Leukoaraiosis and collateral blood flow in stroke patients with anterior circulation large vessel occlusion

Impact of leukoaraiosis on the infarct growth rate and clinical outcome in acute large vessel occlusion stroke after endovascular thrombectomy

INTRODUCTION

As a marker of chronic cerebral small vessel disease, leukoaraiosis (LA) was reported to impact the recruitment of collaterals in acute ischemic stroke (AIS). We intended to explore the impact of LA on the infarct growth rate (IGR) and clinical outcome by impaired collateral development in AIS patients with large vessel occlusion (LVO) who underwent endovascular thrombectomy (EVT).

PATIENTS AND METHODS

Two hundred thirty-six AIS patients who underwent EVT were retrospectively reviewed. The severity of LA was graded using the Fazekas scale with non-contrast CT. IGR was calculated by the acute core volume on CT perfusion divided by the time from stroke onset to imaging. The collateral status after LVO was assessed using the ASITN/SIR collateral scale. The clinical outcomes after EVT were evaluated using a modified Rankin Scale (mRS). The Alberta stroke program early CT score (ASPECTS), the National Institutes of Health Stroke Scale (NIHSS) score at admission, and the modified treatment in cerebral infarction (mTICI) score after EVT were also included. Correlations between those factors were analyzed.

RESULTS

Patients with severe LA had significantly larger core volume on CTP (p = 0.022) and lower collateral grade (p < 0.001). Faster IGR was significantly associated with higher LA severity (adjusted odds ratio [aOR]: 1.53; 95% CI: 1.02-2.33; p = 0.046), higher NIHSS (aOR: 1.04; 95% CI: 1.00-1.09; p = 0.032) and impaired collaterals (aOR: 2.26; 95% CI: 1.27-4.03; p = 0.005). In mediation analysis, collaterals explained 33% of the effect of LA on fast IGR. There was correlation between the severity of LA and mRS (p = 0.007).

DISCUSSION AND CONCLUSION

The increasing severity of LA is associated with impaired collateral status and fast infarct growth. These findings suggest that LA may become a predictive imaging biomarker for the likelihood of progression of tissue injury and clinical outcome after EVT in acute large vessel occlusion stroke.

Effect of leukoaraiosis on collateral circulation in acute ischemic stroke treated with endovascular therapy: a meta-analysis

BACKGROUND AND OBJECTIVE

The recruitment of collateral circulation correlates with a balance of the microvasculature. Uncertainty remains to be made about the association of leukoaraiosis with leptomeningeal collaterals. To explore the effect of leukoaraiosis on leptomeningeal collaterals in patients treated with endovascular therapy.

METHODS

Observational studies exploring the correlation between leukoaraiosis and leptomeningeal collaterals in large vessel occlusion treated with endovascular therapy were searched from PubMed, EMBASE, and Cochrane Libraries databases. Two independent reviewers retrieved eligible literature, extracted purpose-related data, and utilized the Newcastle-Ottawa Scale to evaluate the risk of bias. A Mantel-Haenszel method was used to calculate the odds ratio (OR). Meta-regression and subgroup analyses were conducted to clarify heterogeneity.

RESULTS

Data from 10 studies with 1606 patients were extracted for pooled analysis. Compared to non-severe leukoaraiosis, patients with severe leukoaraiosis showed significant relevance to poor leptomeningeal collaterals (OR, 2.13; 95% confidence interval [1.27-3.57]; P = 0.004). Meta-regression indicated that sample size (coefficient = -0.007299, P = 0.035) and the number of female patients (coefficient = -0.0174709, P = 0.020) were sources of heterogeneity. Furthermore, all of the countries (USA versus France versus China, Q = 3.67, P = 0.159), various assessment scales of leukoaraiosis (the Fazekas scale versus Non-Fazekas scales, Q = 0.77, P = 0.379), and different imaging methods of leukoaraiosis (computed tomography versus magnetic resonance imaging, Q = 2.12, P = 0.146) and leptomeningeal collaterals (computed tomography angiography versus digital subtraction angiography, Q = 1.21, P = 0.271) showed no contribution to the effect size.

CONCLUSION

Severe leukoaraiosis is associated with poor leptomeningeal collaterals in patients treated with endovascular therapy. Further studies may focus on whether the finding applies to different stroke subtypes.

Leukoaraiosis severity is related to increased risk of early neurological deterioration in acute ischemic stroke: a retrospective observational study

OBJECTIVES

The relationship between leukoaraiosis and early neurological deterioration in acute cerebral infarction patients remains controversial. We tried to determine whether an association existed between leukoaraiosis and early neurological deterioration in patients with acute ischemic stroke.

MATERIALS AND METHODS

We retrospectively enrolled acute cerebral infarction patients admitted to our our department within 4.5-72.0 h of symptom onset between January 2016 and March 2022. On the basis of the van Swieten scale, leukoaraiosis was evaluated as supratentorial white matter hypoattenuation on admission head CT and graded as 0 (absent), 1 (mild), 2 (moderate) and 3-4 (severe). Early neurological deterioration was defined as an increase in the National Institute of Health Stroke Scale score by >  = 2 points in the total score, or >  = 1 point in motor power within the first seven days after admission.

RESULTS

Among 736 patients, 522 (70.9%) patients had leukoaraiosis, and of these, 332 (63.6%) had mild leukoaraiosis, 41 (7.9%) had moderate leukoaraiosis, and 149 (28.5%) had severe leukoaraiosis. 118 (16.0%) patients experienced early neurological deterioration: 20 of the 214 (9.5%) patients without leukoaraiosis and 98 of the 522 (18.8%) patients with leukoaraiosis. In multiple regression analysis, we found van Swieten scale predicted early neurological deterioration independently (OR = 1.570; 95% CI: 1.226-2.012).

CONCLUSIONS

Leukoaraiosis is common in acute cerebral infarction patients and leukoaraiosis severity is related to increased risk of early neurological deterioration in the patients.

Impact of leukoaraiosis or blood pressure on clinical outcome, mortality and symptomatic intracerebral hemorrhage after mechanical thrombectomy in acute ischemic stroke

We aimed to study the impact of leukoaraiosis (LA) and blood pressure (BP) on clinical outcome, mortality and symptomatic intracerebral hemorrhage (sICH) in acute ischemic stroke (AIS) patients treated with mechanical thrombectomy (MT). We analyzed data retrospectively from 521 patients with anterior large vessel occlusion treated with MT. LA was dichotomized in 0-2 (absent-to-moderate) versus 3-4 (moderate-to-severe) according to the van Swieten scale. Various systolic (SBP) and diastolic (DBP) BP parameters during the first 24 h were collected. Multivariable logistic regressions were performed to identify predictors of a poor 90-day outcome, mortality and sICH. LA was significantly associated with poor outcome (OR 3.2; p < 0.001) and mortality (OR 3.19; p = 0.008), but not sICH (p = 0.19). Higher maximum SBP was significantly associated with poor outcome (OR per 10 mmHg increase = 1.21; p = 0.009) and lower mean DBP was a predictor of mortality (OR per 10 mmHg increase = 0.53; p < 0.001). In the univariate analysis high SBP variability was associated with poor outcome, mortality and sICH, but not in the multivariate model. There was no association between BP and sICH. Severity of LA, SBP variability, high maximum SBP and low DBP are associated with either poor outcome or mortality in AIS patients undergoing MT. However, neither LA nor BP were associated with sICH in our cohort. Thus, mechanisms of the negative impact on outcome remain unclear. Further studies on impact of BP course and its mechanisms and interventions are needed to improve outcome in patients undergoing MT.

Leukoaraiosis Distribution and Cerebral Collaterals: A Systematic Review and Meta-Analysis

Background and Objective

Microvascular failure might result in the collapse of cerebral collaterals. However, controversy remains regarding the role of leukoaraiosis (LA) in collateral recruitment. We, therefore, performed a systematic review and meta-analysis of the association between LA and cerebral collaterals.

Methods

Ovid Medline, PubMed, Embase, Web of Science, and three Chinese databases were searched from inception to August 2021. Two types of cerebral collaterals, including Circle of Willis (CoW) and leptomeningeal collaterals (LC), were investigated separately. Random effect models were used to calculate the pooled odds ratio (OR). Meta-regression and subgroup analyses were performed to explore the potential sources of heterogeneity.

Results

From 14 studies (n = 2,451) that fulfilled our inclusion criteria, data from 13 could be pooled for analysis. Overall, there was a significant association between severe LA and incomplete CoW (pooled OR 1.66, 95% CI 1.18–2.32, p = 0.003), with low heterogeneity (I² = 5.9%). This association remained significant in deep LA (pooled OR 1.48, 95% CI 1.04–2.11, p = 0.029, I² = 0), but not periventricular LA. Similarly, there was a significant association between LA and LC (pooled OR 1.73, 95% CI 1.03–2.90, p = 0.037), but with high heterogeneity (I² = 67.2%). Meta-regression indicated a negative association of sample size with the effect sizes (p = 0.029). In addition, most of the studies (7/9) included into the analysis of the relationship of severe LA with poor LC enrolled subjects with large vessel occlusion stroke, and this relationship remained significant when pooling the seven studies, but with high heterogeneity.

Conclusion

Severe LA is associated with a higher prevalence of poor collaterals. This association is robust for CoW but weak for LC. Further studies are required to explore the underlying mechanisms.

Small vessel disease and collaterals in ischemic stroke patients treated with thrombectomy

BACKGROUND AND PURPOSE

To determine the influence of the cerebral small vessel disease (SVD) burden on collateral recruitment in patients treated with mechanical thrombectomy (MT) for anterior circulation acute ischemic stroke (AIS).

METHODS

Patients with AIS due to large vessel occlusion (LVO) from the Thrombectomie des Artères Cérébrales (THRACE) trial and prospective cohorts from 2 academic comprehensive stroke centers treated with MT were pooled and retrospectively analyzed. Collaterals' adequacy was assessed using the American Society of Interventional and Therapeutic Radiology/Society of Interventional Radiology (ASITN/SIR) score on initial digital subtraction angiography and dichotomized as good (3,4) versus poor (0-2) collaterals. The SVD burden was rated with the global SVD score on MRI. Multivariable logistic regression analyses were used to determine relationships between SVD and ASITN/SIR scores.

RESULTS

A total of 312 participants were included (53.2% males, mean age 67.8 ± 14.9 years). Two hundred and seven patients had poor collaterals (66.4%), and 133 (42.6%) presented with any SVD signature. In multivariable analysis, patients demonstrated worse leptomeningeal collaterality with increasing SVD burden before and after adjustment for SVD risk factors (adjusted odds ratio [aOR] 0.69; 95%CI [0.52-0.89] and aOR 0.66; 95%CI [0.5-0.88], respectively). Using individual SVD markers, poor collaterals were significantly associated with the presence of lacunes (aOR 0.40, 95% CI [0.20-0.79]).

CONCLUSION

Our study provides evidence that in patients with AIS due to LVO treated with MT, the burden of SVD assessed by pre-treatment MRI is associated with poorer recruitment of leptomeningeal collaterals.

Pre-stroke Physical Activity and Cerebral Collateral Circulation in Ischemic Stroke: A Potential Therapeutic Relationship?

Favorable cerebral collateral circulation contributes to hindering penumbral tissue from progressing to infarction and is associated with positive clinical outcomes after stroke. Given its clinical importance, improving cerebral collateral circulation is considered a therapeutic target to reduce burden after stroke. We provide a hypothesis-generating discussion on the potential association between pre-stroke physical activity and cerebral collateral circulation in ischemic stroke. The recruitment of cerebral collaterals in acute ischemic stroke may depend on anatomical variations, capacity of collateral vessels to vasodilate, and individual risk factors. Physical activity is associated with improved cerebral endothelial and vascular function related to vasodilation and angiogenic adaptations, and risk reduction in individual risk factors. More research is needed to understand association between cerebral collateral circulation and physical activity. A presentation of different methodological considerations for measuring cerebral collateral circulation and pre-stroke physical activity in the context of acute ischemic stroke is included. Opportunities for future research into cerebral collateral circulation, physical activity, and stroke recovery is presented.

Leukoaraiosis severity and post-reperfusion outcomes in acute ischaemic stroke: A meta-analysis

OBJECTIVES

Severity of leukoaraiosis may mediate outcomes after reperfusion therapy in acute ischaemic stroke (AIS) patients. However, the level of the association remains poorly understood. We performed a meta-analysis to investigate the impact of leukoaraiosis severity on functional outcome, survival, haemorrhagic complications, and procedural success in AIS patients treated with intravenous thrombolysis and/or endovascular thrombectomy.

MATERIALS AND METHODS

PubMed, EMBASE and the Cochrane library were searched for studies on leukoaraiosis in AIS receiving reperfusion therapy. A random-effects meta-analysis was conducted for post-reperfusion outcomes in AIS patients with absent-to-mild leukoaraiosis and moderate-to-severe leukoaraiosis. The strength of association between moderate-to-severe leukoaraiosis and poor outcomes was quantified using odds ratios (OR).

RESULTS

A total of 15 eligible studies involving 6460 patients (1451 with moderate-to-severe leukoaraiosis and 5009 with absent-to-mild leukoaraiosis) were included in the meta-analysis. Moderate-to-severe leukoaraiosis was significantly associated with poor 90-day functional outcome (OR 3.16; 95% confidence interval (CI) 2.69-3.72; p < .0001), 90-day mortality (OR 3.11; 95% CI 2.27-4.26; p < .0001) and increased risk of symptomatic intracerebral haemorrhage (OR 1.69; 95% CI 1.24-2.32; p = .001) after reperfusion therapy. Overall, no significant association of leukoaraiosis severity with haemorrhagic transformation (HT) and angiographic recanalization status were observed. However, subgroup analysis revealed a significant association of WML severity with HT in patients receiving EVT.

CONCLUSION

Leukoaraiosis is a useful prognostic biomarker in AIS. Patients with moderate-to-severe leukoaraiosis on baseline imaging are likely to have worse clinical and safety outcomes after reperfusion therapy.

Influence of Pre-Existing Cerebral Small Vessel Disease on the Outcome of Acute Cardioembolic Stroke: A Retrospective Study

PURPOSE

This study was to explore the role of pre-existing small vessel disease (SVD) on the 3-month outcomes of acute cardioembolic stroke (CES) patients.

PATIENTS AND METHODS

Data of 189 consecutive acute CES patients at a single center were retrospectively enrolled. SVD imaging markers of lacunes, white matter hyperintensities (WMH) and enlarged perivascular spaces (EPVS) were evaluated and their total burden score (0-3 points) was calculated. Patients were divided into the good functional outcome group (modified Rankin scale, mRS ≤ 2) and the poor functional outcome group (mRS ≥ 3) at 3 months after stroke onset. The effect of each single SVD marker and its total burden score on the outcome was identified using binary logistic regression.

RESULTS

Overall, 100 (52.9%), 52 (27.1%), 28 (14.8%) and 9 (4.8%) patients had 0, 1, 2 and 3 SVD imaging markers. Patients with a total SVD burden score of 2 and 3 were significantly older and had higher baseline National Institutes of Health Stroke Scale (NIHSS) score than those with a score of 0 and 1 (P<0.01). Forty-seven (24.9%) patients had a poor outcome. Patients in the poor outcome group had significantly higher baseline NIHSS score, increased incidence of stroke associated pneumonia, and heavier burden of lacunes, WMH and EPVS, and thus had elevated total SVD burden score than those in good outcome group (P<0.05). After adjusting for potential confounders, the WMH (odds ratio [OR] = 2.6777, 95% confidence interval [CI] = 1.052-6.812, P = 0.039) and the total SVD burden score (OR = 1.717, 95% CI = 1.072-2.749, P = 0.024) were, respectively, independent risk factors for a poor outcome.

CONCLUSION

The pre-existing SVD may be associated with the 3-month prognosis of CES.

Reduced Leukoaraiosis, Noncardiac Embolic Stroke Etiology, and Shorter Thrombus Length Indicate Good Leptomeningeal Collateral Flow in Embolic Large-Vessel Occlusion

BACKGROUND AND PURPOSE

Acute leptomeningeal collateral flow is vital for maintaining perfusion to penumbral tissue in acute ischemic stroke caused by large-vessel occlusion. In this study, we aimed to investigate the clinically available indicators of leptomeningeal collateral variability in embolic large-vessel occlusion.

MATERIALS AND METHODS

Among prospectively registered consecutive patients with acute embolic anterior circulation large-vessel occlusion treated with thrombectomy, we analyzed 108 patients admitted from January 2015 to December 2019 who underwent evaluation of leptomeningeal collateral status on pretreatment CTA. Clinical characteristics, extent of leukoaraiosis on MR imaging, embolic stroke subtype, time of imaging, occlusive thrombus characteristics, presenting stroke severity, and clinical outcome were collected. The clinical indicators of good collateral status (>50% collateral filling of the occluded territory) were analyzed using multivariate logistic regression analysis.

RESULTS

Good collateral status was present in 67 patients (62%) and associated with independent functional outcomes at 3 months. Reduced leukoaraiosis (total Fazekas score, 0-2) was positively related to good collateral status (OR, 9.57; 95% CI, 2.49-47.75), while the cardioembolic stroke mechanism was inversely related to good collateral status (OR, 0.17; 95% CI, 0.02-0.87). In 82 patients with cardioembolic stroke, shorter thrombus length (OR, 0.91 per millimeter increase; 95% CI, 0.82-0.99) and reduced leukoaraiosis (OR, 5.79; 95% CI, 1.40-29.61) were independently related to good collateral status.

CONCLUSIONS

Among patients with embolic large-vessel occlusion, reduced leukoaraiosis, noncardiac embolism mechanisms including embolisms of arterial or undetermined origin, and shorter thrombus length in cardioembolism are indicators of good collateral flow.

Predictive Value of CT Perfusion Imaging on the Basis of Automatic Segmentation Algorithm to Evaluate the Collateral Blood Flow Status on the Outcome of Reperfusion Therapy for Ischemic Stroke

Our objective was to study the predictive value of CT perfusion imaging based on automatic segmentation algorithm for evaluating collateral blood flow status in the outcome of reperfusion therapy for ischemic stroke. All data of 30 patients with ischemic stroke reperfusion in our hospital were collected and examined by CT perfusion imaging. Convolutional neural network (CNN) algorithm was used to segment perfusion imaging map and evaluate the results. The patients were grouped by regional leptomeningeal collateral score (rLMCs). Binary logistic regression was used to analyze the independent influencing factors of collateral blood flow on brain CT perfusion. The modified Scandinavian Stroke Scale was used to evaluate the prognosis of patients, and the effects of different collateral flow conditions on prognosis were obtained. The accuracy of CNN segmentation image is 62.61%, the sensitivity is 87.42%, the similarity coefficient is 93.76%, and the segmentation result quality is higher. Blood glucose (95% CI = 0.943, P=0.028) and ischemic stroke history (95% CI = 0.855, P=0.003) were independent factors affecting the collateral blood flow status of stroke patients. CBF (95% CI = 0.818, P=0.008) and CBV (95% CI = 0.796, P=0.016) were independent influencing factors of CT perfusion parameters. After 3 weeks of onset, the prognostic function defect score of the good collateral flow group (11.11%) was lower than that of the poor group (41.67%) (P < 0.05). The automatic segmentation algorithm has more accurate segmentation ability for stroke CT perfusion imaging and plays a good auxiliary role in the diagnosis of clinical stroke reperfusion therapy. The collateral blood flow state based on CT perfusion imaging is helpful to predict the treatment outcome of patients with ischemic stroke and further predict the prognosis of patients.

Corneal nerve loss as a surrogate marker for poor pial collaterals in patients with acute ischemic stroke

In patients with acute ischemic stroke, pial collaterals play a key role in limiting neurological disability by maintaining blood flow to ischemic penumbra. We hypothesized that patient with poor pial collaterals will have greater corneal nerve and endothelial cell abnormalities. In a cross-sectional study, 35 patients with acute ischemic stroke secondary to middle cerebral artery (MCA) occlusion with poor (n = 12) and moderate-good (n = 23) pial collaterals and 35 healthy controls underwent corneal confocal microscopy and quantification of corneal nerve and endothelial cell morphology. In patients with MCA stroke, corneal nerve fibre length (CNFL) (P < 0.001), corneal nerve fibre density (CNFD) (P = 0.025) and corneal nerve branch density (CNBD) (P = 0.002) were lower compared to controls. Age, BMI, cholesterol, triglycerides, HDL, LDL, systolic blood pressure, NIHSS and endothelial cell parameters did not differ but mRS was higher (p = 0.023) and CNFL (p = 0.026) and CNBD (p = 0.044) were lower in patients with poor compared to moderate-good collaterals. CNFL and CNBD distinguished subjects with poor from moderate-good pial collaterals with an AUC of 72% (95% CI 53–92%) and 71% (95% CI 53–90%), respectively. Corneal nerve loss is greater in patients with poor compared to moderate-good pial collaterals and may act as a surrogate marker for pial collateral status in patients with ischemic stroke.

Influence of white matter lesions on the prognosis of acute cardioembolic stroke without reperfusion therapy

Background

Few studies have investigated the influence of white matter lesions (WMLs) on the prognosis of acute cardioembolic stroke (CES). We aimed to explore the role of WMLs in predicting 3-month prognosis of CES without reperfusion therapy.

Methods

A number of 251 acute CES patients without reperfusion therapy at a single center were retrospectively recruited. The severity of WMLs was evaluated by Fazekas scale and patients were divided into mild WMLs group (188 cases, Fazekas ≤ 2 points) and moderate to severe WMLs group (63 cases, Fazekas ≥ 3 points) accordingly. General data and clinical features of the two groups were compared. Functional outcomes of patients were followed up for 3 months using the modified Rankin scale (mRS) and patients were divided into poor outcome group (mRS ≥ 3) and favorable outcome group (mRS ≤ 2). The effect of WMLs on the prognosis was identified by binary logistic regression.

Results

Patients in moderate to severe WMLs group were older (P < 0.001). Also, they had higher baseline National Institutes of Health Stroke Scale (NIHSS) score (P < 0.001) and elevated incidence of asymptomatic cerebral hemorrhage (P = 0.040) and stroke associated pneumonia (P = 0.001) than those in mild WMLs group. At 3 months, there were 100 cases in the poor outcome group. Patients in poor outcome group had higher baseline NIHSS score, increased proportion of moderate to severe WMLs, and elevated incidence of stroke associated pneumonia than those in favorable outcome group (P < 0.001). Binary logistic regression analysis showed that moderate to severe WMLs (odds ratio [OR] = 4.105, 95 % confidence interval [CI] = 1.447–11.646), baseline NIHSS score (OR = 1.368, 95 % CI = 1.240–1.511), and stroke-associated pneumonia (OR = 4.840, 95 %CI = 1.889–12.400) were independent risk factors for poor outcome.

Conclusions

Moderate to severe WMLs is an independent risk factor for prognosis of CES patients without reperfusion therapy.

White Matter Lesions and Outcomes After Endovascular Treatment for Acute Ischemic Stroke: MR CLEAN Registry Results

Supplemental Digital Content is available in the text.

Background:

Cerebral white matter lesions (WMLs) have been associated with a greater risk of poor functional outcome after ischemic stroke. We assessed the relations between WML burden and radiological and clinical outcomes in patients treated with endovascular treatment in routine practice.

Methods:

We analyzed data from the MR CLEAN Registry (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischaemic Stroke in the Netherlands)—a prospective, multicenter, observational cohort study of patients treated with endovascular treatment in the Netherlands. WMLs were graded on baseline noncontrast computed tomography using a visual grading scale. The primary outcome was the score on the modified Rankin Scale at 90 days. Secondary outcomes included early neurological recovery, successful reperfusion (extended Thrombolysis in Cerebral Infarction ≥2b), futile recanalization (modified Rankin Scale score ≥3 despite successful reperfusion), and occurrence of symptomatic intracranial hemorrhage. We used multivariable logistic regression models to assess associations between WML severity and outcomes, taking the absence of WML on noncontrast computed tomography as the reference category.

Results:

Of 3180 patients included in the MR CLEAN Registry between March 2014 and November 2017, WMLs were graded for 3046 patients and categorized as none (n=1855; 61%), mild (n=608; 20%), or moderate to severe (n=588; 19%). Favorable outcome (modified Rankin Scale score, 0–2) was achieved in 838 patients (49%) without WML, 192 patients (34%) with mild WML, and 130 patients (24%) with moderate-to-severe WML. Increasing WML grades were associated with a shift toward poorer functional outcome in a dose-dependent manner (adjusted common odds ratio, 1.34 [95% CI, 1.13–1.60] for mild WML and 1.67 [95% CI, 1.39–2.01] for moderate-to-severe WML; P_trend, <0.001). Increasing WML grades were associated with futile recanalization (P_trend, <0.001) and were inversely associated with early neurological recovery (P_trend, 0.041) but not with the probability of successful reperfusion or symptomatic intracranial hemorrhage.

Conclusions:

An increasing burden of WML at baseline is associated with poorer clinical outcomes after endovascular treatment for acute ischemic stroke but not with the probability of successful reperfusion or symptomatic intracranial hemorrhage.

Associations Between White Matter Hyperintensity Burden, Cerebral Blood Flow and Transit Time in Small Vessel Disease: An Updated Meta-Analysis

Cerebral small vessel disease (SVD) is a major contributor to stroke and dementia, characterized by white matter hyperintensities (WMH) on neuroimaging. WMH are associated with reduced cerebral blood flow (CBF) cross-sectionally, though longitudinal associations remain unclear. We updated a 2016 systematic review, identifying 30 new studies, 27 cross-sectional (n = 2,956) and 3 longitudinal (n = 440). Cross-sectionally, 10/27 new studies (n = 1,019) included sufficient data for meta-analysis, which we meta-analyzed with 24 previously reported studies (n = 1,161), total 34 (n = 2,180). Our meta-analysis showed that patients with lower CBF had worse WMH burden (mean global CBF: standardized mean difference (SMD): −0.45, 95% confidence interval (CI): −0.64, −0.27). Longitudinally, associations between baseline CBF and WMH progression varied: the largest study (5 years, n = 252) found no associations, while another small study (4.5 years, n = 52) found that low CBF in the periventricular WMH penumbra predicted WMH progression. We could not meta-analyse longitudinal studies due to different statistical and methodological approaches. We found that CBF was lower in WMH than in normal-appearing white matter in an additional meta-analysis (5 cross-sectional studies; n = 295; SMD: −1.51, 95% CI: −1.94, −1.07). These findings highlight that relationships between resting CBF and WMH are complex. Further longitudinal studies analyzing regional CBF and subsequent WMH change are required to determine the role of CBF in SVD progression.

Hemodynamics in acute stroke: Cerebral and cardiac complications

Hemodynamics is the study of blood flow, where parameters have been defined to quantify blood flow and the relationship with systemic circulatory changes. Understanding these perfusion parameters, the relationship between different blood flow variables and the implications for ischemic injury are outlined in the ensuing discussion. This chapter focuses on the hemodynamic changes that occur in ischemic stroke, and their contribution to ischemic stroke pathophysiology. We discuss the interaction between cardiovascular response and hemodynamic changes in stroke. Studying hemodynamic changes has a key role in stroke prevention, therapeutic implications and prognostic importance in acute ischemic stroke: preexisting hemodynamic and autoregulatory impairments predict the occurrence of stroke. Hemodynamic failure predisposes to the formation of thromboemboli and accelerates infarction due to impairing compensatory mechanisms. In ischemic stroke involving occlusion of a large vessel, persistent collateral circulation leads to preservation of ischemic penumbra and therefore justifying endovascular thrombectomy. Following thrombectomy, impaired autoregulation may lead to reperfusion injury and hemorrhage.

Impact of leukoaraiosis severity on the association of outcomes of mechanical thrombectomy for acute ischemic stroke: a systematic review and a meta-analysis

Background

Leukoaraiosis (LA) severity is associated with poor outcome after mechanical thrombectomy (MT) for acute ischemic stroke (AIS) caused by large vessel occlusion. This meta-analysis aimed to assess the association of LA severity with AIS-related risk factors and outcomes of MT.

Methods

PubMed, Web of Science, EMBASE, and Cochrane Collaboration Database was searched for studies on MT for AIS with LA. We conducted a random-effects meta-analysis for the prevalence of stroke risk factors and the MT outcome in the absent to moderate LA and severe LA groups.

Results

We included seven cohort studies involving 1294 participants (1019 with absent to moderate LA and 275 with severe LA). The absent to moderate LA group had a significantly lower prevalence of coronary artery disease (odds ratio [OR] 0.43; 95% CI 0.29–0.66), atrial fibrillation (OR, 0.26; 95% CI 0.17–0.38), hypertension (OR, 0.39; 95% CI 0.24–0.61), and ischemic stroke (OR, 0.27; 95% CI 0.15–0.50) than the severe LA group. There were no significant between-group differences in symptom onset to recanalization time (364.4 versus 356.2 min, mean difference 19.4; 95% CI − 28.3 to 67.2), final recanalization rate (modified thrombolysis in cerebral infarction score of 2b/3; OR, 0.87; 95% CI 0.55–1.38), and symptomatic intracranial hemorrhage (OR, 0.62; 95% CI 0.34–1.11). The absent to moderate LA group had a higher good functional outcome (modified Rankin Scale score of 0–2 at 90 days; OR, 4.55; 95% CI 3.20–6.47) and a lower mortality rate (179/1019 vs 108/275; OR, 0.28; 95% CI 0.20–0.39).

Conclusion

There are unique differences in the characteristics of risk factors and clinical outcomes of ischemic stroke across patients with LA of different severity. Patients with severe LA are more likely to be associated with risk factors for cerebrovascular disease and have a poor post-MT outcome.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-10167-0) contains supplementary material, which is available to authorized users.