Blood Pressure Trajectories and Outcomes After Endovascular Thrombectomy for Acute Ischemic Stroke

BACKGROUND: Data on systolic blood pressure (SBP) trajectories in the first 24 hours after endovascular thrombectomy (EVT) in acute ischemic stroke are limited. We sought to identify these trajectories and their relationship to outcomes. METHODS: We combined individual-level data from 5 studies of patients with acute ischemic stroke who underwent EVT and had individual blood pressure values after the end of the procedure. We used group-based trajectory analysis to identify the number and shape of SBP trajectories post-EVT. We used mixed effects regression models to identify associations between trajectory groups and outcomes adjusting for potential confounders and reported the respective adjusted odds ratios (aORs) and common odds ratios. RESULTS: There were 2640 total patients with acute ischemic stroke included in the analysis. The most parsimonious model identified 4 distinct SBP trajectories, that is, general directional patterns after repeated SBP measurements: high, moderate-high, moderate, and low. Patients in the higher blood pressure trajectory groups were older, had a higher prevalence of vascular risk factors, presented with more severe stroke syndromes, and were less likely to achieve successful recanalization after the EVT. In the adjusted analyses, only patients in the high-SBP trajectory were found to have significantly higher odds of early neurological deterioration (aOR, 1.84 [95% CI, 1.20–2.82]), intracranial hemorrhage (aOR, 1.84 [95% CI, 1.31–2.59]), mortality (aOR, 1.75 [95% CI, 1.21–2.53), death or disability (aOR, 1.63 [95% CI, 1.15–2.31]), and worse functional outcomes (adjusted common odds ratio,1.92 [95% CI, 1.47–2.50]). CONCLUSIONS: Patients follow distinct SBP trajectories in the first 24 hours after an EVT. Persistently elevated SBP after the procedure is associated with unfavorable short-term and long-term outcomes

Abstract P575: Impaired Distal Perfusion Predicts In-Hospital Outcome in Patients With Symptomatic Middle Cerebral Artery Stenosis

Background: Perfusion imaging is increasingly used to risk stratify patients with symptomatic intracranial stenosis. Length of hospital stay (LOS) in patients with ischemic stroke is a surrogate marker of increased morbidity. We aim to determine the association between perfusion delay on T max ( 6 sec) on perfusion weighted imaging and LOS in patients with symptomatic middle cerebral artery (MCA) stenosis. Methods: We included consecutive patients with left MCA stenosis admitted with ischemic stroke or TIA 6 sec delay, mismatch volume ≥ 15 mL based on T max 4-6 sec delay, and neither of the above mismatch patterns. The primary outcome was LOS, both as a continuous variable and categorical (≥ 7 days (prolonged LOS) vs. 6 sec and 31.3% had a mismatch volume ≥ 15 mL based on T max 4-6 sec and the median (IQR) LOS was 4 days (2-8). After adjusting for age and NIHSS, T max > 6 sec mismatch definition was associated with prolonged LOS (OR 2.90 95% CI 1.06-8.18; p=0.039) but T max 4-6 sec definition was not (OR 1.45 95% CI 0.46-4.58, p=0.528), without any interaction based on perfusion imaging modality (p interaction = 0.568). We found similar associations when LOS was considered as a continuous variable for T max > 6 sec (β coefficient=2.01, 95% CI 0.05-3.97, p=0.044) and T max 4-6 sec (β coefficient=1.24, 95% CI -0.85-3.34, p=0.244). In receiver operating curves, the optimal mismatch volume for T max > 6 sec was 10 mL (sensitivity 0.61 and specificity 0.63) whereas for T max 4-6 sec it was 39 mL (sensitivity 0.61 specificity 0.56). Conclusion: In patients with recently symptomatic MCA stenosis, the T max > 6 sec definition for mismatch, but not T max 4-6 sec, is associated with prolonged LOS. Prospective studies are needed to validate our findings and define the optimal mismatch threshold in patients with symptomatic MCA stenosis

Endothelial Shear Stress and Platelet FcγRIIa Expression in Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) has been characterized by the degree of arterial stenosis and downstream hypoperfusion, yet microscopic derangements of endothelial shear stress at the luminal wall may be key determinants of plaque growth, vascular remodeling and thrombosis that culminate in recurrent stroke. Platelet interactions have similarly been a principal focus of treatment, however, the mechanistic basis of anti-platelet strategies is largely extrapolated rather than directly investigated in ICAD. Platelet FcγRIIa expression has been identified as a potent risk factor in cardiovascular disease, as elevated expression markedly increases the risk of recurrent events. Differential activation of the platelet FcγRIIa receptor may also explain the variable response of individual patients to anti-platelet medications. We review existing data on endothelial shear stress and potential interactions with the platelet FcγRIIa receptor that may alter the evolving impact of ICAD, based on local pathophysiology at the site of arterial stenosis. Current methods for quantification of endothelial shear stress and platelet activation are described, including tools that may be readily adapted to the clinical realm for further understanding of ICAD

Endothelial Shear Stress and Platelet FcγRIIa Expression in Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) has been characterized by the degree of arterial stenosis and downstream hypoperfusion, yet microscopic derangements of endothelial shear stress at the luminal wall may be key determinants of plaque growth, vascular remodeling and thrombosis that culminate in recurrent stroke. Platelet interactions have similarly been a principal focus of treatment, however, the mechanistic basis of anti-platelet strategies is largely extrapolated rather than directly investigated in ICAD. Platelet FcγRIIa expression has been identified as a potent risk factor in cardiovascular disease, as elevated expression markedly increases the risk of recurrent events. Differential activation of the platelet FcγRIIa receptor may also explain the variable response of individual patients to anti-platelet medications. We review existing data on endothelial shear stress and potential interactions with the platelet FcγRIIa receptor that may alter the evolving impact of ICAD, based on local pathophysiology at the site of arterial stenosis. Current methods for quantification of endothelial shear stress and platelet activation are described, including tools that may be readily adapted to the clinical realm for further understanding of ICAD

Uncertainty-aware deep-learning model for prediction of supratentorial hematoma expansion from admission non-contrast head computed tomography scan

Abstract Hematoma expansion (HE) is a modifiable risk factor and a potential treatment target in patients with intracerebral hemorrhage (ICH). We aimed to train and validate deep-learning models for high-confidence prediction of supratentorial ICH expansion, based on admission non-contrast head Computed Tomography (CT). Applying Monte Carlo dropout and entropy of deep-learning model predictions, we estimated the model uncertainty and identified patients at high risk of HE with high confidence. Using the receiver operating characteristics area under the curve (AUC), we compared the deep-learning model prediction performance with multivariable models based on visual markers of HE determined by expert reviewers. We randomly split a multicentric dataset of patients (4-to-1) into training/cross-validation (n = 634) versus test (n = 159) cohorts. We trained and tested separate models for prediction of ≥6 mL and ≥3 mL ICH expansion. The deep-learning models achieved an AUC = 0.81 for high-confidence prediction of HE≥6 mL and AUC = 0.80 for prediction of HE≥3 mL, which were higher than visual maker models AUC = 0.69 for HE≥6 mL (p = 0.036) and AUC = 0.68 for HE≥3 mL (p = 0.043). Our results show that fully automated deep-learning models can identify patients at risk of supratentorial ICH expansion based on admission non-contrast head CT, with high confidence, and more accurately than benchmark visual markers

Blood Pressure After Endovascular Thrombectomy and Outcomes in Patients With Acute Ischemic Stroke An Individual Patient Data Meta-analysis

Background and Objectives To explore the association between blood pressure (BP) levels after endovascular thrombectomy (EVT) and the clinical outcomes of patients with acute ischemic stroke (AIS) patients with large vessel occlusion (LVO). Methods A study was eligible if it enrolled patients with AIS >18 years of age with an LVO treated with either successful or unsuccessful EVT and provided either individual or mean 24-hour systolic BP values after the end of the EVT procedure. Individual patient data from all studies were analyzed with a generalized linear mixed-effects model. Results A total of 5,874 patients (mean age 69 +/- 14 years; 50% women; median NIH Stroke Scale score on admission 16) from 7 published studies were included. Increasing mean systolic BP levels per 10 mm Hg during the first 24 hours after the end of the EVT were associated with a lower odds of functional improvement (unadjusted common odds ratio [OR] 0.82, 95% confidence interval [CI] 0.80-0.85; adjusted common OR 0.88, 95% CI 0.84-0.93) and modified Rankin Scale score <= 2 (unadjusted OR 0.82, 95% CI 0.79-0.85; adjusted OR 0.87, 95% CI 0.82-0.93) and a higher odds of all-cause mortality (unadjusted OR 1.18, 95% CI 1.13-1.24; adjusted OR 1.15, 95% CI 1.06-1.23) at 3 months. Higher 24-hour mean systolic BP levels were also associated with an increased likelihood of early neurologic deterioration (unadjusted OR 1.14, 95% CI 1.07-1.21; adjusted OR 1.14, 95% CI 1.03-1.24) and a higher odds of symptomatic intracranial hemorrhage (unadjusted OR 1.20, 95% CI 1.09-1.29; adjusted OR 1.20, 95% CI 1.03-1.38) after EVT. Discussion Increased mean systolic BP levels in the first 24 hours after EVT are independently associated with a higher odds of symptomatic intracranial hemorrhage, early neurologic deterioration, 3-month mortality, and worse 3-month functional outcomes

Low‐Field Portable Magnetic Resonance Imaging for Post‐Thrombectomy Assessment of Ongoing Brain Injury

Background Timely imaging is essential for patients undergoing mechanical thrombectomy (MT). Our objective was to evaluate the safety and feasibility of low‐field portable magnetic resonance imaging (pMRI) for bedside evaluation following MT. Methods Patients with suspected large‐vessel occlusion undergoing MT were screened for eligibility. All pMRI examinations were conducted in the standard ferromagnetic environment of the interventional radiology suite. Clinical characteristics, procedural details, and pMRI features were collected. Subsequent high‐field conventional MRI within 72±12 hours was analyzed. If a conventional MRI was not available for comparison, computed tomography within the same time frame was used for validation. Results Twenty‐four patients were included (63% women; median age, 76 years [interquartile range, 69–84 years]). MT was performed with a median access to revascularization time of 15 minutes (interquartile range, 8–19 minutes), and with a successful outcome as defined by a thrombolysis in cerebral infarction score of ≥2B in 90% of patients. The median time from the end of the procedure to pMRI was 22 minutes (interquartile range, 16–32 minutes). The median pMRI examination time was 30 minutes (interquartile range, 17–33 minutes). Of 23 patients with available subsequent imaging, 9 had infarct progression compared with immediate post‐MT pMRI and 14 patients did not have progression of their infarct volume. There was no adverse event related to the examination. Conclusion Low‐field pMRI is safe and feasible in a post‐MT environment and enables timely identification of ischemic changes in the interventional radiology suite. This approach can facilitate the assessment of baseline infarct burden and may help guide physiological interventions following MT

Borderzone Infarcts and Recurrent Cerebrovascular Events in Symptomatic Intracranial Arterial Stenosis: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSEIntracranial arterial stenosis (ICAS)-related stroke occurs due to three primary mechanisms with distinct infarct patterns: (1) borderzone infarcts (BZI) due to impaired distal perfusion, (2) territorial infarcts due to distal plaque/thrombus embolization, and (3) plaque progression occluding perforators. The objective of the systematic review is to determine whether BZI secondary to ICAS is associated with a higher risk of recurrent stroke or neurological deterioration. METHODSAs part of this registered systematic review (CRD42021265230), a comprehensive search was performed to identify relevant papers and conference abstracts (with ≥20 patients) reporting initial infarct patterns and recurrence rates in patients with symptomatic ICAS. Subgroup analyses were performed for studies including any BZI versus isolated BZI and those excluding posterior circulation stroke. The study outcome included neurological deterioration or recurrent stroke during follow-up. For all outcome events, corresponding risk ratios (RRs) and 95% confidence intervals (95% CI) were calculated. RESULTSA literature search yielded 4,478 records with 32 selected during the title/abstract triage for full text; 11 met inclusion criteria and 8 studies were included in the analysis (n=1,219 patients; 341 with BZI). The meta-analysis demonstrated that the RR of outcome in the BZI group compared to the no BZI group was 2.10 (95% CI 1.52-2.90). Limiting the analysis to studies including any BZI, the RR was 2.10 (95% CI 1.38-3.18). For isolated BZI, RR was 2.59 (95% CI 1.24-5.41). RR was 2.96 (95% CI 1.71-5.12) for studies only including anterior circulation stroke patients. CONCLUSIONThis systematic review and meta-analysis suggests that the presence of BZI secondary to ICAS may be an imaging biomarker that predicts neurological deterioration and/or stroke recurrence

Abstract 153: First Pass Effect in Mechanical Thrombectomy for Anterior Circulation Acute Ischemic Stroke is Modified by Procedure Time: Proposal of a New Measure for Thrombectomy Procedures

Abstract only Objective: To determine whether first pass effect (FPE) after mechanical thrombectomy (MT) for anterior circulation large vessel occlusion acute ischemic stroke (LVO-AIS) is modified by procedural time (PT). Methods: The Stroke Thrombectomy and Aneurysm Registry (STAR), a multi-center international dataset, was retrospectively analyzed for anterior circulation LVO-AIS treated by MT who achieved excellent reperfusion (TICI 2c/3). The primary outcome was good functional outcome as defined by a 90-day modified Rankin Scale (mRS) 0-2. The primary study exposure was first pass success (FPS, 1 pass vs ≥2 passes) and the secondary exposure was PT. Logistic regression models were fit-adjusted and marginal effects used to assess the interaction of PT (≤30 vs >30 minutes) and FPS, adjusting for potential confounders including time from last known well to start of MT. Results: A total of 1,310 patients had excellent reperfusion. These patients were divided into two cohorts based on PT: ≤30 minutes (777 patients, 59.3%) and > 30 minutes (533 patients, 40.7%). Good functional outcome was observed in 658 patients (50.2%). The interaction term between FPS and PT was significant (p=0.018). Individuals with FPS in ≤30 minutes had 11.5% higher adjusted predicted probability of good outcome compared with those who required ≥2 passes (58.2% vs. 46.7%, p=0.001). However, there was no significant difference in the adjusted predicted probability of good outcome based on FPS in individuals with PT >30 minutes (p=0.763). This relationship appeared identical in models with PT treated as a continuous variable. Conclusion: In a large, real-world, multi-national dataset, we find that FPE is importantly modified by PT. The added clinical benefit of FPE is lost in longer procedures (>30 minutes). These data argue for a new metric for MT procedures, namely, FPE 30 , that better represents the ideal of fast, complete reperfusion with a single pass of a thrombectomy device