TGF-β1 modulates microglial phenotype and promotes recovery after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating form of stroke that results from the rupture of a blood vessel in the brain, leading to a mass of blood within the brain parenchyma. The injury causes a rapid inflammatory reaction that includes activation of the tissue-resident microglia and recruitment of blood-derived macrophages and other leukocytes. In this work, we investigated the specific responses of microglia following ICH with the aim of identifying pathways that may aid in recovery after brain injury. We used longitudinal transcriptional profiling of microglia in a murine model to determine the phenotype of microglia during the acute and resolution phases of ICH in vivo and found increases in TGF-β1 pathway activation during the resolution phase. We then confirmed that TGF-β1 treatment modulated inflammatory profiles of microglia in vitro. Moreover, TGF-β1 treatment following ICH decreased microglial Il6 gene expression in vivo and improved functional outcomes in the murine model. Finally, we observed that patients with early increases in plasma TGF-β1 concentrations had better outcomes 90 days after ICH, confirming the role of TGF-β1 in functional recovery from ICH. Taken together, our data show that TGF-β1 modulates microglia-mediated neuroinflammation after ICH and promotes functional recovery, suggesting that TGF-β1 may be a therapeutic target for acute brain injury

Carotid web: An occult mechanism of embolic stroke

The carotid web is a proposed stroke mechanism that may underlie cryptogenic stroke, particularly in younger patients without vascular risk factors. The web appears as a shelf-like projection into the lumen of the proximal cervical internal carotid artery without evidence of calcification. It is pathologically defined as intimal fibromuscular dysplasia. Altered haemodynamics distal to the web cause flow stagnation and remote embolisation of fibrin-based clots. It is best demonstrated and diagnosed on CT angiography (CTA) of the neck because of its ability to resolve calcium and create multiplanar reconstructions. Although they can be readily visualised on CTA, carotid webs may be missed or misinterpreted because they do not typically cause haemodynamically significant stenosis and can mimic arterial dissection, non-calcified atherosclerotic plaque and intraluminal thrombus. Options for management include antiplatelet therapy, carotid endarterectomy and carotid artery stenting. Modern management strategies for cryptogenic stroke include long-Term cardiac monitoring, further investigation for structural cardiac disease and a diagnostic workup for arterial hypercoagulability, however, these strategies are not likely to capture the possibility of a carotid web. Carotid webs should be suspected in a young patient presenting with recurrent unihemispheric strokes particularly when conventional vascular risk factors are not present

Advances in Recurrent Stroke Prevention: Focus on Antithrombotic Therapies

The past decade has seen significant advances in stroke prevention. These advances include new antithrombotic agents, new options for dyslipidemia treatment, and novel techniques for surgical stroke prevention. In addition, there is greater recognition of the benefits of multifaceted interventions, including the role of physical activity and dietary modification. Despite these advances, the aging of the population and the high prevalence of key vascular risk factors pose challenges to reducing the burden of stroke. Using a cause-based framework, current approaches to prevention of cardioembolic, cryptogenic, atherosclerotic, and small vessel disease stroke are outlined in this paper. Special emphasis is given to recent trials of antithrombotic agents, including studies that have tested combination treatments and responses according to genetic factors

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

BACKGROUND AND PURPOSE: Dual antiplatelet therapy has been shown to reduce the risk of recurrent stroke in patients with minor stroke or transient ischemic attack. However, whether the effect of dual antiplatelet therapy is modified by pretreatment antiplatelet status is unclear. METHODS: This is a post hoc analysis of the POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke). Patients were divided into 2 groups based on pretreatment antiplatelet use. The primary outcome was ischemic stroke within 90 days of randomization. RESULTS: We included 4881 patients of whom 41% belonged to the no pretreatment antiplatelet. Ischemic stroke occurred in 6% and 5% in the antiplatelet pretreatment and no antiplatelet pretreatment, respectively. Antiplatelet pretreatment was not associated with the risk of ischemic stroke (adjusted hazard ratio, 1.05 [95% CI, 0.81-137]) or risk of major hemorrhage (hazard ratio, 1.10 [95% CI, 0.55-2.21]; P=0.794). The effect of dual antiplatelet therapy on recurrent ischemic stroke risk was not different in patients who were on antiplatelet before randomization (adjusted hazard ratio, 0.69 [95% CI, 0.50-0.94]) as opposed to those who were not (adjusted hazard ratio, 0.75 [95% CI, 0.50-1.12]), P for interaction = 0.685. CONCLUSIONS: In patients with minor stroke and high-risk transient ischemic attack, dual antiplatelet therapy reduces the risk of ischemic stroke regardless of premorbid antiplatelet use

Exploring the Unmet Need in Acute Ischemic Stroke Patients Not Treated With Intravenous Alteplase: The Get With The Guidelines‐Stroke Registry

Background Early administration of intravenous tissue plasminogen activator (IV alteplase) improves functional outcomes in patients with acute ischemic stroke, yet many patients are not treated with IV alteplase. There is a need to understand the reasons for nontreatment and the short‐ and long‐term outcomes in this patient population. Methods We analyzed patients ≥65 years old with a primary diagnosis of acute ischemic stroke presenting within 24 hours of time last known well (LKW) but not treated with IV alteplase from 1630 Get With The Guidelines‐Stroke hospitals in the United States between January 2016 and December 2016. We report clinical characteristics, reasons for withholding treatment, in‐hospital mortality, and 90‐day and 1‐year outcomes including costs, stratified by time from LKW to presentation (≤4.5, >4.5–6, and >6–24 hours). Results Of 39 760 patients (median age 80 [25th–75th quartiles: 73–87], 56.7% female), 19 391 (48.8%) presented within 4.5 hours of LKW. In those with documented reasons for withholding IV alteplase, the most common reasons were rapid improvement of symptoms (3985/14 782, 27.0%) and mild symptoms (3791/14 782, 25.6%). In 1100 out of 1174 (93.7%) patients presenting in the >3.0‐ to 4.5‐hour time window, the most common reason for not treating was a delay in patient arrival. The most common discharge location for those presenting ≤4.5 hours since LKW was home (8660/19 391, 44.7%). The 90‐day mortality and readmission rates were 18.9% and 23.0% in those presenting ≤4.5 hours since LKW, 19.0% and 22.2% in those presenting between 4.5 and 6 hours, and 19.1% and 23.2% in those presenting between 6 and 24 hours. Median 90‐day total in‐hospital costs remained relatively high at $9471 (Q25–Q75:$5622–$21 356) in patients presenting ≤4.5 hours since LKW. Conclusions Patients within the Get With The Guidelines‐Stroke registry not treated with IV alteplase have a high risk of readmission and mortality and have high total in‐hospital and postdischarge costs. This study may inform future efforts to address the unmet need to improve the scope of IV alteplase delivery along with other aspects of acute ischemic stroke care and, consequently, outcomes in this patient population

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

Background and purposeRandomized trials demonstrated the benefit of dual antiplatelet therapy in patients with minor ischemic stroke or high-risk transient ischemic attack. We sought to determine whether the presence of carotid stenosis was associated with increased risk of ischemic stroke and whether the addition of clopidogrel to aspirin was associated with more benefit in patients with versus without carotid stenosis.MethodsThis is a post-hoc analysis of the POINT trial (Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke) that randomized patients with minor ischemic stroke or high-risk transient ischemic attack within 12 hours from last known normal to receive either clopidogrel plus aspirin or aspirin alone. The primary predictor was the presence of ≥50% stenosis in either cervical internal carotid artery. The primary outcome was ischemic stroke. We built Cox regression models to determine the association between carotid stenosis and ischemic stroke and whether the effect of clopidogrel was modified by ≥50% carotid stenosis.ResultsAmong 4881 patients enrolled POINT, 3941 patients met the inclusion criteria. In adjusted models, ≥50% carotid stenosis was associated with ischemic stroke risk (hazard ratio, 2.45 [95% CI, 1.68-3.57], P<0.001). The effect of clopidogrel (versus placebo) on ischemic stroke risk was not significantly different in patients with <50% carotid stenosis (adjusted hazard ratio, 0.68 [95% CI, 0.50-0.93], P=0.014) versus those with ≥50% carotid stenosis (adjusted hazard ratio, 0.88 [95% CI, 0.45-1.72], P=0.703), P value for interaction=0.573.ConclusionsThe presence of carotid stenosis was associated with increased risk of ischemic stroke during follow-up. The effect of added clopidogrel was not significantly different in patients with versus without carotid stenosis. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03354429

Hyperglycemia, Risk of Subsequent Stroke, and Efficacy of Dual Antiplatelet Therapy: A Post Hoc Analysis of the POINT Trial

Background One‐quarter of all strokes are subsequent events. It is not known whether higher levels of blood glucose are associated with an increased risk of subsequent stroke after high‐risk transient ischemic attack or minor ischemic stroke. Methods and Results We performed a secondary analysis of the POINT (Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke) trial to evaluate the relationship between serum glucose hyperglycemia (≥180 mg/dL) versus normoglycemia (<180 mg/dL) before enrollment in the trial and outcomes at 90 days. The primary end point was subsequent ischemic stroke modeled by a multivariable Cox model with adjustment for age, sex, race, ethnicity, study treatment assignment, index event, and key comorbidities. Of 4878 patients included in this study, 267 had a recurrent stroke. There was a higher hazard of subsequent stroke in patients with hyperglycemia compared with normoglycemia (adjusted hazard ratio [HR], 1.50 [95% CI, 1.05–2.14]). Treatment with dual antiplatelet therapy was not associated with a reduced hazard of subsequent stroke in patients with hyperglycemia (HR, 1.18 [95% CI, 0.69–2.03]), though the wide confidence interval does not exclude a treatment effect. When modeled as a continuous variable, there was evidence of a nonlinear association between serum glucose and the hazard of subsequent stroke (P<0.001). Conclusions Hyperglycemia on presentation is associated with an increased risk of subsequent ischemic stroke after high‐risk transient ischemic attack or minor stroke. A rapid, simple assay of serum glucose may be a useful biomarker to identify patients at particularly high risk of subsequent ischemic stroke. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT0099102

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

BackgroundThe aim of this study was to determine the effect of smoking status on subsequent stroke risk in patients with minor ischemic stroke or TIA and to determine whether smoking modifies the effect of clopidogrel-based DAPT on subsequent stroke risk.MethodsThis was a post-hoc analysis of the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trial, which had a 90-day follow-up period. We used multivariable Cox regression and subgroup interaction analysis to determine the effect of smoking on the risk of subsequent ischemic stroke and major hemorrhage, respectively.ResultsData from 4877 participants enrolled in the POINT trial were analyzed. Among these, 1004 were current smokers and 3873 were non-smokers at the time of index event. Smoking was associated with a non-significant trend toward an increased risk of subsequent ischemic stroke during follow up (adjusted HR, 1.31 (95% CI, 0.97-1.78), p = 0.076). The effect of clopidogrel on ischemic stroke did not differ between non-smokers (HR, 0.74 (95% CI, 0.56-0.98), p = 0.03) and smokers (HR, 0.63 (95% CI, 0.37-1.05), p = 0.078), p for interaction = 0.572. Similarly, the effect of clopidogrel on major hemorrhage did not differ between non-smokers (hazard ratio, 1.67 (95% CI, 0.40-7.00), p = 0.481) and smokers (HR, 2.59 (95% CI, 1.08-6.21), p = 0.032), p for interaction = 0.613.ConclusionsIn this post-hoc analysis of the POINT trial we found that the effect of clopidogrel on reducing subsequent ischemic stroke as well as risk of major hemorrhage did not depend on smoking status, indicating that smokers benefit to a similar degree from DAPT as non-smokers

Atrial fibrillation as a novel risk factor for retinal stroke: A protocol for a population-based retrospective cohort study.

Central retinal artery occlusion (CRAO; retinal stroke or eye stroke) is an under-recognized, disabling form of acute ischemic stroke which causes severe visual loss in one eye. The classical risk factor for CRAO is ipsilateral carotid stenosis; however, nearly half of patients with CRAO do not have high-grade carotid stenosis, suggesting that other cardiovascular risk factors may exist for CRAO. Specifically, prior studies have suggested that cardioembolism, driven by underlying atrial fibrillation, may predispose patients to CRAO. We describe the design of an observational, population-based study in this protocol. We evaluate two specific objectives: 1) To determine if atrial fibrillation is an independent risk factor for CRAO after adjusting for medical and cardiovascular risk; 2) To determine if use of oral anticoagulation can modify the risk of CRAO for patients with atrial fibrillation. This protocol lays out our strategy for cohort definition, case and control definition, comorbidity ascertainment, and statistical methods

Higher Procedural Volumes are Associated with Faster Treatment Times, Better Functional Outcomes, and Lower Mortality in Patients Undergoing Endovascular Treatment for Acute Ischemic Stroke

Objective We aimed to characterize the association of hospital procedural volumes with outcomes among acute ischemic stroke (AIS) patients undergoing endovascular therapy (EVT). Methods This was a retrospective, observational cohort study using data prospectively collected from January 1, 2016, to December 31, 2019, in the Get With The Guidelines-Stroke registry. Participants were derived from a cohort of 60,727 AIS patients treated with EVT within 24 hours at 626 hospitals. The primary cohort excluded patients with pretreatment NIHSS6 hours, and inter-hospital transfers. There were two secondary cohorts: (1) EVT metrics cohort: excluded patients with missing data on time from door-to-arterial-puncture; (2) Intravenous thrombolysis (IVT) metrics cohort: only included patients receiving IVT ≤4.5 hours of onset.ResultsThe primary cohort (mean±SD age, 70.7 ±14.8 years; 51.2% female; median [IQR] baseline NIHSS 18.0 [13-22]; IVT use, 70.2%) comprised 21,209 patients across 595 hospitals. The EVT metrics cohort and IVT metrics cohort comprised 47,262 and 16,889 patients across 408 and 601 hospitals, respectively. Higher procedural volumes were significantly associated with higher odds (expressed as adjusted odds ratio [95% confidence interval] for every 10-case-increase in volume) of discharge to home (1.03[1.02-1.04]), functional independence at discharge (1.02[1.01-1.04]), and lower rates of in-hospital mortality (0.96[0.95-0.98]). All secondary measures were also associated with procedural volumes. Interpretation Among AIS patients primarily presenting to EVT capable hospitals (excluding those transferred from one facility to another and those suffering in-hospital strokes), EVT at hospitals with higher procedural volumes was associated with faster treatment times, better discharge outcomes, and lower rates of in-hospital mortality