Challenges to Widespread Implementation of Stroke Thrombectomy.

Endovascular treatment (EVT) for acute ischemic stroke is one of the most efficacious and effective treatments in medicine, yet globally, its implementation remains limited. Patterns of EVT underutilization exist in virtually any health care system and range from a complete lack of access to selective undertreatment of certain patient subgroups. In this review, we outline different patterns of EVT underutilization and possible causes. We discuss common challenges and bottlenecks that are encountered by physicians, patients, and other stakeholders when trying to establish and expand EVT services in different scenarios and possible pathways to overcome these challenges. Lastly, we discuss the importance of implementation research studies, strategic partnerships, and advocacy efforts to mitigate EVT underutilization.

Seasonal variations in stroke occurrence.

Background Understanding seasonal variations in stroke can help stakeholders identify underlying causes in seasonal trends, and tailor resources appropriately to times of highest needs. We sought to evaluate seasonal occurrence of stroke and its subtypes. Methods We conducted a retrospective cohort study using administrative data from January 1st, 2003, to December 31st, 2017, in Ontario, Canada's most populous province. We evaluated seasonal variations in stroke occurrence by subtype, via age/sex standardized rates and adjusted rate ratios using Poisson regressions. In those with stroke, we evaluated 30-day case fatality risks by season, adjusted for age, sex, stroke type and comorbid conditions, and then used Cox proportional hazard models to estimate the effect of season on the fatality. The administrative data used in this study was from the Canadian Institute for Health Information's Discharge Abstract Database (DAD), the National Ambulatory Care Reporting System (NACRS) database, the Ontario Registered Persons Database, and from the 2006 and 2011 Canada Census and linked administrative databases. Results During our study period, we observed 394,145 stroke or TIA events, with a decrease in monthly hospitalization/emergency department visits per 100,000 people between January 2003 and December 2017 from 24.22 to 17.43. Compared to the summer, overall stroke occurrence was similar in the spring but slightly lower in the fall (adjusted relative risk (aRR) 0.97, 95% confidence interval (CI) 0.96 to 0.98) and winter (aRR 0.94, 95% CI 0.94 to 0.95). There were minor variations by stroke subtype. Winter was associated with the highest risk of stroke case fatality compared to the summer (12.4% vs. 11.4%, adjusted hazard ratio 1.10, 95% CI 1.07 to 1.13). Conclusions We found seasonal variations in stroke occurrence and case fatality, although the absolute differences were small. Further work is needed to better understand how environmental or meteorological factors might affect stroke risk.

Advance Consent in Acute Stroke Trials: Survey of Canadian Stroke Physicians.

Advance consent presents a potential solution to the challenge of obtaining informed consent for participation in acute stroke trials. Clinicians in stroke prevention clinics are uniquely positioned to identify and seek consent from potential stroke trial participants. To assess the acceptability of advance consent to Canadian stroke clinic physicians, we performed an online survey. We obtained 58 respondents (response rate 35%): the vast majority (82%) expressed comfort with obtaining advance consent and 92% felt that doing so would not be a significant disruption to clinic workflow. These results support further study of advance consent for acute stroke trials.

Advance Consent in Acute Stroke Trials: Survey of Canadian Research Ethics Board Chairs.

Advance consent could allow individuals at high risk of stroke to provide consent before they might become eligible for enrollment in acute stroke trials. This survey explores the acceptability of this novel technique to Canadian Research Ethics Board (REB) chairs that review acute stroke trials. Responses from 15 REB chairs showed that majority of respondents expressed comfort approving studies that adopt advance consent. There was no clear preference for advance consent over deferral of consent, although respondents expressed significant concern with broad rather than trial-specific advance consent. These findings shed light on the acceptability of advance consent to Canadian ethics regulators.

Ethical Problems of Observational Studies and Big Data Compared to Randomized Trials.

The temptation to use prospective observational studies (POS) instead of conducting difficult trials (RCTs) has always existed, but with the advent of powerful computers and large databases, it can become almost irresistible. We examine the potential consequences, were this to occur, by comparing two hypothetical studies of a new treatment: one RCT, and one POS. The POS inevitably submits more patients to inferior research methodology. In RCTs, patients are clearly informed of the research context, and 1:1 randomized allocation between experimental and validated treatment balances risks for each patient. In POS, for each patient, the risks of receiving inferior treatment are impossible to estimate. The research context and the uncertainty are down-played, and patients and clinicians are at risk of becoming passive research subjects in studies performed from an outsider's view, which potentially has extraneous objectives, and is conducted without their explicit, autonomous, and voluntary involvement and consent.

Nonaneurysmal perimesencephalic subarachnoid hemorrhage on noncontrast head CT: An accuracy, inter-rater, and intra-rater reliability study.

BACKGROUND AND PURPOSE: To evaluate the reliability and accuracy of nonaneurysmal perimesencephalic subarachnoid hemorrhage (NAPSAH) on Noncontrast Head CT (NCCT) between numerous raters. MATERIALS AND METHODS: 45 NCCT of adult patients with SAH who also had a catheter angiography (CA) were independently evaluated by 48 diverse raters; 45 raters performed a second assessment one month later. For each case, raters were asked: 1) whether they judged the bleeding pattern to be perimesencephalic; 2) whether there was blood anterior to brainstem; 3) complete filling of the anterior interhemispheric fissure (AIF); 4) extension to the lateral part of the sylvian fissure (LSF); 5) frank intraventricular hemorrhage; 6) whether in the hypothetical presence of a negative CT angiogram they would still recommend CA. An automatic NAPSAH diagnosis was also generated by combining responses to questions 2-5. Reliability was estimated using Gwet's AC1 (κG), and the relationship between the NCCT diagnosis of NAPSAH and the recommendation to perform CA using Cramer's V test. Multi-rater accuracy of NCCT in predicting negative CA was explored. RESULTS: Inter-rater reliability for the presence of NAPSAH was moderate (κG = 0.58; 95%CI: 0.47, 0.69), but improved to substantial when automatically generated (κG = 0.70; 95%CI: 0.59, 0.81). The most reliable criteria were the absence of AIF filling (κG = 0.79) and extension to LSF (κG = 0.79). Mean intra-rater reliability was substantial (κG = 0.65). NAPSAH weakly correlated with CA decision (V = 0.50). Mean sensitivity and specificity were 58% (95%CI: 44%, 71%) and 83 % (95%CI: 72 %, 94%), respectively. CONCLUSION: NAPSAH remains a diagnosis of exclusion. The NCCT diagnosis was moderately reliable and its impact on clinical decisions modest.

Influence of Time of Admission on Endovascular Thrombectomy (EVT): Comparison of Outcomes During Business Hours Versus Off-Business Hours.

Purpose:To investigate the differences in endovascular thrombectomy (EVT) outcomes of patients treated for acute ischaemic stroke (AIS) during business versus off-business hours. Methods: A single-centre retrospective cohort study of patients with AIS treated with EVT from February 1, 2015, to May 31, 2021, was performed at a comprehensive stroke centre (CSC). Patients were divided into business (Monday to Friday, 8 AM-5 PM) versus off-business hours groups. The primary outcome was functional neurological disability, scored using the modified Rankin Scale (mRS) at 90 days. Secondary outcomes included the rate of successful reperfusion and procedural workflow time delays. Differences in proportions were assessed using Fisher's exact and Chi-Square tests as appropriate. For continuous variables, differences in medians between groups were assessed using Mann-Whitney U tests. Results: A total of 676 patients were included, with 399 patients (59%) comprising the off-business-hour group. No significant differences were seen in age, sex, ASPECTS score, or NIHSS at arrival. Off-business hours strokes had a longer delay between CSC arrival to groin puncture (minutes: 81 vs 44, P < .0001) and between imaging to groin puncture (minutes: 67 vs 32, P < .0001) compared to the business hours strokes. There were no differences in the rate of successful reperfusion (mTICI ≥2b) between groups (82% vs 83%, P = .61). At 90 days, 65% of patients in both groups had an mRS ≤2 (P = .91). Conclusion: Despite workflow delays in initiating EVT during off-business hours, there were no differences in the rate of successful reperfusion or functional outcomes.

Distal to proximal snaring of a fractured microcatheter during dural AVF embolization.

Detachable-tip microcatheters are frequently used for endovascular embolization of arteriovenous shunts. Occasionally, the detachable tip can break during navigation resulting in the loss of the microcatheter tip in a vessel, which can lead to thrombo-embolic complications and also limit further navigation into the vessel to complete treatment. We present a case of dural AV-fistula embolization that was complicated by the accidental detachment and loss of the tip of a microcatheter during navigation to injection site. The proximal tip of the broken catheter was not visible and therefore we were unable to capture its proximal part with a Snare. Ultimately, we navigated a microcatheter distal to the broken segment and successfully snared the microcatheter fragment retrogradely. (Video 1).

First-Pass Effect in Basilar Artery Occlusions: Insights From the Endovascular Treatment of Ischemic Stroke Registry.

BACKGROUND AND PURPOSE: In the settings of thrombectomy, the first-pass effect (FPE), defined by a complete recanalization after one pass with no rescue therapy, has been shown to be associated with an improved outcome. As this phenomenon has been predominantly described in anterior circulation strokes, we aimed to study the prevalence, outcomes, and predictors of FPE in patients with a basilar artery occlusion. METHODS: From a prospective multicentric registry, we collected the data of all consecutive basilar artery occlusion patients who underwent thrombectomy and compared the outcomes of patients who achieved FPE and those who did not. We also compared FPE patients with those who achieved a complete recanalization with >1 pass. Finally, a multivariate analysis was performed to determine the predictors of FPE. RESULTS: Data from 280 patients were analyzed in our study, including 84 of 280 patients (30%) with an atheromatous etiology. An FPE was achieved in 93 patients (33.2%), with a significantly higher proportion of good outcomes (modified Rankin Scale score 0-2 at 3 months) and lower mortality than non-FPE patients. An FPE was also associated with improved outcomes compared with patients who went on to have full recanalization with >1 pass. Contact aspiration as first-line strategy was a strong predictor of FPE, whereas baseline antiplatelets and atheromatous etiology were negative predictors. CONCLUSIONS: In our study, an FPE was achieved in approximately one-third of patients with a basilar artery occlusion and was associated with improved outcomes. More research is needed to improve devices and techniques to increase the incidence of FPE. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03776877.

Angiographic results of surgical or endovascular treatment of intracranial aneurysms: a systematic review and inter-observer reliability study.

PURPOSE: Results of surgical or endovascular treatment of intracranial aneurysms are often assessed using angiography. A reliable method to report results irrespective of treatment modality is needed to enable comparisons. Our goals were to systematically review existing classification systems, and to propose a 3-point classification applicable to both treatments and assess its reliability. METHODS: We conducted two systematic reviews on classification systems of angiographic results after clipping or coiling to select a simple 3-category scale that could apply to both treatments. We then circulated an electronic portfolio of angiograms of clipped (n=30) or coiled (n=30) aneurysms, and asked raters to evaluate the degree of occlusion using this scale. Raters were also asked to choose an appropriate follow-up management for each patient based on the degree of occlusion. Agreement was assessed using Krippendorff's α statistics (αK), and relationship between occlusion grade and clinical management was analyzed using Fisher's exact and Cramer's V tests. RESULTS: The systematic reviews found 70 different grading scales with heterogeneous reliability (kappa values from 0.12 to 1.00). The 60-patient portfolio was independently evaluated by 19 raters of diverse backgrounds (neurosurgery, radiology, and neurology) and experience. There was substantial agreement (αK=0.76, 95%CI, 0.67-0.83) between raters, regardless of background, experience, or treatment used. Intra-rater agreement ranged from moderate to almost perfect. A strong relationship was found between angiographic grades and management decisions (Cramer's V: 0.80±0.12). CONCLUSION: A simple 3-point scale demonstrated sufficient reliability to be used in reporting aneurysm treatments or in evaluating treatment results in comparative randomized trials.

Decreased Stroke Presentation Rates at a Comprehensive Stroke Center during COVID-19.

We reviewed stroke care delivery during the COVID-19 pandemic at our stroke center and provincial telestroke system. We counted referrals to our prevention clinic, code strokes, thrombolysis, endovascular thrombectomies, and activations of a provincial telestroke system from February to April of 2017-2020. In April 2020, there was 28% reduction in prevention clinic referrals, 32% reduction in code strokes, and 26% reduction in telestroke activations compared to prior years. Thrombolysis and endovascular thrombectomy rates remained constant. Fewer patients received stroke services across the spectrum from prevention, acute care to telestroke care in Ontario, Canada, during the COVID-19 pandemic.

Comparing N-hexyl cyanoacrylate (Magic Glue) and N-butyl cyanoacrylate (NBCA) for neurovascular embolization using the pressure cooker technique: An experimental study in swine.

BACKGROUND: The pressure cooker (PC) technique uses a second microcatheter to produce a proximal occlusion to prevent the reflux of liquid embolic agent (LEA) injected through a more distal microcatheter, and can be used to treat arteriovenous malformations and dural arteriovenous fistulae. The liquid embolic Magic Glue (MG) (N-hexyl cyanoacrylate (NHCA)) has been introduced as an alternative to N-butyl cyanoacrylate (NBCA). Our goals were to compare the extent of embolization of rete mirabile with or without the PC technique using NBCA or MG, and to compare the proximal occlusions obtained with MG or NBCA while using the PC technique in a renal arterial model. METHODS: Rete mirabile were embolized with (n = 4) and without (n = 4) the PC technique, using MG (n = 4) or NBCA (n = 4). A renal arterial model was then used to study the characteristics of the MG plug (n = 10) used for the PC technique, and resistance to catheter withdrawal as compared to NBCA (n = 4). Specimens were analyzed macro- and microscopically and compared to angiographic results. RESULTS: Extent of rete embolization with CYA agents was not significantly greater when using the PC technique. Results were similar with both types of cyanoacrylate (p = 0.657). The force necessary to withdraw the microcatheter was less with MG than with NBCA (p = 0.035). CONCLUSION: MG was similar to NBCA in extent of rete embolization. Less traction force was necessary to withdraw trapped non-detachable microcatheters using MG compared to NBCA.

Diffusion-Weighted-Imaging infarct volume measurement tools show discrepancies leading to diverging thrombectomy decisions.

BACKGROUND AND PURPOSE: Recent clinical trials demonstrated the benefit of thrombectomy beyond 6h based on the automated measurement of infarct volume exclusively with the RAPID software. We aimed to compare eight tools commonly used for the measurement of infarct volume and see whether they would lead to similar thrombectomy decisions based on the Diffusion-weighted-imaging or computerized-tomography-perfusion Assessment with clinical mismatch in the triage of Wake-up and late-presenting strokes undergoing Neurointervention with Trevo (DAWN) trial imaging inclusion criteria. MATERIALS AND METHODS: The diffusion-weighted-imaging (DWI) infarct volume of 36 patients was measured with 3 automated tools (including RAPID) and 5 non-automated tools. The agreement for the measurements of DWI infarct volume and the resulting thrombectomy decisions were assessed with intraclass correlation coefficient (ICC) and Fleiss' Kappa (K) statistics. RESULTS: The correlation for the measurement of DWI infarct volume between all 9 tools was excellent (ICC>0.8). After dichotomization, agreement was substantial for any of the cut-points used in DAWN trial. Discrepancies involving at least one of the tools for thrombectomy decisions based on DAWN criteria occurred in one third of cases. Compared with RAPID, the use of any other tool for treatment decision based on DAWN criteria would have led to contradictory decisions in 6% to 19% of cases. CONCLUSION: There are several currently available tools for the measurement of DWI infarct volume with excellent correlation. Despite the high agreement demonstrated in our study, frequent discrepancies between measurements in some dichotomized configurations led to frequent diverging thrombectomy decisions when applying DAWN criteria.

Effect of Steady and Dynamic Blood Pressure Parameters During Thrombectomy According to the Collateral Status.

Background and Purpose- Guidelines regarding blood pressure (BP) management during endovascular therapy (EVT) for anterior circulation strokes are questionable since the optimal BP target is a matter of debate. To evaluate the importance of hemodynamic control during EVT, we investigated the impact of dynamic and steady BP parameters during EVT on functional outcome (part 1) and according to the collateral status (CS; part 2). Methods- We performed a post hoc analysis of the ASTER trial (Contact Aspiration Versus Stent Retriever for Successful Recanalization). BP was measured noninvasively during EVT and CS assessed on the angiographic run before EVT. We studied dynamic BP parameter using BP variability (coefficient of variation) and steady BP parameter (hypotension time defined as systolic BP <140 mm Hg and mean arterial pressure <90 mm Hg). The primary outcome was favorable outcome defined as a 3-month modified Rankin Scale score between 0 and 2. Results- Among the 381 patients of the ASTER study, 172 patients were included in part 1 and 159 in part 2. Systolic BP, diastolic BP, and mean arterial pressure variability were negatively associated with favorable outcome regardless of CS: per 10-unit increase, adjusted odds ratios were 0.45 (95% CI, 0.20-0.98), 0.37 (95% CI, 0.19-0.72), and 0.35 (95% CI, 0.16-0.76), respectively. According to CS, the hypotension time with periprocedural mean arterial pressure <90 mm Hg was negatively associated with favorable outcome in patients with poor CS (adjusted odds ratio, 0.88 [95% CI, 0.72-1.09]) but not in patients with good CS (adjusted odds ratio, 1.24 [95% CI, 0.91-1.67]; Phet=0.047). Conclusions- The CS did not modify the association between dynamic parameters and functional outcomes, but some findings suggest that the CS modifies the association between steady parameter and functional outcomes. Hypotension time according to the CS was not statistically predictive of poor outcomes but displayed a trend toward worse outcomes for patients with poor CS only.

Safety and effectiveness of cervical vertebroplasty: report of a large cohort and systematic review.

PURPOSE: To evaluate retrospectively safety and effectiveness of cervical vertebroplasty (cVP) based on a single-center large cohort. MATERIALS AND METHODS: All cVP performed at a single center from January 2001 to October 2014 were included and reviewed. Procedure-related complications (minor and major) were systematically recorded. Effectiveness in terms of analgesia was evaluated using a semi-quantitative grading scale at 1-month follow-up. Risk factors for the occurrence of a procedure-related complication or cement leakage, as well as factors influencing pain relief at 1-month follow-up, were evaluated using a multivariate analysis. RESULTS: One hundred and forty cVP procedures (176 vertebrae) were performed in 130 consecutive patients (88 female, 42 male; mean age = 56 years) during the inclusion period. Among the treated lesions, 80% were bone metastases (mostly from breast cancer), 8% were related to hematological malignancies, and 12% were non-malignant lesions. One fatal complication (0.7%) was related to cement migration in the vertebrobasilar system. Three cervical hematomas were recorded, one of them requiring prolonged oral intubation. The overall rate of major complications was 1.5%. At 1 month, pain reduction was observed in 76% of the cases. Additional surgical fixation was required in 6.1% of the cases. cVP of more than one vertebra during the same session was an independent risk factor for procedure-related complications. CONCLUSION: Cervical vertebroplasty is a safe technique with an acceptable major complication rate. Its effectiveness in terms of pain relief is good at mid-term follow-up. KEY POINTS: • Cervical vertebroplasty (cVP) is a safe procedure with a low rate of major complications (1.5%). • cVP provides pain relief in 76% of the cases. • Additional fixation surgery is rarely required after cVP (6.1% of the cases).

Measuring clinical uncertainty and equipoise by applying the agreement study methodology to patient management decisions.

BACKGROUND: Clinical uncertainty and equipoise are vague notions that play important roles in contemporary problems of medical care and research, including the design and conduct of pragmatic trials. Our goal was to show how the reliability study methods normally used to assess diagnostic tests can be applied to particular management decisions to measure the degree of uncertainty and equipoise regarding the use of rival management options. METHODS: We first use thrombectomy in acute stroke as an illustrative example of the method we propose. We then review, item by item, how the various design elements of diagnostic reliability studies can be modified in order to measure clinical uncertainty. RESULTS: The thrombectomy example shows sufficient disagreement and uncertainty to warrant the conduct of additional randomized trials. The general method we propose is that a sufficient number of diverse individual cases sharing a similar clinical problem and covering a wide spectrum of clinical presentations be assembled into a portfolio that is submitted to a variety of clinicians who routinely manage patients with the clinical problem. DISCUSSION: Clinicians are asked to independently choose one of the predefined management options, which are selected from those that would be compared within a randomized trial that would address the clinical dilemma. Intra-rater agreement can be assessed at a later time with a second evaluation. Various professional judgments concerning individual patients can then be compared and analyzed using kappa statistics or similar methods. Interpretation of results can be facilitated by providing examples or by translating the results into clinically meaningful summary sentences. CONCLUSIONS: Measuring the uncertainty regarding management options for clinical problems may reveal substantial disagreement, provide an empirical foundation for the notion of equipoise, and inform or facilitate the design/conduct of clinical trials to address the clinical dilemma.

Benefits and Safety of Periprocedural Heparin During Thrombectomy in Patients Contra-Indicated for Alteplase.

BACKROUND AND PURPOSE: Role of peri-procedural heparin as an adjuvant treatment during mechanical thrombectomy (MT) for patients contra-indicated for alteplase remains a source of debate. METHODS: We included patients from the multicenter French register ETIS that underwent MT without administration of alteplase, and compared patients who received heparin during MT with patients who did not. Heparin impact on outcome were analyzed regarding final TICI score, NIHSS at day one, modified rankin scale (mRS) and intracranial hemorrhagic transformation on imaging at day one. RESULTS: Over 1031 patients, 751 were included between January 2015 and June 2018 in 6 different centers, and 223 (26.69%) received heparin. Heparin administration was associated with a significant deleterious effect on NIHSS at 24h [adjusted OR = 1.2; p = 0.02], mRS at 3 months [adjusted OR 1.58; p = 0.03], and on complete reperfusion [TICI 3 adjusted OR 0.68; p = 0.02]. Heparin administration was associated with a significant reduction of hemorrhagic transformation [adjusted OR 0.48; p = 0.00005]. CONCLUSIONS: Heparin administration during MT seems deleterious for reperfusion and functional outcome. Randomized trials are needed to identify the role of antithrombotic treatments, such as heparin, in the setting of acute ischemic stroke management.

Outcome and recanalization rate of tandem basilar artery occlusion treated by mechanical thrombectomy.

BACKGROUND: Tandem basilar artery occlusions (tBAO) are defined as concomitant basilar artery and extracranial dominant vertebral artery occlusions. The prognosis of such tBAO treated by mechanical thrombectomy (MT) has been scantly reported. The purpose of our study was to compare the safety and effectiveness of MT for patients with tBAO compared to those with non-tandem basilar artery occlusions (ntBAO). PATIENTS AND METHODS: Retrospective analysis of a database of patients who underwent MT at two academic centres. All patients treated for BAO were retrieved. Patients with tBAO, defined as a concomitant BAO and extracranial vertebral artery (VA) occlusion or severe stenosis ≥70% (V1 or proximal V2 segment) were compared with patients with ntBAO. RESULTS: A total of 15 patients with tBAO and 74 patients with ntBAO were enrolled. Successful reperfusion (modified thrombolysis in cerebral infarction score ≥2b) was obtained in 73.3% versus 90.5% (OR = 0.29, 95%CI: 0.07-1.15), good clinical outcome (3-months modified Rankin scale ≤2) was reached by 26.7% versus 32.4% (OR = 0.76; 95% CI: 0.24-2.63) and mortality at 3-months was 46.7% versus 31% (OR = 1.94; 95%CI: 0.63-6) of patients with tBAO versus ntBAO, respectively. Two patients (13.3%) with tBAO and three (4%) with ntBAO had symptomatic intracranial haemorrhage (OR = 3.64; 95% CI: 0.55-24). CONCLUSION: Mechanical thrombectomy for patients with tandem basilar artery occlusion tends to be associated with lower rates of successful reperfusion and good clinical outcome, and higher rate of mortality. Larger multicentre studies are warranted to better precise the proper selection and management of such patients.

Association of Blood Pressure During Thrombectomy for Acute Ischemic Stroke With Functional Outcome: A Systematic Review.

Background and Purpose- Optimal blood pressure (BP) targets during mechanical thrombectomy (MT) for acute ischemic stroke (AIS) are unknown, and randomized controlled trials addressing this issue are lacking. We aimed to perform a systematic review of studies evaluating the influence of periprocedural BP on functional outcome after MT. Methods- Studies assessing periprocedural BP effect on functional outcome published after January 1st, 2012 were included in the systematic review. The PRISMA checklist and flow diagram were followed for the design and reporting of this work. Results- Nine studies were included, for a total of 1037 patients. The heterogeneity in findings with respect to BP monitoring and studied parameters precluded a meta-analysis. Mean arterial pressure was the most frequently reported parameter to describe BP variability during MT, and systolic BP was the main parameter used to define periprocedural BP targets. Five studies suggested an association between 3 types of BP drops as predictors of poor functional outcome at 3 months: >40% drop in mean arterial pressure compared with baseline (odds ratio=2.8; [1.09-7.19]; P=0.032), lowest mean arterial pressure before recanalization (odds ratio=1.28; [1.01-1.62] per 10 mm Hg drop below 100 mm Hg; P=0.04), and MAP drops (odds ratio=4.38; [1.53-12.6] for drops >10%). Four studies did not show an association between BP during MT and functional outcome, including 3 studies with strict periprocedural systolic BP targets (within a 140-180 mm Hg). Conclusions- BP drops during MT may be associated with a worse functional outcome. When strict systolic BP targets are achieved, no association between BP and functional outcome was also noted. Both conclusions require further evaluation in randomized studies.

Predictors of Parenchymal Hematoma After Mechanical Thrombectomy: A Multicenter Study

Background and Purpose: Parenchymal hematoma (PH) is a rare but dreadful complication of acute ischemic stroke with unclear underlying mechanisms. We aimed to study the incidence and predictors of PH after mechanical thrombectomy. Methods: Data from a prospective observational multicenter registry was screened to identify acute ischemic stroke patients with an anterior circulation large vessel occlusion who underwent mechanical thrombectomy. Clinical, imaging, and procedural characteristics were used for the analysis, including brain imaging systematically performed at 24 hours. PH occurrence was assessed according to ECASS (European Collaborative Acute Stroke Study) criteria. Univariate and multivariable analyses were performed to identify predictors of PH. Results: A total of 1316 patients were included in the study. PH occurred in 153 out of 1316 patients (11.6%) and was associated with a lower rate of favorable outcome and increased mortality. On multivariable analysis, age (per 1 year increase, odds ratio [OR], 1.01; 95% CI, 1.00­1.03; P=0.05), current smoking (OR, 2.02; 95% CI, 1.32­3.09; P<0.01), admission Alberta Stroke Program Early CT Score (per a decrease of 1 point, OR, 1.70; 95% CI, 1.18­2.44; P<0.01), general anesthesia (OR, 1.98; 95% CI, 1.36­2.90; P<0.001), angiographic poor collaterals (OR, 2.13; 95% CI, 1.36­3.33; P<0.001) and embolization in new territory (OR, 2.94; 95% CI, 1.70­5.10; P<0.001) were identified as independent predictors of PH. Conclusions: PH occurred at a rate of 11.6% after mechanical thrombectomy, with high morbidity and mortality. Our study identified clinical, radiological, and procedural predictors of PH occurrence that can serve as the focus of future periprocedural management studies with the aim of reducing its occurrence.