Influence of preoperative embolisation on resection of brain arteriovenous malformations: cohort study.

PURPOSE: Preoperative endovascular embolisation is a widely used adjunct for the surgical treatment of brain arteriovenous malformations (AVMs). However, whether this improves completeness of AVM resection is unknown, as previous analyses have not adjusted for potential confounding factors. We aimed to determine if preoperative endovascular embolisation was associated with increased rate of complete AVM resection at first surgery, following adjustment for Spetzler-Martin grade items. METHODS: We identified a cohort of all patients undergoing first ever AVM resection in a specialist neurosciences unit in the NHS Lothian Health Board region of Scotland between June 2004 and June 2022. Data was prospectively extracted from medical records. Our primary outcome was completeness of AVM resection. We determined the odds of complete AVM resection using binomial logistic regression with adjustment for Spetzler-Martin grading system items: maximum nidus diameter, eloquence of adjacent brain and the presence of deep venous drainage. RESULTS: 88 patients (median age 40y [IQR 19-53], 55% male) underwent AVM resection. 34/88 (39%) patients underwent preoperative embolisation and complete resection was achieved at first surgery in 74/88 (84%). Preoperative embolisation was associated with increased adjusted odds of complete AVM resection (adjusted odds ratio [aOR] 8.6 [95% confidence interval (95% CI) 1.7-67.7]; p = 0.017). The presence of deep venous drainage was associated with reduced chance of complete AVM resection (aOR 0.18 [95% CI 0.04-0.63]; p = 0.009). CONCLUSIONS: Preoperative embolisation is associated with improved chances of complete AVM resection following adjustment for Spetzler-Martin grade, and should therefore be considered when planning surgical resection of AVMs.

Surgical management outcomes of intracranial arteriovenous malformations after preoperative embolization: a systematic review and meta-analysis.

OBJECTIVE: Preoperative embolization for brain arteriovenous malformations (AVMs) has been shown to mitigate morbidity for high-risk AVMs, chiefly by reducing lesional blood flow before resection. However, associated risks include postembolization AVM rupture, and the effect of preoperative embolization on outcome remains uncertain. We performed a meta-analysis of the literature on preoperative embolization for microsurgically treated AVMs. METHODS: A systematic review and meta-analysis were conducted of all English-language publications reporting clinical outcomes after combined embolization and surgical resection for AVMs. Single- and 2-arm analyses were performed using random-effects modeling. RESULTS: Thirty-six studies with 2108 patients were included in this analysis. Most patients (90.6%) who underwent embolization had at least a 50% obliteration of AVMs on posttreatment preoperative angiography, with a mean rate of obliteration of approximately 80% (range 28.8-100%). Among patients who had combined treatment, 3.4% (95% confidence interval [CI] 2.1-4.6%) experienced embolization-related hemorrhagic complications before surgery. Both treatment groups achieved excellent postsurgical complete resection rates (odds ratio [OR] 1.05; 95% CI 0.60-1.85). Neither the clinical outcome (OR 1.42; 95% CI 0.84-2.40) nor the total number of hemorrhagic complications (OR 1.84; 95% CI 0.88-3.85) was significantly different between the treatment groups. CONCLUSIONS: In this meta-analysis, preoperative embolization appears to have substantially reduced the lesional volume with active AV shunting before AVM resection. Anecdotally, preoperative embolization facilitates safe and efficient resection; however, differences in outcomes were not significant. The decision to pursue preoperative embolization remains a nuanced decision based on individual lesion anatomy and treatment team experience.

Predictors of first-pass reperfusion for mechanical thrombectomy in acute ischemic stroke.

BACKGROUND AND OBJECTIVE: Rapid reperfusion of ischemic penumbra in patients with acute stroke is critical to neurological recovery. Achieving reperfusion after first-pass mechanical thrombectomy has been associated with improved patient outcomes. However, the predictors for obtaining first-pass reperfusion are not well known. METHODS: A single-institution retrospective study of all patients who underwent mechanical thrombectomy at a tertiary care center from January 2010 until March 2019 was conducted to assess for predictors of first-pass reperfusion. RESULTS: A total of 257 patients were reviewed. Successful reperfusion was obtained in 63.4% of patients, and in 38% of patients on the first pass. On multivariate analysis, increasing door-to-puncture time was a negative predictor of FPR (OR 0.989, 95% CI = 0.980-0.997) and use of combined thrombectomy technique with stent-retriever and aspiration was a positive predictor of FPR compared to aspiration or stent-retriever alone (OR 4.441, 95% CI = 1.001-19.699). CONCLUSIONS: Combination therapy using stent-retriever and aspiration may increase the chance of obtaining FPR, whereas delays in starting the procedure after patient arrival may decrease the odds of FPR. Rapid thrombectomy initiation and procedural technique may play in optimizing rates of FPR and ultimately patient outcomes, however, randomized controlled trials assessing these variables are necessary to determine optimal treatment strategies.

Middle Meningeal Artery Embolization Versus Conventional Treatment of Chronic Subdural Hematomas.

BACKGROUND: Middle meningeal artery (MMA) embolization is an emerging minimally invasive endovascular technique for chronic subdural hematoma (cSDH). Currently, limited literature exists on its safety and efficacy compared with conventional treatment (open-surgical-evacuation-only). OBJECTIVE: To compare MMA embolization to conventional treatment. METHODS: Retrospective analysis of patients with cSDHs treated with MMA embolization in a single center from 2018 to 2019 was performed. Comparisons were made with a historical conventional treatment cohort from 2006 to 2016. Propensity score matching analysis was used to assemble a balanced group of subjects. RESULTS: A total of 357 conventionally treated cSDH and 45 with MMA embolization were included. After balancing with propensity score matching, a total of 25 pairs of cSDH were analyzed. Comparing the embolization with the conventional treatment group yielded no significant differences in complications (4% vs 4%; P > .99), clinical improvement (82.6% vs 83.3%; P = .95), cSDH recurrence (4.3% vs 21.7%; P = .08), overall re-intervention rates (12% vs 24%; P = .26), modified Rankin scale >2 on last follow-up (17.4% vs 32%; P = .24), as well as mortality (0% vs 12%; P = .09). Radiographic improvement at last follow-up was significantly higher in the open surgery cohort (73.9% vs 95.6%; P = .04). However, there was a trend for lengthier last follow-up for the historical cohort (72 vs 104 d; P = .07). CONCLUSION: There was a trend for lower recurrence and mortality rates in the embolization era cohort. There were significantly higher radiological improvement rates on last follow-up in the surgical only cohort era. There were no significant differences in complications and clinical improvement.

The Role of Anesthesia during Intra-Arterial Mechanical Thrombectomy for theTreatment of Acute Ischemic Stroke.

Background Type of sedation (conscious sedation (CS) or general anesthesia (GA)) during Intra-arterial mechanical thrombectomy (IAMT) for treatment of acute ischemic stroke may affect patient outcomes. Previous studies suggested that CS cohorts have a higher probability of good outcome than GA cohorts. However, CS cohorts had lower initial NIH stroke scores (NIHSS). This study offers an investigation into outcomes after IAMT based on sedation type. Methods Patients at our institution who underwent IAMT for treatment of acute ischemic stroke caused by anterior circulation occlusion between 2013-2015 were included in the study. Primary endpoint was functional outcome on the modified Rankin Scale (mRS) at 90 days post-IAMT. Secondary endpoints included NIHSS at 48 hours post-IAMT, time from CT scan to puncture and from puncture to initial recanalization, recanalization as defined by the Thrombolysis in Cerebral Ischemia (TICI) score, intensive care and hospital length of stay, and all-cause in-hospital mortality. Results Thirty nine patients were included in analysis; 17 received GA and 22 received CS. Cohorts were similar in baseline characteristics, including NIHSS. The 90-day mRS was not significantly different between cohorts, as was the case for most secondary endpoints. Successful recanalization was higher in both groups than previously reported and a significantly higher TICI 3 recanalization rate was achieved in the GA cohort. Conclusions We show that equal outcomes are possible with either CS or GA if initial NIHSS is comparable. It seems reasonable for neuro-interventionalists to continue practicing using their personal preference for sedation. However, prospective randomized trials are still needed.

Bradycardia and Asystole in Patients Undergoing Symptomatic Chronically Occluded Internal Carotid Artery Recanalization.

BACKGROUND: Reports have emerged describing the successful endovascular recanalization of the chronically occluded internal carotid artery (COICA). The impact this restoration of flow has on the sensitive carotid sinus baroreceptors has not been previously described. In this manuscript, we present the largest COICA surgical series to date, with a specific focus on perioperative heart rate abnormalities. METHODS: Patient demographics were obtained, and the COICAs were radiographically classified based on the anatomic distribution of the stenosis and collateral flow. Thirty-six patients had a total of 37 COICA revascularization procedures. RESULTS: A total of 23 patients had intraprocedural bradycardia during balloon angioplasty. Three patients went into transient asystole during the procedure, and 2 of these patients had symptomatic bradycardia with ischemic cerebral changes, 1 of which required permanent pacemaking. All other patients had immediate resolution of their bradycardia, asystole, and neurologic symptoms immediately following balloon deflation and pharmaceutical management. There was a statistically significant difference in the observed proportion of bradycardic patients among COICA classifications (P = 0.014). There was no statistically significant difference in mean age between patients with bradycardia and those without (aged 63.36 vs. 67.71 years, P = 0.2265). CONCLUSIONS: Bradycardia associated with angioplasty of the carotid bulb was observed in the majority of patients receiving COICA revascularization. A small percentage of these patients were symptomatic. Our results suggest that carotid sinus baroreceptors remain active while residing in a complete arterial occlusion, and close monitoring is necessary during balloon angioplasty of the proximal COICA.

The effect of preoperative embolization and flow dynamics on resection of brain arteriovenous malformations.

OBJECTIVE: Preoperative embolization of brain arteriovenous malformations (AVMs) is performed to facilitate resection, although its impact on surgical performance has not been clearly defined. The authors tested for associations between embolization and surgical performance metrics. METHODS: The authors analyzed AVM cases resected by one neurosurgeon from 2006 to 2017. They tested whether cases with and without embolization differed from one another with respect to patient and AVM characteristics using t-tests for continuous variables and Fisher's exact tests for categorical variables. They used simple and multivariable regression models to test whether surgical outcomes (blood loss, resection time, surgical clip usage, and modified Rankin Scale [mRS] score) were associated with embolization. Additional regression analyses integrated the peak arterial afferent contrast normalized for the size of the region of interest (Cmax/ROI) into models as an additional predictor. RESULTS: The authors included 319 patients, of whom 151 (47%) had preoperative embolization. Embolized AVMs tended to be larger (38% with diameter > 3 cm vs 19%, p = 0.001), less likely to have hemorrhaged (48% vs 63%, p = 0.013), or be diffuse (19% vs 29%, p = 0.045). Embolized AVMs were more likely to have both superficial and deep venous drainage and less likely to have exclusively deep drainage (32% vs 17% and 12% vs 23%, respectively; p = 0.002). In multivariable analysis, embolization was not a significant predictor of blood loss or mRS score changes, but did predict longer operating times (+29 minutes, 95% CI 2-56 minutes; p = 0.034) and increased clip usage (OR 2.61, 95% CI 1.45-4.71; p = 0.001). Cmax/ROI was not a significant predictor, although cases with large Cmax/ROI tended to have longer procedure times (+25 minutes per doubling of Cmax/ROI, 95% CI 0-50 minutes; p = 0.051). CONCLUSIONS: In this series, preoperative embolization was associated with longer median resection times and had no association with intraoperative blood loss or mRS score changes.

Endovascular Therapy and Ethnic Disparities in Stroke Outcomes.

BACKGROUND AND PURPOSE: Ethnic disparities in stroke are well described, with a higher incidence of disability and increased mortality in Blacks versus Whites. We sought to compare the clinical outcomes between those ethnic groups after stroke endovascular therapy (ET). METHODS: We performed a retrospective review of the prospectively acquired Grady Endovascular Stroke Outcomes Registry between September 1, 2010 and September 30, 2015. Patients were dichotomized into two groups - Caucasians and African-Americans - and matched for age, pretreatment glucose level, and baseline National Institutes of Health Stroke Scale (NIHSS) score. Baseline characteristics as well as procedural and outcome parameters were compared. RESULTS: Out of the 830 patients treated with ET, 308 pairs of patients (n = 616) underwent primary analysis. African-Americans were younger (p < 0.01), had a higher prevalence of hypertension (p < 0.01) and diabetes (p = 0.04), and had higher Alberta Stroke Program Early CT Score values (p = 0.03) and shorter times to treatment (p = 0.01). Blacks more frequently had Medicaid coverage and less private insurance (29.6 vs. 11.4% and 41.5 vs. 60.3%, respectively, p < 0.01). The remaining baseline characteristics, including baseline NIHSS score and CT perfusion-derived ischemic core volumes, were well balanced. There were no differences in the overall distribution of 90-day modified Rankin scale scores (p = 0.28), rates of successful reperfusion (84.7 vs. 85.7%, p = 0.91), good outcomes (49.1 vs. 44%, p = 0.24), or parenchymal hematomas (6.5 vs. 6.8%, p = 1.00). Blacks had lower 90-day mortality rates (18 vs. 24.6%, p = 0.04) in univariate analysis, which persisted as a nonsignificant trend after adjustment for potential confounders (OR 0.52, 95% CI 0.26-1.03, p = 0.06). CONCLUSIONS: Despite unique baseline characteristics, African-Americans treated with ET for large vessel occlusion strokes have similar outcomes as Caucasians. Greater availability of ET may diminish the ethnic/racial disparities in stroke outcomes.

Risk of subsequent stroke, with or without extracranial-intracranial bypass surgery: a nationwide, retrospective, population-based study.

OBJECTIVEAlthough no benefits of extracranial-intracranial (EC-IC) bypass surgery in preventing secondary stroke have been identified previously, the outcomes of initial symptomatic ischemic stroke and stenosis and/or occlusion among the Asian population in patients with or without bypass intervention have yet to be discussed. The authors aimed to evaluate the subsequent risk of secondary vascular disease and cardiac events in patients with and without a history of this intervention.METHODSThis retrospective nationwide population-based Taiwanese registry study included 205,991 patients with initial symptomatic ischemic stroke and stenosis and/or occlusion, with imaging data obtained between 2001 and 2010. Patients who underwent EC-IC bypass (bypass group) were compared with those who had not undergone EC-IC bypass, carotid artery stenting, or carotid artery endarterectomy (nonbypass group). Patients with any previous diagnosis of ischemic or hemorrhagic stroke, moyamoya disease, cancer, or trauma were all excluded.RESULTSThe risk of subsequent ischemic stroke events decreased by 41% in the bypass group (adjusted hazard ratio [HR] 0.59, 95% CI 0.46-0.76, p < 0.001) compared with the nonbypass group. The risk of subsequent hemorrhagic stroke events increased in the bypass group (adjusted HR 2.47, 95% CI 1.67-3.64, p < 0.001) compared with the nonbypass group.CONCLUSIONSBypass surgery does play an important role in revascularization of the ischemic brain, while also increasing the risk of hemorrhage in the early postoperative period. This study highlights the fact that the high risk of bypass surgery obscures the true benefit of revascularization of the ischemic brain and also emphasizes the importance of developing improved surgical technique to treat these high-risk patients.

Low Morbidity after Extracranial-Intracranial Bypass Operation. The Danish Extracranial-Intracranial Bypass Study: A Nationwide Survey.

BACKGROUND: Patients with symptomatic atherosclerotic carotid artery occlusion (SACAO) have a high risk of a recurrent stroke. Extracranial-intracranial bypass (EC-IC bypass) has been shown not to improve outcome compared with medical treatment alone because long-term prevention of recurrent stroke in operated patients was offset by high perioperative stroke rates. We report our experience with EC-IC bypass operated at an experienced high-volume centre. METHODS: We conducted a nationwide observational study of EC-IC bypass patients operated in the years 2007-2016 due to SACAO with ongoing clinical symptoms or progression on MRI and severe haemodynamic failure (SHF). Perioperative stroke and death within 30 days after the operation, ipsilateral stroke, bypass patency, transient ischaemic attack, and all-stroke events and deaths during long-term follow-up were registered prospectively. RESULTS: EC-IC bypass was performed in 48 patients with SHF and SACAO. The mean age was 64 (45-83) years. The mean follow-up was 3.6 years. The stroke rate after 30 days was 4.2%. No further ipsilateral strokes occurred during follow-up. Clinical symptoms arrested in all patients. Bypass patency rate was 94%. CONCLUSIONS: The perioperative stroke rate in EC-IC bypass operation, performed at a highly experienced centre, was low. During long-term follow-up, no ipsilateral stroke occurred. Consequently, EC-IC-bypass should still be considered for selected patients with SACAO, if operation can be carried out in experienced centres with low perioperative morbidity.

Endovascular Biopsy: In Vivo Cerebral Aneurysm Endothelial Cell Sampling and Gene Expression Analysis.

There is limited data describing endothelial cell (EC) gene expression between aneurysms and arteries partly because of risks associated with surgical tissue collection. Endovascular biopsy (EB) is a lower risk alternative to conventional surgical methods, though no such efforts have been attempted for aneurysms. We sought (1) to establish the feasibility of EB to isolate viable ECs by fluorescence-activated cell sorting (FACS), (2) to characterize the differences in gene expression by anatomic location and rupture status using single-cell qPCR, and (3) to demonstrate the utility of unsupervised clustering algorithms to identify cell subpopulations. EB was performed in 10 patients (5 ruptured, 5 non-ruptured). FACS was used to isolate the ECs and single-cell qPCR was used to quantify the expression of 48 genes. Linear mixed models and exploratory multilevel component analysis (MCA) and self-organizing maps (SOMs) were performed to identify possible subpopulations of cells. ECs were collected from all aneurysms and there were no adverse events. A total of 437 ECs was collected, 94 (22%) of which were aneurysmal cells and 319 (73%) demonstrated EC-specific gene expression. Ruptured aneurysm cells, relative controls, yielded a median p value of 0.40 with five genes (10%) with p values < 0.05. The five genes (TIE1, ENG, VEGFA, MMP2, and VWF) demonstrated uniformly reduced expression relative the remaining ECs. MCA and SOM analyses identified a population of outlying cells characterized by cell marker gene expression profiles different from endothelial cells. After removal of these cells, no cell clustering based on genetic co-expressivity was found to differentiate aneurysm cells from control cells. Endovascular sampling is a reliable method for cell collection for brain aneurysm gene analysis and may serve as a technique to further vascular molecular research. There is utility in combining mixed and clustering methods, despite no specific subpopulation identified in this trial.

Mechanical Thrombectomy for Middle Cerebral Artery Division Occlusions: A Systematic Review and Meta-Analysis.

BACKGROUND: Middle cerebral artery division (M2) occlusion was significantly underrepresented in recent mechanical thrombectomy (MT) randomized controlled trials, and the approach to this disease remains heterogeneous. OBJECTIVE: To conduct a systematic review and meta-analysis of outcomes at 90 days among patients undergoing MT for M2 middle cerebral artery (MCA) occlusions. METHODS: Five clinical databases were searched from inception through September 2016. Observational studies reporting 90-day modified Rankin Scale scores for patients undergoing MT for M2 MCA occlusions with an M1 MCA control group were selected. The primary outcome of interest was good clinical outcome 90 days after MT of an M1 or M2 MCA occlusion. Secondary outcomes of interest included mortality and excellent clinical outcome, recanalization rates, significant intracerebral hemorrhage, and procedural complications. RESULTS: A total of 323 publications were identified, and 237 potentially relevant articles were screened. Six studies were included in the analysis (M1 = 1,203, M2 = 258; total n = 1,461). We found no significant differences in good clinical outcomes (1.10 [95% CI, 0.83-1.44]), excellent clinical outcomes (1.07 [0.65-1.79]), mortality at 3 months (0.85 [0.58-1.24]), recanalization rates (1.06 [0.32-3.48]), and significant intracranial hemorrhage (1.19 [0.61-2.30]). CONCLUSIONS: MT of M2 MCA occlusions is as safe as that of main trunk MCA occlusions, and comparable in terms of clinical outcomes and hemorrhagic complications. Randomized clinical trials are needed to assess the impact of MT in patients with M2 occlusions, given that M1 MCA occlusions have different natural histories than M2 occlusions.

Is Reperfusion Useful in Ischaemic Stroke Patients Presenting with a Low National Institutes of Health Stroke Scale and a Proximal Large Vessel Occlusion of the Anterior Circulation?

BACKGROUND: In population-based studies, patients presenting with minor or mild stroke symptoms represent about two-thirds of stroke patients, and almost one-third of these patients are unable to ambulate independently at the time of discharge. Although mechanical thrombectomy (MT) has become the standard of care for acute ischaemic stroke with proximal large vessel occlusion (LVO) in the anterior circulation, the management of patients harbouring proximal occlusion and minor-to-mild stroke symptoms has not yet been determined by recent trials. The purpose of this study was to evaluate the impact of reperfusion on clinical outcome in low National Institutes of Health Stroke Scale (NIHSS) patients treated with MT. METHODS: We analysed 138 consecutive patients with acute LVO of the anterior circulation (middle cerebral artery M1 or M2 segment, internal carotid artery or tandem occlusion) with NIHSS <8, having undergone MT in 3 different centres. Reperfusion was graded using the modified thrombolysis in cerebral infarction (TICI) score and 3 grades were defined, ranging from failed or poor reperfusion (TICI 0, 1, 2A) to complete reperfusion (TICI 3). The primary clinical endpoint was an excellent outcome defined as a modified Rankin score (mRs) 0-1 at 3-months. The impact of reperfusion grade was assessed in univariate and multivariate analyses. The secondary endpoints included favourable functional outcome (90-day mRS 0-2), death and safety concerns. RESULTS: Successful reperfusion was achieved in 81.2% of patients (TICI 2B, n = 47; TICI 3, n = 65). Excellent outcome (mRs 0-1) was achieved in 69 patients (65.0%) and favourable outcome (mRs ≤2) in 108 (78.3%). Death occurred in 7 (5.1%). Excellent outcome increased with reperfusion grades, with a rate of 34.6% in patients with failed/poor reperfusion, 61.7% in patients with TICI 2B reperfusion, and 78.5% in patients with TICI 3 reperfusion (p < 0.001). In multivariate analysis adjusted for patient characteristics associated with excellent outcome, the reperfusion grade remained significantly associated with an increase in excellent outcome; the OR (95% CI) was 3.09 (1.06-9.03) for TICI 2B and 6.66 (2.27-19.48) for TICI 3, using the failed/poor reperfusion grade as reference. Similar results were found regarding favourable outcome (90-day mRs 0-2) or overall mRS distribution (shift analysis). CONCLUSION: Successful reperfusion is strongly associated with better functional outcome among patients with proximal LVO in the anterior circulation and minor-to-mild stroke symptoms. Randomized controlled studies are mandatory to assess the benefit of MT compared with optimal medical management in this subset of patients.