Colchicine in High-risk Patients with Acute Minor-to-moderate Ischemic Stroke or Transient Ischemic Attack (CHANCE-3): Rationale and design of a multicenter randomized placebo-controlled trial

BACKGROUND

Anti-inflammatory therapy using colchicine has reduced recurrent vascular events in patients with coronary heart disease.

DESIGN

Colchicine in High-risk Patients with Acute Minor-to-moderate Ischemic Stroke or Transient Ischemic Attack (CHANCE-3) is a randomized, double-blind, placebo-controlled multicenter trial, in which 8,238 patients with acute minor-to-moderate ischemic stroke (NIHSS≤5) or high-risk TIA (ABCD2 score ≥ 4) and a hsCRP level of ≥2mg/L will be randomly assigned within 24 hours of symptom onset to colchicine (1 mg daily on days 1-3, followed by 0.5 mg daily for a total of 90 days) or matching placebo, on a background of optimal medical therapy. The study will have 90% power to detect a 25% reduction in the primary efficacy outcome of any stroke within 3 months of randomization. Adverse events potentially related to the use of colchicine will also be analyzed. The primary analysis will be by intention-to-treat.

DISCUSSION

The CHANCE-3 trial will evaluate the efficacy and safety of colchicine for secondary prevention after stroke and TIA.Trial registry name: Colchicine in High-risk Patients With Acute MiNor-to-moderate IschemiC Stroke or TransiEnt Ischemic Attack (CHANCE-3); URL: https://clinicaltrials.gov/ct2/show/NCT05439356?cond=CHANCE-3&draw=2&rank=1; Registration number: NCT05439356.

Subsequent ischemic stroke and tobacco smoking: A secondary analysis of the POINT trial

Background:

The aim of this study was to determine the effect of smoking status on subsequent stroke risk in patients with minor ischemic stroke or TIA and to determine whether smoking modifies the effect of clopidogrel-based DAPT on subsequent stroke risk.

Methods:

This was a post-hoc analysis of the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial, which had a 90-day follow-up period. We used multivariable Cox regression and subgroup interaction analysis to determine the effect of smoking on the risk of subsequent ischemic stroke and major hemorrhage, respectively.

Results:

Data from 4877 participants enrolled in the POINT trial were analyzed. Among these, 1004 were current smokers and 3873 were non-smokers at the time of index event. Smoking was associated with a non-significant trend toward an increased risk of subsequent ischemic stroke during follow up (adjusted HR, 1.31 (95% CI, 0.97–1.78), p = 0.076). The effect of clopidogrel on ischemic stroke did not differ between non-smokers (HR, 0.74 (95% CI, 0.56–0.98), p = 0.03) and smokers (HR, 0.63 (95% CI, 0.37–1.05), p = 0.078), p for interaction = 0.572. Similarly, the effect of clopidogrel on major hemorrhage did not differ between non-smokers (hazard ratio, 1.67 (95% CI, 0.40–7.00), p = 0.481) and smokers (HR, 2.59 (95% CI, 1.08–6.21), p = 0.032), p for interaction = 0.613.

Conclusions:

In this post-hoc analysis of the POINT trial we found that the effect of clopidogrel on reducing subsequent ischemic stroke as well as risk of major hemorrhage did not depend on smoking status, indicating that smokers benefit to a similar degree from DAPT as non-smokers.

Predictors of Recurrent Stroke After Embolic Stroke of Undetermined Source in the RE-SPECT ESUS Trial

Background

We sought to determine recurrent stroke predictors among patients with embolic strokes of undetermined source (ESUS).

Methods and Results

We applied Cox proportional hazards models to identify clinical features associated with recurrent stroke among participants enrolled in RE‐SPECT ESUS (Randomized, Double‐Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) trial, an international clinical trial evaluating dabigatran versus aspirin for patients with ESUS. During a median follow‐up of 19 months, 384 of 5390 participants had recurrent stroke (annual rate, 4.5%). Multivariable models revealed that stroke or transient ischemic attack before the index event (hazard ratio [HR], 2.27 [95% CI, 1.83–2.82]), creatinine clearance <50 mL/min (HR, 1.69 [95% CI, 1.23–2.32]), male sex (HR, 1.60 [95% CI, 1.27–2.02]), and CHA₂DS₂‐VASc ≥4 (HR, 1.55 [95% CI, 1.15–2.08] and HR, 1.66 [95% CI, 1.21–2.26] for scores of 4 and ≥5, respectively) versus CHA₂DS₂‐VASc of 2 to 3, were independent predictors for recurrent stroke.

Conclusions

In RE‐SPECT ESUS trial, expected risk factors previously linked to other common stroke causes were associated with stroke recurrence. These data help define high‐risk groups for subsequent stroke that may be useful for clinicians and for researchers designing trials among patients with ESUS.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120.

Review and update of the concept of embolic stroke of undetermined source

Ischaemic strokes have traditionally been classified according to the TOAST criteria, in which strokes with unclear aetiology are classified as cryptogenic strokes. However, the definition of cryptogenic stroke did not meet the operational criteria necessary to define patient populations for randomized treatment trials. To address this problem, the concept of embolic stroke of undetermined source (ESUS) was developed and published in 2014. A hypothesis that underpinned this concept was that most strokes in patients with ESUS are caused by embolic events, perhaps many cardioembolic, and that anticoagulation would prevent secondary ischaemic events. On this basis, two large randomized trials were conducted to compare the non-vitamin K antagonist oral anticoagulants (NOACs) dabigatran and rivaroxaban with aspirin. Neither NOAC was superior to aspirin in these trials, although subgroups of patients with ESUS seemed to benefit specifically from anticoagulation or antiplatelet therapy. The neutral results of the trials of anticoagulation and insights into ESUS from research conducted since the concept was introduced warrant reassessment of the ESUS construct as a research concept and a treatment target. In this Review, we discuss the evidence produced since the concept of ESUS was introduced, and propose updates to the criteria and diagnostic algorithm in light of the latest knowledge.

Abstract 159: Recurrent Ischemic Stroke And Cigarette Smoking: A Secondary Analysis Of The POINT Trial

Background: Recent data suggest that in patients with acute myocardial infarction (MI), the effect of clopidogrel on risk reduction of cardiovascular outcomes is more pronounced in smokers. The aim of this study was to determine the effect of smoking status on subsequent stroke risk in patients with minor ischemic stroke or TIA and determine whether smoking improves the effect of clopidogrel treatment on subsequent stroke risk reduction.

Methods: This was a post-hoc analysis of the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial. The POINT trial compared clopidogrel plus aspirin (DAPT) to aspirin alone for prevention of recurrent stroke, myocardial infarction, or vascular death within 3 months of a high-risk TIA or minor ischemic stroke. We used multivariable cox-regression models to determine the effect of smoking on the risk of subsequent ischemic stroke. We also performed interaction analyses to determine whether the effect of clopidogrel on subsequent ischemic stroke differed with respect to smoking status.

Results: Data from 4,877 participants enrolled in the POINT trial were analyzed. Among these, 1,004 were current smokers and 3,873 were non-smokers. Smoking was associated with a non-significantly increased risk of recurrent ischemic stroke during follow up (hazard ratio, 1.31 [95% CI, 0.97 - 1.78], P=0.076). The effect of clopidogrel on ischemic stroke was not significantly different in non-smokers (hazard ratio, 0.74 [95% CI, 0.56 - 0.98], P=0.03) compared to smokers (adjusted hazard ratio, 0.63 [95% CI, 0.37 - 1.05], P=0.078), P for interaction = 0.572. In addition, the effect of clopidogrel on major hemorrhage was not significantly different in current smokers (hazard ratio, 2.59 [95% CI, 1.08 - 6.21], P=0.032) compared to non-smokers (hazard ratio, 1.67 [95% CI, 0.40 - 7.00], P=0.481), P for interaction = 0.613.

Conclusions: Cigarette smoking was associated with a non-significantly higher risk of subsequent ischemic stroke and smoking did not modify the effect of clopidogrel-based dual antiplatelet therapy on subsequent ischemic stroke risk reduction. Every effort should be made to encourage tobacco dependence treatment and cessation in patients with minor ischemic stroke and TIA.

Infarct on Brain Imaging, Subsequent Ischemic Stroke, and Clopidogrel-Aspirin Efficacy: A Post Hoc Analysis of a Randomized Clinical Trial

IMPORTANCE

In the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial, acute treatment with clopidogrel-aspirin was associated with significantly reduced risk of recurrent stroke. There may be specific patient groups who are more likely to benefit from this treatment.

OBJECTIVE

To investigate whether the association of clopidogrel-aspirin with stroke recurrence in patients with minor stroke or high-risk transient ischemic attack (TIA) is modified by the presence of infarct on imaging attributed to the index event (index imaging) among patients enrolled in the POINT Trial.

DESIGN, SETTING, AND PARTICIPANTS

In the POINT randomized clinical trial, patients with high-risk TIA and minor ischemic stroke were enrolled at 269 sites in 10 countries in North America, Europe, Australia, and New Zealand from May 28, 2010, to December 19, 2017. In this post hoc analysis, patients were divided into 2 groups according to whether they had an acute infarct on index imaging. All POINT trial participants with information available on the presence or absence of acute infarct on index imaging were eligible for this study. Univariable Cox regression models evaluated associations between the presence of an infarct on index imaging and subsequent ischemic stroke and evaluated whether the presence of infarct on index imaging modified the association of clopidogrel-aspirin with subsequent ischemic stroke risk. Data were analyzed from July 2020 to May 2021.

EXPOSURES

Presence or absence of acute infarct on index imaging.

MAIN OUTCOMES AND MEASURES

The primary outcome is whether the presence of infarct on index imaging modified the association of clopidogrel-aspirin with subsequent ischemic stroke risk.

RESULTS

Of the 4881 patients enrolled in POINT, 4876 (99.9%) met the inclusion criteria (mean [SD] age, 65 [13] years; 2685 men [55.0%]). A total of 1793 patients (36.8%) had an acute infarct on index imaging. Infarct on index imaging was associated with ischemic stroke during follow-up (hazard ratio [HR], 3.68; 95% CI, 2.73-4.95; P < .001). Clopidogrel-aspirin vs aspirin alone was associated with decreased ischemic stroke risk in patients with an infarct on index imaging (HR, 0.56; 95% CI, 0.41-0.77; P < .001) compared with those without an infarct on index imaging (HR, 1.11; 95% CI, 0.74-1.65; P = .62), with a significant interaction association (P for interaction = .008).

CONCLUSIONS AND RELEVANCE

In this study, the presence of an acute infarct on index imaging was associated with increased risk of recurrent stroke and a more pronounced benefit from clopidogrel-aspirin. Future work should focus on validating these findings before targeting specific patient populations for acute clopidogrel-aspirin treatment.

Antiplatelet Use and Ischemic Stroke Risk in Minor Stroke or Transient Ischemic Attack: A Post Hoc Analysis of the POINT Trial

BACKGROUND AND PURPOSE

Dual antiplatelet therapy has been shown to reduce the risk of recurrent stroke in patients with minor stroke or transient ischemic attack. However, whether the effect of dual antiplatelet therapy is modified by pretreatment antiplatelet status is unclear.

METHODS

This is a post hoc analysis of the POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke). Patients were divided into 2 groups based on pretreatment antiplatelet use. The primary outcome was ischemic stroke within 90 days of randomization.

RESULTS

We included 4881 patients of whom 41% belonged to the no pretreatment antiplatelet. Ischemic stroke occurred in 6% and 5% in the antiplatelet pretreatment and no antiplatelet pretreatment, respectively. Antiplatelet pretreatment was not associated with the risk of ischemic stroke (adjusted hazard ratio, 1.05 [95% CI, 0.81-137]) or risk of major hemorrhage (hazard ratio, 1.10 [95% CI, 0.55-2.21]; P=0.794). The effect of dual antiplatelet therapy on recurrent ischemic stroke risk was not different in patients who were on antiplatelet before randomization (adjusted hazard ratio, 0.69 [95% CI, 0.50-0.94]) as opposed to those who were not (adjusted hazard ratio, 0.75 [95% CI, 0.50-1.12]), P for interaction = 0.685.

CONCLUSIONS

In patients with minor stroke and high-risk transient ischemic attack, dual antiplatelet therapy reduces the risk of ischemic stroke regardless of premorbid antiplatelet use.

Predictors of Atrial Fibrillation Development in Patients With Embolic Stroke of Undetermined Source: An Analysis of the RE-SPECT ESUS Trial

BACKGROUND

A proportion of patients with embolic stroke of undetermined source have silent atrial fibrillation (AF) or develop AF after the initial evaluation. Better understanding of the risk for development of AF is critical to implement optimal monitoring strategies with the goal of preventing recurrent stroke attributable to underlying AF. The RE-SPECT ESUS trial (Randomized, Double-Blind Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) provides an opportunity to assess predictors for developing AF and associated recurrent stroke.

METHODS

RE-SPECT ESUS was a randomized, controlled trial (564 sites, 42 countries) assessing dabigatran versus aspirin for the prevention of recurrent stroke in patients with embolic stroke of undetermined source. Of 5390 patients enrolled and followed for a median of 19 months, 403 (7.5%) were found to develop AF reported as an adverse event or using cardiac monitoring per standard clinical care. Univariable and multivariable regression analyses were performed to define predictors of AF.

RESULTS

In the multivariable model, older age (odds ratio for 10-year increase, 1.99 [95% CI, 1.78-2.23]; P<0.001), hypertension (odds ratio, 1.36 [95% CI, 1.03-1.79]; P=0.0304), diabetes (odds ratio, 0.74 [95% CI, 0.56-0.96]; P=0.022), and body mass index (odds ratio for 5-U increase, 1.29 [95% CI, 1.16-1.43]; P<0.001) were independent predictors of AF during the study. In a sensitivity analysis restricted to 1117 patients with baseline NT-proBNP (N-terminal prohormone of brain natriuretic peptide) measurements, only older age and higher NT-proBNP were significant independent predictors of AF. Performance of several published predictive models was assessed, including HAVOC (AF risk score based on hypertension, age ≥75 years, valvular heart disease, peripheral vascular disease, obesity, congestive heart failure, and coronary artery disease) and CHA₂DS₂-VASc (stroke risk score based on congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, previous stroke, transient ischemic attack or thromboembolism [doubled], vascular disease, age 65 to 74 years, and sex category [female]) scores, and higher scores were associated with higher rates of developing AF.

CONCLUSIONS

Besides age, the most important variable, several other factors, including hypertension, higher body mass index, and lack of diabetes, are independent predictors of AF after embolic stroke of undetermined source. When baseline NT-proBNP was available, only older age and elevation of this biomarker were predictive of subsequent AF. Understanding who is at higher risk of developing AF will assist in identifying patients who may benefit from more intense, long-term cardiac monitoring. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120.

Outcomes Associated With Clopidogrel-Aspirin Use in Minor Stroke or Transient Ischemic Attack: A Pooled Analysis of Clopidogrel in High-Risk Patients With Acute Non-Disabling Cerebrovascular Events (CHANCE) and Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trials

Importance

Dual antiplatelet therapy with clopidogrel and aspirin is effective for secondary prevention after minor ischemic stroke or transient ischemic attack (TIA). Uncertainties remained about the optimal duration of dual antiplatelet therapy for minor stroke or TIA.

Objective

To obtain precise estimates of efficacy and risk of dual antiplatelet therapy after minor ischemic stroke or TIA.

Design, Setting, and Participants

This analysis pooled individual patient-level data from 2 large-scale randomized clinical trials that evaluated clopidogrel-aspirin as a treatment to prevent stroke after a minor stroke or high-risk TIA. The Clopidogrel in High-Risk Patients With Acute Non-Disabling Cerebrovascular Events (CHANCE) trial enrolled patients at 114 sites in China from October 1, 2009, to July 30, 2012. The Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial enrolled patients at 269 international sites from May 28, 2010, to December 19, 2017. Both were followed up for 90 days. Data analysis occurred from November 2018 to May 2019.

Interventions

In the 2 trials, patients with minor stroke or high-risk TIA were randomized to clopidogrel-aspirin or aspirin alone within 12 hours (POINT) or 24 hours (CHANCE) of symptom onset.

Main Outcomes and Measures

The primary efficacy outcome was a major ischemic event (ischemic stroke, myocardial infarction, or death from ischemic vascular causes). The primary safety outcome was major hemorrhage.

Results

The study enrolled 5170 patients (CHANCE) and 4881 patients (POINT). Analysis included individual data from 10 051 patients (5016 in the clopidogrel-aspirin treatment group and 5035 in the control group) with a median age of 63.2 (interquartile range, 55.0-72.9) years; 6106 patients (60.8%) were male. Clopidogrel-aspirin treatment reduced the risk of major ischemic events at 90 days compared with aspirin alone (328 of 5016 [6.5%] vs 458 of 5035 [9.1%]; hazard ratio [HR], 0.70 [95% CI, 0.61-0.81]; P < .001), mainly within the first 21 days (263 of 5016 [5.2%] vs 391 of 5035 [7.8%]; HR, 0.66 [95% CI, 0.56-0.77]; P < .001), but not from day 22 to day 90. No evidence of heterogeneity of treatment outcome across trials or prespecified subgroups was observed. Major hemorrhages were more frequent in the clopidogrel-aspirin group, but the difference was nonsignificant.

Conclusions and Relevance

In this analysis of the POINT and CHANCE trials, the benefit of dual antiplatelet therapy appeared to be confined to the first 21 days after minor ischemic stroke or high-risk TIA.

Evaluation of Systolic Blood Pressure, Use of Aspirin and Clopidogrel, and Stroke Recurrence in the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke Trial

IMPORTANCE

Elevated systolic blood pressure (SBP) after acute ischemic stroke and transient ischemic attack (TIA) is associated with future stroke risk.

OBJECTIVE

To explore the association of dual antiplatelet therapy (DAPT) with stroke recurrence among patients with acute ischemic stroke and TIA with or without elevated baseline SBP.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study performed a post hoc subgroup analysis of the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial, which was a multicenter trial conducted from 2010 to 2018 at 269 sites in 10 countries in North America, Europe, Australia, and New Zealand. Patients enrolled in POINT with available blood pressure and outcome data were included in this cohort. Statistical analysis was performed from November 2020 to January 2021.

EXPOSURES

Baseline SBP less than 140 mm Hg vs greater than or equal to 140 mm Hg and the interaction term of SBP (<140 mm Hg vs ≥140 mm Hg) × treatment group (aspirin vs DAPT).

MAIN OUTCOMES AND MEASURES

The primary outcome was ischemic stroke during 90 days of follow-up. The statistical analysis fit Cox proportional hazards models adjusted for patient age, race, premorbid hypertension, diabetes, and final diagnosis of the qualifying event (stroke vs TIA).

RESULTS

Among 4781 patients in the cohort, the mean (SD) age was 64.6 (13.1) years; 2142 (44.8%) were male individuals, 3487 (72.9%) were White individuals, and 266 (5.6%) had a primary outcome of ischemic stroke during follow-up. There were 946 patients (19.8%) with baseline SBP less than 140 mm Hg and 3835 (80.2%) with SBP greater than or equal to 140 mm Hg. The interaction term (SBP × treatment) was significant (P for interaction = .03). In the subgroup of patients with SBP less than 140 mm Hg, the hazard ratio (HR) of DAPT vs aspirin alone for ischemic stroke was 0.36 (95% CI, 0.18-0.72; P = .004), whereas the HR in the subgroup with SBP greater than or equal to 140 mm Hg was 0.79 (95% CI, 0.60-1.02; P = .08). When evaluating the outcome of ischemic stroke within 7 days of randomization, the interaction term was significant (P for interaction = .02), and the HR for patients with DAPT with SBP less than 140 mm Hg was 0.19 (95% CI, 0.07-0.55; P = .002).

CONCLUSIONS AND RELEVANCE

In the POINT trial, patients with SBP less than 140 mm Hg at presentation received a greater benefit from 90 days of DAPT than those with higher baseline SBP, particularly for reduction of early ischemic stroke recurrence. Additional research is needed to replicate these findings and potentially test whether mild SBP reduction and DAPT within 12 hours of stroke onset lowers early risk of stroke recurrence.

Carotid Stenosis and Recurrent Ischemic Stroke: A Post-Hoc Analysis of the POINT Trial

BACKGROUND AND PURPOSE

Randomized trials demonstrated the benefit of dual antiplatelet therapy in patients with minor ischemic stroke or high-risk transient ischemic attack. We sought to determine whether the presence of carotid stenosis was associated with increased risk of ischemic stroke and whether the addition of clopidogrel to aspirin was associated with more benefit in patients with versus without carotid stenosis.

METHODS

This is a post-hoc analysis of the POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke) that randomized patients with minor ischemic stroke or high-risk transient ischemic attack within 12 hours from last known normal to receive either clopidogrel plus aspirin or aspirin alone. The primary predictor was the presence of ≥50% stenosis in either cervical internal carotid artery. The primary outcome was ischemic stroke. We built Cox regression models to determine the association between carotid stenosis and ischemic stroke and whether the effect of clopidogrel was modified by ≥50% carotid stenosis.

RESULTS

Among 4881 patients enrolled POINT, 3941 patients met the inclusion criteria. In adjusted models, ≥50% carotid stenosis was associated with ischemic stroke risk (hazard ratio, 2.45 [95% CI, 1.68-3.57], P<0.001). The effect of clopidogrel (versus placebo) on ischemic stroke risk was not significantly different in patients with <50% carotid stenosis (adjusted hazard ratio, 0.68 [95% CI, 0.50-0.93], P=0.014) versus those with ≥50% carotid stenosis (adjusted hazard ratio, 0.88 [95% CI, 0.45-1.72], P=0.703), P value for interaction=0.573.

CONCLUSIONS

The presence of carotid stenosis was associated with increased risk of ischemic stroke during follow-up. The effect of added clopidogrel was not significantly different in patients with versus without carotid stenosis. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03354429.

Newly Diagnosed Atrial Fibrillation After Transient Ischemic Attack Versus Minor Ischemic Stroke in the POINT Trial

Background

Atrial fibrillation/flutter (AF) after transient ischemic attack (TIA) has not been well studied. We compared the likelihood of new AF diagnosis after ischemic stroke versus TIA.

Methods and Results

The POINT (Platelet‐Oriented Inhibition in New TIA and Minor Ischemic Stroke) trial enrolled adults within 12 hours of minor ischemic stroke or high‐risk TIA. Our exposure was index event type (ischemic stroke versus TIA). The primary analysis used the original trial definition of TIA (resolution of symptoms/signs). In secondary analyses, TIA cases with infarction on neuroimaging were reclassified as strokes. Our primary outcome was a new AF diagnosis, ascertained from adverse event and treatment interruption/discontinuation reports. We calculated C‐statistics for variables associated with newly diagnosed AF. We used Kaplan‐Meier survival statistics and Cox models adjusted for demographics and vascular risk factors. Excluding 49 subjects with baseline AF, 2746 patients had index stroke and 2086 patients had index TIA. During the 90‐day follow‐up, 106 patients had newly diagnosed AF. Cumulative risks of AF were 2.7% (95% CI, 2.1%–3.4%) after stroke and 2.0% (95% CI, 1.5%–2.7%) after TIA (P=0.15). After reclassifying index events by neuroimaging, cumulative AF risk was higher after stroke (2.7%; 95% CI, 2.2%–3.4%) than TIA (1.8%; 95% CI, 1.3%–2.5%) (P=0.04). Index event type had negligible predictive utility (C‐statistic, 0.54).

Conclusions

Among patients with cerebral ischemia, the distinction between TIA versus minor stroke did not stratify the risk of subsequent AF diagnosis, implying that patients with TIA should undergo similar heart‐rhythm monitoring strategies as patients with ischemic stroke.

Abstract 59: Presence of Infarct Predicts Recurrence and Efficacy of Dual Antiplatelet Therapy: A Post-Hoc Analysis of the POINT Trial

Background: The combination of aspirin and clopidogrel for 90 days after minor stroke or transient ischemic attack (TIA) reduced the risk of recurrent stroke in the POINT trial. The risk reduction was greater in patients with infarct on CT or MRI compared to those without infarct.

Objective: To investigate the effect of DAPT on minor stroke and TIA in the POINT trial based on (1) the presence or absence of infarct attributed to the index event (“index infarct”) and (2) whether the index event was classified as stroke or TIA.

Design/Methods: Patients were divided into two groups based on whether they had an “index infarct” or not. Baseline demographics and clinical variables were compared between groups using standard statistical tests. We used univariate and multivariable cox-regression models to determine associations between presence of infarct on imaging and primary and secondary outcomes, and interaction analyses to determine whether the presence of “index infarct” modifies the effect of DAPT on study outcomes. We also explored whether the association of “index-infarct” with primary and secondary outcomes varied by index diagnosis (TIA vs. minor stroke).

Results: Amongst 4881 enrolled in POINT, 4876 patients had data on whether there was an “index-infarct”; 1793 (36.8%) had “index-infarct”. In adjusted cox-regression analyses, the presence of “index infarct” was associated with the primary efficacy outcome (HR 3.02 95% CI 2.34-3.89, p < 0.01) and subsequent ischemic stroke (HR 3.10 95% CI 2.39-4.02, p < 0.01). The effect of DAPT vs. aspirin on primary efficacy outcome was more pronounced in patients with “index infarct” (HR 0.58 95% CI 0.43-0.79, p <0.01) vs. those without (HR 1.16 95% CI 0.79-1.71, p=0.44) (p for interaction = 0.01). In a secondary analysis based on final diagnosis, the effect of “index infarct” on primary outcome was only significant in those with minor stroke at the time of randomization (p for interaction=0.01) but not TIA at the time of randomization (p for interaction=0.36).

Conclusions: In the POINT trial, efficacy of DAPT was greater in patients with infarct on imaging attributed to the index event. Future work should focus on determining clinical factors associated with this group to help identify patients most likely to benefit from acute DAPT.

Dabigatran or Aspirin in East Asian Patients With Embolic Stroke of Undetermined Source: RE-SPECT ESUS Subgroup Analysis

BACKGROUND AND PURPOSE

We assessed the outcomes of dabigatran versus aspirin in a prespecified subgroup analysis of East Asian patients with embolic stroke of undetermined source in the RE-SPECT ESUS trial (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source).

METHODS

Patients with a recent embolic stroke of undetermined source were randomized to dabigatran (150 or 110 mg BID) or aspirin (100 mg QD). The primary efficacy outcome was recurrent stroke; the primary safety outcome was major bleeding. The East Asia cohort was compared with patients from all other countries (non-East Asia cohort).

RESULTS

Overall, 988 of 5390 patients (18%) were randomized in East Asia. During a median follow-up of 18.8 months, there was no statistically significant difference in recurrent stroke (hazard ratio, 0.65 [95% CI, 0.41-1.03]) or major bleeding (hazard ratio, 1.04 [95% CI, 0.57-1.91]) in East Asian patients receiving dabigatran versus aspirin. Death from any cause occurred more often in the dabigatran versus the aspirin group (hazard ratio, 3.98 [95% CI, 1.32-12.01]).

CONCLUSIONS

The treatment effect of dabigatran versus aspirin was consistent between cohorts, with no apparent superiority for dabigatran over aspirin in preventing recurrent stroke in patients with embolic stroke of undetermined source. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239120.

Dabigatran or Aspirin After Embolic Stroke of Undetermined Source in Patients With Patent Foramen Ovale: Results From RE-SPECT ESUS

BACKGROUND AND PURPOSE

Patent foramen ovale (PFO) may increase the risk of embolic stroke of undetermined source (ESUS). Guidelines suggest anticoagulation may be more effective than antiplatelets in preventing stroke in patients with ESUS and PFO when interventional closure is not performed.

METHODS

Patients with ESUS randomized to dabigatran (150/110 mg BID) or aspirin (100 mg QD) from the RE-SPECT ESUS study (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) were included. The rate of recurrent stroke (primary end point) and ischemic stroke was reported for patients with and without baseline PFO. A meta-analysis comparing the effects of anticoagulant and antiplatelet therapy on ischemic stroke in patients with PFO was updated to include RE-SPECT ESUS.

RESULTS

PFO was present in 680 of 5388 (12.6%) patients with documented PFO status. The risk of recurrent stroke with dabigatran versus aspirin was similar in patients with and without PFO (P for interaction, 0.8290). In patients with PFO, the meta-analysis found no statistically significant difference between anticoagulant and antiplatelet therapy (odds ratio, 0.70 [95% CI, 0.43-1.14]) for ischemic stroke.

CONCLUSIONS

There is insufficient evidence to recommend anticoagulation over antiplatelet therapy for patients with ESUS and a PFO. More data are needed to guide antithrombotic therapy in this population. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239120.

Non-vitamin K oral anticoagulants for secondary stroke prevention in patients with atrial fibrillation

The aims of this article are to review the evidence regarding the use of non-vitamin K oral anticoagulants (NOACs) for secondary stroke prevention as compared to vitamin K antagonists in patients with atrial fibrillation (AF) and in patients with embolic strokes of uncertain source (ESUS), and when to initiate or resume anticoagulation after an ischaemic stroke or intracranial haemorrhage. Four large trials compared NOACs with warfarin in patients with AF. In our meta-analyses, the rate of all stroke or systemic embolism (SE) was 4.94% with NOACs vs. 5.73% with warfarin. Among the patients with AF and previous transient ischaemic attack or ischaemic stroke, the rate of haemorrhagic stroke was halved with a NOAC vs. warfarin, and the rate of major bleeding was 5.7% with a NOAC vs. 6.4% with warfarin. There was no significant difference in mortality. In a trial comparing apixaban with aspirin in patients with AF, the rate of stroke or SE was 2.4% at 1 year with apixaban vs. 9.2% at 1 year with aspirin and the rates of major bleeding were 4.1% with apixaban vs. 2.9% with aspirin. Data from registries confirmed the results from the randomized trials. Initiation or resumption of anticoagulation after ischaemic stroke or cerebral haemorrhage depends on the size and severity of stroke and the risk of recurrent bleeding. Two large trials tested the hypothesis that NOACs are more effective than 100 mg aspirin in patients with ESUS. Neither trial showed a significant benefit of the NOAC over aspirin. In the meta-analysis, the rate all stroke or SE was 4.94% with NOACs vs. 5.73% with warfarin and the rate of haemorrhagic stroke was halved with a NOAC. The four NOACs had broadly similar efficacy for the major outcomes in secondary stroke prevention.

Methodologies for pragmatic and efficient assessment of benefits and harms: Application to the SOCRATES trial

BACKGROUND/AIMS

Standard approaches to trial design and analyses can be inefficient and non-pragmatic. Failure to consider a range of outcomes impedes evidence-based interpretation and reduces power. Traditional approaches synthesizing information obtained from separate analysis of each outcome fail to incorporate associations between outcomes and recognize the cumulative nature of outcomes in individual patients, suffer from competing risk complexities during interpretation, and since efficacy and safety analyses are often conducted on different populations, generalizability is unclear. Pragmatic and efficient approaches to trial design and analyses are needed.

METHODS

Approaches providing a pragmatic assessment of benefits and harms of interventions, summarizing outcomes experienced by patients, and providing sample size efficiencies are described. Ordinal outcomes recognize finer gradations of patient responses. Desirability of outcome ranking is an ordinal outcome combining benefits and harms within patients. Analysis of desirability of outcome ranking can be based on rank-based methodologies including the desirability of outcome ranking probability, the win ratio, and the proportion in favor of treatment. Partial credit analyses, involving grading the levels of the desirability of outcome ranking outcome similar to an academic test, provides an alternative approach. The methodologies are demonstrated using the acute stroke or transient ischemic attack treated with aspirin or ticagrelor and patient outcomes study (SOCRATES; NCT01994720), a randomized clinical trial.

RESULTS

Two 5-level ordinal outcomes were developed for SOCRATES. The first was based on a modified Rankin scale. The odds ratio is 0.86 (95% confidence interval = 0.75, 0.99; p = 0.04) indicating that the odds of worse stroke categorization for a trial participant assigned to ticagrelor is 0.86 times that of a trial participant assigned to aspirin. The 5-level desirability of outcome ranking outcome incorporated and prioritized survival; the number of strokes, myocardial infarction, and major bleeding events; and whether a stroke event was disabling. The desirability of outcome ranking probability and win ratio are 0.504 (95% confidence interval = 0.499, 0.508; p = 0.10) and 1.11 (95% confidence interval = 0.98, 1.26; p = 0.10), respectively, implying that the probability of a more desirable result with ticagrelor is 50.4% and that a more desirable result occurs 1.11 times more frequently on ticagrelor versus aspirin.

CONCLUSION

Ordinal outcomes can improve efficiency through required pre-specification, careful construction, and analyses. Greater pragmatism can be obtained by composing outcomes within patients. Desirability of outcome ranking provides a global assessment of the benefits and harms that more closely reflect the experience of patients. The desirability of outcome ranking probability, the proportion in favor of treatment, the win ratio, and partial credit can more optimally inform patient treatment, enhance the understanding of the totality of intervention effects on patients, and potentially provide efficiencies over standard analyses. The methods provide the infrastructure for incorporating patient values and estimating personalized effects.

Efficacy of Clopidogrel for Prevention of Stroke Based on CYP2C19 Allele Status in the POINT Trial

Background and Purpose:

Clopidogrel is an antiplatelet drug that is metabolized to its active form by the CYP2C19 enzyme. The CHANCE trial (Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events) found a significant interaction between loss-of-function allele status for the CYP2C19 gene and the effect of dual antiplatelet therapy with aspirin and clopidogrel on the rate of early recurrent stroke following acute transient ischemic attack/minor stroke. The POINT (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke Trial), similar in design to CHANCE but performed largely in North America and Europe, demonstrated a reduction in early recurrent stroke with dual antiplatelet therapy compared with aspirin alone. This substudy was done to evaluate a potential interaction between loss-of-function CYP2C19 alleles and outcome by treatment group in POINT.

Methods:

Of the 269 sites in 10 countries that enrolled patients in POINT, 134 sites participated in this substudy. DNA samples were genotyped for CYP2C19 *2, *3, and *17 alleles and classified as being carriers or noncarriers of loss-of-function alleles. Major ischemia consisted of ischemic stroke, myocardial infarction, or ischemic vascular death.

Results:

Nine hundred thirty-two patients provided analyzable DNA. The rates of major ischemia were 6.7% for the aspirin group versus 2.3% for the dual antiplatelet therapy group (hazard ratio, 0.33 [95% CI, 0.09–1.21]; P =0.09) among carriers of loss-of-function allele. The rates of major ischemia were 5.6% for the aspirin group versus 3.7% for the dual antiplatelet therapy group (hazard ratio, 0.65 [95% CI, 0.32–1.34]; P =0.25) among noncarriers. There was no significant interaction by genotype for major ischemia ( P =0.36) or stroke ( P =0.33).

Conclusions:

This substudy of POINT found no significant interaction with CYP2C19 loss-of-function carrier status and outcome by treatment group. Failure to confirm the findings from the CHANCE trial may be because the loss-of-function alleles tested are not clinically important in this context or because the 2 trials had differences in racial/ethnic composition. Additionally, differences between the 2 trials might be due to chance as our statistical power was limited to 50%.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT00991029.

Risk for Major Hemorrhages in Patients Receiving Clopidogrel and Aspirin Compared With Aspirin Alone After Transient Ischemic Attack or Minor Ischemic Stroke: A Secondary Analysis of the POINT Randomized Clinical Trial

Importance

Results show the short-term risk of hemorrhage in treating patients with acute transient ischemic attack (TIA) or minor acute ischemic stroke (AIS) with clopidogrel plus aspirin or aspirin alone.

Objective

To characterize the frequency and kinds of major hemorrhages in the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial.

Design, Setting, and Participants

This secondary analysis of the POINT randomized, double-blind clinical trial conducted in 10 countries in North America, Europe, and Australasia included patients with high-risk TIA or minor AIS who were randomized within 12 hours of symptom onset and followed up for 90 days. The total enrollment, which occurred from May 28, 2010, through December 17, 2017, was 4881 and constituted the intention-to-treat group; 4819 (98.7%) were included in the as-treated analysis group. The primary safety analyses were as-treated, classifying patients based on study drug actually received. Intention-to-treat analyses were performed as secondary analyses. Data were analyzed in April 2018.

Interventions

Patients were assigned to receive clopidogrel (600 mg loading dose on day 1 followed by 75 mg daily for days 2-90) or placebo; all patients also received open-label aspirin, 50 to 325 mg/d.

Main Outcomes and Measures

The primary safety outcome was all major hemorrhages. Other safety outcomes included minor hemorrhages.

Results

A total of 269 sites worldwide randomized 4881 patients (median age, 65.0 years [interquartile range, 55-74 years]; 2195 women [45.0%]); the primary results have been published previously. In the as-treated analyses, major hemorrhage occurred in 21 patients (0.9%) receiving clopidogrel plus aspirin and 6 (0.2%) in the aspirin alone group (hazard ratio, 3.57; 95% CI, 1.44-8.85; P = .003; number needed to harm, 159). There were 4 fatal hemorrhages (0.1%; 3 in the clopidogrel plus aspirin group and 1 in the aspirin alone group); 3 of the 4 were intracranial. There were 7 intracranial hemorrhages (0.1%); 5 were in the clopidogrel plus aspirin group and 2 in the aspirin plus placebo group. The most common location of major hemorrhages was in the gastrointestinal tract.

Conclusions and Relevance

The risk for major hemorrhages in patients receiving either clopidogrel plus aspirin or aspirin alone after TIA or minor AIS was low. Nevertheless, treatment with clopidogrel plus aspirin increased the risk of major hemorrhages over aspirin alone from 0.2% to 0.9%.

Trial Registration

ClinicalTrials.gov identifier: NCT00991029.

Antithrombotic Treatment of Embolic Stroke of Undetermined Source: RE-SPECT ESUS Elderly and Renally Impaired Subgroups

Background and Purpose- The RE-SPECT ESUS trial (Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate Versus Acetylsalicylic Acid in Patients With Embolic Stroke of Undetermined Source) tested the hypothesis that dabigatran would be superior to aspirin for the prevention of recurrent stroke in patients with embolic stroke of undetermined source. This exploratory subgroup analysis investigates the impact of age, renal function (both predefined), and dabigatran dose (post hoc) on the rates of recurrent stroke and major bleeding. Methods- RE-SPECT ESUS was a multicenter, randomized, double-blind trial of dabigatran 150 or 110 mg (for patients aged ≥75 years and/or with creatinine clearance 30 to <50 mL/minute) twice daily compared with aspirin 100 mg once daily. The primary outcome was recurrent stroke. Results- The trial, which enrolled 5390 patients from December 2014 to January 2018, did not demonstrate superiority of dabigatran versus aspirin for prevention of recurrent stroke in patients with embolic stroke of undetermined source. However, among the population qualifying for the lower dabigatran dose, the rate of recurrent stroke was reduced with dabigatran versus aspirin (7.4% versus 13.0%; hazard ratio, 0.57 [95% CI, 0.39-0.82]; interaction P=0.01). This was driven mainly by the subgroup aged ≥75 years (7.8% versus 12.4%; hazard ratio, 0.63 [95% CI, 0.43-0.94]; interaction P=0.10). Stroke rates tended to be lower with dabigatran versus aspirin with declining renal function. Risks for major bleeding were similar between treatments, irrespective of renal function, but with a trend for lower bleeding rates with dabigatran versus aspirin in older patients. Conclusions- In subgroup analyses of RE-SPECT ESUS, dabigatran reduced the rate of recurrent stroke compared with aspirin in patients qualifying for the lower dose of dabigatran. These results are hypothesis-generating. Aspirin remains the standard antithrombotic treatment for patients with embolic stroke of undetermined source. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239120.

Disability After Minor Stroke and Transient Ischemic Attack in the POINT Trial

Background and Purpose- While combination aspirin and clopidogrel reduces recurrent stroke compared with aspirin alone in patients with transient ischemic attack (TIA) or minor stroke, the effect on disability is uncertain. Methods- The POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke) randomized patients with TIA or minor stroke (National Institutes of Health Stroke Scale score ≤3) within 12 hours of onset to dual antiplatelet therapy (DAPT) with aspirin plus clopidogrel versus aspirin alone. The primary outcome measure was a composite of stroke, myocardial infarction, or vascular death. We performed a post hoc exploratory analysis to examine the effect of treatment on overall disability (defined as modified Rankin Scale score >1) at 90 days, as well as disability ascribed by the local investigator to index or recurrent stroke. We also evaluated predictors of disability. Results- At 90 days, 188 of 1964 (9.6%) of patients enrolled with TIA and 471 of 2586 (18.2%) of those enrolled with stroke were disabled. Overall disability was similar between patients assigned DAPT versus aspirin alone (14.7% versus 14.3%; odds ratio, 0.97 [95% CI, 0.82-1.14]; P=0.69). However, there were numerically fewer patients with disability in conjunction with a primary outcome event in the DAPT arm (3.0% versus 4.0%; odds ratio, 0.73 [95% CI, 0.53-1.01]; P=0.06) and significantly fewer patients in the DAPT arm with disability attributed by the investigators to either the index event or recurrent stroke (5.9% versus 7.4%; odds ratio, 0.78 [95% CI, 0.62-0.99]; P=0.04). Notably, disability attributed to the index event accounted for the majority of this difference (4.5% versus 6.0%; odds ratio, 0.74 [95% CI, 0.57-0.96]; P=0.02). In multivariate analysis, age, subsequent ischemic stroke, serious adverse events, and major bleeding were significantly associated with disability in TIA; for those with stroke, female sex, hypertension, or diabetes mellitus, National Institutes of Health Stroke Scale score, recurrent ischemic stroke, subsequent myocardial infarction, and serious adverse events were associated with disability. Conclusions- In addition to reducing recurrent stroke in patients with acute minor stroke and TIA, DAPT might reduce stroke-related disability. Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT00991029.

Abstract 104: Disability After Minor Stroke and TIA in the POINT Trial

Background and Purpose: To assess the effect of combination antiplatelet therapy with aspirin and clopidogrel versus aspirin alone on disability following TIA or minor stroke and to identify factors associated with disability.

Methods: The POINT trial randomized patients with TIA or minor stroke (NIHSS≤3) within 12 hours of onset to dual antiplatelet therapy (DAPT) with aspirin plus clopidogrel versus aspirin alone. The primary outcome measure was a composite of stroke, MI, or vascular death. We performed a post-hoc exploratory analysis to examine the effect of treatment on overall disability (defined as mRS>1) at 90 days as well as disability ascribed by the local investigator to index or recurrent stroke. We also evaluated predictors of disability.

Results: At 90 days, 188/1964 (9.6%) of patients enrolled with TIA and 471/2586 (18.2%) of those enrolled with stroke were disabled. Overall disability was similar between patients assigned DAPT versus aspirin alone (14.7% vs. 14.3%, OR 0.97, 95%CI 0.82-1.14, p=0.69). However, there were numerically fewer patients with disability in conjunction with a primary outcome event in the DAPT arm (3.0% vs. 4.0%, OR 0.73, 95%CI 0.53-1.01, p=0.06), and significantly fewer patients in the DAPT arm with disability attributed by the investigators to either the index event or recurrent stroke (5.9% vs. 7.4%, OR 0.78, 95% CI 0.62-0.99, p=0.04). Notably, disability attributed to the index event accounted for the majority of this difference (4.5% vs. 6.0%, OR 0.74 95% CI 0.57-0.96, p=0.02). In multivariate analysis of patients enrolled with TIA, disability was significantly associated with age, subsequent ischemic stroke, serious adverse events, and major bleeding. In patients enrolled with stroke, disability was associated with female sex, hypertension, diabetes, NIHSS score, recurrent ischemic stroke, subsequent myocardial infarction, and serious adverse events.

Conclusions: In addition to reducing recurrent stroke in patients with acute minor stroke and TIA, dual antiplatelet therapy might reduce stroke-related disability.

286Predictors of atrial fibrillation in patients with embolic stroke of undetermined source: an analysis of the RE-SPECT ESUS trial

Background

A proportion of patients with embolic stroke of undetermined source (ESUS) may have silent atrial fibrillation (AF) or develop AF after the initial evaluation. Better understanding of risk for identification is critical to implement optimal monitoring strategies with the goal of preventing recurrent stroke. The RE-SPECT ESUS trial provides an opportunity to assess predictors for developing AF and associated recurrent stroke.

Methods

RE-SPECT ESUS was a randomized, controlled trial (564 sites, 42 countries) assessing dabigatran versus aspirin for the prevention of recurrent stroke in patients with ESUS. Of 5390 patients enrolled and followed for a median of 19 months, 403 (7.5%) were found to develop AF reported as an adverse event or using cardiac monitoring per standard clinical care. Univariable and multivariable regression analyses for predictors of AF were conducted.

Results

In a multivariable analysis, clinical predictors for developing AF were: older age, history of heart failure, lower heart rate, hypertension, higher body mass index, and being from Western Europe (Table). Using several published predictive models, including HAVOC, C2HEST, AS5F, ARIC, and CHA2DS2-VASc, high scores were associated with increased rates of AF. In patients who developed AF, recurrent stroke occurred in 7.0% per year, versus 4.2% per year in patients who did not develop AF (hazard ratio 1.75; 95% CI 1.30–2.35, p=0.0002).

Conclusion

Besides age as the most important variable, several other factors, including lower heart rate, higher body mass index, and hypertension, are independent predictors of AF after ESUS. Understanding who is at higher risk of developing AF may help identify patients requiring more intense, long-term cardiac monitoring.

Acknowledgement/Funding

Funded by Boehringer Ingelheim

Assessment of the End Point Adjudication Process on the Results of the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trial: A Secondary Analysis

IMPORTANCE

Debate continues about the value of event adjudication in clinical trials and whether independent centralized assessments improve reliability and validity of study results in masked randomized trials compared with local, investigator-assessed end points.

OBJECTIVE

To assess the results of the adjudicated end point process in the Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial by comparing end points assessed by local site investigators with centrally adjudicated end points.

DESIGN, SETTING, AND PARTICIPANTS

This is an ad hoc secondary analysis of a randomized, double-blind clinical trial comparing safety and effectiveness of clopidogrel bisulphate plus aspirin vs placebo plus aspirin. Patients received either 600 mg of clopidogrel bisulphate on day 1, then 75 mg per day through day 90 plus 50 to 325 mg of aspirin per day, or the same range of dosages of placebo plus aspirin. Investigators reported all potential end points; independent masked adjudicators were randomly assigned to review using definitions specified in the study protocol. This was a multicenter study; 269 international sites in 10 countries enrolled from May 28, 2010, to December 19, 2017. The study enrolled 4881 patients 18 years or older with transient ischemic attack or minor acute ischemic stroke within 12 hours of symptom onset and followed for 90 days from randomization; last follow-up was completed in March 2018.

MAIN OUTCOMES AND MEASURES

Independent adjudicators external to the study and masked to study treatment assignment adjudicated 467 primary and secondary effectiveness outcomes and major and minor bleeding events, including the primary composite end point, which was the risk of a composite of major ischemic events at 90 days, defined as ischemic stroke, myocardial infarction, or death from an ischemic vascular event. The primary safety end point was major hemorrhage. All components of the primary and safety outcomes were adjudicated.

RESULTS

In this secondary analysis of an international randomized clinical trial, a total of 269 sites worldwide randomized 4881 patients (median age, 65.0 years; interquartile range, 55-74 years); 55.0% were male. The primary results have been published previously. The hazard ratios for clopidogrel plus aspirin vs placebo plus aspirin for the primary composite end point were 0.75 (95% CI, 0.59-0.95) for adjudicator-assessed events and 0.76 (95% CI, 0.60-0.95) for investigator-assessed events. Agreement between adjudicator and investigator assessments was 90.7%. The hazard ratios for clopidogrel plus aspirin vs placebo plus aspirin for the primary safety end point were 2.32 (95% CI, 1.10-4.87) for adjudicator-assessed events and 2.58 (95% CI, 1.19-5.58) for investigator-assessed events, with an agreement rate of 77.5%.

CONCLUSIONS AND RELEVANCE

Independent end point adjudication did not substantially alter estimates of the primary treatment effectiveness in the POINT trial.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00991029.

Time Course for Benefit and Risk of Clopidogrel and Aspirin After Acute Transient Ischemic Attack and Minor Ischemic Stroke

BACKGROUND

In patients with acute minor ischemic stroke or high-risk transient ischemic attack enrolled in the POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke [POINT] Trial), the combination of clopidogrel and aspirin for 90 days reduced major ischemic events but increased major hemorrhage in comparison to aspirin alone.

METHODS

In a secondary analysis of POINT (N=4881), we assessed the time course for benefit and risk from the combination of clopidogrel and aspirin. The primary efficacy outcome was a composite of ischemic stroke, myocardial infarction, or ischemic vascular death. The primary safety outcome was major hemorrhage. Risks and benefits were estimated for delayed times of treatment initiation using left-truncated models.

RESULTS

Through 90 days, the rate of major ischemic events was initially high then decreased markedly, whereas the rate of major hemorrhage remained low but relatively constant throughout. With the use of a model-based approach, the optimal change point for major ischemic events was 21 days (0-21 days hazard ratio 0.65 for clopidogrel-aspirin versus aspirin; 95% CI, 0.50-0.85; P=0.0015, in comparison to 22-90 days hazard ratio, 1.38; 95% CI, 0.81-2.35; P=0.24). Models showed benefits of clopidogrel-aspirin for treatment delayed as long as 3 days after symptom onset.

CONCLUSIONS

The benefit of clopidogrel-aspirin occurs predominantly within the first 21 days, and outweighs the low, but ongoing risk of major hemorrhage. When considered with the results of the CHANCE trial (Clopidogrel in High-Risk Patients With Non-disabling Cerebrovascular Events), a similar trial treating with clopidogrel-aspirin for 21 days and showing no increase in major hemorrhage, these results suggest that limiting clopidogrel-aspirin use to 21 days may maximize benefit and reduce risk after high-risk transient ischemic attack or minor ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00991029.

Estimated treatment effect of ticagrelor versus aspirin by investigator-assessed events compared with judgement by an independent event adjudication committee in the SOCRATES trial

BACKGROUND

Adjudication of endpoints is a standard procedure in cardiovascular clinical trials. However, several studies indicate that the benefit of adjudication in estimating treatment effect may be limited.

AIMS

This post hoc analysis of SOCRATES (NCT01994720) compared the treatment effects and investigated the agreement of clinical event assessment by site investigators and independent adjudicators.

METHODS

SOCRATES compared ticagrelor and aspirin in 13,199 patients with acute minor stroke or high-risk transient ischemic attack. The primary endpoint was stroke, myocardial infarction, or death. Stroke was the major component of the primary endpoint and a secondary endpoint. The endpoints were adjudicated by a blinded independent committee. We compared the treatment effect on the primary endpoint and stroke alone based on the investigators' and adjudicators' assessments, and investigated the agreement rate on the stroke endpoint and major hemorrhages.

RESULTS

The hazard ratios (95% confidence interval) for ticagrelor versus aspirin therapy for the primary endpoint were 0.89 (0.78-1.01) when calculated on adjudicator-assessed events and 0.88 (0.78-1.00) for investigator-assessed events. The hazard ratios (95% confidence intervals) for stroke were 0.86 (0.75-0.99) based on the adjudicators' diagnoses and 0.85 (0.75-0.97) based on the investigators' diagnoses. The overall agreement between adjudicator- and investigator-diagnosed stroke was 91%, and for major hemorrhages was 88%.

CONCLUSIONS

In SOCRATES, there was no clinically meaningful difference in the estimated treatment effect, on either the primary endpoint or stroke, by using investigator- or adjudicator-assessed events. Double-blind treatment outcome studies with stroke endpoints may not benefit from adjudication.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01994720.

Dabigatran for Prevention of Stroke after Embolic Stroke of Undetermined Source

BACKGROUND

Cryptogenic strokes constitute 20 to 30% of ischemic strokes, and most cryptogenic strokes are considered to be embolic and of undetermined source. An earlier randomized trial showed that rivaroxaban is no more effective than aspirin in preventing recurrent stroke after a presumed embolic stroke from an undetermined source. Whether dabigatran would be effective in preventing recurrent strokes after this type of stroke was unclear.

METHODS

We conducted a multicenter, randomized, double-blind trial of dabigatran at a dose of 150 mg or 110 mg twice daily as compared with aspirin at a dose of 100 mg once daily in patients who had had an embolic stroke of undetermined source. The primary outcome was recurrent stroke. The primary safety outcome was major bleeding.

RESULTS

A total of 5390 patients were enrolled at 564 sites and were randomly assigned to receive dabigatran (2695 patients) or aspirin (2695 patients). During a median follow-up of 19 months, recurrent strokes occurred in 177 patients (6.6%) in the dabigatran group (4.1% per year) and in 207 patients (7.7%) in the aspirin group (4.8% per year) (hazard ratio, 0.85; 95% confidence interval [CI], 0.69 to 1.03; P = 0.10). Ischemic strokes occurred in 172 patients (4.0% per year) and 203 patients (4.7% per year), respectively (hazard ratio, 0.84; 95% CI, 0.68 to 1.03). Major bleeding occurred in 77 patients (1.7% per year) in the dabigatran group and in 64 patients (1.4% per year) in the aspirin group (hazard ratio, 1.19; 95% CI, 0.85 to 1.66). Clinically relevant nonmajor bleeding occurred in 70 patients (1.6% per year) and 41 patients (0.9% per year), respectively.

CONCLUSIONS

In patients with a recent history of embolic stroke of undetermined source, dabigatran was not superior to aspirin in preventing recurrent stroke. The incidence of major bleeding was not greater in the dabigatran group than in the aspirin group, but there were more clinically relevant nonmajor bleeding events in the dabigatran group. (Funded by Boehringer Ingelheim; RE-SPECT ESUS ClinicalTrials.gov number, NCT02239120.).

Time to Loading Dose and Risk of Recurrent Events in the SOCRATES Trial

Background and Purpose- Recurrent ischemia risk is high in the acute period after cerebral ischemic events. Effects of antiplatelet agents may vary by time to loading dose (TLD). We explored the risk of recurrent events and safety and efficacy of ticagrelor versus aspirin in relation to TLD. Methods- We randomized 13 199 patients with noncardioembolic, nonsevere ischemic stroke, or high-risk transient ischemic attack to 90-day ticagrelor or aspirin treatment within 24 hours of symptom onset. For this analysis, 13 126 patients were categorized by TLD as <12 hours or ≥12 hours from start of index event. The primary end point was the composite of stroke, myocardial infarction, or death within 90 days. Major bleeding was the primary safety end point. Results- TLD was <12 hours in 4403 (33.5%) and ≥12 hours in 8723 (66.5%). The Kaplan-Meier% for the primary end point for all patients with TLD<12 hours was 7.5% versus 6.9% in TLD≥12 hours. Among patients with TLD<12 hours, the primary end point occurred in 147/2196 (6.8%) randomized to ticagrelor and in 184/2207 (8.3%) randomized to aspirin (hazard ratio, 0.79; 95% CI, 0.64-0.98; P=0.036). Among patients with TLD≥12 hours, the primary end point occurred in 6.7% patients randomized to ticagrelor versus 7.0% to aspirin (hazard ratio, 0.95; 95% CI, 0.81-1.12; P=0.55). There was no significant treatment-by-TLD interaction. Major bleeding rates were comparable on ticagrelor and aspirin, regardless of TLD. Conclusions- The event rate for the primary end point was higher in patients treated early (<12 hours) versus later (≥12 hours). In this exploratory analysis, a larger numerical difference in the primary end point was observed among patients on ticagrelor than on aspirin when TLD was <12 hours compared with ≥12 hours, although the interaction terms for treatment-by-TLD were not significant. For major bleeding, no relation to TLD was observed. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT01994720.

New opportunities to optimize antithrombotic therapy for secondary stroke prevention

Stroke symptoms can be unsettling, even when symptoms resolve, but focusing on stroke prevention can be empowering provided that effective interventions for appropriate patient populations are available. Current options include interventions for symptomatic carotid artery stenosis, anticoagulation for atrial fibrillation, high-dose statins, new oral anticoagulants, new developments in atrial fibrillation detection, and new therapeutics are in development. For antiplatelet therapy, aspirin monotherapy is effective but dual antiplatelet therapy with the combination of aspirin and clopidogrel increases hemorrhage risks over the long term that outweigh potential benefits. In the short term though, both the Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events (CHANCE) and Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trials have shown a benefit of short-term dual-antiplatelet therapy, though the increased major hemorrhage risk seen in POINT could justify applying dual-antiplatelet therapy to just the first 21 days. Furthermore, since clopidogrel is a prodrug that must be metabolized to have antiplatelet activity, it is not surprising that the treatment effect in CHANCE was limited to patients who were not carriers of loss-of-function alleles for clopidogrel metabolism. Ticagrelor, an antiplatelet agent which failed to meet its primary endpoint as monotherapy compared to aspirin in the Acute Stroke or Transient Ischaemic Attack Treated with Aspirin or Ticagrelor and Patient Outcomes (SOCRATES) trial, is currently being tested as combination therapy with aspirin compared to aspirin alone in Acute Stroke or Transient Ischaemic Attack Treated With Ticagrelor and ASA for Prevention of Stroke and Death (THALES). These developments along with improvements to the infrastructure to perform rapid evaluations and to apply intensive secondary stroke prevention interventions hold continued promise for the future.

Non-vitamin-K oral anticoagulants (NOACs) for the prevention of secondary stroke

INTRODUCTION

In patients with atrial fibrillation (AF), oral anticoagulation with vitamin K antagonists (VKA) (warfarin, phenprocoumon) is effective both for primary and secondary stroke prevention with a 60-70% relative reduction in stroke risk compared with placebo. Mortality is reduced by 26%. VKA have a number of well-documented shortcomings which were overcome by non-vitamin-K oral anticoagulants (NOACs). Areas covered: Results of randomized trials for four NOACs (apixaban, dabigatran, edoxaban, rivaroxaban) have been published (ARISTOTLE, RE-LY, ENGAGE, ROCKET-AF). In this review, the authors discuss the results in subgroups of patients with prior transient ischemic attacks or ischemic stroke. In aggregate, the NOACs are superior to warfarin for secondary prevention and result in a 50% reduction in intracerebral hemorrhage. Apixaban was superior to aspirin in the AVERROES trial and had a similar rate of major bleeding complications. Expert opinion: NOACs add to the therapeutic options for secondary stroke prevention in patients with AF and offer advantages over warfarin including a favorable bleeding profile and convenience of use. Aspirin should no longer be used for secondary stroke prevention in patients with AF.

Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA

BACKGROUND

Combination antiplatelet therapy with clopidogrel and aspirin may reduce the rate of recurrent stroke during the first 3 months after a minor ischemic stroke or transient ischemic attack (TIA). A trial of combination antiplatelet therapy in a Chinese population has shown a reduction in the risk of recurrent stroke. We tested this combination in an international population.

METHODS

In a randomized trial, we assigned patients with minor ischemic stroke or high-risk TIA to receive either clopidogrel at a loading dose of 600 mg on day 1, followed by 75 mg per day, plus aspirin (at a dose of 50 to 325 mg per day) or the same range of doses of aspirin alone. The dose of aspirin in each group was selected by the site investigator. The primary efficacy outcome in a time-to-event analysis was the risk of a composite of major ischemic events, which was defined as ischemic stroke, myocardial infarction, or death from an ischemic vascular event, at 90 days.

RESULTS

A total of 4881 patients were enrolled at 269 international sites. The trial was halted after 84% of the anticipated number of patients had been enrolled because the data and safety monitoring board had determined that the combination of clopidogrel and aspirin was associated with both a lower risk of major ischemic events and a higher risk of major hemorrhage than aspirin alone at 90 days. Major ischemic events occurred in 121 of 2432 patients (5.0%) receiving clopidogrel plus aspirin and in 160 of 2449 patients (6.5%) receiving aspirin plus placebo (hazard ratio, 0.75; 95% confidence interval [CI], 0.59 to 0.95; P=0.02), with most events occurring during the first week after the initial event. Major hemorrhage occurred in 23 patients (0.9%) receiving clopidogrel plus aspirin and in 10 patients (0.4%) receiving aspirin plus placebo (hazard ratio, 2.32; 95% CI, 1.10 to 4.87; P=0.02).

CONCLUSIONS

In patients with minor ischemic stroke or high-risk TIA, those who received a combination of clopidogrel and aspirin had a lower risk of major ischemic events but a higher risk of major hemorrhage at 90 days than those who received aspirin alone. (Funded by the National Institute of Neurological Disorders and Stroke; POINT ClinicalTrials.gov number, NCT00991029 .).

Efficacy and Safety of Ticagrelor in Relation to Aspirin Use Within the Week Before Randomization in the SOCRATES Trial

BACKGROUND AND PURPOSE

SOCRATES (Acute Stroke or Transient Ischemic Attack Treated With Aspirin or Ticagrelor and Patient Outcomes), comparing ticagrelor with aspirin in patients with acute cerebral ischemia, found a nonsignificant 11% relative risk reduction for stroke, myocardial infarction, or death (P=0.07). Aspirin intake before randomization could enhance the effect of ticagrelor by conferring dual antiplatelet effect during a high-risk period for subsequent stroke. Therefore, we explored the efficacy and safety of ticagrelor versus aspirin in the patients who received any aspirin the week before randomization.

METHODS

A prespecified subgroup analysis in SOCRATES (n=13 199), randomizing patients with acute ischemic stroke (National Institutes of Health Stroke Scale score of ≤5) or transient ischemic attack (ABCD² score of ≥4) to 90-day treatment with ticagrelor or aspirin. Patients in the prior-aspirin group had received any aspirin within the week before randomization. Primary end point was time to stroke, myocardial infarction, or death. Safety end point was PLATO (Study of Platelet Inhibition and Patient Outcomes) major bleeding.

RESULTS

The 4232 patients in the prior-aspirin group were older, had more vascular risk factors, and vascular disease than the other patients. In the prior-aspirin group, the primary end point occurred in 138/2130 (6.5%) of patients on ticagrelor and in 177/2102 (8.3%) on aspirin (hazard ratio, 0.76; 95% confidence interval, 0.61-0.95; P=0.02); in patients with no prior-aspirin usage an event occurred in 304/4459 (6.9%) and 320/4508 (7.1%) on ticagrelor and aspirin, respectively (hazard ratio, 0.96; 95% confidence interval, 0.82-1.12; P=0.59). The treatment-by-prior-aspirin interaction was not statistically significant (P=0.10). In the prior-aspirin group, major bleeding occurred in 0.7% and 0.4% of patients on ticagrelor and aspirin, respectively (hazard ratio, 1.58; 95% confidence interval, 0.68-3.65; P=0.28).

CONCLUSIONS

In this secondary analysis from SOCRATES, fewer primary end points occurred on ticagrelor treatment than on aspirin in patients receiving aspirin before randomization, but there was no significant treatment-by-prior-aspirin interaction. A new study will investigate the benefit-risk of combining ticagrelor and aspirin in patients with acute cerebral ischemia (URL: https://www.clinicaltrials.gov. Unique identifier: NCT03354429).

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01994720.

Abstract WP394: Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trial

The P latelet- O riented I nhibition in N ew T IA and minor ischemic stroke (POINT) Trial is a prospective, randomized, double-blind, multicenter international trial with the primary null hypothesis that in patients with TIA or minor ischemic stroke treated with aspirin 50-325 mg/day, there is no difference in survival free of ischemic stroke, myocardial infarction, and ischemic vascular death at 90 days in those treated with clopidogrel (600 mg loading dose then 75 mg/day) compared to placebo when therapy is initiated within 12 hours of time last known free of new ischemic symptoms.

Methods: The primary endpoint is a composite outcome of new ischemic events: ischemic stroke, myocardial infarction or ischemic vascular death. Subjects are 18 years or older with high-risk TIA (ABCD 2 score ≥ 4) or minor ischemic stroke (NIHSS ≤ 3) meeting eligibility criteria who can be randomized within 12 hours of the qualifying event. Follow-up is 90 days from randomization so event rates are high throughout the period of study. A total of 5,840 patients will be recruited. The first subject was enrolled on May 28, 2010; international sites joined in August 2013.

Principal Investigator: S. Claiborne Johnston, MD, PhD, The University of Texas at Austin

Co-Principal Investigators: J. Donald Easton, MD, University of California, San Francisco; Anthony S. Kim, MD, MAS, University of California, San Francisco

Contact: Mary Farrant, MBA, BSN, RN, University of California, San Francisco, Director, POINT Trial —UCSF Clinical Coordinating Center (CCC), San Francisco, California, 94158; Phone: 1-415-502-7304; Email: mary.farrant2@ucsf.edu

Planned Number of Centers: 225; Present Number: 195

Planned Number of Subjects: 5,840; Present Number: 4,586 (June 2017)

Sponsor: University of California, San Francisco (UCSF); National Institute of Neurological Disorders and Stroke (NINDS)

Collaborators: Neurological Emergencies Treatment Trials Network (NETT); Statistics and Data Management Center (SDMC) at Medical University of South Carolina (MUSC); POINT Clinical Research Collaboration (POINT-CRC) at EMMES Corporation

Dates of Study: October 2009 - April 2021

ClinicalTrials.gov Identifier: NCT00991029 http://clinicaltrials.gov/ct2/show/NCT00991029?term=POINT&rank=1

Ticagrelor Versus Aspirin in Acute Embolic Stroke of Undetermined Source

BACKGROUND AND PURPOSE

Ticagrelor is an effective antiplatelet therapy among patients with atherosclerotic disease and, therefore, could be more effective than aspirin in preventing recurrent stroke and cardiovascular events among patients with embolic stroke of unknown source (ESUS), which includes patients with ipsilateral stenosis <50% and aortic arch atherosclerosis.

METHODS

We randomized 13 199 patients with a noncardioembolic, nonsevere ischemic stroke or high-risk transient ischemic attack to ticagrelor (180 mg loading dose on day 1 followed by 90 mg twice daily for days 2-90) or aspirin (300 mg on day 1 followed by 100 mg daily for days 2-90) within 24 hours of symptom onset. In all patients, investigators informed on the presence of ipsilateral stenosis ≥50%, small deep infarct <15 mm, and on cardiac source of embolism detected after enrollment or rare causes, which allowed to construct an ESUS category in all other patients with documented brain infarction. The primary end point was the time to the occurrence of stroke, myocardial infarction, or death within 90 days.

RESULTS

ESUS was identified in 4329 (32.8%) patients. There was no treatment-by-ESUS category interaction (P=0.83). Hazard ratio in ESUS patients was 0.87 (95% confidence interval, 0.68-1.10; P=0.24). However, hazard ratio was 0.51 (95% confidence interval, 0.29-0.90; P=0.02) in ESUS patients with ipsilateral stenosis <50% or aortic arch atherosclerosis (n=961) and 0.98 (95% confidence interval, 0.76-1.27; P=0.89) in the remaining ESUS patients (n=3368; P for heterogeneity =0.04).

CONCLUSIONS

In this post hoc, exploratory analysis, we found no treatment-by-ESUS category interaction. ESUS subgroups have heterogeneous response to treatment (Funded by AstraZeneca).

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01994720.

Abstract TMP16: Efficacy and Safety of Ticagrelor in Relation to Time to Loading Dose in the SOCRATES Trial

Background: The risk of recurrent ischemia is high in the acute period after transient ischemic attack (TIA) and minor stroke. Therefore, event rates and treatment effects may vary in relation to time to loading dose (TLD) of antiplatelet treatment. We aimed to explore safety and efficacy of ticagrelor in relation to TLD from the onset of the index event.

Methods: In the SOCRATES trial (NCT01994720), we randomized 13,199 patients with a non-cardioembolic, non-severe ischemic stroke or high-risk TIA to ticagrelor (180 mg loading dose on day 1, followed by 90 mg twice daily for days 2-90) or aspirin (300 mg on day 1, followed by 100 mg daily for days 2-90) within 24 hours of symptom onset. Ticagrelor was not found to be superior to aspirin in reducing the rate of the primary composite endpoint of stroke, myocardial infarction, or death at 90 days. Patients were categorized according to TLD as <12 h and ≥12h from index event for this pre-specified exploratory analysis. The primary endpoint was time to the occurrence of stroke, myocardial infarction, or death within 90 days. The first secondary endpoint was ischemic stroke, with major bleeding serving as the primary safety endpoint.

Results: TLD was <12 h in 4,403 (33.4%) and ≥12 h in 8,723 (66.1%). Among TLD <12 h patients, the primary endpoint occurred in 147/2196 (6.7%) patients randomized to ticagrelor and in 184/2207 (8.3%) randomized to aspirin (HR 0.79; 95% CI 0.64-0.98, p=0.036); ischemic stroke was less frequent in those treated with ticagrelor (6.0% vs 7.5%, HR 0.79; 95% CI 0.63-0.99, p=0.041). Among patients with TLD ≥12 h, there were no differences in the treatment groups for the primary endpoint (6.7 vs 7.0%) or for ischemic stroke (5.8% vs 6.2%). There were no significant treatment-by-TLD interactions. Major bleeding was comparable in TLD <12 h patients (0.5% vs 0.7%, p=0.25) and TLD ≥12 h (0.5% vs 0.5%, p=0.95) on ticagrelor and aspirin, respectively.

Conclusion: In this pre-specified exploratory analysis, ticagrelor showed a greater treatment effect over aspirin in patients with TLD <12 h, although the interaction terms for treatment by TLD were not significant. Event rates for primary and secondary endpoints tended to be higher in patients randomized <12 h. Major bleeding was unrelated to TLD.

Abstract TMP20: Efficacy and Safety of Ticagrelor in Relation to Prior Aspirin Usage in the SOCRATES Trial

Background: In the SOCRATES study (NCT01994720), addition of ticagrelor to patients on aspirin treatment before randomization may confer the effect of dual antiplatelet therapy as the antiplatelet effect of aspirin persists for more than a week. We aimed to explore safety and efficacy of ticagrelor in this pre-specified group of patients who had received aspirin prior to randomization.

Methods: We randomized 13,199 patients with a non-cardioembolic, non-severe ischemic stroke or high-risk transient ischemic attack (TIA) to ticagrelor (180mg loading dose on day 1 followed by 90mg twice daily for days 2-90) or aspirin (300mg on day 1 followed by 100mg daily for days 2-90) within 24 hours of symptom onset. The prior aspirin group consisted of patients who had received aspirin within 7 days before randomization. The primary endpoint was the time to the occurrence of stroke, myocardial infarction, or death within 90 days.

Results: The 4,232 patients with prior aspirin usage were older, had more vascular risk factors and vascular disease than the 8,967 patients with no prior aspirin usage. In the prior aspirin group, a primary endpoint occurred in 138/2,130 (6.5%) patients randomized to ticagrelor and in 177/2,102 (8.3%) patients randomized to aspirin (HR 0.76; 95% CI, 0.61-0.95, P=0.016) while for the non-aspirin group in 304/4,459 (6.9%) patients randomized to ticagrelor and in 320/4,508 (7.1%) patients randomized to aspirin (HR 0.96; 95%CI, 0.82-1.12, P=0.59). There was no significant treatment-by-prior-aspirin interaction (P=0.098). Major bleeding occurred in 0.7% of patients randomized to ticagrelor and in 0.4% randomized to aspirin (HR 1.58; 95% CI 0.68-3.65, P=0.28) in the prior aspirin group.

Conclusion: In this pre-specified exploratory analysis, ticagrelor showed a numerically greater treatment effect over aspirin in patients taking prior aspirin, although the interaction for treatment by prior aspirin was not statistically significant. Further study is needed to evaluate the combination of ticagrelor and aspirin in patients with minor stroke/TIA.

Ticagrelor in Acute Stroke or Transient Ischemic Attack in Asian Patients: From the SOCRATES Trial (Acute Stroke or Transient Ischemic Attack Treated With Aspirin or Ticagrelor and Patient Outcomes)

BACKGROUND AND PURPOSE

In the SOCRATES trial (Acute Stroke or Transient Ischemic Attack Treated With Aspirin or Ticagrelor and Patient Outcomes), ticagrelor was not superior to aspirin. Because of differences in patient demographics and stroke disease pattern in Asia, outcomes of ticagrelor versus aspirin were assessed among Asian patients in a prespecified exploratory analysis.

METHODS

Baseline demographics, treatment effects, and safety of ticagrelor and aspirin were assessed among Asian patients. Differences in outcomes between groups were assessed using Cox proportional hazard model.

RESULTS

A total of 3858 (29.2%) SOCRATES participants were recruited in Asia. Among the Asian patients, the primary end point event occurred in 186 (9.6%) of the 1933 patients treated with ticagrelor, versus 224 (11.6%) of the 1925 patients treated with aspirin (hazard ratio, 0.81; 95% confidence interval, 0.67-0.99). The exploratory P value for treatment-by-region interaction was 0.27. The primary end point event rate in the Asian subgroup was numerically higher than that in the non-Asian group (10.6% versus 5.7%; nominal P<0.01). Among the Asian patients, the rate of PLATO (Platelet Inhibition and Patient Outcomes)-defined major bleeding was similar in the ticagrelor group and the aspirin group (0.6% versus 0.8%; hazard ratio, 0.76; 95% confidence interval, 0.36-1.61).

CONCLUSIONS

The event rates were numerically higher in the Asian patients. Among the Asian patients with acute stroke or transient ischemic attacks, there was a trend toward a lower hazard ratio in reducing risk of the primary end point of stroke, myocardial infarction, or death in the ticagrelor group.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01994720.

Ticagrelor versus Aspirin in Acute Stroke or Transient Ischemic Attack

BACKGROUND

Ticagrelor may be a more effective antiplatelet therapy than aspirin for the prevention of recurrent stroke and cardiovascular events in patients with acute cerebral ischemia.

METHODS

We conducted an international double-blind, controlled trial in 674 centers in 33 countries, in which 13,199 patients with a nonsevere ischemic stroke or high-risk transient ischemic attack who had not received intravenous or intraarterial thrombolysis and were not considered to have had a cardioembolic stroke were randomly assigned within 24 hours after symptom onset, in a 1:1 ratio, to receive either ticagrelor (180 mg loading dose on day 1 followed by 90 mg twice daily for days 2 through 90) or aspirin (300 mg on day 1 followed by 100 mg daily for days 2 through 90). The primary end point was the time to the occurrence of stroke, myocardial infarction, or death within 90 days.

RESULTS

During the 90 days of treatment, a primary end-point event occurred in 442 of the 6589 patients (6.7%) treated with ticagrelor, versus 497 of the 6610 patients (7.5%) treated with aspirin (hazard ratio, 0.89; 95% confidence interval [CI], 0.78 to 1.01; P=0.07). Ischemic stroke occurred in 385 patients (5.8%) treated with ticagrelor and in 441 patients (6.7%) treated with aspirin (hazard ratio, 0.87; 95% CI, 0.76 to 1.00). Major bleeding occurred in 0.5% of patients treated with ticagrelor and in 0.6% of patients treated with aspirin, intracranial hemorrhage in 0.2% and 0.3%, respectively, and fatal bleeding in 0.1% and 0.1%.

CONCLUSIONS

In our trial involving patients with acute ischemic stroke or transient ischemic attack, ticagrelor was not found to be superior to aspirin in reducing the rate of stroke, myocardial infarction, or death at 90 days. (Funded by AstraZeneca; ClinicalTrials.gov number, NCT01994720.).

Design of Randomized, Double-Blind, Evaluation in Secondary Stroke Prevention Comparing the Efficacy and Safety of the Oral Thrombin Inhibitor Dabigatran Etexilate vs. Acetylsalicylic Acid in Patients with Embolic Stroke of Undetermined Source (Re-Spect Esus)

Rationale

Cryptogenic ischemic strokes constitute 20–30% of ischemic strokes, the majority of which are embolic strokes of undetermined source. The standard preventive treatment in these patients is usually acetylsalicylic acid.

Aim

The Randomized, double-blind, Evaluation in secondary Stroke Prevention comparing the EfficaCy and safety of the oral Thrombin inhibitor dabigatran etexilate vs. acetylsalicylic acid in patients with Embolic Stroke of Undetermined Source (RE-SPECT ESUS) is designed to determine whether the oral thrombin inhibitor dabigatran, taken within three-months after embolic stroke of undetermined source, is superior to acetylsalicylic acid for prevention of recurrent stroke and to characterize the safety of dabigatran in this setting.

Design

Prospective, randomized, double-blind, multicenter trial in approximately 6000 patients and 550 centers with embolic stroke of undetermined source. Subjects are randomized to dabigatran or acetylsalicylic acid and treated for an expected minimum of six-months and up to approximately three-years. It is an event-driven trial aiming for 353 adjudicated primary outcome events.

Study outcomes

The primary efficacy outcome is time to first recurrent stroke (ischemic, hemorrhagic, or unspecified). Key secondary outcomes are time to first ischemic stroke and time to first occurrence in the composite outcome of nonfatal stroke, nonfatal myocardial infarction, and cardiovascular death. The primary safety outcome is major hemorrhage, including symptomatic intracranial hemorrhage.

Discussion

Acetylsalicylic acid is the most common antithrombotic given to patients with embolic strokes of undetermined source to reduce recurrence risk. This trial will determine whether anticoagulation with dabigatran is more effective than acetylsalicylic acid, and acceptably safe.

Spontaneous echo-contrast in the internal jugular veins of patients with ischemic stroke

PURPOSE

Spontaneous echo-contrast (SEC) appears on B-mode images as moving curls of smoke in the lumen of veins. The aims of this study were to investigate the prevalence and characteristics of internal jugular vein SEC among patients with stroke, in comparison with control subjects.

METHODS

We enrolled 97 Korean patients with acute ischemic stroke and 50 controls. Both internal jugular veins were examined for the presence and severity of SEC and measurement of flow velocity. Venous samples were obtained for laboratory evaluation of hematologic factors.

RESULTS

In 294 internal jugular veins, the prevalence of SEC was 81% in stroke patients and 68% in controls (odds ratio, 2.0; 95% confidence interval, 1.1-3.6; p = 0.013). Stroke patients were more likely to have SEC on the left (p = 0.025) than on the right (p = 0.184) internal jugular vein. Overall, the association between stroke and SEC remained significant after adjustment for other variables (odds ratio, 4.3; 95% confidence interval, 1.7-10.8; p = 0.002).

CONCLUSIONS

Internal jugular vein SEC was found more frequently in stroke patients than in controls. However, local as well as systemic factors must be considered in the interpretation of this finding.

Acute Stroke or Transient Ischemic Attack Treated with Aspirin or Ticagrelor and Patient Outcomes (Socrates) Trial: Rationale and Design

Rationale

The risk of recurrent ischemia is high in the acute period after ischemic stroke and transient ischemic attack. Aspirin is recommended by guidelines for this indication, but more intensive antiplatelet therapy may be justified.

Aims

We aim to evaluate whether ticagrelor, a potent antiplatelet agent that blocks the P2Y12 receptor without requiring metabolic activation, reduces the risk of major vascular events compared with aspirin when randomization occurs within 24 h after symptom onset of a nonsevere ischemic stroke or high-risk transient ischemic attack.

Design

Acute Stroke or Transient Ischemic Attack Treated with Aspirin or Ticagrelor and Patient Outcomes (SOCRATES) is a randomized, double-blind, event-driven trial and will include an estimated 13 600 participants randomized in 33 countries worldwide to collect 844 primary events.

Study outcomes

The primary endpoint is the composite of stroke (ischemic or hemorrhagic), myocardial infarction, and death. Time to the first primary endpoint will be compared in the treatment groups during 90-day follow-up, with major hemorrhage serving as the primary safety endpoint. Participants will be followed for an additional 30 days after the randomized treatment period.

Discussion

The SOCRATES trial fulfills an important clinical need by evaluating a potent antiplatelet agent as a superior alternative to current standard of care in patients presenting acutely with ischemic stroke or transient ischemic attack.

Screen failure data in clinical trials: Are screening logs worth it?

BACKGROUND

Clinical trials frequently spend considerable effort to collect data on patients who were assessed for eligibility but not enrolled. The Consolidated Standards of Reporting Trials (CONSORT) guidelines' recommended flow diagram for randomized clinical trials reinforces the belief that the collection of screening data is a necessary and worthwhile endeavor. The rationale for collecting screening data includes scientific, trial management, and ethno-socio-cultural reasons.

PURPOSE

We posit that the cost of collecting screening data is not justified, in part due to inability to centrally monitor and verify the screening data in the same manner as other clinical trial data.

METHODS

To illustrate the effort and site-to-site variability, we analyzed the screening data from a multicenter, randomized clinical trial of patients with transient ischemic attack or minor ischemic stroke (Platelet-Oriented Inhibition in New Transient Ischemic Attack and Minor Ischemic Stroke (POINT)).

RESULTS

Data were collected on over 27,000 patients screened across 172 enrolling sites, 95% of whom were not enrolled. Although the rate of return of screen failure logs was high overall (95%), there were a considerable number of logs that were returned with 'no data to report' (23%), often due to administrative reasons rather than no patients screened.

CONCLUSION

In spite of attempts to standardize the collection of screening data, due to differences in site processes, multicenter clinical trials face challenges in collecting those data completely and uniformly. The efforts required to centrally collect high-quality data on an extensive number of screened patients may outweigh the scientific value of the data. Moreover, the lack of a standardized definition of 'screened' and the challenges of collecting meaningful characteristics for patients who have not signed consent limits the ability to compare across studies and to assess generalizability and selection bias as intended.

Embolic strokes of undetermined source: the case for a new clinical construct

Cryptogenic (of unknown cause) ischaemic strokes are now thought to comprise about 25% of all ischaemic strokes. Advances in imaging techniques and improved understanding of stroke pathophysiology have prompted a reassessment of cryptogenic stroke. There is persuasive evidence that most cryptogenic strokes are thromboembolic. The thrombus is thought to originate from any of several well established potential embolic sources, including minor-risk or covert cardiac sources, veins via paradoxical embolism, and non-occlusive atherosclerotic plaques in the aortic arch, cervical, or cerebral arteries. Accordingly, we propose that embolic strokes of undetermined source are a therapeutically relevant entity, which are defined as a non-lacunar brain infarct without proximal arterial stenosis or cardioembolic sources, with a clear indication for anticoagulation. Because emboli consist mainly of thrombus, anticoagulants are likely to reduce recurrent brain ischaemia more effectively than are antiplatelet drugs. Randomised trials testing direct-acting oral anticoagulants for secondary prevention of embolic strokes of undetermined source are warranted.

Platelet-oriented inhibition in new TIA and minor ischemic stroke (POINT) trial: rationale and design

BACKGROUND

Ischemic stroke and other vascular outcomes occur in 10-20% of patients in the three-months following a transient ischemic attack or minor ischemic stroke, and many are disabling. The highest risk period for these outcomes is the early hours and days immediately following the ischemic event. Aspirin is the most common antithrombotic treatment used for these patients.

AIM

The aim of POINT is to determine whether clopidogrel plus aspirin taken <12 h after transient ischemic attack or minor ischemic stroke symptom onset is more effective in preventing major ischemic vascular events at 90 days in the high-risk, and acceptably safe, compared with aspirin alone.

DESIGN

POINT is a prospective, randomized, double-blind, multicenter trial in patients with transient ischemic attack or minor ischemic stroke. Subjects are randomized to clopidogrel (600 mg loading dose followed by 75 mg/day) or matching placebo, and all will receive open-label aspirin 50-325 mg/day, with a dose of 162 mg daily for five-days followed by 81 mg daily strongly recommended.

STUDY OUTCOMES

The primary efficacy outcome is the composite of new ischemic vascular events - ischemic stroke, myocardial infarction, or ischemic vascular death - by 90 days. The primary safety outcome is major hemorrhage, which includes symptomatic intracranial hemorrhage.

DISCUSSION

Aspirin is the most common antithrombotic given to patients with a stroke or transient ischemic attack, as it reduces the risk of subsequent stroke. This trial expects to determine whether more aggressive antithrombotic therapy with clopidogrel plus aspirin, initiated acutely, is more effective than aspirin alone.