Ticlopidine versus aspirin for the prevention of recurrent stroke. Analysis of patients with minor stroke from the Ticlopidine Aspirin Stroke Study

Antiplatelet therapy and outcomes after aneurysmal subarachnoid hemorrhage: A systematic review and meta-analysis

BACKGROUND

The efficacy of antiplatelet therapy (APT) after aneurysmal subarachnoid hemorrhage (aSAH) remains unclear. We performed a systematic review and meta-analysis to summarize the associations of APT use after aSAH with outcomes.

METHODS

We searched published medical literature to identify cohort studies involving adults with aSAH. The exposure was APT use after aSAH. Outcome measures were good functional outcome (modified Rankin Score 0-2 or Glasgow Outcome Scale 4-5), delayed cerebral ischemia (infarcts on neuroimaging), and intracranial hemorrhage. After assessing study heterogeneity and publication bias, we performed a meta-analysis using random-effects models to assess the strength of association between APT and SAH outcomes.

RESULTS

A total of 14 studies with 4228 aSAH patients were included. APT after aSAH was associated with good functional outcome (pooled relative risk, 1.08; 95% confidence interval, [CI], 1.02-1.15; I2 = 45%, p for heterogeneity = 0.04), but there was no relationship with delayed cerebral ischemia (pooled relative risk, 0.80; 95% confidence interval, [CI], 0.63-1.02; I2 = 61%, p for heterogeneity <0.01) or intracranial hemorrhage (pooled relative risk, 1.50; 95% confidence interval, [CI], 0.98-2.31; I2 = 0, p for heterogeneity =0.71). In additional analyses, APT resulted in good functional outcomes in endovascularly-treated patients. When stratified by type of medication, aspirin, clopidogrel, and ticlopidine were associated with good functional outcomes.

CONCLUSIONS

APT after aSAH was associated with a modest improvement in functional outcome, but there was no relationship with delayed cerebral ischemia or intracranial hemorrhage.

Antiplatelets and Vascular Dementia: A Systematic Review

Vascular dementia (VD) is a neurocognitive disorder whose precise definition is still up for debate. VD generally refers to dementia that is primarily caused by cerebrovascular disease or impaired cerebral blood flow. It is a subset of vascular cognitive impairment, a class of diseases that relate any cerebrovascular injury as a causal or correlating factor for cognitive decline, most commonly seen in the elderly. Patients who present with both cognitive impairment and clinical or radiologic indications of cerebrovascular pathology should have vascular risk factors, particularly hypertension, examined and treated. While these strategies may be more effective at avoiding dementia than at ameliorating it, there is a compelling case for intensive secondary stroke prevention in these patients. Repeated stroke is related to an increased chance of cognitive decline, and poststroke dementia is connected with an increased risk of death. In general, most physicians follow recommendations for secondary stroke prevention in patients with VD, which can be accomplished by the use of antithrombotic medicines such as antiplatelets (aspirin, clopidogrel, ticlopidine, cilostazol, etc.). In individuals with a high risk of atherosclerosis and those with documented symptomatic cerebrovascular illness, antiplatelets treatment lowers the risk of stroke. While this therapy strategy of prevention and rigorous risk management has a compelling justification, there is only limited and indirect data to support it. The following systematic review examines the role of antiplatelets in the management of vascular dementia in published clinical trials and studies and comments on the current evidence available to support their use and highlights the need for further study.

Treatment Approaches to Lacunar Stroke

Lacunar strokes are appropriately named for their ability to cavitate and form ponds or "little lakes" (Latin: lacune -ae meaning pond or pit is a diminutive form of lacus meaning lake). They account for a substantial proportion of both symptomatic and asymptomatic ischemic strokes. In recent years, there have been several advances in the management of large vessel occlusions. New therapies such as non-vitamin K antagonist oral anticoagulants and left atrial appendage closure have recently been developed to improve stroke prevention in atrial fibrillation; however, the treatment of small vessel disease-related strokes lags frustratingly behind. Since Fisher characterized the lacunar syndromes and associated infarcts in the late 1960s, there have been no therapies specifically targeting lacunar stroke. Unfortunately, many therapeutic agents used for the treatment of ischemic stroke in general offer only a modest benefit in reducing recurrent stroke while adding to the risk of intracerebral hemorrhage and systemic bleeding. Escalation of antithrombotic treatments beyond standard single antiplatelet agents has not been effective in long-term lacunar stroke prevention efforts, unequivocally increasing intracerebral hemorrhage risk without providing a significant benefit. In this review, we critically review the available treatments for lacunar stroke based on evidence from clinical trials. For several of the major drugs, we summarize the adverse effects in the context of this unique patient population. We also discuss the role of neuroprotective therapies and neural repair strategies as they may relate to recovery from lacunar stroke.

Incidence of neutropenia in patients with ticlopidine/Ginkgo biloba extract combination drug for vascular events: A post-marketing cohort study

BACKGROUND AND PURPOSE

The ticlopidine/Ginkgo biloba ext. combination drug (Yuclid) is used as an antiplatelet agent for prevention of vascular events since its approval in 2008. The purpose of this study is to explore the safety of ticlopidine/Ginkgo biloba combination, mainly regarding the incidence of neutropenia, through a post-marketing surveillance study.

METHODS

From March 2009 to October 2015, a total of 4839 subjects had been enrolled in this study. The enrollments were conducted by 152 doctors of 89 hospitals according to the regulations for post-marketing surveillance programs in Korea. If a subject was administered the drug once, he/she was included in the safety analysis set for any adverse events and bleedings, and the primary safety evaluation regarding neutropenia was conducted in subjects who completed 3-month blood test follow-up. We predefined that 1% reduction in neutropenia incidence by ticlopidine/Ginkgo biloba ext. combination from the previously reported incidence of ticlopidine of 2.3% was clinically meaningful.

RESULTS

Among the safety analysis set of 4831 patients (99.8% of the enrolled subjects), 3150 (65.1%) completed evaluation for neutropenia at 3 months which is the primary safety endpoint. The major causes of dropout were no follow-up visit at 3 months (n = 1016) and violation of the follow-up period (n = 503). Nine patients experienced neutropenia (Absolute neutrophil count [ANC] ≤ 1200mm3) and the estimated cumulative incidence at 3 months is 0.29% (95% confidence interval, 0.13%- 0.54%). Severe neutropenia (ANC ≤ 450mm3) did not occur in any patients.

CONCLUSIONS

The incidence of neutropenia with addition of Ginkgo biloba ext. to ticlopidine may be lower than the previously reported incidence of neutropenia with ticlopidine, which needs to be confirmed in randomized controlled trials.

Secondary Prevention of Ischemic Cerebrovascular Disease. What Is the Evidence?

Patients who had a transient ischemic attack or stroke are at increased risk of experiencing recurrent cerebrovascular events. For this reason, secondary prevention of ischemic cerebrovascular disease is essential. Several modifiable, lifestyle-associated risk factors have been implicated, such as physical activity, smoking, and alcohol consumption. Established and emerging vascular risk factors are associated with an increased risk of stroke. Pharmacologic treatment, including the use of antiplatelet, antihypertensive, and lipid-lowering agents, has also been shown to reduce the risk of secondary cerebrovascular events. Surgical intervention, either open or endovascular, may be the preferred therapeutic option in well-defined subsets of patients. It is important to establish specific measures for the early detection and prevention of recurrent cerebrovascular disease. Therefore, further research and greater awareness in this field are needed.

Adenosine-diphosphate (ADP) receptor antagonists for the prevention of cardiovascular disease in type 2 diabetes mellitus

BACKGROUND

Cardiovascular disease (CVD) is the most prevalent complication of type 2 diabetes with an estimated 65% of people with type 2 diabetes dying from a cause related to atherosclerosis. Adenosine-diphosphate (ADP) receptor antagonists like clopidogrel, ticlopidine, prasugrel and ticagrelor impair platelet aggregation and fibrinogen-mediated platelet cross-linking and may be effective in preventing CVD.

OBJECTIVES

To assess the effects of adenosine-diphosphate (ADP) receptor antagonists for the prevention of cardiovascular disease in type 2 diabetes mellitus.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (issue 2, 2011), MEDLINE (until April 2011) and EMBASE (until May 2011). We also performed a manual search, checking references of original articles and pertinent reviews to identify additional studies.

SELECTION CRITERIA

Randomised controlled trials comparing an ADP receptor antagonist with another antiplatelet agent or placebo for a minimum of 12 months in patients with diabetes. In particular, we looked for trials assessing clinical cardiovascular outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data for studies which fulfilled the inclusion criteria, using standard data extraction templates. We sought additional unpublished information and data from the principal investigators of all included studies.

MAIN RESULTS

Eight studies with a total of 21,379 patients with diabetes were included. Three included studies investigated ticlopidine compared to aspirin or placebo. Five included studies investigated clopidogrel compared to aspirin or a combination of aspirin and dipyridamole, or compared clopidogrel in combination with aspirin to aspirin alone. All trials included patients with previous CVD except the CHARISMA trial which included patients with multiple risk factors for coronary artery disease. Overall the risk of bias of the trials was low. The mean duration of follow-up ranged from 365 days to 913 days.Data for diabetes patients on all-cause mortality, vascular mortality and myocardial infarction were only available for one trial (355 patients). This trial compared ticlopidine to placebo and did not demonstrate any statistically significant differences for all-cause mortality, vascular mortality or myocardial infarction. Diabetes outcome data for stroke were available in three trials (31% of total diabetes participants). Overall pooling of two (statistically heterogeneous) studies showed no statistically significant reduction in the combination of fatal and non-fatal stroke (359/3194 (11.2%) versus 356/3146 (11.3%), random effects odds ratio (OR) 0.81; 95% confidence interval (CI) 0.44 to 1.49) for ADP receptor antagonists versus other antiplatelet drugs. There were no data available from any of the trials on peripheral vascular disease, health-related quality of life, adverse events specifically for patients with diabetes, or costs.

AUTHORS' CONCLUSIONS

The available evidence for ADP receptor antagonists in patients with diabetes mellitus is limited and most trials do not report outcomes for patients with diabetes separately. Therefore, recommendations for the use of ADP receptor antagonists for the prevention of CVD in patients with diabetes are based on available evidence from trials including patients with and without diabetes. Trials with diabetes patients and subgroup analyses of patients with diabetes in trials with combined populations are needed to provide a more robust evidence base to guide clinical management in patients with diabetes.

Aspirin "failures," clopidogrel added to aspirin, and secondary stroke prevention in veterans presenting with TIA or mild-to-moderate ischemic stroke

Our objective was to investigate whether clopidogrel added to low-dose aspirin reduced vascular events in male patients at our VA hospital who had "failed" aspirin therapy because of a mild-to-moderate stroke or a transient ischemic attack. Of 179 consecutive patients who both reported daily aspirin usage at the time of their newest ischemic event as well as were then operationally defined as aspirin "failures," 134 (group A) were treated with combined aspirin-clopidogrel, 15 (group B) underwent an early arterial procedure, 25 (group C) were anticoagulated, and 5 were not entered or continued because of either non-compliance or a refusal to participate. Study therapies were modified because of a vascular event in 4.5% of group A (one non-fatal ischemic stroke, one non-fatal myocardial infarction, and four transient ischemic attacks) and 33% of group B (one non-fatal ischemic stroke, one non-fatal myocardial infarction, and three transient ischemic attacks). No major or fatal bleeding events occurred in any of those on combined aspirin-clopidogrel therapy, with minor bleeding in 10 of 134 (7.5%) and 2 of 15 (13.3%) of group A and B patients, respectively. Patients were followed for 18 +/- 9.7 months. Combined aspirin-clopidogrel therapy appears both safe as well as effective in this single-center, observational study.

Current and future concepts in stroke prevention

Stroke is a major cause of morbidity and mortality in an aging population. The current understanding of the pathophysiology of atherosclerotic diseases, the most common cause of stroke, and the evidence for existing therapeutic interventions for the prevention of stroke are presented. Specifically, we review the evidence for antiplatelet agents, anticoagulants, antihypertensive medications, lipid-lowering agents and carotid endarterectomy for stroke prevention.

Stroke prevention in the elderly

The incidence of stroke and risk factors peak in subjects > or = 75 years. Highest risk patients benefit most from effective therapy. For this reason, all strategies of proven value in stroke prevention must be assiduously applied. Control of hypertension, hyperlipidemia, diabetes mellitus and cessation of cigarette smoking are obligatory at all ages but are of special importance in the elderly. Antithrombotic drugs have been proven beneficial for patients at high risk. Lower risk subjects, including those with asymptomatic carotid artery disease, gain no proven benefit from anti-platelet drugs. Patients with non-valvular atrial fibrillation (NVAF), a condition that increases with age, require anticoagulant therapy. Strict regulation of the INR is required otherwise aspirin is recommended. Without evidence of organ failure, elderly patients with severely stenotic symptomatic carotid artery disease should receive endarterectomy. They benefit most. The evidence for benefit from endarterectomy in asymptomatic subjects at any age is weak and cannot be recommended.

Piracetam versus acetylsalicylic acid in secondary stroke prophylaxis. A double-blind, randomized, parallel group, 2 year follow-up study

Piracetam has been shown to inhibit platelet aggregation. Therefore, we performed a double-blind, randomized, parallel group study to compare the efficacy of daily 1600 mg piracetam t.i.d. vs. 200 mg acetylsalicylic acid (ASA) t.i.d. in secondary stroke prophylaxis. 563 patients after stroke as confirmed by computed tomography (CT) or magnetic resonance imaging (MRI) were enrolled and received either piracetam or ASA during a 2 year follow-up period. The primary endpoint was the rate of stroke, transient ischaemic attack (TIA), or death from vascular cause. The secondary endpoint was the rate of adverse events leading to a premature discontinuation of the study medication. Patients were visited at home every 3 months and were examined in hospital after 1 and 2 years. At every visit, the platelet function was evaluated. No significant difference and no significant equivalence could be shown for the primary endpoint between the piracetam and the ASA group both in the intention-to-treat and in the per-protocol analysis. However, there was a not significant trend in favor of ASA (11.7 vs. 15.2%). After excluding those patients who did not respond to antiplatelet medication in vitro, however, piracetam and ASA were equivalent in secondary stroke prophylaxis (stroke, TIA, or vascular death 10.1% in the piracetam group vs. 9.7% in the ASA group). Piracetam was significantly superior to ASA in the secondary endpoint (P=0.0039). The data suggest that the overall efficacy of piracetam in secondary stroke prophylaxis is not as good as that of ASA but that piracetam is better tolerated. However, our data furthermore show that nonresponders to pharmacological inhibition of platelet function are more frequent under piracetam therapy and that they may influence the results of large studies on secondary prophylaxis in vascular diseases.

Value of antiplatelet therapy in preventing thrombotic events in generalized vascular disease

Atherothrombosis is the major underlying cause of acute coronary syndromes, ischemic stroke, and peripheral artery disease, and thus is the leading cause of death and disability in Western countries. Platelet inhibitors play a major role in preventing these ischemic complications. There is strong evidence from the Antiplatelet Trialists' Collaboration meta-analysis that aspirin reduces the combined risk of stroke, myocardial infarction (MI), or vascular death in atherosclerotic patients. The Ticlopidine Aspirin Stroke Study (TASS) compared aspirin and ticlopidine in the secondary prevention of high-risk patients after ischemic stroke and demonstrated a significant advantage for ticlopidine over aspirin. In peripheral arterial disease, the Swedish Ticlopidine Multicentre Study (STIMS) showed that ticlopidine was very effective against placebo. Intravenous antiplatelet agents, such as abciximab, tirofiban, and eptifibitide were also proven effective in acute coronary syndromes and unstable angina. In the Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events (CAPRIE) trial, clopidogrel was compared with aspirin in patients with symptomatic atherothrombosis regardless of the initial localization of the ischemic event (coronary, cerebral, or peripheral). The efficacy of clopidogrel based on the first occurrence of ischemic stroke, MI, or vascular death showed a relative risk reduction of 8.7% over and above the 25% reduction currently accepted with aspirin (p < 0.05). The greatest benefit of clopidogrel was in the reduction of fatal and nonfatal MI in the most severe groups of patients, providing a 19% relative risk reduction (p = 0.008). The recent disappointing results obtained with oral glycoprotein IIb/IIIa receptor blocking agents may emphasize the need for other antiplatelet combination therapy, such as aspirin-clopidogrel, in coronary disease, stents, stroke, and possibly atherothrombosis in high-risk patients.

[Bone marrow aplasia related to ticlopidine]

The authors report two cases of bone marrow aplasia observed 2 months after initiation of a treatment with ticlopidine. The outcome was favorable after discontinuation of therapy. The frequency of this severe drug-induced complication seems to have been underestimated. The absolute necessity of a careful haematological survey during the first 3 months of therapy is pointed out.

Drugs and surgery in the prevention of ischemic stroke

Randomized clinical trials have proved that warfarin therapy decreases the risk of stroke in patients with nonvalvular atrial fibrillation and in those who have had a myocardial infarction. In patients who are not candidates for long-term anticoagulant therapy, aspirin is beneficial, but the reduction in risk is smaller with aspirin than with warfarin. In patients with cerebral ischemic symptoms of noncardiac origin, aspirin and ticlopidine reduce the risk of stroke, but the benefit is modest. Given alone, neither dipyridamole nor sulfinpyrazone prevents stroke. The question remains whether either of these drugs plus aspirin is better than aspirin alone. The optimal dose of aspirin for stroke prevention has not been established. Carotid endarterectomy reduces the risk of stroke in symptomatic patients with at least 70 percent stenosis, as determined by arteriography. Current trials are addressing the question of whether endarterectomy is beneficial for patients with moderate degrees of carotid stenosis. The benefit of endarterectomy for patients with asymptomatic carotid lesions remains unclear.

Ticlopidine and fatal aplastic anemia in an elderly woman

OBJECTIVE

To report a case of aplastic anemia that developed during ticlopidine treatment.

CASE SUMMARY

An 84-year-old woman was started on ticlopidine for secondary stroke prevention. Within six weeks of initiating ticlopidine therapy she developed aplastic anemia. She was hospitalized and received empiric antibiotics, antifungal agents, blood transfusions, platelets, and granulocyte colony-stimulating factor. The patient died on day 76 after beginning ticlopidine.

DISCUSSION

Hematologic effects such as neutropenia, thrombocytopenia, agranulocytosis, thrombotic thrombocytopenic purpura, and pancytopenia have been described with the use of ticlopidine. Previous case reports have associated ticlopidine with the development of aplastic anemia.

CONCLUSIONS

Ticlopidine can produce fatal hematologic adverse effects, and its use should be reserved as second-line therapy.

Platelet thromboembolism

Platelet-dependent thrombosis and subsequent embolization are major causes of cerebral ischaemia. Beside aspirin which irreversibly blocks platelet cyclo-oxygenase, several other substances interfere in different platelet metabolic pathways and block platelet adhesion and aggregation. We found in an experimental model using non-human primates that a specific peptide inhibitor blocking GP IIb/IIIa platelet receptor which binds fibrinogen completely, prevents the retention of embolized platelet aggregates in the cerebral circulation. As thrombin may play a key role for platelet activation in vivo leech-derived hirudin, a direct thrombin inhibitor as well as activated protein C which limits thrombin production and also prevents platelet dependent thrombus formation very effective. We demonstrated in the same non-human primate model of platelet embolization that the amount of retention of platelet emboli in the vascular bed depends on the nature of the vasculature. For example, platelet emboli were cleared very quickly from brain microcirculation, whereas platelet embolization into the lower limb via the femoral artery caused a significantly longer retention of the embolized material. Such specific mechanisms may be caused by different levels of local vasodilators as PGI2 or EDRF.

The prevention of cardiovascular disease. Emphasis on secondary prevention

Atherosclerosis is a progressive disease affecting all major arteries. Clinical evidence of atherosclerosis increases the risk of subsequent morbid and mortal events fivefold to sevenfold over the next 5 to 10 years. The same risk factors contribute to the initial development of CVD events as to their recurrence. Both coronary and noncoronary events, such as stroke or PAD, reflect the severity of the underlying atherosclerotic process and strongly predict future excess CVD morbidity and mortality. Short-term and long-term survival depends on modifying the risk factors that contribute to CVD events. Although absolute proof of benefit for secondary prevention does not exist for all risk factors, the data from primary prevention trials and the secondary prevention trials that have been done argue strongly for aggressive intervention. Benefit has been demonstrated for smoking cessation, cholesterol reduction, and blood pressure control. Selected patients may benefit from additional medical, procedural, or surgical interventions to prolong life, such as beta-blocking agents, aspirin, or carotid endarterectomy. Many secondary prevention measures are a cost-effective way to reduce the substantial morbidity and mortality due to CVD. Contrary to primary prevention, even modest treatment effects from secondary prevention efforts can benefit large numbers of patients. Finally, secondary prevention may be more successful because patients with clinical evidence of CVD may be more highly motivated than their healthy counterparts to make and maintain lifestyle changes.

Two-year follow-up of aspirin responder and aspirin non responder. A pilot-study including 180 post-stroke patients

Aspirin is proposed to be effective in stroke-prophylaxis because it completely inhibits the platelet prostanoid-pathway. In about 90% of stroke victims, increased platelet reactivity (PR) can be reduced to the normal range by aspirin. Twelve hours later, about one third of them show an enhanced PR again. These patients are called secondary aspirin non responders (SANR). In this study the potential pathogenetic and prognostic impact of this biological feature on stroke recurrence was evaluated. Before discharge from the hospital, PR was determined 12 hours after an oral administration of 500 mg aspirin in 180 patients aged 58 +/- 15 years; 74 were female and 106 male. All had suffered a stroke in the internal carotid artery territory. Patients were treated with 3 x 500 mg aspirin/d and were followed up over a 24-month period. Major endpoints of this study were stroke, myocardial infarction or vascular death. On discharge from the hospital, 120 of the 180 patients showed a normal PR under aspirin treatment. High test values were found in 60 patients (SANR). Six patients were lost for follow-up. Because of side effects 36 (20%) of the 180 patients enrolled discontinued medication. Major endpoints occurred in 4 of these 36 patients (11%) and in 25 of the 138 remaining patients (18.1%); 19 patients died in consequence of a vascular event during the observation period. Major endpoints were seen in only 5 of 114 (4.4%) of the aspirin responders, but in 24 out of 60 SANR (40%, p < 0.0001). It may be assumed that early identification of SANR's is a clinically useful tool to classify patients at high risk for recurrence of vascular events.