Effects of statins on carotid disease and stroke

The results of recent trials indicate that statin treatment reduces not only the risk of coronary heart disease, but also the risk of stroke, in patients with existing heart disease. The need for the treatment of such patients is now generally recognized. Mechanisms for risk reduction include the retardation of plaque progression, plaque stabilization, and reducing the risk of coronary events. Questions remain regarding the discrepancy between epidemiological data and statin trials data, the precise mechanism of action of statins, and their role in the prevention of recurrent stroke in individuals who have experienced a previous stroke or transient ischemic attack but are free of coronary disease.     

Plasma desmoplakin I biomarker of vascular recurrence after ischemic stroke

Stroke patients have a high risk of vascular recurrence. Biomarkers related to vascular recurrence, however, remain to be identified. The aim of the study was to identify, through proteomic analysis, plasma biomarkers associated with vascular recurrence within one year after the first ischemic stroke. This is a substudy (n = 134) of a large prospective multicenter study of post-stroke patients with an ischemic stroke. Plasma samples were obtained at inclusion. Among the identified proteins, only plasma levels of desmoplakin I were associated with protection against a new vascular event (Odds ratio: 0.64; 95% CI: 0.46-0.89; p = 0.009) after adjustment for hypercholesterolemia, statins and previous atherothrombotic stroke subtype. A greater number of patients without vascular recurrence had been treated with statins within three months of the recent ischemic stroke. Only patients who had been taking statins for 3 months after the ischemic stroke and did not suffer vascular recurrence over a follow-up year, have higher levels of desmoplakin I at the time of inclusion (Odds ratio 0.49; 95% CI: 0.28-0.86; p = 0.013). Increased desmoplakin I levels, determined within 1-3 months of the first ischemic stroke, could be a biomarker for statin responsiveness against a new vascular event in post-ischemic stroke patients taking statins early (1-3 months) after the ischemic stroke.     

Effect of statins in stroke prevention

PURPOSE OF REVIEW: This paper reviews recent studies into the outcomes of clinical trials in which statin therapy has been used in the prevention and treatment of strokes. RECENT DEVELOPMENTS: Epidemiologic studies found no or little association between blood cholesterol levels and stroke. Randomized trials have confirmed that LDL lowering decreased the risk of stroke, in diabetic or hypertensive patients with 'normal' LDL cholesterol at baseline, and in patients with coronary artery disease, with respectively 48, 27 and 25% reduction in stroke incidence. A meta-analysis of trials showed that the greater the LDL cholesterol reduction, the greater the intima-media thickness and stroke risk reductions. Even if statins also have 'pleiotropic' effects, their main action seems to be through LDL reduction. The Heart Protection Study only included strokes that occurred 4.6 years before--a time when the stroke event rate is low and the cardiac event rate is high, and so may not have had the power to find a true effect of LDL cholesterol lowering in preventing recurrent stroke. The Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL) trial may give a definite answer because SPARCL investigators included 4732 patients with brain infarction or transient ischemic attacks and no history of myocardial infarction within 6 months of their stroke event, at a time when the expected stroke rate is very high and the myocardial infarction rate is very low. The results should be announced by mid-2006. SUMMARY: The positive effect of statins on stroke observed in trials of patients with coronary heart disease depended mainly on between-group LDL reduction, but other mechanisms could be involved. Though effective in prevention of major coronary events after a first stroke, statins have not yet been proven effective in prevention of recurrent stroke.     

Statin therapy and stroke prevention: what was known, what is new and what is next?

PURPOSE OF REVIEW: Randomized trials have shown that statins may reduce the risk of primary stroke. There is no evidence however that statins can reduce recurrent stroke incidence. RECENT FINDINGS: In the SPARCL trial, patients with a recent stroke or transient ischemic attack randomized to atorvastatin 80 mg/day had a significant 16% relative risk reduction of stroke, and a 35% reduction in major coronary events compared with placebo. This was obtained despite 25% of the placebo arm patients receiving a commercially-available statin outside of the trial. Post-hoc analysis used blinded LDL-cholesterol measurements as a marker of adherence to lipid-lowering therapy. Compared with the group with no change or an increase in LDL-cholesterol (the group adherent to placebo or not taking a statin), the group with over 50% reduction in LDL-cholesterol had a significant 31% reduction in stroke. The next step is to define whether achieving LDL-cholesterol below 70 mg/dl is better than a standard dose of statin (LDL around 100-110 mg/dl) in the secondary prevention of stroke. SUMMARY: Statins are effective in reducing both first-ever and recurrent stroke, and this effect seems driven by the extent of LDL-cholesterol lowering.     

Statins and Neuroprotection: Basic Pharmacology Needed

Statins are attracting great interest albeit with some controversy in treating certain neurodegenerative diseases such as Alzheimer disease, Parkinson disease, multiple sclerosis, ischemic stroke, and traumatic brain injury. Support for the use of statins has come from human studies and animal and cell models. Despite the intense level of interest, there is a deficiency in information on the basic pharmacokinetics and pharmacodynamics of statins in the brain. The purpose of this focused review is to examine what is known and the gaps in our knowledge on detectability of statin lactones and acids in the brain, membrane partitioning and active transport of statins across the blood–brain barrier, and statin effects on brain isoprenoid levels. Statins may be efficacious in treating certain neurodegenerative diseases. Having basic information on statin pharmacokinetics and pharmacodynamics in the brain would provide insight into specific drug targets and also provide the rationale for optimizing statins in terms of enhancing brain influx and inhibiting efflux.     

Statins – Do we really know all mechanisms of action of this group of drugs?

The role of statins in the treatment and prevention of cardiovascular diseases, such as coronary artery disease, acute coronary syndromes, diabetes or stroke is well established. However, there are still many questions regarding the role of statins in patients with heart failure (HF)/cardiomyopathy (CM), hypertension, atrial fibrillation (AF) and chronic kidney disease (CKD). As for patients with HF/CM inhibition of inflammation, reducing endothelial dysfunction might comprise part of the underlying mechanisms leading to the improvement of left ventricular function and exercise tolerance in these groups of patients. Therefore the candidates for statin therapy with HF/CM should be in New York Heart Association class II or III and should have normal or increased levels of lipids. We should avoid reducing lipids levels in these patients. At present, it is also difficult to unequivocally assess the impact of statins on blood pressure (BP). However, according to most available studies, the impact of statins on the decrease in BP is slight, but significant, especially among patients with hypertension. Moreover statins significantly reduce cardiovascular events in patients with hypertension. Although the results of trials concerning the use of statins in CKD patients are conflicting, it is suggested that the benefits of statin use outweigh the drawbacks in patients with early-stage CKD, when the benefits can be effectively predicted. However, available large randomized clinical trials suggest a lack of efficacy in patients on renal replacement therapy. We also needs further data on the role of statins on AF, however the existing studies suggest beneficial impact of statins in these patients.     

Update for primary healthcare providers: recent statin trials and revised National Cholesterol Education Program III guidelines

Statins produce large, clinically important beneficial effects on total low-density lipoprotein (LDL) cholesterol and triglycerides while raising high-density lipoprotein (HDL) cholesterol--each of which increases the risks for cardiovascular disease (CVD). In randomized trials of secondary and primary prevention, and their meta-analyses, statins confer statistically significant, clinically important reductions in myocardial infarction, stroke, and CVD death. In 2001, the National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III included LDL as the primary target, recommending optional goals of < 100 mg/dL for high-risk patients, < 130 mg/dL for moderate-risk patients, and < 160 mg/dL for low-risk patients. We conducted a search of randomized trials of statins whose results were published since May 15, 2001. We extracted overall trial results and data on adverse events, when available. We reviewed 7 published trials of statins, some of which contributed to the recent addendum to the NCEP ATP III guidelines that recommend reducing LDL goals to < 70 for very high-risk and < 100 for moderately high-risk patients via statins. Data from these trials demonstrate that greater LDL reductions produce larger CVD benefits in various categories of high- and moderate-risk patients, including a large number of primary prevention patients with metabolic syndrome who should be treated as aggressively as patients who have survived a myocardial infarction or stroke. Together, these recent statin trials and the NCEP ATP III revised guidelines, if implemented by primary healthcare providers, would result in many more patients receiving statins of proven benefit and reassuring adverse event profile.     

缺血性脑卒中二级预防研究进展

脑卒中是一种危害人类健康的全球性问题。缺血性脑卒中复发是此类疾病患者面临的最严重问题之一,而且复发后会进一步加重患者功能障碍,甚至导致死亡。二级预防的主要目的是阻止短暂性脑缺血发作后发生的脑卒中或首次脑卒中后再发的脑卒中。所以,首次卒中后尽早开展二级预防显得尤为重要。下面,我们就有关缺血性脑卒中二级预防的控制危险因素、抗栓治疗、手术治疗、及生活习惯改变等方面,将近年来研究的新进展进行总结。     

Anticoagulation for the Acute Management of Ischemic Stroke

Few prospective studies support the use of anticoagulation during the acute phase of ischemic stroke, though observational data suggest a role in certain populations. Depending on the mechanism of stroke, systemic anticoagulation may prevent recurrent cerebral infarction, but concomitantly carries a risk of hemorrhagic transformation. In this article, we describe a case where anticoagulation shows promise for ischemic stroke and review the evidence that has discredited its use in some circumstances while showing its potential in others.     

大动脉粥样硬化型缺血性脑血管病的颅内外血管搭桥治疗（附48例分析）

目的：评价大动脉粥样硬4E（Large．arteryatherosclerosis,LA）型缺血性脑血管病颅内外血管搭桥术（EC—ICbypass）的治疗效果,探讨颅内外血管搭桥术在新的历史条件下对于LA型缺血性脑血管病治疗的有效性。方法：回顾性分析48例LA型缺血性脑血管病病人的临床资料,其中短暂性脑缺血发作（TIA）36例,语言功能障碍8例,单侧肢体轻瘫4例。根据临床症状结合术前影像学资料,行颅内外血管搭桥术治疗。根据术后临床症状改善情况,并对比手术前后影像学资料的变化,对颅内外血管搭桥术治疗效果进行评价。结果：TLA病人中,1例术后出现卒中事件,其余35例术后TIA症状消失;语言功能障碍和单侧肢体轻瘫病人术后半年症状均有改善;40例LA型缺血性脑血管病病人术后影像学复查均获满意效果。结论：颅内外血管搭桥术对于LA型缺血性脑血管病的预防和治疗是有效的。     

阿司匹林对骨髓间充质干细胞移植治疗缺血性脑卒中的影响研究进展

阿司匹林是缺血性脑卒中患者急性期治疗药物及卒中再发的二级预防常用药物,骨髓间充质干细胞(BMSCs)移植是治疗缺血性脑血管疾病的新的新兴技术。已证实阿司匹林可抑制骨髓间充质干细胞的增殖及影响骨髓间充质干细胞的分化。本文就阿司匹林对骨髓间充质干细胞移植治疗缺血性脑卒中的影响等进行综述。     

Clinical implications for statin pleiotropy

PURPOSE OF REVIEW: Atherosclerosis is a multi-factorial condition involving dyslipidemia that can result in cardiovascular disease. Statins are potent inhibitors of cholesterol biosynthesis, and in clinical trials, statins have been shown to be beneficial in the primary and secondary prevention of coronary heart disease. However, the overall benefits observed with statins appear to occur much earlier and to be greater than what might be expected from changes in lipid levels alone, suggesting effects beyond cholesterol lowering. SUMMARY OF FINDINGS: Recent studies indicate that some of the cholesterol-independent or 'pleiotropic' effects of statins involve improving endothelial function, enhancing the stability of atherosclerotic plaques, decreasing oxidative stress and inflammation, and inhibiting the thrombogenic response. Many of these pleiotropic effects are mediated by inhibition of isoprenoids, which serve as lipid attachments for intracellular signaling molecules. In particular, inhibition of small GTP-binding proteins, Rho, Ras, and Rac, whose proper membrane localization and function are dependent upon isoprenylation, may play an important role in mediating the pleiotropic effects of statins. SUMMARY: The potential clinical implications of statin pleiotropy suggests that perhaps other biomarkers, in addition to lipid levels, should be used to gauge the full efficacy of statin therapy in patients with cardiovascular risks or that statin therapy may be effective in disease states, such as inflammatory conditions, ischemic stroke or cancer, where elevated cholesterol levels have not been shown to be a strong epidemiological risk for these diseases.     

Statins enhance clonal growth of late outgrowth endothelial progenitors and increase myocardial capillary density in the chronically ischemic heart

Background

Coronary artery disease and ischemic heart disease are leading causes of heart failure and death. Reduced blood flow to heart tissue leads to decreased heart function and symptoms of heart failure. Therapies to improve heart function in chronic coronary artery disease are important to identify. HMG-CoA reductase inhibitors (statins) are an important therapy for prevention of coronary artery disease, but also have non-cholesterol lowering effects. Our prior work showed that pravastatin improves contractile function in the chronically ischemic heart in pigs. Endothelial progenitor cells are a potential source of new blood vessels in ischemic tissues. While statins are known to increase the number of early outgrowth endothelial progenitor cells, their effects on late outgrowth endothelial progenitor cells (LOEPCs) and capillary density in ischemic heart tissue are not known. We hypothesized that statins exert positive effects on the mobilization and growth of late outgrowth EPCs, and capillary density in ischemic heart tissue.

Methodology/Principal Findings

We determined the effects of statins on the mobilization and growth of late outgrowth endothelial progenitor cells from pigs. We also determined the density of capillaries in myocardial tissue in pigs with chronic myocardial ischemia with or without treatment with pravastatin. Pravastatin therapy resulted in greater than two-fold increase in CD31+ LOEPCs versus untreated animals. Addition of pravastatin or simvastatin to blood mononuclear cells increased the number of LOEPCs greater than three fold in culture. Finally, in animals with chronic myocardial ischemia, pravastatin increased capillary density 46%.

Conclusions

Statins promote the derivation, mobilization, and clonal growth of LOEPCs. Pravastatin therapy in vivo increases myocardial capillary density in chronically ischemic myocardium, providing an in vivo correlate for the effects of statins on LOEPC growth in vitro. Our findings provide evidence that statin therapy can increase the density of capillaries in the chronically ischemic heart.     

Effect of pre-stroke use of ACE inhibitors on ischemic stroke severity

Background  

Recent trials suggest that angiotensin-converting enzyme inhibitors (ACEI) are effective in prevention of ischemic stroke, as measured by reduced stroke incidence. We aimed to compare stroke severity between stroke patients who were taking ACEI before their stroke onset and those who were not, to examine the effects of pretreatment with ACEI on ischemic stroke severity.     

微栓子监测及其在缺血性脑血管病中的应用研究进展

微栓子监测技术(Microemboli monitoring technology,MMT)是20世纪90年代发展起来的一项新技术。1990年,Spencer等定义了微栓子信号(Micro embolus signal,MES)。1992年,Russell等明确提出了微栓子监测的概念,并结合实验数据,对微栓子的监测进行了初步总结。1995年,第九届国际脑血流动力学会议确定了MES的判断标准。近年来,微栓子监测技术已经广泛应用于心脏、血管外科和神经科领域,并取得了一些进展。目前,不仅在理论上证实了应用TCD技术监测微栓子的可行性,而且大量的临床观察表明这项技术可以为研究缺血性脑血管病的发生机制、治疗效果、预后判断及疾病预防提供客观的依据。本文将对下述问题进行综述:微栓子监测在缺血性脑血管病研究中的应用(颈源性、颅内动脉源性、心源性、其他病因所导致的缺血性脑血管病);微栓子监测对缺血性脑血管病药物治疗疗效的评估;微栓子监测对卒中复发的预计;以及微栓子监测对临床缺血性脑血管病溶栓治疗的监测。综述近年来微栓子监测在临床缺血性脑血管病诊治预防中取得的新进展、面临的问题以及新的发展。     

Statin diabetogenicity: guidance for clinicians

Type 2 diabetes (T2D) is a strong, independent risk factor for cardiovascular (CV) and cerebrovascular outcomes. Meta-analysis of five randomised clinical trials (n = 33,040) showed that, although intensive versus standard glycaemic control significantly reduced CV events in people with T2D, the reduction was less than that achieved with lipid-lowering or antihypertensive treatment. Furthermore, fasting plasma glucose (FPG) concentrations were a modest predictor for CV risk in people without T2D. Thus, although effective glycaemic control is important for the prevention/management of T2D, other risk factors must be addressed to effectively reduce CV risk. Reducing low-density lipoprotein-cholesterol levels using statins significantly reduces CV risk in people with and without T2D. Although statins are generally safe and well tolerated, conflicting data exist regarding the diabetogenic effects of some statins. Based on recent clinical trial data, the US Food and Drug Administration have changed the labelling of all statins to include ‘an effect of statins on incident diabetes and increases in haemoglobin A1c and/or FPG’. However, the literature suggests that the beneficial effects of most statins on CV risk continue to outweigh their diabetogenic risks and that statins should remain as first-line therapy for the majority of people with dyslipidaemia and metabolic syndrome or T2D. Mechanisms explaining the potentially higher incidence of T2D with statin therapy have not been confirmed. However, independent predictors for statin-associated T2D appear to include elevated levels of baseline FPG, BMI, blood pressure and fasting triglycerides. Moreover, although some statins (for example, atorvastatin) are associated with increased haemoglobin A1c levels in patients receiving intensive but not moderate therapy, other statins (for example, pitavastatin) have demonstrated neutral or favourable effects on glucose control in patients with and without T2D or metabolic syndrome. The potential diabetogenic effects of statins may therefore differ between drugs. In conclusion, conflicting data exist regarding the diabetogenic effects of statins. Further studies are required to understand whether all statins have the same effect and whether some patient groups are at higher risk than others. Meanwhile, results suggest that the net CV benefit favours the use of statin therapy in patients with dyslipidaemia, irrespective of T2D risk.     

中药活性成分改善缺血缺氧所致脑微血管内皮 屏障功能损伤的研究进展

缺血性脑卒中发生时,基质金属蛋白酶等效应分子以及炎症反应、氧化应激等会破坏血脑屏障,增加缺血区有害产物进入脑组织, 产生脑水肿,引起继发性脑损伤。所以,保护与维持脑微血管内皮屏障功能的完整性,是脑卒中防治的重要策略之一。从调节效应分子 和相关信号通路的角度出发,综述中药活性成分对模拟缺血性脑卒中的体内外脑微血管内皮屏障功能损伤模型的改善作用研究进展,以 期为进一步阐释中药活性成分防治缺血性脑卒中的作用机制以及新药创制提供参考和依据。     

Anticoagulation after Anterior Myocardial Infarction and the Risk of Stroke

Background

Survivors of anterior MI are at increased risk for stroke with predilection to form ventricular thrombus. Commonly patients are discharged on dual antiplatelet therapy. Given the frequency of early coronary reperfusion and risk of bleeding, it remains uncertain whether anticoagulation offers additional utility. We examined the effectiveness of anticoagulation therapy for the prevention of stroke after anterior MI.

Methods and Findings

We performed a population-based cohort analysis of 10,383 patients who survived hospitalization for an acute MI in Ontario, Canada from April 1, 1999 to March 31, 2001. The primary outcome was four-year ischemic stroke rates compared between anterior and non-anterior MI patients. Risk factors for stroke were assessed by multivariate Cox proportional-hazards analysis. Warfarin use was determined at discharge and followed for 90 days among a subset of patients aged 66 and older (n = 1483). Among the 10,383 patients studied, 2,942 patients survived hospitalization for an anterior MI and 20% were discharged on anticoagulation therapy. Within 4 years, 169 patients (5.7%) were admitted with an ischemic stroke, half of which occurred within 1-year post-MI. There was no significant difference in stroke rate between anterior and non-anterior MI patients. The use of warfarin up to 90 days was not associated with stroke protection after anterior MI (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.37–1.26). The use of angiotensin-converting-enzyme inhibitors (HR, 0.65; 95% CI, 0.44–0.95) and beta-blockers (HR, 0.60; 95% CI, 0.41–0.87) were associated with a significant decrease in stroke risk. There was no significant difference in bleeding-related hospitalizations in patients who used warfarin for up to 90 days post-MI.

Conclusion

Many practitioners still consider a large anterior-wall MI as high risk for potential LV thrombus formation and stroke. Among a cohort of elderly patients who survived an anterior MI there was no benefit from the use of warfarin up to 90 days post-MI to prevent ischemic stroke. Our data suggests that routine anticoagulation of patients with anterior-wall MI may not be indicated. Prospective randomized trials are needed to determine the optimal antithrombin strategy for preventing this common and serious adverse outcome.     

Protecting the heart: a practical review of the statin studies

The aim of this review of the landmark HMG-CoA reductase inhibitors (statins) studies is to enable the clinician to draw practical lessons from these trials. The Scandinavian Simvastatin Survival Study (4S) established the importance of treating the hypercholesterolemic patient with established cardiovascular heart disease. The West of Scotland Coronary Prevention Study (WOSCOPS) showed the benefit of treating healthy hypercholesterolemic men who were nevertheless at high risk of developing cardiovascular heart disease in the future. The Cholesterol and Recurrent Events (CARE) study, a secondary prevention trial, proved the benefit of treating patients with myocardial ischemia and cholesterol levels within normal limits. This conclusion was confirmed by the Long-term Intervention With Pravastatin in Ischemic Disease (LIPID) study, another secondary prevention study that enrolled patients with a wide range of cholesterol levels (4-7 mmol/dL), into which the large majority of patients would belong. The importance of treating patients with established ischemic heart disease (IHD), and those at high risk of developing cardiovascular heart disease, regardless of cholesterol level, was being realized. The Air Force/Texas Coronary Artery Prevention Study (AFCAPS/TexCAPS) then showed that treatment can reduce adverse cardiovascular events even in the primary prevention of patients with normal cholesterol levels. The Myocardial Ischemia Reduction With Aggressive Cholesterol Lowering (MIRACL) trial showed that hypocholesterolemic therapy is useful in the setting of an acute coronary syndrome, while the Atorvastatin Versus Revascularisation Treatment (AVERT) study showed that aggressive statin therapy is as good as angioplasty in reducing ischemic cardiac events in patients with stable angina pectoris. Finally, the Heart Protection Study (HPS) randomized more than 20,000 patients, and the value of statins in reducing adverse cardiovascular events in the high-risk patient, including the elderly, women, and even in those with low cholesterol levels, is beyond doubt. The emphasis is now on the risk level for developing cardiovascular events, and treatment should target the high-risk group and not be dependent on the actual cholesterol level of the patient. It is interesting to compare the large amount of data on the value and safety of the statins with the much more limited and less convincing data on antioxidant vitamins.     

缺血性脑卒中患者脑内微出血的发生及危险因素

目的:探讨脑内微出血(CMB)在缺血性脑卒中患者中的发生及相关危险因素。方法:连续选取住院的缺血性脑卒中患者250例,分析其磁共振成像(MRI)表现。根据有无CMB将患者分为CMB组(80例)及无CMB组(170例)。详细记录临床资料,观察CMB的个数、陈旧性腔隙性脑梗死的个数和脑白质改变(WMC)的严重程度。结果:单因素分析显示年龄、高血压病、既往脑梗死病史、脑白质改变、陈旧性腔隙性脑梗死及口服抗血小板聚集药物史与CMB的发生有关。Logistic回归分析显示高血压、既往有脑梗死病史及WMC分值为CMB的独立危险因素。结论:CMB与脑微血管病变之间有密切关系,高血压、既往有脑梗死病史及WMC分值为缺血性脑卒中患者发生CMB的独立危险因素。