External Validation of Risk Scores for Major Bleeding in a Population-Based Cohort of Transient Ischemic Attack and Ischemic Stroke Patients

Bleeding with intensive versus guideline antiplatelet therapy in acute cerebral ischaemia

Intensive antiplatelet therapy did not reduce recurrent stroke/transient ischaemic attack (TIA) events as compared with guideline treatment in the Triple Antiplatelets for Reducing Dependency after Ischaemic Stroke (TARDIS) trial, but did increase the frequency and severity of bleeding. In this pre-specified analysis, we investigated predictors of bleeding and the association of bleeding with outcome. TARDIS was an international prospective randomised open-label blinded-endpoint trial in participants with ischaemic stroke or TIA within 48 h of onset. Participants were randomised to 30 days of intensive antiplatelet therapy (aspirin, clopidogrel, dipyridamole) or guideline-based therapy (either clopidogrel alone or combined aspirin and dipyridamole). Bleeding was defined using the International Society on Thrombosis and Haemostasis five-level ordered categorical scale: fatal, major, moderate, minor, none. Of 3,096 participants, bleeding severity was: fatal 0.4%, major 1.5%, moderate 1.2%, minor 11.4%, none 85.5%. Major/fatal bleeding was increased with intensive as compared with guideline therapy: 39 vs. 17 participants, adjusted hazard ratio 2.21, 95% CI 1.24-3.93, p = 0.007. Bleeding events diverged between treatment groups in the 8-35 day period but not in the 0-7 or 36-90 day epochs. In multivariate analysis more, and more severe, bleeding events were seen with increasing age, female sex, pre-morbid dependency, increased time to randomisation, prior major bleed, prior antiplatelet therapy and in those randomised to triple vs guideline antiplatelet therapy. More severe bleeding was associated with worse clinical outcomes across multiple physical, emotional and quality of life domains.Trial registration ISRCTN47823388 .

Impact of Cerebral Microbleeds in Stroke Patients with Atrial Fibrillation

OBJECTIVES

Cerebral microbleeds are associated with the risks of ischemic stroke and intracranial hemorrhage, causing clinical dilemmas for antithrombotic treatment decisions. We aimed to evaluate the risks of intracranial hemorrhage and ischemic stroke associated with microbleeds in patients with atrial fibrillation treated with vitamin K antagonists, direct oral anticoagulants, antiplatelets, and combination therapy (i.e. concurrent oral anticoagulant and antiplatelet).

METHODS

We included patients with documented atrial fibrillation from the pooled individual patient data analysis by the Microbleeds International Collaborative Network. Risks of subsequent intracranial hemorrhage and ischemic stroke were compared between patients with and without microbleeds, stratified by antithrombotic use.

RESULTS

A total of 7,839 patients were included. The presence of microbleeds was associated with an increased relative risk of intracranial hemorrhage (adjusted hazard ratio [aHR] = 2.74, 95% confidence interval = 1.76-4.26) and ischemic stroke (aHR = 1.29, 95% confidence interval = 1.04-1.59). For the entire cohort, the absolute incidence of ischemic stroke was higher than intracranial hemorrhage regardless of microbleed burden. However, for the subgroup of patients taking combination of anticoagulant and antiplatelet therapy, the absolute risk of intracranial hemorrhage exceeded that of ischemic stroke in those with 2 to 4 microbleeds (25 vs 12 per 1,000 patient-years) and ≥ 11 microbleeds (94 vs 48 per 1,000 patient-years).

INTERPRETATION

Patients with atrial fibrillation and high burden of microbleeds receiving combination therapy have a tendency of higher rate of intracranial hemorrhage than ischemic stroke, with potential for net harm. Further studies are needed to help optimize stroke preventive strategies in this high-risk group. ANN NEUROL 2023;94:61-74.

Role of cerebral microbleeds in acute ischemic stroke and atrial fibrillation

Cerebral microbleeds (CMBs) are commonly detected in the brains of patients with acute ischemic stroke (AIS). With the development of neuroimaging, clinicians are paying more attention to the presence of CMBs. CMBs were found to significantly increase the risk of intracranial hemorrhagic transformation and hemorrhage in patients with AIS, especially in patients with concurrent atrial fibrillation (AF). Additionally, the presence of CMBs is thought to be a symbol of a high risk of recurrent ischemic stroke (IS). A few researchers have found that the presence of CMBs has no significant effect on the prognosis of patients with AIS. Therefore, the current views on the role of CMBs in the prognoses of patients with IS are controversial. The use of anticoagulants and other drugs has also become a dilemma due to the special influence of CMBs on the prognosis of these patients. Due to the large number of patients with AF and CMBs, many studies have been conducted on the effects of CMBs on these patients and subsequent pharmacological treatments. However, at present, there are no relevant guidelines to guide the secondary preventive treatment of patients with stroke, CMBs, and AF. In this paper, we summarized the role of CMBs in AIS combined with AF and relevant preventive measures against the recurrence of stroke and the occurrence of intracerebral hemorrhage to help clarify the specifics of drug therapies for this group of patients.

Anticoagulation after stroke: persistent uncertainties

PURPOSE OF REVIEW

Direct oral anticoagulants (DOAC) are the mainstay of anticoagulant therapy for stroke prevention in patients with nonvalvular atrial fibrillation. Persistent uncertainties remain in different areas, and this review discusses current dilemmas based on selected studies.

RECENT FINDINGS

Optimal timing of DOAC initiation after a recent ischaemic stroke in patients with atrial fibrillation is currently unknown and subject of ongoing randomized controlled trials. Ischaemic stroke despite anticoagulant therapy in patients with atrial fibrillation is frequent, constitutes heterogeneous causes (competing stroke cause, medication error and cardioembolism despite anticoagulation) and optimal treatment is currently unknown. Thorough etiological work-up is justified. Recent randomized controlled trials found no beneficial effect of DOAC therapy in unselected patients with embolic stroke of undetermined source (ESUS). Currently ongoing trials targeting subgroup of ESUS patients with additional atrial cardiopathy will provide novel data. Cerebral mircobleeds combined in a novel risk score (MICON score) provide good predictive value to stratify the risk of intracranial haemorrhage in patients taking anticoagulants. Use of DOAC after intracerebral haemorrhage in patients with atrial fibrillation is subject of ongoing trials.

SUMMARY

There are still significant uncertainties in anticoagulant management in patients with stroke. Ongoing trials will soon provide novel data to improve management of these patients.

Intracranial Hemorrhage During Dual Antiplatelet Therapy: JACC Review Topic of the Week

Dual antiplatelet therapy (DAPT) with acetylsalicylic acid and a P2Y₁₂ inhibitor is an established therapy for a broad spectrum of patients with cardiovascular disease. The ischemic benefit of DAPT is partially offset by its increased bleeding risk, with intracranial hemorrhage (ICH) being the most serious complication. Although uncommon (0.2%-0.3% annually), its cumulative burden can be substantial given the number of patients afflicted by cardiovascular disease worldwide. Patients with a history of stroke or transient ischemic attack harbor a particularly high risk for ICH when treated with DAPT. Prediction rules may assist clinicians when weighing the risk/benefit ratio of prescribing DAPT for patients with stroke/transient ischemic attack in the nonacute, ambulatory setting. Currently, there are no reversal agents that can rapidly and effectively reverse the effect of P2Y₁₂ inhibitors in routine practice, although a reversal agent for ticagrelor is under clinical investigation.

Balancing Benefits and Risks of Long-Term Antiplatelet Therapy in Noncardioembolic Transient Ischemic Attack or Stroke

BACKGROUND AND PURPOSE

Lifelong treatment with antiplatelet drugs is recommended following a transient ischemic attack or ischemic stroke. Bleeding complications may offset the benefit of antiplatelet drugs in patients at increased risk of bleeding and low risk of recurrent ischemic events. We aimed to investigate the net benefit of antiplatelet treatment according to an individuals' bleeding risk.

METHODS

We pooled individual patient data from 6 randomized clinical trials (CAPRIE [Clopidogrel Versus Aspirin in Patients at Risk of Ischemic Events], ESPS-2 [European Stroke Prevention Study-2], MATCH [Management of Atherothrombosis With Clopidogrel in High-Risk Patients], CHARISMA [Clopidogrel for High Atherothrombotic Risk and Ischemic Stabilization, Management, and Avoidance], ESPRIT [European/Australasian Stroke Prevention in Reversible Ischemia Trial], and PRoFESS [Prevention Regimen for Effectively Avoiding Second Strokes]) investigating antiplatelet therapy in the subacute or chronic phase after noncardioembolic transient ischemic attack or stroke. Patients were stratified into quintiles according to their predicted risk of major bleeding with the S₂TOP-BLEED score. The annual risk of major bleeding and recurrent ischemic events was assessed per quintile for 4 scenarios: (1) aspirin monotherapy, (2) aspirin-clopidogrel versus aspirin or clopidogrel monotherapy, (3) aspirin-dipyridamole versus clopidogrel, and (4) aspirin versus clopidogrel. Net benefit was calculated for the second, third, and fourth scenario.

RESULTS

Thirty seven thousand eighty-seven patients were included in the analyses. Both risk of major bleeding and recurrent ischemic events increased over quintiles of predicted bleeding risk, but risk of ischemic events was consistently higher (eg, from 0.7%/y (bottom quintile) to 3.2%/y (top quintile) for major bleeding on aspirin and from 2.5%/y to 10.2%/y for risk of ischemic events on aspirin). Treatment with aspirin-clopidogrel led to more major bleedings (0.9%-1.7% per year), than reduction in ischemic events (ranging from 0.4% to 0.9/1.0% per year) across all quintiles. There was no clear preference for either aspirin-dipyridamole or clopidogrel according to baseline bleeding risk.

CONCLUSIONS

Among patients with a transient ischemic attack or ischemic stroke included in clinical trials of antiplatelet therapy, the risk of recurrent ischemic events and of major bleeding increase in parallel. Antiplatelet treatment cannot be individualized solely based on bleeding risk assessment.

Development of imaging-based risk scores for prediction of intracranial haemorrhage and ischaemic stroke in patients taking antithrombotic therapy after ischaemic stroke or transient ischaemic attack: a pooled analysis of individual patient data from cohort studies

BACKGROUND

Balancing the risks of recurrent ischaemic stroke and intracranial haemorrhage is important for patients treated with antithrombotic therapy after ischaemic stroke or transient ischaemic attack. However, existing predictive models offer insufficient performance, particularly for assessing the risk of intracranial haemorrhage. We aimed to develop new risk scores incorporating clinical variables and cerebral microbleeds, an MRI biomarker of intracranial haemorrhage and ischaemic stroke risk.

METHODS

We did a pooled analysis of individual-patient data from the Microbleeds International Collaborative Network (MICON), which includes 38 hospital-based prospective cohort studies from 18 countries. All studies recruited participants with previous ischaemic stroke or transient ischaemic attack, acquired baseline MRI allowing quantification of cerebral microbleeds, and followed-up participants for ischaemic stroke and intracranial haemorrhage. Participants not taking antithrombotic drugs were excluded. We developed Cox regression models to predict the 5-year risks of intracranial haemorrhage and ischaemic stroke, selecting candidate predictors on biological relevance and simplifying models using backward elimination. We derived integer risk scores for clinical use. We assessed model performance in internal validation, adjusted for optimism using bootstrapping. The study is registered on PROSPERO, CRD42016036602.

FINDINGS

The included studies recruited participants between Aug 28, 2001, and Feb 4, 2018. 15 766 participants had follow-up for intracranial haemorrhage, and 15 784 for ischaemic stroke. Over a median follow-up of 2 years, 184 intracranial haemorrhages and 1048 ischaemic strokes were reported. The risk models we developed included cerebral microbleed burden and simple clinical variables. Optimism-adjusted c indices were 0·73 (95% CI 0·69-0·77) with a calibration slope of 0·94 (0·81-1·06) for the intracranial haemorrhage model and 0·63 (0·62-0·65) with a calibration slope of 0·97 (0·87-1·07) for the ischaemic stroke model. There was good agreement between predicted and observed risk for both models.

INTERPRETATION

The MICON risk scores, incorporating clinical variables and cerebral microbleeds, offer predictive value for the long-term risks of intracranial haemorrhage and ischaemic stroke in patients prescribed antithrombotic therapy for secondary stroke prevention; external validation is warranted.

FUNDING

British Heart Foundation and Stroke Association.

In-hospital prognosis of first-ever noncardiogenic ischemic stroke in patients with and without indication for prestroke antiplatelet therapy: Chinese Stroke Center Alliance

Background

It is unknown about the influence of prestroke antiplatelet use on early outcomes in patients with and without the indication. We aimed to evaluate the in-hospital prognosis of first-ever noncardiogenic ischemic stroke patients with and without indications of antiplatelet use for primary prevention.

Methods

This was a retrospective, observational study based on a prospective hospital-based registry (Chinese Stroke Center Alliance). Using the data with 436,660 first-ever noncardiogenic acute ischemic strokes recorded from Aug 1, 2015, to July 31, 2019, from 1,453 hospitals in China, we examined the associations between the indication for prestroke antiplatelet use and in-hospital clinical outcomes.

Results

Among 436,660 first-ever noncardiogenic ischemic stroke patients, 42,409 patients (9.7%) had a documented previous vascular indication and 394,251 (90.3%) did not. Compared to those without, patients with the indication were associated with increased prevalence of in-hospital morbid conditions, including stroke severity (OR 2.71; 95% CI: 2.62–2.81; P<0.0001), length of stay >14 days (OR 1.16; 95% CI: 1.13–1.19; P<0.0001), mortality (OR 2.20; 95% CI: 1.96–2.46, P<0.0001), and recurrence of ischemic stroke and transient ischemic attack (TIA) (OR 1.5; 95% CI: 1.43–1.59, P<0.0001). Among patients without indication, prestroke antiplatelet use was associated with lower mortality (OR 0.73, 95% CI: 0.56–0.96; P=0.0221); while among patients with indication, those receiving prestroke antiplatelet had lower odds ratios in stroke severity (P<0.0001) and disability (P=0.0003) than those who not.

Conclusions

Patients with indications of prestroke antiplatelet use were more likely to have unfavorable outcomes than those without. Prestroke antiplatelet might be associated with lower mortality, less disability, and less stroke severity in certain population groups. Future studies to improve risk prediction rules are needed to guide effective primary prevention for ischemic stroke.

Bleeding risk assessment for stroke patients on antithrombotic therapy

INTRODUCTION

After an ischemic cerebrovascular event the risk of new ischemic events is high, therefore antithrombotic therapy are indicated to prevent stroke recurrence.

DISCUSSION

Despite its clear benefit, these therapies increase the risk of bleeding. Therefore, it is essential to identify high hemorrhagic risk patients. There are different predictive models of hemorrhage, in particular of intracranial hemorrhage, associated with the use of antiaggregants in patients who have presented an ischemic stroke or TIA, such as the CCSC, intracranial scales -B2LEED3S score or S2TOP-BLEED. However, though main international guidelines recommend the use of scales, in particular, the HAS-BLED score, to assess the risk of bleeding in anticoagulated patients, there is no specific recommendation in the case of the use of antiplatelet drugs.

CONCLUSIONS

In this review we present the main models currently available for the prediction of bleeding of antithrombotic therapy in patients who have had a stroke or TIA.

Targeting von Willebrand Factor in Ischaemic Stroke: Focus on Clinical Evidence

Despite great efforts in stroke research, disability and recurrence rates in ischaemic stroke remain unacceptably high. To address this issue, one potential target for novel therapeutics is the glycoprotein von Willebrand factor (vWF), which increases in thrombogenicity especially under high shear rates as it bridges between vascular sub-endothelial collagen and platelets. The rationale for vWF as a potential target in stroke comes from four bodies of evidence. (1) Animal models which recapitulate the pathogenesis of stroke and validate the concept of targeting vWF for stroke prevention and the use of the vWF cleavage enzyme ADAMTS13 in acute stroke treatment. (2) Extensive epidemiologic data establishing the prognostic role of vWF in the clinical setting showing that high vWF levels are associated with an increased risk of first stroke, stroke recurrence or stroke-associated mortality. As such, vWF levels may be a suitable marker for further risk stratification to potentially fine-tune current risk prediction models which are mainly based on clinical and imaging data. (3) Genetic studies showing an association between vWF levels and stroke risk on genomic levels. Finally, (4) studies of patients with primary disorders of excess or deficiency of function in the vWF axis (e.g. thrombotic thrombocytopenic purpura and von Willebrand disease, respectively) which demonstrate the crucial role of vWF in atherothrombosis. Therapeutic inhibition of VWF by novel agents appears particularly promising for secondary prevention of stroke recurrence in specific sub-groups of patients such as those suffering from large artery atherosclerosis, as designated according to the TOAST classification.