Thrombogenic factors and recurrent coronary events

Tesaglitazar, a dual peroxisome proliferator-activated receptor alpha/gamma agonist, improves apolipoprotein levels in non-diabetic subjects with insulin resistance

AIM

To determine the effects of the peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist tesaglitazar on serum levels of apolipoprotein (apo) A-I, apoB, and apoCIII in non-diabetic insulin-resistant subjects.

METHODS

This randomized, double-blind, multicentre, placebo-controlled trial examined the effect of tesaglitazar (0.1, 0.25, 0.5, and 1mg) once daily for 12 weeks on apolipoprotein levels in 390 abdominally obese subjects with hypertriglyceridaemia.

RESULTS

Tesaglitazar dose-dependently increased serum concentrations of apoA-I (p<0.009) and decreased concentrations of apoB (p<0.0001), the apoB/apoA-I ratio (p<0.0001), and apoCIII (p<0.0001). Similar improvements were observed in all subgroups of subjects, where individuals were grouped according to age, gender, baseline body mass index, serum triglycerides and high-density lipoprotein cholesterol levels. Low-density lipoprotein particle concentrations were also dose-dependently reduced by tesaglitazar (p<0.0001).

CONCLUSION

Although tesaglitazar is no longer in clinical development, these data indicate that dual PPARalpha/gamma agonism may be a useful pharmacological approach to improve the atherogenic dyslipidaemia associated with insulin resistance.

Glycoprotein Ibalpha polymorphism T145M, elevated lipoprotein-associated phospholipase A2, and hypertriglyceridemia predict risk for recurrent coronary events in diabetic postinfarction patients

To explore altered platelet function in recurrent coronary event risk among diabetic postinfarction patients, we investigated a function-altering genetic polymorphism (T145M) in the von Willebrand factor binding region of the platelet glycoprotein Ibalpha (GPIbalpha) subunit. The study comprised diabetic and nondiabetic patients of the Thrombogenic Factors and Recurrent Coronary Events postinfarction study. Cox proportional hazards multivariable modeling, adjusted for significant clinical covariates, was performed using the polymorphism and metabolic, inflammatory, and thrombogenic blood markers. Nondiabetic patients demonstrated risk for elevated lipoprotein-associated phospholipase A(2) (Lp-PLA(2)). In contrast, diabetic patients demonstrated significant and independent risk for the M allele of the T145M polymorphism (MT plus MM versus TT, hazard ratio [HR] 3.73, 95% CI 1.90-7.33, P < 0.001), hypertriglyceridemia (2.91, 1.52-5.56, P = 0.001), and elevated Lp-PLA(2) (2.78, 1.45-5.35, P = 0.002). Joint risk (one, two, or three risk factors) expressed as relative outcome rates (compared with no risk factors) were 2.4, 4.0, and 8.2, respectively. We conclude that the M allele of the T145M polymorphism of the GPIbalpha subunit predicts risk for recurrent coronary events in diabetic postinfarction patients, but not in nondiabetic postinfarction patients, supportive of an important role for platelet hyperactivation in diabetic coronary heart disease.

Polymorphisms in the paraoxonase and endothelial nitric oxide synthase genes and the risk of early-onset myocardial infarction

In young patients, the accumulative burden of traditional cardiovascular risk factors may not be as significant as in an older population. Genetic risk factors were suggested to have a role in the early development of myocardial infarction (MI). However, data about the association between polymorphisms in heart disease-related genes and the early onset of a first MI are limited. In the present study, age at onset of a first MI was related to individual single-nucleotide polymorphisms in each of 18 prespecified candidate genes in a cohort of 814 patients enrolled in the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) Study. Multivariate regression analysis showed in patients who had the high-risk genotypes of paraoxonase 1 (PON1) Q192R and endothelial nitric oxide synthase (eNOS) E298D that ages at onset of a first MI were 1.8 (p = 0.02) and 3.5 years (p = 0.02) earlier than in noncarriers of the genotypes, respectively. Consistently, high-risk genotypes of the PON1 Q192R and eNOS E298D polymorphisms were significantly associated with onset of a first MI at age <50 years (adjusted odds ratio 1.70, p = 0.005, adjusted odds ratio 2.15, p = 0.01, respectively). In conclusion, our findings suggest that high-risk genotypes of the PON1 Q192R and eNOS E298D polymorphisms are independently associated with a significantly earlier occurrence of coronary events.

Documented traditional cardiovascular risk factors and mortality in non-ST-segment elevation myocardial infarction

BACKGROUND

Although documented traditional cardiovascular risk factors (hypertension, diabetes, smoking, and dyslipidemia) increase the risk of developing coronary artery disease, their influence on the treatments and outcomes of patients with non-ST-segment elevation myocardial infarction (NSTEMI) has not been fully elucidated.

METHODS

Using data from the CRUSADE Quality Improvement Initiative, we sought to characterize the effect that the absence of documented traditional risk factors has on inhospital treatments and outcomes in a population of patients with NSTEMI treated in routine practice. We compared clinical characteristics and inhospital outcomes according to the presence and number of risk factors in 74,220 patients with NSTEMI (defined as creatine kinase-MB and/or troponin I/T values above the local upper limit of normal) treated in 476 US hospitals from January 2001 through March 2004.

RESULTS

The 7755 (10.5%) patients with no documented traditional risk factors on admission were less likely to receive short-term guideline-recommended therapies and revascularization procedures. Despite a higher prevalence of normal left ventricular function and insignificant angiographic coronary artery disease, these patients had a slightly higher risk of adjusted inhospital mortality (odds ratio 1.15, 95% CI 1.03-1.29) compared with patients with any combination of risk factors.

CONCLUSIONS

Patients without documented traditional cardiovascular risk factors represent 10.5% of the non-ST-segment elevation myocardial infarction population. Because the absence of documented traditional risk factors does not yield a favorable prognosis, further study is needed to delineate the effects of the interplay between novel and documented traditional risk factors and treatment differences on the outcomes of these patients.

Low-density lipoprotein lowering in type 2 diabetes mellitus: how to know how low to go

PURPOSE OF REVIEW

Getting low-density lipoprotein to the right level in patients with type 2 diabetes should be relatively easy, given the potent pharmacological therapy that is available and the fact that low-density lipoprotein C is typically normal in these patients. Getting it right means getting the target for therapy right, however. The article examines the criteria that should be used to make this choice.

RECENT FINDINGS

In comparing different parameters, three criteria, in particular, need to be taken into account: the on-treatment predictive value of any parameter; the value relative to the population of one parameter compared with another, namely which is more deviant from the norm; and the concurrent level of high-density lipoprotein. The evidence from the low-density lipoprotein-lowering trials indicates that low-density lipoprotein C is not nearly as good as non-high-density lipoprotein C as a guide for the adequacy of low-density lipoprotein lowering, or, better still, apoB, with the apoB/apoA-I ratio being clearly the best of all.

SUMMARY

The evidence from the major clinical trials indicates the best single index of the adequacy of low-density lipoprotein lowering is the apoB/apoA-I ratio. Clinical practice should adapt to clinical evidence and, therefore, guidelines should be based on apolipoproteins rather than the conventional cholesterol indices.

NAD(P)H oxidase polymorphism (C242T) and high HDL cholesterol associate with recurrent coronary events in postinfarction patients

We recently identified a subgroup of postinfarction patients at high-risk for recurrent coronary events defined by inflammation (high C-reactive protein) (CRP) and hypercholesterolemia. Within this subgroup, only elevated high-density lipoprotein cholesterol (HDL-C) from a set of metabolic, inflammatory and thrombogenic blood markers was associated with additional risk. To investigate the role of oxidative stress in this high-risk subgroup, we examined effects on risk of a polymorphism known to affect functional activity of NAD(P)H oxidase, an oxidative enzyme associated with generation of reactive oxygen species. The study population comprised non-diabetic patients of thrombogenic factors and recurrent coronary events (THROMBO) postinfarction study having complete blood marker and genotyping results (N=663) for C242T polymorphism of p22phox subunit (T allele associated with decreased activity). Cox multivariable regression, adjusted for significant clinical covariates, was used to assess within-subgroup risk associated with blood markers and polymorphism. In addition to elevated HDL-C (hazard ratio, 95% CI and p-value; 2.62, 1.05-6.55 and 0.039), significant independent risk was found for C242T (CC versus CT plus TT: 3.14, 1.34-7.35 and 0.0084). We conclude that oxidative stress plays a significant role in establishment of risk for recurrent coronary events in a high-risk subgroup of postinfarction patients defined by inflammation and hypercholesterolemia.

Significance of Determining Levels of Apolipoproteins A-I and B in the Diagnostics and Assessment of Lipid-Related Atherogenic Risk in Hyperalpha-Lipoproteinemia, Hypocholesterolemia and Hypo-Hdl-Cholesterolemia

The significance of determining apolipoproteins apoB and apoA-I and their correlation with lipid status parameters were tested in hyperalpha-lipoproteinemia (30 women), hypocholesterolemia (10 men) and hypo-HDL-cholesterolemia (15 women and 21 men). Control groups were 20 normolipidemic men and women, each. ApoA-I showed positive correlation with HDL-cholesterol in hyperalpha-lipoproteinemia, with total and HDL-cholesterol in hypocholesterolemia, and with total and LDL-cholesterol in females with hypo-HDL-cholesterolemia, and negative correlation with cholesterol ratios only in hypocholesterolemia. ApoB showed a positive correlation with total and LDL-cholesterol in all groups, and with cholesterol ratios in hyperalpha-lipoproteinemia and hypo-HDL-cholesterolemia. The apoB/apoA-I ratio, correlating with the majority of lipid parameters, and with the highest percentage of pathological values in all tested groups, was singled out as the most sensitive parameter for the evaluation of lipid-related atherogenic risks.

Differential impact of plasma triglycerides on HDL-cholesterol and HDL-apo A-I in a large cohort

OBJECTIVES

To examine the relationship between plasma triglycerides (TG) to HDL-cholesterol (HDL-C) or HDL apo A-I.

DESIGN AND METHODS

Bivariate and multiple linear regression analyses in a large cohort of 1886 subjects.

RESULTS

Higher plasma TG levels were associated with lower concentrations of both HDL-C and HDL-apo A-I. However, the HDL-C/HDL-apo A-I ratio was inversely correlated with plasma TG indicating that the overall composition of the HDL changed as plasma TG changed. Plasma TG levels contributed to 15.9% of the variance of the HDL-C/HDL-apo A-I ratio, whereas gender, HDL-TG, LDL-TG, body mass index and plasma apo B levels represented between 0.15% and 2.21% of this variance.

CONCLUSIONS

These results indicate that increasing levels of plasma TG result in greater reduction in HDL-C levels than in HDL-apo A-I and this might explain, at least in part, the differences that have been observed in the magnitude of the association of HDL-C versus HDL-apo A-I with the risk of cardiovascular disease.

Association between inflammation, lipid and hemostatic factors in patients with stable angina

INTRODUCTION

Dyslipidemia and thrombotic processes are both clearly involved in atherogenesis and its secondary complications. Moreover, inflammation has also been shown to play an important role in the pathophysiology of atherosclerosis. Our objective was to determine the association between inflammation, lipids and thrombosis in a group of patients with stable angina.

PATIENTS AND METHODS

295 patients (217 males and 78 females) with a mean age of 65.69+/-11.24 years. Levels of C-reactive protein, total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, lipoprotein(a), apolipoproteins A1 and B100, fibrinogen and D-dimer were determined for each.

RESULTS

Arithmetic and geometric means of C-reactive protein in the sample were 10.7 and 1.4 mg/l, respectively. Distributing the sample by quartiles of C-reactive protein, we found a positive correlation between C-reactive protein, fibrinogen and D-dimer levels (p<0.000), and an inverse correlation for HDL cholesterol and apolipoprotein A1 (p<0.000). In multivariate analysis, fibrinogen (p<0.000) and D-dimer (p<0.01) levels were independently associated with high levels of C-reactive protein. Of the lipid factors, only apolipoprotein A1 (p<0.000) was independently and inversely associated with high levels of C-reactive protein.

CONCLUSIONS

These data confirm the association between prothrombotic and inflammatory states and suggest the anti-inflammatory effect of apolipoprotein A1.

Apolipoprotein A1 and B

This article reviews the evidence showing that apolipoprotein (apo) B and A-1 are superior to the conventional cholesterol indices as analytes in laboratory practice, indices of the lipoprotein-related risk for vascular disease, and measures of the adequacy of low-density lipoprotein-lowering therapy.

The role of enzyme-linked immunosorbent assay D-dimer in patients with acute coronary syndrome presenting with normal cardiac enzymes

Plasma D-dimer levels, the primary degradation product of cross-linked fibrin, are elevated in acute coronary syndrome (ACS). However, the role of D-dimer in patients presenting to the Emergency Department with ACS and normal cardiac enzymes is unknown. We conducted a prospective, observational study in the Emergency Department of a major tertiary university-affiliated center. The study included 124 patients presented to the Emergency Department with ACS and normal cardiac enzymes. Blood samples were collected and assayed for D-dimer levels with the enzyme-linked immunosorbent assay (ELISA) test. The D-dimer values were correlated with the clinical, laboratory and electrocardiographic findings on admission, as well as with the catheterization findings and with hospital length of stay. ELISA D-dimer levels positively correlated with sex, hypertension and smoking (r = -0.27, P = 0.002; r = 0.33, P = 0.0002; and r = -0.24, P = 0.007, respectively). Significant correlation was also observed between ELISA D-dimer and cardiac medications including beta-blocker (r = 0.22, P = 0.01), aspirin (r = 0.18, P = 0.04), nitrate (r = 0.20, P = 0.002), acute phase reactants fibrinogen (r = 0.45, P = 0.0001) and C-reactive protein (r = 0.29, P = 0.004), ischemic electrocardiographic changes (r = 0.21, P = 0.02) and length of stay (r = 0.29, P = 0.001). The catheterization findings were also correlated with the ELISA D-dimer levels (r = 0.31, P = 0.02). The ELISA D-dimer test may add important clinical data concerning patients with ACS and normal cardiac enzymes.

apoB/apoA–I ratio is related to femoral artery plaques and is predictive for future cardiovascular events in healthy men

OBJECTIVES

The aim of the present study was to investigate the association between serum concentrations of apoB, apoA-I and the apoB/apoA-I ratio and future cardiovascular events in a group of healthy 58-year-old men during 6.6 years of follow-up. A further aim was to investigate the concentrations of apoB, apoA-I and the apoB/apoA-I ratio to the association of plaque occurrence in the carotid and femoral arteries.

BACKGROUND

Previous studies have shown that the apoB/apoA-I ratio is an important cardiovascular risk factor, whereas the association between apoB/apoA-I ratio and presence of atherosclerotic plaques in the carotid and femoral arteries has been less investigated.

METHODS

The carotid and femoral arteries were examined by high-resolution B-mode ultrasound in 391, 58-year-old men identified by screening in the city of Göteborg, Sweden. Assessment of plaque occurrence and measurement of apolipoproteins (apoA-I and apoB) was performed.

RESULTS

Subjects with an apoB/apoA-I ratio >/=0.9 had a significantly increased risk to suffer a cardiovascular event during 6.6 years of follow-up (OR 3.07, 95% CI 1.22-7.71), while no difference in risk for cardiovascular events was observed for subjects with LDL cholesterol >3.4 mmol/L compared to subjects <3.4 mmol/L (OR 1.04, 95% CI 0.37-2.46). A greater risk for plaques in the femoral artery was also observed in subjects with an apoB/apoA-I ratio >/=0.9 compared to subjects <0.9 (OR 3.06, 95% CI 1.22-7.70). In a multiple logistic regression model, both elevated apoB/apoA-I ratio and plaque occurrence in the femoral artery were of significant importance for cardiovascular events during follow-up.

CONCLUSIONS

The results showed that the apoB/apoA-I ratio was associated with arteriosclerosis in the femoral artery, and predicted future cardiovascular events. These observations, and the fact that apoB and apoA-I can be measured in the non-fasting state with high precision, in combination with the finding that LDL cholesterol did not predict cardiovascular disease, support results from other studies that the apoB/apoA-I ratio may be a superior risk marker for cardiovascular disease.

Plasma markers of activated hemostasis in the early diagnosis of acute coronary syndromes

BACKGROUND

Because acute coronary syndromes (ACS) are caused by intracoronary thrombosis, plasma markers of coagulation have relevance for early diagnosis.

AIMS AND OBJECTIVES

To provide a critical review of these studies and specific attempts to close the diagnostic time gap left by traditional plasma markers of heart injury.

METHODS

Studies of ACS patients, with at least one control group, were included when blood samples were taken within 24 h after first symptoms prior to medication or intervention. Special attention was paid to studies reporting diagnostic performance, or combination of several markers into a single diagnostic index.

RESULTS

Markers with short plasma half-life (FPA, TAT, etc.) reflect ongoing thrombosis and may identify patients at increased risk. Markers with longer half-life (F1+2, D-Dimer, etc.) may be more useful to indicate a single acute thrombotic event. However, results are highly variable and depend on sampling time, clot property, degree of coronary obstruction and physiological condition. Early diagnostic performance of hemostatic markers was poor even when combined with heart injury markers.

CONCLUSIONS

Early measurement of hemostatic plasma markers in ACS patients provides pathophysiological information and may be helpful in risk stratification or to monitor anticoagulant therapy, but does not seem useful in routine clinical diagnosis of ACS.

Apolipoprotein A-I and risk for cardiovascular diseases

Increased concentrations of high-density lipoprotein (HDL) cholesterol have been closely associated with decreased risk of future cardiovascular disease. This protective effect of HDL has been mainly attributed to its involvement in reverse cholesterol transport. More recently, it has been suggested that apolipoprotein A-I (apoA-I), the major protein component of HDL, possesses nearly identical information as HDL in terms of risk prediction for future cardiovascular disease. This makes apoA-I a very attractive biomarker candidate for implementation into clinical practice, taking into account its analytical advantages. This review summarizes our current knowledge based on observations from recent studies, with emphasis on potential pathophysiologic mechanisms of action and on the clinical utility of apoA-I as a predictor of cardiovascular risk.

High Lipoprotein-Associated Phospholipase A2 Is a Risk Factor for Recurrent Coronary Events in Postinfarction Patients

Background: Recent studies demonstrate that lipoprotein-associated phospholipase A2 (Lp-PLA2) is a risk factor for cardiovascular disease presumably deriving from generation of proinflammatory and proatherogenic species through its hydrolytic activity on lipoprotein-associated phospholipids. The goal of this study was to assess the relationship of Lp-PLA2 with a set of thrombogenic, lipid, inflammatory, and metabolic blood markers and to determine whether plasma Lp-PLA2 is a risk factor for recurrent coronary events in postinfarction patients.

Methods: Factor analysis on the set of blood markers and Lp-PLA2 was performed for 766 patients of the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) postinfarction study. Recurrent coronary event risk was assessed as a function of blood marker concentrations and Lp-PLA2 by Cox proportional hazards multivariable regression adjusted for significant clinical covariates.

Results: Factor analysis revealed that Lp-PLA2 was associated with one factor dominated by cholesterol and apolipoprotein B and another factor dominated by HDL-cholesterol and triglycerides, with little association with an inflammatory factor dominated by C-reactive protein. Multivariable analysis demonstrated as significant and independent predictors of risk of secondary coronary events only apolipoprotein B in a model without Lp-PLA2 (hazard ratio, 1.66; 95% confidence interval, 1.14–2.40) and only Lp-PLA2 in a model with Lp-PLA2 included [1.90 (1.31–2.75)].

Conclusions: Lp-PLA2 is a significant and independent predictor of risk for recurrent coronary events in postinfarction patients, and Lp-PLA2 is related to both hypercholesterolemia and high triglyceride–low HDL dyslipidemia in this study population.

D-dimer is not a long-term prognostic marker following acute cerebral ischemia

Recent evidence indicates a possible role of D-dimer in the early diagnosis of ischemic stroke subtypes. Whether D-dimer can also predict the long-term outcome following ischemic stroke is controversial. To define the prognostic role of D-dimer, patients hospitalized after an acute ischemic cerebrovascular event underwent D-dimer measurement (Liatest D-D; normal level < 0.50 microg/ml) on admission and were followed up for recurrent cerebrovascular events, occurrence of other cardiovascular events, and mortality. We enrolled 96 patients (mean age 74.9 years, 42 men). Mean follow-up was 61.5 months; 47 (48.5%) patients died, 23 (48.9%) because of a vascular event. There was no difference in mean D-dimer levels between dead patients and survivors (1.68 and 1.63 microg/ml, P = NS), but the mortality risk was higher with D-dimer of at least 0.50 microg/ml (odds ratio, 5.32; 95% confidence interval, 1.79-15.84). After adjustment for age and stroke subtype, the odds ratio was not significant. Mean D-dimer was similar between patients with and without a new vascular event (1.43 and 1.68 microg/ml, P = NS), and D-dimer of at least 0.50 microg/ml was not predictive of an increased risk of subsequent events. D-dimer levels measured in the acute phase after an acute cerebrovascular event probably do not predict the long-term clinical outcome.

Can haematological tests predict cardiovascular risk? The 2005 Kettle Lecture*

The risk of venous or arterial thrombosis is routinely assessed by clinical variables (risk factors) supplemented by measurement of blood lipids and glucose for arterial thrombotic events. Haematological tests that might play a role in risk prediction include haemostatic variables, haematocrit and inflammatory markers (erythrocyte sedimentation rate, plasma viscosity, white cell count). Recent epidemiological studies of these phenotypes and related genotypes are reviewed. For the risk prediction of first venous thrombosis, screening for thrombophilias in 'high-risk' situations does not appear clinically effective or cost-effective; with the possible exception of women considering oral hormone replacement therapy. General screening after a first venous event to predict recurrence (or risk in asymptomatic relatives) does not appear effective; with the possible exception of d-dimer, which requires further study. For risk prediction of first arterial thrombosis, screening adds little to prediction by current clinical risk scores. Screening of persons after a first arterial event, or with atrial fibrillation (e.g. with D-dimer for stroke prediction), requires further study. In conclusion, haematological tests have very limited roles in the prediction of cardiovascular risk, and should only be used according to evidence-based guidelines. The need for management studies is highlighted.

The apoB/apoA-I ratio: a strong, new risk factor for cardiovascular disease and a target for lipid-lowering therapy--a review of the evidence

During the last several years interest has focused on the importance of the lipid-transporting apolipoproteins--apoB transports all potentially atherogenic very low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL) and LDL particles, and apoA-I transports and acts as the major antiatherogenic protein in the HDL particles. The evidence for the apoB/apoA-I ratio being a strong, new risk factor for cardiovascular (CV) disease and a target for lipid-lowering therapy is reviewed. Results from clinical prospective studies and lipid-lowering trials in healthy subjects and in patients with different clinical manifestations of atherosclerosis are reported. Risk of nonfatal and fatal myocardial infarction and stroke, and manifestations of atherosclerosis documented by angiographic, ultrasound and other techniques has been related to conventional lipids and apolipoproteins (apo). The cholesterol balance determined as the apoB/apoA-I ratio has repeatedly been shown to be a better marker than lipids, lipoproteins and lipid ratios. The results indicate that the apoB/apoA-I ratio is a simple, accurate and new risk factor for CV disease--the lower the apoB/apoA-I ratio, the lower is the risk. Guidelines should be developed in order to recognize the important clinical risk information embedded in the apoB/apoA-I ratio.

Errors that result from using the TC/HDL C ratio rather than the apoB/apoA-I ratio to identify the lipoprotein-related risk of vascular disease

The objective of this analysis was to demonstrate the frequency and extent of error that results from using the TC/HDL C ratio rather than the apoB/apoA-I ratio to estimate the lipoprotein-related risk of vascular disease within 94,667 men and 75,675 women in the Apoprotein-related Mortality Risk (AMORIS) cohort. The odds ratio (OR) for the risk of fatal myocardial infarction was determined for 1 SD change in the apoB/apoA-I ratio and all the conventional cholesterol ratios--TC/HDL C ratio, LDL C/HDL C ratio, non-HDL C/HDL C ratio. In both men and women, the apoB/apoA-I ratio was significantly greater than any of the cholesterol ratios, which, in fact, differed little. Therefore, the apoB/apoA-I ratio was taken as the most accurate index of the lipoprotein-related risk of vascular disease. Using Receiver Operating Characteristic analysis, it was demonstrated that the diagnostic accuracy of the apoB/apoA-I ratio was significantly greater than any cholesterol ratio in those with an LDL cholesterol <3.6 mmol L(-1) compared to those with an LDL cholesterol >3.6 mmol L(-1). Indeed, the difference between the apoB/apoA-I OR compared with the TC/HDL C OR progressively widened as risk increased. This suggests that the advantage of the apoB/apoA-I ratio is greatest in the population at highest risk. The distribution of subjects by quintiles showed in both genders that whilst agreement was greatest at the extremes, even at these points there was substantial discordance between the TC/HDL C and the apoB/apoA-I ratios. Within the middle of the distribution, less than 50% of the values were concordant. Finally, when comparing the ORs, the TC/HDL C ratio underestimated risk in 69.4% of male subjects and overestimated risk in 26.1% of male subjects, whereas in the female subjects, the TC/HDL C ratio underestimated risk in 84.9% of the subjects and overestimated risk in 12.0%. Thus, using the conventional cholesterol ratios rather than the apoB/apoA-I ratio results in frequent and substantial error in the estimation of the lipoprotein-related risk of vascular disease.

Apolipoprotein-B, low-density lipoprotein cholesterol, and the long-term risk of coronary heart disease in men

We examined whether plasma apolipoprotein-B (apo-B) levels add further information on the risk of coronary heart disease (CHD) after taking into account low-density lipoprotein (LDL) cholesterol concentrations and other traditional risk factors. Among 2,072 CHD-free men from the Québec Cardiovascular Study at entry and followed for 13 years, 230 had a first CHD event (CHD death or nonfatal myocardial infarction). Increased apo-B (tertile 1 vs 3) levels were associated with a significant increased risk of CHD after adjustment for nonlipid and lipid risk factors other than LDL cholesterol levels (relative risk 1.89, 95% confidence interval 1.31 to 2.73). High plasma LDL cholesterol concentrations (tertile 1 vs 3) were also associated with an increased risk of CHD independently of nonlipid and lipid risk factors (relative risk 2.02, 95% confidence interval 1.44 to 2.84). However, apo-B levels modulated to a significant extent the risk of CHD associated with increased concentrations of LDL cholesterol (>/=4.3 mmol/L). For instance, among men with high LDL cholesterol levels, those with an apo-B level <128 mg/dl were not at increased risk for CHD (relative risk 1.53, 95% confidence interval 0.89 to 2.62). In contrast, high levels of apo-B and LDL cholesterol were associated with a significant twofold increased risk of CHD (p <0.001). Receiver-operating curve analysis also indicated that plasma apo-B levels improved the ability to discriminate incident CHD cases among patients with high LDL cholesterol levels compared with a model based on LDL cholesterol levels (p = 0.04). In conclusion, plasma apo-B levels modulated the risk of CHD associated with LDL cholesterol over a 13-year follow-up.

Soluble tissue factor is a candidate marker for progression of microvascular disease in patients with Type 2 diabetes

OBJECTIVE

To determine the relationship between abnormalities in blood coagulation and prevalent or incident cardiovascular complications in Type 2 diabetes.

DESIGN AND METHODS

Prospective cohort study of 128 patients with Type 2 diabetes in whom blood samples were collected at baseline and after 1 year of follow-up. All cardiovascular complications at baseline and follow-up were recorded. Forty-three healthy, age-matched subjects served as a control group.

RESULTS

Logistic analysis revealed an independent relationship between soluble tissue factor (TF) and microvascular disease [per pg mL(-1) TF: Exp(B) = 1.008; CI(95%)1.002-1.014], or neurogenic disease [Exp(B) = 1.006; CI(95%)1.001-1.011]. The highest levels of soluble TF were observed in patients with microvascular and neurogenic disease (P < 0.001). Patients with Type 2 diabetes having a soluble TF concentration >300 pg mL(-1) are at a 15-fold higher risk for the presence of microvascular disease and at a 10-fold higher risk for the presence of neurogenic disease compared with the patients with concentrations below 100 pg mL(-1). Soluble TF was correlated with tissue type plasminogen activator, von Willebrand factor antigen, systolic blood pressure and age. Levels of F1' + 2, D-dimer, FVIII activity, t-PA and vWFag were not different among patients with micro-, macro- or neurogenic complications compared with patients without those complications. Forty-eight new micro-, macro- and/or neurogenic complications were diagnosed after 1 year follow-up. With the exception of higher F1 + 2 levels after 1 year all other markers remained unchanged. A trend toward higher soluble TF levels was observed in patients with new microvascular events (P = 0.056).

CONCLUSIONS

Soluble TF is associated with existing microvascular and neurogenic complications in patients with Type 2 diabetes and is a candidate marker for progression of microvascular disease.

Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel

There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

Ad Hoc percutaneous coronary interventions in patients with stable coronary artery disease—A study of prevalence, safety, and variation in use from the American College of Cardiology National Cardiovascular Data Registry (ACC-NCDR®)

OBJECTIVE

To utilize the American College of Cardiology National Cardiovascular Data Registry (ACC-NCDR) to monitor the performance and safety of ad hoc PCIs.

BACKGROUND

The performance of ad hoc PCI remains controversial. Patients' preference, cost, and vascular access issues favor an ad hoc strategy. Adequate time for thoughtful decision-making, scheduling complexity, informed consent, and physician reimbursement favor PCI on a subsequent day.

METHODS

We analyzed results in 68,528 patients with stable angina entered in the ACC-NCDR from 2001-2003. Ad hoc PCI was evaluated in many clinical and nonclinical subgroups. A multivariable analysis was performed to determine whether ad hoc PCI had an independent relationship with complications or procedure success.

RESULTS

Overall, 60.6% of patients underwent ad hoc PCI. There was no difference in ad hoc PCI mortality, renal failure, or vascular complications from staged PCI. A lower percentage of patients at high vs. low risk and with vs. without renal failure underwent ad hoc PCIs (58.6% vs.63.0% and 50.7% vs. 60.9% respectively). There was wide variation in the performance of ad hoc PCIs according to payer (70.2-60.3%), hospital PCI volume (67-50.2%), hospital owner (89.7-59.6%), and geographic area (75.5-47.4%). Ad hoc PCI per se was not independently related to PCI success or complications.

CONCLUSIONS

PCI success was related to patient/lesion related factors and not to the performance of ad hoc PCIs per se. Although ad hoc PCI can be performed in more patients than at present, this strategy will never be possible in all patients at all times.

Serum Lipid Profile Constituents as Markers of Cardiovascular Morbidity in Patients on Chronic Hemodialysis

We designed the present case-control study in order to examine the validity of apolipoprotein (apo) A-I, B, apoB/apoA-I ratio and Lp(a) as alternative markers of cardiovascular morbidity in end-stage renal disease (ESRD) patients undergoing chronic hemodialysis (HD). Twenty-five HD patients (18 males, mean age 63, range 52–69 years) comprised the group with prevalent cardiovascular disease (CVD) and 50 HD patients (35 males, mean age 62, range 40–77 years) with non evident cardiovascular disease history constituted the second study group. Patients with CVD had significantly higher concentrations of serum apoB, apoB/apoA-I ratio and Lp(a), and lower levels of apoA-I compared to patients without incident CVD. All three parameters studied were correlated with cardiovascular morbidity, i.e. apoA-I negatively and apoB and apoB/apoA-I ratio positively (r = −0.6, P < 0.05; r = 0.659, P < 0.01; and r = 0.614, P < 0.01, respectively). Furthermore, logCRP exhibited as well a significant positive correlation with cardiovascular morbidity (r = 0.704, P < 0.001), not this being the case for Lp(a) which was not found to exhibit such a correlation (r = 0.05, P = NS). Among them, apoB and apoB/apoA-I ratio exhibited the characteristics most coherent to CVD. The age- and sex-adjusted OR for the presence of CVD was 2.3 and 2.0, respectively, which remained independent of any confounding effect of inflammation. In conclusion, serum apoB levels and apoB/apoA-I ratio exhibit characteristics of credible independent markers of in HD patients.

Elevated HDL is a risk factor for recurrent coronary events in a subgroup of non-diabetic postinfarction patients with hypercholesterolemia and inflammation

Recent studies demonstrate important roles for inflammation in development of atherosclerosis with current attention focusing on interactions of inflammation with traditional lipoprotein risk factors. Since the nature of such relationships is largely unknown, we sought to investigate interactions of inflammation with hyperlipidemia in generating cardiovascular risk in a way that would allow recognition of such interactions whether anticipated or not. Thus, we searched for subgroups at high risk for recurrent coronary events in 767 non-diabetic postinfarction patients using an exploratory three-dimensional graphical screening technique with previously established factor analysis-derived inflammatory and lipoprotein-related factors. Results indicated a high-risk patient subgroup defined by factor interaction that was best characterized clinically by high levels of C-reactive protein (CRP) and total cholesterol. Kaplan-Meier and Cox multivariate analysis confirmed high-risk. Additionally, within-subgroup risk related to metabolic, inflammatory, and thrombogenic blood markers was assessed using Cox analysis with results showing only elevated HDL as a significant and independent predictor of risk with hazard ratio, 2.24 (95% CI; 1.12, 4.49; p = 0.023). We conclude that in non-diabetic postinfarction patients, elevated HDL is predictive of risk of recurrent coronary events within a subgroup of patients characterized by simultaneous elevations in serum CRP and total cholesterol.

Atherosclerotic risk genotypes and recurrent coronary events after myocardial infarction

The association of a group of prespecified atherosclerotic risk genotypes with recurrent coronary events (coronary-related death, nonfatal myocardial infarction, or unstable angina) was investigated in a cohort of 1,008 patients after infarction during an average follow-up of 28 months. We used a carrier-ship approach with time-dependent survivorship analysis to evaluate the average risk of each carried genotype. Contrary to expectation, the hazard ratio for recurrent coronary events per carried versus noncarried genotype was 0.89 (95% confidence interval 0.80 to 0.99, p = 0.03) after adjustment for relevant genetic, clinical, and environmental covariates. This hazard ratio, derived from the 7 prespecified genotypes, indicated an average 11% reduction in the risk of recurrent coronary events per carried versus noncarried genotype. At 1 year after hospital discharge, the cumulative probability of recurrent coronary events was 26% in those who carried < or =1, 20% for those with 2 to 4, and 13% for those with > or =5 of these genotypes (p = 0.02). This unexpected risk reversal is a likely consequence of changes in the mix of risk factors in pre- and postinfarction populations. In conclusion, this under appreciated, population-based, risk-reversal phenomenon may explain the inconsistent associations of genetic risk factors with outcome events in previous reports involving coronary populations with different risk attributes.

Comparison of apolipoprotein B and plasma lipids as targets for lipid lowering treatment

OBJECTIVE

To assess the discrepancies between LDL-cholesterol and apo B targets in patients at risk for vascular disease; namely, those with diabetes or hypertriglyceridemia and those with triglycerides <1.7 mmol/L and normal glucose homeostasis.

METHODS

Lipid clinic patients were divided into two groups: Group 1 consisted of 182 patients whose triglyceride levels were >1.7 mmol/L or who had impaired fasting glucose or type 2 diabetes. In Group 2, there were 42 patients with triglycerides <1.7 mmol/L and normal glucose homeostasis. LDL-cholesterol and apo B were estimated during lipid clinic visits with patients on appropriate lipid lowering therapy.

RESULTS

46% of the patients in Group 1 who reached the high risk LDL-cholesterol target of <2.5 mmol/L did not reach apo B target of <0.9 g/L, while in Group 2, only 19% of those who reached the LDL-cholesterol target had apo B >0.9 g/L.

CONCLUSION

Our findings demonstrate that a large percentage of patients with hypertriglyceridemia or impaired glucose tolerance, treated with lipid lowering agents, reach the LDL-cholesterol but not the apo B treatment targets.

Negative impact of depression on outcomes in patients with coronary artery disease: mechanisms, treatment considerations, and future directions

Depressive symptoms are common in coronary artery disease (CAD) patients, and are associated with increased cardiac risk. Although an important relation exists between depression and CAD prognosis, the underlying pathophysiological mechanisms are poorly understood. Additionally, evidence including the recently published ENRICHD (Enhancing Recovery in Coronary Heart Disease Patients) trial suggests that depression treatments do not lower recurrent cardiac risk. The reason for the observed lack of benefit with depression treatment in CAD patients is unclear. In this review, we discuss the impact of depression in CAD patients, the possible mechanisms involved, the studies that have examined the effects of psychological and antidepressant therapies on recurrent cardiac events, and the direction that future research should take.

Risk factors for cardiovascular event recurrence in the Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND

Numerous studies have identified risk factors and markers associated with incidence of cardiovascular disease (CVD). However, few studies have examined whether established risk factors, novel blood markers, carotid ultrasonography, or ankle-brachial index can predict recurrent CVD events.

METHODS AND RESULTS

We analyzed the relation of established risk factors and markers of atherosclerosis with the risk of recurrent CVD in 766 participants. Over a mean of 8.7 years of follow-up, 70 women and 243 men had a recurrent CVD event (85.3% coronary heart disease and 23.7% stroke). Adjusting for age and sex, this study found that established risk factors were associated with recurrent CVD events in the anticipated direction. Being in the highest (vs lowest) quartiles of lipoprotein (a), fibrinogen, white blood cells, and creatinine at baseline were associated with 47%, 69%, 65%, and 81%, respectively, greater risk of a CVD event, and being in the highest quartile of albumin was associated with 39% lower risk. Being in the highest (vs lowest) quartile of carotid intima-media thickness (IMT) was associated with a doubling of risk, and having carotid plaque with acoustic shadowing (vs having no plaque) was associated with 83% increased risk of a CVD event. After adjustment for established risk factors, creatinine, albumin, and carotid IMT in the highest quartile (vs lowest quartile) and carotid plaque with acoustic shadowing (vs no plaque) were independently associated with recurrent CVD events.

CONCLUSION

Established risk factors, but only a few of novel risk factors and markers, were independent predictors of recurrent CVD events.

Effects of intermittent fasting on serum lipid levels, coagulation status and plasma homocysteine levels

BACKGROUND

During Ramadan, Muslims fast during the daylight hours for a month. The duration of restricted food and beverage intake is approximately 12 h/day which makes Ramadan a unique model of intermittent fasting. Many physiological and psychological changes are observed during Ramadan that are probably due to the changes in eating and sleeping patterns.

METHODS

Serum total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), prothrombin time, activated partial thromboplastin time (aPTT), plasma fibrinogen, D-dimer and homocysteine levels were measured in 24 healthy fasting volunteers (12 females, 12 males) aged 21-35 years. Venous blood samples were taken 1 week before Ramadan, on the 21st day of Ramadan and 20 days after Ramadan.

RESULTS

No significant changes were observed on serum total cholesterol, triglycerides and LDL levels. HDL levels were significantly elevated during Ramadan (p < 0.001) and 20 days after Ramadan (p < 0.05). Prothrombin time, aPTT, fibrinogen and D-dimer levels were in the physiologic limits in all samples but D-dimer levels were significantly low at the end of Ramadan in comparison to pre- and post-fasting levels (p < 0.001). Homocysteine levels, being still in reference ranges, were low during Ramadan (p < 0.05) and reached the pre-fasting levels after Ramadan.

CONCLUSION

Our results demonstrate that intermittent fasting led to some beneficial changes in serum HDL and plasma homocysteine levels, and the coagulation status. These changes may be due to omitting at least one meal when the body was particularly metabolically active and possibly had a low blood viscosity level at the same time. We conclude that intermittent fasting may have beneficial effects on hemostatic risk markers for cardiovascular diseases.

Apolipoprotein B determines risk for recurrent coronary events in postinfarction patients with metabolic syndrome

The adult treatment panel III (ATP III) of the National Cholesterol Education Program recognizes metabolic syndrome (MS) as a secondary target for risk-reduction therapy given the well-known increase in risk of cardiovascular disease (CVD) by all MS components. We investigated potential CVD risk arising from 17 laboratory variables in postinfarction patients with MS by identifying such patients from the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) study using slightly modified ATP III criteria for MS. This gave 272 patients with MS out of a total of 766 postinfarction patients without history of diabetes. Comparison between non-MS and MS patients using Kaplan-Meier analysis revealed no difference in outcome between groups. Additionally, a proportional hazards model applied to dichotomized laboratory parameters demonstrated only apoB as a significant predictor of risk for recurrent coronary events in MS patients with hazard ratio, 1.97 (95% CI; 1.08, 3.60; P < 0.05). We conclude that there is no difference in outcomes between non-MS and MS postinfarction patients; that apoB is significantly associated with risk for recurrent coronary events in postinfarction patients with MS; that further studies would be needed to recommend the routine determination of apoB in these patient groups.

Role of ELISA D-dimer test in patients with unstable angina pectoris presenting at the emergency department with a normal electrocardiogram

Patients with unstable angina pectoris and acute myocardial infarction have higher than normal D-dimer levels. The aim of the study was to determine the value of the D-dimer test in patients with unstable angina pectoris and a normal electrocardiogram on presentation at the emergency department. The study sample included 81 patients who met these criteria. Blood samples collected at admission were subjected to ELISA D-dimer. Findings were correlated with coronary risk factors, use of cardiac medications, blood levels of acute phase reactants (fibrinogen and C-reactive protein), cardiac enzymes levels, length of hospital stay, and catheterization findings. ELISA D-dimer levels were statistically significantly correlated with cardiac risk factors, namely male sex, older age, smoking, and hypertension (r = 0.25, P = 0.02; r = 0.43, P = 0.0001; r = 0.26, P = 0.03; r = 0.35, P = 0.002, respectively), in addition to use of cardiac medications (beta blockers, aspirin, nitrates), levels of acute phase reactants, length of stay, and catheterization findings. On multivariate analysis, only D-dimer level, age, and sex were predictors of length of stay (P = 0.018). The study suggests that D-dimer levels at admission to the emergency department may serve as an additional tool to predict the magnitude of unstable angina pectoris in patients with a normal electrocardiogram.

Evidence for a complex risk profile in obese postmenopausal Turkish women with hypertriglyceridaemia and elevated apolipoprotein B

The aim of the present study was to examine possible pathophysiological relationships among a wide array of proatherogenic risk factors in postmenopausal women. Fasting lipids, apoB (apolipoprotein B), BMI (body mass index) and waist circumference were measured in 178 women (59.4±7.2 years) from the Turkish Adult Risk Factor Study. Fasting levels of complement C3, insulin, SHBG (sex hormone-binding globulin), cortisol, oestradiol, testosterone and DHEA-S (dehydroepiandrosterone sulphate) were also determined. This is the first study to examine the relationships of all these variables with apoB. In the first of two different approaches, three groups of obese women were compared. Group 1 comprised women who were normolipidaemic with normal apoB; group 2, women who were hypertriglyceridaemic, but with normal apoB; and group 3, women who were hypertriglyceridaemic with elevated apoB. Complement C3, fasting insulin and glucose were significantly higher and HDL-C (high-density lipoprotein-cholesterol) and SHBG levels were significantly lower in group 3 than in group 1. In the former group, the testosterone/SHBG ratio tended to be higher, indicating more free testosterone, than in group 1. The mean risk score in group 3 and the odds ratio for coronary disease by logistic regression analysis were significantly higher, 2.56 (confidence intervals, 1.12–5.85; P=0.026), compared with the two other groups combined. In examining the whole group, apoB levels correlated significantly with a wider array of pro-atherogenic risk factors than did LDL-C (low-density lipoprotein-cholesterol), particularly being linked to complement C3 and glucose, as well as the risk score. Complement C3 demonstrated the widest associations and was significantly linked with BMI, waist circumference, insulin, glucose, fibrinogen, triacylglycerols (triglycerides) and apoB and was inversely correlated with HDL-C and SHBG. SHBG was also correlated inversely with a wide spectrum of risk variables. In summary, in Turkish women, apoB was linked with a complex array of proatherogenic risk factors, and hypertriglyceridaemia with elevated apoB was associated with a higher risk of coronary disease.

Abdominal obesity and dyslipidemia in the metabolic syndrome: importance of type 2 diabetes and familial combined hyperlipidemia in coronary artery disease risk

Regional body fat distribution has an important influence on metabolic and cardiovascular risk factors. Increased abdominal (visceral) fat accumulation is a risk factor for coronary artery disease (CAD), dyslipidemia, hypertension, stroke, and type 2 diabetes. The recent emphasis on treatment of the dyslipidemia of the metabolic syndrome (hypertriglyceridemia, reduced high-density lipoprotein, and increased small, dense low-density lipoprotein particle number) has compelled practitioners to consider lipid-lowering therapy in a greater number of their patients, as one in two individuals over age 50 has the metabolic syndrome. Individuals with the metabolic syndrome typically have normal low-density lipoprotein cholesterol levels, and current lipid-lowering guidelines may underestimate their cardiovascular risk. Two subgroups of patients with the metabolic syndrome are at particularly high risk for premature CAD. One, individuals with type 2 diabetes, accounts for 20-30% of early cardiovascular disease. The second, familial combined hyperlipidemia, accounts for an additional 10-20% of premature CAD. Familial combined hyperlipidemia is characterized by the metabolic syndrome in addition to a disproportionate elevation of apolipoprotein B levels. The measurement of fasting glucose and apolipoprotein B, in addition to the fasting lipid profile, can help to estimate CAD risk in patients with the metabolic syndrome.

Determinants of ELISA D-dimer sensitivity for unstable angina pectoris as defined by coronary catheterization

Unstable angina pectoris is associated with elevated D-dimer levels. However, the operating characteristics (sensitivity, specificity, positive and negative predictive value) of the D-dimer assay for the diagnosis of coronary artery disease (CAD) are unknown. Using a prospective, observational design, we collected blood from 54 patients with unstable angina pectoris at admission and assayed for ELISA D-dimer levels. The sensitivity, specificity, and negative and positive prediction values for angiographically determined coronary artery disease were calculated at multiple discriminate levels. All patients underwent coronary catheterization. A statistically significant correlation was noted between ELISA D-dimer levels and age, male sex, hypertension, use of beta-blocker, fibrinogen levels and catheterization findings. No correlation was noted between ELISA D-dimer levels and degree of the coronary artery disease. Best results were provided at a discriminate level of 270 ng/ml, with sensitivity 70%, negative predictive value 72%, and overall accuracy 67%. All discriminate levels, however, provided values too low for diagnosis. In conclusion, ELISA D-dimer assay is a non-sensitive, non-specific test for coronary artery disease as defined by coronary catheterization. However, the assay adds information regarding the severity of disease in patients presenting with acute coronary syndrome.

Insights from apoB: from better diagnosis & therapy to the Medusa Hypothesis

This article will review six of the most important insights that have come from the measurement of apolipoprotein B (apoB). Amongst these are critical clinical advances, which include better definition of those at high risk of vascular disease and better definition of the adequacy of statin therapy. There are also major advances in our understanding of the fundamental processes that interact to cause vascular disease. These include a more precise understanding of the determinants of lipoprotein levels and lipoprotein composition in plasma and, even more importantly, an appreciation of the pivotal role excess fatty acid intake and impaired fatty acid trapping by adipose tissue play in the generation of the complex risk profile that is so common in patients with coronary disease. We have designated the constellation of hypertriglyceridemic (hyperTg) hyperapoB, dysglycemia, and elevated levels of markers of prothrombosis and inflammation--all of which are traceable to adipose tissue dysfunction--as the Medusa Hypothesis. The Medusa Hypothesis puts forward a common pathophysiology for the complex and biologically diverse array of factors that have been associated with vascular disease.

Effects of lipids and lipid-lowering therapy on hemostatic factors in patients with myocardial infarction

BACKGROUND

The risk of cardiovascular disease (CVD) is associated with specific hemostatic markers and lipid profiles, and evidence indicates that there are associations between lipid profiles and the levels of certain hemostatic factors. The disturbances in hemostasis and the risk of CVD can be ameliorated by lipid-lowering therapy.

OBJECTIVE

We investigated the associations of lipid profiles with factor (F)VIIa, von Willebrand factor (VWF), D-dimer and plasminogen activator inhibitor-1 (PAI-1), and examined whether lipid-lowering statin therapy would affect the levels of these hemostatic markers.

PATIENTS AND METHODS

This cross-sectional study analyzed 1045 postmyocardial infarction patients.

RESULTS

In multivariate regression analyses (without adjusting for clinical covariates) HDL-cholesterol (HDL-C) and HDL size were independent and significant predictors of FVIIa; HDL size was a predictor of VWF; HDL size, HDL-C and LDL size were predictors of D-dimer; and triglyceride and HDL size were predictors of PAI-1. After adjusting for clinical covariates, HDL-C, lipoprotein (Lp)(a), apolipoprotein B (apoB) and warfarin were independent and significant predictors of FVIIa; HDL size, age, diabetes mellitus, insulin, race and warfarin were predictors of VWF; HDL-C, HDL size, LDL size, age, warfarin, hypertension and gender were predictors of D-dimer; and triglyceride, HDL size, body mass index, insulin and hypertension were predictors of PAI-1. Patients on statin therapy had significantly lower levels of D-dimer than those who were not on this therapy.

CONCLUSION

There are significant associations of lipid profiles with hemostatic factors, the directions of which suggest novel pathways by which dyslipidemia may contribute to coronary heart disease.

Risk stratification and management of sudden cardiac death: a new paradigm

Risk Stratification and Management of SCD. Management of SCD is undergoing radical change in direction. It is becoming increasingly appreciated that besides depressed left ventricular systolic function and the conventional risk stratification tools, new markers for plaque vulnerability, enhanced thrombogenesis, specific genetic alterations of the autonomic nervous system, cardiac sarcolemmal and contractile proteins, and familial clustering may better segregate patients with atherosclerotic coronary artery disease who are at high risk for SCD from those who may suffer from nonfatal ischemic events. Better understanding of pathophysiologic processes, such as postmyocardial infarction remodeling, the transition from compensated hypertrophy to heart failure, and the increased cardiovascular risk of coronary artery disease in the presence of diabetes or even a prediabetic state will help to improve both risk stratification and management. The rapidly developing fields of microchips technology and proteomics may allow rapid and cost-effective mass screening of multiple risk factors for SCD. The ultimate goal is to identify novel methods for risk stratification, risk modification, and prevention of SCD that could be applied to the general public at large.

Apolipoprotein B and apolipoprotein A-I: risk indicators of coronary heart disease and targets for lipid-modifying therapy

Although LDL cholesterol (LDL-C) is associated with an increased risk of coronary heart disease, other lipoproteins and their constituents, apolipoproteins, may play an important role in atherosclerosis. Elevated levels of apolipoprotein (apo) B, a constituent of atherogenic lipoproteins, and reduced levels of apo A-I, a component of anti-atherogenic HDL, are associated with increased cardiac events. Apo B, apo A-I and the apo B/apo A-I ratio have been reported as better predictors of cardiovascular events than LDL-C and they even retain their predictive power in patients receiving lipid-modifying therapy. Measurement of these apolipoproteins could improve cardiovascular risk prediction.

The apoB/apoA-I ratio is better than the cholesterol ratios to estimate the balance between plasma proatherogenic and antiatherogenic lipoproteins and to predict coronary risk

Background: The apolipoprotein B (apoB)/apoA-I ratio represents the balance of proatherogenic and antiatherogenic lipoproteins. The purpose of this study was to determine whether the apoB/apoA-I ratio was superior to any of the cholesterol ratios – total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C), low-density lipoprotein cholesterol (LDL-C)/HDL-C and non-HDL-C/HDL-C – in predicting the risk of coronary disease. Moreover, we examined whether any lipids, lipoproteins or cholesterol ratios add significant predictive information beyond that provided by the apoB/apoA-I ratio.

Methods: Plasma lipids, lipoproteins, apoB, and apoA-I were measured in 69,030 men and 57,168 women above 40years of age. After a mean follow-up of 98months, 1183 men and 560 women had died from a myocardial infarction in this prospective apolipoprotein-related mortality risk (AMORIS) study.

Results: High apoB and a high apoB/apoA-I ratio were strongly related to increased coronary risk, while high apoA-I was inversely related to risk. The apoB/apoA-I ratio was superior to any of the cholesterol ratios in predicting risk. This advantage was most pronounced in subjects with LDL-C levels <3.6mmol/l. Addition of lipids, lipoproteins or any cholesterol ratio to apoB/apoA-I in risk models did not further improve the strong predictive value of apoB/apoA-I.

Conclusions: These results indicate that the apoB/apoA-I ratio is at present the best single lipoprotein-related variable to quantitate coronary risk. Given the additional advantages apolipoproteins possess – fasting samples are not required, apoB/apoA-I is a better index of the adequacy of statin therapy than LDL-C, and the measurement of apoB and apoA-I are standardized, whereas LDL-C and HDL-C are not – there would appear to be considerable advantage to integrating apolipoproteins into clinical practice.

Role of fibrin D-dimer testing in emergency medicine

OBJECTIVES

Systemic values of the fibrinolytic plasma marker fibrin D-dimer are raised in a variety of acute clinical conditions. D-dimer values can now be rapidly determined and used to aid diagnosis in emergency medicine. However, despite clinical guidelines, inappropriate and unnecessary measurement of D-dimer values is a significant clinical problem. An understanding of the pathophysiological basis and limitations of the value of D-dimer values may help reduce this problem. This review discusses the pathophysiology of the fibrinolytic system. The currently used assays, clinical indications, and limitations of D-dimer measurement are reviewed. Finally, the potential future clinical indications for measurement of D-dimer values in emergency medicine are discussed.

METHODS

Literature on D-dimer was identified from Medline, along with cross referencing from the reference lists of major articles on the subject

RESULTS

and conclusions: Systemic D-dimer values aids diagnosis, and is potentially a prognostic indicator, in a variety of clinical conditions in emergency medicine. However, it has limited specificity in patients with comorbid conditions. Although, currently, there is no standard D-dimer assay, immunoturbidimetric assays are the most suitable for use in emergency medicine

Prediction of Recurrent Events by D-Dimer and Inflammatory Markers in Patients with Normal Cardiac Troponin I (PREDICT) Study

BACKGROUND

The independent predictive value of d-dimer and inflammatory markers for the risk of recurrent adverse events in patients with acute chest pain but normal levels of cardiac troponin I (cTnI) remains unclear.

METHODS

We studied 391 patients admitted to the hospital in 1 year with acute ischemic-type chest pain. Creatine kinase-myocardial band isoenzyme (CK-MB) mass and cTnI levels were measured in initial and 12-hour samples. Soluble intercellular adhesion molecule (sICAM)-1, vascular cell adhesion molecule (sVCAM)-1, sP-selectin, sE-selectin, high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL6), fibrinogen, and d-dimer levels were measured in initial samples. A 1-year incidence of death, myocardial infarction (MI), revascularization, or readmission with chest pain was determined (with death/MI as the primary end point).

RESULTS

Patients with normal levels of CK-MB(mass) and cTnI (195/391[50%]) were at a lower risk than patients with elevated levels of CK-MB(mass) or cTnI, but still had an important incidence of events (77/195[39%]). Marker elevation was defined as >75th percentile (upper quartile). Elevated d-dimer levels (>580 ng/mL) was predictive of death/MI (odds ratio, 5.4; 95% CI, 1.5-20.2; P =.005). Elevated sP-selectin levels (>152 ng/mL; odds ratio, 3.2; 95% CI, 0.9-11.6; P =.06) trended to increased death/MI rates, with weaker trends for elevated levels of hsCRP (>7.1 mg/L), IL6 (>10.7 pg/mL), and ST depression. Other markers, other electrocardiogram changes, or classic risk factors were not predictive of death/MI. With a multivariate analysis, d-dimer and sP-selectin were found to be of independent significance for death/MI after adjustment for inflammatory, hemostatic, and electrocardiogram markers and d-dimer after adjustment for classic risk factors.

CONCLUSION

Normal cTnI levels after acute chest pain does not confer absence of future risk. Concurrent assessment of d-dimer and inflammatory markers may improve risk stratification.

HMG CoA reductase inhibitor suppresses the expression of tissue factor and plasminogen activator inhibitor-1 induced by angiotensin II in cultured rat aortic endothelial cells

BACKGROUND

It has been demonstrated that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (HRIs) reduce the incidence of acute cardiovascular events in patients with hyperlipidemia. Recent reports have shown that the protective effects of these drugs against cardiovascular events are also observed in patients without hyperlipidemia, but the mechanism of this favorable effect still remains unclear. In this study, the effects of HRIs on the endothelial regulation of thrombus formation were elucidated.

METHODS AND RESULTS

The mRNA and protein expression of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) induced by angiotensin II (Ang II) were evaluated in cultured rat aortic endothelial cells. Pretreatment with simvastatin (0.03-3 microg/ml) significantly inhibited TF and PAI-1 induction by Ang II in a dose- and time-dependent manner. These inhibitions were significantly attenuated by mevalonic acid or geranylgeranyl pyrophosphate. Both Rho inhibitor, C3 exoenzyme, and Rho kinase inhibitor, Y-27632, mimicked the inhibitory effects of simvastatin against TF and PAI-1 induced by Ang II. This result suggested that the Rho/Rho kinase pathway is related to the TF and PAI-1 induction by Ang II.

CONCLUSION

It was indicated that simvastatin maintains endothelial cells to be antithrombotic by inhibiting TF and PAI-1 expression via the Rho/Rho kinase pathways in which AngII induces TF and PAI-1 expression. These observations explain, at least partly, the mechanism of the favorable effects of simvastatin in reducing the thrombotic events.

Effects of lipids on thrombotic mechanisms in atherosclerosis

Cholesterol lowering therapy markedly reduces the frequency of subsequent cardiovascular events and is associated with a modest degree of angiographic regression of atherosclerotic lesions. There is a strong association between lipids and fibrinogen, plasminogen activator-1, and activated factor VII levels. Low density lipoprotein may be thrombogenic whereas high density lipoprotein protects against thrombosis. Lipoprotein (a) may affect atherosclerosis and thrombosis mainly by binding to fibrin and attenuating the fibrin-enhanced plasminogen activation. Tissue factor-complex initiates coagulation by activating factor X and factor IX leading in the presence of calcium to the generation of thrombin. Lipid lowering treatment with statins stabilizes atheromatous plaque and has antithrombotic effects. Therefore there are links between lipids and the haemostatic mechanisms which affect atherosclerotic, vasomotor and thrombotic components of ischemic heart disease.