Benefits of lipid lowering on vascular reactivity in patients with coronary artery disease and average cholesterol levels: a mechanism for reducing clinical events?

Long-Lasting Control of LDL Cholesterol Induces a 40% Reduction in the Incidence of Cardiovascular Events: New Insights from a 7-Year Study

Recent studies have yielded controversial results on the long-term effects of statins on the risk of cardiovascular (CV) events. To fill this knowledge gap, we assessed the relationship between low-density lipoprotein cholesterol (LDL-C) levels and CV events in hypertensive patients without previous CV events and naïve to antidyslipidemic treatment within the "Campania Salute Network" in Southern Italy. We studied 725 hypertensive patients with a mean follow-up of 85.4 ± 25.7 months. We stratified our cohort into three groups based on LDL cholesterol (LDL-C) levels in mg/dl: group 1) patients showing during the follow-up a mean LDL-C value ≤100 mg/dl in absence of statin therapy; group 2) statin-treated patients with LDL ≤100 mg/dl; and group 3) patients with LDL-C >100 mg/dl. No significant difference among the groups was observed in terms of demographic and clinical characteristics and medications. The incidence of first CV events was 5.7% in group 1, 6.0% in group 2, and 11.9% in group 3 (P < 0.05 vs. group 1 and group 2). A stable long-term satisfactory control of LDL-C plasma concentration (≤100 mg/dl) reduced the incidence of major CV events from one event every 58.6 patients per year to one event every 115.9 patients per year. These findings were confirmed in a Cox regression analysis, adjusting for potential confounding factors. Collectively, our data demonstrate that a 7-year stable control of LDL-C reduces the incidence of CV events by 40%. SIGNIFICANCE STATEMENT: There are several discrepancies between Mendelian studies and other investigations concerning the actual effects of reduction of plasma concentration of low-density lipoprotein (LDL) cholesterol on the incidence of major cardiovascular events. Taken together, our data in nondiabetic subjects show that a 7-year stable control of LDL cholesterol induces a ∼40% reduction of the incidence of cardiovascular events.

Effect of magnesium supplementation on endothelial function: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Findings of past studies are inconsistent regarding the effects of magnesium (Mg) supplementation on endothelial function (EF). We performed this meta-analysis to examine the effects of magnesium supplementation on flow-mediated dilation (FMD) and carotid intima media thickness (CIMT) as markers of EF.

METHODS

Literature searches of English publications in MEDLINE and EMBASE databases were conducted up to November 2017. Results are reported as weighted mean difference (MD) with 95% confidence intervals (CI) using random effects model (DerSimonian-Laird method). Cochrane's Q test and I-squared (I²) were used to determine heterogeneity among included studies. To determine potential sources of heterogeneity, subgroup analysis was conducted for pre-defined criteria. Funnel plot and Egger's regression test were used to assess publication bias.

RESULTS

Seven RCTs with 306 participants were included. Mg supplementation significantly increased FMD (MD: 2.97; 95% CI: 0.23 to 5.70%, p = 0.033). Between studies heterogeneity was high and subgroup analysis could not identify the sources of heterogeneity. Magnesium supplementation had no significant effect on CIMT (MD: -0.13 mm; 95% CI: 0.27, 0.01; p = 0.077) with high heterogeneity. Mg dose, duration of treatment, healthy status, baseline CIMT and sample size were the potential sources of heterogeneity. Mg supplementation could decrease CIMT to a greater extent in hemodialysis (HD) patients; lower doses of Mg, higher sample size and follow up duration and subjects with higher baseline CIMT also reduced the heterogeneity to some degree (p < 0.001).

CONCLUSIONS

Magnesium supplementation may improve endothelial function without affecting carotid intima media thickness.

Improved endothelial function after short-term therapy with evolocumab

BACKGROUND

The reduction of cholesterol levels with cholesterol-lowering therapy may improve endothelial function. Lipid-lowering therapy has been greatly enhanced by the introduction of proprotein convertase subtilisin/kexin type 9 (PCSK9) antibodies. Less is known of the effect of PCSK9 inhibitors on endothelial function of subjects with hypercholesterolemia.

OBJECTIVE

To assess whether treatment with PCSK9 inhibitors may improve endothelial function evaluated by brachial artery vasoreactivity test.

METHODS

Brachial artery vasoreactivity test was performed in 14 consecutive patients with previous myocardial infarction before and after 2 months of therapy with evolocumab 140 mg twice in a month. Mean brachial artery diameter, velocity time integral, flow-mediated dilation (FMD) and low-density lipoprotein (LDL) cholesterol levels were also evaluated.

RESULTS

After 2 months of treatment with evolocumab, mean total cholesterol levels decreased from 245 ± 41 to 128 ± 30 mg/dL (P < .001, -48%), and LDL levels from 176 ± 43 to 71 ± 26 mg/dL (P = .001, -59%); FMD conversely increased from 6.3 ± 4.1% to 8.8 ± 6.3% (P = .004, +40%). Improvement in FMD was proportional to reduction of LDL levels (r = 0.69, P = .006). Therapy with evolocumab increased brachial artery diameter during vasoreactivity test (peak values 0.39 ± 0.09 vs 0.36 ± 0.11 cm, P = .010; final values 0.36 ± 0.10 vs 0.34 ± 0.10 cm, P = .001), and velocity time integral (peak levels 96 ± 1 vs 85 ± 9 cm, P = .045).

CONCLUSIONS

Two months of treatment with evolocumab 140 mg may improve endothelial function in subjects with increased cardiovascular risk. The improvement in endothelial function is proportional to LDL reduction.

American Society of Echocardiography Report

Noninvasive measures of atherosclerosis have emerged as adjuncts to standard cardiovascular disease (CVD) risk factors in an attempt to refine risk stratification and the need for more aggressive preventive strategies. Two such approaches, carotid artery imaging and brachial artery reactivity testing (BART), are ultrasound based. Numerous carotid artery imaging protocols have been used, and methodologic aspects are described in detail in this review. The panel recommends that protocols: (1) use end-diastolic (minimum dimension) images for intimal-medial thickness (IMT) measurements; (2) provide separate categorization of plaque presence and IMT; (3) avoid use of a single upper limit of normal for IMT because the measure varies with age, sex, and race; and (4) incorporate lumen measurement, particularly when serial measurements are performed to account for changes in distending pressure. Protocols may vary in the number of segments wherein IMT is measured, whether near wall is measured in addition to far wall, and whether IMT measurements are derived from B-mode or M-mode images, depending on the application. BART is a technique that requires meticulous attention to patient preparation and methodologic detail. Its application is substantially more challenging than is carotid imaging and remains largely a research technique that is not readily translated into routine clinical practice.

Effects of orlistat plus diet on postprandial lipemia and brachial artery reactivity in normolipidemic, obese women with normal glucose tolerance: A prospective, randomized, controlled Study

BACKGROUND

Postprandial lipemia (PPL) is an independent predictor of earlyatherosclerosis and coronary artery disease. It is defined as a postprandial triglyceride (TG) level ≥80% higher than the fasting level. Brachial arterial reactivity (BAR) is used to identify early-phase atherosclerosis. Data concerning whether orlistat improves PPL and endothelial function are lacking.

OBJECTIVE

The aim of this study was to determine the effects of orlistat on PPL and BAR in normolipidemic, obese women with normal glucose tolerance.

METHODS

This prospective, randomized, controlled study was conducted at Baskent University, Ankara, Turkey. Normolipidemic, obese women aged 18 to 65 years with normal glucose tolerance were eligible for screening. On screening, demographic information, anthropomorphic parameters (body mass index [BMI], waist circumference [WC], hip circumference, waist-hip ratio), BAR, laboratory test results (level of insulin resistance assessed using the homeostasis model assessment-insulin resistance [HOMA-IR] index, serum lipid profile, fasting plasma levels of glucose and insulin [FPI]), and oral fat-loading test results were recorded as baseline values. The primary end points were the effects of orlistat + diet on PPL (assessed using the AUC of TG) and BAR. Women found on screening to be PPL positive were randomly assigned in a 2:1 ratio to treatment with orlistat 120 mg TID plus low-calorie diet (600-kcal/d deficit; minimum, 1200 kcal/d) or low-calorie diet only (control) for 12 weeks. After 12 weeks, all of the above assessments were repeated, and AUC values for lipid parameters were calculated as secondary outcome measures. To assess tolerability and compliance, women were monitored by telephone each week and instructed to return every 4 weeks for clinic visits.

RESULTS

Twenty-seven women were identified as PPL positive and assigned to the orlistat + diet group (18 subjects) or the control group (9) (mean [SD] age, 45.9 [2.3] years; mean [SD] weight, 87.4 [2.5] kg; mean [SD] BMI, 36.0 [0.8] kg/m(2)). Treatment with orlistat + diet was associated with significantly greater changes from baseline compared with controls in WC (P= 0.003), fasting and postprandial serum TG levels (P = 0.012 and P < 0.001, respectively), FPI level (P = 0.001), and HOMA-IR index (P < 0.001). Logistic regression analysis found that 12 weeks of treatment with orlistat + diet was associated with a numeric, but statistically non-significant, 4.1-fold change in PPL, which was independent of reductions from baseline in weight and WC. Neither treatment was associated with significant changes from baseline in BAR. The prevalences of gastrointestinal symptoms previously found to be related to orlistat use were statistically similar between the orlistat + diet and control groups (9 [50.0%] vs 3 [33.3%] subjects).

CONCLUSIONS

The results of this small study in normolipidemic, obesewomen with normal glucose tolerance suggest that 12 weeks of treatment with orlistat 120 mg/d plus low-calorie diet was associated with a numeric, but statistically nonsignificant, 4.1-fold change from baseline in PPL, which was independent of reductions from baseline in weight and WC. Treatment with orlistat + diet was associated with significant effects on WC, TG, and level of insulin resistance, but not BAR.

The Heart and Medicine: Exploring the Interconnectedness of Cardiometabolic-related Concerns Through a Systems Biology Approach

Patients do not just wake up one morning with cardiac disease. Instead there is an extended preclinical phase during which lifestyle choices determine outcome. Recent advances in our understanding of oxidative stress, endocrine signaling, immune/inflammatory balance, and energy production illuminate opportunities for efficacious intervention. A thorough exploration of these pathophysiologies will allow physicians the opportunity to offer their patients a journey away from illness and disease to optimal wellness.

Exposure to isoflavone-containing soy products and endothelial function: a Bayesian meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

To determine whether and to what degree exposure to isoflavone-containing soy products affects EF. Endothelial dysfunction has been identified as an independent coronary heart disease risk factor and a strong predictor of long-term cardiovascular morbidity and mortality. Data on the effects of exposure to isoflavone-containing soy products on EF are conflicting.

METHODS AND RESULTS

A comprehensive literature search was conducted using the PUBMED database (National Library of Medicine, Bethesda, MD) inclusively through August 21, 2009 on RCTs using the keywords: soy, isoflavone, phytoestrogen, EF, flow mediated vasodilation, and FMD. A Bayesian meta-analysis was conducted to provide a comprehensive account of the effect of isoflavone-containing soy products on EF, as measured by FMD. A total of 17 RCTs were selected as having sufficient data for study inclusion. The overall mean absolute change in FMD (95% Bayesian CI) for isoflavone-containing soy product interventions was 1.15% (-0.52, 2.75). When the effects of separate interventions were considered, the treatment effect for isolated isoflavones was 1.98% (0.07, 3.97) compared to 0.72% (-1.39, 2.90) for isoflavone-containing soy protein. The models were not improved when considering study-specific effects such as cuff measurement location, prescribed dietary modification, and impaired baseline FMD.

CONCLUSIONS

Cumulative evidence from the RCTs included in this meta-analysis indicates that exposure to soy isoflavones can modestly, but significantly, improve EF as measured by FMD. Therefore, exposure to isoflavone supplements may beneficially influence vascular health.

Small artery function 2 years postpartum in women with altered glycaemic distributions in their preceding pregnancy

GDM (gestational diabetes mellitus) is associated with later adverse cardiovascular risk. The present study examined the relationship between glycaemia during pregnancy and small artery function and structures approx. 2 years postpartum. Women were originally enrolled in the HAPO (Hyperglycaemia and Adverse Pregnancy Outcome) study from which they were classified by their glycaemic distribution during pregnancy as controls (in the lower half of the distribution), UQ (upper quartile; in the UQ of the glycaemic distribution) or having had overt GDM. Subcutaneous arteries from a gluteal fat biopsy taken at follow-up 2 years later were examined using wire myography. Small artery structure, stiffness and vasoconstrictor responses were similar across groups. Maximal endothelium-dependent dilation in response to carbachol was impaired in arteries from both GDM (43.3%, n=8 and P=0.01) and UQ (51.7%, n=13 and P=0.04) women despite generally 'normal' current glycaemia (controls, 72.7% and n=8). Inhibition of NOS (nitric oxide synthase) significantly reduced maximum endothelium-dependent dilation in controls but had no effect on arteries from UQ and GDM women, suggesting impaired NOS activity in these groups. Endothelium-independent dilation was unaffected in arteries from previous GDM and UQ women when compared with the control group. Multiple regression analysis suggested that BMI (body mass index) at biopsy was the most potent factor independently associated with small artery function, with no effect of current glycaemia. Overweight women with either GDM or marginally raised glycaemia during pregnancy (our UQ group) had normal vascular structure and stiffness, but clearly detectable progressively impaired endothelium-dependent function at 2 years follow-up. These results suggest that vascular pathology, which may still be reversible, is detectable very early in women at risk of decline into Type 2 diabetes mellitus.

Improvement in endothelium dysfunction in diabetics treated with statins: a randomized comparison of atorvastatin 20 mg versus rosuvastatin 10 mg

AIM

To investigate the effect a 3-month treatment with atorvastatin 20 mg compared with rosuvastatin 10 mg on endothelium dysfunction in subjects with diabetes.

METHODS

A total of 22 consecutive subjects with diabetes who were not receiving statins were enrolled in the study. Endothelium function was assessed before treatment (T0), after 1 month (T1), and after 3 months of treatment (T2) with statins with brachial echo-Doppler test. Patients were randomized to receive atorvastatin 20 mg or rosuvastatin 10 mg. Blood samples were drawn in the meantime in order to evaluate C-reactive protein (CRP) plasmatic concentrations.

RESULTS

A total of 82% of patients enrolled showed endothelium dysfunction (hyperemic reserve <5%). Treatment with statins significantly improved endothelium function in diabetics. Subjects with endothelium dysfunction decreased from 82% (T0) to 44% (T2): mean hyperemic reserve values increased from 2.64% (T0) to 3.23% (T1) and 4% (T2) in patients treated with rosuvastatin (ANOVA P < 0.01), and from 2.74% (T0) to 2.75% (T1) and 4.40% (T2) in those treated with atorvastatin (ANOVA P < 0.01); differences were significant only comparing T2 with T0. Relative increase in endothelium reserve was 51.51% with rosuvastatin versus 60.58% with atorvastatin (P N.S.). Both statins significantly reduced plasmatic levels of CRP (3.18 +/- 2.43 mg/dL [T0] vs. 1.31 +/- 1.67 mg/dL [T2] with rosuvastatin [P < 0.01], 7.53 +/- 7.46 mg/dL [T0] vs. 2.92 +/- 2.06 mg/dL [T2] with atorvastatin [P < 0.01]). Relative reduction of CRP levels was -50.57% with rosuvastatin versus -36.28% with atorvastatin (P N.S.).

CONCLUSION

A 3-month treatment with either atorvastatin 20 mg or rosuvastatin 10 mg is effective in improving endothelium dysfunction in subjects with diabetes.

Rational approach to the treatment for heterozygous familial hypercholesterolemia in childhood and adolescence: a review

Atherosclerosis represents a disease that begins in childhood and in which LDL cholesterol plays a pivotal role for the development of the pathology. Children and adolescents with high cholesterol levels are more likely than their peers to present cholesterol elevation as adults. The identification of genetic dyslipidemias associated with premature cardiovascular disease is crucial during childhood to delay or prevent the atherosclerotic process. Guidelines for the diagnosis and treatment of hypercholesterolemia during pediatric age are available from the National Cholesterol Education Program. A heart-healthy diet should begin at the age of 2 yr and a large number of studies have demonstrated no adverse effects on nutritional status, growth, pubertal development, and psychological aspects in children and adolescents limiting total and saturated fat intake. Pharmacotherapy should be considered in children over 10 yr of age when LDL cholesterol concentrations remain very high despite severe dietary therapy, especially when multiple risk factors are present. The only lipid-lowering drugs recommended up to now for childhood and adolescence are resins reported to be effective and well tolerated, although compliance is very poor because of unpalatability. The use of statins is increasing and seems to be effective and safe in children, even if studies enrolled a small number of patients and evaluated efficacy and safety for short-term periods. Recently, an interesting drug represented by ezetimibe has been found that may provide cholesterol-lowering additive to that reached with statin treatment. This review provides an update on recent advances in the diagnosis, therapy, and follow-up of familial hypercholesterolemia during pediatric age and adolescence.

Endothelial dysfunction: a comprehensive appraisal

The endothelium is a thin monocelular layer that covers all the inner surface of the blood vessels, separating the circulating blood from the tissues. It is not an inactive organ, quite the opposite. It works as a receptor-efector organ and responds to each physical or chemical stimulus with the release of the correct substance with which it may maintain vasomotor balance and vascular-tissue homeostasis. It has the property of producing, independently, both agonistic and antagonistic substances that help to keep homeostasis and its function is not only autocrine, but also paracrine and endocrine. In this way it modulates the vascular smooth muscle cells producing relaxation or contraction, and therefore vasodilatation or vasoconstriction. The endothelium regulating homeostasis by controlling the production of prothrombotic and antithrombotic components, and fibrynolitics and antifibrynolitics. Also intervenes in cell proliferation and migration, in leukocyte adhesion and activation and in immunological and inflammatory processes. Cardiovascular risk factors cause oxidative stress that alters the endothelial cells capacity and leads to the so called endothelial "dysfunction" reducing its capacity to maintain homeostasis and leads to the development of pathological inflammatory processes and vascular disease.

There are different techniques to evaluate the endothelium functional capacity, that depend on the amount of NO produced and the vasodilatation effect. The percentage of vasodilatation with respect to the basal value represents the endothelial functional capacity. Taking into account that shear stress is one of the most important stimulants for the synthesis and release of NO, the non-invasive technique most often used is the transient flow-modulate "endothelium-dependent" post-ischemic vasodilatation, performed on conductance arteries such as the brachial, radial or femoral arteries. This vasodilatation is compared with the vasodilatation produced by drugs that are NO donors, such as nitroglycerine, called "endothelium independent". The vasodilatation is quantified by measuring the arterial diameter with high resolution ultrasonography. Laser-Doppler techniques are now starting to be used that also consider tissue perfusion.

There is so much proof about endothelial dysfunction that it is reasonable to believe that there is diagnostic and prognostic value in its evaluation for the late outcome. There is no doubt that endothelial dysfunction contributes to the initiation and progression of atherosclerotic disease and could be considered an independent vascular risk factor. Although prolonged randomized clinical trials are needed for unequivocal evidence, the data already obtained allows the methods of evaluation of endothelial dysfunction to be considered useful in clinical practice and have overcome the experimental step, being non-invasive increases its value making it use full for follow-up of the progression of the disease and the effects of different treatments.

Endothelial Function in Healthy 11-Year-Old Children After Dietary Intervention With Onset in Infancy

Background— Early childhood introduction of nutritional habits aimed at atherosclerosis prevention reduces children’s serum total cholesterol concentration, but its effect on vascular endothelial function is unknown.

Methods and Results— Between 1990 and 1992, we randomized healthy 7-month-old infants (n=1062) to intervention (low-saturated-fat diet) and control (unrestricted diet) groups. At the age of 11 years, endothelium-dependent (flow-mediated) and endothelium-independent (nitrate-mediated) vasodilatory responses of the brachial artery were measured with high-resolution ultrasound in 179 intervention and 190 control children. The effect of intervention on endothelial function was significant in boys ( P =0.0034) but not in girls ( P =0.69). The maximum endothelium-dependent dilation response (mean±SD) was 9.62±3.53% and 8.36±3.85% in intervention boys and control boys and 8.84±4.00% and 8.44±3.60% in intervention girls and control girls, respectively. Intervention had no effect on nitrate-mediated dilation. The difference in endothelial function in boys remained significant after adjustment for current serum total or LDL cholesterol but became nonsignificant after adjustment for mean cholesterol measured under 3 years of age (adjusted means: 9.46% [CI 8.68% to 10.24%] versus 8.54% [CI 7.75% to 9.32%], P =0.11).

Conclusions— A low-saturated-fat diet introduced in infancy and maintained during the first decade of life is associated with enhanced endothelial function in boys. The effect is explained in part by the diet-induced reduction in serum cholesterol concentration.

A randomized trial of aggressive lipid reduction for improvement of myocardial ischemia, symptom status, and vascular function in patients with coronary artery disease not amenable to intervention

PURPOSE

To determine the effects of aggressive lipid lowering on markers of ischemia, resistance vessel function, atherosclerotic burden, and symptom status in patients with symptomatic coronary artery disease.

METHODS

Sixty consecutive patients with coronary artery disease that was unsuitable for revascularization were assigned randomly to either usual therapy of lipids for patients with a low-density lipoprotein (LDL) cholesterol target level <116 mg/dL, or to a more aggressive lipid-lowering strategy involving up to 80 mg/d of atorvastatin, with a target LDL cholesterol level <77 mg/dL. The extent and severity of inducible ischemia (by dobutamine echocardiography), vascular function (brachial artery reactivity), atheroma burden (carotid intima-media thickness), and symptom status were evaluated blindly at baseline and after 12 weeks of treatment.

RESULTS

After 12 weeks of treatment, patients in the aggressive therapy group had a significantly greater decrease in mean (+/- SD) LDL cholesterol level than those in the usual care group (29 +/- 38 mg/dL vs. 7 +/- 24 mg/dL, P = 0.03). Patients in the aggressive therapy group had a reduction in the number of ischemic wall segments (mean between-group difference of 1.3; 95% confidence interval: 0.1 to 2.0; P = 0.04), flow-mediated dilatation (mean between-group difference of 5.9%; 95% confidence interval: 2.5% to 9.4%; P = 0.001), and angina score after 12 weeks. There were no significant changes in atherosclerotic burden in either group.

CONCLUSION

Patients with symptomatic coronary artery disease who are treated with aggressive lipid lowering have improvement of symptom status and ischemia that appears to reflect improved vascular function but not atheroma burden.

Long-term treatment effect of atorvastatin on aortic stiffness in hypercholesterolaemic patients

AIM

To assess the effect of atorvastatin on aortic stiffness in hypercholesterolaemic patients free of arterial hypertension and diabetes mellitus.

METHODS AND RESULTS

The study included 36 patients (25 men and 11 women, mean age 56 +/- 12 years); 18 patients had stable coronary heart disease (CHD) and 18 were free of CHD at baseline. All patients received atorvastatin (20 mg/day) for a 2-year period. Aortic stiffness was assessed by transthoracic echocardiography at baseline and 2 years later. At baseline, total cholesterol, low density lipoprotein cholesterol (LDL-C) and LDL-C/high density lipoprotein cholesterol (HDL-C) ratio were positively related to aortic stiffness (p < 0.001 for all). The mean change in lipid parameters during treatment was: total cholesterol -38%, LDL-C -46%, triglycerides -29%, and HDL-C +6%, all significant (p = 0.029 to < 0.0001). After the 2-year treatment with atorvastatin, aortic stiffness was significantly reduced by 14% (p = 0.019). An improvement of left ventricular (LV) ejection fraction by 13% (p < 0.001) and a reduction of LV mass index by 9% (p = 0.008) were also recorded. The change in aortic stiffness was similar in patients with or without CHD.

CONCLUSION

Long-term treatment with atorvastatin improves aortic stiffness; this index is related to total and coronary mortality. Moreover, assessment of aortic stiffness may be useful in identifying which hypercholesterolaemic patients should be treated aggressively, regardless of CHD. The aortic stiffness effect may eventually become an index of the efficacy of lipid lowering treatment.

Endothelial function. From vascular biology to clinical applications

The endothelium, by releasing nitric oxide (NO), promotes vasodilation and inhibits inflammation, thrombosis, and vascular smooth muscle cell proliferation. These biological actions of NO make it an important component in the endogenous defense against atherosclerosis and its overt clinical complications. Loss of the functional integrity of the endothelium, as seen commonly in the milieu of cardiovascular risk factors, plays an integral role in all stages of atherosclerosis from lesion initiation to plaque rupture. A number of established techniques can assess endothelial function in human vascular beds. The outcome of endothelial testing has profound prognostic implications and is an independent predictor of atherosclerosis disease progression and cardiovascular event rates. The large clinical benefit of statins and angiotensin-converting enzyme inhibitors in patients with atherosclerosis involves favorable effects of endothelial function. Studies of endothelial function represent a prime example of a successful application of insights derived from vascular biology at the bedside.

Differential effects of gemfibrozil on migration, proliferation and proteoglycan production in human vascular smooth muscle cells

The aim of this study was to determine, if gemfibrozil has anti-atherogenic actions on human vascular smooth muscle cells (SMCs) and whether these actions are affected by high glucose concentrations, which mimic the hyperglycemia of diabetes. Proliferation of SMCs treated with gemfibrozil was estimated by cell counting (Coulter Counter) and [3H]thymidine incorporation, migration in a scrape-wound assay, proteoglycan (PG) biosynthesis and glycosaminoglycan (GAG) synthesis on xyloside by [35S]sulfate labeling and sizing by sodium dodecyl sulphide-polyacrylamide gel electrophoresis (SDS-PAGE). Gemfibrozil (100 micromol/l) did not affect migration in low or high glucose media. Gemfibrozil caused concentration-dependent inhibition of proliferation in low glucose media (24% inhibition at 100 micromol/l, P<0.01) and inhibited the re-initiation of DNA synthesis by 33.3% (100 micromol/l, P<0.05) in low glucose and 31.4% (100 micromol/l, P<0.001) in high glucose conditions. In low and high glucose media, gemfibrozil (100 micromol/l) reduced total PG production in the presence of TGF-beta 1, which was associated with a decrease in the apparent size of PGs. Gemfibrozil and another PPAR-alpha ligand, WY-14643, significantly inhibited basal and TGF-beta1 stimulated GAG synthesis. We conclude that some SMCs properties associated with atherogenesis are favorably affected by gemfibrozil. Hence, direct vascular actions of gemfibrozil observed in this study may contribute to the reduction in cardiovascular disease observed in clinical studies with gemfibrozil.

Treatment with atorvastatin to the National Cholesterol Educational Program goal versus 'usual' care in secondary coronary heart disease prevention. The GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) study

BACKGROUND

Atorvastatin is very effective in reducing plasma low-density lipoprotein cholesterol (LDL-C) levels. However, there is no long-term survival study that evaluated this statin.

PATIENTS-METHODS

To assess the effect of atorvastatin on morbidity and mortality (total and coronary) of patients with established coronary heart disease (CHD), 1600 consecutive patients were randomised either to atorvastatin or to 'usual' medical care. The dose of atorvastatin was titrated from 10 to 80 mg/day, in order to reach the National Cholesterol Education Program (NCEP) goal of LDL-C <100 mg/dl (2.6 mmol/l). All patients were followed up for a mean period of 3 years.

MAIN OUTCOME MEASURES

Primary endpoints of the study were defined as death, non-fatal myocardial infarction, unstable angina, congestive heart failure, revascularisation (coronary morbidity) and stroke. Secondary endpoints were the safety and efficacy of the hypolipidaemic drugs as well as the cost-effectiveness of atorvastatin.

RESULTS

The mean dosage of atorvastatin was 24 mg/day. This statin reduced total chlesterol by 36%, LDL-C by 46%, triglycerides by 31%, and non-high-density lipoprotein cholesterol (non-HDL-C) by 44%, while it increased HDL-C by 7%; all these changes were significant. The NCEP LDL-C and non-HDL-C treatment goals were reached by 95% (n = 759) and 97% (n = 776), respectively, of patients on atorvastatin. Only 14% of the 'usual' care patients received any hypolipidaemic drugs throughout the study and 3% of them reached the NCEP LDL-C treatment goal. The cost per quaility-adjusted life-year gained with atorvastatin was estimated at $US 8350. During this study 196 (24.5%) CHD patients on 'usual' care had a CHD recurrent event or died vs. 96 (12%) CHD patients on atorvastatin; risk ratio (RR) 0.49, confidence interval (CI) 0.27-0.73, p < 0.0001. In detail, atorvastatin reduced, in comparison to 'usual' care, total mortality (RR 0.57, CI 0.39-0.78, p = 0.0021), coronary mortality (RR 0.53, CI 0.29-0.74, p = 0.0017), coronary morbidity (RR 0.46, CI 0.25-0.71, p < 0.0001), and stroke (RR 0.53, CI 0.30-0.82, p = 0.034). All subgroups of patients (women, those with diabetes mellitus, arterial hypertension, age 60 to 75 years, congestive heart failure, recent unstable angina or prior revascularisation) benefited from treatment with atorvastatin. Withdrawal of patients because of side-effects from the atorvastatin group was low (0.75%) and similar to that of the 'usual' care group (0.4%).

CONCLUSIONS

Long-term treatment of CHD patients with atorvastatin to achieve NCEP lipid targets significantly reduces total and coronary mortality, coronary morbidity and stroke, in comparison to patients receiving 'usual' medical care. Treatment with atorvastatin is well tolerated and cost-effective.

Lipids and endothelium-dependent vasodilation--a review

Studies using both in vitro and in vivo techniques have repeatedly shown that endothelium-dependent vasodilation (EDV) is impaired in different forms of experimental as well as human hypercholesterolemia. Clearly this impaired EDV can be reversed by lowering cholesterol levels by diet or medical therapy. Competitive blocking of L-arginine, changes in nitric oxide synthase activity, increased release of endothelin-1, and inactivation of nitric oxide due to superoxide ions all contribute to the impairment in EDV during dyslipidemia. The oxidation of low density lipoprotein, with its compound lysophosphatidylcholine, plays a critical role in these events. However, data on the role of triglycerides and fat-rich meals regarding EDV are not so consistent as data for cholesterol, although a view that the compositions of individual fatty acids and antioxidants are of major importance is emerging. Thus, this review shows that while impaired EDV is a general feature of hypercholesterolemia, the mechanisms involved and the therapeutic opportunities available still have to be investigated. Furthermore, discrepancies regarding the role of triglycerides and fat content in food may be explained by divergent effects of different fatty acids on the endothelium.

Replacement of dietary saturated fatty acids by trans fatty acids lowers serum HDL cholesterol and impairs endothelial function in healthy men and women

We tested whether trans fatty acids and saturated fatty acids had different effects on flow-mediated vasodilation (FMD), a risk marker of coronary heart disease (CHD). Consumption of trans fatty acids is related to increased risk of CHD, probably through effects on lipoproteins. Trans fatty acids differ from most saturated fatty acids because they decrease serum high-density lipoprotein (HDL) cholesterol, and this may increase the risk of CHD. We fed 29 volunteers 2 controlled diets in a 2x4-week randomized crossover design. The "Trans-diet" contained 9.2 energy percent of trans fatty acids; these were replaced by saturated fatty acids in the "Sat-diet." Mean serum HDL cholesterol after the Trans-diet was 0.39 mmol/L (14.8 mg/dL), or 21% lower than after the Sat-diet (95% CI 0.28 to 0.50 mmol/L). Serum low density lipoprotein and triglyceride concentrations were stable. FMD+SD was 4.4+/-2.3% after the Trans-diet and 6.2+/-3.0% after the Sat-diet (difference -1.8%, 95% CI -3.2 to -0.4). Replacement of dietary saturated fatty acids by trans fatty acids impaired FMD of the brachial artery, which suggests increased risk of CHD. Further studies are needed to test whether the decrease in serum HDL cholesterol caused the impairment of FMD.

Use of electron beam tomography data to develop models for prediction of hard coronary events

BACKGROUND

Prediction of hard cardiac events (myocardial infarction and coronary death) remains difficult in spite of the identification of several relevant risk factors for the development of coronary artery disease (CAD). New indicators of risk might add to our predictive ability. We used measures of coronary artery calcification (CAC) found by electron beam tomography (EBT) imaging to develop prediction models for hard cardiac events alone and in association with traditional risk factors for CAD.

METHODS

Two groups of patients were studied: group A, 676 asymptomatic patients (mean age 52 years, 51% men) prospectively followed up for 32 +/- 7 months after being referred by primary care physicians for a screening EBT, and group B, 10,122 asymptomatic patients screened by EBT at one center and used as controls for calculation of calcium score nomograms.

RESULTS

The occurrence of hard events in group A patients was related to traditional risk factors for CAD, presence of CAC (score >0), Ln (1 + absolute calcium score [CS]), and age- and sex-specific CS percentiles (CS%). Univariate analyses showed that age, smoking, diabetes mellitus, presence of CAC, Ln (1 + absolute CS), and CS% were predictive of hard events (all P <.05). Multiple logistic regression analyses demonstrated that CS% was the only significant predictor of events and provided incremental prognostic value when added to traditional risk factors for CAD (chi-square, P <.001). In a comparison of receiver-operator characteristic curves for prediction of hard events, the area under the curve for CS% plus conventional risk factors and age was significantly larger than that obtained by use of traditional risk factors and age separately as predictors (0.84 vs 0.71, respectively, P <.001). Furthermore, the area under the curve of CS% alone was significantly larger than that of traditional risk factors and age combined (0.82 vs 0.71, P =.028).

CONCLUSIONS

Patients are usually selected for EBT screening on the basis of the presence of conventional risk factors for CAD. However, an age- and sex-specific calcium score provides the best predictive model for the occurrence of hard coronary events and adds incremental prognostic information to conventional risk factors for CAD.