Validation and Application for the Berlin Grading System of Moyamoya Disease in Adult Patients.

BACKGROUND: Traditional moyamoya disease (MMD) classification relies on morphological digital subtraction angiography (DSA) assessment, which do not reflect hemodynamic status, clinical symptoms, or surgical treatment outcome. OBJECTIVE: To (1) validate the new Berlin MMD preoperative symptomatology grading system and (2) determine the clinical application of the grading system in predicting radiological and clinical outcomes after surgical revascularization. METHODS: Ninety-six MMD patients (192 hemispheres) with all 3 investigations (DSA, magnetic resonance imaging [MRI], Xenon-CT) performed preoperatively at our institution (2007-2013) were included. Two clinicians independently graded the imaging findings according to the proposed criteria. Patients' modified Rankin Score (mRS) scores (preoperative, postoperative, last follow-up), postoperative infarct (radiological, clinical) were collected and statistical correlations performed. RESULTS: One hundred fifty-seven direct superficial temporal artery-middle cerebral artery bypasses were performed on 96 patients (66 female, mean age 41 yr, mean follow-up 4.3 yr). DSA, MRI, and cerebrovascular reserve capacity were independent factors associated hemispheric symptomatology (when analyzed individually or in the combined grading system). Mild (grade I), moderate (grade II), severe (grade III) were graded in 45, 71, and 76 hemispheres respectively; of which, clinical symptoms were found in 33% of grade I, 92% of grade II, 100% of grade III hemispheres (P < .0001). Two percent of grade I, 11% of grade II, 20% of grade III hemispheres showed postoperative radiological diffusion weighted image-positive ischemic changes or hemorrhage on MRI (P = .018). Clinical postoperative stroke was observed in 1.4% of grade II, 6.6% of grade III hemispheres (P = .077). The grading system also correlated well to dichotomized mRS postoperative outcome. CONCLUSION: The Berlin MMD grading system is able to stratify preoperative hemispheric symptomatology. Furthermore, it correlated with postoperative new ischemic changes on MRI, and showed a strong trend in predicting clinical postoperative stroke.

Redefining 'success': a systematic review and meta-analysis comparing outcomes between incomplete and complete revascularization.

BACKGROUND: Conventionally, 'successful' endovascular thrombectomy (EVT) had been defined as achieving revascularization of thrombolysis in cerebral infarction (TICI)-2B or greater, rather than as 'complete' (TICI-3) versus 'incomplete' (TICI-2B) revascularization. PURPOSE: We performed a systematic review and meta-analysis of studies comparing clinical outcomes between patients with TICI-2B and TICI-3 revascularization. METHODS: Multiple databases were searched for relevant publications between January 2003 and March 2018. Studies comparing outcomes between the TICI-2B and the TICI-3 group of acute ischemic stroke (AIS) patients treated with EVT were included. Random effects meta-analysis was performed to evaluate outcomes among TICI-2B and TICI-3 groups. The following outcomes were assessed: good neurologic outcome (modified Rankin Scale (mRS)≤2 at day 90), mortality, and intracerebral hemorrhage (ICH). RESULTS: Twenty-one studies comprising 2747 patients were identified. Patients with TICI-2B revascularization had mRS≤2 at day 90 rates of 46% (391/847) compared with 66% (522/791) for TICI-3 patients (OR 0.46, 95% CI 0.37 to 0.57). Mortality rates were significantly higher in the TICI-2B group (78/570, 14%) than in the TICI-3 group (55/709, 8%) (OR 2.00, 95% CI 1.38 to 2.91). The ICH rates were also significantly higher in the TICI-2B group as compared with the TICI-3 group (31% [134/439] vs. 22% [108/490]; OR 2.20, 95% CI 1.47 to 3.30). CONCLUSIONS: Differences in all major outcome measures were markedly better in patients with complete versus incomplete but still 'successful' revascularization using prior thresholds, with ORs in the order of those seen in recent definitive trials comparing EVT to an intravenous tissue plasminogen activator.

The Identification of Factors That Influence the Quality of Bypass Anastomosis and an Evaluation of the Usefulness of an Experimental Practical Scale in This Regard.

BACKGROUND: Several factors associated with interrupted and continuous suturing techniques affect the quality of bypass anastomosis. It is difficult to determine the impact of these factors during surgery. The primary objective of this study was to evaluate factors with the potential to influence the quality of bypass anastomosis using either interrupted or continuous suturing. A secondary objective was to evaluate the usefulness of a practical scale when comparing interrupted and continuous suturing techniques to improve bypass anastomosis. METHODS: Interrupted (n = 100) and continuous (n = 100) suturing techniques were used in 200 end-to-side bypasses to a depth of 3 cm and were assessed by 5 neurosurgeons. RESULTS: Vessel closing time (P < 0.001), stitch distribution (P < 0.001), intima-intima attachment (P < 0.001), and size of the orifice (P < 0.001) had a significant impact on the quality of the bypass regardless of the suturing technique used. The suturing technique used (interrupted or continuous) and positioning of the recipient vessel (vertical or horizontal) did not significantly influence the quality of anastomosis. Using multivariate analysis, the highest statistical significance with regard to bypass quality was attributed to the large size of the orifice and intimal attachment. CONCLUSIONS: There were advantages and disadvantages to both suturing techniques. The scale was a practical way to measure and improve performance.

Guidelines for evaluation and management of cerebral collateral circulation in ischaemic stroke 2017.

Collateral circulation plays a vital role in sustaining blood flow to the ischaemic areas in acute, subacute or chronic phases after an ischaemic stroke or transient ischaemic attack. Good collateral circulation has shown protective effects towards a favourable functional outcome and a lower risk of recurrence in stroke attributed to different aetiologies or undergoing medical or endovascular treatment. Over the past decade, the importance of collateral circulation has attracted more attention and is becoming a hot spot for research. However, the diversity in imaging methods and criteria to evaluate collateral circulation has hindered comparisons of findings from different cohorts and further studies in exploring the clinical relevance of collateral circulation and possible methods to enhance collateral flow. The statement is aimed to update currently available evidence and provide evidence-based recommendations regarding grading methods for collateral circulation, its significance in patients with stroke and methods under investigation to improve collateral flow.

Time to Reset the Definition of Successful Revascularization in Endovascular Treatment of Acute Ischemic Stroke.

BACKGROUND: A 2013 consensus statement recommended the use of the modified Treatment In Cerebral Ischemia (mTICI) scale to evaluate angiographic revascularization after endovascular treatment (EVT) of acute ischemic stroke due to its higher inter-rater agreement and capacity of clinical outcome prediction. The current definition of successful revascularization includes the achievement of grades mTICI 2b or 3. However, mTICI 2b grade encompasses a large heterogeneity of revascularization states, and prior studies suggested that the magnitude of benefit derived from mTICI 2b and mTICI 3 does not seem to be equivalent. In a way to restrain the referred heterogeneity, Goyal et al. [J Neurointerv Surg 2014; 6: 83-86] proposed a revised mTICI scale that includes a 2c grade (rTICI). METHODS: Retrospective analysis of prospectively collected data from consecutive cases of EVT for anterior circulation large-vessel occlusion, performed between January 2015 and July 2017. Patients with mTICI 2b or 3 grades were reclassified according to the rTICI scale, and the outcomes between the 3 revascularization grades (rTICI 2b, 2c, 3) compared. RESULTS: Our study population of 226 patients (64 rTICI 2b, 30 rTICI 2c, 132 rTICI 3) has a mean age of 71 years, 48.2% males, median baseline NIHSS of 16 (13-19) and ASPECTS of 8 (7-9). The 3 revascularization grades are represented by homogeneous populations. Logistic regression analysis showed statistically significant higher rates of functional independence at 3 months (65.9 vs. 50.0%; adjusted OR 0.39, 95% CI 0.18-0.86), with lower rates of mortality (8.3 vs. 15.6%; adjusted OR 3.54, 95% CI 1.14-10.97) and intracranial hemorrhage (ICH) in rTICI 3 than 2b groups. When comparing rTICI 3 with 2c groups, there were only statistically significant differences in the total ICH rate (8.3 vs. 26.7%; adjusted OR 7.08, 95% CI 1.80-27.82) but not in symptomatic ICH. CONCLUSIONS: These results corroborate the scarce prior findings suggesting that patients with rTICI 2c grade should be reported separately, since they have similar outcomes to rTICI 3, and better than rTICI 2b patients. Therefore, we suggest resetting the angiographic revascularization endpoint to perfect revascularization (rTICI 2c or 3 grades), a target that neurointerventionalists should strive to achieve.

Aneurysmal Subarachnoid Hemorrhage and Vasospasm.

Aneurysmal subarachnoid hemorrhage is potentially fatal and is associated with poor outcomes in many patients. Advances in neurosurgical and medical management of ruptured aneurysms have improved mortality rates in patients with aneurysmal subarachnoid hemorrhage. Surgical and endovascular interventions, such as external ventricular drain placement, aneurysm clipping, and endovascular coiling, have been developed over the past few decades. Patients with aneurysmal subarachnoid hemorrhage are also at risk for cerebral vasospasm and delayed cerebral ischemia. This article describes the diagnosis and treatment of aneurysmal subarachnoid hemorrhage, vasospasm, and cerebral ischemia. Concurrent medical considerations and ideas for future neuroinflammatory vasospasm research are also discussed.

Short-Term Outcome of Clipping Versus Coiling of Ruptured Intracranial Aneurysms Treated by Dual-Trained Cerebrovascular Surgeon: Single-Institution Experience.

OBJECTIVE: Studies that showed endovascular coiling of ruptured intracranial aneurysms (RAs) to be superior to microsurgical clipping have compared dedicated endovascular interventionists versus open cerebrovascular surgeons. This is the first study to evaluate outcomes of coiling versus clipping of RAs treated by a dual-trained cerebrovascular surgeon using a specific intervention protocol. METHODS: The prospectively maintained database was reviewed for all patients with RAs undergoing endovascular coiling (± stenting) or clipping by the senior author (dual-trained vascular neurosurgeon) between July 2010 and April 2015. RESULTS: Of the 252 patients identified, 70 underwent clipping and 182 underwent endovascular treatment. The mean and median time to last follow-up were 179.6 and 176.5 days in the endovascular cohort and 203.9 and 154.0 days in the surgical cohort. There was no difference in age, gender, World Federation of Neurosurgical Societies grade and Fisher grade, mean aneurysm size, and length of stay in the hospital/intensive care unit. Clipping had a higher proportion of middle cerebral artery aneurysms (37.1% vs. 8.8%; P < 0.001) and a lower proportion of aneurysms in the remaining locations (P < 0.001). 34.5% of the endovascular cohort and 32.9% of the clipping cohort were discharged home. There was no difference in modified Rankin Scale score at first or latest follow-up. Most had no significant disability. Mortality of endovascular treatment was 13.2% compared with 10.0% in clipping, and 16.5% versus 18.6% at the latest follow-up (both nonsignificant). The rate of conversion from coiling to clipping was 25.0%. CONCLUSIONS: RA treatment should be individualized, with clipping and coiling being 2 complementary arms. Assessment of patient and aneurysm characteristics along with the advantages of both techniques provides an optimal therapeutic modality.

Picking the good apples: statistics versus good judgment in choosing stent operators for a multicenter clinical trial.

BACKGROUND AND PURPOSE: The Carotid Revascularization Endarterectomy Versus Stenting Trial was completed with a low stroke and death rate. A lead-in series of patients receiving carotid artery stenting was used to select the physician-operators for the study, where performance was evaluated by complication rates and by peer review of cases. Herein, we assess the potential contribution of statistical evaluation of complication rates. METHODS: The ability to discriminate between stent operators who can successfully meet the published guideline of <3% combined rate of stroke and death is calculated under the binomial distribution, based on a small consecutive case series (n=24 patients). RESULTS: A criterion of ≤2 stroke or death events among the 24 patients (<8% event rate) was required of operators. Setting such a high criterion, however, ensures an inability to exclude operators who cannot meet the criteria. In fact, if a good operator is defined as having a 2% event rate and a poor operator as a 6% event rate, even a series of 240 patients would (on average) still exclude 5.4% of the good operators and include 4.6% of the poor operators. CONCLUSIONS: The low periprocedural event rates in the trial suggest success in separating skillful operators from less skillful. However, it seems unlikely that statistical assessment of event rates in the lead-in contributed to successful selection, but rather successful selection was more likely because of peer review of subjective and other factors including patient volume and technical approaches. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00004732.

Predictors of functional dependence despite successful revascularization in large-vessel occlusion strokes.

BACKGROUND AND PURPOSE: High revascularization rates in large-vessel occlusion strokes treated by mechanical thrombectomy are not always associated with good clinical outcomes. We evaluated predictors of functional dependence despite successful revascularization among patients with acute ischemic stroke treated with thrombectomy. METHODS: We analyzed the pooled data from the Multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI), Thrombectomy Revascularization of Large Vessel Occlusions in Acute Ischemic Stroke (TREVO), and TREVO 2 trials. Successful revascularization was defined as thrombolysis in cerebral infarction score 2b or 3. Functional dependence was defined as a score of 3 to 6 on the modified Rankin Scale at 3 months. We assessed relationship of demographic, clinical, angiographic characteristics, and hemorrhage with functional dependence despite successful revascularization. RESULTS: Two hundred and twenty-eight patients with successful revascularization had clinical outcome follow-up. The rates of functional dependence with endovascular success were 48.6% for Trevo thrombectomy and 58.0% for Merci thrombectomy. Age (odds ratio, 1.04; 95% confidence interval, 1.02-1.06 per 1-year increase), National Institutes of Health Stroke Scale score (odds ratio, 1.08; 95% confidence interval, 1.02-1.15 per 1-point increase), and symptom onset to endovascular treatment time (odds ratio, 1.11; 95% confidence interval, 1.01-1.22 per 30-minute delay) were predictors of functional dependence despite successful revascularization. Symptom onset to reperfusion time beyond 5 hours was associated with functional dependence. All subjects with symptomatic intracranial hemorrhage had functional dependence. CONCLUSIONS: One half of patients with successful mechanical thrombectomy do not have good outcomes. Age, severe neurological deficits, and delayed endovascular treatment were associated with functional dependence despite successful revascularization. Our data support efforts to minimize delays to endovascular therapy in patients with acute ischemic stroke to improve outcomes. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00318071, NCT01088672, and NCT01270867.

Correlation of AOL recanalization, TIMI reperfusion and TICI reperfusion with infarct growth and clinical outcome.

OBJECTIVE: To understand how three commonly used measures of endovascular therapy correlate with clinical outcome and infarct growth. METHODS: Prospectively enrolled patients underwent baseline MRI and started endovascular therapy within 12 h of stroke onset. The final angiogram was given a primary arterial occlusive lesion (AOL) recanalization score (0-3), a Thrombolysis in Myocardial Infarction (TIMI) score (0-3) and a Thrombolysis in Cerebral Infarction (TICI) score (0-3). The scores were dichotomized into poor revascularization (AOL 0-2, TIMI 0-1 and TICI 0-2a) versus good revascularization (AOL 3, TIMI 2-3, TICI 2b-3). Patients were classified according to whether or not they had target mismatch (TMM). Good outcome was defined as a 90-day modified Rankin Scale score of 0-2. RESULTS: Endovascular treatment was attempted in 100. A good outcome was achieved in 57% of patients with a TICI score of 2b-3 and in 24% of patients with a TICI score of 0-2a (p=0.001). Patients with TIMI scores of 2-3 and an AOL score of 3 had lower rates of good outcome (44% and 47%, respectively), which were not significantly better than those with TIMI scores of 0-1 or AOL scores of 0-2. In patients with TMM, these rates of good outcome improved with all the scoring systems and were significantly better for TIMI and TICI scores. Patients with a TICI score of 2a had rates of good functional outcome and lesion growth which were not different from those with TICI scores of 0-1 but were significantly worse than those with TICI scores of 2b-3. CONCLUSIONS: TIMI 2-3 and TICI 2b-3 reperfusion scores demonstrated improved outcome in patients with tissue mismatch with a small infarct core and a larger hypoperfused region but AOL scores did not. Patients with a TICI score of 2a had a poorer outcome and more lesion growth than those with TICI scores of 2b-3.

Measuring competence development for performing high flow extracranial-to-intracranial bypass.

We report our experience with competence development in the performance of high flow extracranial-to-intracranial (HF EC-IC) bypass surgery because of the infrequency of, and hence potential exposure to, this challenging surgery. We reviewed the National Hospital Morbidity Database for the incidence of EC-IC bypass surgery as well as a prospectively collected database (institutional experience). The following were recorded from the institutional experience: graft occlusion, stenosis, disruption, distal ischaemia, surgical complications of the bypass leading to a modified Rankin Scale (mRS) score >2, and intraoperative cross-clamping time. The cross-clamping time was considered the total time that circulation may have been impaired, which included both the distal and proximal cross-clamping periods. The Australian national EC-IC bypass rate (of all bypass types) averaged 1.9 cases per 1,000,000 head of population annually. The institutional experience (170 cases) of high flow EC-IC bypass in this series was associated with 14.7% (95% confidence interval [CI] 10.1-20.9) of graft complications. Graft-specific complications leading to a mRS score >2 were 5.9% (95% CI 3.1-10.6). For the 83 patients where the cross-clamping time was known, the time of cross-clamping was 44 ± 14 min. We concluded that HF EC-IC bypasses are rarely performed procedures that challenge the development of surgical competence. Novel ways of developing and maintaining surgical skills are necessary, including simulation and laboratory experience.

Multisociety consensus quality improvement guidelines for intraarterial catheter-directed treatment of acute ischemic stroke, from the American Society of Neuroradiology, Canadian Interventional Radiology Association, Cardiovascular and Interventional Radiological Society of Europe, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, European Society of Minimally Invasive Neurological Therapy, and Society of Vascular and Interventional Neurology.

PURPOSE: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. It is intended that these benchmarks be used in a quality assurance program to assess and improve processes and outcomes in acute stroke revascularization. MATERIALS AND METHODS: Members of the writing group were appointed by the American Society of Neuroradiology, Canadian Interventional Radiology Association, Cardiovascular and Interventional Radiological Society of Europe, Society of Cardiac Angiography and Interventions, Society of Interventional Radiology, Society of NeuroInterventional Surgery, European Society of Minimally Invasive Neurological Therapy, and Society of Vascular and Interventional Neurology. The writing group reviewed the relevant literature from 1986 through February 2012 to create an evidence table summarizing processes and outcomes of care. Performance metrics and thresholds were then created by consensus. The guideline was approved by the sponsoring societies. It is intended that this guideline be fully updated in 3 years. RESULTS: In this international multispecialty document, quality benchmarks for processes of care and clinical outcomes are defined. These include process measures of time to imaging, arterial puncture, and revascularization and measures of clinical outcome up to 90 days. CONCLUSIONS: Quality improvement guidelines are provided for endovascular acute ischemic stroke revascularization procedures.

The SPEED study: initial clinical evaluation of the Penumbra novel 054 Reperfusion Catheter.

BACKGROUND AND PURPOSE: Revascularization of acute ischemic stroke from a large vessel occlusion continues to be a challenge with current thrombectomy devices. The purpose of the SPEED study was to report the safety and effectiveness of the Penumbra 054 Reperfusion Catheter System in revascularizing large vessel occlusions. METHODS: In this retrospective multicenter study, data were collected from patients with angiographic evidence of large vessel occlusion treated with the Penumbra 054 device as the intended primary therapy. Clinical outcome data were collected with 90-day follow-up and the results were compared with those from the Penumbra Pivotal trial. RESULTS: Eighty-seven target vessels in 86 consecutive patients treated with the Penumbra 054 device were included. The Thrombolysis In Myocardial Infarction (TIMI) 2 or 3 revascularization rate was 91% compared with a reported 82% in the Penumbra Pivotal trial. This was accomplished in a median time of 20 min compared with 45 min in the Penumbra Pivotal trial (p<0.0001). Eighteen (21%) patients experienced an intracranial hemorrhage of which 12 (14%) were symptomatic. Good neurologic outcome (modified Rankin scores ≤ 2) at 90-day follow-up was achieved in 34.9% of patients compared with 25% reported in the Penumbra Pivotal trial. All-cause mortality was 25.6%. CONCLUSIONS: These results suggest that the Penumbra 054 is a fast, safe and effective revascularization tool for patients experiencing ischemic stroke secondary to large vessel occlusive disease. Improvements in speed and effectiveness of revascularization probably contributed to improved outcomes.

Developing practice recommendations for endovascular revascularization for acute ischemic stroke.

Guidelines have been established for the management of acute ischemic stroke; however, specific recommendations for endovascular revascularization therapy are lacking. Burgeoning investigation of endovascular revascularization therapies for acute ischemic stroke, rapid device development, and a diverse training background of the providers performing the procedures underscore the need for practice recommendations. This review provides a concise summary of the Society of Vascular and Interventional Neurology endovascular acute ischemic stroke roundtable meeting. This document was developed to review current clinical efficacy of pharmacologic and mechanical revascularization therapy, selection criteria, periprocedure management, and endovascular time metrics and to highlight current practice patterns. It therefore provides an outline for the future development of multisociety guidelines and recommendations to improve patient selection, procedural management, and organizational strategies for revascularization therapies in acute ischemic stroke.

Bypass surgery for moyamoya disease: concept and essence of sugical techniques.

This review describes the basic concepts of surgical revascularization for moyamoya disease, including direct and indirect bypass surgery. Direct bypass surgery can improve cerebral hemodynamics and reduce further ischemic events immediately after surgery, but may be technically challenging in some pediatric patients. Indirect bypass surgery is simple and has widely been used. However, its beneficial effects can be achieved 3 to 4 months after surgery, and surgical design is quite important to determine the extent of surgical collateral pathways. Combined bypass procedure, especially superficial temporal artery (STA) to middle cerebral artery anastomosis and indirect bypass, encephalo-duro-myo-arterio-pericranial synangiosis, is a safe and effective option to improve the short- and long-term outcome in patients with moyamoya disease. Alternative techniques are also described for specific cases with profound cerebral ischemia in the anterior cerebral artery or posterior cerebral artery territory. Special techniques to safely complete bypass surgery and avoid perioperative complications are presented, including methods to prevent delayed wound healing, to avoid facial nerve palsy after surgery, and to preserve the STA and middle meningeal artery during skin incision and craniotomy. Finally, the importance of careful management of patients is emphasized to reduce the incidence of perioperative complications, including ischemic stroke and hyperperfusion syndrome.