Hemodynamics of Leptomeningeal Collaterals after Large Vessel Occlusion and Blood Pressure Management with Endovascular Treatment

Interaction of brain imaging features and effects of intensive blood pressure lowering after endovascular treatment for acute ischaemic stroke: the pre-specified secondary analyses of ENCHANTED2/MT trial

Background

The second Enhanced Control of Hypertension and Thrombectomy Stroke Study (ENCHANTED2/MT) was terminated early when the intensive blood pressure lowering to a systolic level of 120 mm Hg or lower, compared to 140-180 mm Hg, was harmful in patients who received successful endovascular therapy for acute ischaemic stroke due to large-vessel occlusion. We aimed to determine the interaction of key brain imaging features and the effect of treatment on clinical outcomes.

Methods

ENCHANTED2/MT was a prospective, randomised, open-label, blinded-endpoint, controlled trial that aimed to assess the effectiveness of different intensities of blood pressure control on the functional independence in patients who had received successful endovascular therapy for acute ischaemic stroke from large-vessel occlusion at 44 hospitals in China between July 20, 2020 and March 7, 2022. In these pre-specified secondary analyses, neuroradiologists reviewed the baseline brain images of participants (computerised tomography [CT], CT with angiography [CTA] and digital subtraction angiography [DSA]) blind to treatment allocation, to determine the degree of cerebral infarction on the Alberta Stroke Program Early CT Score (ASPECTS), collateral status according to modified TAN score, and degree of reperfusion on the expanded Treatment In Cerebral Infarction (eTICI) scale. The primary outcome was functional independence, according to the distribution of scores on the modified Rankin scale (range 0 [no symptoms] to 6 [death]) at 90 days. Multivariable logistic regression analysis was done according to the modified intention-to-treat principle in all participants with available outcome data. ENCHANTED2/MT is registered with ClinicalTrials.gov, NCT04140110.

Findings

Of 816 participants in the trial, in whom 407 were assigned to more intensive blood pressure lowering and 409 were assigned to less intensive blood pressure lowering treatment, there were 533, 372, and 757 participants with available data for ASPECTS, collateral flow, and eTICI analyses, respectively. Intensive blood pressure lowering was associated with worse functional independence in participants with complete reperfusion (eTICI 3: adjusted odds ratio [aOR] 1.51, 95% CI 1.14-2.02) but not in those with incomplete reperfusion (eTICI 2b/c: aOR 1.29, 95% CI 0.73-2.28), without significant interaction (pinteraction = 0.82). There was no significant interaction between blood pressure treatment and ASPECTS (0-5 vs. 6-10: aOR 1.27, 95% CI 0.77-2.11 vs. aOR 1.37, 95% CI 0.91-2.07; pinteraction = 0.14) on functional independence. However, more intensive blood pressure lowering treatment was associated with worse functional independence in participants with poor collateral status (aOR 1.99, 95% CI 1.11-3.57) compared to those with good collateral status (aOR 0.87, 95% CI 0.53-1.45), with a moderate level of interaction (pinteraction = 0.037).

Interpretation

Our study indicates that collateral status may help identify patients at risk from intensive blood pressure lowering treatment to a systolic target of 120 mm Hg or lower, in patients undergoing endovascular therapy for acute ischaemic stroke from large-vessel occlusion.

Funding

The Shanghai Hospital Development Center; National Health and Medical Research Council of Australia; Medical Research Foundation (MRF) of the UK; AstraZeneca; China Stroke Prevention; Shanghai Changhai Hospital, Science and Technology Commission of Shanghai Municipality; Takeda China; Hasten Biopharmaceutic; Genesis Medtech; Penumbra.

Association of reverse dipping blood pressure with mortality among critically ill patients with ischemic stroke

Reverse dipping blood pressure, generally regarded as a pathological condition, is frequently observed in patients with acute stroke. We aimed to assess the association of reverse dipping blood pressure with in-hospital mortality among critically ill patients with ischemic stroke. This is a retrospective study of patients in the Medical Information Mart for Intensive Care IV database with ischemic stroke requiring intensive care unit admission. Diurnal (9:00-21:00) and nocturnal (1:00-6:00) mean arterial pressures (MAPs) were collected. Reverse dipping was defined as having an average nocturnal MAP higher than the average diurnal MAP. Multivariable binary logistic regression analysis was used to assess the association of reverse dipping with in-hospital mortality. A total of 2080 patients (median age, 73 years; 50.3% female) were enrolled, among which 681 patients (32.7%) had reverse dipping. Patients with reverse dipping blood pressure had a higher in-hospital mortality compared to those without (19.8% vs. 11.4%, p < 0.001). After adjusting for potential confounders, reverse dipping was associated with a higher likelihood of in-hospital mortality (adjusted OR, 1.59; 95% CI 1.21-2.11; p = 0.001). Reverse dipping blood pressure was associated with a higher mortality rate among critically ill patients with ischemic stroke. The circadian rhythm of blood pressure should warrant more attention in cerebrovascular neurocritical care.

Collateral blood vessels in stroke and ischemic disease: Formation, physiology, rarefaction, remodeling

Collateral blood vessels are unique, naturally occurring endogenous bypass vessels that provide alternative pathways for oxygen delivery in obstructive arterial conditions and diseases. Surprisingly however, the capacity of the collateral circulation to provide protection varies greatly among individuals, resulting in a significant fraction having poor collateral circulation in their tissues. We recently reviewed evidence that the presence of naturally-occurring polymorphisms in genes that determine the number and diameter of collaterals that form during development (ie, genetic background), is a major contributor to this variation. The purpose of this review is to summarize current understanding of the other determinants of collateral blood flow, drawing on both animal and human studies. These include the level of smooth muscle tone in collaterals, hemodynamic forces, how collaterals form during development (collaterogenesis), de novo formation of additional new collaterals during adulthood, loss of collaterals with aging and cardiovascular risk factor presence (rarefaction), and collateral remodeling (structural lumen enlargement). We also review emerging evidence that collaterals not only provide protection in ischemic conditions but may also serve a physiological function in healthy individuals. Primary focus is on studies conducted in brain, however relevant findings in other tissues are also reviewed, as are questions for future investigation.

Exploring the optimal lower blood pressure boundary during endovascular thrombectomy in patients with large vessel occlusion

BACKGROUND

Current guidelines advocate for maintaining BP level below 180/105 mmHg during EVT, determining the safe lower boundary remains primarily consensus-driven by experts. This study aims to delve into the correlation between various targets of lower boundary for systolic and diastolic BP (SBP and DBP) during EVT and 3-month functional outcomes.

METHODS

A cohort study was conducted across two EVT-capable centers, enrolling patients with large artery occlusion undergoing EVT within 8 h of stroke onset. Mean BP values during EVT were meticulously recorded, and logistic regression models were utilized to evaluate the correlation between outcomes and diverse lower boundary targets for SBP and DBP. Additionally, logistic regression models investigated the relationship between periprocedural BP variability and subsequent outcomes.

RESULTS

Among the 201 patients included, having a SBP higher than 130 or 140 mmHg showed an independent association with increased good functional outcomes at 3 months (adjusted odds ratio, aOR 2.80, 95% Cis, 1.26-6.39 for 140 mmHg; aOR 2.34, 95% Cis, 1.03-5.56 for 130 mmHg). Additionally, an SBP exceeding 130 mmHg was correlated with decreased 3-month mortality (aOR, 0.24, 95% CI 0.07-0.74). No significant relationship was observed between DBP and functional outcomes. Patients with higher periprocedural SBP coefficient variance exhibited a decreased rate of good functional outcomes at 3 months (aOR, 0.42, 95% CI, 0.18-0.96).

CONCLUSION

A SBP range above 130-140 mmHg could potentially serve as a safe lower boundary during EVT, while minimizing BP fluctuations may correlate with improved post-EVT functional outcomes.

A novel NIR-II albumin-escaping probe for cerebral arteries and perfusion imaging in stroke mice model

In order to guide the formulation of post-stroke treatment strategy in time, it is necessary to have real-time feedback on collateral circulation and revascularization. Currently used near-infrared II (NIR-II) probes have inherent binding with endogenous albumin, resulting in significant background signals and uncontrollable pharmacokinetics. Therefore, the albumin-escaping properties of the new probe, IR-808AC, was designed, which achieved timely excretion and low background signal, enabling the short-term repeatable injection for visualization of cerebral vessels and perfusion. We further achieved continuous observation of changes in collateral vessels and perfusion during the 7-d period in middle cerebral artery occlusion mice using IR-808AC in vivo. Furthermore, using IR-808AC, we confirmed that remote ischemic conditioning could promote collateral vessels and perfusion. Finally, we evaluated the revascularization after thrombolysis on time in embolic stroke mice using IR-808AC. Overall, our study introduces a novel methodology for safe, non-invasive, and repeatable assessment of collateral circulation and revascularization in real-time that is crucial for the optimization of treatment strategies.

Blood pressure targets after successful reperfusion in mechanical thrombectomy for acute ischemic stroke: an updated systematic review and meta-analysis of randomized clinical trials

BACKGROUND

This study sought to determine whether intensive blood pressure (BP) control for patients with successful reperfusion following acute ischemic stroke (AIS) is beneficial, compared to conventional BP management.

METHODS

PubMed, Embase, and Cochrane databases were systematically searched for randomized controlled trials (RCTs) on the subject. The studied outcomes included dependency or death at 90 days (modified Rankin Scale [mRS] 3-6); severe disability at 90 days (mRS 3-5); mortality at 90 days; and symptomatic intracranial hemorrhage. Odds ratios (OR) with 95% confidence intervals were used to compare the treatment effects for categorical outcomes. We employed a fixed-effect model for analyses with low heterogeneity (I2 < 25%) and a random-effects model for analyses with higher heterogeneity.

RESULTS

A total of 1519 patients were included, with 50% (n = 760) receiving intensive BP control (systolic BP < 140 mmHg). Functional disability or death at 90 days was significantly higher in the intensive group (54.9%) compared to the conventional treatment group (44.1%) (OR = 1.51; 95% Confidence Interval [CI]: 1.15-1.96; p = 0.003; I2 = 29%). Severe functional disability (mRS 3-5) was significantly higher in the intensive group (30.6% vs. 43.5%, OR = 1.75; 95%CI = 1.36-2.25; p < 0.0001; I2 = 0%). There was no difference in symptomatic intracranial hemorrhage (OR = 1.13; 95%CI = 0.76-1.67) or mortality (OR = 1.22; 95%CI = 0.9-1.64).

CONCLUSIONS

Intensive BP control is harmful in patients who underwent EVT for AIS and achieved successful reperfusion. It yields higher rates of functional dependence, with no differences in mortality or symptomatic intracranial hemorrhage.

Circle of Willis integrity in acute middle cerebral artery occlusion: does the posterior communicating artery matter?

BACKGROUND

Collateral circulation is an important determinant of outcome in people with acute ischemic stroke due to large vessel occlusion (LVO).

OBJECTIVE

To explore the impact of the circle of Willis (CW) anatomical characteristics ipsilateral to the occlusion site, particularly the posterior communicating artery (PComA) and the A1-portion of the anterior cerebral artery (A1-ACA), on stroke outcomes in a cohort of patients with LVO and middle cerebral artery (MCA) occlusion, undergoing endovascular thrombectomy (EVT).

METHODS

This is a retrospective cohort study performed in a comprehensive tertiary stroke center. The study population consisted of consecutive patients with LVO with proximal MCA occlusion (M1) between June 2016 and April 2021, undergoing EVT. Demographic, clinical, and imaging information was extracted from patient files. Patency and diameters of ipsilateral A1-ACA and PComA were manually measured on admission CT angiography images in the core laboratory.

RESULTS

One hundred and five patients with LVO comprised the study cohort, mean age 72.3 years, 43.8% were male, mean National Institutes of Health Stroke Scale score at admission 15.2. The cohort was grouped according to CW vessel characteristics. On univariate analysis, a well-developed PComA was associated with lower rates of hemorrhagic transformation (1.8% vs 14.3%, P=0.01) and a trend towards lower mortality rates (8.9% vs 20.4%, P=0.08).On multivariable regression analysis a well-developed PComA emerged as an independent predictor for survival (aOR=0.09, 95% CI 0.01 to 0.4 for survival at discharge, P=0.009, aOR=0.22, 95% CI 0.05 to 0.8 for survival at 90 days, P=0.02).

CONCLUSIONS

In a cohort of patients with LVO due to M1 occlusion undergoing EVT, a well-developed PComA was associated with significantly lower hemorrhagic transformation rates, a trend towards better functional outcomes, and independently predicted survival. Larger studies are needed to understand the differential effect of CW collateral conduits on stroke outcome and evaluate the practicality of incorporating such factors in the clinical decision-making process prior to EVT.

Review of Cerebral Collateral Circulation and Insight into Cardiovascular Strategies to Limit Collateral Damage in Ischemic Stroke

Cerebral collateral circulation is a dynamic and adaptive process by which alternative vascular pathways supply perfusion to ischemic brain tissue in the event of an arterial occlusion. This complicated network of blood vessels that acts as a natural bypass plays a pivotal role in stroke pathophysiology and has become a key area of study given its significance in stroke treatment and patient outcomes. In this review, we will study the factors influencing the formation, recruitment, and endurance of collateral vessels; discuss imaging modalities for quantitative and qualitative assessment of this network; explore the role of collaterals in stroke management; and highlight several cardiovascular strategies to minimize damage to collaterals and optimize stroke outcomes.

Arterial transit artifact as a short-term prognostic indicator in acute ischemic stroke

BACKGROUND

Arterial transit artifact (ATA) observed on arterial spin labeling (ASL) was recently suggested to be associated with improved functional outcomes following acute ischemic stroke (AIS). AIS is a heterogeneous disease with diverse pathogenic mechanisms depending on the stroke subtype. This study aimed to investigate the association between ATA and 3-month functional outcomes in AIS patients according to etiology subtypes.

METHODS

Consecutive patients with AIS were included. All patients underwent ASL MRI with postlabeling delay (PLD) of 1.5 and 2.5 s. ATA was assessed from the ASL images of both PLDs. Stroke etiologic subtypes were determined according to the modified TOAST (Trial of ORG 10172 in Acute Stroke Treatment) classification. Short-term functional outcomes were evaluated using the 3-month modified Rankin scale (mRS). Log-binomial regression was applied to analyze the association between ATA and functional outcomes at 3 months after stroke.

RESULTS

Ninety-eight AIS patients (62.73 ± 13.05 years; 68 men) were finally included. ATA was detected in forty-six patients and most frequently seen in the large-artery atherosclerosis (LAA) subtype (35/46). The ATA group exhibited a lower percentage of patients with mRS > 2 compared to the group without ATA (36.5% vs. 19.6%; P < 0.001). ATA was independently associated with better 3-month clinical outcomes (adjusted risk ratio, 0.35[95% CI, 0.16-0.74]) in the multivariate log-binomial regression model. After stratification by TOAST subtypes, a significant association was found between ATA and better outcomes in the LAA subtype (adjusted risk ratio, 0.20[ 95% CI, 0.05-0.72]) but not in cardioembolism and small artery occlusion (SVO) subtype.

CONCLUSION

ATA is associated with better outcomes at 3 months in patients with AIS, especially in the LAA subtype, but this association attenuated in the cardioembolism and SVO subtypes.

Standard Versus Intensive Blood Pressure Control in Acute Ischemic Stroke Patients Successfully Treated With Endovascular Thrombectomy: A Systemic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND PURPOSE

The optimal blood pressure (BP) control after successful endovascular thrombectomy (EVT) in acute ischemic stroke (AIS) with large vessel occlusion (LVO) remains debatable. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) that evaluate the efficacy and safety of standard BP control (with systolic BP ≤180 mm Hg) versus intensive BP control (systolic BP <140 mm Hg) during the 24 hours after successful EVT in AIS with LVO.

METHODS

PubMed, Scopus, the Cochrane Central Register of Controlled Trials, and Embase were searched to identify relevant trials. The crude odds ratio (OR) and 95% confidence interval (CI) were calculated and estimates using random-effects models were pooled. This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO ID: CRD42023450673).

RESULTS

Four RCTs involving 1,559 participants were included. Regarding efficacy outcomes, intensive BP control was associated with a lower likelihood of functional independence (OR: 0.68; 95% CI: 0.51-0.91 for modified Rankin Scale [mRS] ≤2) and walking without assistance (OR: 0.65; 95% CI: 0.53-0.81 for mRS ≤3). For safety outcomes, consistent with the efficacy findings, intensive BP control was significantly associated with severe disability or death (mRS 5 or 6) (OR: 1.34; 95% CI: 1.07-1.69). However, there were no significant differences including all-cause mortality, any intracerebral hemorrhage (ICH), symptomatic ICH, parenchymal hematoma type 2, and stroke recurrence.

CONCLUSION

While all four RCTs were conducted to demonstrate the superiority of intensive BP control over standard BP control, standard BP control may be beneficial for the outcome after EVT for AIS with LVO without increasing adverse safety outcomes. Caution should be needed with the application of intensive BP control during the 24 hours following successful recanalization after EVT.

Postoperative blood glucose increase is associated with futile recanalization in patients with successful thrombectomy: a retrospective study

BACKGROUND

Timely recognition of futile recanalization might enable a prompt response and an improved outcome in post-thrombectomy patients. This study aims to evaluate whether postoperative blood glucose increase (BGI) could act as an indicator of futile recanalization in patients receiving a successful thrombectomy.

METHODS

This is a single-center, retrospective analysis of patients with anterior circulation large-vessel occlusion and successful thrombectomy between February 2019 and June 2022. BGI was defined as a higher level of blood glucose at the first postoperative morning than at admission. Futile recanalization was defined as patients with a modified Rankin Scale score of 3-6 at 90 days after onset. Multivariable binary logistic regression was used to assess the association of BGI with futile recanalization.

RESULTS

A total of 276 patients were enrolled, amongst which 120 patients (43.5%) had BGI. Futile recanalization was more prevalent among patients with BGI compared to those without (70.0 vs. 49.4%, P = 0.001). After adjusting for potential confounders, BGI was associated with a higher likelihood of futile recanalization (adjusted OR: 2.97, 95%CI: 1.50-5.86, P = 0.002). This association was consistently observed regardless of diabetes history, occlusion site, time from symptom onset to groin puncture, or reperfusion status.

CONCLUSION

Our findings support BGI serving as an indicator of futile recanalization in patients with anterior circulation large-vessel occlusion and successful thrombectomy.

Core overestimation of CT perfusion in patients with cardiac insufficiency who had a stroke is mediated by impaired collaterals

BACKGROUND

We hypothesized that left ventricular systolic dysfunction (LVSD) would lead to an ischemic core overestimation in patients with acute ischemic stroke (AIS), and impaired collateral status might partly mediate this effect.

OBJECTIVE

A pixel-based analysis of CT perfusion (CTP) and follow-up CT was undertaken to investigate the optimum CTP thresholds for the ischemic core if overestimation was found.

METHODS

A total of 208 consecutive patients with AIS with large vessel occlusion in the anterior circulation, who received initial CTP evaluation and successful reperfusion, were retrospectively analyzed and divided into an LVSD (left ventricular ejection fraction (LVEF) ratio <50%; n=40) and a normal cardiac function (LVEF≥50%; n=168) group. Ischemic core overestimation was considered when the CTP-derived core was larger than the final infarct volume. We investigated the relationship between cardiac function, probability for core overestimation, and collateral scores using mediation analysis. A pixel-based analysis was undertaken to define the optimum CTP thresholds for ischemic core.

RESULTS

LVSD was independently associated with impaired collaterals (aOR=4.28, 95% CI 2.01 to 9.80, P<0.001) and core overestimation (aOR=2.52, 95% CI 1.07 to 5.72, P=0.030). In mediation analysis, the total effect on core overestimation is composed of the direct effect of LVSD (+17%, P=0.034) and the mediated indirect effect of collateral status (+6%, P=0.020). Collaterals explained 26% of the effect of LVSD on core overestimation. Compared with relative cerebral blood flow (rCBF) thresholds of <35%, <30%, and <20%, a rCBF <25% cut-off point had the highest correlation (r=0.91) and best agreement (mean difference 3.2±7.3 mL) with the final infarct volume to determine the CTP-derived ischemic core in patients with LVSD.

CONCLUSIONS

LVSD increased the possibility of ischemic core overestimation on baseline CTP, partly due to impaired collateral status, and a stricter rCBF threshold should be considered.

Postoperative fibrinogen-to-albumin ratio acting as an indicator of futile recanalization in patients with successful thrombectomy

BACKGROUND

Timely recognition of futile recanalization might enable a prompter response and thus improve outcomes in patients receiving successful thrombectomy. This study aims to evaluate whether postoperative fibrinogen-to-albumin ratio (FAR) could act as an indicator of futile recanalization.

METHODS

This is a single-center, retrospective analysis of patients with acute anterior circulation large-vessel occlusion and successful thrombectomy between May 2019 and June 2022. FAR was defined as postoperative blood levels of fibrinogen divided by those of albumin, and dichotomized into high and low levels based on the Youden index. Futile recanalization was defined as patients achieving a successful recanalization with a modified Rankin Scale score of 3-6 at 90 days. Multivariable logistic regression was used to assess the association of FAR with futile recanalization.

RESULTS

A total of 255 patients were enrolled, amongst which 87 patients (34.1%) had high postoperative FAR. Futile recanalization was more prevalent among patients with high FAR compared to those with low FAR (74.7% vs. 53.0%, p = .001). After adjusting for potential confounders, high postoperative FAR was found to independently correspond with the occurrence of futile recanalization (adjusted OR 2.40, 95%CI 1.18-4.87, p = .015). This association was consistently observed regardless of prior antithrombotic therapy, treatment of intravenous thrombolysis, occlusion site, time from symptom onset to groin puncture, and reperfusion status.

CONCLUSION

Our findings support high postoperative FAR serving as an indicator of futile recanalization in patients with anterior circulation large-vessel occlusion and successful thrombectomy.

Association of blood pressure parameters post mechanical thrombectomy in anemic versus non-anemic patients and clinical outcomes

INTRODUCTION

Higher blood pressure (BP) is considered to be detrimental in patients who undergo mechanical thrombectomy (MT), however, the impact of BP post-MT based on comorbidities like anemia has not been well studied. We aim to determine the association of 24-h post-MT BP parameters with clinical outcomes depending on their anemia status.

METHODS

We conducted a retrospective chart review of patients who underwent MT at a comprehensive stroke center from 1/2015 to 12/2020. Patients were dichotomized into anemic and non-anemic groups based on the World Health Organization's definition of anemia [hemoglobin < 12.0 g/dL in women and < 13.0 g/dL in men]. We performed a multivariable analysis with binary logistic regression with the 24-h post-MT BP parameters as predictors. The outcomes were functional dependence (3-month mRS 3-6), mortality, and an early neurological improvement.

RESULTS

220 patients met the inclusion criteria. 158 (71.82 %) patients had functional dependence at 3-months. In the multivariable analysis, the parameters of a higher mean SBP (132.9 ± 11.94 vs.126.52 ± 13.3; OR, 1.05; 95 % CI, 1.02-1.09; P 0.011), a higher mean MAP (93.35 ± 8.44 vs.89.69 ± 10.03; OR,1.06; 95 % CI, 1.01-1.11; P 0.029) and a higher maximum MAP (115.26 ± 11.73 vs.109.37 ± 12.51; OR,1.05; 95 % CI, 1.01-1.08; P 0.023)were significantly associated with functional dependence in non-anemic patients, while a lower mean DBP (65.53 ± 9.73 vs. 71.94 ± 10.16; OR, 0.92; 95 % CI, 0.86-0.98; P 0.007), lower mean MAP (85.7 ± 8.65 vs. 91.38 ± 10; OR, 0.93; 95 % CI, 0.86-0.99; P 0.02), a lower minimum DBP (49.27 ± 10.51 vs. 55.1 ± 11.23; OR, 0.93; 95 % CI, 0.88-0.99; P 0.019), a lower minimum MAP (68.96 ± 9.54 vs. 74.73 ± 10.47; OR, 0.93; 95 % CI, 0.87-0.99; P 0.023) were significantly associated with mortality in patients with anemia, and a lower minimum DBP (54.75 ± 10.42 vs. 59.69 ± 8.87; OR, 0.95; 95 % CI, 0.91-0.99; P 0.012) and a lower minimum MAP (71.92 ± 14.7 vs.75.67 ± 14.17; OR, 0.97; 95 % CI, 0.94-0.99; P 0.047) were significantly associated with an early neurological improvement in non-anemic patients. For patients with anemia, there was no association between 24-hour BP Parameters post-MT and functional dependence and early neurological improvement, and between 24-hour BP Parameters post-MT and mortality in non-anemic patients.

CONCLUSION

In our study, higher BP parameters were associated with worse outcomes in patients without anemia, however, this effect was not found in patients with anemia. Certain lower BP parameters were associated with higher 3-month mortality in anemic patients; however, this effect was not found in non-anemic patients. Higher BP post-MT can potentially promote perfusion and thus is not associated with worse outcomes in anemic patients post-MT, whereas in non-anemic patients it may potentially lead to reperfusion injury While our study is limited because of size and its retrospective nature, the findings suggest that an individualized approach to tailor the target BP post-MT to a patient's risk factor profile and associated co-morbid conditions to achieve optimization of medical care post-MT and associated co-morbid conditions to achieve optimization of medical care post-MT.

Association between left atrial enlargement and poor cerebral collaterals in large vessel occlusion

OBJECTIVES

Left atrial enlargement (LAE) is a known risk factor for atrial fibrillation, a common cause of large vessel occlusion (LVO) leading to ischemic stroke. While robust cerebral collaterals protect penumbral tissue from infarction, the effect of structural heart disease on cerebral collaterals remains uncertain. This study aims to investigate the association between LAE and cerebral collaterals in patients with acute LVO stroke.

MATERIALS AND METHODS

We conducted a retrospective study of consecutive patients with middle cerebral and/or internal carotid LVO who underwent endovascular thrombectomy (EVT) between 2012 to 2020. Consecutive patients with echocardiography and computed tomography angiography (CTA) of the head were included. Multivariate logistic regression analysis was performed to evaluate the relationship between LAE and poor cerebral collaterals, adjusting for demographics (age, sex, race) and vascular risk factors (hypertension, diabetes and smoking).

RESULTS

The study included 235 patients with mean age of 69±15 years and an initial mean National Institutes of Health Stroke Scale score of 18. Of these, 89 (37.9 %) had LAE, and 105 (44.7 %) had poor collaterals. Patients with LAE were more likely to have poor collaterals compared to those without LAE (58.4 % vs 36.3 %, P = 0.001). LAE was independently associated with higher odds of poor collaterals (odds ratio, 2.47; P = 0.001), even after adjusting for covariables (odds ratio 1.84, P = 0.048).

CONCLUSIONS

Our study demonstrated a significant association between LAE and poor cerebral collaterals in patients with LVO stroke undergoing EVT. Further research is warranted to explore potential shared mechanisms, such as endothelial dysfunction, underlying this heart-brain association.

Collateral Status Modification of the Association Between Blood Pressure Variation Within 72 Hours After Endovascular Treatment and Clinical Outcome in Acute Ischemic Stroke: A Retrospective Cohort Study

Background

Blood pressure variation and collateral status have been reported to be associated with clinical outcome in patients with acute ischemic stroke who received endovascular treatment; however, the relationship between blood pressure variation within 72 hours after EVT and clinical outcome in different collateral status remains unclear.

Methods

Acute ischemic stroke patients due to large vessel occlusion with EVT were retrospectively enrolled. We classified participants into poor collateral (ASITN/SIR grade <2) and good collateral subgroups (ASITN/SIR grade ≥2). The primary outcome was unfavorable neurological outcome defined as a 3-month modified Rankin Scale (mRS) score ≥2. The interactive effect was tested to determine the influence of collateral status on the association between BP variation and clinical outcome.

Results

A total of 545 patients were included. The poor collateral subgroup was detected in 198 patients with an average age of 70.2 years. The association between BP variation and primary outcome did not differ under different collateral status (P for interaction >0.05). However, the association between the mean and coefficient of variation (CV) values of DBP and 3-month mortality was significantly discrepant under different collateral status (P for interaction <0.05). In the good collateral subgroup, higher mean DBP was associated with a lower risk of 3-month mortality (OR 0.95, 95% CI 0.91-1, P = 0.033) compared with the poor subgroup (OR 1.04, 95% CI 0.97-1.1, P = 0.286). In addition, a higher CV of DBP was associated with a higher risk of 3-month mortality (OR 1.24, 95% CI 1.13-1.36, P < 0.01) compared with poor status (OR 1.08, 95% CI 0.94-1.23, P=0.275).

Conclusion

For patients who received EVT with good collateral status, increased CV of DBP was significantly associated with higher 3-month mortality, while higher mean DBP within 72 h after EVT was associated with a decrease in 3-month mortality.

Impact of volemia at admission on the effect of collateral status on functional outcomes in patients undergoing endovascular thrombectomy

BACKGROUND AND PURPOSE

Having good collaterals is associated with better clinical outcomes in patients undergoing endovascular thrombectomy. This study aims to evaluate whether the effect of collateral status on functional outcomes is modified by volemia at admission.

METHODS

This is a single-center, retrospective analysis of patients who had acute proximal anterior circulation occlusion and underwent endovascular thrombectomy between January 2019 and June 2022. Volemia at admission, evaluated by blood urea nitrogen-to-creatinine ratio, was used to dichotomize patients into dehydrated and hydrated groups. The primary outcome was functional independence (90-day modified Rankin Scale score = 0-2). Secondary outcomes were the rates of successful reperfusion, 24-h symptomatic intracranial hemorrhage, and 90-day all-cause mortality. Multivariable logistic regression analysis was used to assess the interaction between collateral status and volemia at admission on outcomes.

RESULTS

A total of 290 patients were enrolled, among whom having good collaterals was associated with functional independence (adjusted odds ratio [OR] = 2.71, 95% confidence interval [CI] = 1.41-5.22, p = 0.003). Having good collaterals benefited dehydrated patients (adjusted OR = 3.33, 95% CI = 1.45-7.63, p = 0.004) but not hydrated patients (adjusted OR = 2.21, 95% CI = 0.73-6.68, p = 0.161). However, an interaction between collaterals and volemia at admission on functional independence was not observed (p = 0.319). The rates of successful reperfusion, symptomatic intracerebral hemorrhage, and all-cause mortality were similar between those with good and poor collaterals in both dehydrated and hydrated patients.

CONCLUSIONS

The effect of collateral status on the functional independence of patients undergoing thrombectomy is not modified by volemia at admission.

Association between blood pressure and endovascular treatment outcomes differs by baseline perfusion and reperfusion status

We hypothesized that the association between BP and endovascular treatment (EVT) outcomes would differ by baseline perfusion and recanalization status. We identified 388 ICA or M1 occlusion patients who underwent EVT ≤ 24 h from onset with successful recanalization (TICI ≥ 2b). BP was measured at 5-min intervals from arrival and during the procedure. Systolic BPs (SBP) were summarized as dropmax (the maximal decrease over two consecutive measurements), incmax (the maximal increase), mean, coefficient of variation (cv), and standard deviation. Adequate baseline perfusion was defined as hypoperfusion intensity ratio (HIR) ≤ 0.5; infarct proportion as the volume ratio of final infarcts within the Tmax > 6 s region. In the adequate perfusion group, infarct proportion was closely associated with SBPdropmax (β ± SE (P-value); 1.22 ± 0.48, (< 0.01)), SBPincmax (1.12 ± 0.33, (< 0.01)), SBPcv (0.61 ± 0.15 (< 0.01)), SBPsd (0.66 ± 0.08 (< 0.01)), and SBPmean (0.71 ± 0.37 (0.053) before recanalization. The associations remained significant only in SBPdropmax, SBPincmax, and SBPmean after recanalization. SBPincmax, SBPcv and SBPsd showed significant associations with modified Rankin Scale score at 3 months in the pre-recanalization period. In the poor perfusion group, none of the SBP indices was associated with any stroke outcomes regardless of recanalization status. BP may show differential associations with stroke outcomes by the recanalization and baseline perfusion status.

Influence of the integrity of circle of Willis on asymptomatic or mild patients with first diagnosed chronic internal carotid artery occlusion

BACKGROUND

In order to identify individuals with chronic internal carotid artery occlusion (CICAO), it is essential to understand the integrity of the circle of Willis (CoW). This understanding is important as it may determine the potential benefits of active medical and endovascular treatments.

PURPOSE

The objective of this study is to assess whether diminished integrity of the CoW can serve as a useful marker for identifying individuals with more severe impairment in cerebral blood perfusion and a higher incidence of cerebral infarction among asymptomatic or mildly affected patients with CICAO.

MATERIALS AND METHODS

We conducted a retrospective review of asymptomatic or mildly affected patients with newly diagnosed CICAO who did not receive reperfusion therapies. The categorization of patients into good or poor integrity groups was based on the assessment of CoW integrity using CTA. We evaluated the volume and value of prolonged time to peak (TTP) in both groups, as well as the occurrence of new cerebral infarctions. Our analysis involved multivariate regression and receiver operating characteristic (ROC) analysis.

RESULTS

Hemodynamic abnormalities characterized by prolonged TTP were observed in the affected side's blood supply region in all 38 patients. There was a notable difference in the volume and value of prolonged TTP between the two groups (P < 0.001). Correlation analyses based on CTP and CTA parameters revealed a negative relationship between CoW scores and both the abnormal volume (r = -0.624, P = 0.000) and value (r = -0.589, P = 0.000) of prolonged TTP. Upon multivariable adjustment, the independent predictors for new cerebral infarction and higher volume of prolonged TTP were solely the CoW status, with respective estimates of (b = 6.05; 95% confidence interval [CI]: 1.619, 22.619; P = 0.007) and (b = 35.486; 95% CI: 4.697, 268.088; P = 0.001).

CONCLUSION

Assessing the integrity of the CoW is crucial in evaluating abnormal perfusion in asymptomatic or mildly affected individuals who are newly diagnosed with CICAO and have not undergone reperfusion therapy.

Predicting DWI-FLAIR mismatch on NCCT: the role of artificial intelligence in hyperacute decision making

Background

The presence of diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) mismatch was used to determine eligibility for intravenous thrombolysis in clinical trials. However, due to the restricted availability of MRI and the ambiguity of image assessment, it is not widely implemented in clinical practice.

Methods

A total of 222 acute ischemic stroke patients underwent non-contrast computed tomography (NCCT), DWI, and FLAIR within 1 h of one another. Human experts manually segmented ischemic lesions on DWI and FLAIR images and independently graded the presence of DWI-FLAIR mismatch. Deep learning (DL) models based on the nnU-net architecture were developed to predict ischemic lesions visible on DWI and FLAIR images using NCCT images. Inexperienced neurologists evaluated the DWI-FLAIR mismatch on NCCT images without and with the model's results.

Results

The mean age of included subjects was 71.8 ± 12.8  years, 123 (55%) were male, and the baseline NIHSS score was a median of 11 [IQR, 6-18]. All images were taken in the following order: NCCT - DWI - FLAIR, starting after a median of 139 [81-326] min after the time of the last known well. Intravenous thrombolysis was administered in 120 patients (54%) after NCCT. The DL model's prediction on NCCT images revealed a Dice coefficient and volume correlation of 39.1% and 0.76 for DWI lesions and 18.9% and 0.61 for FLAIR lesions. In the subgroup with 15  mL or greater lesion volume, the evaluation of DWI-FLAIR mismatch from NCCT by inexperienced neurologists improved in accuracy (from 0.537 to 0.610) and AUC-ROC (from 0.493 to 0.613).

Conclusion

The DWI-FLAIR mismatch may be reckoned using NCCT images through advanced artificial intelligence techniques.

Effect of blood pressure on the prognosis of acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization

PURPOSE

To explore the effect of blood pressure on the prognosis of acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization.

METHODS

Acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization were retrospectively collected. All patients were divided into the functional independent group and non-functional independent group, death group and non-death group based on the 90-day mRS score. Logistic regression was applied to analyze the relationship between the highest systolic blood pressure, the average systolic blood pressure, the lowest systolic blood pressure, the highest diastolic blood pressure, the average diastolic blood pressure, the lowest diastolic blood pressure in the first 24 h after admission and the functional prognosis as well as the complications after 90 days. The independent impact factors selected from regression analysis were used to investigate the blood pressure with prognostic value by receiver operating characteristic curve (ROC).

RESULTS

A total of 70 patients were recruited in this study. Among them, 39 cases (55.71%) were male and 31 cases (44.29%) were female, with a mean age of 61.83 ± 15.24 years old. 15 cases (21.43%) had a favorable 90-day outcome, and the other 55 cases (78.57%) had a higher mRS Score. After a 90-day follow-up, univariate analysis showed that hypertension and hyperlipidemia, highest systolic blood pressure, mean systolic blood pressure and NIHSS score were statistically significant in two groups with or without functional independence, while the NIHSS score at admission, systolic blood pressure at admission, average systolic blood pressure, highest systolic blood pressure and diastolic blood pressure were statistically significant in patients with death outcomes (P < 0.05). Multivariate regression analysis suggested that the highest systolic blood pressure was statistically significant (P < 0.05), the further ROC curve results showed the cut-off value of the highest systolic blood pressure was 180.5 mmHg, with a sensitivity of 82.35% and a specificity of 81.13%. The highest Youden's index was 0.6348.

CONCLUSION

For acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization, the appropriate reduction of blood pressure within 24 h after admission may have a positive effect on the clinical prognosis. The 90-day mortality of acute ischemic stroke patients without revascularization was independently related to the highest systolic blood pressure. The risk of death was increased when the highest systolic blood pressure was greater than 180.5 mmHg.

Relevance of Carotid Reocclusion in Tandem Lesions

AIMS

Carotid reocclusion (CRO) after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) due to tandem lesion (TL) or isolated internal carotid occlusion (ICO) is associated with worse clinical outcomes. Our aim was to analyze the predictors and clinical impact of CRO.

METHODS

A retrospective single-center analysis of all patients with anterior circulation strokes who underwent MT prospectively included in a registry between 2017 and 2020 was performed. ICO and TL as stroke causes were included. Stent deployment was left to the discretion of the interventionist. All patients received at least intravenous aspirin during MT. CRO was assessed using ultrasound within the first 24 h after MT. Efficacy and safety of stenting were assessed.

RESULTS

Among 1304 AIS cases, 218 (16.7%) were related to TL or ICO. Of them, 5% (n=11) were associated with internal CRO 24 h after the endovascular procedure. After adjusting per confounders, multivariate analysis showed that the independent variables associated with CRO were the TICI recanalization grade [TICI 2b-3; OR 0.1, 95% confidence interval (CI) 0.01-0.89, p=0.040], pial collateral circulation presence (OR 0.09, 95% CI 0.02-0.45, p=0.03), stent deployment during MT (OR 0.17, 95% CI 0.03-0.84, p=0.030), and general anesthesia use (OR 2.92, 95% CI 1.13-7.90, p=0.034). CRO showed a trend toward worst outcomes (modified Rankin scale 3-6) at 3 months (OR 3.4, 95% CI 0.96-12, p=0.057). After multivariate analysis, variables independently associated with worse outcomes at 90 days were intrastent platelet aggregation phenomena during endovascular therapy, admission National Institute of Health Stroke Scale, and age. Conversely, intravenous thrombolysis and TICI 2b-3 recanalization grade were identified as independent predictors of good outcomes at 90 days.

CONCLUSIONS

CRO has a relevant clinical impact in our study, associating lower rates of good functional outcomes at 3 months. Independent factors of CRO were the recanalization degree, presence of pial collateral circulation, use of a stent as a protective factor, and use of general anesthesia during thrombectomy.

Automated scoring of collaterals, blood pressure, and clinical outcome after endovascular treatment in patients with acute ischemic stroke and large-vessel occlusion

Introduction

We aimed to determine whether the degree of collateral circulation is associated with blood pressure at admission in acute ischemic stroke patients treated with endovascular treatment and to determine its prognostic value.

Methods

We evaluated patients with anterior large vessel occlusion treated with endovascular treatment in a single-center prospective registry. We collected clinical and radiological data. Automated and validated software (Brainomix Ltd., Oxford, UK) was used to generate the collateral score (CS) from the baseline single-phase CT angiography: 0, filling of ≤10% of the occluded MCA territory; 1, 11–50%; 2, 51–90%; 3, >90%. When dichotomized, we considered that CS was good (CS = 2–3), or poor (CS = 0–1). We performed bivariate and multivariable ordinal logistic regression analysis to predict CS categories in our population. The secondary outcome was to determine the influence of automated CS on functional outcome at 3 months. We defined favorable functional outcomes as mRS 0–2 at 3 months.

Results

We included 101 patients with a mean age of 72.1 ± 13.1 years and 57 (56.4%) of them were women. We classified patients into 4 groups according to the CS: 7 patients (6.9%) as CS = 0, 15 (14.9%) as CS = 1, 43 (42.6%) as CS = 2 and 36 (35.6%) as CS = 3. Admission systolic blood pressure [aOR per 10 mmHg increase 0.79 (95% CI 0.68–0.92)] and higher baseline NIHSS [aOR 0.90 (95% CI, 0.84–0.96)] were associated with a worse CS. The OR of improving 1 point on the 3-month mRS was 1.63 (95% CI, 1.10–2.44) favoring a better CS (p = 0.016).

Conclusion

In acute ischemic stroke patients with anterior large vessel occlusion treated with endovascular treatment, admission systolic blood pressure was inversely associated with the automated scoring of CS on baseline CT angiography. Moreover, a good CS was associated with a favorable outcome.

Effectiveness and safety of EVT in patients with acute LVO and low NIHSS

Background and purpose

There is much uncertainty in endovascular treatment (EVT) decisions in patients with acute large vessel occlusion (LVO) and mild neurological deficits.

Methods

From a prospective, nationwide stroke registry, all patients with LVO and baseline NIHSS <6 presenting within 24 h from the time last known well (LKW) were included. Early neurological deterioration (END) developed before EVT was prospectively collected as an increasing total NIHSS score ≥2 or any worsening of the NIHSS consciousness or motor subscores during hospitalization not related to EVT. Significant hemorrhage was defined as PH2 hemorrhagic transformation or hemorrhage at a remote site. The modified Rankin Scale (mRS) was prospectively collected at 3 months.

Results

Among 1,083 patients, 149 (14%) patients received EVT after a median of 5.9 [3.6-12.3] h after LKW. In propensity score-matched analyses, EVT was not associated with mRS 0-1 (matched OR 0.99 [0.63-1.54]) but increased the risk of a significant hemorrhage (matched OR, 4.51 [1.59-12.80]). Extraneous END occurred in 207 (19%) patients after a median of 24.5 h [IQR, 13.5-41.9 h] after LKW (incidence rate, 1.41 [95% CI, 1.23-1.62] per 100 person-hours). END unrelated to EVT showed a tendency to modify the effectiveness of EVT (P-for-interaction, 0.08), which decreased the odds of having mRS 0-1 in mild LVO patients without END (adjusted OR, 0.63 [0.40-0.99]).

Conclusions

The use of EVT in patients with acute LVO and low NIHSS scores may require the assessment of individual risks of early deterioration, hemorrhagic complications and expected benefit.