European Stroke Prevention Study. ESPS Group

The pharmacology of antiplatelet agents for primary, secondary, and tertiary prevention of ischemic stroke

INTRODUCTION

Ischemic etiology accounts for two thirds of all strokes in which platelet activation and aggregation play a major role. A variety of antiplatelet therapies have been tested for primary, secondary, and tertiary prevention, with certain patient subtypes benefiting more than others from a specific regimen.

AREAS COVERED

This review aims at synthetizing current evidence on pharmacology of antiplatelet agents approved for primary, secondary, and tertiary stroke prevention and their application among possible patient subtypes that may benefit more from their administration.

EXPERT OPINION

Management of ischemic stroke has largely evolved over the past decades. A better understanding of stroke pathophysiology has allowed to identify patients who can benefit most from antiplatelet therapies, with varying degrees of benefit depending on whether these agents are being used for primary, secondary, or tertiary prevention. Importantly, the antiplatelet treatment regimens currently available have expanded and no longer limited to aspirin but include other drugs such as P2Y12 and phosphodiesterase inhibitors, also used in combination, as well as precision medicine approaches using genetic testing aiming at optimizing the safety and efficacy in this population.

Dual Antiplatelet Therapy for the Acute Management and Long-term Secondary Prevention of Ischemic Stroke and Transient Ischemic Attack, An Updated Review

To improve the efficacy over antiplatelet monotherapy, dual antiplatelet therapy (DAPT) has been increasingly adopted in the management of non-cardioembolic stroke. For minor ischemic stroke and high-risk transient ischemic attack, the aspirin-clopidogrel combination is now recommended for acute short-term treatment, whereas aspirin-ticagrelor combination may be considered in selected patients, especially those with resistance to clopidogrel. For long-term stroke prevention, aspirin-dipyridamole combination has been used as an alternative to antiplatelet monotherapy, and aspirin or clopidogrel combined with cilostazole may be prescribed for added protection in high-risk patients. In this paper, we review the development of DAPT from a historical perspective and describe the findings from major clinical trials published up until the end of 2023. Using the 2021 American Heart Association guideline for secondary stroke prevention as a basis for our recommendations, we further discuss areas of controversy and more recent developments to provide an updated review for clinicians to consider in their daily practice.

Effect of an herbal medicine, Chunghyul-dan, on prevention of recurrence in patients with ischemic stroke: A retrospective cohort study

Research indicates that Chunghyul-dan (CHD), a herbal medicine, has an inhibitory effect on stroke recurrence in small vessel disease. Recent studies have suggested that CHD might also act on large arteries. This study aimed to verify the preventive effect of CHD on strokes of all the Trial of Org 10172 in Acute Stroke Treatment (TOAST) causative classifications. We retrospectively analyzed 2 years of medical records of patients with ischemic stroke treated with CHD, 600 mg once daily, in combination with antiplatelet or anticoagulant agents. The prevalence of stroke recurrence in 2 years was analyzed. Stroke recurrence was defined as new neurological symptoms with corresponding brain imaging results. Nine of the 202 patients (4.46%) had recurrent ischemic stroke. Four occurred within 180 days, 3 between 180 and 365 days, and 2 between 365 and 730 days. All had only 1 recurrence. The recurrence rates were 1.12%, 5%, and 5.48% for small vessel occlusion, cardioembolism, and large vessel atherosclerosis, respectively. There were no adverse effects. These results suggest that CHD could inhibit ischemic stroke recurrence of all TOAST causative categories. A randomized controlled trial is needed to confirm this hypothesis.

Antithrombotic Therapy for Primary and Secondary Prevention of Ischemic Stroke: JACC State-of-the-Art Review

Stroke is a devastating condition with significant morbidity and mortality worldwide. Antithrombotic therapy plays a crucial role in both primary and secondary prevention of stroke events. Single or dual antiplatelet therapy is generally preferred in cases of large-artery atherosclerosis and small-vessel disease, whereas anticoagulation is recommended in conditions of blood stasis or hypercoagulable states that mostly result in red thrombi. However, the benefit of antithrombotic therapies must be weighed against the increased risk of bleeding, which can pose significant challenges in the pharmacological management of this condition. This review provides a comprehensive summary of the currently available evidence on antithrombotic therapy for ischemic stroke and outlines an updated therapeutic algorithm to support physicians in tailoring the strategy to the individual patient and the underlying mechanism of stroke.

European Stroke Organisation (ESO) guideline on pharmacological interventions for long-term secondary prevention after ischaemic stroke or transient ischaemic attack

Recurrent stroke affects 9% to 15% of people within 1 year. This European Stroke Organisation (ESO) guideline provides evidence-based recommendations on pharmacological management of blood pressure (BP), diabetes mellitus, lipid levels and antiplatelet therapy for the prevention of recurrent stroke and other important outcomes in people with ischaemic stroke or transient ischaemic attack (TIA). It does not cover interventions for specific causes of stroke, including anticoagulation for cardioembolic stroke, which are addressed in other guidelines. This guideline was developed through ESO standard operating procedures and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified clinical questions, selected outcomes, performed systematic reviews, with meta-analyses where appropriate, and made evidence-based recommendations, with expert consensus statements where evidence was insufficient to support a recommendation. To reduce the long-term risk of recurrent stroke or other important outcomes after ischaemic stroke or TIA, we recommend: BP lowering treatment to a target of <130/80 mmHg, except in subgroups at increased risk of harm; HMGCoA-reductase inhibitors (statins) and targeting a low density lipoprotein level of <1.8 mmol/l (70 mg/dl); avoidance of dual antiplatelet therapy with aspirin and clopidogrel after the first 90 days; to not give direct oral anticoagulant drugs (DOACs) for embolic stroke of undetermined source and to consider pioglitazone in people with diabetes or insulin resistance, after careful consideration of potential risks. In addition to the evidence-based recommendations, all or the majority of working group members supported: out-of-office BP monitoring; use of combination treatment for BP control; consideration of ezetimibe or PCSK9 inhibitors when lipid targets are not achieved; consideration of use of low-dose DOACs in addition to an antiplatelet in selected groups of people with coronary or peripheral artery disease and aiming for an HbA1c level of <53 mmol/mol (7%) in people with diabetes mellitus. These guidelines aim to standardise long-term pharmacological treatment to reduce the burden of recurrent stroke in Europe.

Antithrombotic therapies in aortic and peripheral arterial diseases in 2021: a consensus document from the ESC working group on aorta and peripheral vascular diseases, the ESC working group on thrombosis, and the ESC working group on cardiovascular pharmacotherapy

The aim of this collaborative document is to provide an update for clinicians on best antithrombotic strategies in patients with aortic and/or peripheral arterial diseases. Antithrombotic therapy is a pillar of optimal medical treatment for these patients at very high cardiovascular risk. While the number of trials on antithrombotic therapies in patients with aortic or peripheral arterial diseases is substantially smaller than for those with coronary artery disease, recent evidence deserves to be incorporated into clinical practice. In the absence of specific indications for chronic oral anticoagulation due to concomitant cardiovascular disease, a single antiplatelet agent is the basis for long-term antithrombotic treatment in patients with aortic or peripheral arterial diseases. Its association with another antiplatelet agent or low-dose anticoagulants will be discussed, based on patient's ischaemic and bleeding risk as well therapeutic paths (e.g. endovascular therapy). This consensus document aims to provide a guidance for antithrombotic therapy according to arterial disease localizations and clinical presentation. However, it cannot substitute multidisciplinary team discussions, which are particularly important in patients with uncertain ischaemic/bleeding balance. Importantly, since this balance evolves over time in an individual patient, a regular reassessment of the antithrombotic therapy is of paramount importance.

Antithrombotic Therapy for Secondary Prevention in Patients with Non-Cardioembolic Stroke or Transient Ischemic Attack: A Systematic Review

Stroke embodies one of the leading causes of death and disability worldwide. We aimed to provide a comprehensive insight into the effectiveness and safety of antiplatelet agents and anticoagulants in the secondary prevention of ischemic stroke or transient ischemic attack. A systematic search for randomized controlled trials, comparing antiplatelet or anticoagulant therapy versus aspirin or placebo among patients with ischemic stroke or transient ischemic attack, was performed in order to summarize data regarding the different regimens. Keyword-based searches in the MEDLINE, EMBASE, and Cochrane Library databases were conducted until the 1st of January 2021. Our search explored 46 randomized controlled trials involving ten antiplatelet agents, six combinations with aspirin, and four anticoagulant therapies. The review of the literature reflects that antiplatelet therapy improves outcome in patients with ischemic stroke or transient ischemic attack. Monotherapy proved to be an effective and safe choice, especially in patients with a high risk of bleeding. Intensified antiplatelet regimens further improve stroke recurrence; however, bleeding rate increases while mortality remains unaffected. Supplementing the clinical judgment of stroke treatment, assessment of bleeding risk is warranted to identify patients with the highest benefit of treatment intensification.

Management of carotid stenosis for primary and secondary prevention of stroke: state-of-the-art 2020: a critical review

Carotid atherosclerotic plaque is encountered frequently in patients at high cardiovascular risk, especially in the elderly. When plaque reaches 50% of carotid lumen, it induces haemodynamically significant carotid stenosis, for which management is currently at a turning point. Improved control of blood pressure, smoking ban campaigns, and the widespread use of statins have reduced the risk of cerebral infarction to <1% per year. However, about 15% of strokes are still secondary to a carotid stenosis, which can potentially be detected by effective imaging techniques. For symptomatic carotid stenosis, current ESC guidelines put a threshold of 70% for formal indication for revascularization. A revascularization should be discussed for symptomatic stenosis over 50% and for asymptomatic carotid stenosis over 60%. This evaluation should be performed by ultrasound as a first-line examination. As a complement, computed tomography angiography (CTA) and/or magnetic resonance angiography are recommended for evaluating the extent and severity of extracranial carotid stenosis. In perspective, new high-risk markers are currently being developed using markers of plaque neovascularization, plaque inflammation, or plaque tissue stiffness. Medical management of patient with carotid stenosis is always warranted and applied to any patient with atheromatous lesions. Best medical therapy is based on cardiovascular risk factors correction, including lifestyle intervention and a pharmacological treatment. It is based on the tri-therapy strategy with antiplatelet, statins, and ACE inhibitors. The indications for carotid endarterectomy (CEA) and carotid artery stenting (CAS) are similar: for symptomatic patients (recent stroke or transient ischaemic attack ) if stenosis >50%; for asymptomatic patients: tight stenosis (>60%) and a perceived high long-term risk of stroke (determined mainly by imaging criteria). Choice of procedure may be influenced by anatomy (high stenosis, difficult CAS or CEA access, incomplete circle of Willis), prior illness or treatment (radiotherapy, other neck surgery), or patient risk (unable to lie flat, poor AHA assessment). In conclusion, neither systematic nor abandoned, the place of carotid revascularization must necessarily be limited to the plaques at highest risk, leaving a large place for optimized medical treatment as first line management. An evaluation of the value of performing endarterectomy on plaques considered to be at high risk is currently underway in the ACTRIS and CREST 2 studies. These studies, along with the next result of ACST-2 trial, will provide us a more precise strategy in case of carotid stenosis.

Early Secondary Prevention in Transient Ischemic Attack (TIA) and Minor Stroke

PURPOSE OF REVIEW

The purpose of this study was to review recent literature on the early secondary prevention in transient ischemic attack (TIA) and minor stroke.

RECENT FINDINGS

The result of Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events and the secondary analysis of Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) have shown that treatment with clopidogrel and aspirin for 21 days reduced the risk of recurrent stroke with no significant increase in bleeding risk. Triple antiplatelet therapy with aspirin, clopidogrel, and dipyridamole resulted in a significant increase in major (including fatal) bleeding with no significant reduction in the recurrent stroke or TIA. The early treatment of patients with TIA or minor stroke with clopidogrel and aspirin for 21 days was effective in reducing the risk of recurrent stroke with no significant increase in bleeding risk. Most stroke guidelines have been updated to reflect this recommendation.

Inhibitory Effect of Chunghyul-dan on Stroke Recurrence in Small Vessel Disease Patients: A 5-Year Observational Study

We investigated the stroke recurrence rate and the rate of adverse effects induced by an herbal medicine, Chunghyul-dan, administered to patients over a 5-year period. We prescribed 600 mg Chunghyul-dan a day to patients with small vessel diseases and investigated stroke recurrence, adverse effects, and drug compliance for 5 years. The primary outcome was the prevalence of stroke recurrence (in 3, 4, and 5 years). The secondary outcome was the frequency of adverse effects induced by Chunghyul-dan. We recruited 400 patients. Among them, 270, 233, and 195 patients completed 3, 4, and 5 years of follow-up, respectively. Among patients who completed 3, 4, and 5 years of follow-up, cumulative recurrent stroke occurred in 7 (2.6%), 11 (4.7%), and 12 (6.2%) patients. There were no adverse effects. We suggest that Chunghyul-dan might be useful for the inhibition of stroke recurrence by reducing microangiography progression. Further study is needed to confirm our hypothesis.

Comparative efficacy and safety of antiplatelet agents in cerebral ischemic disease: A network meta-analysis

We performed a network meta-analysis (NMA) to enhance the corresponding evidence of the relative efficacy and safety of different antiplatelet agents in cerebral ischemic disease. PubMed and EMBASE were searched systematically for relevant studies. Outcomes were compared using odds ratios and 95% credible intervals. Each agent was ranked according to the value of surface under the cumulative ranking curve (SUCRA). Publication bias was evaluated by funnel plots, while consistency between direct and indirect comparison was analyzed by node-splitting and heat plots. Besides, the clustering technique was used to categorize similar agents. A number of 44 eligible studies with 148 578 patients were included in this NMA. In terms of efficacy (including mortality, recurrent stroke, and vascular event), all six interventions were better than placebo. clopidogrel (Clop) and aspirin (ASA)+Clop were the best two interventions from SUCRA. However, the performance of ASA+Clop declined significantly when considering safety (including myocardial infarction, all-cause withdrawal, and intracranial hemorrhage), especially worse in intracranial hemorrhage. In conclusion, Clop was potentially the most preferable treatment for preventing cerebral ischemic in terms of efficacy and safety. However, the addition of ASA was associated with a potential increase in intracranial hemorrhage, therefore, combination therapy of ASA and Clop should be introduced with caution although it may be more effective than the monotherapy of ASA.

The Effects of Chunghyul-Dan (A Korean Medicine Herbal Complex) on Cardiovascular and Cerebrovascular Diseases: A Narrative Review

Chunghyul-dan (CHD) is a herbal complex containing 80% ethanol extract and is composed of Scutellariae Radix, Coptidis Rhizoma, Phellodendri Cortex, Gardeniae Fructus, and Rhei Rhizoma. We have published several experimental and clinical research articles on CHD. It has shown antilipidemic, antihypertensive, antiatherosclerotic, and inhibitory effects on ischemic stroke recurrence with clinical safety in the previous studies. The antilipidemic effect of CHD results from 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and pancreatic lipase-inhibitory activity. The antihypertensive effect likely results from the inhibitory effect on endogenous catecholamine(s) release and harmonization of all components showing the antihypertensive effects. Furthermore, anti-inflammatory and antioxidant effects on endothelial cells are implicated to dictate the antiatherosclerotic effects of CHD. It also showed neuroprotective effects on cerebrovascular and parkinsonian models. These effects of CHD could be helpful for the prevention of the recurrence of ischemic stroke. Therefore, we suggest that CHD could be a promising medication for treating and preventing cerebrovascular and cardiovascular diseases. However, to validate and better understand these findings, well-designed clinical studies are required.

Antiplatelet regimens in the long-term secondary prevention of transient ischaemic attack and ischaemic stroke: an updated network meta-analysis

OBJECTIVE

To examine the comparative efficacy and safety of different antiplatelet regimens in patients with prior non-cardioembolic ischaemic stroke or transient ischaemic attack.

DESIGN

Systematic review and network meta-analysis.

DATA SOURCES

As on 31 March 2015, all randomised controlled trials that investigated the effects of antiplatelet agents in the long-term (≥ 3 months) secondary prevention of non-cardioembolic transient ischaemic attack or ischaemic stroke were searched and identified.

OUTCOME MEASURES

The primary outcome measure of efficacy was serious vascular events (non-fatal stroke, non-fatal myocardial infarction and vascular death). The outcome measure of safety was any bleeding.

RESULTS

A total of 36 randomised controlled trials (82,144 patients) were included. Network meta-analysis showed that cilostazol was significantly more effective than clopidogrel (OR 0.77, 95% credible interval 0.60-0.98) and low-dose (75-162 mg daily) aspirin (0.69, 0.55-0.86) in the prevention of serious vascular events. Aspirin (50 mg daily) plus dipyridamole (400 mg daily) and clopidogrel reduced the risk of serious vascular events compared with low-dose aspirin; however, the difference was not statistically significant. Furthermore, low-dose aspirin was as effective as higher daily doses. Cilostazol was associated with a significantly lower bleeding risk than most of the other regimens. Moreover, aspirin plus clopidogrel was associated with significantly more haemorrhagic events than other regimens. Direct comparisons showed similar results as the network meta-analysis.

CONCLUSIONS

Cilostazol was significantly more effective than aspirin and clopidogrel alone in the long-term prevention of serious vascular events in patients with prior non-cardioembolic ischaemic stroke or transient ischaemic attack. Cilostazol was associated with a significantly lower bleeding risk than low-dose aspirin (75-162 mg daily) and aspirin (50 mg daily) plus dipyridamole (400 mg daily). Low-dose aspirin was as effective as higher daily doses. However, further large, randomised, controlled, head-to-head trials are needed, especially in non-Asian ethnic groups.

Comparative Efficacy and Safety of Nine Anti-Platelet Therapies for Patients with Ischemic Stroke or Transient Ischemic Attack: a Mixed Treatment Comparisons

Anti-platelet treatments, an effective anti-thrombotic therapy, are widely used in non-cardioembolic ischemic stroke or transient ischemic attack (TIA), including aspirin, cilostazol, clopidogrel, and other mono or dual therapies, while the optimal choice remains uncertain. All the literatures of 38 eligible randomized control trials were searched in PubMed, Embase, and China National Knowledge Internet (CNKI) without language limitation. And, nine anti-platelet therapies were assessed, including aspirin, clopidogrel, cilostazol, ticlopidine, triflusal, terutroban, sarpogrelate, dipyridamole plus aspirin, and clopidogrel plus aspirin. Additionally, we extract data of composite vascular events, major bleeding, ischemic stroke, intracranial hemorrhage, and all-cause death, as indicators of efficacy and safety. And among them, composite vascular events were the primary outcome. The binary outcomes were expressed as odds ratios (ORs) with corresponding 95 % confidence intervals (CIs). Both traditional meta-analysis and network meta-analysis were performed. Besides, for each outcome, the rank order was applied to reflect the superiority of every therapy compared with others, using the surface under the cumulative ranking curve (SUCRA). A cluster analysis was also conducted. Through the network meta-analysis, the synthesized data shows that cilostazol performed best on composite vascular events compared with placebo (OR = 0.62, 95 % CI 0.46-0.83) and aspirin (OR = 0.71, 95 % CI 0.53-0.95). In terms of ischemic stroke, clopidogrel plus aspirin seems the optimal, and it has significant difference between placebo (OR = 0.53, 95 % CI 0.35-0.74) and aspirin (OR = 0.75, 95 % CI 0.61-0.95). Meanwhile, cilostazol is also the first rank in major bleeding, especially when it is in contrast to aspirin (OR = 0.13, 95 % CI 0.02-0.70) and clopidogrel plus aspirin (OR = 0.09, 95 % CI 0.01-0.50). There is no significant difference among these nine treatments and placebo, as to all-cause death and intracranial hemorrhage. According to the cluster analysis, cilostazol can be the best choice with comprehensive assessment of composite vascular events, ischemic stroke and major bleeding. Based on this network meta-analysis, cilostazol was recommended as the optimal choice with good performance in both efficacy and safety for patient with ischemic stroke or TIA among nine anti-platelet therapies.

Risk factors associated with ischemic heart disease occurence in acute ischemic stroke patients

AIMS

At specific time periods following ischemic stroke (IS), acute coronary syndrome as ischemic heart disease (IHD) represents a higher risk of death than IS. Not all IS patients can undergo specific examination for IHD detection. The aim of this study was to assess exclusive risk factors (RFs) associated with IHD occurrence in IS patients. Knowledge of these RFs should help in stratifying IS patients for IHD detection.

MATERIALS AND METHODS

This was a hospital-based, retrospective, single centre study. The sample consisted of 192 consecutive IS patients, divided into two subgroups - Subgroup 1 (54 patients without IHD; 55.6% males; 63.1 ± 11.8 years) and Subgroup 2 (138 patients with IHD; 39.1% males; 76.3 ± 9.6 years). The following factors were identified: age; sex; presence of arterial hypertension, atrial fibrillation, diabetes mellitus; plasma levels of total cholesterol, triglycerides, low-density cholesterol, high-density cholesterol; body mass index; presence of carotid plaques. Logistic regression analysis was used for statistical evaluation.

RESULTS

Of all identified risk factors only age (OR=1.109; 95% CI: 1.069 - 1.150, P=0.001) and the presence of arterial hypertension (OR=6.298; 95% CI: 2.215 - 17.905, P=0.003) were exclusively and significantly associated with the presence of IHD in IS patients.

CONCLUSIONS

Age and arterial hypertension may be exclusive risk factors associated with IHD in IS patients.

Headache and cardiovascular disease: old symptoms, new proposals

Evidence of a link between headache symptoms and cardiovascular disease has rapidly grown in recent years and it is of utmost importance for the cardiologist and neurologist to be aware of this intimate connection. A brief overview of different cardiovascular diseases (namely hypertension, stroke, coronary heart disease, patent foramen ovale, atrial septal defects, atrial septal aneurisms, mitral valve prolapse, and aortic and carotid disease) that may be related to headache is presented in this article. Proposed pathophysiological mechanisms for this association and landmark studies are reviewed and discussed.

Platelet-endothelial interactions in atherothrombotic disease: therapeutic implications

The role of the platelet and the endothelium in the pathogenesis of atherosclerosis and subsequent ischemic events has been the subject of extensive investigation. Arterial sites where endothelial function is severely impaired are often the sites of atheroma development. Lesion evolution impairs endothelial function, leading to a self-perpetuating cycle of growth. During early lesion development, overt thrombotic events are rare. However, rupture of an advanced, necrotic plaque or intimal ulceration triggers arterial thrombosis, at which point the importance of platelet function may be seen clearly. The Antiplatelet Trialists' Collaboration meta-analysis demonstrated the benefit of antiplatelet therapy to patients with atherosclerotic disease. Aspirin is the most widely studied agent and is considered the standard of antiplatelet therapy. Newer agents that intervene at different stages of the platelet activation pathway have been developed. Clopidogrel, a new adenosine diphosphate receptor antagonist, is more effective than aspirin in reducing vascular events in patients with prior myocardial infarction, stroke, or established peripheral arterial disease. The glycoprotein IIb-IIIa antagonists such as abciximab have proven effective in the setting of active arterial thrombosis and percutaneous revascularization, but their value in secondary prevention remains unknown. All patients with atherosclerosis should be treated with an antiplatelet drug. Current evidence suggests that either aspirin or clopidogrel are appropriate first-line agents. There is urgent need for an analysis of the risk/benefit ratio in various populations and clinical settings to determine the most appropriate type and intensity of therapy for a given patient.

Stroke treatment: beyond the three-hour window and in the pregnant patient

For acute stroke patients who arrive at the hospital within 3 h of symptom onset, the focus of care involves screening for eligibility to receive intravenous tissue plasminogen activator. The publication of the National Institute of Neurological Disorders and Stroke recombinant tissue-type plasminogen activator (tPA, or alteplase) study in 1995 (Marler, J.R. 1995, New England Journal of Medicine333: 1581-1587) spurred protocol changes, which continue to evolve, throughout the health care system in an effort to streamline the patient through the Emergency Medical System. The need to expedite patient evaluation involving emergency department, laboratory, radiology, and clinical neurology testing is clear and has been a focus of many stroke centers. For some patients, intravenous thrombolysis within 3 h has a dramatic effect on outcome. However, that is not the only course of action for acute stroke patients. This article will review some of the effective treatments for stroke patients beyond the first 3 h of their care.

Review: Recurrent stroke: where do we stand with the secondary prevention of noncardioembolic ischaemic strokes?

Strokes recur in 6—20% of the patients, most commonly within the first year; after a TIA or minor stroke; most recurrences will occur within the first 90 days. Our ability to identify patients at high risk is poor and most recurrent strokes cannot be explained by traditional risk factors. In 30—45% of the cases the second stroke will be of a different subtype. Moreover, patients are faced with other risks, like cardiac events and cognitive decline. With the population aging, the need for timely and effective secondary prevention strategies is more pressing than ever. This paper summarizes recent advances in pharmacological secondary prevention after a non-cardioembolic ischaemic stroke, and highlights critical questions still in need of answers.

A randomised controlled trial of triple antiplatelet therapy (aspirin, clopidogrel and dipyridamole) in the secondary prevention of stroke: safety, tolerability and feasibility

BACKGROUND

Aspirin, dipyridamole and clopidogrel are effective in secondary vascular prevention. Combination therapy with three antiplatelet agents might maximise the benefit of antiplatelet treatment in the secondary prevention of ischaemic stroke.

METHODOLOGY/PRINCIPAL FINDINGS

A randomised, parallel group, observer-blinded phase II trial compared the combination of aspirin, clopidogrel and dipyridamole with aspirin alone. Adult patients with ischaemic stroke or transient ischaemic attack (TIA) within 5 years were included. The primary outcome was tolerability to treatment assessed as the number of patients completing randomised treatment. Recruitment was halted prematurely after publication of the ESPRIT trial (which confirmed that combined aspirin and dipyridamole is more effective than aspirin alone). 17 patients were enrolled: male 12 (71%), mean age 62 (SD 13) years, lacunar stroke syndrome 12 (71%), median stroke/TIA onset to randomisation 8 months. Treatment was discontinued in 4 of 9 (44%) patients receiving triple therapy vs. none of 8 taking aspirin (p = 0.08). One recurrent stroke occurred in a patient in the triple group who was noncompliant of all antiplatelet medications. The number of patients with adverse events and bleeding complications, and their severity, were significantly greater in the triple therapy group (p<0.01).

CONCLUSIONS/SIGNIFICANCE

Long term triple antiplatelet therapy was asociated with a significant increase in adverse events and bleeding rates, and their severity, and a trend to increased discontinuations. However, the patients had a low risk of recurrence and future trials should focus on short term therapy in high risk patients characterised by a very recent event or failure of dual antiplatelet therapy.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN83673558.

A preliminary study on the inhibitory effect of Chunghyul-dan on stroke recurrence in patients with small vessel disease

OBJECTIVE

Chunghyul-dan is a combinatorial herbal medicine, and previous works reported that it had therapeutic effects for microangiopathy, which is a major part in the progression of small vessel disease, as having anti-hypertensive, anti-hyperlipidemic, anti-apoptotic, anti-oxidative and anti-inflammatory activities. Therefore, we examined the inhibitory effect of Chunghyul-dan on stroke recurrence in patients with small vessel disease.

METHODS

We prescribed Chunghyul-dan 600 mg a day to the patients with small vessel disease, and monitored stroke recurrence, drug compliances and adverse effect for 2 years. And then we performed follow-up brain MRI to find new vascular lesion after 2 years of Chunghyul-dan medication. As for the control, we recruited the subjects who had been managed with antiplatelet agents from a western medical hospital, and compared the rate of stroke recurrence.

RESULTS

There were 148 subjects who had been treated with Chunghyul-dan for 2 years, and new vascular events were found in three subjects. On the other hand, 208 subjects were managed with anti-platelet agents for 2 years in a Western medical hospital, and 17 of them had stroke recurrence. Therefore, 2 years of Chunghyul-dan medication reduced the odds ratio of stroke recurrence by 77% compared to the anti-platelet agents managed control. The inhibition rate increased to 79%, when adjusted for other relevant risk factors for stroke occurrence. During the study, no adverse effect was detected.

CONCLUSION

We suggest that Chunghyul-dan could be useful for inhibition of stroke recurrence by preventing the progression of microangiopathy. Further study with a randomized controlled trial is needed to confirm this suggestion.

Antiplatelet agents for stroke prevention following transient ischemic attack

Regardless of extent or duration of acute effects, transient ischemic attack (TIA) is a marker for cerebrovascular ischemia and carries risk for secondary stroke comparable to that associated with ischemic stroke. Pharmacologic and nonpharmacologic interventions aimed at reducing risk of secondary stroke should be implemented as soon as possible after characterization of the initial event. Medical strategies for secondary prevention include modifying general cardiovascular risk factors but are centered on the specific reduction of stroke risk by antiplatelet agents. Aspirin and clopidogrel have each demonstrated efficacy in reducing secondary event risk; however, clopidogrel has not been shown specifically to prevent secondary events in patients who have had a TIA or stroke. Combination therapy using aspirin plus dipyridamole is the only combination approach to demonstrate additive benefit that is significantly greater than that conferred by aspirin. In contrast, the combination of clopidogrel plus aspirin has not demonstrated significant benefit over monotherapy with either agent and has been associated with increased risk of bleeding episodes.

Triple antiplatelet therapy for secondary prevention of recurrent ischemic stroke

Antiplatelet agents are effective for secondary prevention after ischemic stroke, although they do not always prevent recurrent events. Laboratory studies confirm that therapy with 3 antiplatelet agents is superior to dual therapy or monotherapy at inhibiting platelet and leucocyte function. We report here a 69-year-old man who had recurrent strokes despite single or dual antiplatelet agents, but who responded to a combination of aspirin, dipyridamole, and clopidogrel. Likewise, triple antiplatelet therapy was effective in a series of 8 additional patients during a period of 28 months of follow up. Because combining 3 agents runs the risk of major bleeding, clinical trials are essential to address issues of safety and efficacy in patients with stroke.

Dipyridamole for preventing stroke and other vascular events in patients with vascular disease

BACKGROUND

Patients with limited cerebral ischaemia of arterial origin are at risk of serious vascular events (4% to 11% annually). Aspirin reduces that risk by 13%. In one trial, adding dipyridamole to aspirin was associated with a 22% risk reduction compared with aspirin alone. However, a systematic review of all trials of antiplatelet agents by the Antithrombotic Trialists' Collaboration showed that, in high-risk patients, there was virtually no difference between the aspirin-dipyridamole combination and aspirin alone.

OBJECTIVES

To assess the efficacy and safety of dipyridamole versus control in the secondary prevention of vascular events in patients with vascular disease.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (searched June 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2006), MEDLINE (1966 to May 2006) and EMBASE (1980 to May 2006). We contacted authors and pharmaceutical companies in the search for further data on published and unpublished studies.

SELECTION CRITERIA

We selected randomised long-term secondary prevention trials with concealed treatment allocation, treatment for more than one month, starting within six months after presentation of an arterial vascular disease. Treatment consisted of dipyridamole with or without other antiplatelet drugs compared with no drug or an antiplatelet drug other than dipyridamole.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality and extracted data. Data were analysed according to the intention-to-treat principle.

MAIN RESULTS

Twenty-nine trials were included, with 23019 participants, among whom 1503 vascular deaths and 3438 fatal and non-fatal vascular events occurred during follow up. Compared with control, dipyridamole had no clear effect on vascular death (relative risk (RR) 0.99, 95% confidence interval (CI) 0.87 to 1.12). This result was not influenced by the dose of dipyridamole or type of presenting vascular disease. Compared with control, dipyridamole appeared to reduce the risk of vascular events (RR 0.88, 95% CI 0.81 to 0.95). This effect was only statistically significant in patients presenting with cerebral ischaemia.

AUTHORS' CONCLUSIONS

For patients who presented with arterial vascular disease, there was no evidence that dipyridamole, in the presence or absence of another antiplatelet drug reduced the risk of vascular death, though it reduces the risk of further vascular events. This benefit was found only in patients presenting after cerebral ischaemia. There was no evidence that dipyridamole alone was more efficacious than aspirin.

Secondary prevention of stroke and transient ischemic attack: is more platelet inhibition the answer?

BACKGROUND

Recurrent cerebrovascular events constitute an estimated 200,000 of the 700,000 strokes reported annually in the United States, which makes secondary stroke prevention an important goal in the management of disease among patients who have experienced stroke or transient ischemic attack.

METHODS AND RESULTS

Various pharmacological approaches have been advocated, but the relative efficacy and safety of these regimens has remained the subject of much debate. The results of recent clinical trials on the use of antiplatelet therapy suggest that patients with a history of stroke or transient ischemic attack may constitute a population distinct from patients with coronary or peripheral vascular disease. This may be caused, in part, by the differing etiologies of stroke and the increased vulnerability of cerebral vessels to bleeding. Indeed, dual antiplatelet therapy, which has been found to be beneficial for the treatment of acute coronary syndromes and percutaneous coronary interventions, does not confer secondary stroke protection. The emerging paradigm is that some level of platelet inhibition is required for secondary stroke protection; a level beyond which increased risk of bleeding arises.

CONCLUSIONS

Because the vast majority of patients with ischemic stroke have recurrent stroke or transient ischemic attack, rather than myocardial infarction, as their next event, antiplatelet therapies for these patients should be administered according to what has been shown to be efficacious for secondary stroke protection rather than for myocardial protection. Combination therapies, which provide optimal platelet inhibition as well as vascular protection, may offer the best strategy for secondary stroke protection.

Prevention of vascular events in patients with cerebrovascular disease: efficacy and appropriate duration of antiplatelet therapy

Antiplatelet therapy has shown consistent benefit in the prevention of secondary stroke. The paucity of head-to-head studies of different antiplatelet regimens, assessment of comparative efficacy, and optimal treatment duration requires evaluation and comparison of clinical studies that vary extensively in design and follow-up. Evidence for aspirin benefit in secondary stroke prevention is strong, but existing studies provide little guidance with regard to treatment duration. The efficacy of clopidogrel in secondary event prevention is significantly greater than that of aspirin for patients with a history of peripheral artery disease, but does not differ from that of aspirin for patients with a history of stroke or myocardial infarction. Relative to clopidogrel alone, the addition of aspirin to clopidogrel results in increased risk for life-threatening bleeding episodes similar in absolute magnitude to the reduction of secondary event risk in patients with stroke. Benefits associated with clopidogrel occur early in the course of therapy; few data support clopidogrel use for longer than 1 year after stroke. Monotherapy with extended-release dipyridamole (ER-DP) provides reduction in secondary stroke risk similar to aspirin; however, the combination of aspirin plus ER-DP significantly reduces risk relative to either agent alone. Compared with placebo and monotherapy with either agent, risk reduction for the aspirin plus ER-DP combination continued through 24 months, with no concomitant increase in bleeding risk. Additional clinical studies should provide needed comparisons of efficacy and guidance with regard to optimal duration of therapy.

The action of dipyridamole to prevent thrombosis: practical implications for the treatment and prevention of stroke

Aggrenox (Boehringer Ingelheim, Ingelheim, Germany), a novel combination of low-dose aspirin with dipyridamole, represents a safe and promising combination alternative for mild but sustained platelet inhibition, and reduction of both arterial and venous thrombi occurrences. In a large, well-controlled randomized trial (ESPS-2 ) evaluating antiplatelet agents for stroke prevention, Aggrenox was twice as effective as monotherapy with either aspirin or dipyridamole. There is an increasing body of evidence that a delicate strategy with Aggrenox provides modest inhibition of platelet activity, especially in a chronic, long-term setting. Mild platelet inhibition beyond conventional aggregation may represent a substantial advantage over aggressive antiplatelet regimens for the treatment, and especially for secondary prevention, of cerebrovascular ischemic events. Although there is no doubt that the concept of inhibiting platelets is vital for the treatment of vascular ischemic disease in general and ischemic stroke and transient ischemic attack (TIA) in particular, the optimal degree of such inhibition still remains an unsolved mystery. It seems that the concepts of "the more, the better" and "one size fits all" may no longer be valid for ideal antiplatelet protection in such high-risk populations. Without routine individual laboratory assessment of platelet function, mild regimens have the advantage of being more suitable for the majority of patients and will contribute substantially to the success of dipyridamole. Conversely, if we can determine baseline platelet status and intelligently apply therapy based on platelet activity in each particular patient, clinical outcomes may be better. Avoiding excessive bleeding risks after aggressive strategies in patients with normal or already decreased platelet function, but targeting those who exhibit activated platelets, may improve risk stratification and save lives. Therefore, Aggrenox should be considered a drug of choice to prevent the second stroke. Eliminating, or at least minimizing, the most frequent side effect, namely transitory headaches at the beginning of therapy with Aggrenox, will benefit patients and increase the use of this agent. Should the PRoFESS (Prevention Regimen For Effectively avoiding Second Strokes) trial show an advantage in event reduction with Aggrenox over clopidogrel, the increase will be especially dramatic. In short, based on current evidence most guidelines include Aggrenox as a first-line option for secondary prevention of ischemic stroke or TIA, and some recent versions suggest it may be preferable in other clinical scenarios.

Dipyridamole for preventing stroke and other vascular events in patients with vascular disease

BACKGROUND

Patients with limited cerebral ischaemia of arterial origin are at risk of serious vascular events (4% to 11% annually). Aspirin reduces that risk by 13%. In one trial, adding dipyridamole to aspirin was associated with a 22% risk-reduction compared with aspirin alone. However, a systematic review of all trials of antiplatelet agents by the Antithrombotic Trialists' Collaboration showed that, in high-risk patients, there was virtually no difference between the aspirin-dipyridamole combination and aspirin alone.

OBJECTIVES

To assess the efficacy and safety of dipyridamole versus control in the secondary prevention of vascular events in patients with vascular disease.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (searched November 2005), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to November 2005) and EMBASE (1980 to November 2005).

SELECTION CRITERIA

Randomised long-term secondary prevention trials with concealed treatment allocation, treatment for more than one month, starting within six months after presentation of an arterial vascular disease were selected. Treatment consisted of dipyridamole with or without other antiplatelet drugs compared with no drug or an antiplatelet drug other than dipyridamole.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion, assessed trial quality and extracted data. Data were analysed according to the intention-to-treat principle.

MAIN RESULTS

Twenty-seven trials were included, with 20242 patients, among whom 1399 vascular deaths and 3090 fatal and non-fatal vascular events occurred during follow up. Compared with control, dipyridamole had no clear effect on vascular death (relative risk (RR) 1.02, 95% confidence internal (CI) 0.90 to 1.17). This result was not influenced by the dose of dipyridamole or type of presenting vascular disease. In the presence of aspirin, dipyridamole appeared to reduce the risk of vascular events compared with control (RR 0.90, 95% CI 0.82 to 0.97), due to a single large trial in patients presenting with cerebral ischaemia.

AUTHORS' CONCLUSIONS

For patients who presented with arterial vascular disease, there was no evidence that dipyridamole, in the presence or absence of another antiplatelet drug reduced the risk of vascular death, though it may reduce the risk of further vascular events. However, this benefit was found in only one single large trial and only in patients presenting after cerebral ischaemia. There was no evidence that dipyridamole alone was more efficacious than aspirin. Further trials comparing the effects of the combination of dipyridamole with aspirin versus aspirin alone are justified.

Carotid plaque composition in stable and unstable coronary artery disease

BACKGROUND

Several pieces of evidence suggest that formation of complex atheromatous plaques may be influenced not only by local but also by systemic factors.

METHODS

Twenty-five patients (16 men/9 women, age 63 +/- 10 years) with stable coronary artery disease (sCAD) and 61 (41 men/20 women, age 66 +/- 16 years) with acute coronary syndromes (ACSs) underwent carotid ultrasonography within 2 days of cardiac catheterization. Complex coronary plaques were associated with intraluminal filling defect consistent with thrombus, ulceration, or irregularity. Complex carotid plaques had one or more of the following features: (a) ulceration, (b) irregular surface, (c) mobile thrombi on plaque surface, (d) predominant echolucency, and (e) heterogeneity with intraplaque echolucent areas.

RESULTS

Carotid intimamedia thickness and luminal diameter were not significantly different between patients with sCAD and those with ACS (0.95 +/- 0.22 vs 1.0 +/- 0.15 mm [P = .23] and 6.1 +/- 0.89 vs 6.20 +/- 0.77 mm [P = .60], respectively), whereas the interadventitial diameter was slightly greater in the latter (7.93 +/- 1.05 vs 8.40 +/- 0.97 mm, P = .0496). Both complex coronary plaques and complex carotid plaques were more common in patients with ACS than in those with sCAD (n = 52 [85.2%] vs n = 6 [24%] [P < .0001] and n = 38 [62.3%] vs n = 5 [20%] [P = .0009], respectively). The odds of having complex carotid plaques were increased > 6-fold in patients with ACS compared with those with sCAD (OR 6.61, 95% CI 2.24-19.32).

CONCLUSIONS

Complex coronary plaques are associated with complex carotid plaques and the high prevalence of both plaque types in patients with ACS is indicative of a systemic process contributing to complex plaque formation and instability.

Modified-release dipyridamole combined with aspirin for secondary stroke prevention

Patients suffering from transient ischemic attack (TIA) or ischemic stroke have a high risk of suffering a first or recurrent stroke, with an annual risk of between 5 and 15%. The European Stroke Prevention Study (ESPS)2 was a randomized, double-blind, placebo-controlled trial involving 6602 patients with TIA or stroke comparing aspirin alone (50 mg daily), modified-release (MR) dipyridamole alone (200 mg twice daily), aspirin plus dipyridamole, and placebo. The 2-year relative risk reduction of stroke in the aspirin plus MR-dipyridamole group (37.0%) was significantly higher than in either the aspirin group (18.1%) or the MR-dipyridamole group (16.3%). The results of the comparison between aspirin plus MR-dipyridamole versus placebo confirmed the findings of ESPS1. The results of ESPS2 were at odds with all prior trials with dipyridamole alone or in association with aspirin, but it was also the only trial sufficiently powered to show a significant difference. For this reason, a meta-analysis was performed based on a systematic review of individual patient data from randomized controlled trials involving dipyridamole in patients with prior ischemic stroke or TIA. Recurrent stroke was reduced by dipyridamole compared with placebo, and by combined aspirin and dipyridamole versus aspirin alone, dipyridamole alone or placebo. In two post hoc analyses the efficacy of aspirin plus extended-release dipyridamole was compared with aspirin alone for the prevention of recurrent stroke among high-risk groups. Stroke models from the Framingham Study and the Stroke Prognostic Instrument II were applied to subjects in ESPS2 to assign patients to risk groups. Compared with aspirin alone, aspirin plus MR-dipyridamole demonstrated a more pronounced efficacy in reducing the risk for stroke and vascular events among patients younger than 70 years of age, with hypertension, or prior stroke; current smokers; and those with any prior cardiovascular disease. Another model (Essen risk score) showed that patients with a high risk of recurrent stroke show a much greater benefit from aspirin plus MR-dipyridamole compared with aspirin monotherapy than patients with a low risk.

Diagnosis and prevention of atherosclerotic cerebral infarction

Atherosclerotic disease accounts for approximately 25% of ischemic strokes. Atherosclerotic stroke is caused mainly by embolic events from the carotid artery bifurcation or the aortic arch, although intracranial thrombosis can occur, more often in African Americans, Asians, and diabetes patients. Primary prevention of stroke is critical for patients with risk factors for atherosclerosis, including hypertension, diabetes, smoking and hypercholesterolemia. Stroke can be prevented in patients with established atherosclerotic disease by identification and management of patients with carotid artery stenosis by non-invasive testing. Particular attention must be paid to patients with transient symptoms of brain ischemia.

Efficacy and costs of secondary prevention with antiplatelets after ischaemic stroke

Ischaemic stroke and other atherothrombotic events substantially increase the medico-economic burden because of their high treatment costs and long-lasting disabilities with need for chronic care. Studies have shown that the cost of stroke represents approximately 3 - 5% of the annual health budget. Antiplatelet agents play a major role in secondary stroke prevention. Acetylsalicylic acid (ASA), ASA combined with extended-release dipyridamole (ER-Dip), and clopidogrel are all acceptable choices for first-line treatment in the secondary prevention of stroke. The newer antiplatelets, however, are more expensive than ASA, and their cost-effectiveness is not easily estimated. ASA has to be given to 33 stroke patients to prevent one future stroke, myocardial infarction (MI) or vascular death compared with placebo. Adding ER-Dip to ASA increases the benefit for the patients. A total of 33 stroke patients had to be treated with this combination, instead of ASA, to prevent one stroke. However, the combination of ASA plus ER-Dip does not prevent MI, vascular death or the combined end point of either stroke or death. Clopidogrel is more effective than ASA in preventing a combined end point of ischaemic stroke, MI, or vascular death, but it has not been shown to be superior to ASA in preventing recurrent stroke in transient ischaemic attack or stroke patients. Several subgroups, such as stroke patients with additional peripheral artery disease, patients with prior coronary artery bypass, patients with insulin-dependent diabetes, and patients with recurrent vascular events, were identified, in whom the benefit of clopidogrel is amplified. Taking economical aspects into account, the fixed combination of ASA and ER-Dip can be recommended for secondary stroke prevention as a first-line alternative to ASA in patients without major comorbidity. In patients with higher comorbidity, clopidogrel may be more effective for the individual patient compared with ASA, and might also be cost-effective. Furthermore, in patients with ASA intolerance clopidogrel is a useful, but expensive, alternative.

Adverse Effects and Drug Interactions of Antithrombotic Agents Used in Prevention of Ischaemic Stroke

Stroke is the third most common cause of death in the US. Primary prevention of stroke can be achieved by control of risk factors including hypertension, diabetes mellitus, elevated cholesterol levels and smoking. Approximately one-third of all ischaemic strokes occur in patients with a history of stroke or transient ischaemic attack (TIA). The mainstay of secondary prevention of ischaemic stroke is the addition of medical therapy with antithrombotic agents to control the risk factors for stroke. Antithrombotic therapy is associated with significant medical complications, particularly bleeding.Low-dose aspirin (acetylsalicylic acid) has been shown to be as effective as high-dose aspirin in the prevention of stroke, with fewer adverse bleeding events. Aspirin has been shown to be as effective as warfarin in the prevention of noncardioembolic ischaemic stroke, with significantly fewer bleeding complications. Ticlopidine may be more effective in preventing stroke than aspirin, but is associated with unacceptable haematological complications. Clopidogrel may have some benefit over aspirin in preventing myocardial infarction, but has not been shown to be superior to aspirin in the prevention of stroke. The combination of clopidogrel and aspirin may be more effective than aspirin alone in acute coronary syndromes, but the incidence of adverse bleeding is significantly higher. Furthermore, the combination of aspirin with clopidogrel has not been shown to be more effective for prevention of recurrent stroke than clopidogrel alone, while the rate of bleeding complications was significantly higher with combination therapy. The combination of aspirin and extended-release dipyridamole has been demonstrated to be more effective than aspirin alone, with the same rate of adverse bleeding complications as low-dose aspirin. When selecting the appropriate antithrombotic agent for secondary prevention of stroke, the adverse event profile of the drug must be taken into account when assessing the overall efficacy of the treatment plan.