Aspirin or Anticoagulants in Stenosis of the Middle Cerebral Artery:A Randomized Trial

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 guidelines on treatment of patients with intracranial atherosclerotic disease

The aim of the present European Stroke Organisation guideline is to provide clinically useful evidence-based recommendations on the management of patients with intracranial atherosclerotic disease (ICAD). The guidelines were prepared following the Standard Operational Procedure of the European Stroke Organisation guidelines and according to GRADE methodology. ICAD represents a major cause of ischemic stroke worldwide, and patients affected by this condition are exposed to a high risk for future strokes and other major cardiovascular events, despite best medical therapy available. We identified 11 relevant clinical problems affecting ICAD patients and formulated the corresponding Population Intervention Comparator Outcomes (PICO) questions. The first two questions refer to the asymptomatic stage of the disease, which is being increasingly detected thanks to the routine use of noninvasive vascular imaging. We were not able to provide evidence-based recommendations regarding the optimal detection strategy and management of asymptomatic ICAD, and further research in the field is encouraged as subclinical ICAD may represent a big opportunity to improve primary stroke prevention. The second block of PICOs (3-5) is dedicated to the management of acute large vessel occlusion (LVO) ischemic stroke caused by ICAD, a clinical presentation of this disease that is becoming increasingly relevant and problematic, since it is associated with more refractory endovascular reperfusion procedures. An operational definition of probable ICAD-related LVO is proposed in the guideline. Despite the challenging context, no dedicated randomized clinical trials (RCTs) were identified, and therefore the guideline can only provide with suggestions derived from observational studies and our expert consensus, such as the escalated use of glycoprotein IIb-IIIa inhibitors and angioplasty/stenting in cases of refractory thrombectomies due to underlying ICAD. The last block of PICOs is devoted to the secondary prevention of patients with symptomatic ICAD. Moderate-level evidence was found to recommend against the use of oral anticoagulation as preferred antithrombotic drug, in favor of antiplatelets. Low-level evidence based our recommendation in favor of double antiplatelet as the antithrombotic treatment of choice in symptomatic ICAD patients, which we suggest to maintain during 90 days as per our expert consensus. Endovascular therapy with intracranial angioplasty and or stenting is not recommended as a treatment of first choice in high-grade symptomatic ICAD (moderate-level evidence). Regarding neurosurgical interventions, the available evidence does not support their use as front line therapies in patients with high-grade ICAD. There is not enough evidence as to provide any specific recommendation regarding the use of remote ischemic conditioning in ICAD patients, and further RCTs are needed to shed light on the utility of this promising therapy. Finally, we dedicate the last PICO to the importance of aggressive vascular risk factor management in ICAD, although the evidence derived from RCTs specifically addressing this question is still scarce.

Antithrombotic treatment in patients with stroke and supracardiac atherosclerosis

OBJECTIVE

To compare the efficacy and safety of oral anticoagulants vs antiplatelets in patients with stroke and atherosclerotic plaques in the aortic arch or cervical or intracranial arteries, collectively described as supracardiac atherosclerosis.

METHODS

We searched PubMed and Scopus until August 28, 2019, for randomized trials comparing oral anticoagulants vs antiplatelets in patients with stroke and supracardiac atherosclerosis using the terms "anticoagulant or anticoagulation" and "antiplatelet or aspirin" and "randomized controlled trial or RCT" and "stroke or cerebral ischemia" and "aortic or carotid or vertebrobasilar or intracranial or atherosclerosis or stenosis or arterial." Four outcomes were assessed: recurrent ischemic stroke, major ischemic event or death, major bleeding, and intracranial bleeding. Treatment effects (relative risk [RR] and 95% confidence interval [CI]) were estimated by meta-analysis using random-effects models.

RESULTS

Among 1,117 articles identified in the literature search, results from 10 randomized controlled trials involving 6,068 patients with stroke/TIA with supracardiac atherosclerosis were included in the meta-analysis. Recurrent ischemic stroke rates were 2.94 per 100 patient-years in the anticoagulant-assigned patients vs 3.30 per 100 patient-years in the antiplatelet-assigned patients (RR, 0.91; 95% CI, 0.70-1.18 for the SJ estimator, I² = 26%). Major ischemic event or death rates were 4.39 per 100 patient-years in anticoagulant-assigned patients vs 4.32 in antiplatelet-assigned patients (RR, 1.03; 95% CI, 0.79-1.35; I² = 54.5%). Major bleeding rates were 2.88 per 100 patient-years in anticoagulant-assigned patients vs 0.82 in antiplatelet-assigned patients (RR, 3.21; 95% CI, 1.96-5.24; I² = 46%).

CONCLUSION

This systematic review and meta-analysis showed that anticoagulant-assigned patients with stroke and supracardiac atherosclerosis were not at different risk of ischemic stroke recurrence and increased risk of major bleeding compared to antiplatelet-assigned patients.

Medical and endovascular treatments of symptomatic intracranial stenosis. A Bayesian network meta-analysis

Intracranial stenosis is a well-established stroke risk factor with an increase of stroke recurrence or TIA up to 12.6% at 1 year. Treatments are different: medical and endovascular. We performed a multiple treatment comparison analysis to detect the best treatment in reducing the risk of stroke recurrence. We searched in Medline, Embase, Cochrane Central Register of Controlled Trials databases between 1979 and October 2017. Inclusion criteria were prospective randomized trials that evaluated patients with TIA or stroke due to intracranial stenosis and treated with different medical therapies and/or endovascular procedures. Primary endpoint was the recurrence of TIA or stroke in the territory of intracranial stenosis, while secondary endpoint was represented by any stroke or vascular death. Multiple treatment comparison meta-analysis based on a Bayesian fixed and random effects Poisson model was performed. Seven trials were included with a total of 1337 patients. At multiple treatment comparison, no significant differences between treatments were observed for both primary (median fixed effect standard OR: 0.40; 95%CI: 0.02-1.07) and secondary endpoints (median random effect standard OR: 1.17; 95%CI: 0.32-1.92). Treatment with aspirin alone ranked with high values both for primary and secondary endpoints (surface under the cumulative ranking curve of 70% and 82%, respectively). In patients with symptomatic intracranial stenosis, no differences between treatments were observed. However, aspirin alone was more effective than stenting in the reduction of TIA or stroke recurrences, with a better safety profile than oral anticoagulants.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

Vitamin K antagonists versus antiplatelet therapy after transient ischaemic attack or minor ischaemic stroke of presumed arterial origin

BACKGROUND

People who have had a transient ischaemic attack (TIA) or non-disabling ischaemic stroke have an annual risk of major vascular events of between 4% and 11%. Aspirin reduces this risk by 20% at most. Secondary prevention trials after myocardial infarction indicate that treatment with vitamin K antagonists is associated with a risk reduction approximately twice that of treatment with antiplatelet therapy.

OBJECTIVES

To compare the efficacy and safety of vitamin K antagonists and antiplatelet therapy in the secondary prevention of vascular events after cerebral ischaemia of presumed arterial origin.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched 15 September 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3), MEDLINE (2008 to September 2011) and EMBASE (2008 to September 2011). In an effort to identify further relevant trials we searched ongoing trials registers and reference lists. We also contacted authors of published trials for further information and unpublished data.

SELECTION CRITERIA

Randomised trials of oral anticoagulant therapy with vitamin K antagonists (warfarin, phenprocoumon or acenocoumarol) versus antiplatelet therapy for long-term secondary prevention after recent transient ischaemic attack or minor ischaemic stroke of presumed arterial origin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data.

MAIN RESULTS

We included eight trials with a total of 5762 participants. The data showed that anticoagulants (in any intensity) are not more efficacious in the prevention of vascular events than antiplatelet therapy (medium intensity anticoagulation: relative risk (RR) 0.80, 95% confidence interval (CI) 0.56 to 1.14; high intensity anticoagulation: RR 1.02, 95% CI 0.49 to 2.13). There is no evidence that treatment with low intensity anticoagulation gives a higher bleeding risk than treatment with antiplatelet agents: RR 1.27 (95% CI 0.79 to 2.03). However, it was clear that medium and high intensity anticoagulation with vitamin K antagonists, with an INR of 2.0 to 4.5, were not safe because they yielded a higher risk of major bleeding complications (medium intensity anticoagulation: RR 1.93, 95% CI 1.27 to 2.94; high intensity anticoagulation: RR 9.0, 95% CI 3.9 to 21).

AUTHORS' CONCLUSIONS

For the secondary prevention of further vascular events after TIA or minor stroke of presumed arterial origin, there is sufficient evidence to conclude that vitamin K antagonists in any dose are not more efficacious than antiplatelet therapy and that medium and high intensity anticoagulation leads to a significant increase in major bleeding complications.

Update on the natural history of intracranial atherosclerotic disease: A critical review

Intracranial atherosclerotic disease (ICAD) contributes to a significant number of ischemic strokes. There is debate in the recent literature concerning the impact of the location of stenosis in ICAD on outcome. Some reports have suggested that disease processes and outcomes vary by vessel location, potentially altering the natural history and indications for intervention. Here we have performed a comprehensive, critical review of the natural history of ICAD by vessel in an attempt to assess the differences in disease specific to each of the vascular territories. Our assessment concludes that only minor differences exist between patients with different vessels affected in vessel-specific ICAD. We have found that middle cerebral artery disease confers a lower mortality than vessel-specific ICAD in other intracranial vessels, asymptomatic disease follows a more benign course than symptomatic disease, and that plaque progression or the detection of microemboli on transcranial Doppler may predict poor outcome. Given the expanding indications for treatment of ICAD and rapidly developing endovascular techniques to confront this disease, a thorough understanding of the natural history of ICAD aids the interventional neuroradiologist in determining when to treat and how to predict outcome in this patient population.

Anticoagulants for preventing recurrence following presumed non-cardioembolic ischaemic stroke or transient ischaemic attack

BACKGROUND

After a first ischaemic stroke, further vascular events due to thromboembolism are common and often fatal. Anticoagulants could potentially reduce the risk of such events, but any benefits could be offset by an increased risk of fatal or disabling haemorrhages.

OBJECTIVES

To assess the effect of prolonged anticoagulant therapy compared with placebo or open control following presumed non-cardioembolic ischaemic stroke or transient ischaemic attack.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register in May 2008. In June 2008 we searched three online trial registers, used Web of Science Cited Reference Search to identify new citations of previously included studies, contacted a pharmaceutical company, and also contacted authors for additional information on included trials.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing at least one month of anticoagulant therapy with control in people with previous, presumed non-cardioembolic, ischaemic stroke or transient ischaemic attack.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality and extracted the data.

MAIN RESULTS

Eleven trials involving 2487 participants were included. The quality of the nine trials which predated routine computerised tomography (CT) scanning and the use of the International Normalised Ratio to monitor anticoagulation was poor. There was no evidence of an effect of anticoagulant therapy on either the odds of death or dependency (two trials, odds ratio (OR) 0.83, 95% confidence interval (CI) 0.52 to 1.34) or of 'non-fatal stroke, myocardial infarction, or vascular death' (four trials, OR 0.96, 95% CI 0.68 to 1.37). Death from any cause (OR 0.95, 95% CI 0.73 to 1.24) and death from vascular causes (OR 0.86, 95% CI 0.66 to 1.13) were not significantly different between treatment and control. The inclusion of two recently completed trials did not alter these conclusions. There was no evidence of an effect of anticoagulant therapy on the risk of recurrent ischaemic stroke (OR 0.85, 95% CI 0.66 to 1.09). However, anticoagulants increased fatal intracranial haemorrhage (OR 2.54, 95% CI 1.19 to 5.45), and major extracranial haemorrhage (OR 3.43, 95% CI 1.94 to 6.08). This is equivalent to anticoagulant therapy causing about 11 additional fatal intracranial haemorrhages and 25 additional major extracranial haemorrhages per year for every 1000 patients given anticoagulant therapy.

AUTHORS' CONCLUSIONS

Compared with control, there was no evidence of benefit from long-term anticoagulant therapy in people with presumed non-cardioembolic ischaemic stroke or transient ischaemic attack, but there was a significant bleeding risk.