Neuroinflammation in Acute Ischemic and Hemorrhagic Stroke.

PURPOSE OF REVIEW: This review aims to provide an overview of neuroinflammation in ischemic and hemorrhagic stroke, including recent findings on the mechanisms and cellular players involved in the inflammatory response to brain injury. RECENT FINDINGS: Neuroinflammation is a crucial process following acute ischemic stroke (AIS) and hemorrhagic stroke (HS). In AIS, neuroinflammation is initiated within minutes of the ischemia onset and continues for several days. In HS, neuroinflammation is initiated by blood byproducts in the subarachnoid space and/or brain parenchyma. In both cases, neuroinflammation is characterized by the activation of resident immune cells, such as microglia and astrocytes, and infiltration of peripheral immune cells, leading to the release of pro-inflammatory cytokines, chemokines, and reactive oxygen species. These inflammatory mediators contribute to blood-brain barrier disruption, neuronal damage, and cerebral edema, promoting neuronal apoptosis and impairing neuroplasticity, ultimately exacerbating the neurologic deficit. However, neuroinflammation can also have beneficial effects by clearing cellular debris and promoting tissue repair. The role of neuroinflammation in AIS and ICH is complex and multifaceted, and further research is necessary to develop effective therapies that target this process. Intracerebral hemorrhage (ICH) will be the HS subtype addressed in this review. Neuroinflammation is a significant contributor to brain tissue damage following AIS and HS. Understanding the mechanisms and cellular players involved in neuroinflammation is essential for developing effective therapies to reduce secondary injury and improve stroke outcomes. Recent findings have provided new insights into the pathophysiology of neuroinflammation, highlighting the potential for targeting specific cytokines, chemokines, and glial cells as therapeutic strategies.

Contemporary Antiplatelet and Anticoagulant Therapies for Secondary Stroke Prevention: A Narrative Review of Current Literature and Guidelines.

PURPOSE OF REVIEW: Stroke is a leading cause of death and disability worldwide. The annual incidence of new or recurrent stroke is approximately 795,000 cases per year in the United States, of which 87% are ischemic in nature. In addition to the management of modifiable high-risk factors to reduce the risk of recurrent stroke, antithrombotic agents (antiplatelets and anticoagulants) play an important role in secondary stroke prevention. This review will discuss the published literature on the use of antiplatelets and anticoagulants in secondary prevention of acute ischemic stroke and transient ischemic attack (TIA), including their pharmacology, efficacy, and adverse effects. We will also highlight the role of dual antiplatelet therapy (DAPT) in secondary stroke prevention, along with supporting literature. RECENT FINDINGS: Single antiplatelet therapy (SAPT) with aspirin or clopidogrel reduces the risk of recurrent ischemic stroke in patients with non-cardioembolic ischemic stroke or TIA. However, as shown in recent trials, short-term DAPT with aspirin and clopidogrel or ticagrelor for 21-30 days is more effective than SAPT in patients with minor acute non-cardioembolic stroke or high-risk TIA. Although short-term DAPT is highly effective in preventing recurrent stroke, a more prolonged course can increase bleeding risks without additional benefit. DAPT for 90 days, followed by aspirin monotherapy for patients with large vessel intracranial atherosclerotic disease, is suitable for secondary stroke prevention. However, patients need to be monitored for both minor (e.g., bruising) and major (e.g., intracranial) bleeding complications. Conversely, oral warfarin and newer direct oral anticoagulant (DOACs) such as dabigatran, rivaroxaban, apixaban, and edoxaban are the agents of choice for secondary stroke prevention in patients with non-valvular cardioembolic strokes. DOACs may be preferred over warfarin due to decreased bleeding risks, including ICH, lack of need for international normalized ratio monitoring, no dietary restrictions, and limited drug-drug interactions. The choice between different antiplatelets and anticoagulants for prevention of ischemic stroke depends on the underlying stroke mechanism, cytochrome P450 2C19 polymorphisms, bleeding risk profile, compliance, drug tolerance, and drug resistance. Physicians must carefully weigh each patient's relative benefits and bleeding risks before initiating an antiplatelet/anticoagulant treatment regimen. Further studies are warranted to study the optimal duration of DAPT in symptomatic intracranial atherosclerosis since the benefit is most pronounced in the short term while the bleeding risk remains high during the extended duration of therapy.

Glycemic Gap Predicts in-Hospital Mortality in Diabetic Patients with Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: The relationship between admission hyperglycemia and intracerebral hemorrhage (ICH) outcome remains controversial. Glycemic gap (GG) is a superior indicator of glucose homeostatic response to physical stress compared to admission glucose levels. We aimed to evaluate the association between GG and in-hospital mortality in ICH. METHODS: We retrospectively identified consecutive patients hospitalized for spontaneous ICH at the 2 healthcare systems in the Twin Cities area, MN, between January 2008 and December 2017. Patients without glycosylated hemoglobin (HbA1c) test or those admitted beyond 24 hours post-ICH were excluded. Demographics, medical history, admission tests, and computed tomography data were recorded. GG was computed using admission glucose level minus HbA1c-derived average glucose. The association between GG and time to in-hospital mortality was evaluated by Cox regression analysis. Receiver operating characteristic (ROC) analysis with the DeLong test was used to evaluate the ability of GG to predict in-hospital death. RESULTS: Among 345 included subjects, 63 (25.7%) died during the hospital stay. Compared with survivors, non-survivors presented with a lower Glasgow coma scale score, larger hematoma volume, and higher white blood cells count, glucose, and GG levels at admission (p<0.001). GG remained an independent predictor of in-hospital mortality after adjusting for known ICH outcome predictors and potential confounders [adjusted hazard ratio: 1.09, 95% confidence interval (CI): 1.02-1.18, p = 0.018]. GG showed a good discriminative power (area under the ROC curve: 0.75, 95% CI: 0.68-0.82) in predicting in-hospital death and performed better than admission glucose levels in diabetic patients (p = 0.030 for DeLong test). CONCLUSIONS: Admission GG is associated with the risk of in-hospital mortality and can potentially represent a useful prognostic biomarker for ICH patients with diabetes.

The Magnitude of Blood Pressure Reduction Predicts Poor In-Hospital Outcome in Acute Intracerebral Hemorrhage.

BACKGROUND: Early systolic blood pressure (SBP) reduction is believed to improve outcome after spontaneous intracerebral hemorrhage (ICH), but there has been a limited assessment of SBP trajectories in individual patients. We aimed to determine the prognostic significance of SBP trajectories in ICH. METHODS: We collected routine data on spontaneous ICH patients from two healthcare systems over 10 years. Unsupervised functional principal components analysis (FPCA) was used to characterize SBP trajectories over first 24 h and their relationship to the primary outcome of unfavorable shift on modified Rankin scale (mRS) at hospital discharge, categorized as an ordinal trichotomous variable (mRS 0-2, 3-4, and 5-6 defined as good, poor, and severe, respectively). Ordinal logistic regression models adjusted for baseline SBP and ICH volume were used to determine the prognostic significance of SBP trajectories. RESULTS: The 757 patients included in the study were 65 ± 23 years old, 56% were men, with a median (IQR) Glasgow come scale of 14 (8). FPCA revealed that mean SBP over 24 h and SBP reduction within the first 6 h accounted for 76.8% of the variation in SBP trajectories. An increase in SBP reduction (per 10 mmHg) was significantly associated with unfavorable outcomes defined as mRS > 2 (adjusted-OR = 1.134; 95% CI 1.044-1.233, P = 0.003). Compared with SBP reduction < 20 mmHg, worse outcomes were observed for SBP reduction = 40-60 mmHg (adjusted-OR = 1.940, 95% CI 1.129-3.353, P = 0.017) and > 60 mmHg, (adjusted-OR = 1.965, 95% CI 1.011, 3.846, P = 0.047). Furthermore, the association of SBP reduction and outcome varied according to initial hematoma volume. Smaller SBP reduction was associated with good outcome (mRS 0-2) in small (< 7.42 mL) and medium-size (≥ 7.42 and < 30.47 mL) hematomas. Furthermore, while the likelihood of good outcome was low in those with large hematomas (≥ 30.47 mL), smaller SBP reduction was associated with decreasing probability of severe outcome (mRS 5-6). CONCLUSION: Our analyses suggest that in the first 6 h SBP reduction is significantly associated with the in-hospital outcome that varies with initial hematoma volume, and early SBP reduction > 40 mmHg may be harmful in ICH patients. For early SBP reduction to have an effective therapeutic effect, both target levels and optimum SBP reduction goals vis-à-vis hematoma volume should be considered.

Exploration of Multiparameter Hematoma 3D Image Analysis for Predicting Outcome After Intracerebral Hemorrhage.

BACKGROUND: Rapid diagnosis and proper management of intracerebral hemorrhage (ICH) play a crucial role in the outcome. Prediction of the outcome with a high degree of accuracy based on admission data including imaging information can potentially influence clinical decision-making practice. METHODS: We conducted a retrospective multicenter study of consecutive ICH patients admitted between 2012-2017. Medical history, admission data, and initial head computed tomography (CT) scan were collected. CT scans were semiautomatically segmented for hematoma volume, hematoma density histograms, and sphericity index (SI). Discharge unfavorable outcomes were defined as death or severe disability (modified Rankin Scores 4-6). We compared (1) hematoma volume alone; (2) multiparameter imaging data including hematoma volume, location, density heterogeneity, SI, and midline shift; and (3) multiparameter imaging data with clinical information available on admission for ICH outcome prediction. Multivariate analysis and predictive modeling were used to determine the significance of hematoma characteristics on the outcome. RESULTS: We included 430 subjects in this analysis. Models using automated hematoma segmentation showed incremental predictive accuracies for in-hospital mortality using hematoma volume only: area under the curve (AUC): 0.85 [0.76-0.93], multiparameter imaging data (hematoma volume, location, CT density, SI, and midline shift): AUC: 0.91 [0.86-0.97], and multiparameter imaging data plus clinical information on admission (Glasgow Coma Scale (GCS) score and age): AUC: 0.94 [0.89-0.99]. Similarly, severe disability predictive accuracy varied from AUC: 0.84 [0.76-0.93] for volume-only model to AUC: 0.88 [0.80-0.95] for imaging data models and AUC: 0.92 [0.86-0.98] for imaging plus clinical predictors. CONCLUSIONS: Multiparameter models combining imaging and admission clinical data show high accuracy for predicting discharge unfavorable outcome after ICH.

Transfemoral Approach to Induce Transient Middle Cerebral Artery Occlusion in Rats: The Use of Commercially Available Endovascular Wires.

BACKGROUND: Animal models of stroke play a crucial role in determining the pathophysiology of stroke progression and assessment of any new therapeutic approaches. Transient middle cerebral artery occlusion (tMCAo) in rodent models are the most common site-specific type of ischemia because of their relevance to the clinical setting. Compared with the intraluminal filament technique for inducing tMCAo, the transfemoral approach using endovascular wires is relatively a new technique METHODS: Here we present the use of commercially available wires used for neuro-endovascular surgical procedures to induce tMCAo in rats via a transfemoral approach. We used male Wistar rats in four groups to assess the effect of occlusion time (1 vs. 2 hours) and the wire type (PT2 TM 0.014″ vs. TransendTM EX, 0.014″, Boston Scientific, MA, USA). Infarct volume, edema, neurological deficits, and pro-inflammatory/anti-inflammatory blood biomarkers were used as outcome measures. RESULTS: We observed a significant effect of the wire type on the infarct volume (p value = 0.0096) where infarcts were slightly larger in the PT2 wiregroups. However, the occlusion time had no significant effect on infarct volume, even though the interaction between wire-type * occlusion-time was significant (p value = 0.024). Also, the amount of edema and blood pro-inflammatory/anti-inflammatory biomarkers were not statistically different among the wire-type and occlusion-time groups. CONCLUSIONS: The choice of appropriate endovascular wire should probably be the focus of the study design instead of the occlusion time when planning an experiment. The transfemoral approach using endovascular wires for inducing tMCAo in rats provides a more consistent outcome with fewer complications compared with suture filament models.

A Brief Review of Edema-Adjusted Infarct Volume Measurement Techniques for Rodent Focal Cerebral Ischemia Models with Practical Recommendations.

BACKGROUND: Determining cerebral infarction volume is an important part of preclinical studies to determine the benefit of potential therapies on stroke outcome. A well-known problem in determining the actual infarction volume of rodent models is the presence of edema. Because of this, algorithms must be utilized to obtain the edema-adjusted (E A)-infarct volume. Different methods based on 2,3,5-triphenyltetrazolium hydrochloride (TTC) staining have been published describing algorithms to determine the E A-infarct volume. MATERIALS AND METHODS: Simulated models of infarction and corresponding swelling were employed to determine which absolute method of calculation (Lin et al., Reglodi et al., or Belayev et al.) is the most accurate in calculating the absolute E A-infarct volume. RESULTS: The Reglodi and Belayev methods were statistically more accurate in measuring E A-infarct volume than Lin's method, p = 0.0078. Though there was no significant difference between Reglodi's and Belayev's methods for the E A-infarction volume calculation, Reglodi's approach was closer to the ground-truth infarct volume while also being simpler and more straightforward to use. CONCLUSION: We recommend that Reglodi's method, that is E A-infarct volume = infarct volume × (contralateral hemisphere/ipsilateral hemisphere), to be used in calculating E A-infarct volume in TTC stained rodent brains. Further, factors such as inhomogeneous infarction distribution in a given brain slice can also contribute to the error in volume calculation. Therefore, the average of the infarct area obtained from anterior and posterior views of a given slice should be used to account for the variation. Considering different factors, we have provided a summary recommendation for calculating the infarction volume.

Blood Pressure Variability Predicts Poor In-Hospital Outcome in Spontaneous Intracerebral Hemorrhage.

Background and Purpose- There is increasing evidence that higher systolic blood pressure variability (SBPV) may be associated with poor outcome in patients with intracerebral hemorrhage (ICH). We explored the association between SBPV and in-hospital ICH outcome. Methods- We collected 10-years of consecutive data of spontaneous ICH patients at 2 healthcare systems. Demographics, medical history, laboratory tests, computed tomography scan data, in-hospital treatments, and neurological and functional assessments were recorded. Blood pressure recordings were extracted up to 24 hours postadmission. SBPV was measured using SD, coefficient of variation, successive variation (SV), range and 1 novel index termed functional SV. The effects of SBPV on the functional outcome at discharge were evaluated by multivariate logistic and ordinal regression analyses for dichotomous and trichotomous modified Rankin Scale categorizations, respectively. In secondary analyses, associations between SBPV, history of hypertension, and hematoma expansion were explored. Results- The analysis included 762 subjects. All 5 SBPV indices were significantly associated with the probability of unfavorable outcome (modified Rankin Scale score, 4-6) in logistic models. In ordinal models, SD, coefficient of variation, range, and functional SV were found to have a significant effect on the probabilities of poor (modified Rankin Scale score, 3-4) and severe/death (modified Rankin Scale score, 5-6) outcomes. Normotensive patients had significantly lower mean SBPV compared with the untreated-hypertension cohort for all SBPV indices and compared with treated-hypertension patients for 3 out of 5 SBPV indices. Lower mean SBPV of treated-hypertension subjects compared with untreated-hypertension subjects was only detected in the SV and functional SV indices (P=0.045). None of the SBPV indices were significantly associated with the probability of hematoma expansion. Conclusions- Higher SBPV in the first 24 hours of admission was associated with unfavorable in-hospital outcome among ICH patients. Further prospective studies are warranted to understand any cause-effect relationship and whether controlling for SBPV may improve the ICH outcome.