Women who had used HT for at least 10 years (n = 86) had significantly less (P = 0.01) plaque burden than shorter term users (n = 41).

CONCLUSIONS

Both the strong association and the duration of use effect independent of lifestyle and social class suggest an antiatherogenic effect of postmenopausal estrogen. Only a clinical trial can completely exclude confounding by social class, lifestyle, and unmeasured covariates.

Association of traditional and nontraditional cardiovascular risk factors with coronary artery calcification

Coronary artery calcification assessed by computed tomography is an emerging marker of coronary atherosclerosis. The authors examined the association of coronary calcium scores with traditional and nontraditional cardiovascular risk factors. In 1999-2000, they measured coronary artery calcium in 360 participants free of known coronary artery disease who had participated in 2 centers of the Atherosclerosis Risk in Communities (ARIC) Study. They related coronary calcium scores to risk factors measured in 1987-1989. Most traditional risk factors were associated with the coronary calcium score. For example, the multivariately adjusted odds ratio for an elevated score (> or = 100 versus < 100) was 3.5-fold greater per 10 years of age, 3.2-fold greater in men than in women, 3.1-fold greater with diabetes (statistically nonsignificant), and 1.4- to 1.7-fold greater per standard deviation greater increments of plasma cholesterol and pack-years of cigarettes smoked. Carotid artery intima-media thickness also was positively associated with coronary calcification. In contrast, a wide variety of hemostatic and inflammatory markers and serum chemistry values were unrelated to calcium scores. These findings reaffirmed the established role of traditional risk factors in the etiology of coronary artery disease, as assessed by computed tomography, but did not identify any important nontraditional risk factors.

Lack of association between lipoprotein(a) and coronary artery calcification in the Genetic Epidemiology Network of Arteriopathy (GENOA) study

OBJECTIVE

To investigate the relationship between lipoprotein(a) [Lp(a)] levels and the extent of coronary atherosclerosis in a cohort that consisted predominantly of hypertensive patients.

PATIENTS AND METHODS

Patients were ascertained through sibships that contained at least 2 individuals with essential hypertension diagnosed before the age of 60 years. The 10-year coronary heart disease (CHD) risk was estimated on the basis of the Framingham risk equation. Serum Lp(a) was measured by an immunoturbidimetric assay. Coronary artery calcification (CAC) was measured noninvasively by electron beam computed tomography and CAC score calculated using the Agatston score.

RESULTS

Patients included 765 non-Hispanic, white individuals (59% women) participating in the Genetic Epidemiology Network of Arteriopathy study. The mean +/- SD age of the patients was 62 +/- 8 years, and 77% had hypertension. The prevalence of detectable CAC was 87% in men and 60% in women. The CAC scores did not differ significantly across quintiles of Lp(a) levels in either men or women. In a multiple regression model that included conventional risk factors, Lp(a) levels were not related to CAC quantity in either sex. No significant interactions were noted between Lp(a) levels and the conventional risk factors in the prediction of CAC quantity. When stratified on the basis of the 10-year CHD risk, 26.5% of the patients were low risk (< 6%), 60.5% were intermediate risk (6%-20%), and 12.9% were high risk (> 20%). Lipoprotein(a) was not associated with CAC quantity within subgroups based on 10-year CHD risk.

CONCLUSION

In this cohort enriched with hypertensive patients, the estimated 10-year CHD risk did not appear to modify the lack of an association between Lp(a) levels and CAC.

Assessment of atherosclerotic risk factors and endothelial function in children and young adults with pediatric-onset systemic lupus erythematosus

OBJECTIVE

To characterize atherosclerotic risk factors and endothelial function in pediatric-onset systemic lupus erythematosus (SLE).

METHODS

Lipoproteins, oxidized state, and autoantibodies to oxidized low-density lipoprotein (Ox-LDL) were assessed. Endothelial function was evaluated using brachial artery reactivity.

RESULTS

Thirty-three SLE patients and 30 controls were studied. SLE subjects had significantly decreased mean high-density lipoprotein (HDL) cholesterol (41 mg/dl versus 51 mg/dl; P = 0.002) and apolipoprotein A-I (97 mg/dl versus 199 mg/dl; P = 0.0004). There was no difference between groups in markers of oxidized state (including nitric oxide metabolites, isoprostanes, and Ox-LDL) or in endothelial function. However, SLE subjects had increased median anti-Ox-LDL IgG (2,480 relative light units [RLU] versus 1,567 RLU; P = 0.0007) and IgG immune complexes with LDL (4,222 RLU versus 2,868 RLU; P = 0.002).

CONCLUSION

Pediatric SLE patients had significantly decreased levels of HDL cholesterol and apolipoprotein A-I and elevated titers of autoantibodies to Ox-LDL. Despite these atherosclerotic risk factors, SLE patients had normal measures of oxidized state and endothelial function.

Antioxidant vitamins C and E improve endothelial function in children with hyperlipidemia: Endothelial Assessment of Risk from Lipids in Youth (EARLY) Trial

BACKGROUND

Hyperlipidemia is associated with endothelial dysfunction, an early event in atherosclerosis and predictor of risk for future coronary artery disease. Epidemiological studies suggest that increased dietary intake of antioxidants reduces the risk of coronary artery disease. The purpose of this study was to determine whether antioxidant vitamin therapy improves endothelial function and affects surrogate biomarkers for oxidative stress and inflammation in hyperlipidemic children.

METHODS AND RESULTS

In a randomized, double-blind, placebo-controlled trial, the effects of antioxidant vitamins C (500 mg/d) and E (400 IU/d) for 6 weeks and the National Cholesterol Education Program Step II (NCEP-II) diet for 6 months on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery were examined in 15 children with familial hypercholesterolemia (FH) or the phenotype of familial combined hyperlipidemia (FCH). Antioxidant vitamin therapy improved FMD of the brachial artery compared with baseline (P<0.001) without an effect on biomarkers for oxidative stress (autoantibodies to epitopes of oxidized LDL, F2-isoprostanes, 8-hydroxy-2'-deoxyguanosine), inflammation (C-reactive protein), or levels of asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide.

CONCLUSIONS

Antioxidant therapy with vitamins C and E restores endothelial function in hyperlipidemic children. Early detection and treatment of endothelial dysfunction in high-risk children may retard the progression of atherosclerosis.

Impact of genetic defects on coronary atherosclerosis in patients suspected of having familial hypercholesterolaemia

BACKGROUND

In the present study we assessed whether the presence of genetic mutations typical of familial hypercholesterolaemia (FH) was associated with greater atherosclerosis in the coronary vessels in patients with severe hypercholesterolaemia and a family history of early cardiovascular disease.

MATERIALS AND METHODS

Two hundred and thirty-five patients selected for having severe hypercholesterolaemia and a family history of cardiovascular disease were classified as FH (57 men and 38 women) or non-FH (84 men and 56 women) according to a genetic analysis of the LDL-R or ApoB genes. Coronary atherosclerosis was evaluated by performing a thoracic CT scan and exercise stress testing.

RESULTS

Familial hypercholesterolaemia individuals had a significantly higher prevalence of coronary calcification than the non-FH patients from among both the men (OR = 3.90; 95% CI 1.86-8.19; P < 0.001) and the women (OR = 2.34; 95% CI 1.01-5.48; P = 0.05). In exercise stress testing, ECG abnormalities suggestive of cardiac ischaemia were found with a higher prevalence in the FH patients than the non-FH patients from among both the men (OR 6.15; 95% CI 2.16-17.5; P < 0.001) and the women (OR 4.76; 95% CI 0.91-24.6; P = 0.06). All differences were statistically significant after adjusting for age and cholesterol and for most classical risk factors that differed between the FH and non-FH groups.

CONCLUSION

Among patients with severe hypercholesterolaemia and a family history of early cardiovascular disease, the presence of a genetically ascertained FH is associated with a higher prevalence of coronary artery calcifications and a positive exercise stress test. These results suggest that despite a similar phenotype, patients carrying mutations suggestive of FH may have a greater cardiovascular risk than patients without these mutations.

Early statin therapy for acute coronary syndromes

OBJECTIVE

To review the clinical benefit of statins in the early management of acute coronary syndromes (ACSs) and their possible mechanisms of benefit.

DATA SOURCES

A MEDLINE search (1966-September 2001) was conducted using the following terms: pravastatin, lovastatin, simvastatin, atorvastatin, cerivastatin, fluvastatin, statins, hydroxymethylglutaryl coenzyme A reductase inhibitor, acute coronary syndromes, unstable angina, and myocardial infarction. Pertinent articles referenced in these publications were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

French- and English-language human and animal studies were selected and analyzed.

DATA SYNTHESIS

In addition to their lipid-lowering properties, statins produce several nonlipid-related properties. These pleiotropic properties include improved endothelial function, reduction of inflammation at the site of the atherosclerotic plaque, inhibition of platelet aggregation, and anticoagulant effects, all of which may result in clinical benefit during ACSs. Preliminary studies and retrospective analyses of large clinical trials support the hypothesis that statins may be of benefit in ACSs. A recently published randomized, double-blind, multicenter trial evaluated the clinical impact of high-dose atorvastatin in patients with ACSs. Use of atorvastatin resulted in a decrease in a combined endpoint of cardiovascular events. Furthermore, initiation of statin therapy during hospitalization improves long-term compliance and may significantly improve clinical outcome.

CONCLUSIONS

Early use of statins in ACSs appears to decrease cardiovascular events. We believe statin therapy should be initiated early (at the latest before hospital discharge) in all patients who have been hospitalized for ACSs. Ongoing studies will clarify the benefit of these agents in ACSs, the importance of their nonlipid-lowering properties, and the optimal cholesterol-target concentrations.

A review of electron beam computed tomography: implications for coronary artery disease screening

Coronary artery disease is the leading cause of death in the United States, thus the intense interest in a screening test that would allow early identification of coronary artery disease in its asymptomatic stage, allowing early aggressive targeted risk factor reduction. While office-based risk factor assessment is currently the reference standard for prediction of cardiac risk, several imaging tests are currently being investigated. Electron beam computed tomography (EBCT) can accurately identify calcium in the coronary tree noninvasively. Coronary calcium is clearly linked with coronary atherosclerosis. In population studies, populations with higher calcium scores have more calcium events. The predictive value of a calcium score for an individual is currently under investigation, as well as the incremental value of a calcium score over office-based risk assessment in cardiac risk prediction. This review looks at the current role of EBCT in the prevention of cardiovascular disease. It summarizes the current data for calcium as a screening tool, which is strongest in establishing that asymptomatic people undergo increased rates of revascularization after an EBCT test. Widespread clinical use of EBCT is not recommended, pending data to establish its efficacy in the role of risk factor reduction and prevention of cardiovascular disease.

Keeping an eye on cardiovascular risk. A practical, case-study approach to assessment in office practice

Primary care physicians typically encounter patients who are not at obvious risk for CAD but who nonetheless need and can benefit from lipid-lowering therapy. Applying algorithms or scoring systems can be helpful in estimating an individual patient's risk, but the basic tools available in everyday clinical practice can be used to alert physicians to elevated CAD risk in their patients. Those patients whose LDL-C level is at or above 220 mg/dL (5.69 mmol/L) should routinely and deservedly get clinical attention, but they account for only 2.5% to 5% of the population. Those with an "average" LDL-C level number in the millions, and from this patient pool come the coronary events that fill clinics and hospitals. Aggressive treatment approaches are required to meet NCEP objectives, and every indication suggests that these goals are just the minimum. The third report of the NCEP Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) has broadened the indications for drug therapy, reclarifying diabetes and peripheral vascular or cardiovascular disease equivalents and using a global evaluation concept, which will identify 30 million Americans in need of drug treatment. The statins safely and effectively lower LDL-C levels, which is the basis for instituting drug therapy, according to NCEP guidelines. Using these drugs also raises HDL-C levels, which is somewhat protective, and decreases triglyceride levels. The efficacy of statin therapy in both primary and secondary prevention of CAD is now well established. If used more often when dietary therapy fails, which happens quite often, and in doses sufficient to work effectively, statins have the power to turn the corner on the prevention and treatment of atherosclerotic coronary disease in the United States.

The case for early statin therapy in acute coronary syndromes

Three large secondary prevention studies have shown that, in patients with a history of cardiovascular disease, statin treatment reduces the risk of further events and lowers overall mortality. In these studies, total mortality was reduced by as much as 30% in high-risk groups and 22% in average-risk groups. However, these studies did not include patients immediately after the coronary event. There are many benefits to early intervention with statin therapy in patients with acute coronary syndromes, including reduction of the risk of a subsequent event, which is highest immediately after the index event. Early treatment may reduce this likelihood in the first months after a coronary event by stabilizing atherosclerotic plaques and improving endothelial function in addition to lowering low-density lipoprotein cholesterol levels. This article reviews the case for early statin therapy in patients with a history of coronary heart disease. Results of clinical studies have now shown early statin therapy to be safe and cost-effective in reducing in-hospital and 6-month mortality.

Recent advances in multifactorial regulation of vascular calcification

Calcification presents important clinical implications in cardiovascular diseases, especially in coronary arteries. Epidemiological evidence has shown the coexistence of vascular calcification with both atherosclerosis and osteoporosis, and increasing evidence has shown the role of hyperlipidemia and atherogenic phospholipids in vascular calcification. The etiology of vascular calcification is also increasingly recognized as an active process. Vascular calcification initiates with matrix vesicle formation and mineralization following a process similar to that in bone. In addition, many bone regulatory factors have been shown to be present in calcified atherosclerotic lesions. In this review, we focus on the new developments emerging during the past year in regulation of vascular calcification. Regulatory factors include matrix GLA protein, the phosphate cotransporter Pit-1, a calcium-sensing receptor related factor, osteoprotegerin, leptin, bisphosphonates and oxidized lipids. Some of these, including oxidized lipids, osteoprotegerin, and bisphosphonates, appear to regulate mineralization in both bone and vasculature and may account for the co-existence of osteoporosis and atherosclerotic calcification that is independent of age.

Arterial calcification: a review of mechanisms, animal models, and the prospects for therapy

The causes of arterial calcification are beginning to be elucidated. Macrophages, mast cells, and smooth muscle cells are the primary cells implicated in this process. The roles of a variety of bone-related proteins including bone morphogenetic protein-2 (BMP-2), matrix Gla protein (MGP), osteoprotegerin (OPG), osteopontin, and osteonectin in regulating arterial calcification are reviewed. Animals lacking MGP, OPG, smad6, carbonic anhydrase isoenzyme II, fibrillin-1, and klotho gene product develop varying extents of arterial calcification. Hyperlipidemia, vitamin D, nicotine, and warfarin, alone or in various combinations, produce arterial calcification in animal models. MGP has recently been discovered to be an inhibitor of bone morphogenetic protein-2, the principal osteogenic growth factor. Many of the forces that induce arterial calcification may act by disrupting the essential post-translational modification of MGP, allowing BMP-2 to induce mineralization. MGP requires gamma-carboxylation before it is functional, and this process uses vitamin K as an essential cofactor. Vitamin K deficiency, drugs that act as vitamin K antagonists, and oxidant stress are forces that could prevent the formation of GLA residues on MGP. The potential role of arterial apoptosis in calcification is discussed. Potential therapeutic options to limit the rate of arterial calcification are summarized.

Do conventional risk factors predict subclinical coronary artery disease? Results from the Prospective Army Coronary Calcium Project

BACKGROUND

Recent guidelines recommend against the routine use of coronary artery calcification (CAC) detection because the additive value over clinical prediction tools is uncertain. We compared CAC, with use of electron-beam computed tomography (EBCT), with clinical and serologic coronary risk factors for the identification of patients with increased coronary heart disease risk.

METHODS AND RESULTS

We studied 630 active-duty US Army personnel (39-45 years old) without known coronary artery disease (CAD) who were undergoing a routine physical examination as required by regulations. Each participant underwent clinical and serologic risk factor screening and EBCT. The cohort (mean age 42 +/- 2 years, 82% male) had a low predicted risk of coronary events (mean 5-year Framingham risk index [FRI] 1.6% +/- 1.2%). The prevalence of coronary calcification was 17.6% (male 20.6%, female 4.3%). Significant univariate correlates of CAC were total and low-density lipoprotein [LDL] cholesterol, triglycerides, systolic blood pressure, and body mass index. However, only LDL cholesterol was independently associated with CAC. There was a significant but weak relationship between CAC and the Framingham risk index (FRI) (receiver-operator characteristic [ROC] curve area 0.62 +/- 0.03, P <.001), which was not different from the relationship between CAC and LDL cholesterol alone (ROC curve area 0.61 +/- 0.03, P <.001). The prevalence of any CAC in men increased slightly across increasing quartiles of FRI: 17.0%, 20.8%, 33.0%, and 29.2% (P =.033). Other risk factors (family history, homocysteine, insulin, lipoprotein[a], and fibrinogen) were not related to CAC.

CONCLUSIONS

In this age-homogeneous, low-risk screening cohort, conventional coronary risk factors significantly underestimated the presence of premature, subclinical calcified coronary atherosclerosis. These data support the potential of CAC detection as an anatomic, plaque-burden diagnostic test to identify patients who may require more intensive risk-reduction therapies, independent of predicted clinical risk.