Hemorrhagic Transformation in Noncardioembolic Acute Ischemic Stroke: MRI Analysis From PACIFIC-STROKE

BACKGROUND

In the phase 2 PACIFIC-STROKE trial (Proper Dosing and Safety of the Oral FXIa Inhibitor BAY 2433334 in Patients Following Acute Noncardioembolic Stroke), asundexian, an oral factor XIa inhibitor, did not increase the risk of hemorrhagic transformation (HT). In this secondary analysis, we aimed to investigate the frequency, types, and risk factors of HT on brain magnetic resonance imaging (MRI).

METHODS

This was a secondary analysis of the PACIFIC-STROKE trial. Patients with mild-to-moderate acute noncardioembolic ischemic stroke were randomly assigned to asundexian or placebo plus guideline-based antiplatelet therapy. Brain MRIs were required at baseline (≤120 hours after stroke onset) and at 26 weeks or end-of-study. HT was defined using the Heidelberg classification and classified as early HT (identified on baseline MRI) or late HT (new HT by 26 weeks) based on iron-sensitive sequences. Multivariable logistic regression models were used to test factors that are associated with early HT and late HT, respectively.

RESULTS

Of 1745 patients with adequate baseline brain MRI (mean age, 67 years; mean National Institutes of Health Stroke Scale score, 2.8), early HT at baseline was detected in 497 (28.4%). Most were hemorrhagic infarctions (hemorrhagic infarction type 1: 15.2%; HI2: 12.7%) while a few were parenchymal hematomas (parenchymal hematoma type 1: 0.4%; parenchymal hematoma type 2: 0.2%). Early HT was more frequent with longer symptom onset-to-MRI interval. Male sex, diabetes, higher National Institutes of Health Stroke Scale large (>15 mm) infarct size, cortical involvement by infarct, higher number of acute infarcts, presence of chronic brain infarct, cerebral microbleed, and chronic cortical superficial siderosis were independently associated with early HT in the multivariable logistic regression model. Of 1507 with follow-up MRI, HT was seen in 642 (42.6%) overall, including 361 patients (23.9%) with late HT (new HT: 306; increased grade of baseline HT: 55). Higher National Institutes of Health Stroke Scale, large infarct size, cortical involvement of infarct, and higher number of acute infarcts predicted late HT.

CONCLUSIONS

About 28% of patients with noncardioembolic stroke had early HT, and 24% had late HT detectable by MRI. Given the high frequency of HT on MRI, more research is needed on how it influences treatment decisions and outcomes.

Chronic ischemic lesions and presence of patent foramen ovale in young adults with embolic stroke of undetermined source: Results of the young ESUS patient registry

BACKGROUND

Chronic ischemic lesions (CILs) are frequent findings in patients with acute ischemic stroke, but their phenotypes and relevance in young adults with embolic stroke of undetermined source (Y-ESUS) remains uncertain. We aimed to compare Y-ESUS patients with CIL to those without CIL and assessed the association of CIL and its phenotypes with the presence of patent foramen ovale (PFO).

METHODS

This prospective longitudinal, multicenter cohort study enrolled consecutive patients 50 years and younger with ESUS from October 2017 to October 2019 in 41 stroke research centers in 13 countries. Local investigators adjudicated presence and phenotypes of CIL on routine brain imaging (either magnetic resonance imaging (MRI) or computed tomography (CT)).

RESULTS

Overall, 535 patients were enrolled (mean age = 40.4 (standard deviation (SD) = 7.3) years, 238 (44%) female). CILs were present in 76/534 (14.2%) patients with a median count CIL count of 1.0 (interquartile range (IQR) = 1-2), 42/76 (55%) had at least one cortical phenotype and 38/76 (50%) at least one non-cortical phenotype. Y-ESUS with CIL were less often female (32% vs 47% in non-CIL Y-ESUS), were older (mean 43 vs 40 years), had more often hypertension (42% vs 19%), diabetes (17% vs 7%), and hyperlipidemia (34% vs 18%). CIL Y-ESUS were independently associated with lower stroke recurrence (relative risk (RR) = 0.17 (0.05-0.61)). In Y-ESUS with PFO, CILs were less frequent in probable pathogenic PFO than with probable non-pathogenic PFO (6.1% vs 30% p< 0.001).

CONCLUSION

One in seven Y-ESUS patients has additional CIL. CILs were associated with several vascular risk factors, lower probability of a pathogenic PFO, and lower stroke recurrence.

Bleeding Outcomes in Patients Treated With Asundexian in Phase II Trials

BACKGROUND

Phase II trials of asundexian were underpowered to detect important differences in bleeding.

OBJECTIVES

The goal of this study was to obtain best estimates of effects of asundexian vs active control/placebo on major and clinically relevant nonmajor (CRNM) and all bleeding, describe most common sites of bleeding, and explore association between asundexian exposure and bleeding.

METHODS

We performed a pooled analysis of 3 phase II trials of asundexian in patients with atrial fibrillation (AF), recent acute myocardial infarction (AMI), or stroke. Bleeding was defined according to the International Society on Thrombosis and Hemostasis (ISTH) criteria.

RESULTS

In patients with AF (n = 755), both asundexian 20 mg and 50 mg once daily vs apixaban had fewer major/CRNM events (3 of 249; incidence rate [IR] per 100 patient-years 5.47 vs 1 of 254 [IR: not calculable] vs 6 of 250 [IR: 11.10]) and all bleeding (12 of 249 [IR: 22.26] vs 10 of 254 [IR: 18.21] vs 26 of 250 [IR: 50.56]). In patients with recent AMI or stroke (n = 3,409), asundexian 10 mg, 20 mg, and 50 mg once daily compared with placebo had similar rates of major/CRNM events (44 of 840 [IR: 7.55] vs 42 of 843 [IR: 7.04] vs 56 of 845 [IR: 9.63] vs 41 of 851 [IR: 6.99]) and all bleeding (107 of 840 [IR: 19.57] vs 123 of 843 [IR: 22.45] vs 130 of 845 [IR: 24.19] vs 129 of 851 [IR: 23.84]). Most common sites of major/CRNM bleeding with asundexian were gastrointestinal, respiratory, urogenital, and skin. There was no significant association between asundexian exposure and major/CRNM bleeding.

CONCLUSIONS

Analyses of phase II trials involving >500 bleeds highlight the potential for improved safety of asundexian compared with apixaban and similar safety compared with placebo. Further evidence on the efficacy of asundexian awaits the results of ongoing phase III trials.

Effect of the Factor XIa Inhibitor Asundexian According to Baseline Infarct Pattern and on MRI Covert Infarct Outcomes

BACKGROUND

Exploratory analysis of the phase 2 PACIFIC-Stroke (Program of Anticoagulation via Inhibition of FXIa by the Oral Compound BAY 2433334-Non-Cardioembolic Stroke) randomized trial suggested that asundexian, an oral factor XIa inhibitor, prevents recurrent stroke and transient ischemic attacks in patients with atherosclerotic stroke. In this post hoc exploratory analysis, we hypothesized that asundexian would be more effective in patients enrolled with large, multiple, or cortical acute infarcts on magnetic resonance imaging than in patients enrolled with a single small subcortical acute infarct, and asundexian would prevent incident cortical covert infarcts.

METHODS

In this placebo-controlled double-blinded randomized controlled trial, patients with mild-to-moderate noncardioembolic ischemic stroke were assigned to asundexian (10, 20, or 50 mg once daily) or placebo, in addition to antiplatelet therapy. Brain magnetic resonance imagings were required within 72 hours of randomization and repeated at 26 weeks or at discontinuation of the study drug.

RESULTS

Of 1808 randomized patients, 1780 (98.5%) had interpretable baseline magnetic resonance imagings, of which 1628 (91.5%) had ≥1 diffusion-weighted imaging positive acute infarcts. Magnetic resonance imaging follow-up was obtained in 1439 patients, of whom 1358 had no symptomatic stroke during the trial period. Compared with placebo, asundexian 50 mg daily conferred a trend toward reduced risk of recurrent ischemic stroke or incident covert infarcts (hazard ratio, 0.71 [95% CI, 0.45-1.11]) and recurrent ischemic stroke or transient ischemic attack (secondary outcome; hazard ratio, 0.59 [95% CI, 0.33-1.06]) that was not evident in patients with single small subcortical infarcts (hazard ratios, 1.14 [95% CI, 0.62-2.10] and 0.93 [95% CI, 0.28-3.06]). Incident cortical covert infarcts were reduced in patients taking asundexian 50 mg, but the difference was not statistically significant (crude incidence ratio, 0.56 [95% CI, 0.28-1.12]).

CONCLUSIONS

These exploratory, unconfirmed results suggest that asundexian may prevent new embolic infarcts but not small artery occlusion. The hypothesis that subtypes of covert brain infarcts respond differently to anticoagulant prevention should be tested in future trials.

REGISTRATION

URL: https://clinicaltrials.gov; Unique identifier: NCT04304508.

Cerebral microbleeds and asundexian in non-cardioembolic ischemic stroke: Secondary analyses of the PACIFIC-STROKE randomized trial

BACKGROUND AND AIMS

Cerebral microbleeds are magnetic imaging resonance (MRI) markers of hemorrhage-prone cerebral small vessel disease that predict future risk of ischemic stroke and intracranial hemorrhage (ICrH). There exist concerns about the net benefit of antithrombotic therapy in patients with microbleeds. We aimed to investigate the effects of an oral factor-XIa inhibitor (asundexian), that is hypothesized to inhibit thrombosis without compromising hemostasis, on the development of new microbleeds over time and interactions between microbleeds and asundexian treatment on clinical outcomes. We additionally assessed associations between baseline microbleeds and the risks of clinical and neuroimaging outcomes in patients with non-cardioembolic ischemic stroke.

METHODS

This is a secondary analysis of the PACIFIC-STROKE, international, multi-center Phase 2b double-blind, randomized clinical trial. PACIFIC-STROKE enrolled patients aged ⩾ 45 years with mild-to-moderate non-cardioembolic ischemic stroke who presented within 48 h of symptom onset for whom antiplatelet therapy was intended. Microbleeds were centrally adjudicated, and participants with an interpretable T2*-weighted sequence at their baseline MRI were included in this analysis. Patients were randomized to asundexian (10/20/50 mg daily) versus placebo plus standard antiplatelet treatment. Regression models were used to estimate the effects of (1) all pooled asundexian doses and (2) asundexian 50 mg daily on new microbleed formation on 26-week MRIs. Cox proportional hazards or regression models were additionally used to estimate interactions between treatment assignment and microbleeds for ischemic stroke/transient ischemic attack (TIA) (primary outcome), and ICrH, all-cause mortality, hemorrhagic transformation (HT), and new microbleeds (secondary outcomes).

RESULTS

Of 1746 participants (mean age, 67.0 ± 10.0; 34% female) with baseline MRIs, 604 (35%) had microbleeds. During a median follow-up of 10.6 months, 7.0% (n = 122) had ischemic stroke/TIA, 0.5% (n = 8) ICrH, and 2.1% (n = 37) died. New microbleeds developed in 10.3% (n = 155) of participants with adequate follow-up MRIs and HT in 31.4% (n = 345). In the total sample of patients with adequate baseline and 26-week follow-up MRIs (n = 1507), new microbleeds occurred in 10.2% of patients assigned to any asundexian dose and 10.5% of patients assigned to placebo (OR, 0.96; 95% CI, 0.66-1.41). There were no interactions between microbleeds and treatment assignment for any of the outcomes (p for interaction > 0.05). The rates of new microbleeds, HT, and ICrH were numerically less in patients with microbleeds assigned to asundexian relative to placebo. The presence of microbleeds was associated with a higher risk of HT (aOR, 1.6; 95% CI, 1.2-2.1) and new microbleeds (aOR, 4.4; 95% CI, 3.0-6.3).

CONCLUSION

Factor XIa inhibition with asundexian appears safe in patients with non-cardioembolic ischemic stroke and hemorrhage-prone cerebral small vessel disease marked by microbleeds on MRI. These preliminary findings will be confirmed in the ongoing OCEANIC-STROKE randomized trial.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04304508.

Factor XIa inhibition with asundexian after acute non-cardioembolic ischaemic stroke (PACIFIC-Stroke): an international, randomised, double-blind, placebo-controlled, phase 2b trial

BACKGROUND

Asundexian (Bayer AG, Leverkusen, Germany), an oral small molecule factor XIa (FXIa) inhibitor, might prevent thrombosis without increasing bleeding. Asundexian's effect for secondary prevention of recurrent stroke is unknown.

METHODS

In this randomised, double-blind, placebo-controlled, phase 2b dose-finding trial (PACIFIC-Stroke), patients with acute (within 48 h) non-cardioembolic ischaemic stroke were recruited from 196 hospitals in 23 countries. Patients were eligible if they were aged 45 years or older, to be treated with antiplatelet therapy, and able to have a baseline MRI (either before or within 72 h of randomisation). Eligible participants were randomly assigned (1:1:1:1), using an interactive web-based response system and stratified according to anticipated antiplatelet therapy (single vs dual), to once daily oral asundexian (BAY 2433334) 10 mg, 20 mg, or 50 mg, or placebo in addition to usual antiplatelet therapy, and were followed up during treatment for 26-52 weeks. Brain MRIs were obtained at study entry and at 26 weeks or as soon as possible after treatment discontinuation. The primary efficacy outcome was the dose-response effect on the composite of incident MRI-detected covert brain infarcts and recurrent symptomatic ischaemic stroke at or before 26 weeks after randomisation. The primary safety outcome was major or clinically relevant non-major bleeding as defined by International Society on Thrombosis and Haemostasis criteria. The efficacy outcome was assessed in all participants assigned to treatment, and the safety outcome was assessed in all participants who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT04304508, and is now complete.

FINDINGS

Between June 15, 2020, and July 22, 2021, 1880 patients were screened and 1808 participants were randomly assigned to asundexian 10 mg (n=455), 20 mg (n=450), or 50 mg (n=447), or placebo (n=456). Mean age was 67 years (SD 10) and 615 (34%) participants were women, 1193 (66%) were men, 1505 (83%) were White, and 268 (15%) were Asian. The mean time from index stroke to randomisation was 36 h (SD 10) and median baseline National Institutes of Health Stroke Scale score was 2·0 (IQR 1·0-4·0). 783 (43%) participants received dual antiplatelet treatment for a mean duration of 70·1 days (SD 113·4) after randomisation. At 26 weeks, the primary efficacy outcome was observed in 87 (19%) of 456 participants in the placebo group versus 86 (19%) of 455 in the asundexian 10 mg group (crude incidence ratio 0·99 [90% CI 0·79-1·24]), 99 (22%) of 450 in the asundexian 20 mg group (1·15 [0·93-1·43]), and 90 (20%) of 447 in the asundexian 50 mg group (1·06 [0·85-1·32]; t statistic -0·68; p=0·80). The primary safety outcome was observed in 11 (2%) of 452 participants in the placebo group versus 19 (4%) of 445 in the asundexian 10 mg group, 14 (3%) of 446 in the asundexian 20 mg group, and 19 (4%) of 443 in the asundexian 50 mg group (all asundexian doses pooled vs placebo hazard ratio 1·57 [90% CI 0·91-2·71]).

INTERPRETATION

In this phase 2b trial, FXIa inhibition with asundexian did not reduce the composite of covert brain infarction or ischaemic stroke and did not increase the composite of major or clinically relevant non-major bleeding compared with placebo in patients with acute, non-cardioembolic ischaemic stroke.

FUNDING

Bayer AG.

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.

Rivaroxaban versus aspirin on functional and cognitive outcomes after embolic stroke of undetermined source: NAVIGATE ESUS trial

BACKGROUND

The effect of interventions on functional impairment is an important outcome in stroke prevention trials and should be considered as an adjunct to counting discrete events. In the NAVIGATE-ESUS trial, 7213 patients with recent embolic strokes of undetermined source were randomized to rivaroxaban (15 mg once daily) or aspirin (100 mg daily). After 11 months there was no effect on the prevention of recurrent stroke.

AIMS

To determine the effect of rivaroxaban compared to aspirin on functional and cognitive outcomes.

METHODS

Function and cognition were measured at baseline, 1 year, and study end using the Standard Assessment of Global Everyday Activities (SAGEA), a 15-item scale assessing cognitive, instrumental, and basic activities of daily living as well as mobility, and the Montreal Cognitive Assessment (MoCA). Changes in scores were calculated by subtracting either study end or 1-year scores from baseline, and differences in distributions were compared using the Mann-Whitney U test. SAGEA and MoCA scores were also correlated with recurrent stroke.

RESULTS

Follow-up SAGEA scores were available in 6378 (88%) participants. There was no difference in change in function for those allocated to rivaroxaban compared to aspirin (Mann-Whitney U test, p = 0.8), with both distributions having a median (25p,75p) change of 0 (-2,1). Overall, more of those who experienced a recurrent stroke (n=247; mostly minor ischemic), reported functional difficulty at study end versus entry, compared with those who did not (51% versus 30%, chi-square test, p< 0.001), and this was consistent across global regions. There was no difference in the change in cognition by treatment group, nor were recurrent strokes associated with a change in cognition.

CONCLUSIONS

Rivaroxaban, compared to aspirin, was not associated with changes in functional or cognitive status in patients with recent ESUS. The SAGEA scale detected changes in functional status associated with recurrent strokes in an international stroke population.

Evaluating Rates of Recurrent Ischemic Stroke Among Young Adults With Embolic Stroke of Undetermined Source: The Young ESUS Longitudinal Cohort Study

Importance

Cryptogenic strokes constitute approximately 40% of ischemic strokes in young adults, and most meet criteria for the embolic stroke of undetermined source (ESUS). Two randomized clinical trials, NAVIGATE ESUS and RESPECT ESUS, showed a high rate of stroke recurrence in older adults with ESUS but the prognosis and prognostic factors among younger individuals with ESUS is uncertain.

Objective

To determine rates of and factors associated with recurrent ischemic stroke and death and new-onset atrial fibrillation (AF) among young adults.

Design, Setting, and Participants

This multicenter longitudinal cohort study with enrollment from October 2017 to October 2019 and a mean follow-up period of 12 months ending in October 2020 included 41 stroke research centers in 13 countries. Consecutive patients 50 years and younger with a diagnosis of ESUS were included. Of 576 screened, 535 participants were enrolled after 1 withdrew consent, 41 were found to be ineligible, and 2 were excluded for other reasons. The final follow-up visit was completed by 520 patients.

Main Outcomes and Measures

Recurrent ischemic stroke and/or death, recurrent ischemic stroke, and prevalence of patent foramen ovale (PFO).

Results

The mean (SD) age of participants was 40.4 (7.3) years, and 297 (56%) participants were male. The most frequent vascular risk factors were tobacco use (240 patients [45%]), hypertension (118 patients [22%]), and dyslipidemia (109 patients [20%]). PFO was detected in 177 participants (50%) who had transthoracic echocardiograms with bubble studies. Following initial ESUS, 468 participants (88%) were receiving antiplatelet therapy, and 52 (10%) received anticoagulation. The recurrent ischemic stroke and death rate was 2.19 per 100 patient-years, and the ischemic stroke recurrence rate was 1.9 per 100 patient-years. Of the recurrent strokes, 9 (64%) were ESUS, 2 (14%) were cardioembolic, and 3 (21%) were of other determined cause. AF was detected in 15 participants (2.8%; 95% CI, 1.6-4.6). In multivariate analysis, the following were associated with recurrent ischemic stroke: history of stroke or transient ischemic attack (hazard ratio, 5.3; 95% CI, 1.8-15), presence of diabetes (hazard ratio, 4.4; 95% CI, 1.5-13), and history of coronary artery disease (hazard ratio, 10; 95% CI, 4.8-22).

Conclusions and Relevance

In this large cohort of young adult patients with ESUS, there was a relatively low rate of subsequent ischemic stroke and a low frequency of new-onset AF. Most recurrent strokes also met the criteria for ESUS, suggesting the need for future studies to improve our understanding of the underlying stroke mechanism in this population.

Oral anticoagulation versus antiplatelet therapy for secondary stroke prevention in patients with embolic stroke of undetermined source: A systematic review and meta-analysis

Purpose

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy and safety of direct oral anticoagulation (DOAC) compared with antiplatelet therapy for secondary stroke prevention in adult patients with embolic stroke of undetermined source (ESUS).

Method

We searched major databases (Embase, MEDLINE, CINAHL, CENTRAL, and Web of Science) for RCTs published until March 2021. The primary outcome was recurrent stroke, and the main safety outcomes were major bleeding and clinically relevant non-major bleeding (CRNB). We assessed risk of bias using the Cochrane Risk of Bias tool. We used a random-effects model to determine pooled risk ratios and 95% confidence intervals in the datasets and key subgroups.

Findings

Our search identified two RCTs, involving a total of 12,603 patients with ESUS. Anticoagulation with dabigatran or rivaroxaban compared with aspirin did not reduce the risk of recurrent stroke (RR, 0.96 [0.76–1.20]) or increase major bleeding (RR, 1.77 [0.80–3.89]) but significantly increased the composite of major or clinically relevant non-major bleeding (RR, 1.57 [1.26–1.97]). Prespecified subgroup analysis demonstrated consistent results according to age and sex. Additional post-hoc subgroup analyses demonstrated consistent results according to prior stroke and presence of a patent foramen ovale but suggested that DOACs reduced recurrent stroke in patients with an estimated glomerular filtration rate (eGFR) <50 and 50-80 ml/min but not in those with eGFR >80 ml/min (interaction P = 0.0234).

Discussion/conclusion

Direct oral anticoagulations are not more effective than aspirin in preventing stroke recurrence in patients with ESUS and increase bleeding.

Registration

PROSPERO ID: CRD42019138593

Functional Abilities of an International Post-Stroke Population: Standard Assessment of Global Everyday Activities (SAGEA) Scale

BACKGROUND AND OBJECTIVES

Function is an important outcome after stroke; traditional assessments may not capture functional deficits important to patients. We examined the validity of the Standard Assessment of Global Everyday Activities (SAGEA), a patient-reported outcome that assesses activities important to patients and for use in international clinical trials.

METHODS

The NAVIGATE-ESUS trial evaluated rivaroxaban compared to aspirin in preventing recurrent stroke in 7213 participants. The Modified Rankin Scale (mRS), the National Institutes of Health Stroke Scale (NIHSS), and the SAGEA were collected at entry. Chi square tests were used to compare proportions and Spearman rank correlations were used to compare between measures. SAGEA was compared to the Modified Frailty Index (MFI) and the occurrence of infarct to examine criterion validity RESULTS: Participants were 67 years, 2/3 were male, and at baseline 30% had no disability and 58% had slight disability according to mRS scores. SAGEA was weakly correlated with the mRS (r=0.37), the NIHSS (r=0.29) and the MFI (r=0.30). Of the 2154 with an mRS score of 0, 61% reported difficulty on the SAGEA. The largest discrepancies between SAGEA and other measures were because of cognitive functional deficits detected by the SAGEA that were not identified on other assessments. A larger number of MRI identified infarcts (acute and covert) were associated with a higher SAGEA score (p=0.007).

CONCLUSIONS

The SAGEA is a simple, globally applicable measure of cognitive and functional abilities that identifies issues that other commonly used assessments of disability and function do not capture.

Rivaroxaban versus aspirin for prevention of covert brain infarcts in patients with embolic stroke of undetermined source: NAVIGATE ESUS MRI substudy

Background

Covert brain infarcts are associated with important neurological morbidity. Their incidence in patients with embolic stroke of undetermined source (ESUS) is unknown.

Aims

To assess the incidence of covert brain infarcts and cerebral microbleeds using MRI in a prospective substudy of the NAVIGATE ESUS randomized trial and to evaluate the effects of antithrombotic therapies.

Methods

At 87 sites in 15 countries, substudy participants were randomly assigned to receive rivaroxaban 15 mg daily or aspirin 100 mg daily and underwent brain MRI near randomization and after study termination. The primary outcome was incident brain infarct (clinical ischemic stroke or covert brain infarct). Brain infarcts and microbleeds were ascertained centrally by readers unaware of treatment. Treatment effects were estimated using logistic regression.

Results

Among the 718 substudy participants with interpretable, paired MRIs, the mean age was 67 years and 61% were men with a median of 52 days between the qualifying ischemic stroke and randomization and a median of seven days between randomization and baseline MRI. During the median (IQR) 11 (12) month interval between scans, clinical ischemic strokes occurred in 27 (4%) participants, while 60 (9%) of the remaining participants had an incident covert brain infarct detected by MRI. Assignment to rivaroxaban was not associated with reduction in the incidence of brain infarct (OR 0.77, 95% CI 0.49, 1.2) or of covert brain infarct among those without clinical stroke (OR 0.85, 95% CI 0.50, 1.4). New microbleeds were observed in 7% and did not differ among those assigned rivaroxaban vs. aspirin (HR 0.95, 95% CI 0.52–1.7).

Conclusions

Incident covert brain infarcts occurred in twice as many ESUS patients as a clinical ischemic stroke. Treatment with rivaroxaban compared with aspirin did not significantly reduce the incidence of covert brain infarcts or increase the incidence of microbleeds, but the confidence intervals for treatment effects were wide.

Registration:https://www.clinicaltrials.gov. Unique identifier: NCT 02313909

Frequency and Patterns of Brain Infarction in Patients With Embolic Stroke of Undetermined Source: NAVIGATE ESUS Trial

BACKGROUND AND PURPOSE

The spectrum of brain infarction in patients with embolic stroke of undetermined source (ESUS) has not been well characterized. Our objective was to define the frequency and pattern of brain infarcts detected by magnetic resonance imaging (MRI) among patients with recent ESUS participating in a clinical trial.

METHODS

In the NAVIGATE ESUS trial (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source), an MRI substudy was carried out at 87 sites in 15 countries. Participants underwent an MRI using a specified protocol near randomization. Images were interpreted centrally by those unaware of clinical characteristics.

RESULTS

Among the 918 substudy cohort participants, the mean age was 67 years and 60% were men with a median (interquartile range) of 64 (26-115) days between the qualifying ischemic stroke and MRI. On MRI, 855 (93%) had recent or chronic brain infarcts that were multiple in 646 (70%) and involved multiple arterial territories in 62% (401/646). Multiple brain infarcts were present in 68% (510/755) of those without a history of stroke or transient ischemic attack before the qualifying ESUS. Prior stroke/transient ischemic attack (P<0.001), modified Rankin Scale score >0 (P<0.001), and current tobacco use (P=0.01) were associated with multiple infarcts. Topographically, large and/or cortical infarcts were present in 89% (757/855) of patients with infarcts, while in 11% (98/855) infarcts were exclusively small and subcortical. Among those with multiple large and/or cortical infarcts, 57% (251/437) had one or more involving a different vascular territory from the qualifying ESUS.

CONCLUSIONS

Most patients with ESUS, including those without prior clinical stroke or transient ischemic attack, had multiple large and/or cortical brain infarcts detected by MRI, reflecting a substantial burden of clinical stroke and covert brain infarction. Infarcts most frequently involved multiple vascular territories.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02313909.

Mortality Benefit of Rivaroxaban Plus Aspirin in Patients With Chronic Coronary or Peripheral Artery Disease

BACKGROUND

The combination of 2.5 mg rivaroxaban twice daily and 100 mg aspirin once daily compared with 100 mg aspirin once daily reduces major adverse cardiovascular (CV) events in patients with chronic coronary artery disease (CAD) or peripheral artery disease (PAD).

OBJECTIVES

The aim of this work was to report the effects of the combination on overall and cause-specific mortality.

METHODS

The COMPASS trial enrolled 27,395 patients of whom 18,278 were randomized to the combination (n = 9,152) or aspirin alone (n = 9,126). Deaths were adjudicated by a committee blinded to treatment allocation. Previously identified high-risk baseline features were polyvascular disease, chronic kidney disease, mild or moderate heart failure, and diabetes.

RESULTS

During a median of 23 months of follow-up (maximum 47 months), 313 patients (3.4%) allocated to the combination and 378 patients (4.1%) allocated to aspirin alone died (hazard ratio [HR]: 0.82; 95% confidence interval [CI]: 0.71-0.96; P = 0.01). Compared with aspirin, the combination reduced CV death (160 [1.7%] vs 203 [2.2%]; HR: 0.78; 95% CI: 0.64-0.96; P = 0.02) but not non-CV death. There were fewer deaths following MI, stroke, and CV procedures, as well as fewer sudden cardiac, other, and unknown causes of CV deaths and coronary heart disease deaths. Patients with 0, 1, 2, and 3 or 4 high-risk features at baseline had 4.2, 4.8, 25.0, and 53.9 fewer deaths, respectively, per 1000 patients treated for 30 months.

CONCLUSIONS

The combination of rivaroxaban and aspirin compared with aspirin reduced overall and CV mortality with consistent reductions in cause specific CV mortality in patients with chronic CAD or PAD. The absolute mortality benefits are greater with increasing baseline risk. (Cardiovascular Outcomes for People Using Anticoagulant Strategies [COMPASS]; NCT01776424).

Microbleeds and the Effect of Anticoagulation in Patients With Embolic Stroke of Undetermined Source: An Exploratory Analysis of the NAVIGATE ESUS Randomized Clinical Trial

Importance

The reported associations of cerebral microbleeds with recurrent stroke and intracerebral hemorrhage have raised concerns regarding antithrombotic treatment in patients with a history of stroke and microbleeds on magnetic resonance imaging.

Objective

To characterize microbleeds in embolic strokes of undetermined source (ESUS) and report interactions between microbleeds and the effects of random assignment to anticoagulant vs antiplatelet therapy.

Design, Setting, and Participants

Subgroup analyses of the New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial vs Aspirin to Prevent Embolism in ESUS (NAVIGATE ESUS) international, double-blind, randomized, event-driven phase 3 clinical trial. Participants were enrolled between December 2014 and September 2017 and followed up for a median of 11 months. The study setting included 459 stroke recruitment centers in 31 countries. Patients aged 50 years or older who had neuroimaging-confirmed ESUS between 7 days and 6 months before screening were eligible. Of these 7213 NAVIGATE ESUS participants, 3699 (51%) had information on cerebral microbleeds reported on their baseline clinical magnetic resonance imaging and were eligible for these analyses. Patients with a prior history of symptomatic intracerebral hemorrhage were excluded from the NAVIGATE ESUS trial.

Interventions

Rivaroxaban, 15 mg, compared with aspirin, 100 mg, daily.

Main Outcomes and Measures

The primary outcome was recurrent stroke. Secondary outcomes were ischemic stroke, intracerebral hemorrhage, and all-cause mortality.

Results

Microbleeds were present in 395 of 3699 participants (11%). Of patients with cerebral microbleeds, mean (SD) age was 69.5 (9.4) years, 241 were men (61%), and 201 were White (51%). Advancing age (odds ratio [OR] per year, 1.03; 95% CI, 1.01-1.04), East Asian race/ethnicity (OR, 1.57; 95% CI, 1.04-2.37), hypertension (OR, 2.20; 95% CI, 1.54-3.15), multiterritorial infarcts (OR, 1.95; 95% CI, 1.42-2.67), chronic infarcts (OR, 1.78; 95% CI, 1.42-2.23), and occult intracerebral hemorrhage (OR, 5.23; 95% CI, 2.76-9.90) were independently associated with microbleeds. The presence of microbleeds was associated with a 1.5-fold increased risk of recurrent stroke (hazard ratio [HR], 1.5; 95% CI, 1.0-2.3), a 4-fold risk of intracerebral hemorrhage (HR, 4.2; 95% CI, 1.3-13.9), a 2-fold risk of all-cause mortality (HR, 2.1; 95% CI, 1.1-4.3), and strictly lobar microbleeds with an approximately 2.5-fold risk of ischemic stroke (HR, 2.3; 95% CI, 1.3-4.3). There were no interactions between microbleeds and treatment assignments for recurrent stroke, ischemic stroke, or all-cause mortality. The HR of intracerebral hemorrhage on rivaroxaban was similar between persons with microbleeds (HR, 3.1; 95% CI, 0.3-30.0) and persons without microbleeds (HR, 3.0; 95% CI, 0.6-14.7; interaction P = .97).

Conclusions and Relevance

Microbleeds mark an increased risk of recurrent stroke, ischemic stroke, intracerebral hemorrhage, and mortality in ESUS but do not appear to influence effects of rivaroxaban on clinical outcomes.

Trial Registration

ClinicalTrials.gov Identifier: NCT02313909.

Characteristics of Recurrent Ischemic Stroke After Embolic Stroke of Undetermined Source: Secondary Analysis of a Randomized Clinical Trial

Importance

The concept of embolic stroke of undetermined source (ESUS) unifies a subgroup of cryptogenic strokes based on neuroimaging, a defined minimum set of diagnostic tests, and exclusion of certain causes. Despite an annual stroke recurrence rate of 5%, little is known about the etiology underlying recurrent stroke after ESUS.

Objective

To identify the stroke subtype of recurrent ischemic strokes after ESUS, to explore the interaction with treatment assignment in each category, and to examine the consistency of cerebral location of qualifying ESUS and recurrent ischemic stroke.

Design, Setting, and Participants

The NAVIGATE-ESUS trial was a randomized clinical trial conducted from December 23, 2014, to October 5, 2017. The trial compared the efficacy and safety of rivaroxaban and aspirin in patients with recent ESUS (n = 7213). Ischemic stroke was validated in 309 of the 7213 patients by adjudicators blinded to treatment assignment and classified by local investigators into the categories ESUS or non-ESUS (ie, cardioembolic, atherosclerotic, lacunar, other determined cause, or insufficient testing). Five patients with recurrent strokes that could not be defined as ischemic or hemorrhagic in absence of neuroimaging or autopsy were excluded. Data for this secondary post hoc analysis were analyzed from March to June 2019.

Interventions

Patients were randomly assigned to receive rivaroxaban, 15 mg/d, or aspirin, 100 mg/d.

Main Outcomes and Measures

Association of recurrent ESUS with stroke characteristics.

Results

A total of 309 patients (205 men [66%]; mean [SD] age, 68 [10] years) had ischemic stroke identified during the median follow-up of 11 (interquartile range [IQR], 12) months (annualized rate, 4.6%). Diagnostic testing was insufficient for etiological classification in 39 patients (13%). Of 270 classifiable ischemic strokes, 156 (58%) were ESUS and 114 (42%) were non-ESUS (37 [32%] cardioembolic, 26 [23%] atherosclerotic, 35 [31%] lacunar, and 16 [14%] other determined cause). Atrial fibrillation was found in 27 patients (9%) with recurrent ischemic stroke and was associated with higher morbidity (median change in modified Rankin scale score 2 [IQR, 3] vs 0 (IQR, 1]) and mortality (15% vs 1%) than other causes. Risk of recurrence did not differ significantly by subtype between treatment groups. For both the qualifying and recurrent strokes, location of infarct was more often in the left (46% and 54%, respectively) than right hemisphere (40% and 37%, respectively) or brainstem or cerebellum (14% and 9%, respectively).

Conclusions and Relevance

In this secondary analysis of randomized clinical trial data, most recurrent strokes after ESUS were embolic and of undetermined source. Recurrences associated with atrial fibrillation were a minority but were more often disabling and fatal. More extensive investigation to identify the embolic source is important toward an effective antithrombotic strategy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02313909.

Aspirin Use and Risk of Subdural Hematoma: Updated Meta-Analysis of Randomized Trials

BACKGROUND AND PURPOSE

Subdural hematomas are an uncommon, but a serious, bleeding complication of antithrombotic therapies. We update our previous inconclusive meta-analysis to better estimate the risk of subdural hematoma associated with aspirin use.

METHODS

For the initial meta-analysis, nine randomized trials published between1980 and 2012 comparing aspirin with placebo/control were considered. Additional data from four large primary prevention trials were added. Two reviewers independently extracted data on subdural hematomas, with differences resolved by joint review and consensus.

RESULTS

Numbers of subdural hematoma were available from thirteen randomized trials involving 155,554 participants comparing aspirin (dosage range 25 mg twice daily to 325 mg daily) to placebo (ten double-blind trials) or no aspirin (three trials). Participants included healthy healthcare providers, older people with vascular risk factors without manifest vascular disease, and those with atrial fibrillation or chronic angina. Pooling all trials, subdural hematomas were identified in 93 of 77,698 participants assigned to aspirin versus 62 of 77,856 participants assigned to placebo/no aspirin. By meta-analysis, the relative risk ratio_meta of subdural hematoma associated with assignment to aspirin was 1.5 (95%CI 1.1, 2.0, p = 0.01; p = 0.9 for heterogeneity, I² index = 0%). Based on recent primary prevention trials, subdural hematoma diagnosis averaged 1 per 3,125 people per year without aspirin use; the absolute increase associated with aspirin use was estimated as one additional subdural hematoma per 6,500 patients annually.

CONCLUSIONS

This meta-analysis confirms that aspirin use increases the relative risk of subdural hematoma, but the absolute increased rate associated with aspirin therapy is very low for most people.

Antihypertensives and Statin Therapy for Primary Stroke Prevention: A Secondary Analysis of the HOPE-3 Trial

[Figure: see text].

Stroke Prevention in Atrial Fibrillation

Ischemic strokes related to atrial fibrillation are highly prevalent, presenting with severe neurologic syndromes and associated with high risk of recurrence. Although advances have been made in both primary and secondary stroke prevention for patients with atrial fibrillation, the long-term risks for stroke recurrence and bleeding complications from antithrombotic treatment remain substantial. We summarize the major advances in stroke prevention for patients with atrial fibrillation during the past 30 years and focus on novel diagnostic and treatment approaches currently under investigation in ongoing clinical trials. Non–vitamin K antagonist oral anticoagulants have been proven to be safer and equally effective compared with warfarin in stroke prevention for patients with nonvalvular atrial fibrillation. Non–vitamin K antagonist oral anticoagulants are being investigated for the treatment of patients with atrial fibrillation and rheumatic heart disease, for the treatment of patients with recent embolic stroke of undetermined source and indirect evidence of cardiac embolism, and in the prevention of vascular-mediated cognitive decline in patients with atrial fibrillation. Multiple clinical trials are assessing the optimal timing of non–vitamin K antagonist oral anticoagulant initiation after a recent ischemic stroke and the benefit:harm ratio of non–vitamin K antagonist oral anticoagulant treatment in patients with atrial fibrillation and history of previous intracranial bleeding. Ongoing trials are addressing the usefulness of left atrial appendage occlusion in both primary and secondary stroke prevention for patients with atrial fibrillation, including those with high risk of bleeding. The additive value of prolonged cardiac monitoring for subclinical atrial fibrillation detection through smartphone applications or implantable cardiac devices, together with the optimal medical management of individuals with covert paroxysmal atrial fibrillation, is a topic of intensive research interest. Colchicine treatment and factor XIa inhibition constitute 2 novel pharmacologic approaches that might provide future treatment options in the secondary prevention of cardioembolic stroke attributable to atrial fibrillation.

Association Between Low-Dose Rivaroxaban With or Without Aspirin and Ischemic Stroke Subtypes: A Secondary Analysis of the COMPASS Trial

Importance

The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) randomized clinical trial was stopped early owing to the efficacy of low-dose rivaroxaban plus aspirin in preventing major cardiovascular events. The main reason for early trial termination was the effect of combination therapy on reducing ischemic strokes.

Objective

To analyze the association between low-dose rivaroxaban with or without aspirin and different ischemic stroke subtypes.

Design, Setting, and Participants

This is a secondary analysis of a multicenter, double-blind, randomized, placebo-controlled study that was performed in 33 countries from March 12, 2013, to May 10, 2016. Patients with stable atherosclerotic vascular disease were eligible, and a total of 27 395 participants were randomized and followed up to February 6, 2017. All first ischemic strokes and uncertain strokes that occurred by this date were adjudicated using TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria. The analysis of ischemic stroke subtypes was evaluated using an intention-to-treat principle. Statistical analysis was performed from March 12, 2013, to February 6, 2017.

Interventions

Participants received rivaroxaban (2.5 mg twice a day) plus aspirin (100 mg once a day), rivaroxaban (5 mg twice a day), or aspirin (100 mg once a day).

Main Outcomes and Measures

Risk of ischemic stroke subtypes during follow-up.

Results

A total of 291 patients (66 women; mean [SD] age, 69.4 [8.5] years; 43 [14.8%] had a previous nonlacunar stroke) experienced an ischemic stroke. During the study, 49 patients (16.8%) received a diagnosis of atrial fibrillation. Applying TOAST criteria, 59 strokes (20.3%) were cardioembolic, 54 strokes (18.6%) were secondary to greater than 50% stenosis of the ipsilateral internal carotid artery, 42 strokes (14.4%) had a negative evaluation that met criteria for embolic stroke of undetermined source, and 21 strokes (7.2%) were secondary to small vessel disease. There were significantly fewer cardioembolic strokes (hazard ratio [HR], 0.40 [95% CI, 0.20-0.78]; P = .005) and embolic strokes of undetermined source (HR, 0.30 [95% CI, 0.12-0.74]; P = .006) in the combination therapy group compared with the aspirin-only group. A trend for reduction in strokes secondary to small vessel disease (HR, 0.36 [95% CI, 0.12-1.14]; P = .07) was not statistically significant. No significant difference was observed between the 2 groups in strokes secondary to greater than 50% carotid artery stenosis (HR, 0.85 [95% CI, 0.45-1.60]; P = .61). Rivaroxaban, 5 mg, twice daily showed a trend for reducing cardioembolic strokes compared with aspirin (HR, 0.57 [95% CI, 0.31-1.03]; P = .06) but was not associated with reducing other stroke subtypes.

Conclusions and Relevance

For patients with systemic atherosclerosis, low-dose rivaroxaban plus aspirin was associated with large, significant reductions in cardioembolic strokes and embolic strokes of undetermined source. However, these results of exploratory analysis need to be independently confirmed before influencing clinical practice.

Trial Registration

ClinicalTrials.gov identifier: NCT01776424.

Rivaroxaban for Prevention of Covert Brain Infarcts and Cognitive Decline

Background and Purpose:

Covert brain infarcts are associated with cognitive decline. It is not known whether therapies that prevent symptomatic stroke prevent covert infarcts. COMPASS compared rivaroxaban with and without aspirin with aspirin for the prevention of stroke, myocardial infarction, and vascular death in participants with stable vascular disease and was terminated early because of benefits of rivaroxaban 2.5 mg twice daily plus aspirin over aspirin. We obtained serial magnetic resonance imagings and cognitive tests in a consenting subgroup of COMPASS patients to examine treatment effects on infarcts, cerebral microbleeds, and white matter hyperintensities.

Methods:

Baseline and follow-up magnetic resonance imagings were completed in 1445 participants with a mean (SD) interval of 2.0 (0.7) years. Whole-brain T1, T2 fluid-attenuated inversion recovery, T2* sequences were centrally interpreted by blinded, trained readers. Participants had serial measurements of cognition and function. The primary end point was the proportion of participants with incident covert infarcts. Secondary end points were the composite of clinical stroke and covert brain infarcts, cerebral microbleeds, and white matter hyperintensities.

Results:

At baseline, 493 (34.1%) participants had infarcts. Incident covert infarcts occurred in 55 (3.8%) participants. In the overall trial rivaroxaban plus aspirin reduced ischemic stroke by 49% (0.7% versus 1.4%; hazard ratio [95% CI], 0.51 [0.38–0.68]). In the magnetic resonance imaging substudy the effects of rivaroxaban+aspirin versus aspirin were: covert infarcts: 2.7% versus 3.5% (odds ratio [95% CI], 0.77 [0.37–1.60]); Covert infarcts or ischemic stroke: 2.9% versus 5.3% (odds ratio [95% CI], 0.53 [0.27–1.03]). Incident microbleeds occurred in 6.6% of participants and 65.7% of participants had an increase in white matter hyperintensities volume with no effect of treatment for either end point. There was no effect on cognitive tests.

Conclusions:

Covert infarcts were not significantly reduced by treatment with rivaroxaban and aspirin but estimates for the combination of ischemic stroke and covert infarcts were consistent with the effect on ischemic stroke in the overall trial.

Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01776424.

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.

Oral factor Xa inhibitors and risk of subdural hematoma

Objective

Subdural hematomas (SDHs) are an uncommon, but important, complication of anticoagulation therapy. We hypothesized that the risks of SDH would be similar during treatment with oral factor Xa inhibitors compared with aspirin.

Methods

We assessed the frequency and the effects of antithrombotic treatments on SDHs in the recent international Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) randomized trial comparing aspirin 100 mg daily, rivaroxaban 5 mg twice daily, and rivaroxaban 2.5 mg twice daily plus aspirin. A systematic review/meta-analysis of randomized trials comparing oral factor Xa inhibitors vs aspirin on SDH risk was undertaken.

Results

Among 27,395 COMPASS participants, 28 patients with SDHs were identified (mean age 72 years). SDH-associated mortality was 7%. Incidence was 0.06 per 100 patient-years (11 SDH/17,492 years observation) during the mean 23-month follow-up among aspirin-assigned patients and did not differ significantly between treatments. Three additional randomized controlled trials including 16,177 participants reported a total of 14 SDHs with an incidence ranging from 0.06 to 0.1 per 100 patient-years. Factor Xa inhibitor use was not associated with an increased risk of SDH compared to aspirin (odds ratio, 0.97; 95% confidence interval, 0.52–1.81; I2 = 0%).

Conclusion

The frequency of SDH was similar in all 3 treatment arms of the COMPASS trial. The COMPASS trial results markedly increase the available evidence from randomized comparisons of oral factor Xa inhibitors with aspirin regarding SDH. From available, albeit limited, evidence from 4 randomized trials, therapeutic dosages of factor Xa inhibitors do not appear to increase the risk of SDH compared with aspirin.

Clinical trial identifier number:

NCT01776424.

Recurrent Stroke With Rivaroxaban Compared With Aspirin According to Predictors of Atrial Fibrillation: Secondary Analysis of the NAVIGATE ESUS Randomized Clinical Trial

Importance

The NAVIGATE ESUS randomized clinical trial found that 15 mg of rivaroxaban per day does not reduce stroke compared with aspirin in patients with embolic stroke of undetermined source (ESUS); however, it substantially reduces stroke risk in patients with atrial fibrillation (AF).

Objective

To analyze whether rivaroxaban is associated with a reduction of recurrent stroke among patients with ESUS who have an increased risk of AF.

Design, Setting, and Participants

Participants were stratified by predictors of AF, including left atrial diameter, frequency of premature atrial contractions, and HAVOC score, a validated scheme using clinical features. Treatment interactions with these predictors were assessed. Participants were enrolled between December 2014 and September 2017, and analysis began March 2018.

Intervention

Rivaroxaban treatment vs aspirin.

Main Outcomes and Measures

Risk of ischemic stroke.

Results

Among 7112 patients with a mean (SD) age of 67 (9.8) years, the mean (SD) HAVOC score was 2.6 (1.8), the mean (SD) left atrial diameter was 3.8 (1.4) cm (n = 4022), and the median (interquartile range) daily frequency of premature atrial contractions was 48 (13-222). Detection of AF during follow-up increased for each tertile of HAVOC score: 2.3% (score, 0-2), 3.0% (score, 3), and 5.8% (score, >3); however, neither tertiles of the HAVOC score nor premature atrial contractions frequency impacted the association of rivaroxaban with recurrent ischemic stroke (P for interaction = .67 and .96, respectively). Atrial fibrillation annual incidence increased for each tertile of left atrial diameter (2.0%, 3.6%, and 5.2%) and for each tertile of premature atrial contractions frequency (1.3%, 2.9%, and 7.0%). Among the predefined subgroup of patients with a left atrial diameter of more than 4.6 cm (9% of overall population), the risk of ischemic stroke was lower among the rivaroxaban group (1.7% per year) compared with the aspirin group (6.5% per year) (hazard ratio, 0.26; 95% CI, 0.07-0.94; P for interaction = .02).

Conclusions and Relevance

The HAVOC score, left atrial diameter, and premature atrial contraction frequency predicted subsequent clinical AF. Rivaroxaban was associated with a reduced risk of recurrent stroke among patients with ESUS and moderate or severe left atrial enlargement; however, this needs to be independently confirmed before influencing clinical practice.

Frequency and Predictors of Major Bleeding in Patients With Embolic Strokes of Undetermined Source: NAVIGATE-ESUS Trial

BACKGROUND AND PURPOSE

Risks, sites, and predictors of major bleeding during antithrombotic therapies have not been well defined for patients with recent embolic stroke of undetermined source.

METHODS

Exploratory analysis of major bleeds defined by International Society of Thrombosis and Hemostasis criteria occurring among 7213 participants in international NAVIGATE (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial) embolic stroke of undetermined source randomized trial comparing rivaroxaban 15 mg daily with aspirin 100 mg daily.

RESULTS

During a median follow-up of 11 months, 85 major bleeds occurred. The most frequent site was gastrointestinal (38%), followed by intracranial (29%). Assignment to rivaroxaban (hazard ratio [HR], 2.7 [95% CI, 1.7-4.3]), East Asia region (HR, 2.5 [95% CI, 1.6-3.9]), systolic blood pressure ≥160 mm Hg (HR, 2.2 [95% CI, 1.2-3.8]), and reduced estimated glomerular filtration rate (HR, 1.2 per 10 mL/min per 1.73 m² decrease, [95% CI, 1.0-1.3]) were independently associated with presence of major bleeds. Five (6%) were fatal. Among 15 patients with intracerebral hemorrhage, 2 (13%) were fatal. There was no evidence of an early high-risk period following initiation of rivaroxaban. The annualized rate of intracerebral hemorrhage was 6-fold higher among East Asian participants (0.67%) versus all other regions (0.11%; HR, 6.3 [95% CI, 2.2-18.0]). Distribution of bleeding sites was similar for rivaroxaban and aspirin.

CONCLUSIONS

Among embolic stroke of undetermined source patients participating in an international randomized trial, independent predictors of major bleeding were assignment to rivaroxaban, East Asia region, increased systolic blood pressure, and impaired renal function. East Asia as a region was strongly associated with risk of intracerebral hemorrhage. Estimated glomerular filtration rate should be a consideration for stratifying bleeding risk. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02313909.

Potential Embolic Sources and Outcomes in Embolic Stroke of Undetermined Source in the NAVIGATE-ESUS Trial

Background and Purpose—

Emboli in embolic stroke of undetermined source (ESUS) may originate from various potential embolic sources (PES), some of which may respond better to anticoagulation, whereas others to antiplatelets. We analyzed whether rivaroxaban is associated with reduction of recurrent stroke compared with aspirin in patients with ESUS across different PES and by number of PES.

Methods—

We assessed the presence/absence of each PES (atrial cardiopathy, atrial fibrillation, arterial atherosclerosis, left ventricular dysfunction, cardiac valvulopathy, patent foramen ovale, cancer) in NAVIGATE-ESUS (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source) participants. Prevalence of each PES, as well as treatment effect and risk of event for each PES were determined. Results by number of PES were also determined. The outcomes were ischemic stroke, all-cause mortality, cardiovascular mortality, and myocardial infarction.

Results—

In 7213 patients (38% women, mean age 67years) followed for a median of 11 months, the 3 most prevalent PES were atrial cardiopathy (37%), left ventricular disease (36%), and arterial atherosclerosis (29%). Forty-one percent of all patients had multiple PES, with 15% having ≥3 PES. None or a single PES was present in 23% and 36%, respectively. Recurrent ischemic stroke risk was similar for rivaroxaban- and aspirin-assigned patients for each PES, except for those with cardiac valvular disease which was marginally higher in rivaroxaban-assigned patients (hazard ratio, 1.8 [95% CI, 1.0–3.0]). All-cause mortality risks were similar across treatment groups for each PES while too few myocardial infarctions and cardiovascular deaths occurred for meaningful assessment. Increasing number of PES was not associated with increased stroke recurrence nor all-cause mortality, and outcomes did not vary between rivaroxaban- and aspirin-assigned patients by number of PES.

Conclusions—

A large proportion of patients with ESUS had multiple PES which could explain the neutral results of NAVIGATE-ESUS. Recurrence rates between rivaroxaban- and aspirin-assigned patients were similar across the spectrum of PES.

Registration—

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02313909.

Rivaroxaban versus aspirin for secondary prevention of ischaemic stroke in patients with cancer: a subgroup analysis of the NAVIGATE ESUS randomized trial

BACKGROUND AND PURPOSE

Cancer is a frequent finding in ischaemic stroke patients. The frequency of cancer amongst participants in the NAVIGATE ESUS randomized trial and the distribution of outcome events during treatment with aspirin and rivaroxaban were investigated.

METHODS

Trial participation required a recent embolic stroke of undetermined source. Patients' history of cancer was recorded at the time of study entry. During a mean follow-up of 11 months, the effects of aspirin and rivaroxaban treatment on recurrent ischaemic stroke, major bleeding and all-cause mortality were compared between patients with cancer and patients without cancer.

RESULTS

Amongst 7213 randomized patients, 543 (7.5%) had cancer. Of all patients, 3609 were randomized to rivaroxaban [254 (7.0%) with cancer] and 3604 patients to aspirin [289 (8.0%) with cancer]. The annual rate of recurrent ischaemic stroke was 4.5% in non-cancer patients in the rivaroxaban arm and 4.6% in the aspirin arm [hazard ratio (HR) 0.98, 95% confidence interval (CI) 0.78-1.24]. In cancer patients, the rate of recurrent ischaemic stroke was 7.7% in the rivaroxaban arm and 5.4% in the aspirin arm (HR 1.43, 95% CI 0.71-2.87). Amongst cancer patients, the annual rate of major bleeds was non-significantly higher for rivaroxaban than aspirin (2.9% vs. 1.1%; HR 2.57, 95% CI 0.67-9.96; P for interaction 0.95). All-cause mortality was similar in both groups.

CONCLUSIONS

Our exploratory analyses show that patients with embolic stroke of undetermined source and a history of cancer had similar rates of recurrent ischaemic strokes and all-cause mortality during aspirin and rivaroxaban treatments and that aspirin appeared safer than rivaroxaban in cancer patients regarding major bleeds. www.clinicaltrials.gov (NCT02313909).

Are large simple trials for dementia prevention possible?

New trials of dementia prevention are needed to test novel strategies and agents. Large, simple, cardiovascular trials have successfully discovered treatments with moderate but worthwhile effects to prevent heart attack and stroke. The design of these trials may hold lessons for the dementia prevention.

Here we outline suitable populations, interventions and outcomes for large simple trials in dementia prevention. We consider what features are needed to maximise efficiency. Populations could be selected by age, clinical or genetic risk factors or clinical presentation. Patients and their families prioritise functional and clinical outcomes over cognitive scores and levels of biomarkers. Loss of particular functions or dementia diagnoses therefore are most meaningful to participants and potential patients and can be measured in large trials.

The size of the population and duration of follow-up needed for dementia prevention trials will be a major challenge and will need collaboration between many clinical investigators, funders and patient organisations.

Dabigatran Treatment of Acute Noncardioembolic Ischemic Stroke

Background and Purpose- Patients with transient ischemic attack (TIA) and minor ischemic stroke are at risk for early recurrent cerebral ischemia. Anticoagulants are associated with reduced recurrence but also increased hemorrhagic transformation (HT). The safety of the novel oral anticoagulant dabigatran in acute stroke has not been evaluated. Methods- DATAS II (Dabigatran Treatment of Acute Stroke II) was a phase II prospective, randomized open label, blinded end point trial. Patients with noncardioembolic stroke/transient ischemic attack (National Institutes of Health Stroke Scale score, ≤9; infarct volume, ≤25 mL) were randomized to dabigatran or aspirin. Magnetic resonance imaging was performed before randomization and repeated at day 30. Imaging end points were ascertained centrally by readers blinded to treatment. The primary end point was symptomatic HT within 37 days of randomization. Results- A total of 305 patients, mean age 66.59±13.21 years, were randomized to dabigatran or aspirin a mean of 42.00±17.31 hours after symptom onset. The qualifying event was a transient ischemic attack in 21%, and ischemic stroke in 79% of patients. Median National Institutes of Health Stroke Scale (interquartile range) was 1 (0-2), and mean infarct volume 3.2±6.5 mL. No symptomatic HT occurred. Asymptomatic petechial HT developed in 11/142 (7.8%) of dabigatran-assigned patients and 5/142 (3.5%) of aspirin-assigned patients (relative risk, 2.301 [95% CI, 0.778-6.802]). Baseline infarct volume predicted incident HT (odds ratio, 1.07 [95% CI, 1.03-1.12]; P=0.0026). Incident covert infarcts on day 30 imaging occurred in 9/142 (6.3%) of dabigatran-assigned and 14/142 (9.8%) of aspirin-assigned patients (relative risk, 0.62 [95% CI, 0.26, 1.48]). Conclusions- Dabigatran was associated with a risk of HT similar to aspirin in acute minor noncardioembolic ischemic stroke/transient ischemic attack. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02295826.

Atrial Fibrillation and Cognitive Function: JACC Review Topic of the Week

Numerous vascular risk factors and vascular diseases contribute to cognitive impairment and dementia. Many studies and registries show an association of atrial fibrillation (AF) with cognitive impairment, cognitive decline, and dementia. This is true for vascular dementia and Alzheimer's disease. The assumed multifactorial mechanisms include ischemic stroke, both apparent and silent, cerebral microinfarcts, cerebral hemorrhage, and reduced cerebral blood flow. A number of retrospective observational and prospective studies support that anticoagulation in patients with AF may reduce the risk of cognitive decline and dementia. This holds for both vitamin K antagonists (e.g., warfarin) and direct oral anticoagulants. However, it still remains unproven if anticoagulation reduces cognitive decline and dementia in AF patients based on randomized trials.

Atrial Cardiopathy and Nonstenosing Large Artery Plaque in Patients With Embolic Stroke of Undetermined Source

Background and Purpose- Atrial cardiopathy and atherosclerotic plaque are two potential mechanisms underlying embolic strokes of undetermined source (ESUS). The relationship between these two mechanisms among ESUS patients remains unclear. A better understanding of their association may inform targeted secondary prevention strategies. Methods- We examined the association between atrial cardiopathy and atherosclerotic plaque in the NAVIGATE ESUS trial (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source), which enrolled 7213 patients with recent ESUS during 2014 to 2017. For this analysis, we included patients with data on left atrial dimension, location of brain infarction, and cervical large artery plaque. The variables of primary interest were left atrial diameter and cervical plaque ipsilateral to brain infarction. Secondary markers of atrial cardiopathy were premature atrial contractions on Holter monitoring and newly diagnosed atrial fibrillation. For descriptive purposes, left atrial enlargement was defined as ≥4.7 cm. Multivariable logistic regression was used to examine the association between atrial cardiopathy markers and ipsilateral plaque after adjustment for age, sex, body mass index, hypertension, diabetes mellitus, current smoking, and hyperlipidemia. Results- Among 3983 eligible patients, 235 (5.9%) had left atrial enlargement, 939 (23.6%) had ipsilateral plaque, and 94 (2.4%) had both. Shared risk factors for left atrial enlargement and ipsilateral plaque were male sex, white race, hypertension, tobacco use, and coronary artery disease. Despite shared risk factors, increasing left atrial dimension was not associated with ipsilateral plaque after adjustment for covariates (odds ratio per cm, 1.1 [95% CI, 1.0-1.2]; P=0.08). We found no consistent associations between secondary markers of atrial cardiopathy and ipsilateral plaque. Conclusions- In a large population of patients with ESUS, we did not observe a notable association between atrial cardiopathy and atherosclerotic plaque, and few patients had both conditions. These findings suggest that atrial cardiopathy and atherosclerotic plaque may be distinct, nonoverlapping risk factors for stroke among ESUS patients.

Stroke Outcomes in the COMPASS Trial

BACKGROUND

Strokes were significantly reduced by the combination of rivaroxaban plus aspirin in comparison with aspirin in the COMPASS trial (Cardiovascular Outcomes for People Using Anticoagulation Strategies). We present detailed analyses of stroke by type, predictors, and antithrombotic effects in key subgroups.

METHODS

Participants had stable coronary artery or peripheral artery disease and were randomly assigned to receive aspirin 100 mg once daily (n=9126), rivaroxaban 5 mg twice daily (n=9117), or rivaroxaban 2.5 mg twice daily plus aspirin (n=9152). Patients who required anticoagulation or had a stroke within 1 month, previous lacunar stroke, or intracerebral hemorrhage were excluded.

RESULTS

During a mean follow-up of 23 months, fewer patients had strokes in the rivaroxaban plus aspirin group than in the aspirin group (83 [0.9% per year] versus 142 [1.6% per year]; hazard ratio [HR], 0.58; 95% CI, 0.44-0.76; P<0.0001). Ischemic/uncertain strokes were reduced by nearly half (68 [0.7% per year] versus 132 [1.4% per year]; HR, 0.51; 95% CI, 0.38-0.68; P<0.0001) by the combination in comparison with aspirin. No significant difference was noted in the occurrence of stroke in the rivaroxaban alone group in comparison with aspirin: annualized rate of 0.7% (HR, 0.82; 95% CI, 0.65-1.05). The occurrence of fatal and disabling stroke (modified Rankin Scale, 3-6) was decreased by the combination (32 [0.3% per year] versus 55 [0.6% per year]; HR, 0.58; 95% CI, 0.37-0.89; P=0.01). Independent predictors of stroke were prior stroke, hypertension, systolic blood pressure at baseline, age, diabetes mellitus, and Asian ethnicity. Prior stroke was the strongest predictor of incident stroke (HR, 3.63; 95% CI, 2.65-4.97; P<0.0001) and was associated with a 3.4% per year rate of stroke recurrence on aspirin. The effect of the combination in comparison with aspirin was consistent across subgroups with high stroke risk, including those with prior stroke.

CONCLUSIONS

Low-dose rivaroxaban plus aspirin is an important new antithrombotic option for primary and secondary stroke prevention in patients with clinical atherosclerosis.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01776424.

Regional, sex, and age differences in diagnostic testing among participants in the NAVIGATE-ESUS trial

BACKGROUND AND AIM

The diagnosis of embolic stroke of undetermined source (ESUS) is based on excluding other more likely stroke etiologies, and therefore diagnostic testing plays an especially crucial role. Our objective was to compare the diagnostic testing by region, sex, and age among the participants of NAVIGATE-ESUS trial.

METHODS

Participants were grouped according to five global regions (North America, Latin America, Western Europe, Eastern Europe and East Asia), age (<60, 60-74, and >75 years), and sex. Frequencies of each diagnostic test within areas of echocardiography, cardiac rhythm monitoring, and arterial imaging were described and compared across groups. A multivariable logistic regression model for each diagnostic test was fit to assess the independent influence of each of region, age, and sex and likelihood of testing.

RESULTS

We included 6985 patients in the analysis (918 from North America; 746 from Latin America; 2853 from Western Europe; 1118 from Eastern Europe; 1350 from East Asia). Average age (highest in Western Europe (69 years), lowest in Eastern Europe (65 years)), % females (highest in Latin America (44%) and lowest in East Asia (31%)), and use of each diagnostic test varied significantly across regions. Region, but not sex, was independently associated with use of each diagnostic test examined. Transesophageal echocardiography and either CT or MR angiogram were more often used in younger patients.

CONCLUSION

Diagnostic testing differed by region, and less frequently by age, but not by sex. Our findings reflect the existing variations in global practice in diagnostic testing in ESUS patients.

Aortic Arch Atherosclerosis in Patients With Embolic Stroke of Undetermined Source: An Exploratory Analysis of the NAVIGATE ESUS Trial

Background and Purpose- Aortic arch atherosclerosis (AAA) is a possible source of embolism in patients with embolic stroke of undetermined source. Previous studies reported high rates of embolic events in patients with AAA, especially those with high-risk AAA. This exploratory analysis of NAVIGATE ESUS (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism in Embolic Stroke of Undetermined Source) focused on patients with AAA and assessed their characteristics, stroke recurrence rates, and response to treatment. Methods- The detection of AAA and the assessment of its features were based on transesophageal echocardiography that was done in 19% of participants. AAA plaques were considered to have complex features when reported as complex or ulcerated or were ≥4 mm in thickness or had a mobile thrombus present. Results- Among 1382 participants who had transesophageal echocardiography, 397 (29%) had AAA and 112 (8%) had complex AAA. Mean (SD) age (63 [10] versus 67 [9] versus 69 [9]; P<0.001), prevalence of diabetes mellitus (19% versus 26%, versus 32%; P=0.002), and aortic valvulopathy (10 versus 20 versus 20; P<0.001) increased across no versus noncomplex versus complex AAA, respectively. In multivariable analyses, increasing age, diabetes mellitus, aortic valvulopathy, statin use before randomization, chronic infarcts on imaging, and region were independently associated with any AAA versus no AAA and also with complex AAA versus no AAA. Multiterritorial qualifying infarcts rather than single-territory infarcts were observed in 21% with complex AAA versus 17% noncomplex versus 13% no AAA (P=0.07). Annualized rates of ischemic stroke recurrence were 7.2% versus 4.2% versus 5.6% for complex versus noncomplex versus no AAA, respectively. While prevalence of complex AAA increased with increasing risk score, after adjusting for risk score, we did not observe increased risk of recurrent stroke for patients with complex AAA (hazard ratio, 1.1; 95% CI, 0.53-2.4), although the number of outcomes was limited. In patients with complex AAA, 4 strokes occurred among rivaroxaban-assigned patients and 4 strokes among aspirin-assigned patients. Conclusions- Complex AAA is prevalent in embolic stroke of undetermined source patients and is associated with atherosclerotic burden. Whether complex AAA independently increases recurrent stroke risk and whether a non-vitamin-K oral anticoagulant as compared with aspirin may be effective for reducing recurrent stroke requires additional study. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT02313909.

Safety of Proton Pump Inhibitors Based on a Large, Multi-Year, Randomized Trial of Patients Receiving Rivaroxaban or Aspirin

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) are effective at treating acid-related disorders. These drugs are well tolerated in the short term, but long-term treatment was associated with adverse events in observational studies. We aimed to confirm these findings in an adequately powered randomized trial.

METHODS

We performed a 3 × 2 partial factorial double-blind trial of 17,598 participants with stable cardiovascular disease and peripheral artery disease randomly assigned to groups given pantoprazole (40 mg daily, n = 8791) or placebo (n = 8807). Participants were also randomly assigned to groups that received rivaroxaban (2.5 mg twice daily) with aspirin (100 mg once daily), rivaroxaban (5 mg twice daily), or aspirin (100 mg) alone. We collected data on development of pneumonia, Clostridium difficile infection, other enteric infections, fractures, gastric atrophy, chronic kidney disease, diabetes, chronic obstructive lung disease, dementia, cardiovascular disease, cancer, hospitalizations, and all-cause mortality every 6 months. Patients were followed up for a median of 3.01 years, with 53,152 patient-years of follow-up.

RESULTS

There was no statistically significant difference between the pantoprazole and placebo groups in safety events except for enteric infections (1.4% vs 1.0% in the placebo group; odds ratio, 1.33; 95% confidence interval, 1.01-1.75). For all other safety outcomes, proportions were similar between groups except for C difficile infection, which was approximately twice as common in the pantoprazole vs the placebo group, although there were only 13 events, so this difference was not statistically significant.

CONCLUSIONS

In a large placebo-controlled randomized trial, we found that pantoprazole is not associated with any adverse event when used for 3 years, with the possible exception of an increased risk of enteric infections. ClinicalTrials.gov Number: NCT01776424.

Efficacy and Safety of Rivaroxaban Versus Aspirin in Embolic Stroke of Undetermined Source and Carotid Atherosclerosis

Background and Purpose—

The sources of emboli in patients with embolic stroke of undetermined source (ESUS) are multiple and may not respond uniformly to anticoagulation. In this exploratory subgroup analysis of patients with carotid atherosclerosis in the NAVIGATE (New Approach Rivaroxaban Inhibition of Factor Xa in a Global Trial Versus ASA to Prevent Embolism)-ESUS trial, we assessed whether the treatment effect in this subgroup is consistent with the overall trial population and investigated the association of carotid atherosclerosis with recurrent ischemic stroke.

Methods—

Carotid atherosclerosis was analyzed either as the presence of mild (ie, 20%–49%) atherosclerotic stenosis or, separately, as the presence of carotid plaque. Primary efficacy outcome was ischemic stroke recurrence. Safety outcomes were major bleeding and symptomatic intracerebral bleeding.

Results—

Carotid plaque was present in 40% of participants and mild carotid stenosis in 11%. There was no significant difference in ischemic stroke recurrence between rivaroxaban- and aspirin-treated patients among 490 patients with carotid stenosis (5.0 versus 5.9/100 patient-years, respectively, hazard ratio [HR], 0.85; 95% CI, 0.39–1.87; P for interaction of treatment effect with patients without carotid stenosis 0.78) and among 2905 patients with carotid plaques (5.9 versus 4.9/100 patient-years, respectively, HR, 1.20; 95% CI, 0.86–1.68; P for interaction of treatment effect with patients without carotid stenosis 0.2). Among patients with carotid plaque, major bleeding was more frequent in rivaroxaban-treated patients compared with aspirin-treated (2.0 versus 0.5/100 patient-years, HR, 3.75; 95% CI, 1.63–8.65). Patients with carotid stenosis had similar rate of ischemic stroke recurrence compared with those without (5.4 versus 4.9/100 patient-years, respectively, HR, 1.11; 95% CI, 0.73–1.69), but there was a strong trend of higher rate of ischemic stroke recurrence in patients with carotid plaque compared with those without (5.4 versus 4.3/100 patient-years, respectively, HR, 1.23; 95% CI, 0.99–1.54).

Conclusions—

In ESUS patients with carotid atherosclerosis, we found no difference in efficacy between rivaroxaban and aspirin for prevention of recurrent stroke, but aspirin was safer, consistent with the overall trial results. Carotid plaque was much more often present ipsilateral to the qualifying ischemic stroke than contralateral, supporting an important etiological role of nonstenotic carotid disease in ESUS.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02313909.

Pantoprazole to Prevent Gastroduodenal Events in Patients Receiving Rivaroxaban and/or Aspirin in a Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND & AIMS

Antiplatelets and anticoagulants are associated with increased upper gastrointestinal bleeding. We evaluated whether proton pump inhibitor therapy could reduce this risk.

METHODS

We performed a 3 × 2 partial factorial double-blind trial of 17,598 participants with stable cardiovascular disease and peripheral artery disease. Participants were randomly assigned to groups given pantoprazole 40 mg daily or placebo, as well as rivaroxaban 2.5 mg twice daily with aspirin 100 mg once daily, rivaroxaban 5 mg twice daily, or aspirin 100 mg alone. The primary outcome was time to first upper gastrointestinal event, defined as a composite of overt bleeding, upper gastrointestinal bleeding from a gastroduodenal lesion or of unknown origin, occult bleeding, symptomatic gastroduodenal ulcer or ≥5 erosions, upper gastrointestinal obstruction, or perforation.

RESULTS

There was no significant difference in upper gastrointestinal events between the pantoprazole group (102 of 8791 events) and the placebo group (116 of 8807 events) (hazard ratio, 0.88; 95% confidence interval [CI], 0.67-1.15). Pantoprazole significantly reduced bleeding of gastroduodenal lesions (hazard ratio, 0.52; 95% confidence interval, 0.28-0.94; P = .03); this reduction was greater when we used a post-hoc definition of bleeding gastroduodenal lesion (hazard ratio, 0.45; 95% confidence interval, 0.27-0.74), although the number needed to treat still was high (n = 982; 95% confidence interval, 609-2528).

CONCLUSIONS

In a randomized placebo-controlled trial, we found that routine use of proton pump inhibitors in patients receiving low-dose anticoagulation and/or aspirin for stable cardiovascular disease does not reduce upper gastrointestinal events, but may reduce bleeding from gastroduodenal lesions. ClinicalTrials.gov ID: NCT01776424.

Who says "no" to participating in stroke clinical trials and why: an observational study from the Vancouver Stroke Program

BACKGROUND

Successful stroke trials require adequate recruitment. In this observational study, we assessed reasons for refusal to provide informed consent in eligible patients approached for clinical trial participation at the Vancouver Stroke Program.

METHODS

We assessed screening logs from four trials that were actively recruiting at our center: three randomized trials, two of which investigated different antithrombotic strategies for secondary prevention (NAVIGATE-ESUS, NCT02313909 12/2014; DATAS-II, NCT02295826 11/2014) and one that investigated surgery plus medical management versus medical management alone for primary prevention (CREST-2, NCT02089217 03/2014). The fourth study was observational and non-randomized; all participants received an external monitoring device (PROPHECY, NCT03712865 10/2018). Screening logs from June 2015 to April 2017 were reviewed retrospectively. Subsequently, we used a prospective structured case report form for screening (May 2017-March 2018). We assessed and compared refusal rates between trials, demographics of those refusing consent, and their reasons for doing so. We used descriptive statistics, chi-square and Fisher's exact tests as appropriate for non-parametric data, and t-tests for parametric data. We examined likelihood of refusal by sex using multivariable logistic regression models including age and trial intervention as co-variables.

RESULTS

A total of 235 patients (43% women) were approached for consent. More patients refused the surgical (59%) and antithrombotic trials (53%) compared with the non-randomized external monitoring device study (13%) (p < 0.001). Surgical trial refusals were primarily due to a desire for certainty in receiving a particular intervention (39%), with the majority of those patients wanting surgery. Refusals for the antithrombotic trials were mainly due to concerns with the potential side effects of the study drug (41%); refusals in the device trial were mainly due to disinterest (46%). Women refused participation more often than men (48% vs 33%). Women remained less likely to consent than men, even after adjustment for age and trial intervention (OR 0.46, 95% CI 0.26-0.82, p = 0.009).

CONCLUSIONS

Concern surrounding drug safety, randomization, and disinterest were the chief deterrents to enrolment; there were also differences in rates of consent by gender. A better understanding of why patients refuse participation in stroke trials may help to develop future patient-directed communication strategies to improve enrolment. Further research is required to better understand the reasons underlying gender disparities in consent rates.

Branch atheromatous disease diagnosed as embolic stroke of undetermined source: A sub-analysis of NAVIGATE ESUS

BACKGROUND

Branch atheromatous disease (BAD) is distinctive from large and small arterial diseases, which is single subcortical infarction larger than lacunar stroke in the territories of deep perforators without relevant arterial stenosis. BAD meets the current criteria of embolic stroke of undetermined source. We performed an exploratory analysis of BAD in patients recruited to NAVIGATE embolic stroke of undetermined source, a randomized controlled trial to compare rivaroxaban and aspirin in embolic stroke of undetermined source patients.

METHODS AND RESULTS

Among 3972 stroke patients in cerebral hemispheres with intracranial arterial imaging, 502 (12.6%) patients met the criteria for BAD. BAD was associated with younger age (years; OR: 0.97, 95% CI: 0.96-0.98), race (Asian; OR: 1.78, 95% CI: 1.44-2.21), region (Eastern Europe; OR: 2.49, 95% CI: 1.87-3.32), and higher National Institute of Health Stroke Scale (OR: 1.17, 95% CI: 1.12-1.22) at randomization. During follow-up, stroke or systemic embolism (2.5%/year vs. 6.2%/year, p = 0.0022), stroke (2.1%/year vs. 6.2%/year, p = 0.0008), and ischemic stroke (2.1%/year vs. 5.9%/year, p = 0.0013) occurred less frequently in BAD than non-BAD patients. There were no differences in annual rates of stroke or systemic embolism (2.5%/year vs. 2.5%/year, HR: 1.01, 95% CI: 0.33-3.14) or major bleeding (1.3%/year vs. 0.8%/year, HR: 1.51, 95% CI: 0.25-9.05) between rivaroxaban and aspirin groups among BAD patients.

CONCLUSIONS

BAD was relatively common, especially in Asian and from Eastern Europe among embolic stroke of undetermined source patients. Stroke severity was higher at randomization but recurrence of stroke was fewer in BAD than non-BAD patients. The efficacy and safety of rivaroxaban and aspirin did not differ among BAD patients.

Rationale, design, and baseline participant characteristics in the MRI and cognitive substudy of the cardiovascular outcomes for people using anticoagulation strategies trial

BACKGROUND

Covert vascular disease of the brain manifests as infarcts, white matter hyperintensities, and microbleeds on MRI. Their cumulative effect is often a decline in cognition, motor impairment, and psychiatric disorders. Preventive therapies for covert brain ischemia have not been established but represent a huge unmet clinical need.

AIMS

The MRI substudy examines the effects of the antithrombotic regimens in COMPASS on incident covert brain infarcts (the primary outcome), white matter hyperintensities, and cognitive and functional status in a sample of consenting COMPASS participants without contraindications to MRI.

METHODS

COMPASS is a randomized superiority trial testing rivaroxaban 2.5 mg bid plus acetylsalicylic acid 100 mg and rivaroxaban 5 mg bid against acetylsalicylic acid 100 mg per day for the combined endpoint of MI, stroke, and cardiovascular death in individuals with stable coronary artery disease or peripheral artery disease. T1-weighted, T2-weighted, T2*-weighted, and FLAIR images were obtained close to randomization and near the termination of assigned antithrombotic therapy; biomarker and genetic samples at randomization and one month, and cognitive and functional assessment at randomization, after two years and at the end of study.

RESULTS

Between March 2013 and May 2016, 1905 participants were recruited from 86 centers in 16 countries. Of these participants, 1760 underwent baseline MRI scans that were deemed technically adequate for interpretation. The mean age at entry of participants with interpretable MRI was 71 years and 23.5% were women. Coronary artery disease was present in 90.4% and 28.1% had peripheral artery disease. Brain infarcts were present in 34.8%, 29.3% had cerebral microbleeds, and 93.0% had white matter hyperintensities. The median Montreal Cognitive Assessment score was 26 (interquartile range 23-28).

CONCLUSIONS

The COMPASS MRI substudy will examine the effect of the antithrombotic interventions on MRI-determined covert brain infarcts and cognition. Demonstration of a therapeutic effect of the antithrombotic regimens on brain infarcts would have implications for prevention of cognitive decline and provide insight into the pathogenesis of vascular cognitive decline.

Promoting Independent Mobility-related Physical ACTivity (IMPACT) in an inpatient stroke rehabilitation unit: a proof-of-concept evaluation of self-management intervention

Purpose: To establish proof-of-concept of a novel rehabilitation self-management program that aims to optimize walking recovery after stroke through engaging patients in independent walking-related practice outside of supervised physiotherapy sessions.Materials and Methods: The Independent Mobility-related Physical ACTivity (IMPACT) Program is a coach-supported intervention that uses self-management strategies to empower patients to engage in additional autonomous walking-related activities after stroke during and after inpatient rehabilitation. The aim of this study was to assess whether implementation of this intervention would be associated with targeted patient behaviors; goal setting, negotiation and completion of a walking-related practice plan outside of formal therapy sessions. Using a pre-intervention/post-intervention design, the Independent Mobility-related Physical Activity program was implemented with a convenience sample of 10 adults (mean age 62.3; SD 11.7 years) within an inpatient stroke rehabilitation unit (mean stroke onset 25.3 [SD 10.5] days).Results: All participants were able to set a personal goal, negotiate an autonomous walking-related activity practice plan, and partially or completely adhere to that plan. Patients completed an average of 36 min/day of practice outside of supervised physiotherapy, practicing on weekdays and weekend days. All patients indicated that the Independent Mobility-related Physical Activity program helped them increase their activity, and indicated they would continue to practice walking-related activities beyond the coaching period.Implications for rehabilitationThe IMPACT program is a feasible self-management strategy to facilitate walking-related practice outside of supervised therapy time during inpatient stroke rehabilitation.Patients were able to engage in goal-setting and practice plan development with support of a therapist-coach.Patients who are able to stand and walk with minimal assist were able to practice walking-related activities outside of formal therapy sessions.Therapists may benefit from specific training and support to adopt self-management strategies into practice.

Abstract 41: Cerebral Microbleeds and the Effect of Anticoagulation on Outcomes in 3699 Patients With Embolic Strokes of Undetermined Source: An Exploratory Analysis of the NAVIGATE ESUS Trial

Background: Cerebral microbleeds (CMBs) are reported to predict recurrent stroke and antithrombotic-related intracerebral hemorrhage (ICH). We characterize CMBs in a well-defined population of embolic strokes of undetermined source (ESUS). Notably, we report for the first time interactions between CMBs and effects of random assignment to anticoagulant therapy.

Methods: Subgroup analyses of the NAVIGATE ESUS randomized trial comparing rivaroxaban 15 mg vs. aspirin 100 mg daily were performed. CMBs were rated on T2*-GRE sequences obtained at baseline MRI in 3699 participants (mean age 67y). Multivariable regression analyses were used to identify variables independently associated with CMBs. Cox proportional hazards models were used to estimate the contribution of CMBs to risk of recurrent stroke, ischemic stroke, ICH and all-cause mortality. Analyses followed the intent-to-treat paradigm.

Results: CMBs were present in 11% of participants. CMBs were strictly deep in 55%, lobar in 26%, and mixed in 19% of cases. Most (68%) had 1-2 CMBs, 27% had 3-10, and 5% >10. Advancing age (OR per yr 1.0, 95% CI 1.01-1.04), East Asian ethnicity (1.6, 1.0-2.4), hypertension (2.2, 1.5-3.2), multi-territorial ESUS (2.0, 1.4-2.7), chronic infarcts (1.8, 1.4-2.2), and occult ICH (5.2, 2.8-9.9) were independently associated with CMBs. During a median follow-up of 11 months, 5.1% of participants had recurrent stroke (4.8% ischemic stroke; 0.3% ICH) and 1.3% died. The presence of CMBs was associated with a 50% increased risk of recurrent stroke (HR 1.5, 95% CI 1.0-2.3), four-fold risk of ICH (4.2, 1.3-13.9), and two-fold risk of all-cause mortality (2.1, 1.1-4.3), and strictly lobar CMBs with a ~2.5-fold risk of ischemic stroke (2.3, 1.3-4.3). There were no interactions between CMBs and treatment assignments for recurrent stroke (p-value for interaction=0.2), ischemic stroke (p=0.3), or all-cause mortality (p=0.6). The hazard ratio (HR) of ICH on rivaroxaban was similar between persons with CMBs (HR 3.1, 95% CI 0.3 - 30.0) and persons without CMBs (HR 3.0, 95% CI 0.6 - 14.7; interaction p=1.0).

Conclusions: CMBs mark an increased risk of recurrent ischemic stroke, ICH and mortality in ESUS, but do not appear to influence effects of rivaroxaban, particularly on the outcome of ICH.

Rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source: a prespecified subgroup analysis from the NAVIGATE ESUS trial

BACKGROUND

Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (ESUS). Subgroup analyses from previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE ESUS trial.

METHODS

NAVIGATE ESUS was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy.

FINDINGS

Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22-1·36), and the risk was similar for those without known PFO (1·06; 0·84-1·33; p_interaction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51-8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69-4·70; p_interaction=0·68). The random-effects meta-analysis combined data from NAVIGATE ESUS with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24-0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity.

INTERPRETATION

Among patients with ESUS who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted.

FUNDING

Bayer and Janssen.