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.

Dabigatran for Prevention of Stroke after Embolic Stroke of Undetermined Source.

BACKGROUND: Cryptogenic strokes constitute 20 to 30% of ischemic strokes, and most cryptogenic strokes are considered to be embolic and of undetermined source. An earlier randomized trial showed that rivaroxaban is no more effective than aspirin in preventing recurrent stroke after a presumed embolic stroke from an undetermined source. Whether dabigatran would be effective in preventing recurrent strokes after this type of stroke was unclear. METHODS: We conducted a multicenter, randomized, double-blind trial of dabigatran at a dose of 150 mg or 110 mg twice daily as compared with aspirin at a dose of 100 mg once daily in patients who had had an embolic stroke of undetermined source. The primary outcome was recurrent stroke. The primary safety outcome was major bleeding. RESULTS: A total of 5390 patients were enrolled at 564 sites and were randomly assigned to receive dabigatran (2695 patients) or aspirin (2695 patients). During a median follow-up of 19 months, recurrent strokes occurred in 177 patients (6.6%) in the dabigatran group (4.1% per year) and in 207 patients (7.7%) in the aspirin group (4.8% per year) (hazard ratio, 0.85; 95% confidence interval [CI], 0.69 to 1.03; P = 0.10). Ischemic strokes occurred in 172 patients (4.0% per year) and 203 patients (4.7% per year), respectively (hazard ratio, 0.84; 95% CI, 0.68 to 1.03). Major bleeding occurred in 77 patients (1.7% per year) in the dabigatran group and in 64 patients (1.4% per year) in the aspirin group (hazard ratio, 1.19; 95% CI, 0.85 to 1.66). Clinically relevant nonmajor bleeding occurred in 70 patients (1.6% per year) and 41 patients (0.9% per year), respectively. CONCLUSIONS: In patients with a recent history of embolic stroke of undetermined source, dabigatran was not superior to aspirin in preventing recurrent stroke. The incidence of major bleeding was not greater in the dabigatran group than in the aspirin group, but there were more clinically relevant nonmajor bleeding events in the dabigatran group. (Funded by Boehringer Ingelheim; RE-SPECT ESUS ClinicalTrials.gov number, NCT02239120.).

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.

Reexamination of the Embolic Stroke of Undetermined Source Concept.

Occult atrial fibrillation (AF) is a leading cause of stroke of unclear cause. The optimal approach to secondary stroke prevention for these patients remains elusive. The term embolic stroke of undetermined source (ESUS) was coined to describe ischemic strokes in which the radiographic features demonstrate territorial infarcts resembling those seen in patients with confirmed sources of embolism but without a clear source of embolism detected. It was assumed that patients with ESUS had a high rate of occult AF and would benefit from treatment with direct oral anticoagulants, which are at least as effective as vitamin K antagonists for secondary stroke prevention in patients with AF, but with a much lower risk of intracerebral hemorrhage. Two recent large randomized trials failed to show superiority of direct oral anticoagulants over aspirin in ESUS patients. These findings prompt a reexamination of the ESUS concept, with the goal of improving specificity for detecting patients with a cardioembolic cause. Based on the negative trial results, there is renewed interest in the role of long-term cardiac monitoring for AF in patients who fit the current ESUS definition, as well as the clinical implication of detecting AF. Ongoing trials are exploring these questions. Current ESUS definitions do not accurately detect the patients who should be prescribed direct oral anticoagulants, potentially because occult AF is less common than expected in these patients and/or anticoagulants may be less beneficial in patients with ESUS but no AF than they are for patients with stroke with established AF. More specific criteria to identify patients who may be at higher risk for occult AF and reduce their risk of subsequent stroke have been developed and are being tested in ongoing clinical trials.

Effects of ML351 and tissue plasminogen activator combination therapy in a rat model of focal embolic stroke.

Thrombolytic stroke therapy with tissue plasminogen activator (tPA) is limited by risks of hemorrhagic transformation (HT). We have reported that a new 12/15-lipoxygenase (12/15-LOX) inhibitor ML351 reduced tPA related HT in mice subjected to experimental stroke under anticoagulation. In this study, we asked whether ML351 can ameliorate tPA induced HT in an embolic stroke model. Rats were subjected to embolic middle cerebral artery occlusion with 2 or 3 hr ischemia and tPA infusion, with or without ML351. Regional cerebral blood flow was monitored 2 hr after ischemia and continuously monitored for 1 hr after treatment for determining reperfusion. Hemoglobin was determined in brain homogenates and infarct volume was quantified at 24 hr after stroke.12/15-LOX, cluster of differentiation 68(CD68), immunoglobulin G (IgG), and tight junction proteins expression was detected by immunohistochemistry. ML351 significantly reduced tPA related hemorrhage after stroke without affecting its thrombolytic efficacy. ML351 also reduced blood-brain barrier disruption and improved preservation of junction proteins. ML351 and tPA combination improved neurological deficit of rats even though ML351 did not further reduce the infarct volume compared to tPA alone treated animals. Pro-inflammatory cytokines were suppressed by ML351 both in vivo and in vitro experiments. We further showed that ML351 suppressed the expression of c-Jun-N-terminal kinase (JNK) in brains and microglia cultures, whereas exogenous 12-HETE attenuated this effect in vitro. In conclusion, ML351 and tPA combination therapy is beneficial in ameliorating HT after ischemic stroke. This protective effect is probably because of 12/15-LOX inhibition and suppression of JNK-mediated microglia/macrophage activation.

Rivaroxaban for Stroke Prevention after Embolic Stroke of Undetermined Source.

BACKGROUND: Embolic strokes of undetermined source represent 20% of ischemic strokes and are associated with a high rate of recurrence. Anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, may result in a lower risk of recurrent stroke than aspirin. METHODS: We compared the efficacy and safety of rivaroxaban (at a daily dose of 15 mg) with aspirin (at a daily dose of 100 mg) for the prevention of recurrent stroke in patients with recent ischemic stroke that was presumed to be from cerebral embolism but without arterial stenosis, lacune, or an identified cardioembolic source. The primary efficacy outcome was the first recurrence of ischemic or hemorrhagic stroke or systemic embolism in a time-to-event analysis; the primary safety outcome was the rate of major bleeding. RESULTS: A total of 7213 participants were enrolled at 459 sites; 3609 patients were randomly assigned to receive rivaroxaban and 3604 to receive aspirin. Patients had been followed for a median of 11 months when the trial was terminated early because of a lack of benefit with regard to stroke risk and because of bleeding associated with rivaroxaban. The primary efficacy outcome occurred in 172 patients in the rivaroxaban group (annualized rate, 5.1%) and in 160 in the aspirin group (annualized rate, 4.8%) (hazard ratio, 1.07; 95% confidence interval [CI], 0.87 to 1.33; P=0.52). Recurrent ischemic stroke occurred in 158 patients in the rivaroxaban group (annualized rate, 4.7%) and in 156 in the aspirin group (annualized rate, 4.7%). Major bleeding occurred in 62 patients in the rivaroxaban group (annualized rate, 1.8%) and in 23 in the aspirin group (annualized rate, 0.7%) (hazard ratio, 2.72; 95% CI, 1.68 to 4.39; P<0.001). CONCLUSIONS: Rivaroxaban was not superior to aspirin with regard to the prevention of recurrent stroke after an initial embolic stroke of undetermined source and was associated with a higher risk of bleeding. (Funded by Bayer and Janssen Research and Development; NAVIGATE ESUS ClinicalTrials.gov number, NCT02313909 .).

Prognostic analysis of different therapeutic regimens in patients with acute cardiogenic cerebral embolism.

BACKGROUND: Few studies focused on the functional outcomes of patients at 3 months after receiving intravenous thrombolysis, anticoagulation, or antiplatelet therapy within 4.5 h of onset of the cardiogenic cerebral embolism (CCE) subtype. METHODS: The purpose of this retrospective study was to analyse the clinical data of patients with acute CCE and compare the 3-month functional prognoses of patients after administration of different antithrombotic therapies within 4.5 h of stroke onset. A total of 335 patients with CCE hospitalized in our institution were included in this study. The patients were stratified according to the hyperacute treatment received, and baseline clinical and laboratory data were analysed. A 3-month modified Rankin scale (mRS) score of 0-2 was defined as an excellent functional outcome. RESULTS: A total of 335 patients were divided into thrombolytic (n = 78), anticoagulant (n = 88), and antiplatelet therapy groups (n = 169). A total of 164 patients had a good prognosis at 3 months (mRS ≤ 2). After adjustments were made for age and National Institute of Health Stroke Scale (NIHSS) score, each group comprised 38 patients, and there were no significant differences in sex composition, complications, lesion characteristics, or Oxfordshire Community Stroke Project (OSCP) classification among the three groups. The plasma D-dimer level (µg/ml) in the thrombolytic group was significantly higher than those in the anticoagulant and antiplatelet groups [3.07 (1.50,5.62), 1.33 (0.95,1.89), 1.61 (0.76,2.96), P < 0.001]. After one week of treatment, the reduction in NIHSS in the thrombolytic group was significantly greater than those in the other two groups [3.00 (1.00, 8.00), 1.00 (0.00, 5.00), 1.00 (0.00, 2.00), P = 0.025]. A total of 47 patients (41.2 %) had an mRS score of ≤ 2 at 3 months, and 23 patients died (20.2 %). There was no significant difference in the proportion of patients with a good prognosis or the mortality rate among the three groups (P = 0.363, P = 0.683). CONCLUSIONS: Thrombolytic therapy is effective at improving short-term and 3-month prognoses. Anticoagulant therapy may be a safe and effective treatment option for patients with the cardiac stroke subtype who fail to receive intravenous recombinant tissue plasminogen activator (r-tPA) thrombolysis within 4.5 h in addition to antiplatelet therapy, as recommended by the guidelines.

Clinical Outcome of Patients With Large Vessel Occlusion and Low National Institutes of Health Stroke Scale Scores: Subanalysis of the RESCUE-Japan Registry 2.

Background and Purpose- The treatment and prognosis of acute large vessel occlusion with mild symptoms have not been sufficiently studied. The present study aimed to investigate the clinical or radiological predictors of clinical outcome in patients with stroke with mild symptoms due to acute large vessel occlusion. Methods- Of 2420 patients with acute large vessel occlusion in the RESCUE-Japan Registry 2 (Recovery by Endovascular Salvage for Cerebral Ultra-Acute Embolism-Japan Registry 2), a multicenter prospective registry in Japan, patients with modified Rankin Scale scores of 0 to 2 before onset and initial National Institutes of Health Stroke Scale (NIHSS) scores of 0 to 5 were examined in post hoc analysis. We examined the clinical and radiological characteristics associated with a favorable outcome (modified Rankin Scale score, 0-2 at 90 days) using multivariate analysis, as well as the factors associated with a favorable outcome in patients treated with endovascular therapy. Results- We analyzed 272 patients (median age, 73 years; median NIHSS score on admission, 3). Eighty-six (31.6%) patients were treated with intravenous recombinant tissue-type plasminogen activator, 54 (19.9%) underwent endovascular therapy, and 208 (76.5%) showed a favorable outcome. In multivariate analysis, age <75 years (odds ratio [OR], 2.42 [95% CI, 1.30-4.50]), initial NIHSS score 0 to 3 (OR, 3.08 [95% CI, 1.59-5.98]), intravenous recombinant tissue-type plasminogen activator (OR, 2. 86 [95% CI, 1.32-6.21]), and blood glucose level ≤140 mg/dL (OR, 2.37 [95% CI, 1.22-4.60]) were independently associated with a favorable outcome. However, endovascular therapy was not associated with a favorable outcome (OR, 1.65 [95% CI, 0.71-3.88]). Among 54 patients treated with endovascular therapy, good reperfusion status was more common in the favorable outcome group (88.6% versus 60.0%; P<0.05). Conclusions- Younger age, lower initial NIHSS score, intravenous recombinant tissue-type plasminogen activator, and absence of hyperglycemia were independently associated with a favorable outcome in patients with acute large vessel occlusion with low NIHSS scores. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02419794.

High-Sensitivity Cardiac Troponin T for Risk Stratification in Patients With Embolic Stroke of Undetermined Source.

BACKGROUND AND PURPOSE: Optimal secondary prevention for patients with embolic stroke of undetermined source (ESUS) remains unknown. We aimed to assess whether high-sensitivity cardiac troponin T (hs-cTnT) levels are associated with major vascular events and whether hs-cTnT may identify patients who benefit from anticoagulation following ESUS. METHODS: Data were obtained from the biomarker substudy of the NAVIGATE ESUS trial, a randomized controlled trial testing the efficacy of rivaroxaban versus aspirin for secondary stroke prevention in ESUS. Patients were dichotomized at the hs-cTnT upper reference limit (14 ng/L, Gen V, Roche Diagnostics). Cox proportional hazard models were computed to explore the association between hs-cTnT, the combined cardiovascular end point (recurrent stroke, myocardial infarction, systemic embolism, cardiovascular death), and recurrent ischemic stroke. RESULTS: Among 1337 patients enrolled at 111 participating centers in 18 countries (mean age 67±9 years, 61% male), hs-cTnT was detectable in 95% and at/above the upper reference limit in 21%. During a median follow-up of 11 months, the combined cardiovascular end point occurred in 68 patients (5.0%/y, rivaroxaban 28 events, aspirin 40 events; hazard ratio, 0.67 [95% CI, 0.41-1.1]), and recurrent ischemic stroke occurred in 50 patients (4.0%/y, rivaroxaban 16 events, aspirin 34 events, hazard ratio 0.45 [95% CI, 0.25-0.81]). Annualized combined cardiovascular end point rates were 8.2% (9.5% rivaroxaban, 7.0% aspirin) for those above hs-cTnT upper reference limit and 4.8% (3.1% rivaroxaban, 6.6% aspirin) below with a significant treatment modification (P=0.04). Annualized ischemic stroke rates were 4.7% above hs-cTnT upper reference limit and 3.9% below, with no suggestion of an interaction between hs-cTnT and treatment (P=0.3). CONCLUSIONS: In patients with ESUS, hs-cTnT was associated with increased cardiovascular event rates. While fewer recurrent strokes occurred in patients receiving rivaroxaban, outcomes were not stratified by hs-cTn results. Our findings support using hs-cTnT for cardiovascular risk stratification but not for decision-making regarding anticoagulation therapy in patients with ESUS. 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.

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

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

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.

An Embolic Stroke in a Patient With PROC p.Lys193del.

We report a 58-year-old woman who suddenly developed brain infarction with weakness of the left lower extremity and left perioral dysesthesia during postoperative tamoxifen therapy for breast cancer and prednisolone therapy for rheumatoid arthritis. Diffusion-weighted images detected multiple areas of hyperintensity in the posterior circulation system of the brain. Despite extensive examinations, we could not identify any embolic sources except hypoplasia of the right vertebral artery. We found decreased activity of protein C against its antigen level (activity: 59% versus antigen: 122%) with enhanced activity of coagulation factor VIII (178%) and von Willebrand factor (285%). DNA sequencing identified trinucleotide deletion of the PROC gene leading to 1 amino acid deletion at Lys-193 (p.Lys193del). We speculate that the PROC gene polymorphism may have participated in tamoxifen- and prednisolone- associated hypercoagulable state, leading to development of an embolic stroke in this patient.

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.

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.

Predictors of Recurrent Ischemic Stroke in Patients with Embolic Strokes of Undetermined Source and Effects of Rivaroxaban Versus Aspirin According to Risk Status: The NAVIGATE ESUS Trial.

BACKGROUND: Embolic stroke of undetermined source (ESUS) identifies patients with cryptogenic ischemic stroke presumed due to embolism from several unidentified sources. Among patients with recent ESUS, we sought to determine independent predictors of recurrent ischemic stroke during treatment with aspirin or rivaroxaban and to assess the relative effects of these treatments according to risk. METHODS: Exploratory analyses of 7213 participants in the NAVIGATE ESUS international trial who were randomized to aspirin 100 mg/day or rivaroxaban 15 mg/day and followed for a median of 11 months, during which time there were 309 first recurrent ischemic strokes (4.6% per year). Baseline features were correlated with recurrent stroke by multivariate analysis. RESULTS: The 7 independent predictors of recurrent stroke were stroke or transient ischemic attack (TIA) prior to the qualifying stroke (hazard ratio [HR] 2.03 95% confidence internal [CI] 1.58-2.60), current tobacco user (HR 1.62, 95% CI 1.24-2.12), age (HR 1.02 per year increase, 95%CI 1.01-1.03), diabetes (HR 1.28, 95% CI 1.01-1.64), multiple acute infarcts on neuroimaging (HR 1.49, 95% CI 1.09-2.02), aspirin use prior to qualifying stroke (HR 1.34, 95% CI 1.02-1.70), and time from qualifying stroke to randomization (HR .98, 95% CI .97-.99). The rate of recurrent stroke rate was 2.6% per year for participants without any of these risk factors, and increased by an average of 45% for each independent predictor (P < .001). There were no significant interactions between treatment effects and independent stroke predictors or stroke risk status. CONCLUSIONS: In this large cohort of ESUS patients, several features including prior stroke or TIA, advanced age, current tobacco user, multiple acute infarcts on neuroimaging, and diabetes independently identified those with an increased risk of ischemic stroke recurrence. The relative effects of rivaroxaban and aspirin were similar across the spectrum of independent stroke predictors and recurrent stroke risk status.

Paradoxical Brain Embolism Caused by Isolated Pulmonary Arteriovenous Fistula Successfully Treated with Recombinant Tissue Plasminogen Activator.

Pulmonary arteriovenous fistula (PAVF), a vessel malformation connecting the pulmonary circulation to the systemic circulation while bypassing the pulmonary capillaries, can cause paradoxical cerebral infarction. It is often associated with hereditary hemorrhagic telangiectasia (HHT), a genetic disease characterized by multiple dermal, mucosal, and visceral telangiectasia causing recurrent bleeding. Paradoxical cerebral embolism caused by PAVF without HHT is rare. Here, we report a patient with isolated PAVF who experienced an ischemic stroke caused by a paradoxical embolism from deep venous thrombosis; the patient was successfully treated with recombinant tissue plasminogen activator. She presented with a decrease in arterial oxygen saturation to 91%, and lung disease was suspected. A PAVF was subsequently found in the right S6 region using contrast computed tomography. Interventional radiologists successfully occluded the shunt using 6 microcoils. PAVF should be considered when determining the pathogenesis of cerebral ischemia in patients with hypoxia, which can be the only symptom of PAVF.

Statin Pretreatment and Microembolic Signals in Large Artery Atherosclerosis.

Background and Purpose- Scarce data indicate that statin pretreatment (SP) in patients with acute cerebral ischemia because of large artery atherosclerosis may be related to lower risk of recurrent stroke because of a decreased incidence of microembolic signals (MES) during transcranial Doppler monitoring. Methods- We performed a systematic review and meta-analysis of available observational studies reporting MES presence/absence or MES burden, categorized according to SP status, in patients with acute cerebral ischemia because of symptomatic (≥50%) large artery atherosclerosis. In studies with partially-published data, authors were contacted for previously unpublished information. We also performed a sensitivity analysis of studies with data on MES burden categorized according to SP status, and an additional subgroup analysis in patients receiving higher-dose SP (atorvastatin 80 mg or rosuvastatin 40 mg daily). Results- Seven eligible study protocols were identified (610 patients, 54% with SP). SP was associated with a reduced risk of MES detection during transcranial Doppler monitoring (risk ratio=0.67; 95% CI, 0.45-0.98), with substantial heterogeneity between studies ( I2=52%). In studies reporting MES burden (n=4), a significantly lower number of MES were identified in patients with compared with those without SP (mean difference=-0.92; 95% CI, -1.64 to -0.19), with no evidence of heterogeneity between studies ( I2=49%). Subgroup analysis revealed that higher-dose SP reduced the risk of detecting MES (risk ratio=0.23; 95% CI, 0.06-0.88), with no evidence of heterogeneity between studies ( I2=0%). Conclusions- SP seems to be associated with a lower incidence and burden of MES in patients with acute cerebral ischemia because of large artery atherosclerosis.

Early administration of pyrrolidine dithiocarbamate extends the therapeutic time window of tissue plasminogen activator in a male rat model of embolic stroke.

Tissue plasminogen activator (tPA) is used in fewer than 4% of patients after ischemic stroke because of its narrow therapeutic time window. We tested whether pyrrolidine dithiocarbamate (PDTC), a drug with multiple mechanisms to provide neuroprotection, can be used to extend the therapeutic time window of tPA. Three-month-old male Sprague-Dawley rats were subjected to embolic stroke in the area supplied by the right middle cerebral artery. tPA at 10 mg/kg was given intravenously 4 h after the onset of stroke. PDTC at 50 mg/kg was given via gastric gavage at 30 min or 4 h after the onset of stroke. Two days after the stroke, neurological outcome was evaluated and the right frontal cortex area 1 (Fr1), an ischemic penumbral region, was harvested for analysis. PDTC given at 30 min after the stroke reduced infarct volumes and improved neurological functions no matter whether the rats received tPA. PDTC also reduced tPA-increased hemorrhagic volumes. Consistent with these results, PDTC in the presence or absence of tPA treatment attenuated the increase of proinflammatory cytokines, oxidative stress and matrix metalloprotease 2 activity in the right Fr1. However, PDTC given at 4 h after the onset of stroke did not improve the neurological outcome of rats treated with or without tPA. Our results suggest that PDTC given at an early time point but not in a delayed phase provides neuroprotection against embolic stroke and may be used to extend the therapeutic time window of tPA.

Clinical outcome of cardioembolic stroke treated by intravenous thrombolysis.

INTRODUCTION: Cardioembolic stroke (CS) in patients without thrombolytic treatment is associated with a worse clinical outcome and higher mortality compared to other types of stroke. The aim of this study was to determine the clinical outcome of CS in patients treated by intravenous thrombolysis (IVT). MATERIAL AND METHODOLOGY: Data of patients from the SITS-EAST register (Safe Implementation of Treatments in Stroke) were analyzed in patients who received IVT treatment from 2000 to April 2014. The effect of the stroke etiology according to ICD-10 classification on outcome was analyzed using a univariate and multivariate analysis. The outcomes were assessed as follows: excellent clinical outcome (modified Rankin scale (mRS) 0-1) at 3 months, the rate of symptomatic intracranial hemorrhage (sICH), mortality, and improvement at 24 hours after IVT. RESULTS: Data of 13 772 patients were analyzed. CS represented 30% of all strokes. The mean age of patients with CS, atherothrombotic stroke, lacunar stroke, and other stroke was 70.8, 66.7, 66.2, and 63.3 years, respectively (P < .001). Severity of stroke on admission by median NIHSS score was 13 points in patients with CS, 12 points - in atherothrombotic stroke, 7 points - in lacunar stroke, and 10 points-in other stroke types (P < .001). No difference in mortality was detected among atherothrombotic and CS; however, atherothrombotic strokes had higher odds of sICH [OR = 1.63 (95% CI: 1.07-2.47), P = .023], lower odds of early improvement [OR = 0.79 (95% CI: 0.72-0.86), P < .001], and excellent clinical outcome [OR = 0.77 (95% CI: 0.67-0.87), P < .001] compared with CS. CONCLUSIONS: Cardioembolic strokes are not associated with increased mortality. Patients with CS are less likely to have sICH and have better outcome after IVT.