Pravastatin therapy and the risk of stroke

Evolving treatment strategies for carotid artery stenosis

Internal carotid artery stenosis is an important cause of ischemic stroke. Treatment decisions frequently center on whether the patient is symptomatic or asymptomatic. For recently symptomatic patients with severe stenosis (70% to 99%) and low to medium surgical risk, carotid endarterectomy (CEA) is extremely useful for stroke prevention. CEA is moderately useful for patients with 50% to 69% symptomatic stenosis and is not indicated for patients with symptomatic stenosis of less than 50%. CEA may be useful for select patients with severe asymptomatic stenosis (80% to 99%) but only if the surgical complication is kept below the 3% level. Carotid stenting is an emerging option for the future but is still experimental. In addition to carotid intervention, patients with carotid stenosis should receive aggressive risk factor management, including treatment with antiplatelet agents and statins.

Preventing the next event in the elderly: the PROSPER perspective

Statins reduce coronary and cerebrovascular morbidity and mortality in middle-aged individuals but their efficacy and safety in elderly people has not been confirmed. Several clinical trials including the Cholesterol and Recurrent Events (CARE) and Long-term Intervention with Pravastatin in Ischemic Disease (LIPID), have sub-analysed their results for the 'elderly' cohort, but the Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) trial is the first trial to specifically evaluate the benefits of statin therapy on vascular risk in elderly men and women. The results have shown that pravastatin, given for 3 years, reduced the risk of coronary heart disease in elderly individuals. Within this same time frame, there was no significant benefit on the risk reduction of stroke but there was a trend to reduce the risk of transient ischemic attacks. It was discovered that those patients with the lowest baseline high-density lipoprotein cholesterol gained the most benefit from the intervention. Drug interactions between pravastatin and the concomitant medications seen in this elderly cohort, was not a significant clinical issue. Therefore, PROSPER extends to elderly individuals the treatment strategy currently used in middle-aged people.

Effects of cholesterol-lowering with simvastatin on stroke and other major vascular events in 20536 people with cerebrovascular disease or other high-risk conditions

BACKGROUND

Lower blood cholesterol concentrations have consistently been found to be strongly associated with lower risks of coronary disease but not with lower risks of stroke. Despite this observation, previous randomised trials had indicated that cholesterol-lowering statin therapy reduces the risk of stroke, but large-scale prospective confirmation has been needed.

METHODS

3280 adults with cerebrovascular disease, and an additional 17256 with other occlusive arterial disease or diabetes, were randomly allocated 40 mg simvastatin daily or matching placebo. Subgroup analyses were prespecified of first "major vascular event" (ie, non-fatal myocardial infarction or coronary death, stroke of any type, or any revascularisation procedure) in prior disease subcategories. Subsidiary outcomes included any stroke, and stroke sub-type. Comparisons are of all simvastatin-allocated versus all placebo-allocated participants (ie, "intention-to-treat"), which yielded an average difference in LDL cholesterol of 1.0 mmol/L (39 mg/dL) during the 5-year treatment period.

FINDINGS

Overall, there was a highly significant 25% (95% CI 15-34) proportional reduction in the first event rate for stroke (444 [4.3%] simvastatin vs 585 [5.7%] placebo; p<0.0001), reflecting a definite 28% (19-37) reduction in presumed ischaemic strokes (p<0.0001) and no apparent difference in strokes attributed to haemorrhage (51 [0.5%] vs 53 [0.5%]; rate ratio 0.95 [0.65-1.40]; p=0.8). In addition, simvastatin reduced the numbers having transient cerebral ischaemic attacks alone (2.0% vs 2.4%; p=0.02) or requiring carotid endarterectomy or angioplasty (0.4% vs 0.8%; p=0.0003). The reduction in stroke was not significant during the first year, but was already significant (p=0.0004) by the end of the second year. Among patients with pre-existing cerebrovascular disease there was no apparent reduction in the stroke rate, but there was a highly significant 20% (8-29) reduction in the rate of any major vascular event (406 [24.7%] vs 488 [29.8%]; p=0.001). The proportional reductions in stroke were about one-quarter in each of the other subcategories of participant studied, including: those with coronary disease or diabetes; those aged under or over 70 years at entry; and those presenting with different levels of blood pressure or lipids (even when the pretreatment LDL cholesterol was below 3.0 mmol/L [116 mg/dL]).

INTERPRETATION

Much larger numbers of people in the present study suffered a stroke than in any previous cholesterol-lowering trial. The results demonstrate that statin therapy rapidly reduces the incidence not only of coronary events but also of ischaemic strokes, with no apparent effect on cerebral haemorrhage, even among individuals who do not have high cholesterol concentrations. Allocation to 40 mg simvastatin daily reduced the rate of ischaemic strokes by about one-quarter and so, after making allowance for non-compliance in the trial, actual use of this regimen would probably reduce the stroke rate by about a third. HPS also provides definitive evidence that statin therapy is beneficial for people with pre-existing cerebrovascular disease, even if they do not already have manifest coronary disease.

Early benefit from structured care with atorvastatin in patients with coronary heart disease and diabetes mellitus

This is a prospective evaluation of the effect of structured care of dyslipidemia with atorvastatin (strict implementation of guidelines) versus usual care (physician's standard of care) on morbidity and mortality of patients with coronary heart disease (CHD) and diabetes mellitus (DM). From 1600 consecutive CHD patients randomized to either form of care in the GREek Atorvastatin and CHD Evaluation Study (GREACE), 313 had DM: 161 in the structured care arm and 152 in the usual care arm. All patients were followed up for a mean of 3 years. In the structured care group, patients were treated with atorvastatin to achieve the National Cholesterol Education Program (NCEP) low-density lipoprotein cholesterol (LDL-C) treatment goal of <2.6 mmol/L (100 mg/dL). Primary endpoints were all-cause and coronary mortality, coronary morbidity, and stroke. In the structured care group, 156 patients (97%) were taking atorvastatin (10-80 mg/day; mean, 23.7 mg/day) throughout the study; the NCEP LDL-C treatment goal was reached by 150 patients (93%). Only 17% (n=26) of the usual care patients were on long-term hypolipidemic drug treatment and 4% (n=6) reached the NCEP LDL-C treatment goal. During the study, 46 of 152 (30.3%) CHD patients with DM on usual care experienced a major vascular event or died versus 20 of 161 (12.5%) patients on structured care; relative risk reduction (RRR) 58%, p<0.0001. RRR for all-cause mortality was 52%, p=0.049; coronary mortality 62%, p=0.042; coronary morbidity 59%, p<0.002; and stroke 68%, p=0.046. Event rate curves started deviating from the sixth treatment month and the RRR was almost 60% by the 12th month. RRRs remained at that level until the end of the study, when they became statistically significant. The cost/life-year gained with structured care was estimated at 6200 US dollars. In CHD patients with DM, structured care of dyslipidemia with atorvastatin to achieve the NCEP LDL-C treatment goal, reduces all-cause and coronary mortality, coronary morbidity, and stroke by more than one half within a 3-year period, in comparison to usual care. Clinical benefit is manifested as early as the sixth month of treatment.

Risk for stroke after elective noncarotid vascular surgery

INTRODUCTION

Patients undergoing operations to treat peripheral vascular disease have systemic atherosclerosis and are at risk for stroke. However, the incidence and effect of cerebrovascular events on noncarotid vascular surgical outcomes are not well-defined.

METHODS

Patients undergoing common operations for vascular disease from 1997 to 2000 were examined with data from the Veterans Affairs (VA) National Surgery Quality Improvement Project and the VA patient treatment files. Operations studied included abdominal aortic aneurysmectomy (n = 2551), aortobifemoral bypass (n = 2616), lower extremity bypass (n = 6866), and major lower extremity amputation (n = 7442). The incidence of perioperative stroke was determined, and logistic regression analysis was used to identify independent risk factors for stroke. Logistic and linear regression analyses were used to quantify the effect of postoperative stroke on adjusted mortality and length of stay. Odds ratio (OR) and 95% confidence interval (CI) were defined. P <.05 was considered significant.

RESULTS

Stroke was uncommon after noncarotid vascular procedures, occurring in only 0.4% to 0.6% of patients. Independent risk factors for stroke include preoperative ventilation (OR, 11; 95% CI, 5.0-22.3; P <.001), previous stroke or transient ischemic attack (OR, 4.2; 95% CI, 2.7-6.4; P <.001), postoperative myocardial infarction (OR, 3.3; 95% CI, 1.3-8.7; P =.009), and need to return to the operating room (OR, 2.2; 95% CI, 1.4-3.5; P =.001). Factors that did not appear to be associated with stroke risk included procedure type, diabetes, renal failure, dialysis dependence, number of transfused units of blood, and hypertension. After controlling for other postoperative complications and comorbid conditions, postoperative stroke significantly increased the risk for perioperative mortality (OR, 6.3; 95% CI, 3.4-11.4; P <.001), with similar magnitude as postoperative myocardial infarction (OR, 6.3; 95% CI, 3.9-10.1; P <.001). Stroke was also associated with a 48% increase in overall length of stay.

CONCLUSIONS

Stroke after noncarotid peripheral vascular surgery is uncommon, but results in markedly increased mortality and length of stay. Stroke risk is most strongly associated with previous stroke history and greater degree of illness. Patients with these associated conditions deserve particular attention to assessing and medically managing modifiable risk factors.

Strategies to Increase HMG-CoA Reductase Inhibitor Use After Acute Myocardial Infarction

Coronary artery disease with its accompanying complication of acute myocardial infarction (MI) is one of the major causes of death in the modern world. A variety of both primary and secondary prevention strategies have been developed for the treatment of acute MI. One of the more important of these strategies is the prescription of HMG-CoA reductase inhibitors. HMG-CoA reductase inhibitors have the potential to positively affect the outcome of acute MI in a variety of ways including the reduction of low-density lipoprotein-cholesterol levels and stabilisation of the atherosclerotic plaque. Multiple large randomised clinical trials have documented the potential of HMG-CoA reductase inhibitors to reduce both short- and long-term mortality after acute MI. This benefit exists regardless of age, gender, clinical presentation, or even baseline lipid levels. However, despite this overwhelming amount of evidence supporting the use of HMG-CoA reductase inhibitors in the post-MI setting, multiple studies have documented the presence of a significant 'treatment gap'. Indeed, often, less than half of acute MI patients who would benefit from HMG-CoA reductase inhibitor therapy actually receive it. The reasons for the low utilisation of HMG-CoA reductase inhibitors in the acute MI patient are many, but may include poor communication, the high cost of treatment, the lack of associated symptoms and confusion regarding appropriate lipid levels to target. One approach that has been tried to address these issues is the development of institutional programmes specifically targeted to increase the use of HMG-CoA reductase inhibitors in acute MI patients. These programmes, often managed by nurses or pharmacists, have been piloted in several institutions. They have been effectively implemented in both inpatient and outpatient settings. In most cases they have been implemented without a great increase in expense. They have often increased the use of HMG-CoA reductase inhibitors to >90%. Most importantly, they have documented a significant improvement in the long-term survival of acute MI patients. Based on these preliminary studies, it is recommended that the implementation of these strategies be considered by most healthcare institutions.

Statins and Stroke Prevention

Four randomized trials with a statin and one trial with a fibrate showed a modest but significant absolute reduction in the incidence of stroke in patients with a previous myocardial infarction. The reasons for the positive effect of statins on stroke end-point are unclear since, paradoxically, the link between serum cholesterol level and stroke has never been fully established. Furthermore, the positive results of statins trials were mainly obtained in patients with an average or a low serum cholesterol level. This suggests nonhypolipidemic effects of these drugs, so-called pleiotropic effects, acting on the biologic promoters of plaque instability. Statins have a good overall safety profile with no increase of hemorrhagic stroke and no increase in cancer. They have positive effects in primary prevention of cardiovascular disease in high-risk young as well as elderly populations. Statins reduced stroke incidence in high-risk (mainly CHD, diabetics and hypertensives) population even with a normal baseline blood cholesterol level, which argues for a global cardiovascular risk-based treatment strategy. In patients with prior strokes, statins likely reduce the incidence of cononary events, but it is not yet proven that statins actually reduce the incidence of recurrent strokes in secondary prevention. If current hypotheses are verified by ongoing trials, we may expect between 20 to 30 more stroke events avoided per 1,000 patients treated during 2 years with a lipid-lowering agent, which adds to the 28 stroke events prevented with an antiplatelet agent over the same time period. This would be one of the most significant advances in stroke and vascular dementia prevention since the era of aspirin therapy.

Cholesterol and the risk of ischemic stroke

BACKGROUND AND PURPOSE

Large epidemiological studies have not established cholesterol levels as a risk factor for ischemic stroke, but recent clinical trials have demonstrated a reduction in the ischemic stroke rate for patients taking HMG-CoA reductase inhibitors ("statins"). The goal of this study was to evaluate whether total cholesterol (TC), high-density lipoprotein (HDL), triglycerides, and the TC:HDL ratio are risk factors for ischemic stroke in apparently healthy men enrolled in the Physicians' Health Study.

METHODS

We used a nested case-control study design and matched 296 ischemic stroke cases with an equal number of controls on age, tobacco use, and follow-up time. At baseline, TC, HDL, and triglyceride levels were measured. We calculated odds ratios (ORs) and their 95% confidence intervals (CIs) using conditional logistic regression, adjusting for major risk factors for ischemic stroke.

RESULTS

Compared with the reference lowest quartile, the highest quartile for TC had an adjusted OR of 1.56 (95% CI, 0.84 to 2.92), the highest quartile of HDL had an adjusted OR of 0.75 (95% CI, 0.43 to 1.30), and the highest quartile of triglycerides had an adjusted OR of 1.07 (95% CI, 0.63 to 1.82). Although the highest quartile of the TC:HDL ratio had an adjusted OR of 1.62 (95% CI, 0.93 to 2.82), the risk of ischemic stroke was not a linear relationship.

CONCLUSIONS

After adjustment, TC, HDL, and triglycerides were not significantly associated with ischemic stroke risk, and for the TC:HDL ratio, a suggestion of increased risk of ischemic stroke was limited to those with the highest levels.

Role of transesophageal echocardiography in the evaluation of patients with stroke

This review article summarizes recent advances in the care of patients presenting with neurologic events, in which transesophageal echocardiography plays an important role in diagnosis, prognosis, and treatment. New research on the use of transesophageal echocardiography in patients with stroke and atrial fibrillation is discussed, including left atrial clot formation, maintenance of sinus rhythm after cardioversion, and techniques of left atrial appendage occlusion. A discussion of developments in the diagnosis and management of thoracic aortic plaque follows. The association of patent foramen ovale and atrial septal aneurysm with stroke is outlined, and possible reasons for this association are discussed. Recent literature on the use of percutaneous closure devices for patent foramen ovale is reviewed.

Clinical trials: Evidence and unanswered questions--hyperlipidaemia

It is now clear that the management of hypercholesterolaemia is important for the reduction of morbidity and mortality caused by cerebrovascular and coronary events. The landmark Scandinavian Simvastatin Survival Study was the first to show conclusively that lipid-lowering therapy with statins reduces the incidence of stroke. Subsequent trials, undertaken in a variety of different patient populations, have confirmed that statin therapy reduces the incidence of stroke by approximately one-third. This important benefit has been observed in men and women, the young and the elderly, and also in subjects with diabetes mellitus. In the recent Heart Protection Study, which recruited "high-risk" vascular subjects, stroke risk reduction was demonstrated even among those subjects considered to have "low" low-density lipoprotein (LDL) cholesterol levels. The benefits of statin therapy in stroke have been attributed to reductions in cholesterol and to other non-lipid-lowering effects of statins. Ongoing clinical trials such as TNT (Treating to New Targets) and IDEAL (Incremental Decrease in Endpoints through Aggressive Lipid lowering) will test the "lower is better" hypothesis. Using statins to lower LDL cholesterol to levels that are below current guidelines will provide additional benefits in stroke risk reduction. Most of the data on cholesterol reduction and cerebrovascular events have been derived from studies of patients with documented coronary heart disease (CHD). The ongoing SPARCL (Stroke Prevention by Aggressive Reduction in Cholesterol Levels) trial will examine the benefits of LDL cholesterol lowering in patients with previous stroke or transient ischaemic attack (TIA), but no history of coronary problems.

Potential nontraditional applications of statins

OBJECTIVE

To review the current evidence for use of hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) in nontraditional lipid-related applications, including acute coronary syndromes, peripheral arterial disease, stroke, and renal disease, and to describe ongoing trials evaluating the role of statins in these conditions.

DATA SOURCES

Clinical literature was identified by a MEDLINE search (1990-November 2002) using >/=1 of the following search terms: acute coronary syndrome(s), angina pectoris, atherosclerosis, atorvastatin, clinical trials, diabetes mellitus, end-stage renal disease, fluvastatin, lovastatin, myocardial infarction, peripheral arterial disease, pravastatin, simvastatin, statins, and stroke. Treatment guidelines issued by professional and governmental organizations, such as the American Diabetes Association, American Heart Association, National Cholesterol Education Program, National Kidney Foundation, and National Stroke Foundation, were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Articles identified from the data sources were included if they pertained to the conditions described in the objectives and provided unique information concerning use of statins.

DATA SYNTHESIS

Substantial evidence exists for the use of statins in acute coronary syndromes. Meta-analyses of data from major clinical trials indicate that statins prevent first and recurrent stroke, and large-scale trials are underway to evaluate the efficacy of statins in this setting. Accumulating evidence suggests that statins may be beneficial in reducing the morbidity and mortality associated with peripheral arterial disease and end-stage renal disease, and results from ongoing trials may confirm these benefits. Statins may also have a future role in amelioration of other conditions associated with atherosclerosis, such as diabetes mellitus.

CONCLUSIONS

A large body of evidence supports the evaluation of statins in clinical settings beyond primary and secondary prevention of morbidity and mortality associated with coronary atherosclerosis.

Cerebrovascular cases

Five cases are presented illustrating some of the investigative and therapeutic dilemmas faced when treating patients with cerebrovascular disease in the outpatient clinic. The results of some recent major randomized controlled trials are applied to assist the decision-making process for individual patients. The investigation and management of patients with minor stroke or transient ischemic attack, and symptomatic or asymptomatic carotid stenosis are discussed. Issues raised include the role of angiography versus noninvasive imaging, carotid endarterectomy versus carotid stenting, and how to apply new evidence regarding antihypertensive and lipid-lowering therapy to patient management. The role of thrombolysis for acute stroke is discussed, and the work-up of a patient with attacks of dizziness and a patient with atypical headache are also presented.

Study of Heart and Renal Protection (SHARP)

Among patients with preexisting coronary heart disease, large-scale randomized trials have demonstrated that lowering low-density lipoprotein (LDL)-cholesterol concentration by about 1 mmol/L for 4-5 years reduces the risk of coronary events and strokes by about 25%. Patients with established chronic kidney disease (CKD) are at high risk of vascular disease, so the benefits of cholesterol-lowering therapy might be expected to be substantial in this population. Patients with CKD have generally been excluded from previous trials, however, and there is currently no reliable randomized evidence that lowering LDL-cholesterol would be beneficial among them. There are several reasons why the demonstrated benefits of lowering blood cholesterol in other populations might not translate to patients with CKD. First, observational studies among dialysis patients have reported a negative association between blood total cholesterol and mortality. Second, only about one quarter of cardiac mortality in such patients appears to be attributable to acute myocardial infarction, and potentially avoidable with cholesterol lowering, while the other common causes (e.g., cardiac arrest, arrhythmia, and heart failure) may not be as dependent on cholesterol levels. Finally, the long-term safety of cholesterol reduction among patients with CKD remains unclear. Hence, there is an important need for reliable direct evidence on whether lowering cholesterol prevents a worthwhile proportion of vascular events, without unacceptable toxicity, among patients with CKD. The Study of Heart and Renal Protection (SHARP) aims to assess the effects of cholesterol-lowering therapy with a combination of simvastatin and the cholesterol-absorption inhibitor ezetimide among around 9000 patients with CKD.

Drug therapy of neurovascular disease

Recent advances in the prevention and pharmacotherapy of cerebrovascular disease have provided more favorable clinical outcomes. For the treatment of an acute ischemic stroke, the early use of thrombolytic agents can reduce the degree of brain damage while improving functional outcomes. However, trials evaluating various classes of other neuroprotective agents have not shown benefit to date. For the prevention of second stroke, the use of antiplatelet drugs, HMG-CoA reductase inhibitors, and angiotensin-converting enzyme inhibitors with a diuretic have shown benefit in reducing new events. In patients with underlying heart disease or atrial fibrillation, warfarin appears to be the drug of choice in preventing stroke. Early treatment of hemorrhagic stroke with calcium channel blockers can improve the functional outcome. Innovative therapies are now available for the treatment of migraine and vascular dementia. Primary prevention of stroke remains the optimal therapeutic strategy and includes treatment of systemic hypertension and hypercholesterolemia.

The pleiotropic effects of HMG-CoA reductase inhibitors: their role in osteoporosis and dementia

HMG-CoA reductase is the rate-limiting enzyme for cholesterol synthesis and its inhibition exerts profound effects on cellular metabolism. Inhibitors of this enzyme are used in clinical practice to lower plasma cholesterol levels and are commonly collectively referred to as 'statins'. A number of in vitro, in vivo animal, and clinical studies suggest that properties of statins other than cholesterol lowering may be of biological importance. These diverse properties are often referred to as 'pleiotropic' and suggest that statins may affect a number of diseases of ageing. In this article we review the biological plausibility and clinical evidence of a role for statins in modulating two diseases of ageing: osteoporosis and dementia (including Alzheimer's disease). In both diseases, there is a sound cellular and laboratory basis for a plausible therapeutic effect of statins. In the case of osteoporosis, there are conflicting data regarding clinical benefit, with both negative and positive results reported. In particular, secondary analyses of randomised, controlled studies have shown no reduction of fracture risk by statins. In the case of dementia there are fewer clinical studies but there is clear anticipated benefit in macrovascular dementias attributable to statin-mediated reduction of the risk of stroke. Overall, there are a lack of prospective, placebo-controlled, randomised data testing statins and modulation of the risk of osteoporosis-related fracture or of clinical dementia, where these are primary outcomes. Until such data are available, the use of statins appears promising but cannot be recommended as a primary therapeutic modality for either condition.

A benefit-risk assessment of agents used in the secondary prevention of stroke

Stroke is a major cause of morbidity and mortality. Full assessment of stroke or transient ischaemic attack (TIA) patients is required to identify all risk factors and apply appropriate secondary preventative strategies. Antiplatelet therapies are effective in the secondary prevention of ischaemic stroke and can be justified despite adverse effects such as gastrointestinal haemorrhage. Aspirin (acetylsalicylic acid), aspirin plus dipyridamole, ticlopidine and clopidogrel are all of value but their adverse effect profiles vary significantly. Combinations of antiplatelet agents may offer additional benefit but not all combinations have been studied in stroke patients. Anticoagulation with agents such as warfarin is effective with coexisting atrial fibrillation and other conditions predisposing to cardioembolic stroke. Antihypertensive agents have been extensively studied in the primary prevention of stroke; however, relatively few trials of antihypertensive agents in the secondary prevention of stroke are available. The incidence of adverse effects of antihypertensive agents is relatively low and the benefit-risk profile would tend to favour their use in the secondary prevention of stroke. Recent studies of ACE inhibitors have identified an important role for these agents in the secondary prevention of stroke even in those who are normotensive and in those who have had a haemorrhagic stroke. The incidence of serious adverse effects with ACE inhibitors appears relatively low. Lipid-lowering agents may have a role to play in certain groups of patients with stroke. The incidence of adverse effects is relatively low with HMG-CoA reductase inhibitors. Cigarette smoking is an important risk factor for stroke and evidence is available that smoking cessation does reduce the individual's risk of stroke. Pharmacological agents are available to help smoking cessation. In patients with diabetes mellitus, intensive regimens with insulin and oral hypoglycaemic agents have so far not definitively been shown to reduce the incidence of macrovascular complications such as stroke. Tight glycaemic control has been shown to improve microvascular complications such as retinopathy, nephropathy and neuropathy and hence this is reason enough to advocate the use of these agents. Future developments in the treatment of diabetes may help. Secondary prevention of stroke has improved greatly over the past decade and hopefully will continue to improve. The use of pharmacological agents available currently and in the future will be clarified and refined as further clinical trials report.

Medical prevention of stroke, 2003

Stroke is a preventable tragedy for nearly 750,000 people each year. Primary stroke prevention measures applicable to the general public include a healthy diet containing fruits, vegetables, fish, and low fat; exercise; smoking cessation; limiting alcohol to moderate use; and perhaps avoidance of stress. Screening for hypertension, cholesterol, heart disease, and carotid artery stenosiscan lead to even more effective stroke prevention in high-risk patients. Specific antihypertensive drugs such as angiotensin-converting enzyme inhibitors and angiotensin-converting enzyme receptor blockers may be especially protective against stroke. Secondary stroke prevention in patients who have already had a stroke or transient ischemic attack is even more effective in preventing more serious strokes. Measures include antihypertensive and cholesterol-lowering agents, carotid endarterectomy, anticoagulation for atrial fibrillation and other cardiac sources of embolic stroke, and antiplatelet therapy. Stroke prevention depends on the application of these well-known and widely available treatments to a large number of patients.

Stroke prevention: what's new?

Abstract Antithrombotic treatment has now been joined by other evidence-based drug interventions for prevention of stroke, including angiotensin-converting enzyme inhibitors and hydroxymethylglutaryl-CoA reductase inhibitors. The efficacy of oral anticoagulation in atrial fibrillation has not been seen in other stroke-prone groups, although trials are continuing. Diffusion-weighted magnetic resonance imaging improves diagnostic accuracy in acute stroke, which is important in arriving at the right secondary prevention strategy. Carotid endarterectomy has been shown to be beneficial for 50-69% symptomatic -stenosis but with a much narrower therapeutic index than for 70-99% stenosis. A comparison of endarterectomy with angioplasty and/or stent placement has been the subject of one small trial suggesting similar procedural stroke and mortality risks. Device closure of cardiac abnormalities increases in the absence of any trial data, and in spite of a low subsequent stroke risk for young patients with isolated patent foramen ovale treated with aspirin.

Benefits of aggressive drug therapy

Significant advances have been made in both the development and implementation of drug therapy in the primary and secondary prevention of cardiovascular disease. Defining "aggressive" drug therapy mandates consideration of the target population, timing of initiation, time of administration, and, often, dose titration to achieve a desired effect on relevant "biomarkers" such as low-density lipoprotein levels. This review focuses on 2 groups of drug therapies now proven effective in prevention, namely the statins and antiplatelet drugs (aspirin, clopidogrel). Angiotensin-converting enzyme inhibitor(s), angiotensin receptor blockers, and beta blockers are also proven of great value but are only noted in the table.

Cerebrovascular disease in Italy and Europe: it is necessary to prevent a 'pandemia'

In Italy and Europe, strokes are the third most common cause of death and resulting invalidity. In the ever-increasing 80-years-old-and-over population, strokes become more serious due to the clinical presentation during the acute phase and the ten times higher mortality, but also in relation to the twice as high resulting disability as for younger subjects. With the growing number of ailing and not-self-sufficient elderly, other resources will have to be relocated to this field of public health. Then, the dependence index and the ensuing equivalence based on estimates for the first decades of 2000 will create more difficulties in retrieving the funds for social policies. However, stroke prevention is possible both through correct behavioural habits and pharmacological means. Besides the well-known preventive effects of an adequate antihypertensive, antidiabetic and/or antiaggregant/anticoagulant therapy, there is increasing evidence of the effectiveness of statin therapy in stroke prevention. Subjects with a personal history of cerebrovascular events have an increased coronary risk and vice versa. The greatest part of the risk factors for the cerebrovascular disease coincides with those for cardiovascular disease, for which the correction of the former automatically involves a reduction in incidence of both pathologies. In this context, a statin's rational use can therefore represent an important tool for the combined prevention of the two pathologies. Finally, different hypotheses link the origin of Alzheimer's disease to that of progressive cerebrovascular dementia caused by cerebral microcirculation damage. The aim of this review is to resume the actual knowledge about the epidemiology of cerebrovascular disease in Italy and Europe, and about the means available to prevent this phenomenon.

Prevention of stroke and dementia with statins: Effects beyond lipid lowering

Stroke is a major cause of mortality and morbidity. The epidemiologic association between elevated serum cholesterol and stroke risk is controversial. However, recent secondary prevention studies with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have demonstrated a significant reduction in ischemic stroke without an increase in hemorrhagic stroke. Statins probably reduce stroke by a variety of mechanisms, including modulation of precerebral atherothrombosis in the aorta and the carotid artery, thus preventing plaque disruption and artery-to-artery thromboembolism. Statins also improve endothelial homeostasis by increasing the bioavailability of nitric oxide, which orchestrates the paracrine antiatherosclerotic functions of the endothelium. Studies in experimental models of ischemic stroke show that statin therapy reduces brain infarct size and improves neurologic outcome by directly upregulating brain endothelial nitric oxide synthase. Putative anti-inflammatory actions of statins may also contribute to neuroprotection and stroke prevention. Although the clinical benefit of statins largely depends on lowering low-density lipoprotein cholesterol, accumulating data indicate that many of the pleiotropic effects of statins are attributable to the cellular consequences of depletion of intermediates in the cholesterol biosynthetic pathway (isoprenoids). These molecules play fundamental roles in cell growth, signal transduction, and mitogenesis. In addition to reducing stroke risk, emerging data suggest that statins may reduce dementia. Further studies are needed to fully address the role of statins in the prevention of stroke in patients without established vascular disease and the role of cholesterol modulation in the treatment of dementia.

Patient selection for carotid endarterectomy: how far is risk modeling applicable to the individual?

BACKGROUND AND PURPOSE

Risk-factor modeling has been proposed to identify patients with carotid stenosis who will most benefit from surgery. Validation by independent institutions performing carotid endarterectomy is necessary to determine the applicability of such models to the individual patient.

METHODS

A series of patients with a recently symptomatic high-grade carotid stenosis were selected for surgery according to current guidelines and were consecutively operated on in a single institution. In addition, a prognostic model was applied to the patients to analyze the concordance of both selection methods.

RESULTS

The study included 134 patients operated on between 1999 and 2001. The risk model predicted that 49% of the patients should have been excluded from surgery because the operation was found to be possibly harmful in 1 patient (1%) and not significantly beneficial in 65 patients (48%). This resulted from the predominant negative weight of the surgical risk factors in the model. However, this predominance was negated in our series by the fact that only 1 major complication (0.75%) occurred during follow-up.

CONCLUSIONS

Exclusion of single patients on the basis of risk modeling may be problematic when the rate of perioperative complications is very low.

Are cholesterol-lowering medications and antihypertensive agents preventing stroke in ways other than by controlling the risk factor?

Statins and angiotensin-converting enzyme (ACE) inhibitors are an important component of our armamentarium for stroke prevention. Both of these classes of agents have a primary mechanism of action of reducing the level of the respective risk factor. They also have mechanisms of action that may confer benefits beyond what is believed to be the primary action of the agent. This has led to speculation that statins reduce stroke risk by means beyond cholesterol lowering, and ACE inhibitors reduce stroke risk by means beyond blood pressure lowering. We review the mounting evidence that suggests that statins and ACE inhibitors have so-called pleiotropic effects that may lead to stroke prevention.

Women do benefit from lipid lowering: latest clinical trial data

Cardiovascular disease is the leading cause of morbidity and mortality among women in industrialized nations. Optimizing cardiovascular risk reduction is therefore of paramount importance, particularly among postmenopausal women, in whom the incidence of cardiovascular disease is highest. Accumulated data from a series of landmark trials unequivocally demonstrate the efficacy of statin therapy in the primary and secondary prevention of cardiovascular outcomes in both men and women. Moreover, the recently released Heart Protection Study provides substantive evidence that lowering low-density lipoprotein cholesterol below levels currently defined as optimal by National Cholesterol Educational Program guidelines is strongly associated with further cardiovascular risk reduction, and that this benefit accrues in all subgroups of patients, including women and the elderly. Despite the ability of hormone replacement therapy to improve serum lipid profiles, randomized trials of hormone therapy have demonstrated no benefit in reducing coronary outcomes among postmenopausal women. In contrast, data from over 8,000 women enrolled in the statin trials demonstrate that lipid lowering with statins is as effective at reducing cardiovascular outcomes in women as it is in men and suggest that statins should be considered standard of care for the prevention of adverse cardiovascular events in women at risk for coronary heart disease.

Are cholesterol-lowering medications and antihypertensive agents preventing stroke in ways other than by controlling the risk factor?

Statins and angiotensin-converting enzyme (ACE) inhibitors are an important component of our armamentarium for stroke prevention. Both of these classes of agents have a primary mechanism of action of reducing the level of the respective risk factor. They also have mechanisms of action that may confer benefits beyond what is believed to be the primary action of the agent. This has led to speculation that statins reduce stroke risk by means beyond cholesterol lowering, and ACE inhibitors reduce stroke risk by means beyond blood pressure lowering. We review the mounting evidence that suggests that statins and ACE inhibitors have so-called pleiotropic effects that may lead to stroke prevention.

Effect of treatment on the incidence of stroke and other emboli in 519 patients with severe thoracic aortic plaque

Severe aortic plaques seen on transesophageal echocardiography (TEE) are a high-risk cause of stroke and peripheral embolization. Evidence to guide therapy is lacking. Retrospective information was obtained regarding the occurrence of embolic events (stroke, transient ischemic attacks, or peripheral emboli) in 519 patients with severe thoracic aortic plaque seen on TEE since 1988. Treatment with statins, warfarin, or antiplatelet medications was noted. Treatment was not randomized. In a matched-paired analysis, each patient taking each class of therapy was matched for age, gender, previous embolic event, hypertension, diabetes, congestive failure, and atrial fibrillation to someone not taking that medication. Multivariate analysis was also performed. An embolic event occurred in 111 patients (21%). Multivariate analysis showed that statin use was independently protective against recurrent events (p = 0.0001). Matched analysis also showed a protective effect of statins (p = 0.0004; absolute risk reduction 17%, relative risk reduction 59%, number needed to treat [n = 6]). No protective effect was found for warfarin or antiplatelet drugs. The odds ratio for embolic events was 0.3 (95% confidence interval [CI] 0.2 to 0.6) for statin therapy, 0.7 (95% CI 0.4 to 1.2) for warfarin, and 1.4 (95% CI 0.8 to 2.4) for antiplatelet agents. Thus, there is a protective effect of statin therapy, and no significant benefit of warfarin or antiplatelet drugs on the incidence of stroke and other embolic events in patients with severe thoracic aortic plaque on TEE.

Risk factors for non-haemorrhagic stroke in patients with coronary heart disease and the effect of lipid-modifying therapy with pravastatin

OBJECTIVE

To determine the relative importance of recognised risk factors for non-haemorrhagic stroke, including serum cholesterol and the effect of cholesterol-lowering therapy, on the occurrence of non-haemorrhagic stroke in patients enrolled in the LIPID (Long-term Intervention with Pravastatin in Ischaemic Disease) study.

DESIGN

The LIPID study was a placebo-controlled, double-blind trial of the efficacy on coronary heart disease mortality of pravastatin therapy over 6 years in 9014 patients with previous acute coronary syndromes and baseline total cholesterol of 4-7 mmol/l. Following identification of patients who had suffered non-haemorrhagic stroke, a pre-specified secondary end point, multivariate Cox regression was used to determine risk in the total population. Time-to-event analysis was used to determine the effect of pravastatin therapy on the rate of non-haemorrhagic stroke.

RESULTS

There were 388 non-haemorrhagic strokes in 350 patients. Factors conferring risk of future non-haemorrhagic stroke were age, atrial fibrillation, prior stroke, diabetes, hypertension, systolic blood pressure, cigarette smoking, body mass index, male sex and creatinine clearance. Baseline lipids did not predict non-haemorrhagic stroke. Treatment with pravastatin reduced non-haemorrhagic stroke by 23% (P = 0.016) when considered alone, and 21% (P = 0.024) after adjustment for other risk factors.

CONCLUSIONS

The study confirmed the variety of risk factors for non-haemorrhagic stroke. From the risk predictors, a simple prognostic index was created for non-haemorrhagic stroke to identify a group of patients at high risk. Treatment with pravastatin resulted in significant additional benefit after allowance for risk factors.

Role of lipid-modifying therapy in the prevention of initial and recurrent stroke

PURPOSE OF REVIEW

To establish the role of cholesterol-modifying therapy in stroke prevention.

RECENT FINDINGS

Population-based observational cohort studies show a variable weak positive relationship between increasing plasma total cholesterol concentrations and an increasing risk of ischaemic stroke, which is partly offset by a weaker negative association between decreasing total cholesterol concentrations and an increasing risk of with haemorrhagic stroke. However, randomized controlled trials show unequivocally that lowering plasma total cholesterol by approximately 1.2 mmol/l (and LDL-cholesterol by 1.0 mmol/l) is associated with a reduced relative risk of stroke and other serious vascular events by at least a quarter, and probably a third, without any increase in haemorrhagic stroke, in a wide range of men and women (including individuals with previous stroke). The proportional reduction in stroke risk is consistent, irrespective of the patient's age, baseline plasma cholesterol concentration, and absolute risk of stroke (although perhaps less in very low-risk individuals), but is increased with greater degrees of cholesterol lowering (15% or more), and thus with statin medications, which are more potent than non-statin interventions in lowering cholesterol levels. The absolute reduction in stroke risk achieved by statins is greatest among individuals at highest risk of stroke. Preliminary evidence suggests that lowering total cholesterol levels by diet may be an effective adjunctive therapy to statins, and raising plasma HDL-cholesterol concentrations among patients with coronary heart disease and low HDL-cholesterol levels ( 1 mmol/l) by means of gemfibrozil may also effectively prevent stroke.

SUMMARY

Statin drugs are effective and safe in preventing initial and recurrent stroke. However, because they are costly, they should probably be restricted to individuals with an annual risk of stroke and other serious vascular events of 3% or greater, and possibly as low as 1.5%, because routine monitoring of plasma cholesterol, and liver and muscle enzyme concentrations is probably no longer necessary.

Carotid stenosis: medical and surgical aspects

Medical treatment for carotid disease is similar to the treatment of atherosclerosis, with some recent data suggesting that there is a benefit to an aspirin-dipyridamole combination. CEA has revolutionized the treatment of symptomatic and asymptomatic carotid stenosis. This approach remains the gold standard for the surgical treatment of carotid artery stenosis, against which emerging modalities such as percutaneous carotid stenting should be compared. Higher-risk, asymptomatic patients can safely undergo CEA in high-volume centers for stenosis greater than 80% as defined by ultrasound.

Effects of atorvastatin on stroke in patients with unstable angina or non-Q-wave myocardial infarction: a Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL) substudy

BACKGROUND

This report describes the effect of intensive cholesterol lowering with atorvastatin on the incidence of nonfatal stroke, a secondary end point, in a randomized, placebo-controlled trial of patients with unstable angina or non-Q-wave myocardial infarction. The primary end point, a composite of death, nonfatal myocardial infarction, resuscitated cardiac arrest, or recurrent symptomatic myocardial ischemia with objective evidence requiring emergency rehospitalization, was reduced from 17.4% in the placebo group to 14.8% in the atorvastatin group over the 16 weeks of the trial (P=0.048).

METHODS AND RESULTS

Strokes were adjudicated by a blinded end-point committee using standard clinical and imaging criteria. The outcomes of nonfatal stroke and fatal plus nonfatal stroke were analyzed by time to first occurrence during the 16-week trial. Of 38 events (in 36 patients) adjudicated as fatal or nonfatal strokes, 3 were classified as hemorrhagic, one as embolic, and 29 as thrombotic or embolic; 5 could not be categorized. Nonfatal stroke occurred in 9 patients in the atorvastatin group and 22 in the placebo group (relative risk, 0.40; 95% confidence intervals, 0.19 to 0.88; P=0.02). Fatal or nonfatal stroke occurred in 12 atorvastatin patients and 24 placebo patients (relative risk, 0.49; 95% confidence intervals, 0.24 to 0.98; P=0.04). All 3 hemorrhagic strokes occurred in the placebo group.

CONCLUSION

Intensive cholesterol lowering with atorvastatin over 16 weeks in patients with acute coronary syndromes reduced the overall stroke rate by half and did not cause hemorrhagic stroke. These findings need to be confirmed in future trials.

Prevention of Ischemic Stroke

The primary risk factors for stroke are known, and attention to primary care of these disorders should reduce the incidence of stroke significantly. Control of hypertension, diabetes, and hyperlipidemia have all been shown to reduce the rate of stroke. Identification of potential cardioembolic sources of stroke, particularly atrial fibrillation, can prevent stroke with appropriate application of anticoagulation. Duplex Doppler B-mode sonography can establish the extent of carotid artery disease in patients with cervical bruit or risk factors for atherosclerosis, and indicate which conditions should be managed medically or surgically. Patients with a history suggestive of transient ischemic attacks can also be screened noninvasively with duplex sonography to determine if they have a critical carotid stenosis and require carotid endarterectomy. New advances in platelet antiaggregant therapy with ticlopidine, clopidogrel, and the combination of aspirin with dipyridamole have also reduced the rate of stroke to a greater degree than standard treatment with aspirin. The incidence of this devastating illness could possibly be reduced by 50% with attentive primary care management. The cardiologist is often involved in the treatment of patients at risk for stroke, and is in an ideal position to provide this care.

Antithrombotic Secondary Prevention After Stroke

In patients with transient ischemic attack (TIA) or ischemic stroke of noncardiac origin, antiplatelet drugs are able to decrease the risk of stroke by 11% to 15%, and decrease the risk of stroke, myocardial infarction (MI), and vascular death by 15% to 22%. Aspirin leads to a moderate but significant reduction of stroke, MI, and vascular death in patients with TIA and ischemic stroke. Low doses are as effective as high doses, but are better tolerated in terms of gastrointestinal side effects. The recommended aspirin dose, therefore, is between 50 and 325 mg. Bleeding complications are not dose-dependent, and also occur with the lowest doses. The combination of aspirin (25 mg twice daily) with slow-release dipyridamole (200 mg twice daily) is superior compared with aspirin alone for stroke prevention. Ticlopidine is effective in secondary stroke prevention in patients with TIA and stroke. For some end points, it is superior to aspirin. Due to its side-effect profile (neutropenia, thrombotic thrombocytopenic purpura ), ticlopidine should be given to patients who are intolerant of aspirin. Prospective trials have not indicated whether ticlopidine is suggested for patients who have recurrent cerebrovascular events while on aspirin. Clopidogrel has a better safety profile than ticlopidine. Although not investigated in patients with TIA, clopidogrel should also be effective in these patients assuming the same pathophysiology than in patients with stroke. Clopidogrel is second-line treatment in patients intolerant for aspirin, and first-line treatment for patients with stroke and peripheral arterial disease or MI. A frequent clinical problem is patients who are already on aspirin because of coronary heart disease or a prior cerebral ischemic event, and then suffer a first or recurrent TIA or stroke. No single clinical trial has investigated this problem. Therefore, recommendations are not evidence-based. Possible strategies include the following: continue aspirin, add dipyridamole, add clopidogrel, switch to ticlopidine or clopidogrel, or switch to anticoagulation with an International Normalized Ratio (INR) of 2.0 to 3.0. The combination of low-dose warfarin and aspirin was never studied in the secondary prevention of stroke. In patients with a cardiac source of embolism, anticoagulation is recommended with an INR of 2.0 to 3.0. At the present time, anticoagulation with an INR between 3.0 and 4.5 cannot be recommended for patients with noncardiac TIA or stroke. Anticoagulation with an INR between 3.0 and 4.5 carries a high bleeding risk. Whether anticoagulation with lower INR is safe and effective is not yet known. Treatment of vascular risk factors should also be performed in secondary stroke prevention.

Treatment of lipid disorders after stroke

The efficacy of lipid disorder therapy for the primary and secondary prevention of coronary heart disease is established. There are, however, no completed studies specifically directed at reducing the risk of stroke with lipid therapy. Although observational cohort studies have failed to demonstrate an association between lipid disorders and stroke incidence, recently completed trials of subjects at risk for coronary heart disease have shown that statins and fibric acid derivatives reduce not only the risk of myocardial infarction and death, but also that of brain infarction and transient ischemic attacks. Lipid drugs are well tolerated and treatment complications are relatively low. It seems prudent to conclude that the stroke patient with an undesirable lipid profile who has a history of coronary heart disease should receive specific treatment for the lipid disorder. Recommendations are more problematic for stroke patients with lipid disorders but no history of coronary heart disease; most should receive therapy for primary prevention of heart disease. Lipid treatment trials focused on stroke risk reduction are urgently needed.

Long-term effectiveness and safety of pravastatin in 9014 patients with coronary heart disease and average cholesterol concentrations: the LIPID trial follow-up

BACKGROUND

The Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) study showed that pravastatin therapy over 6 years reduced mortality and cardiovascular events in patients with previous acute coronary syndromes and average cholesterol concentrations. We assessed the longer-term effects of initial treatment with pravastatin on further cardiovascular events and mortality over a total follow-up period of 8 years.

METHODS

In the main trial, 9014 patients with previous myocardial infarction or unstable angina and a baseline plasma cholesterol concentration of 4.0-7.0 mmol/L were randomly assigned pravastatin 40 mg daily or placebo and followed up for 6 years. Subsequently, all patients were offered open-label pravastatin for 2 more years. Major cardiovascular events and adverse events were compared according to initial treatment assignment.

FINDINGS

7680 (97% of those still alive) had 2 years of extended follow-up. 3766 (86%) of those assigned placebo and 3914 (88%) assigned pravastatin agreed to take open-label pravastatin. During this period, patients originally assigned pravastatin had almost identical cholesterol concentrations to those assigned placebo, but a lower risk of death from all causes (219 [5.6%] vs 255 [6.8%], p=0.029), coronary heart disease (CHD) death (108 [2.8%] vs 137 [3.6%], p=0.026), and CHD death or non-fatal myocardial infarction (176 [4.5%] vs 196 [5.2%], p=0.08). Over the total 8-year period, all-cause mortality was 888 (19.7%) in the group originally assigned placebo and 717 (15.9%) in the group originally assigned pravastatin, CHD mortality was 510 (11.3%) versus 395 (8.8%), myocardial infarction was 570 (12.7%) versus 435 (9.6%; each p < 0.0001), and stroke was 272 (6.0%) versus 224 (5.0%; p=0.015). Stronger evidence of separate treatment benefits than in the main trial was seen in important prespecified subgroups (women, patients aged > or = 70 years, and those with total cholesterol < 5.5 mmol/L). Pravastatin had no significant adverse effects.

INTERPRETATION

The evidence of sustained treatment benefits and safety of long-term pravastatin treatment reinforces the importance of long-term cholesterol-lowering treatment for almost all patients with previous CHD events.

How well tolerated are lipid-lowering drugs?

It has been clearly established that lipid-lowering treatments [such as 3-hydroxyl-3-methylglutamyl coenzyme A reductase inhibitors ('statins') or fibrates] can reduce cardiovascular events, and with one of the statins even total mortality, in high-risk populations. Intervention studies have not included the very old, but it is generally assumed that this patient group would benefit from these treatments to an extent similar to younger patients. Worries about the associations seen in observational studies between low cholesterol levels and cancer, cerebral haemorrhage or mood and behaviour change have been largely overcome by findings from the latest large drug intervention trials, which do not show any increase in these conditions with statin or fibrate treatments. The common adverse effects associated with these drugs are relatively mild and often transient in nature. Potentially more serious adverse effects, which are more clearly related to drug treatment and are probably dose-dependent, include elevations in hepatic transaminase levels and myopathy; however, these effects are uncommon and generally resolve rapidly when treatment is stopped. The risk of myopathy with fibrate treatment is increased in patients with renal impairment, and the risk of myopathy with statin treatment increases with co-administration of drugs that inhibit statin metabolism or transport. Other adverse effects are related to specific drugs, for example, clofibrate is associated with an increased risk of gallstones. Studies in elderly patients have not shown an increased risk of adverse effects with lipid-lowering drugs compared with younger patients, but in clinical practice there may be some increased risk, particularly with regards to drug interactions. Therefore, lipid-lowering drugs should be administered with extra caution to elderly patients.

Prevention of ischemic stroke

The primary risk factors for stroke are known, and attention to primary care of these disorders should reduce the incidence of stroke significantly. Control of hypertension, diabetes, and hyperlipidemia have all been shown to reduce the rate of stroke. Identification of potential cardioembolic sources of stroke, particularly atrial fibrillation, can prevent stroke with appropriate application of anticoagulation. Duplex Doppler B-mode sonography can establish the extent of carotid artery disease in patients with cervical bruit or risk factors for atherosclerosis, and indicate which conditions should be managed medically or surgically. Patients with a history suggestive of transient ischemic attacks can also be screened noninvasively with duplex sonography to determine if they have a critical carotid stenosis and require carotid endarterectomy. New advances in platelet antiaggregant therapy with ticlopidine, clopidegril, and the combination of aspirin with dipyridamole have also reduced the rate of stroke to a greater degree than standard treatment with aspirin. The incidence of this devastating illness could possibly be reduced by 50% with attentive primary care management. The cardiologist is often involved in the treatment of patients at risk for stroke, and is in an ideal position to provide this care.

Stroke prevention therapy beyond antithrombotics: unifying mechanisms in ischemic stroke pathogenesis and implications for therapy: an invited review

BACKGROUND

It is estimated that about half of cardiovascular disease risk is explained by conventional risk factors. The realization that atherosclerosis is an inflammatory disease has led to a search for new stroke and cardiovascular disease risk factors and treatments. As such, the vulnerable atherosclerotic plaque has become the main focus for new medical strategies for plaque stabilization and stroke prevention.

SUMMARY OF REVIEW

In this invited review, I discuss inflammation as a possible risk factor for stroke, unifying mechanisms in ischemic stroke pathogenesis, and new avenues for stroke prevention---statin agents, angiotensin-converting enzyme inhibitors, and vitamins. These new stroke prevention therapies may help to reduce inflammation, serve to stabilize the atherosclerotic plaque, or act by other protective mechanisms.

CONCLUSION

Beyond the traditional antithrombotic agents, statin agents, angiotensin-converting enzyme inhibitors, and vitamins may prove to be important additions to our armamentarium for stroke prevention.

Lowering lipids after a stroke or transient ischaemic attack

There is a lot of clinical uncertainty about how to aggressively pursue elevated cholesterol levels in patients following stroke or transient ischaemic attack. This article reviews the evidence linking cholesterol level with stroke and looks at whether treatment with lipid-lowering drugs can be justified.

Interventions in the management of serum lipids for preventing stroke recurrence

BACKGROUND

A close association between serum lipid levels and the incidence of coronary heart disease (CHD) has been well proven in middle aged and older persons, up to the age of 70-75 years. Individual studies have shown interventions to reduce total and low density lipoprotein (LDL) cholesterol levels, especially with 3-hydroxy-3-methylglutaryl coenzyme a (HMG-CoA) reductase inhibitors (statins), to be of benefit in reducing CHD and stroke events in those with a history of coronary heart disease. However, the relation of serum cholesterol and cholesterol sub-fractions with cerebrovascular disease is less clear. It is unclear whether lipid levels in the post-stroke period are a predictor of recurrence and whether treatment to alter levels can prevent recurrence of either stroke or cardiovascular events.

OBJECTIVES

To investigate the effect of altering serum lipids in the prevention of cardiovascular disease and stroke recurrence in subjects with a history of stroke.

SEARCH STRATEGY

The Cochrane Group Trials Register was searched up to 8 May 2001 along with MEDLINE (from 1966), EMBASE (from 1980) and the Cochrane Controlled Trials Register. All pharmaceutical firms known to produce a lipid lowering agent were also contacted and asked to provide information on publications or unpublished work relevant to this review.

SELECTION CRITERIA

This review included unconfounded randomised trials of subjects aged 18 years and over with a history of stroke or Transient Ischaemic Attack (TIA).

DATA COLLECTION AND ANALYSIS

The data were extracted independently by the three reviewers. MetaView 4.1 was used for all statistical analyses.

MAIN RESULTS

Five studies involving 1700 patients were included in the review. The active intervention in two of the studies was Clofibrate, Pravastatin in another two and Conjugated Oestrogen in the fifth. Fixed effects analysis showed no evidence of a difference in stroke recurrence between the treatment and placebo groups for those with a previous history of stroke or TIA (odds ratio 0.96, 95% confidence interval 0.71 to 1.30). In addition there was also no evidence, based on two studies, that intervention reduced the odds of all cause mortality (odds ratio 0.87, 95% confidence interval 0.55 to 1.39) nor, from one study, that there was any effect on subsequent vascular events (odds ratio 1.27, 95% confidence interval 0.84 to 1.89).

REVIEWER'S CONCLUSIONS

These trials do not provide evidence for a benefit, or harm, from interventions to alter serum lipid levels in patients with a history solely of cerebrovascular disease. Their use, therefore, cannot yet be recommended routinely in this patient group, but ischaemic stroke patients with a history of myocardial infarction should receive statin therapy along the lines of the previous recommendations for those patients with a history of myocardial ischaemia. There are currently three ongoing trials which will recruit approximately 30,000 patients, including those with a history of stroke, and the results of these trials may have a significant effect on these conclusions.

Blood lipids and first-ever ischemic stroke/transient ischemic attack in the Bezafibrate Infarction Prevention (BIP) Registry: high triglycerides constitute an independent risk factor

BACKGROUND

Despite unclear associations between blood lipids, including fractionated cholesterol and triglycerides, and stroke, recent evidence demonstrates that lipid-modifying agents decrease the risk of stroke in patients with coronary heart disease (CHD).

METHODS AND RESULTS

Patients with documented CHD who were screened for but not included in the Bezafibrate Infarction Prevention study and had no history of stroke or transient ischemic attack (TIA) (n=11 177) were followed up. At baseline, medical histories were obtained and blood lipids assessed at a central study laboratory. During a 6- to 8-year follow-up period, 941 patients were identified as having nonhemorrhagic cerebrovascular disease, of whom 487 had verified ischemic stroke (per clinical findings and brain CT) or TIA. Patients experiencing an ischemic stroke/TIA had higher mean levels of triglycerides, lower levels of HDL cholesterol, and lower percentages of cholesterol contained in the HDL cholesterol moiety (%HDL; P<0.01 for all). In a logistic regression model, the adjusted ORs for developing an ischemic stroke/TIA were 1.27 (95% CI 1.01 to 1.60) associated with triglycerides >200 mg/dL and 0.87 (95% CI 0.78 to 0.97) associated with a 5% decrease in %HDL. The increased risk associated with high triglycerides was found across subgroups of age, sex, patient characteristics, and cholesterol fractions.

CONCLUSIONS

High triglycerides constitute an independent risk factor for ischemic stroke/TIA across subgroups of age, sex, patient characteristics, and cholesterol fractions, whereas high %HDL was an independent protective factor among patients with CHD. These findings support the role of blood lipids, including triglycerides, as important modifiable stroke risk factors.

Pravastatin improves cerebral vasomotor reactivity in patients with subcortical small-vessel disease

BACKGROUND AND PURPOSE

Recent investigations have suggested an important role of statins in the prevention of stroke and dementia independent of their lipid-lowering properties. Using transcranial Doppler sonography (TCD), we examined acetazolamide reactivity as a marker of cerebral vasoreactivity in patients with subcortical small-vessel disease before and after pravastatin treatment.

METHODS

In 16 patients (mean age 68+/-10 years) with subcortical small-vessel disease, cerebral vasomotor reactivity was tested using TCD insonating the middle cerebral artery. Cerebral blood flow velocity (CBFV) increase after bolus injection of 1 g acetazolamide was determined before and after 2-month treatment with pravastatin sodium 20 mg daily.

RESULTS

Relative CBFV increase was significantly greater after pravastatin treatment (41.9+/-23.7% versus 55.7+/-18.3%, P=0.004). Comparison of CBFV at rest before and after treatment with pravastatin did not show significant differences. There was a strong negative correlation between the pravastatin-induced enhancement of vasomotor reactivity and the pretreatment CBFV increase (beta=-0.64, P=0.019). No associations were found between the effect of pravastatin on vasomotor reactivity and pretreatment levels or changes of LDL cholesterol.

CONCLUSIONS

This pilot study provides the first evidence for a significant improvement of cerebral vasomotor reactivity by statin therapy in patients with cerebral small-vessel disease. The results may help to elucidate the preventive effect of statins and provide insights into the pathophysiology of cerebral small-vessel disease.

Nutraceuticals: vitamins and other nutrients in coronary heart disease

Nutraceuticals and specifically vitamins, oils and herbs are increasingly being taken by patients. Some supplements may improve cardiovascular outcome, most are unproved, and some could potentially cause harm. Marine lipid supplementation needs to be considered in all patients who have manifest coronary heart disease. For most supplements more data are needed before confident recommendations can be made.

Cholesterol and other lipids predict coronary heart disease and ischaemic stroke in the elderly, but only in those below 70 years

The prediction of coronary heart disease (CHD) and stroke by total and low density lipoprotein (LDL) cholesterol in older persons remains problematical. This study tests the hypothesis that cholesterol and other risk factors may be differentially predictive of CHD and ischaemic stroke in older persons when they are segregated into different age groups. CHD and ischaemic stroke outcomes were recorded during 129 months follow-up in a cohort of 2805 men and women of 60 years and older. There were 899 CHD events (32/100) and 326 stroke events (12/100). Using Cox proportional hazards, outcomes were modelled for the total cohort and for age groups 60-69, 70-79, and 80+ years. Total cholesterol, LDL cholesterol, serum apo-B, total cholesterol/high density lipoprotein (HDL) cholesterol and apo-B/apo-A1 were significant predictors of CHD in the total cohort, but significant only in the sub-group of 60-69 years. The respective hazard ratios (CI 95%) were 1.21 (1.09-1.35), 1.21 (1.09-1.35), 1.25 (1.13-1.39), 1.25 (1.14-1.37) and 1.21 (1.10-1.38). Similar findings were applicable with respect to ischaemic stroke in the age group of 60-69 years. Total cholesterol predicted CHD in men above a threshold value of 7.06 mmol/l and in women above 7.8 mmol/l, but with stroke the prediction was incremental. Other risk factors such as HDL cholesterol, triglycerides, lipoprotein(a), diabetes, hypertension and smoking predicted CHD, although only HDL and hypertension similarly predicted ischaemic stroke. The findings support a case for cholesterol testing in older subjects up to 70 years, in whom there is ancillary evidence of CHD and stroke prevention through treatment designed to reduce LDL cholesterol.