Lipoprotein(a) interactions with lipid and non-lipid risk factors in patients with early onset coronary artery disease: results from the NHLBI Family Heart Study

Modifiable and Non-Modifiable Risk Factors for Premature Coronary Heart Disease (PCHD): Systematic Review and Meta-Analysis

AIM

We aimed to compare the prevalence of modifiable and non-modifiable coronary heart disease (CHD) risk factors among those with premature CHD and healthy individuals.

METHODS

PubMed, CINAHL, Embase, and Web of Science databases were searched (review protocol is registered in PROSPERO CRD42020173216). The quality of studies was assessed using the National Heart, Lung and Blood Institute tool for cross-sectional, cohort and case-control studies. Meta-analyses were performed using Review Manager 5.3. Effect sizes for categorical and continuous variables, odds ratio (OR) and mean differences (MD)/standardised mean differences (SMD) with 95% confidence intervals (CI) were reported.

RESULTS

A total of n=208 primary studies were included in this review. Individuals presenting with premature CHD (PCHD, age ≤65 years) had higher mean body mass index (MD 0.54 kg/m2, 95% CI 0.24, 0.83), total cholesterol (SMD 0.27, 95% CI 0.17, 0.38), triglycerides (SMD 0.50, 95% CI 0.41, 0.60) and lower high-density lipoprotein cholesterol (SMD 0.79, 95% CI: -0.91, -0.68) compared with healthy individuals. Individuals presenting with PCHD were more likely to be smokers (OR 2.88, 95% CI 2.51, 3.31), consumed excessive alcohol (OR 1.40, 95% CI 1.05, 1.86), had higher mean lipoprotein (a) levels (SMD 0.41, 95% CI 0.28, 0.54), and had a positive family history of CHD (OR 3.65, 95% CI 2.87, 4.66) compared with healthy individuals. Also, they were more likely to be obese (OR 1.59, 95% CI 1.32, 1.91), and to have had dyslipidaemia (OR 2.74, 95% CI 2.18, 3.45), hypertension (OR 2.80, 95% CI 2.28, 3.45), and type 2 diabetes mellitus (OR 2.93, 95% CI 2.50, 3.45) compared with healthy individuals.

CONCLUSION

This meta-analysis confirms current knowledge of risk factors for PCHD, and identifying these early may reduce CHD in young adults.

Risk Factors for Premature Coronary Heart Disease in Women Compared to Men: Systematic Review and Meta-Analysis

Background: We aimed to systematically examine literature on the prevalence of known modifiable and nonmodifiable risk factors for premature coronary heart disease (PCHD) in women compared with men. Materials and Methods: PubMed, CINAHL, Embase, and Web of Science databases were searched. Review protocol is registered in PROSPERO (CRD42020173216). Quality was assessed using the National Heart, Lung, and Blood Institute tool. Review Manager 5.3 was used for meta-analysis. Effect sizes were expressed as odds ratio (OR) and mean differences/standardized mean differences (SMD) with 95% confidence intervals (CIs) for categorical and continuous variables. Results: In this PCHD cohort (age <65 years), the mean age of presentation in women was 3 years older than men. Women had higher total cholesterol (SMD 0.11; 95% CI 0.00 to 0.23) and higher high-density lipoprotein cholesterol (SMD 0.49; 95% CI 0.29 to 0.69). Women were more likely to have hypertension (OR 1.51, 95% CI 1.42 to 1.60), diabetes mellitus (OR 1.78, 95% CI 1.55 to 2.04), obesity (OR 1.33, 95% CI 1.24 to 1.42), metabolic syndrome (OR 3.73, 95% CI 1.60 to 8.69), stroke (OR 1.63, 95% CI 1.51 to 1.77), peripheral vascular disorder (OR 1.67, 95% CI 1.43 to 1.96), and depression (OR 2.29, 95% CI 1.96 to 2.67). Women were less likely to be smokers (OR 0.60, 95% CI 0.55 to 0.66), have reported alcohol intake (OR 0.36, 95% CI 0.33 to 0.40), and reported use of illicit drug (OR 0.32, 95% CI 0.16 to 0.62). Conclusions: Risk factor profile in PCHD has a clear sex difference that supports early, aggressive, holistic, but sex-specific, approach to prevention.

Lipoprotein(a) and coronary atheroma progression rates during long-term high-intensity statin therapy: Insights from SATURN

BACKGROUND & AIMS

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL)-like particle that associates with major adverse cardiovascular events (MACE). We examined relationships between Lp(a) measurements and changes in coronary atheroma volume following long-term maximally-intensive statin therapy in coronary artery disease patients.

METHODS

Study of coronary atheroma by intravascular ultrasound: Effect of Rosuvastatin Versus Atorvastatin (SATURN) used serial intravascular ultrasound measures of coronary atheroma volume in patients treated with rosuvastatin 40 mg or atorvastatin 80 mg for 24 months. Baseline and follow-up Lp(a) levels were measured in 915 of the 1039 SATURN participants, and were correlated with changes in percent atheroma volume (ΔPAV).

RESULTS

Mean age was 57.7 ± 8.6 years, 74% were men, 96% were Caucasian, with statin use prior to study enrolment occurring in 59.3% of participants. Baseline [median (IQR)] LDL-cholesterol (LDL-C) and measured Lp(a) levels (mg/dL) were 114 (99, 137) and 17.4 (7.6, 52.9) respectively; follow-up measures were 60 (47, 77), and 16.5 (6.7, 57.7) (change from baseline: p < 0.001, p = 0.31 respectively). At baseline, there were 676 patients with Lp(a) levels <50 mg/dL [median Lp(a) of 10.9 mg/dL], and 239 patients with Lp(a) levels ≥ 50 mg/dL [median Lp(a) of 83.2 mg/dL]. Quartiles of baseline and follow-up Lp(a) did not associate with ΔPAV. Irrespective of the achieved LDL-C (<vs. ≥70 mg/dL), neither baseline nor on-treatment (<vs. ≥median) Lp(a) levels significantly associated with ΔPAV. No significant differences were observed in ΔPAV in Lp(a) risers versus non-risers, nor in those patients with baseline or on-treatment Lp(a) levels <vs. > 50 mg/dL.

CONCLUSIONS

In coronary artery disease patients prescribed long-term maximally intensive statin therapy with low on-treatment LDL-C levels, measured Lp(a) levels (predominantly below the 50 mg/dL threshold) do not associate with coronary atheroma progression. Alternative biomarkers may thus associate with residual cardiovascular risk in such patients.

Lipoprotein(a) Interactions With Low-Density Lipoprotein Cholesterol and Other Cardiovascular Risk Factors in Premature Acute Coronary Syndrome (ACS)

Background

Current recommendations for lipoprotein(a) (Lp[a]) focus on the control of other risk factors, including lowering low‐density lipoprotein cholesterol (LDL‐C), with little evidence to support this approach. Identifying interactions between Lp(a) and other risk factors could identify individuals at increased risk for Lp(a)‐mediated disease.

Methods and Results

We used a case‐only study design and included 939 participants (median age=49 years, interquartile range 46–53, women=33.1%) from the GENdEr and Sex determInantS of cardiovascular disease: from bench to beyond‐Premature Acute Coronary Syndrome (GENESIS‐PRAXY) study, a multicenter prospective cohort study of premature acute coronary syndrome. There was a higher prevalence of elevated Lp(a) levels (>50 mg/dL; 80th percentile) in PRAXY participants as compared to the general population (31% versus 20%; P<0.001). Lp(a) was strongly associated with LDL‐C (adjusted β 0.17; P<0.001). Individuals with high Lp(a) were more likely to have LDL‐C >2.5 mmol/L, indicating a synergistic interaction (adjusted odds ratio 1.51; 95% CI 1.08–2.09; P=0.015). The interaction with high Lp(a) was stronger at increasing LDL‐C levels (LDL‐C >3.5, adjusted odds ratio 1.87; LDL‐C >4.5, adjusted odds ratio 2.72). In a polytomous logistic model comparing mutually exclusive LDL‐C categories, the interaction with high Lp(a) became attenuated at LDL‐C ≤3.5 mmol/L (odds ratio 1.16; 95% CI 0.80–1.68, P=0.447). Other risk factors were not associated with high Lp(a).

Conclusions

In young acute coronary syndrome patients, high Lp(a) is more prevalent than in the general population and is strongly associated with high LDL‐C, suggesting that Lp(a) confers greater risk for acute coronary syndrome when LDL‐C is elevated. Individuals with high Lp(a) and LDL‐C >3.5 mmol/L may warrant aggressive LDL‐C lowering.

Vitamin D and cardiometabolic health: a review of the evidence

The cardiometabolic syndrome (MetS) is a clustering of related metabolic abnormalities including abdominal adiposity, insulin resistance, hypertension, dyslipidaemia and increased inflammatory and thrombotic markers, which is linked to increased risk of type 2 diabetes, CVD and overall mortality. Several cross-sectional and prospective studies have shown an association between low vitamin D status, as indicated by concentrations of serum 25-hydroxyvitamin D (s25(OH)D), and increased prevalence of the MetS and individual CVD risk factors. These epidemiological observations are supported by mechanistic studies but experimental data are limited. The available data from intervention studies are largely confounded as most vitamin D supplementation trials were mainly carried out to explore the role of Ca in CVD and include Ca in the treatment arms. Inadequate consideration of seasonal effects on s25(OH)D concentrations is also a common design flaw in most studies. Further complications arise from shared risk factors such as adiposity and ageing, which predispose individuals to exhibit both a more pronounced risk profile and relatively lower s25(OH)D concentrations. In conclusion, while epidemiological associations are promising and a rationale for low vitamin D status as a potentially modifiable risk factor for CVD is supported by mechanistic data, suitable experimental data from appropriately designed trials are just beginning to emerge. As yet, this body of literature is too immature to draw firm conclusions on the role of vitamin D in CVD prevention. Carefully controlled vitamin D trials in well-described population groups using intervention doses that are titrated against target s25(OH)D concentrations could yield potentially valuable outcomes that may have a positive impact on CVD risk modification.

Asymmetric dimethylarginine potentiates lung inflammation in a mouse model of allergic asthma

Nitric oxide (NO), formed by nitric oxide synthase (NOS), is an important mediator of lung inflammation in allergic asthma. Asymmetric dimethylarginine (ADMA), a competitive endogenous inhibitor of NOS, is metabolized by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). Elevated ADMA has been shown to affect lung function in mice, and by inhibiting NOS it alters NO and reactive oxygen species production in mouse lung epithelial cells. However, the effects of altered ADMA levels during lung inflammation have not been explored. A model of allergen-induced airway inflammation was utilized in combination with the modulation of endogenous circulating ADMA levels in mice. Airway inflammation was assessed by quantifying inflammatory cell infiltrates in lung lavage and by histology. Lung DDAH expression was assessed by quantitative PCR and immunohistochemistry. Nitrite levels were determined in lung lavage fluid as a measure of NO production. iNOS expression was determined by immunohistochemistry, immunofluorescence, Western blot, and quantitative PCR. NF-κB binding activity was assessed by a transcription factor binding assay. Allergen-induced lung inflammation was potentiated in mice with elevated circulating ADMA and was reduced in mice overexpressing DDAH. Elevated ADMA reduced nitrite levels in lung lavage fluid in both allergen-challenged and control animals. ADMA increased iNOS expression in airway epithelial cells in vivo following allergen challenge and in vitro in stimulated mouse lung epithelial cells. ADMA also increased NF-κB binding activity in airway epithelial cells in vitro. These data support that ADMA may play a role in inflammatory airway diseases such as asthma through modulation of iNOS expression in lung epithelial cells.

Interactions of lipoprotein(a) with diabetes mellitus, apolipoprotein B and cholesterol enhance the prognostic values for coronary artery disease

BACKGROUND

Synergistic interactions between elevated serum lipoprotein(a) [Lp(a)] and other unfavorable risk factors have been proposed to cause very high risk for coronary artery disease (CAD). The aim of this study was to examine the potential interactions between Lp(a) and other risk factors.

METHODS

The profiles of serum (apo)(lipo)proteins, markers of inflammation, indicators of hemoconcentration as well as classical risk factors were determined in 264 clinically stable angiographically documented subjects. Correlation, linear and logistic regression and stratification analyses were performed.

RESULTS

The frequency and severity of CAD and the prevalence of diabetes mellitus were significantly higher in the 3rd relative to 1st tertile of Lp(a). Subjects with Lp(a) levels in the upper tertile had significantly higher levels of serum glucose, total cholesterol and low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (apoB), calcium, phosphate and their ion product. Bivariate correlation analysis indicated that serum Lp(a) was associated positively with the occurrence and severity of CAD, diabetes mellitus and the levels of serum glucose, cholesterol, LDL-C, apoB, calcium, phosphate and inversely to physical inactivity. In linear regression analysis, LDL-C (or apoB), diabetes, physical inactivity and phosphate were the major independent determinants of Lp(a) values. In multiple logistic regression analysis, after adjusting for major risk factors, Lp(a) showed a significant and independent association with the prevalence of CAD. By constructing dummy combined variables, elevated Lp(a) accompanied with diabetes or high levels of serum glucose, apoB and cholesterol exhibited an amplified high risk for CAD.

CONCLUSIONS

The results indicate that serum Lp(a) does interact multiplicatively with diabetes, apoB and cholesterol. The simultaneous assessment of Lp(a) and interactive risk factors enhances the discriminating value for CAD.

How to identify patients with vulnerable plaques

Multiple strategies are available for clinicians to identify patients at high risk for cardiovascular events. Two commonly discussed strategies are the identification of vulnerable plaques and the identification of vulnerable patients. The strategy of identifying vulnerable patients is less invasive, easy to implement and not restricted primarily to one vascular bed (e.g. coronary or cerebral). This review discusses the utility as well as the limitations of global risk assessment tools to identify such patients. The utility of biomarkers [C-reactive protein, lipoprotein-associated phospholipase A(2) and lipoprotein(a)] and non-invasive measures of atherosclerosis burden (coronary artery calcium scores, carotid intima-media thickness and ankle-brachial index) in identifying patients at high risk for cardiovascular events are also discussed.

Canadian Cardiovascular Society position statement--recommendations for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease

Since the last publication of the recommendations for the management and treatment of dyslipidemia, new clinical trial data have emerged that support a more vigorous approach to lipid lowering in specific patient groups. The decision was made to update the lipid guidelines in collaboration with the Canadian Cardiovascular Society. A systematic electronic search of medical literature for original research consisting of blinded, randomized controlled trials was performed. Meta-analyses of studies of the efficacy and safety of lipid-lowering therapies, and of the predictive value of established and emerging risk factors were also reviewed. All recommendations are evidence-based, and have been reviewed in detail by primary and secondary review panels. Major changes include a lower low-density lipoprotein cholesterol (LDL-C) treatment target (lower than 2.0 mmol/L) for high-risk patients, a slightly higher intervention point for the initiation of drug therapy in most low-risk individuals (LDL-C of 5.0 mmol/L or a total cholesterol to high-density lipoprotein cholesterol ratio of 6.0) and recommendations regarding additional investigations of potential use in the further evaluation of coronary artery disease risk in subjects in the moderate-risk category.

Cross-talk between constitutive and inducible NO synthase: an update

Inducible nitric oxide synthase (iNOS) is expressed upon exposure of some cell types to bacterial lipopolysaccharides (LPS) and/or a variety of proinflammatory cytokines. The authors present an overview of some of the recent findings further supporting the notion that this response takes place after an early decline in constitutive nitric oxide (NO) levels (i.e., NO released by constitutive NOS, cNOS). This response is indeed critical for allowing activation of the transcription factor NF-kappaB. Thus, generation of NO by cNOS represents a limiting factor for iNOS expression. Some of the physiological and pathological implications of the cross-talk between these two NOS isoforms are discussed. In addition, the results of recent studies are summarized, suggesting possible mechanisms whereby LPS and/or proinflammatory cytokines may cause inhibition of cNOS.

Quo vadis haemapheresis. Current developments in haemapheresis

The techniques of haemapheresis originated in the development of centrifugal devices separating cells from plasma and later on plasma from cells. Subsequently membrane filtration was developed allowing for plasma-cell separation. The unspecificity of therapeutic plasma exchange led to the development of secondary plasma separation technologies being specific, semi-selective or selective such as adsorption, filtration or precipitation. In contrast on-line differential separation of cells is still under development. Whereas erythrocytapheresis, granulocytapheresis, lymphocytapheresis and stem cell apheresis are technically advanced, monocytapheresis may need further improvement. Also, indications such as erythrocytapheresis for the treatment of polycythaemia vera or photopheresis though being clinically effective and of considerable importance for an appropriate disease control are to some extent under debate as being either too costly or without sufficient understanding of the mechanism. Other forms of cell therapy are under development. Rheohaemapheresis as the most advanced technology of extracorporeal haemorheotherapy is a rapidly developing approach contributing to the treatment of microcirculatory diseases and tissue repair. Whereas the control of a considerable number of (auto-) antibody mediated diseases is beyond discussion, the indication of apheresis therapy for immune complex mediated diseases is quite often still under debate. Detoxification for artificial liver support advanced considerably during the last years, whereas conclusions on the efficacy of septicaemia treatment are debatable indeed. LDL-apheresis initiated in 1981 as immune apheresis is well established since 24 years, other semi-selective or unspecific procedures, allowing for the elimination of LDL-cholesterol among other plasma components are also being used. Correspondingly Lp(a) apheresis is available as a specific, highly efficient elimination procedure superior to techniques which also eliminate Lp(a). Quality control systems, more economical technologies as for instance by increasing automation, influencing the over-interpretation of evidence based medicine especially in patients with rare diseases without treatment alternative, more insight into the need of controlled clinical trials or alternatively improved diagnostic procedures are among others tools ways to expand the application of haemapheresis so far applied in cardiology, dermatology, haematology, immunology, nephrology, neurology, ophthalmology, otology, paediatrics, rheumatology, surgery and transfusion medicine.

Lipoprotein (a) and coronary heart disease among women: beyond a cholesterol carrier?

AIMS

With its homology with plasminogen, lipoprotein(a) [Lp(a)] may be related to thrombosis and inflammation. We assessed the role of Lp(a) in coronary heart diseases (CHD) by a recently developed assay that is not affected by the plasminogen-like Kringle-type-2 repeats.

METHODS AND RESULTS

Of 32 826 women from the Nurses' Health Study, who provided blood at baseline, we documented 228 CHD events during 8 years of follow-up. Each case was compared with two matched controls. In a multivariable model adjusted for body mass index, family history, hypertension, diabetes, post-menopausal hormone use, physical activity, blood drawing characteristics, and alcohol intake, the odd ratio (OR) for Lp(a) levels > or =30 mg/dL was 1.9(95% CI: 1.3-3.0) when compared with those with Lp(a)<30 mg/dL. Women with high levels of both Lp(a) (> or =30 mg/dL) and fibrinogen (> or =400 mg/dL) had an OR of 3.2(95% CI: 1.6-6.5) for CHD, when compared with the combination of low levels (P interaction=0.05). Women with high levels of both Lp(a) and C-reactive protein (> or =3 mg/L) had an OR of 3.67(95% CI: 2.03-6.64) for CHD, when compared with the combination of low levels (P interaction=0.06).

CONCLUSION

Lp(a) levels >30 mg/dL are associated with twice the risk of CHD events among women and may be related to thrombosis and inflammation.

The susceptibility of lipoprotein(a) to copper oxidation is correlated with the susceptibility of autologous low density lipoprotein to oxidation

OBJECTIVES

Lipoprotein(a) [Lp(a)] can be oxidized by copper in vitro in a way comparable to low-density lipoprotein (LDL). We sought to determine whether the susceptibility of Lp(a) to oxidation is correlated with the susceptibility of autologous heterogeneous LDL, with apolipoprotein(a) [apo(a)] molecular size, or with both factors.

DESIGN AND METHODS

We examined shifts in electrophoretic mobility of Lp(a) and LDL caused by copper oxidation in plasma samples from 81 healthy men. The effect of copper oxidation on different-sized apo(a) was also evaluated.

RESULTS

There was a close correlation between the relative electrophoretic mobilities of oxidized Lp(a) and oxidized LDL in subjects, especially with small-sized apo(a) (n = 25, r = 0.72, p < 0.0001). Oxidative processes in Lp(a) resulted in the degradation of large-, but not small-sized apo(a).

CONCLUSIONS

The susceptibility of Lp(a) to oxidation is correlated with that of autologous LDL. Large-sized apo(a) may be involved in the Lp(a) oxidation.

Relation of lipoprotein(a) as coronary risk factor to type 2 diabetes mellitus and low-density lipoprotein cholesterol in patients > or =65 years of age (The Italian Longitudinal Study on Aging)

High levels of serum lipoprotein(a) [Lp(a)] have been associated with increased risk of coronary artery disease (CAD), but this association apparently is not confirmed in elderly people. We evaluated the interactions of Lp(a) with lipid and nonlipid CAD risk factors in a sample of subjects enrolled in the prevalence survey (1992 to 1993) of the Italian Longitudinal Study on Aging (ILSA). The entire population consisted of 5,632 elderly people, aged 65 to 84 years, randomly selected in 8 Italian municipalities. The present cross-sectional study included 400 free-living elderly subjects (74 +/- 6 years) from the randomized cohort of Casamassima (Bari, Southern Italy) (n = 704). The results showed that in the elderly population, high serum Lp(a) is a CAD risk factor dependent on type 2 diabetes mellitus and elevated low-density lipoprotein (LDL) cholesterol levels. In particular, the combined effect of high Lp(a) (> or =20 mg/dl) and high LDL cholesterol (> or =3.63 mmol/L [> or =140 mg/dl]), increases coronary risk by 2.75 (95% confidence interval 7.70 to 0.99); finally, the effect of Lp(a) > or =20 mg/dl and LDL cholesterol > or =3.63 mmol/L (> or =140 mg/dl), combined with type 2 diabetes mellitus, increases risk of CAD by 6.65 (95% confidence interval 35.40 to 1.25). In the elderly, elevated Lp(a) levels appear not to be an independent predictor of CAD, but this lipoprotein is a risk factor only in subjects with type 2 diabetes mellitus and elevated LDL cholesterol.

Lipoprotein(a) further increases the risk of coronary events in men with high global cardiovascular risk

OBJECTIVES

This prospective population study was conducted to assess the role of elevated lipoprotein(a) [Lp(a)] as a coronary risk factor.

BACKGROUND

The role of elevated Lp(a) as a risk factor for coronary heart disease is controversial. In addition, little attention has been paid to the interaction of Lp(a) with other risk factors.

METHODS

A total of 788 male participants of the Prospective Cardiovascular Münster (PROCAM) study aged 35 to 65 years were followed for 10 years. Both Lp(a) and traditional cardiovascular risk factors (e.g., age, low density lipoprotein [LDL] cholesterol, high density lipoprotein [HDL] cholesterol, triglycerides, systolic blood pressure, cigarette smoking, diabetes mellitus, angina pectoris, and family history of myocardial infarction) were evaluated in 44 men who suffered from myocardial infarction, and in 744 men who survived without major coronary events or stroke. A multiple logistic function algorithm was used to estimate global cardiovascular risk by the combined effects of traditional risk factors.

RESULTS

Overall, the risk of a coronary event in men with an Lp(a) > or =0.2 g/liter was 2.7 times that of men with lower levels (95% confidence interval [CI]: 1.4 to 5.2). This increase in risk was most prominent in men with LDL cholesterol level > or =4.1 mmol/liter (relative risk [RR]: 2.6; 95% CI: 1.2 to 5.7), with HDL cholesterol < or =0.9 mmol/liter (RR 8.3; 95% CI: 2.0 to 35.5), with hypertension (RR 3.2; 95% CI: 1.4 to 7.2), or within the two highest global risk quintiles (relative risk: 2.7; 95% CI: 1.3 to 5.7).

CONCLUSIONS

Lp(a) increases the coronary risk, especially in men with high LDL cholesterol, low HDL cholesterol, hypertension and/or high global cardiovascular risk.

Lipoprotein (a) as a predictor of myocardial infarction in middle-aged men

PURPOSE

Whether serum lipoprotein (a) [Lp(a)] levels are an independent risk factor for coronary heart disease has been controversial. We have investigated its status in a prospective population survey, the Second Northwick Park Heart Study.

METHODS

We recruited 2,616 men 50 to 61 years old from nine primary care practices in the United Kingdom. Baseline serum Lp(a) levels were measured by enzyme-linked immunosorbent assay (ELISA) and were analyzed in 3 groups (<25th percentile, 25th to 75th percentile, and >75th percentile) to overcome the problem of some measurements falling below the threshold of the assay. Coronary end points included sudden cardiac death, acute myocardial infarction, silent myocardial infarction on the electrocardiogram, and coronary artery bypass surgery.

RESULTS

During a mean of 6 years of follow-up, 121 men had coronary events. In a multivariate analysis that also adjusted for fibrinogen, Apo-A1, Apo-B, and triglyceride levels, we identified several independent risk factors for coronary events, including cholesterol level (hazard ratio [HR] = 1.5 per SD 95% confidence interval [CI] 1.3 to 1.8), diabetes (HR = 4.1, 95% CI: 2. 0 to 8.4), current versus never smoking (HR = 2.5, 95% CI: 1.5 to 4.1), diastolic blood pressure (HR = 1.4 per SD, 95% CI: 1.1 to 1.7), Apo-A1 (HR = 0.8 per SD, 95% CI: 0.6 to 0.9), age (HR = 1.3 per SD, 95% CI: 1.1 to 1.6), and Lp(a) (>26.3 mg/dL [75th percentile] versus <2.9 mg/dL [25th percentile], HR = 1.9, 95% CI: 1.1 to 3.3]. There was a statistically significant (P = 0.01) difference in risk between the three levels of Lp(a).

CONCLUSIONS

We found that a high Lp(a) level was an independent predictor of the development of coronary heart disease in middle-aged men.

Associations between classical cardiovascular risk factors and coronary artery disease in two countries at contrasting risk for myocardial infarction: the PRIME study

PURPOSE

In two countries with contrasting risk for coronary artery disease (CAD)-Northern Ireland and France-a case-control study was performed on baseline data within a cohort study to compare the strength of the associations between CAD prevalence and classical risk factors.

METHOD AND RESULTS

A sample of 9561 men, aged 50-60 years, was studied: 382 had had myocardial infarction or angina, and 9179 were controls. In both countries, variables associated with CAD were age, body mass index, hypertension, diabetes, family history of myocardial infarction (MI), tobacco consumption, triglycerides, HDL-cholesterol, apolipoprotein A-I and B levels. Logistic regression analyses were conducted using standardized odds ratios. The strength of the associations with CAD was rather similar in the two countries (Northern Ireland versus France) for age [1.26 (1.10-1. 45) vs. 1.41 (1.17-1.69)], family history of MI [1.50 (1.04-2.15) vs. 1.83 (0.99-3.37)], hypertension [1.49 (1.13-1.97) vs. 1.67 (1.14-2. 44)], diabetes [5.42 (2.53-11.60) vs. 2.24 (1.06-4.73)], tobacco consumption [1.43 (1.27-1.60) vs. 1.39 (1.22-1.58)], HDL-cholesterol [0.80 (0.68-0.94) vs. 0.86 (0.70-1.06)] and triglyceride levels [1. 17 (1.01-1.36) vs. 1.10 (0.91-1.32)]. Discrepancies concerned lipoprotein(a) [1.22 (1.06-1.40) vs. 0.96 (0.81-1.15), P<0.01], with stronger associations in Northern Ireland than in France.

CONCLUSION

It is concluded that the higher prevalence of CAD in Northern Ireland cannot be explained by major differences in the susceptibility to classical risk factors; the difference in risk of CAD appears mainly related in Northern Ireland to other risk factors including a worse lipid profile and genetic/environmental interactions.

Lp(a) and conventional risk profiles predict the severity of coronary stenosis in high-risk hospital-based patients

AIMS

To explore predictive power of Lp(a), of conventional lipoprotein profiles and their carrier proteins, and of biometric measurements, for the presence and severity of angiographically documented coronary disease in high-risk patients, and to compare risk profiles in men and women.

METHODS

We determined coronary artery disease (CAD) risk factors in 1308 Australian Caucasian patients (313 women and 995 men) aged < or =65 years who consecutively underwent coronary angiography.

RESULTS

In univariate analyses of the risk factors, lipid profiles, Lp(a), cigarette smoking, diabetes, hypertension and obesity were all higher in men and women with CAD and changed significantly with the number of significantly diseased vessels (> or =50% luminal obstruction). When stepwise logistic regression analysis was applied, age (OR 1.06, 95% CI: 1.04-1.09), TC/HDL-C (OR 1.29, 95% CI: 1.15-1.45), male gender (OR 2.64, 95% CI: 1.67-4.16), hyperLp(a) (> or =300 mg/L) (OR 2.09, 95% CI: 1.42-3.07), lifetime smoking dose (OR 1.02, 95% CI: 1.01-1.03), diabetes (OR 2.19, 95% CI: 1.14-4.18) and waist/hip ratio (OR 14.53, 95% CI: 1.21-174.90) were predictive of the disease. Both Lp(a) levels and percentage of hyperLp(a) increased linearly with the number of significantly diseased vessels. When the analyses were conducted in men and women separately, hyperLp(a), TC/HDL-C, lifetime smoking dose and age remained as significant predictors in both groups but the waist/hip ratio was only predictive in women.

CONCLUSIONS

As Lp(a) is an independent predictor of the occurrence and extent of coronary stenosis and relevant to treatment options, we suggest that it should be measured routinely in the coronary risk profile assessment of high-risk patients.

Comparison of laboratory parameters as risk factors for the presence and the extent of coronary or carotid atherosclerosis: the significance of apolipoprotein B to apolipoprotein all ratio

We compared several "new" risk factors (autoantibodies to oxidatively modified low density lipoprotein (LDL), sialic acid content of LDL, bilirubin and C-reactive protein) with "conventional" risk factors (apolipoprotein (apo) AI, AII and B, lipoprotein(a), triglycerides, and total, LDL and high density lipoprotein (HDL) cholesterol) for the presence and the extent of coronary or carotid atherosclerosis. Forty male patients with angiographically proven coronary atherosclerosis and 31 male patients with ultrasound-proven extracranial carotid atherosclerosis were compared to 40 age matched (53+/-5 years) healthy males as control subjects, with negative parental history of atherosclerosis, no clinical signs of systemic or organ-related ischemic disease and normal extracranial carotid arteries. The apo B/apo All ratio most powerfully indicated the presence and the extent of coronary or carotid atherosclerosis. Elevated lipoprotein(a) contributed significant additional information in the assessment of the atherosclerotic risk. Increase in C-reactive protein indicated the presence (but not the extent) of coronary or carotid atherosclerosis with a similar power as lipoprotein(a). Decreased values of total bilirubin indicated the presence of atherosclerosis only in smokers. Autoantibodies to oxidatively modified LDL additionally described the atherosclerotic process, but were less important than apolipoproteins, lipoprotein(a), C-reactive protein or bilirubin. Sialic acid content of LDL added no information to the parameters discussed above. We demonstrated that in male patients apolipoproteins, especially the apo B/apo All ratio, were better indicators of the presence and the extent of coronary or carotid atherosclerosis than C-reactive protein, bilirubin, autoantibodies to oxidatively modified LDL or sialic acid content of LDL.

Epidemiology and prevention of coronary heart disease in families

Although family histories are used primarily to aid in diagnosis and risk assessment, their value is enhanced when the family is considered as a unit for research and disease prevention. The value of a family history of coronary heart disease (CHD) is increased when the age, sex, number of relatives, and age at onset of disease are incorporated in a quantitative family risk score. Medical and lifestyle risk factors that aggregate in families include dyslipidemia, hypertension, obesity, hyperfibrinogenemia, diabetes mellitus, smoking habits, eating patterns, alcohol consumption, physical activity, and socioeconomic status. Advances in detecting and understanding interactions between genetic susceptibility and modifiable risk factors should lead to improvements in prevention and treatment. However, working with families can be difficult. In the United States, families are usually small, are often widely dispersed, and may not be intact. Family histories may be unknown, affected relatives may be dead, and secular trends mask similarities among generations. Many exposures occur outside the home, and families change over time. Ethical, legal, and social issues arise when dealing with families. Nevertheless, opportunities are missed when research, clinical practice, and prevention focus on individual patients. Greater emphasis on families is needed to reduce the burden of CHD.

Oxidized low density lipoprotein is a prognostic marker of transplant-associated coronary artery disease

Retrospective studies identified oxidized low density lipoprotein (LDL) in the blood as a diagnostic marker of coronary artery disease (CAD). This prospective study sought to determine the prognostic value of oxidized LDL for CAD in cardiac transplant patients. Oxidized LDL was measured in 99 cardiac transplant patients with normal coronary angiograms at baseline and was measured again after a median follow-up of 2 years at the time of a second angiogram. Twenty-one patients developed angiographically detectable cardiac transplant vasculopathy (cases), and 78 individuals did not (controls). Cases had significantly higher baseline plasma levels of oxidized LDL than did controls: 1.18+/-0.70 versus 0.57+/-0.20 mg/dL (mean+/-SD, P<0.0001). The increase of oxidized LDL at the end of the follow-up was significantly higher in cases than in controls: 0. 75+/-0.73 mg/dL versus 0.14+/-0.27 mg/dL (P<0.0001). Baseline levels of oxidized LDL predicted cardiac transplant vasculopathy (chi(2)=16, P<0.0001) independent of pretransplant ischemic cardiomyopathy, time after transplantation, age, and serum levels of LDL and high density lipoprotein cholesterol. The development of transplant CAD was associated with a further increase of plasma levels of oxidized LDL (chi(2)=14, P=0.0002). Oxidized LDL is a prognostic marker of transplant CAD.

Contribution of fasting hyperinsulinemia to prediction of atherosclerotic cardiovascular disease status in 293 hyperlipidemic patients

In a cross-sectional study of 293 nondiabetic patients (169 men and 124 women) referred for the diagnosis and treatment of hyperlipidemia, our specific aim was to determine whether fasting serum insulin independently contributes to the prediction of atherosclerotic cardiovascular disease (ASCVD) status. Of the 169 men and 124 women, 65 (38%) and 44 (35%), respectively, had ASCVD with at least one of the following: unstable angina, myocardial infarction (MI), angioplasty, coronary artery bypass graft (CABG), claudication, transient ischemic attack, or ischemic stroke. In addition, 42% and 38% had fasting hyperinsulinemia (> or =20 microU/mL). Fasting serum insulin of 20 microU/mL or higher was very common in women (59% to 100%) and men (67% to 88%) when hypertension, obesity, top-decile triglyceride (TG), and bottom-decile high-density lipoprotein cholesterol (HDLC) were concurrent in various combinations. ASCVD events (present or absent) were dependent variables in a stepwise logistic regression model with explanatory variables including age, gender, race, hypertension, cigarette smoking, ASCVD in first-degree relatives at age 55 years or less, Quetelet Index, fasting serum insulin, a gender x insulin interaction term, anticardiolipin antibodies (ACLAs) IgG and IgM, total cholesterol to HDLC ratio, TG, lipoprotein(a) [Lp(a)], and homocysteine. The risk odds ratio for ASCVD (109 events and 184 nonevents) for subjects with top-decile insulin (vthe bottom nine deciles) was 3.71, with a 95% confidence interval (CI) of 1.62 to 8.9 (P = .002). For patients with MI and/or CABG and/or angioplasty ([MCA] 63 events and 184 nonevents), the risk odds ratio for top-decile insulin versus the rest was 5.07 (95% CI, 1.83 to 14.8, P = .002). For patients with MCA at age 55 or less, the gender x insulin interaction term was significant (P = .0004); the risk odds ratio for men with top-decile insulin was 13.28 (95% CI, 3.82 to 51.65, P = .0001). Hyperinsulinemia is very common in nondiabetic hyperlipidemic women and men. Fasting serum insulin, a crude, simple, practical, and inexpensive measure, independently and uniformly improved the prediction of ASCVD status beyond traditional risk factors and lipid variables in patients referred for treatment of hyperlipidemia.

Lipoprotein(a): intrigues and insights

Lipoprotein(a) is an atherogenic, cholesterol ester-rich lipoprotein of unknown physiological function. The unusual species distribution of lipoprotein(a) and the extreme polymorphic nature of its distinguishing apolipoprotein component, apolipoprotein(a), have provided unique challenges for the investigation of its biochemistry, genetics, metabolism and atherogenicity. Some fundamental questions regarding this enigmatic lipoprotein have escaped elucidation, as will be highlighted in this review.