Smoking diminishes the beneficial effect of statins: observations from the landmark trials

The Role of Smoking in the Mechanisms of Development of Chronic Obstructive Pulmonary Disease and Atherosclerosis

Tobacco smoking is a major cause of chronic obstructive pulmonary disease (COPD) and atherosclerotic cardiovascular disease (ASCVD). These diseases share common pathogenesis and significantly influence each other's clinical presentation and prognosis. There is increasing evidence that the mechanisms underlying the comorbidity of COPD and ASCVD are complex and multifactorial. Smoking-induced systemic inflammation, impaired endothelial function and oxidative stress may contribute to the development and progression of both diseases. The components present in tobacco smoke can have adverse effects on various cellular functions, including macrophages and endothelial cells. Smoking may also affect the innate immune system, impair apoptosis, and promote oxidative stress in the respiratory and vascular systems. The purpose of this review is to discuss the importance of smoking in the mechanisms underlying the comorbid course of COPD and ASCVD.

Cardiovascular Risk and Statin Therapy Considerations in Women

Despite major progress in the prevention and treatment of cardiovascular diseases, women remain an underdiagnosed and insufficiently treated group, with higher hospitalization and death rates compared to men. Obesity, more frequently encountered in women, raises the risk of metabolic syndrome and cardiovascular diseases as women age. There are some differences based on sex regarding the screening, diagnosis, and treatment of dyslipidemia, as it has been observed that women are less frequently prescribed statins and, when they are, they receive lower doses, even after myocardial infarction or coronary revascularization. Real-life data show that, compared to men, women are at higher risk of non-adherence to statin treatment and are more predisposed to discontinue treatment because of side effects. Statin metabolism has some particularities in women, due to a lower glomerular filtration rate, higher body fat percentage, and overall faster statin metabolism. In women of fertile age, before initiating statin treatment, contraception methods should be discussed because statins may have teratogenic effects. Older women have a higher likelihood of polypharmacy, with greater potential for drug interactions when prescribing a statin.

Lifestyle Changes in Relation to Initiation of Antihypertensive and Lipid-Lowering Medication: A Cohort Study

Background Lifestyle modification is a key component of cardiovascular disease prevention before and concurrently with pharmacologic interventions. We evaluated whether lifestyle factors change in relation to the initiation of antihypertensive or lipid-lowering medication (statins). Methods and Results The study population comprised 41 225 participants of the FPS (Finnish Public Sector) study aged ≥40 years who were free of cardiovascular disease at baseline and responded to ≥2 consecutive surveys administered in 4-year intervals in 2000-2013. Medication use was ascertained through pharmacy-claims data. Using a series of pre-post data sets, we compared changes in body mass index, physical activity, alcohol consumption, and smoking between 8837 initiators and 46 021 noninitiators of antihypertensive medications or statins. In participants who initiated medication use, body mass index increased more (difference in change 0.19; 95% CI, 0.16-0.22) and physical activity declined (-0.09 metabolic equivalent of task hour/day; 95% CI, -0.16 to -0.02) compared with noninitiators. The likelihood of becoming obese (odds ratio: 1.82; 95% CI, 1.63-2.03) and physically inactive (odds ratio: 1.08; 95% CI, 1.01-1.17) was higher in initiators. However, medication initiation was associated with greater decline in average alcohol consumption (-1.85 g/week; 95% CI, -3.67 to -0.14) and higher odds of quitting smoking (odds ratio for current smoking in the second survey: 0.74; 95% CI, 0.64-0.85). Conclusions These findings suggest that initiation of antihypertensive and statin medication is associated with lifestyle changes, some favorable and others unfavorable. Weight management and physical activity should be encouraged in individuals prescribed these medications.

Interaction of cigarette smoke condensate and some of its components with chlorpromazine toxicity on Saccharomyces cerevisiae

Chlorpromazine (CPZ) is an antipsychotic phenothiazine which is still commonly prescribed though it causes idiosyncratic toxicity such as cholestasis. CPZ toxicity mechanisms involve oxidative stress among others. Cigarette smoke (CS) causes deleterious effects through diverse mechanisms such as oxidative stress. CS alters drug metabolizing enzymes expression and drug transporters expression and activity in animal cell models as well as in Saccharomyces cerevisiae. CS therefore alters pharmacokinetic and pharmacodynamics of many drugs including CPZ and caffeine whose toxicity is promoted by CS condensate (CSC). CSC interaction with CPZ toxicity deserves investigation. In this study, CSC exerted mild toxicity on Saccharomyces cerevisiae which resisted to this chemical stress after several hours. CPZ toxicity on yeast was dose-dependent and the cells resisted to CPZ up to 40 µM after 24 h of treatment. Yeast cells treated simultaneously with CPZ and a nontoxic CSC dose were less sensitive to CPZ. CSC probably triggers cross-resistance to CPZ. Using Sod1 mutant strain, we showed that this gene is potentially involved in the potential cross-resistance. Other genes encoding stress-related transcription factors could be involved in this process. Nicotine and cadmium chloride, which caused a dose-dependent toxicity individually, acted with CPZ in an additive or synergistic manner in terms of toxicity. Although our results cannot be extrapolated to humans, they clearly show that CSC and its components interact with CPZ toxicity.

Tobacco smoking and its drug interactions with comedications involving CYP and UGT enzymes and nicotine

Tobacco smoking is a global public health threat causing several illnesses including cardiovascular disease (Myocardial infarction), cerebrovascular disease (Stroke), peripheral vascular disease (Claudication), chronic obstructive pulmonary disease, asthma, reduced female infertility, sexual dysfunction in men, different types of cancer and many other diseases. It has been estimated in 2015 that approximately 1.3 billion people smoke, around the globe. Use of medications among smokers is more common, nowadays. This review is aimed to identify the medications affected by smoking, involving Cytochrome P450 (CYP) and uridine diphosphate-glucuronosyltransferases (UGTs) enzymes and Nicotine. Polycyclic aromatic hydrocarbons (PAHs) of tobacco smoke have been associated with the induction of CYP enzymes such as CYP1A1, CYP1A2 and possibly CYP2E1 and UGT enzymes. The drugs metabolized by CYP1A1, CYP1A2, CYP2E1 and UGT enzymes might be affected by tobacco smoking and the smokers taking medications metabolized by those enzymes, may need higher doses due to decreased plasma concentrations through enhanced induction by PAHs of tobacco smoke. The prescribers and the pharmacists are required to be aware of medications affected by tobacco smoking to prevent the toxicity-associated complications during smoking cessation.

Chronic Nicotine Exposure Reduces Antioxidant Function of Simvastatin in Renal Proximal Tubule Cells

BACKGROUND/AIM

We have previously reported that simvastatin exhibits antioxidant properties via extracellular signal-regulated kinase (ERK)/cAMP-response element binding (CREB) protein-dependent induction of heme oxygenase-1 (HO1) and chronic nicotine exposure inhibits ERK/CREB signaling in renal proximal tubule cells (through p66shc). Herein, whether nicotine dampens simvastatin-dependent HO1 induction was determined.

MATERIALS AND METHODS

Renal proximal tubule (NRK52E) cells were pre-treated with 200 μM nicotine for 24 h followed by 10 μM simvastatin. Promoter activity of HO1 and manganese superoxide dismutase (MnSOD) and activation of CREB and ERK (via ELK1) were determined in luciferase reporter assays. CREB and p66shc were modulated via genetic means.

RESULTS

Nicotine suppressed simvastatin-dependent activation of HO1 and MnSOD promoters and activity of CREB and ELK1 via p66shc. Overexpression of CREB or knockdown of p66shc restored simvastatin-dependent induction of HO1 and MnSOD in the presence of nicotine.

CONCLUSION

Antioxidant efficiency of simvastatin might be significantly lessened in smokers/E-cigarette users.

The effect of statins on cardiovascular outcomes by smoking status: A systematic review and meta-analysis of randomized controlled trials

Smoking is an important risk factor for cardiovascular disease (CVD) morbidity and mortality. The impact of statin therapy on CVD risk by smoking status has not been fully investigated. Therefore we assessed the impact of statin therapy on CVD outcomes by smoking status through a systematic review of the literature and meta-analysis of available randomized controlled trials (RCTs). The literature search included EMBASE, ProQuest, CINAHL and PUBMED databases to 30 January 2016 to identify RCTs that investigated the effect of statin therapy on cumulative incidence of major CVD endpoints (e.g. non-fatal myocardial infarction, revascularization, unstable angina, and stroke). Relative risks (RR) ratios were calculated from the number of events in different treatment groups for both smokers and non-smokers. Finally 11 trials with 89,604 individuals were included. The number of smokers and non-smokers in the statin groups of the analyzed studies was 8826 and 36,090, respectively. The RR for major CV events was 0.73 (95% confidence interval [CI]: 0.67-0.81; p<0.001) in nonsmokers and 0.72 (95%CI: 0.64-0.81; p<0.001) in smokers. Moderate to high heterogeneity was observed both in non-smokers (I²=77.1%, p<0.001) and in smokers (I²=51.6%, p=0.024) groups. Smokers seemed to benefit slightly more from statins than non-smokers according to the number needed to treat (NNT) analysis (23.5 vs 26.8) based on RRs applied to the control event rates. The number of avoided events per 1000 individuals was 42.5 (95%CI: 28.9-54.6) in smokers and 37.3 (95%CI: 27.2-46.4) in non-smokers. In conclusion, this meta-analysis suggests that the effect of statins on CVD is similar for smokers and non-smokers, but in terms of NNTs and number of avoided events, smokers seem to benefit more although non-significantly.

Do statin users adhere to a healthy diet and lifestyle? The Australian Diabetes, Obesity and Lifestyle Study

Background Lifestyle and dietary advice typically precedes or accompanies the prescription of statin medications. However, evidence for adherence to this advice is sparse. The objective was to compare saturated fat intake, exercise, alcohol consumption and smoking between statin users and non-users in Australia. Methods Data were analysed for 4614 participants aged ≥37 years in the Australian Diabetes, Obesity and Lifestyle study in 2011-2012. Statin use, smoking status and physical activity were self-reported. Saturated fat and alcohol intake were measured via a food frequency questionnaire. Multinomial logistic regression was used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between statin use and the four lifestyle factors. All models were adjusted for age, sex, education, number of general practitioner visits, body mass index, hypertension, diabetes and prior cardiovascular diseases. Results In total 1108 (24%) participants used a statin. Statin users were 29% less likely to be within the highest quartile versus the lowest quartile of daily saturated fat intake compared to non-users (OR 0.71, 95% CI 0.54-0.94). There were no statistically significant associations between statin use and smoking, physical activity or alcohol consumption. Conclusions Smoking status, alcohol consumption and exercise level did not differ between users and non-users of statins. However, statin users were less likely to consume high levels of saturated fat than non-users. We found no evidence that people took statins to compensate for a poor diet or lifestyle.

Risk Modification in Patients with Peripheral Arterial Disease: A Retrospective Survey

Peripheral arterial disease (PAD) is underdiagnosed and undertreated. This is despite the high vascular morbidity and mortality rates associated with PAD. There is also evidence that quitting smoking, improving the lipid profile, lowering the blood pressure, and administering antiplatelet drugs reduce the risk of vascular events in these patients. Secondary prevention for patients with PAD is yet to meet the standard of care for those with ischemic heart disease. The authors surveyed 200 claudicants attending a vascular clinic with additional follow-up in a risk modification clinic. After a median follow-up of 28 months (range: 6-65) there was a significant (p=0.001) improvement in walking distance; 34 patients (17%) had a vascular ischemic event. Of those, 11 patients (5.5%) had worsening intermittent claudication and 9 had a stroke/transient ischemic attack; 9 events (4.5%) were fatal. The lipid targets were met in 76% the patients. Half the smokers quit smoking and 94% of the patients were taking antiplatelet drugs or anticoagulants. Blood pressure reached the accepted target in 87% of the patients. Secondary prevention in patients with PAD may reduce the risk of vascular events. Aggressive risk modification is therefore recommended.

The Effect of Short-Term Treatment with Simvastatin on Renal Function in Patients with Peripheral Arterial Disease

The objective of this study was to investigate the effects of lipid-lowering treatment on renal function in patients with peripheral arterial disease (PAD). This was a retrospective study of hyperlipidemic claudicants referred to a vascular surgery and risk modification clinic. Serum creatinine and urate concentrations and the fasting lipid profile were measured pretreatment and after 3-4 months of treatment with 20 mg/day simvastatin. In 103 consecutive patients with PAD (57 men; 46 women), median age 67 years (range: 51 to 83) there was a significant decrease in serum creatinine from a mean (SD) of 87 (12) μmol/L pretreatment to 84 (12) μmol/L post-treatment (p<0.0001). This difference was more marked in the tertile of patients with the highest baseline creatinine levels. There was also a significant reduction in serum urate from 0.37 (0.07) mmol/L to 0.35 (0.07) mmol/L (p<0.0001). Both these effects were independent of the degree of total cholesterol (TC) or low-density lipoprotein (LDL) cholesterol reduction. There was a significant reduction in TC from 6.6 (1.0) to 5.2 (0.8) mmol/L and LDL cholesterol from 4.3 (1.0) to 2.8 (0.7) mmol/L; both p<0.0001. Significant improvement also occurred in the high-density lipoprotein cholesterol and triglyceride levels. Cholesterol lowering with simvas tatin 20 mg/day improved indices of renal function after 3-4 months of treatment in hyper lipidemic patients with PAD. Further studies are needed to establish and define the clinical relevance of these findings, especially in patients with different degrees of renal failure.

Achieving lipid targets in primary care settings

Achieving low-density lipoprotein cholesterol (LDL-C) goals in clinical practice is still unsatisfactory. Furthermore, a significant residual risk remains, even after reaching LDL-C targets, in terms of both fasting and postprandial triglycerides, high-density lipoprotein cholesterol (quantity and quality) and small dense LDL particles. Statins are the first choice for treating lipid abnormalities. Other lipid-lowering agents can be administered when statins are not tolerated and if LDL-C targets are not reached. Furthermore, multifactorial treatment, including a statin, exerts several beneficial effects on cardiovascular and residual risk reduction. The role of novel developing lipid therapies in clinical practice remains to be established.

Total and low-density lipoprotein cholesterol in high-risk patients treated with atorvastatin monotherapy in the United Kingdom: analysis of a primary-care database

OBJECTIVE

British clinical guidelines recommend statins as first-line lipid-modifying treatment (LMT) for patients at high risk of cardiovascular disease (CVD). We undertook an observational study to assess total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in high-risk patients who were treated with atorvastatin monotherapy by UK general practitioners.

METHODS

This retrospective database study included patients with a prescription for atorvastatin monotherapy between November 30, 2008, and November 30, 2011, with the index date defined as the first atorvastatin prescription during this period. Eligible high-risk patients with evidence of coronary heart disease (CHD), atherosclerotic vascular disease (AVD), diabetes mellitus (DM), or familial hypercholesterolemia (FH) were required to have ≥1 TC and LDL-C measurement between 3 and 12 months after the index date, and continuous enrollment 1 year before and 1 year after the index date. Cholesterol levels were assessed using the National Institute for Health and Care Excellence (NICE) guidelines: TC <4.0 mmol/L or LDL-C <2.0 mmol/L.

RESULTS

Of 2999 high-risk patients (60.2% men; mean [SD] age = 67.9 [10.6] years) meeting selection criteria, 23.9% 28.2%, 36.2%, and 11.6% received prescriptions for atorvastatin 10, 20, 40, and 80 mg, respectively (percentages do not sum to 100 because of rounding). Across all doses, the mean (SD) follow-up TC was 4.08 (0.80) mmol/L and LDL-C 2.08 (0.65) mmol/L. A large proportion of patients (88.8%) had TC < 5.0 mmol/L. However, only 45.8% had TC < 4.0 mmol/L, and 46.5% had LDL-C < 2.0 mmol/L. Although a larger proportion of patients with CHD/AVD + DM reached guideline-recommended lipid levels, only 63.7% of such patients had TC < 4.0 or LDL-C < 2.0 mmol/L, which are the current targets for this subgroup as recommended by NICE.

CONCLUSIONS

Less than half of UK high-CVD-risk patients receiving atorvastatin monotherapy achieved guideline-recommended treatment targets for TC, and less than two-thirds of patients with CHD/AVD + DM had values below TC (4.0 mmol/L) or LDL-C (2.0 mmol/L) targets. More effective lipid-lowering strategies may be warranted to optimize cholesterol lowering and target attainment in high-risk patients. Limitations of this study include its retrospective, observational nature.

Systematic review and meta-analysis of the impact of depression on subsequent smoking cessation in patients with coronary heart disease: 1990 to 2013

OBJECTIVE

Smoking cessation is crucial for patients with coronary heart disease (CHD), yet depression may impede cessation success. We systematically reviewed the prospective association between depression and subsequent smoking cessation in individuals with CHD to quantify this effect.

METHODS

Electronic databases (PsychInfo, PubMed, CINAHL) were searched for prospective studies of patients with CHD that measured depression at baseline (scales, diagnostic interview, or antidepressant prescription) and reported smoking continuation/cessation at follow-up. Inclusive dates were January 1, 1990, to May 22, 2013. Standardized mean differences (SMDs) and associated 95% confidence intervals were estimated using random-effects meta-analysis. Sensitivity analysis explored the impact of limiting meta-analysis to studies using different depression measures (validated scales, diagnostic interviews, antidepressant prescription), different durations of follow-up, or higher-quality studies.

RESULTS

From 1185 citations retrieved, 28 relevant articles were identified. Meta-analysis of all available data from 20 unique data sets found that depressed patients with CHD were significantly less likely to quit smoking at follow-up (SMD = -0.39, 95% confidence interval = -0.50 to -0.29; I(2) = 51.2%, p = .005). Estimates remained largely unchanged for each sensitivity analysis, except for two studies that used antidepressants, which showed a much larger effect (SMD = -0.94, -1.38 to -0.51; I(2) = 57.7%, p = .124).

CONCLUSIONS

Patients with CHD and depressive symptoms are significantly less likely to quit smoking than their nondepressed counterparts. This may have implications for cardiovascular prognosis, and CHD smokers may require aggressive depression treatment to enhance their chances of quitting.

Lifestyle factors, medication use and risk for ischaemic heart disease hospitalisation: a longitudinal population-based study

Background

Lifestyle factors have been implicated in ischaemic heart disease (IHD) development however a limited number of longitudinal studies report results stratified by cardio-protective medication use.

Purpose

This study investigated the influence of self-reported lifestyle factors on hospitalisation for IHD, stratified by blood pressure and/or lipid-lowering therapy.

Methods

A population-based cohort of 14,890 participants aged 45+ years and IHD-free was identified from the Western Australian Health and wellbeing Surveillance System (2004 to 2010 inclusive), and linked with hospital administrative data. Adjusted hazard ratios for future IHD-hospitalisation were estimated using Cox regression.

Results

Current smokers remained at higher risk for IHD-hospitalisation (adjusted HR=1.57; 95% CI: 1.22-2.03) after adjustment for medication use, as did those considered overweight (BMI=25-29 kg/m²; adjusted HR=1.28; 95% CI: 1.04-1.57) or obese (BMI of ≥30kg/m²; adjusted HR=1.31; 95% CI: 1.03-1.66). Weekly leisure-time physical activity (LTPA) of 150 minutes or more and daily intake of 3 or more fruit/vegetable servings reduced risk by 21% (95% CI: 0.64-0.97) and 26% (95% CI: 0.58-0.96) respectively. Benefits of LTPA appeared greatest in those on blood pressure lowering medication (adjusted HR=0.50; 95% CI: 0.31-0.82 [for LTPA<150 mins], adjusted HR=0.64; 95% CI: 0.42-0.96 [for LTPA>=150 mins]). IHD risk in smokers was most pronounced in those taking neither medication (adjusted HR=2.00; 95% CI: 1.41-2.83).

Conclusion

This study confirms the contribution of previously reported lifestyle factors towards IHD hospitalisation, even after adjustment for antihypertensive and lipid-lowering medication use. Medication stratified results suggest that IHD risks related to LTPA and smoking may differ according to medication use.

Effect of tobacco smoking and smoking cessation on plasma lipoproteins and associated major cardiovascular risk factors: a narrative review

Cigarette smoking, active or passive, kills about 6 million people each year worldwide. Cardiovascular disease (CVD) is responsible for 40% of all smoking-related deaths, lung cancer accounts for 20% of all smoking-related deaths, and chronic obstructive pulmonary disease is related to another 20% of deaths. In this narrative review we consider the relationship between cigarette smoking and CVD. We discuss disease states and/or CVD risk factors related to smoking, such as dyslipidaemia, vascular inflammation, endothelial dysfunction, arterial stiffness, insulin resistance, type 2 diabetes mellitus (T2DM), chronic kidney disease (CKD), and non-alcoholic fatty liver disease (NAFLD) as well as their complex interrelations. Smoking cessation can correct abnormalities related to smoking; however, success rates are relatively low. In cases of inability to quit, measures to minimize the adverse effects of smoking specifically related to CVD should be taken. Smokers should receive best practice treatment, according to guidelines, as for non-smokers.

Statins and cardiovascular outcomes in elderly and younger patients with coronary artery disease: a post hoc analysis of the GREACE study

INTRODUCTION

The effect of cardiovascular disease (CVD) prevention measures aimed at elderly patients requires further evidence. We investigated the effect of statin treatment (targeted to achieve guideline goals) on CVD outcomes in different age groups to determine whether statins are more beneficial in the elderly.

MATERIAL AND METHODS

The primary endpoint of this post hoc analysis of the GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) study (n = 1,600 patients with established coronary heart disease (CHD), mean follow-up 3 years) was the absolute and relative CVD event (a composite of death, myocardial infarction, revascularization, unstable angina, heart failure and stroke) risk reduction in age quartiles (each n = 200). Patients on "structured care" with atorvastatin (n = 800) followed up by the university clinic and treated to lipid goal were compared with the corresponding quartiles on "usual care" (n = 800) followed up by specialists or general practitioners of the patient's choice outside the hospital.

RESULTS

In the elderly (mean age 69 ±4 and 70 ±3 years in the "structured" and "usual care", respectively) the absolute CVD event reduction between "structured" and "usual care" was 16.5% (p < 0.0001), while in the younger patients (mean age 51 ±3 years and 52 ±3 years in the "structured" and "usual care", respectively) this was 8.5% (p = 0.016); relative risk reduction (RRR) 60% (p < 0.0001) vs. 42% respectively (p = 0.001). The elderly had higher rates of chronic kidney disease and higher uric acid levels, plus an increased prevalence of diabetes, metabolic syndrome and non-alcoholic fatty liver disease. These factors might contribute to the increased CVD risk in older patients.

CONCLUSIONS

All age groups benefited from statin treatment, but the elderly on "structured care" had a greater absolute and relative CVD risk reduction than the younger patients when compared with the corresponding patients assigned to "usual care". These findings suggest that we should not deprive older patients of CVD prevention treatment and lipid target achievement.

Nurse practitioners, wake up and smell the smoke

PURPOSE

With the focus of modern health care on preventive care, and the well-known benefits of smoking cessation on improving health and reducing healthcare costs, smoking cessation is a key focus of healthcare reform. To change the smoking habits of the U.S. population, two strategies are of particular importance to healthcare professionals: promoting tobacco-free environments in healthcare systems and expanding affordable and effective treatments.

DATA SOURCES

Recent policy literature.

CONCLUSIONS

Barriers to providing smoking cessation counseling most frequently cited by healthcare professionals are lack of training and poor reimbursement; however, recent legislation, for example, the Patient Protection and Affordable Care Act (PPACA), should make preventive services more available and affordable. Nurse practitioners (NPs) have vast experience in addressing health promotion and disease prevention, and are therefore well placed to lead this reform. However, despite consistently higher referrals of tobacco-dependent patients for smoking cessation interventions than any other group of healthcare provider, evidence suggests that NPs are not adequately trained to treat this addiction.

IMPLICATIONS FOR PRACTICE

This article is a call to action for NPs to become familiar with the tobacco cessation policy changes affecting clinical practice, to become experts in tobacco treatment, and to take the lead in this healthcare reform initiative.

Additional Issues on Screening, Prevention, and Treatment of Abdominal Aortic Aneurysms

The prevalence of abdominal aortic aneurysms (AAAs) and AAA-related deaths are steadily declining in some countries as a result of the reduction in smoking rates. It was thus suggested that screening programs that do not target high-risk populations are likely to have very low AAA detection rates. However, this may not apply to other countries that do not exhibit similar reductions in smoking rates. It was assumed that by using the U.S. Preventive Services Task Force screening criteria (men 65-75 years with smoking history) less than 30% of AAAs would be captured. A more extensive scoring system that includes additional risk factors such as the presence of carotid artery or peripheral arterial disease, obesity, hypertension, and so on, may identify almost 90% of AAAs. This article discusses this and other issues on screening, prevention, and treatment of AAAs.

Smoking and Aortic Diseases

Cigarette smoking is a major vascular risk factor and in this context, it is an independent risk factor for the development of aortic disease, especially the formation and growth of abdominal aortic aneurysms (AAA). Medline was searched up to January 31, 2007 for the relevant literature for this review of the mechanisms by which smoking causes aortic wall damage and its subsequent impact on the clinical manifestation of this process. Idiopathic AAAs and aortic dissection are considered, as well as other aortic diseases (eg, Takayasu, Kawasaki, Behcet and Buerger). There is evidence suggesting an abnormal homeostasis between proteolytic and antiproteolytic activity in the vascular wall during the development of AAAs, and these mechanisms can be influenced by smoking. Smoking cessation plays an important role in the management of aortic disease.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Phenotypic predictors of response to simvastatin therapy among African-Americans and Caucasians: the Cholesterol and Pharmacogenetics (CAP) Study

Although statins are effective lipid-lowering agents, the phenotypic and demographic predictors of such lowering have been less well examined. We enrolled 944 African-American and white men and women who completed an open-label, 6-week pharmacogenetics trial of 40 mg of simvastatin. The phenotypic and demographic variables were examined as predictors of the change in lipids and lipoproteins using linear regression analysis. On average, treatment with simvastatin lowered low-density lipoprotein (LDL) cholesterol by 54 mg/dl and increased high-density lipoprotein (HDL) cholesterol by 2 mg/dl. Compared with African-Americans, whites had a 3-mg/dl greater LDL reduction and a 1-mg/dl higher HDL elevation, independent of other variables, including baseline lipoprotein levels (p <0.01). Multivariate analyses revealed moderate subgroup differences, with older participants having a larger decrease in LDL cholesterol and apolipoprotein B levels compared with younger participants (p <0.001), women having larger increases in HDL than men (p <0.01), nonsmokers having larger decreases in LDL and triglyceride levels compared with smokers (p <0.05), those with hypertension having smaller decreases in apolipoprotein B than those without hypertension (p <0.05), and those with a larger waist circumference having a diminished lowering of triglycerides in response to treatment with simvastatin (p <0.01). In conclusion, treatment with simvastatin produced favorable lipid and lipoprotein changes among all participants. The magnitude of the lipid and lipoprotein responses, however, differed among participants according to a number of phenotypic and demographic characteristics.

Influence of smoking on predictors of vascular disease

Beyond the already well-established strong causative relationship with cancer, smoking increases the risk for vascular disease. Smoking may act directly or adversely influence risk factors contributing to the development of vascular disease. Smoking causes endothelial dysfunction, dyslipidemia (decreased high-density lipoprotein cholesterol levels, hypertriglyceridemia and increased oxidation of low-density lipoprotein cholesterol) and platelet activation leading to a prothrombotic state. Smoking increases emerging risk factors (eg, fibrinogen, homocysteine, and high-sensitivity C-reactive protein) and increases insulin resistance and the risk of developing type 2 diabetes mellitus. The beneficial effects of statins and antioxidants (eg, vitamins C and E, beta-carotene) are counteracted by smoking. Smoking-induced alterations in growth factors, adhesion molecules, and even in genes can accelerate the progression of atherosclerosis. The aim of this review is to consider the adverse consequences of smoking on the factors predisposing to vascular disease and to emphasize the beneficial effects of smoking cessation.

Disruption of vascular endothelial homeostasis by tobacco smoke: impact on atherosclerosis

The World Health Organization (WHO) predicts that by 2020 tobacco will become the largest single health problem worldwide and will cause an estimated 8.4 million deaths annually (http://www5.who.int/tobacco/). Although the impact of smoking on human health is well defined from the medical point of view, surprisingly little is known about the mechanisms by which tobacco smoke mediates its disastrous effects. Here, we demonstrate that tobacco smoke dramatically changes vascular endothelial cell and tissue morphology, leading to a loss of endothelial barrier function within minutes. Long-term exposure of endothelial cells to tobacco smoke extracts induces necrosis that may trigger a pro-inflammatory status of the vessel wall. Pre-incubation of the extracts without cells for 6 h at 37 degrees C led to a complete loss of activity. Further, the endothelium could be rescued by changing to fresh medium even at times when the extracts had lost their activity. Finally, we show that N-acetyl cysteine and statins inhibit the adverse tobacco smoke effects.

The epsilon 2 and 4 alleles of apolipoprotein E and ischemic vascular events in the Greek population--implications for the interpretation of similar studies

The authors investigated whether apolipoprotein (apo) E polymorphism has an allelic and/or genotypic impact on the risk of an ischemic vascular event (IVE) in Greek patients with cardiovascular diseases (CVD). They compared apo E polymorphisms in 1) a group of 165 patients with IVE [IVE(+)], of whom 107 had survived a myocardial infarction and 58 an ischemic stroke; 2) a group of 165 patients, matched with the first group for age and gender, with angiographically confirmed coronary artery disease but without IVE [IVE(-)]; 3) a group of 240 healthy younger individuals with no family history of CVD. The apo epsilon2 allele was 5.2-fold less frequent in the IVE(+) group compared to the IVE(-) group (1.2% vs 6.2%, p = 0.001). The frequency of the epsilon2 allele in healthy subjects was 8.1%, which is 6.7-fold higher than in the IVE(+) group (p < 0.001), and more than twice as high compared to all CVD patients (p = 0.001). No significant differences in epsilon4 allele frequencies were observed between IVE(+) and IVE(-) patients (9.8% vs 8.4%) or between patients with CVD and healthy subjects (9.1% vs 10.2%). The epsilon4 allele was not associated with an increased risk for CVD or IVE. In contrast, an inverse and beneficial association of the epsilon2 allele with IVE was observed among Greek patients with CVD. These results suggest that the epsilon4 and epsilon2 alleles have a variable significance in terms of predicting the risk of vascular events in different populations. Therefore, it is important to carry out "local" studies.

Apolipoprotein E polymorphism and atherosclerosis

The relationship between apolipoprotein (apo) E and vascular disease has been the subject of a considerable amount of research. However, this relationship is far from clearly defined. This deficiency appears to be due to a multitude of factors. Among these are differences in ethnicity, age (and possibly gender), diagnostic criteria, and environmental factors (eg, diet and smoking) that have contributed to the contradictory findings. Several diseases and their treatment may also influence this relationship. There are also documented interactions between apo E genotypes and other genes or vascular risk factors. One possible clinically relevant application of identifying the apo E genotype could be to assess the response to a particular drug treatment. It may also be that apo E polymorphism will become a good predictor of vascular death (eg, from myocardial infarction or stroke) rather than an indicator of the risk of developing vascular disease but without an acute ischemic event. More research is required to define the place of apo E genotyping in the management of vascular disease in its various forms. Whatever the future brings, the evaluation of apo E genotypes will need to be rapid, cheap, and technically undemanding before this investigation becomes widely available and clinically relevant.

Statins and renal function

Renal disease is often associated with an increased risk of vascular events. Moreover, an accelerated form of atherosclerosis commonly occurs in these patients. The reasons for these associations are not clearly defined but include the widespread presence of several established risk factors (eg, dyslipidemia, hypertension, and diabetes). Other predictors of atherosclerotic disease may also be abnormally elevated (eg, homocysteine, fibrinogen, and lipoprotein a). In addition, there is evidence that impaired renal function per se predicts vascular risk. Despite this high-risk background, the potential benefit of treatment with statins has not been widely investigated in these patients. The present review considers the evidence (experimental and clinical) that statins exert beneficial effects in patients with different types of renal disease. This includes improved renal function, decreased microalbuminuria, and a fall in blood pressure. Statins may also improve renal allograft survival. The potential mechanisms mediating these effects are considered. The interactions between statins and several risk factors that may be present in patients with impaired renal function are also considered. There is an urgent need to define the role of statins in these high-risk patients. Which is the statin of choice? This question is relevant because impaired renal function can interfere with statin pharmacokinetics. Furthermore, other drugs administered to these patients may cause serious interactions with statins.

The early effect of lipid-lowering treatment on carotid and femoral intima media thickness (IMT)

OBJECTIVES

an increased intima media thickness (IMT) is an early indicator of the atherosclerotic process. We investigated the early effect of atorvastatin on the common carotid artery (CCA) and common femoral artery (CFA) IMT.

METHODS

the IMT was measured in the CCA and the CFA of hyperlipidaemic patients referred with peripheral vascular disease. The measurements were performed using an automated radio frequency IMT technique pre-treatment and at 4 and 8 weeks post-treatment with 20 mg/day atorvastatin.

RESULTS

patients (14 men; 11 women), median age 69 years (range: 48-81) had a CCA-IMT mean (SD) of 0.79 (0.21) mm pre-treatment, 0.75 (0.22) mm after 4 weeks, and 0.64 (0.15) mm after 8 weeks. The ANOVA test was significant (p=0.024) for the CCA-IMT trend. The corresponding CFA-IMT readings were 0.83 (0.13) mm, 0.80 (0.09) mm and 0.69 (0.14) mm (p=0.0003). After 8 weeks of treatment there was a significant reduction in total cholesterol 6.0 (0.3) to 4.3 (0.8) mmol/l, p=0.0004 and low-density lipoprotein cholesterol 3.7 (0.2) to 2.2 (0.5), p=0.0001. There was a significant decrease in median serum creatinine levels after 8 weeks treatment: 87 micromol/l (range 67-114) to 84 micromol/l (range: 64-112), p=0.007.

CONCLUSIONS

cholesterol-lowering with atorvastatin 20 mg/day leads to a decrease in CCA-IMT and CFA-IMT. This difference achieved significance after 8 weeks of treatment, but a trend was visible at 4 weeks. These rapid changes in IMT may be attributable to an anti-inflammatory effect. IMT measurement may be a useful tool to rapidly assess the effect of drug treatment on the atherosclerotic process.

Are high-density lipoprotein and triglyceride levels important in secondary prevention: impressions from the BIP and VA-HIT trials

Two major trials, the Bezafibrate Infarction Prevention Trial (BIP) and the Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial (VA-HIT) were conducted to clarify the contribution of correcting diminished high density lipoprotein (HDL) (and lowering triglyceride, TG) levels to the risk of cardiovascular events in patients with coronary heart disease (CHD). In BIP, bezafibrate did not significantly reduce the risk of CHD. In contrast, in VA-HIT, gemfibrozil significantly reduced the risk of CHD (22% reduction in primary end point, P=0.006). These trials differ in several respects making direct comparisons difficult. For example, the placebo arm in VA-HIT had a greater prevalence of primary events than that in BIP (22 vs. 15%). The baseline mean LDL value in BIP was also higher compared to that in VA-HIT (148 vs. 112 mg/dl; 3.82 vs. 2.89 mmol/l). Other trials (e.g., AFCAPS and LIPID) showed that patients with LDL values similar to those in BIP benefited significantly from treatment with statins. Therefore, the BIP population may have been more effectively treated with a statin. In contrast, in VA-HIT the LDL level was close to those recommended in the USA and the UK for secondary prevention (100 and 115 mg/dl; 2.6 and 3.0 mmol/l, respectively). Guidelines emphasise that the LDL level is the main treatment target. However, BIP and VA-HIT suggest that correcting HDL and TG levels may be beneficial especially when the LDL level has reached the target value. We may have become too focused on LDL levels and the use of statins.

The role of platelets in peripheral arterial disease: therapeutic implications

Peripheral arterial disease (PAD) is associated with platelet hyperaggregability as well as an increase in morbidity and mortality from myocardial infarction and stroke. Enhanced platelet activation in PAD may substantially contribute to these adverse outcomes. A relative resistance to aspirin therapy has been reported in patients with PAD. Therefore, clopidogrel may be superior to aspirin in treatment of PAD. Furthermore, the aspirin + clopidogrel combination could be more effective than monotherapy but its risk-benefit ratio has yet to be evaluated. Clopidogrel is preferable to ticlopidine because of its safer profile and the convenience of once-daily administration. The glycoprotein (Gp) IIb/IIIa inhibitors may also find a place as short-term therapy after peripheral angioplasty. There is a need to consider the use of clopidogrel in patients who cannot tolerate aspirin. Patients who have an event while taking aspirin also present a problem. One possibility here is to substitute aspirin with clopidogrel or to add clopidogrel to the aspirin. Although these options are currently not evidence based in patients with PAD, there is emerging evidence showing that they are realistic choices.