Comparison of ezetimibe plus simvastatin versus simvastatin monotherapy on atherosclerosis progression in familial hypercholesterolemia. Design and rationale of the Ezetimibe and Simvastatin in Hypercholesterolemia Enhances Atherosclerosis Regression (ENHANCE) trial

Advances in targeting LDL cholesterol: PCSK9 inhibitors and beyond

There is a direct relationship between the duration and level of exposure to low density lipoprotein cholesterol (LDL-C) levels over one's lifespan and cardiovascular events. Early treatment to lower elevated LDL-C is crucial for better outcomes with multiple therapies currently available to reduce atherogenic lipoproteins. Statins remain the foundation of LDL-C lowering therapy as one of the most cost-effective drugs to reduce atherosclerotic events (ASCVD) and mortality. Nonetheless, LDL-driven goal attainment remains suboptimal globally, highlighting a considerable need for non-statin therapies to address residual risk related to statin intolerance, non-adherence, and inherited lipoprotein disorders. LDL-C lowering interventions beyond statins include ezetimibe, PCSK9 monoclonal antibodies, inclisiran and bempedoic acid with specific guideline recommendations as to when to consider each. For patients with homozygous familial hypercholesterolemia requiring more advanced therapy, lomitapide and evinacumab are available, providing mechanisms that are not LDL receptor dependent. Lipoprotein apheresis remains an effective option for clinical familial hypercholesterolemia as well as elevated lipoprotein (a). There are investigational therapies being explored to add to our current armamentarium including CETP inhibitors, a third-generation PCSK9 inhibitor (small recombinant fusion protein oral PCSK9 inhibitor) and gene editing which aims to directly restore or disrupt genes of interest at the DNA level. This article is a brief review of the pharmacotherapy options beyond statins for lowering LDL-C and their impact on ASCVD risk reduction. Our primary aim is to guide physicians on the role these therapies play in achieving appropriate LDL-C goals, with an algorithm of when to consider each based on efficacy, safety and outcomes.

Association of Intima-Media Thickness Measured at the Common Carotid Artery With Incident Carotid Plaque: Individual Participant Data Meta-Analysis of 20 Prospective Studies

Background The association between common carotid artery intima-media thickness (CCA-IMT) and incident carotid plaque has not been characterized fully. We therefore aimed to precisely quantify the relationship between CCA-IMT and carotid plaque development. Methods and Results We undertook an individual participant data meta-analysis of 20 prospective studies from the Proof-ATHERO (Prospective Studies of Atherosclerosis) consortium that recorded baseline CCA-IMT and incident carotid plaque involving 21 494 individuals without a history of cardiovascular disease and without preexisting carotid plaque at baseline. Mean baseline age was 56 years (SD, 9 years), 55% were women, and mean baseline CCA-IMT was 0.71 mm (SD, 0.17 mm). Over a median follow-up of 5.9 years (5th-95th percentile, 1.9-19.0 years), 8278 individuals developed first-ever carotid plaque. We combined study-specific odds ratios (ORs) for incident carotid plaque using random-effects meta-analysis. Baseline CCA-IMT was approximately log-linearly associated with the odds of developing carotid plaque. The age-, sex-, and trial arm-adjusted OR for carotid plaque per SD higher baseline CCA-IMT was 1.40 (95% CI, 1.31-1.50; I²=63.9%). The corresponding OR that was further adjusted for ethnicity, smoking, diabetes, body mass index, systolic blood pressure, low- and high-density lipoprotein cholesterol, and lipid-lowering and antihypertensive medication was 1.34 (95% CI, 1.24-1.45; I²=59.4%; 14 studies; 16 297 participants; 6381 incident plaques). We observed no significant effect modification across clinically relevant subgroups. Sensitivity analysis restricted to studies defining plaque as focal thickening yielded a comparable OR (1.38 [95% CI, 1.29-1.47]; I²=57.1%; 14 studies; 17 352 participants; 6991 incident plaques). Conclusions Our large-scale individual participant data meta-analysis demonstrated that CCA-IMT is associated with the long-term risk of developing first-ever carotid plaque, independent of traditional cardiovascular risk factors.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY GUIDELINES FOR MANAGEMENT OF DYSLIPIDEMIA AND PREVENTION OF CARDIOVASCULAR DISEASE

OBJECTIVE

The development of these guidelines is mandated by the American Association of Clinical Endocrinologists (AACE) Board of Directors and American College of Endocrinology (ACE) Board of Trustees and adheres with published AACE protocols for the standardized production of clinical practice guidelines (CPGs).

METHODS

Recommendations are based on diligent reviews of the clinical evidence with transparent incorporation of subjective factors, according to established AACE/ACE guidelines for guidelines protocols.

RESULTS

The Executive Summary of this document contains 87 recommendations of which 45 are Grade A (51.7%), 18 are Grade B (20.7%), 15 are Grade C (17.2%), and 9 (10.3%) are Grade D. These detailed, evidence-based recommendations allow for nuance-based clinical decision-making that addresses multiple aspects of real-world medical care. The evidence base presented in the subsequent Appendix provides relevant supporting information for Executive Summary Recommendations. This update contains 695 citations of which 203 (29.2 %) are EL 1 (strong), 137 (19.7%) are EL 2 (intermediate), 119 (17.1%) are EL 3 (weak), and 236 (34.0%) are EL 4 (no clinical evidence).

CONCLUSION

This CPG is a practical tool that endocrinologists, other health care professionals, health-related organizations, and regulatory bodies can use to reduce the risks and consequences of dyslipidemia. It provides guidance on screening, risk assessment, and treatment recommendations for a range of individuals with various lipid disorders. The recommendations emphasize the importance of treating low-density lipoprotein cholesterol (LDL-C) in some individuals to lower goals than previously endorsed and support the measurement of coronary artery calcium scores and inflammatory markers to help stratify risk. Special consideration is given to individuals with diabetes, familial hypercholesterolemia, women, and youth with dyslipidemia. Both clinical and cost-effectiveness data are provided to support treatment decisions.

ABBREVIATIONS

4S = Scandinavian Simvastatin Survival Study A1C = glycated hemoglobin AACE = American Association of Clinical Endocrinologists AAP = American Academy of Pediatrics ACC = American College of Cardiology ACE = American College of Endocrinology ACS = acute coronary syndrome ADMIT = Arterial Disease Multiple Intervention Trial ADVENT = Assessment of Diabetes Control and Evaluation of the Efficacy of Niaspan Trial AFCAPS/TexCAPS = Air Force/Texas Coronary Atherosclerosis Prevention Study AHA = American Heart Association AHRQ = Agency for Healthcare Research and Quality AIM-HIGH = Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides trial ASCVD = atherosclerotic cardiovascular disease ATP = Adult Treatment Panel apo = apolipoprotein BEL = best evidence level BIP = Bezafibrate Infarction Prevention trial BMI = body mass index CABG = coronary artery bypass graft CAC = coronary artery calcification CARDS = Collaborative Atorvastatin Diabetes Study CDP = Coronary Drug Project trial CI = confidence interval CIMT = carotid intimal media thickness CKD = chronic kidney disease CPG(s) = clinical practice guideline(s) CRP = C-reactive protein CTT = Cholesterol Treatment Trialists CV = cerebrovascular CVA = cerebrovascular accident EL = evidence level FH = familial hypercholesterolemia FIELD = Secondary Endpoints from the Fenofibrate Intervention and Event Lowering in Diabetes trial FOURIER = Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects With Elevated Risk trial HATS = HDL-Atherosclerosis Treatment Study HDL-C = high-density lipoprotein cholesterol HeFH = heterozygous familial hypercholesterolemia HHS = Helsinki Heart Study HIV = human immunodeficiency virus HoFH = homozygous familial hypercholesterolemia HPS = Heart Protection Study HPS2-THRIVE = Treatment of HDL to Reduce the Incidence of Vascular Events trial HR = hazard ratio HRT = hormone replacement therapy hsCRP = high-sensitivity CRP IMPROVE-IT = Improved Reduction of Outcomes: Vytorin Efficacy International Trial IRAS = Insulin Resistance Atherosclerosis Study JUPITER = Justification for the Use of Statins in Primary Prevention: An Intervention Trial Evaluating Rosuvastatin LDL-C = low-density lipoprotein cholesterol Lp-PLA2 = lipoprotein-associated phospholipase A2 MACE = major cardiovascular events MESA = Multi-Ethnic Study of Atherosclerosis MetS = metabolic syndrome MI = myocardial infarction MRFIT = Multiple Risk Factor Intervention Trial NCEP = National Cholesterol Education Program NHLBI = National Heart, Lung, and Blood Institute PCOS = polycystic ovary syndrome PCSK9 = proprotein convertase subtilisin/kexin type 9 Post CABG = Post Coronary Artery Bypass Graft trial PROSPER = Prospective Study of Pravastatin in the Elderly at Risk trial QALY = quality-adjusted life-year ROC = receiver-operator characteristic SOC = standard of care SHARP = Study of Heart and Renal Protection T1DM = type 1 diabetes mellitus T2DM = type 2 diabetes mellitus TG = triglycerides TNT = Treating to New Targets trial VA-HIT = Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial VLDL-C = very low-density lipoprotein cholesterol WHI = Women's Health Initiative.

Ezetimibe for the prevention of cardiovascular disease and all-cause mortality events

BACKGROUND

Cardiovascular disease (CVD) remains an important cause of mortality and morbidity, and high levels of blood cholesterol are thought to be the major modifiable risk factors for CVD. The use of statins is the preferred treatment strategy for the prevention of CVD, but some people at high-risk for CVD are intolerant to statin therapy or unable to achieve their treatment goals with the maximal recommended doses of statin. Ezetimibe is a selective cholesterol absorption inhibitor, whether it has a positive effect on CVD events remains uncertain. Results from clinical studies are inconsistent and a thorough evaluation of its efficacy and safety for the prevention of CVD and mortality is necessary.

OBJECTIVES

To assess the efficacy and safety of ezetimibe for the prevention of CVD and all-cause mortality.

SEARCH METHODS

We searched the CENTRAL, MEDLINE, Embase and Web of Science on 27 June 2018, and two clinical trial registry platforms on 11 July 2018. We checked reference lists from primary studies and review articles for additional studies. No language restrictions were applied.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared ezetimibe versus placebo or ezetimibe plus other lipid-modifying drugs versus other lipid-modifying drugs alone in adults, with or without CVD, and which had a follow-up of at least 12 months.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted data, assessed risk of bias and contacted trialists to obtain missing data. We performed statistical analyses according to the Cochrane Handbook for Systematic Reviews of Interventions and used the GRADE to assess the quality of evidence.

MAIN RESULTS

We included 26 RCTs randomising 23,499 participants. All included studies assessed effects of ezetimibe plus other lipid-modifying drugs compared with other lipid-modifying drugs alone or plus placebo. Our findings were driven by the largest study (IMPROVE-IT), which had weights ranging from 41.5% to 98.4% in the different meta-analyses.Ezetimibe with statins probably reduces the risk of major adverse cardiovascular events compared with statins alone (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.90 to 0.98; a decrease from 284/1000 to 267/1000, 95% CI 256 to 278; 21,727 participants; 10 studies; moderate-quality evidence). Trials reporting all-cause mortality used ezetimibe with statin or fenofibrate and found they have little or no effect on this outcome (RR 0.98, 95% CI 0.91 to 1.05; 21,222 participants; 8 studies; high-quality evidence). Adding ezetimibe to statins probably reduces the risk of non-fatal myocardial infarction (MI) (RR 0.88, 95% CI 0.81 to 0.95; a decrease from 105/1000 to 92/1000, 95% CI 85 to 100; 21,145 participants; 6 studies; moderate-quality evidence) and non-fatal stroke (RR 0.83, 95% CI 0.71 to 0.97; a decrease 32/1000 to 27/1000, 95% CI 23 to 31; 21,205 participants; 6 studies; moderate-quality evidence). Trials reporting cardiovascular mortality added ezetimibe to statin or fenofibrate, probably having little or no effect on this outcome (RR 1.00, 95% CI 0.89 to 1.12; 19457 participants; 6 studies; moderate-quality evidence). The need for coronary revascularisation might be reduced by adding ezetimibe to statin (RR 0.94, 95% CI 0.89 to 0.99; a decrease from 196/1000 to 184/1000, 95% 175 to 194; 21,323 participants; 7 studies); however, no difference in coronary revascularisation rate was observed when a sensitivity analysis was limited to studies with a low risk of bias.In terms of safety, adding ezetimibe to statins may make little or no difference in the risk of hepatopathy (RR 1.14, 95% CI 0.96 to 1.35; 20,687 participants; 4 studies; low-quality evidence). It is uncertain whether ezetimibe increase or decrease the risk of myopathy (RR 1.31, 95% CI 0.72 to 2.38; 20,581 participants; 3 studies; very low-quality evidence) and rhabdomyolysis, given the wide CIs and low event rate. Little or no difference in the risk of cancer, gallbladder-related disease and discontinuation due to adverse events were observed between treatment groups. For serum lipids, adding ezetimibe to statin or fenofibrate might further reduce the low-density lipoprotein cholesterol (LDL-C), total cholesterol and triglyceride levels and likely increase the high-density lipoprotein cholesterol levels; however, substantial heterogeneity was detected in most analyses.None of the included studies reported on health-related quality of life.

AUTHORS' CONCLUSIONS

Moderate- to high-quality evidence suggests that ezetimibe has modest beneficial effects on the risk of CVD endpoints, primarily driven by a reduction in non-fatal MI and non-fatal stroke, but it has little or no effect on clinical fatal endpoints. The cardiovascular benefit of ezetimibe might involve the reduction of LDL-C, total cholesterol and triglycerides. There is insufficient evidence to determine whether ezetimibe increases the risk of adverse events due to the low and very low quality of the evidence. The evidence for beneficial effects was mainly obtained from individuals with established atherosclerotic cardiovascular disease (ASCVD, predominantly with acute coronary syndrome) administered ezetimibe plus statins. However, there is limited evidence regarding the role of ezetimibe in primary prevention and the effects of ezetimibe monotherapy in the prevention of CVD, and these topics thus requires further investigation.

The effect of combined ezetimibe and statin therapy versus statin therapy alone on coronary plaque volume assessed by intravascular ultrasound: A systematic review and meta-analysis

BACKGROUND

Current guidelines recommend an intensive lipid-lowering therapy to achieve the low-density lipoprotein cholesterol (LDL-C) target in patients with high risk of cardiovascular disease. Former studies suggested adding ezetimibe to statin therapy in the above setting may promote plaque changes; however, this effect has not been consistently reported.

METHODS

Electronic searches were performed in MEDLINE, EMBASE, and Cochrane library on November 30, 2017 to identify prospective trials assessing the effects of combined ezetimibe and statin therapy versus statin therapy alone on atheroma volume using intravascular ultrasound. The effect size between treatment groups within individual studies was assessed by weighted mean difference (MD) using a random-effects model.

RESULTS

Eight studies were obtained for systematic review and 6 of them compromising total of 583 subjects that meet the criteria were meta-analyzed. There was a significant reduction from baseline to follow-up in total atheroma volume with an MD of -3.71 mm³ (95% confidence interval: -5.98 to -1.44, P < .001), whereas analysis for percent atheroma volume demonstrated weighted MD of - 0.77% (-1.68 to 0.14, P = .10). A substantial decrease in LDL-C was observed with MD -16.75 mg/dL (-20.89 to -12.60, P < .00001).

CONCLUSION

The addition of ezetimibe to statin therapy is effective in reducing total atheroma volume assessed by intravascular ultrasound and also resulted in effective reduction of plasma LDL-C levels.

The challenges of proprotein convertase subtilisin-kexin-9 inhibitors for lipid guidelines and models of care

PURPOSE OF REVIEW

The article reviews the challenges facing cardiovascular disease (CVD) guidelines committees.

RECENT FINDINGS

Clinical trials in high-risk populations have shown additional CVD event reduction with ezetimibe and proprotein convertase subtilisin-kexin-9 inhibitors. These trials recruit middle-aged secondary prevention populations, whereas increasingly the population at risk of CVD comprises the elderly in primary prevention. Some major guidelines have moved from a lipid-target to a risk-based approach. Some guidelines wish to preserve treatment targets to optimize the risk profile of individual patients as opposed to using population-based approaches. A numbers needed to treat approach has been suggested as a way of prioritizing patients for treatment, while retaining an individual's LDL cholesterol risk. However, the main barrier to implementation of some novel therapies in medicine is not their efficacy or safety but their cost. Health economic approaches that consider both benefits and costs can help guideline committees to define populations mostly likely to benefit.

SUMMARY

The efficacy and expense of novel treatments is challenging traditional guideline development. Previously guideline committees used only to review clinical efficacy and safety endpoints but now they also have to consider costs to derive recommendations that are practical to implement.

Therapeutic Management of Familial Hypercholesterolemia: Current and Emerging Drug Therapies

Familial hypercholesterolemia (FH) is a genetic disorder characterized by significantly elevated low-density lipoprotein cholesterol (LDL-C) concentrations that result from mutations of the LDL receptor, apolipoprotein B (apo B-100), and proprotein convertase subtilisin/kexin type 9 (PCSK9). Early and aggressive treatment can prevent premature atherosclerotic cardiovascular disease in these high-risk patients. Given that the cardiovascular consequences of FH are similar to typical hypercholesterolemia, traditional therapies are utilized to decrease LDL-C levels. Patients with FH should receive statins as first-line treatment; high-potency statins at high doses are often required. Despite the use of statins, additional treatments are often necessary to achieve appropriate LDL-C lowering in this patient population. Novel drug therapies that target the pathophysiologic defects of the condition are continuously emerging. Contemporary therapies including mipomersen (Kynamro, Genzyme), an oligonucleotide inhibitor of apo B-100 synthesis; lomitapide (Juxtapid, Aegerion), a microsomal triglyceride transfer protein inhibitor; and alirocumab (Praluent, Sanofi-Aventis/Regeneron) and evolocumab (Repatha, Amgen), PCSK9 inhibitors, are currently approved by the U.S. Food and Drug Administration for use in FH. This review highlights traditional as well as emerging contemporary therapies with supporting clinical data to evaluate current recommendations and discuss the future direction of FH management.

Triglyceride Treatment in the Age of Cholesterol Reduction

Cholesterol reduction has markedly reduced major cardiovascular disease (CVD) events and shown regression of atherosclerosis in some studies. However, CVD has for decades also been associated with increased levels of circulating triglyceride (TG)-rich lipoproteins. Whether this is due to a direct toxic effect of these lipoproteins on arteries or whether this is merely an association is unresolved. More recent genetic analyses have linked genes that modulate TG metabolism with CVD. Moreover, analyses of subgroups of hypertriglyceridemic (HTG) subjects in clinical trials using fibric acid drugs have been interpreted as evidence that TG reduction reduces CVD events. This review will focus on how HTG might cause CVD, whether TG reduction makes a difference, what pathophysiological defects cause HTG, and what options are available for treatment.

From Lipids to Inflammation: New Approaches to Reducing Atherosclerotic Risk

The introduction of statins ≈ 30 years ago ushered in the era of lipid lowering as the most effective way to reduce risk of atherosclerotic cardiovascular disease. Nonetheless, residual risk remains high, and statin intolerance is frequently encountered in clinical practice. After a long dry period, the field of therapeutics targeted to lipids and atherosclerosis has entered a renaissance. Moreover, the demonstration of clinical benefits from the addition of ezetimibe to statin therapy in subjects with acute coronary syndromes has renewed the enthusiasm for the cholesterol hypothesis and the hope that additional agents that lower low-density lipoprotein will decrease risk of atherosclerotic cardiovascular disease. Drugs in the orphan disease category are now available for patients with the most extreme hypercholesterolemia. Furthermore, discovery and rapid translation of a novel biological pathway has given rise to a new class of cholesterol-lowering drugs, the proprotein convertase subtilisin kexin-9 inhibitors. Trials of niacin added to statin have failed to demonstrate cardiac benefits, and 3 cholesterol ester transfer protein inhibitors have also failed to reduce atherosclerotic cardiovascular disease risk, despite producing substantial increases in HDL levels. Although the utility of triglyceride-lowering therapies remains uncertain, 2 large clinical trials are testing the influence of omega-3 polyunsaturated fatty acids on atherosclerotic events in hypertriglyceridemia. Novel antisense therapies targeting apolipoprotein C-III (for triglyceride reduction) and apo(a) (for lipoprotein(a) reduction) are showing a promising trajectory. Finally, 2 large clinical trials are formally putting the inflammatory hypothesis of atherosclerosis to the test and may open a new avenue for cardiovascular disease risk reduction.

The Role of Ezetimibe in the Treatment of Cardiovascular Disease

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Despite the success of treatment of CVD with statin therapy, a number of patients remain at high risk for CVD. Ezetimibe is a non-statin agent that inhibits intestinal cholesterol absorption, leading to reductions in low-density lipoprotein cholesterol (LDL-C). A number of clinical studies evaluating the use of ezetimibe therapy have resulted in discordant data regarding its safety and efficacy. In this review, we discuss the findings from these studies as well as potential indications for the use of ezetimibe for LDL-C lowering and cardiovascular event reduction.

Ezetimibe plus moderate-dose simvastatin after acute coronary syndrome: what are we IMPROVEing on?

The recent IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) is the first study to demonstrate a significant benefit of another medication (ezetimibe) on top of statin therapy in patients who have recently experienced an acute coronary syndrome. Despite the fact that ezetimibe led to positive results on the primary endpoint, the clinical benefit translated to real-life practice is only modest at best. However, this is the first major trial to demonstrate a significant benefit of a lipid medication in addition to statins. We explore the strengths and weaknesses of IMPROVE-IT in the context of current-day acute coronary syndrome practice, where high-dose statins now are prescribed widely.

Novel treatments for familial hypercholesterolemia: pharmacogenetics at work

The familial hypercholesterolemias (FHs) are inherited disorders of lipoprotein metabolism that are among the most prevalent genetically inherited disorders. Various genetic mutations ultimately lead to greatly increased low-density lipoprotein-cholesterol (LDL-C) levels over a lifetime. Consequently, patients with FH develop coronary artery disease at significantly earlier ages and at a greater frequency than the general population. Current therapies revolve around aggressive lifestyle modifications, cholesterol-lowering medications, and in some cases LDL apheresis. Despite maximal medical therapy, LDL-C is not sufficiently reduced in some patients, and they remain at a substantially increased risk of coronary heart disease. Recent advances in genetic-based pharmacology have enabled the development of three novel classes of medications for FH. Two of those compounds, mipomersen and lomitapide, result in decreased LDL-C production and were approved by the Food and Drug Administration in the past 18 months for treatment of homozygous FH. Mipomersen is an antisense oligonucleotide that inhibits the translation of apolipoprotein B-100, and lomitapide is an inhibitor of the microsomal triglyceride transfer protein, which prevents the incorporation of triglycerides into lipoproteins. A third class of drugs, the proprotein convertase subtilisin/kexin type 9 inhibitors, is still in development, although studies in patients with heterozygous or receptor-defective homozygous FH have demonstrated substantial reductions in LDL-C by decreasing the degradation of LDL receptors. Development of these novel treatments for hypercholesterolemia resulted from the application of known genetic mutations and is the focus of this review.

Landmark lipid-lowering trials in the primary prevention of cardiovascular disease

Although atherosclerotic cardiovascular disease (CVD) is the most common cause of morbidity and mortality in the world, the long disease latency affords ample opportunity for preventive care. Indeed, lifelong exposure to atherogenic apoliprotein B-containing lipoproteins has consistently been shown to increase the cumulative risk of suffering a CVD event, including myocardial infarction, stroke, and symptomatic peripheral arterial disease. Over the past 25 years, lipid-lowering therapies have been developed that are proven to not only lower cholesterol, but also to decrease adverse CVD events and CVD mortality. This review will highlight several key clinical trials encompassing several classes of lipid-lowering medications that have provided clinicians with an evidence-based framework for managing their patients' cardiovascular risk.

Therapeutic strategies to deplete macrophages in atherosclerotic plaques

Macrophages can be found in all stages of atherosclerosis and are major contributors of atherosclerotic plaque development, progression and destabilization. Continuous recruitment of monocytes drives this chronic inflammatory disease, which can be intervened by several strategies: reducing the inflammatory stimulus by lowering circulating lipids and promoting cholesterol efflux from plaque, direct and indirect targeting of adhesion molecules and chemokines involved in monocyte adhesion and transmigration and inducing macrophage death in atherosclerotic plaques in combination with anti-inflammatory drugs. This review discusses the outlined strategies to deplete macrophages from atherosclerotic plaques to promote plaque stabilization.

Inhibition of cholesterol absorption: targeting the intestine

Atherosclerosis, the gradual formation of a lipid-rich plaque in the arterial wall is the primary cause of Coronary Artery Disease (CAD), the leading cause of mortality worldwide. Hypercholesterolemia, elevated circulating cholesterol, was identified as a key risk factor for CAD in epidemiological studies. Since the approval of Mevacor in 1987, the primary therapeutic intervention for hypercholesterolemia has been statins, drugs that inhibit the biosynthesis of cholesterol. With improved understanding of the risks associated with elevated cholesterol levels, health agencies are recommending reductions in cholesterol that are not achievable in every patient with statins alone, underlying the need for improved combination therapies. The whole body cholesterol pool is derived from two sources, biosynthesis and diet. Although statins are effective at reducing the biosynthesis of cholesterol, they do not inhibit the absorption of cholesterol, making this an attractive target for adjunct therapies. This report summarizes the efforts to target the gastrointestinal absorption of cholesterol, with emphasis on specifically targeting the gastrointestinal tract to avoid the off-target effects sometimes associated with systemic exposure.

Preventive aspects in peripheral artery disease

The prevalence of peripheral artery disease is steadily increasing and is associated with significant morbidity, including a significant percentage of amputations. Peripheral artery disease often goes undiagnosed, making its prevention increasingly important. Patients with peripheral arterial disease are at increased risk of adverse cardiovascular outcomes which makes prevention even more important. Several risk factors have been identified in the pathophysiology of peripheral artery disease which should be modified to decrease risk. Smoking, hyperlipidemia, hypertension, and diabetes are among proven risk factors for the development of peripheral artery disease, thus smoking cessation, lipid control, blood pressure control, and glucose control have been tried and shown to be effective in preventing the morbidity associated with this disease. Pharmacologic agents such as aspirin and clopidogrel alone or in combination have been shown to be effective, though risk of bleeding might be increased with the combination. Anticoagulation use is recommended only for acute embolic cases. Other treatment modalities that have been tried or are under investigation are estrogen replacement, naftidrofuryl, pentoxifylline, hyperbaric oxygen, therapeutic angiogenesis, and advanced glycation inhibitors. The treatment for concomitant vascular diseases does not change in the presence of peripheral artery disease, but aggressive management of risk factors should be undertaken in such cases.

Surrogate end points in secondary analyses of cardiovascular trials

A surrogate end point is one that is used as a substitute for a clinical end point of more direct interest, usually for reasons of practicality, and that is expected to predict clinical benefit. Surrogate end points play a critical role in the advancement of all medical research, and cardiovascular (CV) research in particular. However, the relationship between a surrogate end point and its clinical end point is usually complex, and there are many examples where results based on surrogates have proved to be misleading. Secondary analyses of existing clinical trial data are likely to involve surrogate end points, if only because clinical end points will have been extensively studied as part of the primary analysis of a trial large enough to collect useful clinical end point data. Validation of a surrogate end point is a laudable goal for a secondary analysis of a large clinical end point trial (or meta-analysis of multiple smaller trials), and the result may be an important new tool for further study of a class of compounds in a particular disease context. Secondary analyses using surrogate end points may also provide new insight into disease or treatment mechanism, but as with any surrogate end point analysis, the results can mislead, and the existing literature is heavy on application and light on methodology. Surrogate end points often substitute efficiency for clarity, and while many interesting and potentially informative secondary analyses of CV trials will involve surrogates, results are likely to be ambiguous and should be interpreted with care.

Incidental cardiac findings on computed tomography imaging of the thorax

Background

Investigation of pulmonary pathology with computed tomography also allows visualisation of the heart and major vessels. We sought to explore whether clinically relevant cardiac pathology could be identified on computed tomography pulmonary angiograms (CTPA) requested for the exclusion of pulmonary embolism (PE). 100 consecutive CT contrast-enhanced pulmonary angiograms carried out for exclusion of PE at a single centre were assessed retrospectively by two cardiologists.

Findings

Evidence of PE was reported in 5% of scans. Incidental cardiac findings included: aortic wall calcification (54%), coronary calcification (46%), cardiomegaly (41%), atrial dilatation (18%), mitral annulus calcification (15%), right ventricular dilatation (11%), aortic dilatation (8%) and right ventricular thrombus (1%). Apart from 3 (3%) reports describing cardiomegaly, no other cardiac findings were described in radiologists' reports. Other reported pulmonary abnormalities included: lung nodules (14%), lobar collapse/consolidation (8%), pleural effusion (2%), lobar collapse/consolidation (8%), emphysema (6%) and pleural calcification (4%).

Conclusions

CTPAs requested for the exclusion of PE have a high yield of cardiac abnormalities. Although these abnormalities may not have implications for acute clinical management, they may, nevertheless, be important in long-term care.

Current therapy for patients with sitosterolemia--effect of ezetimibe on plant sterol metabolism

Sitosterolemia is a rare, autosomal recessive inherited sterol storage disease associated with high tissue and serum plant sterol concentrations, caused by mutations in the adenosine triphosphate-bind-ing cassette (ABC) transporter ABCG5 or ABCG8 genes. Markedly increased serum concentration of plant sterols. such as sitosterol and campesterol, cause premature atherosclerosis and massive xanthomas. Hitherto known treatments for sitosterolemia, including a low-sterol diet, bile-salt binding resins, ileal bypass surgery and low density lipoprotein (LDL) apheresis have not yielded sufficient reduction of serum plant sterol levels and many patients show a sustained elevation of plant sterol levels, subsequently developing premature atherosclerotic cardiovascular diseases. Ezetimibe, an inhibitor of intestinal cholesterol absorption through its binding to Niemann-Pick C1-like 1 (NPC1L1), has been widely used for decreasing serum LDL-cholesterol levels in patients with hypercholesterolemia. Ezetimibe also reduces the gastrointestinal absorption of plant sterols, thereby also lowering the serum concentrations of plant sterols. This pharmacological property of ezetimibe shows its potential as a novel effective therapy for sitosterolemia. In the current review, we discuss the current therapy for patients with sitosterolemia and present two Japanese adolescent patients with this disease, one of whom underwent percutaneous coronary intervention for accelerated coronary atherosclerosis. Ezetimibe administration in addition to conventional drug therapy successfully reduced serum sitosterol levels by 51.3% and 48.9%, respectively, in the two patients, demonstrating ezetimibe as a novel and potent treatment agent for sitosterolemia that could work additively with conventional drug therapy.

Findings of clinical trials that evaluate the impact of medical therapies on progression of atherosclerosis

BACKGROUND

Arterial wall imaging has been increasingly employed in clinical trials to evaluate the impact of medical therapies on progression of atherosclerosis.

SCOPE

A selective overview of major findings from clinical trials that assessed the impact of medical therapies on atherosclerosis progression.

FINDINGS

Targeting established risk factors including LDL cholesterol, HDL cholesterol and blood pressure has a beneficial impact on disease progression.

CONCLUSION

As a result, vascular imaging has been employed in the early evaluation of experimental therapies.

Longitudinal ultrasound evaluation of carotid atherosclerosis in one, two and three dimensions

The aim of this study was to compare the sensitivity of three ultrasound phenotypes of carotid atherosclerosis in a longitudinal study of patients with diabetic nephropathy. B-mode ultrasound-derived intima-media thickness (IMT), total plaque area (TPA) as well as three-dimensional ultrasound (3DUS) vessel wall volume (VWV) of the common carotid artery (CCA) (VWV(CCA)) and internal carotid artery (ICA). (VWV(CCA+ICA)) were all evaluated in subjects enrolled in a randomized placebo-controlled double blind study of vitamin B therapy. Of 106 subjects randomized, 77 subjects were scanned at baseline and 2.3 +/- 1 y later (range: 0.5 to 4.5 y); of these subjects, 71 had images of sufficient quality for complete analysis of all three measurements. Subjects were analyzed according to the two treatment groups (A and B) and the analysis was performed blinded to treatment group description to prevent any potential for bias in future analyses. There were differences in sensitivity to longitudinal changes observed in all the ultrasound measurements. Specifically, there was no difference in IMT change between treatment groups (0.02 +/- 0.07 mm/y and 0.02 +/- 0.1 mm/y p = 0.15, group A and B, respectively, rates not different from zero [p > 0.05]) or TPA rate between treatment groups (0.09 +/- 0.2 cm(2)/y, significantly different from 0, p = 0.013 and -0.02 +/- 0.3 cm(2)/y in group A and B, respectively). However, the VWV(CCA+ICA) rate of change was significantly greater than 0 for group B (53 +/- 110 mm(3)/y) (p = 0.008), which was significantly (p = 0.034) higher than the rate of change of VWV(CCA+ICA) (nonsignificant, p = 0.6) for group A (-12 +/- 137 mm(3)/y). The relationship between DeltaVWV and DeltaIMT was significant, such that in group A, DeltaVWV(CCA) was positively associated with DeltaIMT (r = 0.44, p < 0.05), and in group B, DeltaVWV(CCA) was negatively correlated with DeltaIMT (r = -0.44, p < 0.01). These results suggest that 3DUS-derived VWV provides necessary and sufficient sensitivity and specificity to measure longitudinal changes in small numbers of carotid atherosclerosis patients at risk of disease progression and over short periods of time.

Current and emerging paradigms in the therapeutic management of atherosclerosis

BACKGROUND

The pathogenesis of atherosclerosis lies in abnormalities in lipoprotein metabolism leading to pathological interactions with vessel walls and the release of inflammatory components, which further aggravate the disease condition.

OBJECTIVE

To elucidate current and emerging trends in drug discovery towards the development of new entities regulating lipoprotein metabolism and inflammatory components to combat the progression of atherosclerosis.

METHODS

Research/review articles in the public domain and press releases were employed.

RESULTS/CONCLUSION

With the recent failure of torcetrapib and succinobucol, drug discovery and development efforts towards the treatment of atherosclerosis have received a big jolt and have been slowed down to a certain extent [corrected]. But this could be a starting point for several new mechanisms that are emerging to discover new drugs to combat the disease.

Rationale and design of IMPROVE-IT (IMProved Reduction of Outcomes: Vytorin Efficacy International Trial): comparison of ezetimbe/simvastatin versus simvastatin monotherapy on cardiovascular outcomes in patients with acute coronary syndromes

BACKGROUND

Reduction in low-density lipoprotein cholesterol (LDL-C) improves clinical outcomes in patients with chronic coronary artery disease and acute coronary syndromes (ACSs). The combination of ezetimibe/simvastatin produces greater reductions in LDL-C compared to simvastatin monotherapy. The IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) is a multicenter, randomized, double-blind, active-control trial designed to test the hypothesis that the addition of ezetimibe to statin therapy, using ezetimibe/simvastatin, will translate into increased clinical benefit on cardiovascular outcomes relative to simvastatin monotherapy in patients with ACS.

STUDY DESIGN

The study will recruit up to 18,000 moderate- to high-risk patients stabilized after ACS. Patients are randomized in a 1:1 ratio to once-daily doses of either ezetimibe/simvastatin 10/40 mg or simvastatin monotherapy 40 mg. Follow-up visits are at 1 and 4 months, and every 4 months thereafter. If consecutive measures of LDL-C are >79 mg/dL at follow-up visits, the simvastatin dose will be increased to 80 mg in a double-blind manner. The primary end point is the first occurrence of cardiovascular death, nonfatal myocardial infarction, rehospitalization for unstable angina, coronary revascularization (occurring at least 30 days after randomization), or stroke. Patients will be followed for a minimum of 2.5 years and until at least 5,250 patients experience a primary end point.

SUMMARY

IMPROVE-IT will determine whether the addition of ezetimibe to statin therapy, using ezetimibe/simvastatin, improves cardiovascular outcomes compared with simvastatin monotherapy in patients after ACS. In addition, the difference in achieved LDL-C levels between the groups will provide data on whether the target for LDL-C lowering should be reduced further.

Comparison of B-mode ultrasound, 3-dimensional ultrasound, and magnetic resonance imaging measurements of carotid atherosclerosis

OBJECTIVE

We compared the intraobserver and interscan variability of carotid atherosclerosis measured using B-mode ultrasound for quantifying intima media thickness (IMT), 3-dimensional ultrasound (3DUS) for quantifying vessel wall volume (VWV) and total plaque volume (TPV), and magnetic resonance imaging (MRI) for measuring VWV. We also evaluated the associations of these measurements and sample sizes required to detect specific changes in patients with moderate atherosclerosis.

METHODS

Ten patients were evaluated with B-mode ultrasound, MRI, and 3DUS twice within 14 +/- 2 days. Measurements of IMT, MRI VWV, 3DUS VWV, and 3DUS TPV were performed by single observers using manual (VWV and TPV) and semiautomated (IMT) segmentation.

RESULTS

Intraobserver coefficients of variation were 3.4% (IMT), 4.7% (3DUS VWV), 6.5% (MRI VWV), and 23.9% (3DUS TPV). Interscan coefficients of variation were 8.1% (MRI VWV), 8.9% (IMT), 13.5% (3DUS VWV), and 46.6% (3DUS TPV). Scan-rescan linear regressions were significant for 3DUS TPV (R(2) = 0.57), 3DUS VWV (R(2) = 0.59), and IMT (R(2) = 0.75) and significantly different (P < .05) for MRI VWV (R(2) = 0.87).

CONCLUSIONS

B-mode ultrasound-derived IMT provided the highest intraobserver and interscan reproducibility. Three-dimensional measurements of VWV derived from 3DUS and MRI provided both high sensitivity and high intraobserver and interscan reliability.

Subclinical atherosclerosis: what it is, what it means and what we can do about it

Atherosclerosis is a chronic, progressive, inflammatory disease with a long asymptomatic phase. Disease progression can lead eventually to the occurrence of acute cardiovascular events such as myocardial infarction, unstable angina pectoris and sudden cardiac death. While the disease is still in a subclinical stage, however, the presence of atherosclerosis can be identified by several methods, including coronary angiography, intravascular ultrasonography, B-mode ultrasonography, computed tomography and magnetic resonance imaging. Based on the results of imaging studies, statin therapy can slow, halt or even reverse the progression of atherosclerotic disease, depending on the intensity of treatment. Whether to screen and treat patients for subclinical atherosclerosis remains controversial. Although atheromatous plaque burden reduction has not yet been definitively correlated with significant decreases in risk for acute coronary events in asymptomatic patients, statin therapy contributes significantly to the risk reduction observed in clinical trials in patients with and without overt coronary disease.

Carotid intima-media thickness (cIMT): a useful clinic tool or research luxury? Another view of the ENHANCE trial

The ENHANCE trial was the first trial of ezetimibe- simvastatin with a surrogate marker as a primary endpoint. The combination of the 2 drugs is highly effective in reducing total cholesterol and low-density lipoprotein cholesterol levels and with a positive profile on high-density lipoprotein cholesterol. However, there are no data as yet about the clinical effectiveness of the addition of ezetimibe on statin therapy and whether this provides a further reduction of cardiovascular events. The answer to the clinical hard endpoints question will be provided in 2012 by the IMPROVE-IT trial comparing the effectiveness of simvastatin 40 mg plus ezetimibe versus simvastatin 40 mg on 18,000 acute coronary syndrome patients. The ENHANCE study failed in its primary endpoint, carotid intima-media thickness reduction, but has various methodological weaknesses that makes it very difficult to accept the American College of Cardiology statement that ezetimibe should be the last resort after trying all other available treatments.

Ezetimibe: cholesterol lowering and beyond

Ezetimibe is a cholesterol absorption inhibitor that blocks the intestinal absorption of both biliary and dietary cholesterol. It appears to exert its effect by blocking intestinal sterol transporters, specifically Niemann-Pick C1-like 1 proteins, thereby inhibiting the intestinal absorption of cholesterol, phytosterols and certain oxysterols. Ezetimibe monotherapy and in combination with statin therapy is primarily indicated for lowering LDL-cholesterol levels. In addition, it may favorably affect other parameters that could potentially further reduce atherosclerotic coronary heart disease risk, such as raising HDL-cholesterol and lowering levels of triglycerides, non-HDL-cholesterol, apolipoprotein B and remnant-like particle cholesterol. Further effects of ezetimibe include a reduction in circulating phytosterols and oxysterols and, when used in combination with statins, a reduction in high-sensitivity C-reactive protein. The clinical significance of the LDL-cholesterol lowering and other effects of ezetimibe is being evaluated in clinical outcome studies.

Simvastatin with or without ezetimibe in familial hypercholesterolemia

BACKGROUND

Ezetimibe, a cholesterol-absorption inhibitor, reduces levels of low-density lipoprotein (LDL) cholesterol when added to statin treatment. However, the effect of ezetimibe on the progression of atherosclerosis remains unknown.

METHODS

We conducted a double-blind, randomized, 24-month trial comparing the effects of daily therapy with 80 mg of simvastatin either with placebo or with 10 mg of ezetimibe in 720 patients with familial hypercholesterolemia. Patients underwent B-mode ultrasonography to assess the intima-media thickness of the walls of the carotid and femoral arteries. The primary outcome measure was the change in the mean carotid-artery intima-media thickness, which was defined as the average of the means of the far-wall intima-media thickness of the right and left common carotid arteries, carotid bulbs, and internal carotid arteries.

RESULTS

The primary outcome, the mean (+/-SE) change in the carotid-artery intima-media thickness, was 0.0058+/-0.0037 mm in the simvastatin-only group and 0.0111+/-0.0038 mm in the simvastatin-plus-ezetimibe (combined-therapy) group (P=0.29). Secondary outcomes (consisting of other variables regarding the intima-media thickness of the carotid and femoral arteries) did not differ significantly between the two groups. At the end of the study, the mean (+/-SD) LDL cholesterol level was 192.7+/-60.3 mg per deciliter (4.98+/-1.56 mmol per liter) in the simvastatin group and 141.3+/-52.6 mg per deciliter (3.65+/-1.36 mmol per liter) in the combined-therapy group (a between-group difference of 16.5%, P<0.01). The differences between the two groups in reductions in levels of triglycerides and C-reactive protein were 6.6% and 25.7%, respectively, with greater reductions in the combined-therapy group (P<0.01 for both comparisons). Side-effect and safety profiles were similar in the two groups.

CONCLUSIONS

In patients with familial hypercholesterolemia, combined therapy with ezetimibe and simvastatin did not result in a significant difference in changes in intima-media thickness, as compared with simvastatin alone, despite decreases in levels of LDL cholesterol and C-reactive protein. (ClinicalTrials.gov number, NCT00552097 [ClinicalTrials.gov].).

Can intensive statin therapy halt the progression of atherosclerosis? Recent evidence and potential implications for patient management

A number of studies using various imaging techniques have demonstrated that intensive lipid lowering with statins can halt or delay the progression of atherosclerosis and even, in some cases, lead to plaque regression. Improvements in atheroma burden with intensive statin therapy appear to be related not just to decreasing low-density lipoprotein cholesterol but also to anti-inflammatory and antiproliferative effects. Clinical trial results also suggest that achieving low-density lipoprotein cholesterol levels even lower than those currently recommended can produce improved clinical outcomes across a range of patient types. Given this body of evidence, it appears appropriate to use intensive statin therapy to treat dyslipidemic patients at high risk for coronary heart disease.

Ezetimibe-associated adverse effects: what the clinician needs to know

OBJECTIVE

Ezetimibe is a relatively new lipid lowering agent, which is indicated for the treatment of primary hypercholesterolaemia, either as monotherapy or in combination with other hypolipidaemic drugs. The objective of the present article was to review the side effects attributed to ezetimibe administration and discuss their possible underlying mechanisms. Moreover, we aimed to comment on the possible drug interactions of ezetimibe and present current guidelines regarding its safe use.

METHODS

Relevant articles were identified through a PubMed search (up to June 2007).

RESULTS

Compelling evidence from the majority of the data reviewed here showed that adverse effects associated with ezetimibe use are few and mild without having been associated with serious clinical outcomes. In most studies ezetimibe has not been associated with increased rates of myopathy or rhabdomyolysis, whether used alone or in combination with statins, although there have been some case reports of myopathy attributed to this agent. Moreover, ezetimibe has been associated with mild elevations of liver transaminases, mainly in combination with a statin. Other side effects are extremely rare. It should be noted, however, there are no long-term safety data or outcome studies for ezetimibe yet.

CONCLUSIONS

Ezetimibe is a safe alternative option for hyperlipidaemic patients intolerant to other lipid lowering drugs as well as a beneficial supplementary agent for patients who do not reach the recommended serum cholesterol level with their current hypolipidaemic treatment. However, as is the case with all new medications, physicians should be alert to recognise adverse effects associated with ezetimibe and report them to regulatory authorities.