Does Small Vessel Disease Burden Impact Collateral Circulation in Ischemic Stroke Treated by Mechanical Thrombectomy?

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.

Total cerebral small vessel disease burden and stroke outcomes in large vessel occlusion stroke receiving endovascular treatment: A systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease (CSVD) is prevalent in the population, especially among the elderly. Various types of CSVD markers commonly coexist, and the neurological function outcome is affected by their combined effect. Studies investigating the association between total CSVD burden and stroke outcomes in large vessel occlusion (LVO) stroke receiving endovascular treatment (EVT) are expanding but have not been systematically assessed.

METHODS

We systematically searched the PubMed, Embase, and Cochrane databases for relevant clinical studies. The total CSVD burden score summarized the markers of CSVD, including lacunes, white matter hyperintensities (WMHs), cerebral microbleeds (CMBs), and enlarged perivascular spaces (EPVSs), which was a comprehensive index of overall CSVD burden. The pooled odds ratios (ORs) were used to calculate the association between high total CSVD burden score and outcomes of EVT in patients with LVO stroke. The primary outcome was poor functional outcome, which was defined as a modified Rankin Scale score (mRS) ≥ 3 at 90 days after EVT. The secondary outcomes were symptomatic intracranial hemorrhage (sICH) and poor collateral flow.

RESULTS

Overall, 6 eligible studies with 1,774 patients with LVO stroke undergoing EVT were pooled in meta-analysis. High overall CSVD burden score was significantly associated with increased risks of poor functional outcome at 90 days (pooled OR 2.86, 95 % CI 1.31-6.25, p = 0.008). Besides, high overall CSVD burden score was associated with sICH (pooled OR 2.07, 95 % CI 0.38-5.17; p = 0.118) and poor collateral flow (pooled OR 1.57, 95 % CI 0.75-3.27; p = 0.232), but were not statistically significant.

CONCLUSIONS

High overall CSVD burden was associated with increased risks of unfavorable outcomes in patients with LVO stroke undergoing EVT.

Overall cerebral small vessel disease burden is associated with outcome of acute ischemic stroke after mechanical thrombectomy

OBJECTIVES

To investigate the association between the overall cerebral small vessel disease (CSVD) burden and the therapeutic outcome of mechanical thrombectomy (MT) in patients with acute anterior circulation large-vessel occlusion stroke.

MATERIALS AND METHODS

Data of patients who achieved successful revascularization after MT for acute anterior circulation large-vessel occlusion stroke in the Ningbo Medical Center Lihuili Hospital between April 2017 and January 2022 were retrospectively analyzed. The overall CSVD burden was evaluated by total CSVD score based on MRI images. According to the 90-day modified Rankin Scale (mRS) score, the participants were divided into the Good outcome group (mRS score 0-2) and Poor outcome group (mRS score 3-6). Multivariate Logistic regression was applied to assess the relationship between the overal CSVD burdern and 90-day outcome.

RESULTS

In total, 145 eligible patients were included and classified into the Good outcome group (n = 77, 62.3% males, mean age: 64.92 ± 13.67 years) and Poor outcome group (n = 68, 50% males, mean age: 69.76 ± 10.88 years). Symptomatic intracranial hemorrhage (OR = 2.788, 95%CI: 1.143-8.745, P = 0.048), poor preoperative collateral status (OR = 3.619, 95%CI: 1.670-7.844, P = 0.001), and high total CSVD score (score 2: OR = 3.800, 95%CI: 1.173 = 12.311, P = 0.026; score 3: OR = 7.529, 95%CI: 1.555-36.460, P = 0.012) were independently prognostic for poor 90-day outcome in patients receiving MT.

CONCLUSION

This study identified that the overall CSVD burden was independently associated with the prognosis of patients receiving MT for acute anterior circulation large-vessel occlusion stroke.

White matter hyperintensity burden and collateral circulation in acute ischemic stroke with large artery occlusion

OBJECTIVE

This study aimed to investigate the association between white matter hyperintensity (WMH) burden and pial collaterals in acute strokes caused by intracranial large artery occlusion treated with mechanical thrombectomy in the anterior circulation, focusing on stroke subtypes.

METHODS

Consecutive patients undergoing mechanical thrombectomy between December 2019 and June 2022 were retrospectively screened. The Fazekas scale assessed WMH burden. Pial collaterals were categorized as either poor (0-2) or good (3-4) based on the Higashida score. A multivariable analysis was used to determine the relationship between WMH burden and pial collaterals. Subgroup analyses delved into associations stratified by stroke subtypes, namely cardioembolism (CE), tandem lesions (TLs), and intracranial atherosclerosis (ICAS).

RESULTS

Of the 573 patients included, 274 (47.8%) demonstrated poor pial collaterals. Multivariable regression indicated a strong association between extensive WMH burden (Fazekas score of 3-6) and poor collaterals [adjusted OR 3.04, 95% CI 1.70-5.46, P < 0.001]. Additional independent predictors of poor collaterals encompassed ICAS-related occlusion (aOR 0.26, 95% CI 0.09-0.76, P = 0.014), female sex (aOR 0.63, 95% CI 0.41-0.96, P = 0.031), and baseline Alberta Stroke Program Early Computed Tomography scores (aOR 0.80, 95% CI 0.74-0.88, P < 0.001). Notably, an interaction between extensive WMH burden and stroke subtypes was observed in predicting poor collaterals (P = 0.001), being pronounced for CE (adjusted OR 2.30, 95% CI 1.21-4.37) and TLs (adjusted OR 5.09, 95% CI 2.32-11.16), but was absent in ICAS (adjusted OR 1.24, 95% CI 0.65-2.36).

CONCLUSIONS

Among patients treated with mechanical thrombectomy for anterior circulation large artery occlusion, extensive WMH burden correlates with poor pial collaterals in embolic occlusion cases (CE and TLs), but not in ICAS-related occlusion.

Asymmetry of Lacunae between Brain Hemispheres Is Associated with Atherosclerotic Occlusions of Middle Cerebral Artery

Cerebral small vessel disease (CSVD) commonly coexists with intracranial atherosclerotic stenosis (ICAS). Previous studies have tried to evaluate the relationship between ICAS and CSVD; however, they have yielded varied conclusions. Furthermore, the methodology of these studies is not very rigorous, as they have evaluated the association between ICAS and CSVD of bilateral hemispheres rather than the affected hemisphere. Unilateral middle cerebral artery atherosclerotic occlusion (uni-MCAO) is a favorable model to solve this problem.

MATERIAL AND METHODS

Patients with uni-MCAO were retrospectively observed. Imaging characteristics, including lacunae, white matter hyperintensities (WMH), enlarged perivascular spaces (EPVS), and cerebral microbleeds (CMBs), were compared between the hemisphere ipsilateral to the MCAO and the contralateral hemisphere.

RESULTS

A total of 219 patients (median age 57 years; 156 males) were enrolled. Compared with the contralateral side, increased quality of lacunae (median, IQR, 0, 2 vs. 0, 1; p < 0.001) and elevated CSVD score (median, IQR, 0, 1 vs. 0, 1; p = 0.004) were found in the occluded hemisphere. No significant differences were shown for WMH, EPVS, and CMBs.

CONCLUSIONS

Uni-MCAO has a higher prevalence of lacunae in the ipsilateral hemisphere. However, no interhemispheric differences in WMH, EPVS, or CMBs were found.

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.

MRI for collateral assessment pre-thrombectomy and association with outcome: a systematic review and meta-analysis

PURPOSE

Various neuroimaging methods exist to assess the collateral circulation in stroke patients but much of the evidence is based on computed tomography. Our aim was to review the evidence for using magnetic resonance imaging for collateral status evaluation pre-thrombectomy and assess the impact of these methods on functional independence.

METHODS

We systematically reviewed EMBASE and MEDLINE for studies that evaluated baseline collaterals using MRI pre-thrombectomy and conducted a meta-analysis to express the relationship between good collaterals (defined variably as the presence [good] vs absence [poor] or quality [ordinal scores binarized as good-moderate vs poor] of collaterals) and functional independence (modified Rankin score mRS≤2) at 90 days. Outcome data were presented as relative risk (RR, 95% confidence interval, 95%CI). We assessed for study heterogeneity, publication bias, and conducted subgroup analyses of different MRI methods and affected arterial territories.

RESULTS

From 497 studies identified, we included 24 (1957 patients) for the qualitative synthesis, and 6 (479 patients) for the metanalysis. Good pre-thrombectomy collaterals were significantly associated with favorable outcome at 90 days (RR=1.91, 95%CI=1.36-2.68], p= 0.0002) with no difference between MRI methods and affected arterial territory subgroups. There was no evidence of statistical heterogeneity (I²=25%) among studies but there was evidence of publication bias.

CONCLUSION

In stroke patients treated with thrombectomy, good pre-treatment collaterals assessed using MRI are associated with double the rate of functional independence. However, we found evidence that relevant MR methods are heterogenous and under-reported. Greater standardization and clinical validation of MRI for collateral evaluation pre-thrombectomy are required.

Cerebral Small Vessel Disease Burden and Futile Reperfusion after Endovascular Treatment for Patients with Acute Ischemic Stroke

INTRODUCTION

Cerebral small vessel disease (SVD) burden includes increased risk of poor functional outcomes after acute ischemic stroke (AIS). We aimed to investigate the impact of cerebral SVD on 3-month functional outcomes in patients with AIS who received endovascular treatment (EVT) and to determine whether SVD is associated with futile reperfusion (FR).

METHODS

Using a multicenter stroke registry, we analyzed consecutive patients with AIS with either intracranial and/or extracranial anterior circulation large artery occlusion, who were treated with EVT and achieved successful reperfusion (thrombolysis in cerebral infarction grade 2b-3). The cerebral SVD burden was evaluated using baseline brain magnetic resonance imaging using a modified Fazekas score (mFS). The main outcome variable was FR, defined as poor functional outcomes (modified Rankin scale 3-6) at 3 months after stroke, despite successful recanalization. Secondary outcomes included stroke progression/recurrence and any hemorrhagic transformation.

RESULTS

Among 10,890 patients with AIS, 577 (5.3%) received EVT within 12  h of onset, including 354 who met study eligibility criteria. FR was observed in 191 patients (53.5%) and was positively associated with SVD burden. After adjustment for covariates including age, sex, stroke etiology, initial stroke severity, collateral status, Alberta stroke program early CT score, initial serum glucose, systemic blood pressure, and vascular risk factors, mFS grade 3 was significantly associated with FR (odds ratio: 3.93, 95% confidence interval: 1.602-9.619; p = 0.003).

CONCLUSIONS

We demonstrated that cerebral SVD assessed with baseline brain MRI is associated with the futility of successful recanalization after EVT and any hemorrhagic transformation but not with early stroke progression or recurrence. Nevertheless, our findings do not justify withholding EVT in otherwise eligible patients with AIS based on the presence of severe SVD.

A Review of Traditional Chinese Medicine, Buyang Huanwu Decoction for the Treatment of Cerebral Small Vessel Disease

Cerebral small vessel disease (CSVD) is often referred to as “collaterals disease” in traditional Chinese medicine (TCM), and commonly includes ischemic and hemorrhagic CSVD. TCM has a long history of treating CSVD and has demonstrated unique efficacy. Buyang Huanwu Decoction (BHD) is a classical TCM formula that has been used for the prevention and treatment of stroke for hundreds of years. BHD exerts its therapeutic effects on CSVD through a variety of mechanisms. In this review, the clinical and animal studies on BHD and CSVD were systematically introduced. In addition, the pharmacological mechanisms, active components, and clinical applications of BHD in the treatment of CSVD were reviewed. We believe that an in-depth understanding of BHD, its pharmacological mechanism, disease-drug interaction, and other aspects will help in laying the foundation for its development as a new therapeutic strategy for the treatment of CSVD.

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.

White Matter Hyperintensity Burden and Collateral Circulation in Large Vessel Occlusion Stroke

BACKGROUND AND PURPOSE

White matter hyperintensity (WMH), a marker of chronic cerebral small vessel disease, might impact the recruitment of leptomeningeal collaterals. We aimed to assess whether the WMH burden is associated with collateral circulation in patients treated by endovascular thrombectomy for anterior circulation acute ischemic stroke.

METHODS

Consecutive acute ischemic stroke due to anterior circulation large vessel occlusion and treated with endovascular thrombectomy from January 2015 to December 2017 were included. WMH volumes (periventricular, deep, and total) were assessed by a semiautomated volumetric analysis on fluid-attenuated inversion recovery-magnetic resonance imaging. Collateral status was graded on baseline catheter angiography using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology grading system (good when ≥3). We investigated associations of WMH burden with collateral status.

RESULTS

A total of 302 patients were included (mean age, 69.1±19.4 years; women, 55.6%). Poor collaterals were observed in 49.3% of patients. Median total WMH volume was 3.76 cm³ (interquartile range, 1.09-11.81 cm³). The regression analyses showed no apparent relationship between WMH burden and the collateral status measured at baseline angiography (adjusted odds ratio, 0.987 [95% CI, 0.971-1.003]; P=0.12).

CONCLUSIONS

WMH burden exhibits no overt association with collaterals in large vessel occlusive stroke.

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.

Effects of White Matter Hyperintensities on 90-Day Functional Outcome after Large Vessel and Non-Large Vessel Stroke

INTRODUCTION

White matter hyperintensity (WMH) burden is a critically important cerebrovascular phenotype related to the diagnosis and prognosis of acute ischemic stroke. The effect of WMH burden on functional outcome in large vessel occlusion (LVO) stroke has only been sparsely assessed, and direct LVO and non-LVO comparisons are currently lacking.

MATERIAL AND METHODS

We reviewed acute ischemic stroke patients admitted between 2009 and 2017 at a large healthcare system in the USA. Patients with LVO were identified and clinical characteristics, including 90-day functional outcomes, were assessed. Clinical brain MRIs obtained at the time of the stroke underwent quantification of WMH using a fully automated algorithm. The pipeline incorporated automated brain extraction, intensity normalization, and WMH segmentation.

RESULTS

A total of 1,601 acute ischemic strokes with documented 90-day mRS were identified, including 353 (22%) with LVO. Among those strokes, WMH volume was available in 1,285 (80.3%) who had a brain MRI suitable for WMH quantification. Increasing WMH volume from 0 to 4 mL, age, female gender, a number of stroke risk factors, presence of LVO, and higher NIHSS at presentation all decreased the odds for a favorable outcome. Increasing WMH above 4 mL, however, was not associated with decreasing odds of favorable outcome. While WMH volume was associated with functional outcome in non-LVO stroke (p = 0.0009), this association between WMH and functional status was not statistically significant in the complete case multivariable model of LVO stroke (p = 0.0637).

CONCLUSION

The burden of WMH has effects on 90-day functional outcome after LVO and non-LVO strokes. Particularly, increases from no measurable WMH to 4 mL of WMH correlate strongly with the outcome. Whether this relationship of increasing WMH to worse outcome is more pronounced in non-LVO than LVO strokes deserves additional investigation.

Collateral Recruitment Is Impaired by Cerebral Small Vessel Disease

Background and Purpose- Cerebral small vessel disease (SVD) is associated with increased stroke risk and poor stroke outcomes. We aimed to evaluate whether chronic SVD burden is associated with poor recruitment of collaterals in large-vessel occlusive stroke. Methods- Consecutive patients with middle cerebral artery or internal carotid artery occlusion presenting within 6 hours after stroke symptom onset who underwent thrombectomy from 2012 to 2017 were included. The prespecified primary outcome was poor collateral flow, which was assessed on baseline computed tomographic angiography (poor, ≤50% filling; good, >50% filling). Markers of chronic SVD on brain magnetic resonance imaging were rated for the extent of white matter hyperintensities, enlarged perivascular spaces, chronic lacunar infarctions and cerebral microbleeds using the Standards for Reporting Vascular Changes on Neuroimaging criteria. Severity of SVD was quantified by adding the presence of each SVD feature, with a total possible score of 0 to 4; each SVD type was also evaluated separately. Multivariable logistic regression analyses were performed to evaluate the relationships between SVD and poor collaterals, with adjustment for potential confounders. Results- Of the 100 eligible patients, the mean age was 65±16 years, median National Institutes of Health Stroke Scale score was 15, and 68% had any SVD. Poor collaterals were observed in 46%, and those with SVD were more likely to have poor collaterals than patients without SVD (aOR, 1.9 [95% CI, 1.1-3.2]). Of the SVD types, poor collaterals were significantly associated with white matter hyperintensities (aOR, 2.9 per Fazekas increment [95% CI, 1.6-5.3]) but not with enlarged perivascular spaces (adjusted odds ratio [aOR], 1.3 [95% CI, 0.4-4.0]), lacunae (aOR, 2.1 [95% CI, 0.6-7.1]), or cerebral microbleeds (aOR, 2.1 [95% CI, 0.6-7.8]). Having a greater number of different SVD markers was associated with a higher odds of poor collaterals (crude trend P<0.001; adjusted P=0.056). There was a dose-dependent relationship between white matter hyperintensity burden and poor collaterals: adjusted odds of poor collaterals were 1.5, 3.0, and 9.7 across Fazekas scores of 1 to 3 (Ptrend=0.015). No patient with an SVD score of 4 had good collaterals. Conclusions- Chronic cerebral SVD is associated with poor recruitment of collaterals in large vessel occlusive stroke. A prospective study to elucidate the potential mechanism of how SVD may impair the recruitment of collaterals is ongoing.

Association of atherosclerotic plaque features with collateral circulation status in elderly patients with chronic carotid stenosis

OBJECTIVE

To determine the association of carotid plaque features with collateral circulation status in elderly patients with moderate to severe carotid stenosis.

METHODS

Elderly patients (> 60 years) with moderate to severe carotid stenosis were recruited and categorized into good and poor collateral circulation groups, and underwent magnetic resonance imaging and computed tomography imaging. The carotid plaque features including lipid-rich necrotic core, intraplaque hemorrhage, calcification, and fibrous cap rupture (FCR) were evaluated, and maximum wall thickness, normalized wall index (NWI), and luminal stenosis were measured. The association between these variables and collateral circulation status was analyzed.

RESULTS

Of the 97 patients (78 males, mean age: 69.0 ± 6.1 years), 19 (19.6%) had poor collaterals. The poor collateral group had a significantly higher NWI (93.7% ± 5.0% vs. 89.0% ± 7.9%, P = 0.011), a greater extent of stenosis (80.0% ± 11.4% vs. 75.3% ± 9.4%, P = 0.036) and FCR (84.2% vs. 55.1%, P = 0.020) compared with good collateral group. Carotid NWI (OR = 3.83, 95% CI: 1.36-10.82, P = 0.011) and more FCR (OR = 6.77, 95% CI: 1.35-33.85, P = 0.020) were associated with poor collateral circulation after adjustment for the confounding factors. The combination of NWI, FCR, systolic blood pressure, and triglycerides had the highest area-under-the-curve (AUC = 0.85) for detection of poor collaterals.

CONCLUSIONS

Carotid plaque features, specifically NWI and FCR, are independently associated with poor collateral circulation, and the combination of carotid plaque features and traditional risk factors has a stronger predictive value for poor collateral circulation than plaque features alone.