An international multicenter retrospective study to survey the landscape of thrombectomy in the treatment of anterior circulation acute ischemic stroke: outcomes with respect to age

Predictors of mTICI 2c/3 over 2b in patients successfully recanalized with mechanical thrombectomy

OBJECTIVE

For patients presenting with acute ischemic stroke (AIS) caused by large vessel occlusions (LVO), mechanical thrombectomy (MT) is the treatment standard of care in eligible patients. Modified Thrombolysis in Cerebral Infarction (mTICI) grades of 2b, 2c, and 3 are all considered successful reperfusion; however, recent studies have shown achieving mTICI 2c/3 leads to better outcomes than mTICI 2b. This study aims to investigate whether any baseline preprocedural or periprocedural parameters are predictive of achieving mTICI 2c/3 in successfully recanalized LVO patients.

METHODS

We conducted a retrospective multicenter cohort study of consecutive patients presenting with AIS caused by a LVO from 1 January 2017 to 1 January 2023. Baseline and procedural data were collected through chart review. Univariate and multivariate analysis were applied to determine significant predictors of mTICI 2c/3.

RESULTS

A total of 216 patients were included in the study, with 159 (73.6%) achieving mTICI 2c/3 recanalization and 57 (26.4%) achieving mTICI 2b recanalization. We found that a higher groin puncture to first pass time (OR = 0.976, 95%CI: 0.960-0.992, p = 0.004), a higher first pass to recanalization time (OR = 0.985, 95%CI: 0.972-0.998, p = 0.029), a higher admission NIHSS (OR = 0.949, 95%CI: 0.904-0.995, p = 0.031), and a lower age (OR = 1.032, 95%CI: 1.01-1.055, p = 0.005) were associated with a decreased probability of achieving mTICI 2c/3.

INTERPRETATION

A lower groin puncture to first pass time, a lower first pass to recanalization time, a lower admission NIHSS, and a higher age were independent predictors of mTICI 2c/3 recanalization.

The negative effect of aging on cerebral venous outflow in acute ischemic stroke

Cortical venous outflow (VO) represents an imaging biomarker of increasing interest in patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO). We conducted a retrospective multicenter cohort study to investigate the effect of aging on VO. A total of 784 patients met the inclusion criteria. Cortical Vein Opacification Score (COVES) was used to assess VO profiles on admission CT angiography. Cerebral microperfusion was determined using the hypoperfusion intensity ratio (HIR) derived from perfusion imaging. Arterial collaterals were assessed using the Tan scale. Multivariable regression analysis was performed to identify independent determinants of VO, HIR and arterial collaterals. In multivariable regression, higher age correlated with worse VO (adjusted odds ratio [95% CI]; 0.83 [0.73-0.95]; P = 0.006) and poorer HIR (β coefficient [95% CI], 0.014 [0.005-0.024]; P = 0.002). The negative effect of higher age on VO was mediated by the extent of HIR (17.3%). We conclude that higher age was associated with worse VO in AIS-LVO, partially explained by the extent of HIR reflecting cerebral microperfusion. Our study underlines the need to assess collateral blood flow beyond the arterial system and provides valuable insights into deteriorated cerebral blood supply in elderly AIS-LVO patients.

Impact of age on mechanical thrombectomy and clinical outcome in patients with acute ischemic stroke

BACKGROUND AND PURPOSE

Mechanical thrombectomy is less effective in patients aged 80 years or older. Our goal was to better understand the impact of age in general on recanalization rates and clinical outcome.

METHODS

We performed a retrospective analysis of our prospective database of adult patients with acute ischemic stroke due to large vessel occlusions, who had undergone mechanical thrombectomy between 2019 and mid-2021. The cohort was categorized into five age groups: 18 - 49, 50 - 59, 60 - 69, 70 - 79 and ≥ 80 years. Our primary outcome measure was clinical outcome at three months after mechanical thrombectomy, measured by the mRS score. Secondary outcomes were procedure times and rates of successful recanalization, defined by mTICI ≥ 2b.

RESULTS

Data of 264 patients were analyzed. There were no significant differences in procedure times (p = 0.46) or in rates of successful recanalization (p = 0.49) between age groups. There was a significant association of age and mRS score at three months (p < 0.0001): From youngest to oldest group, odds of functional independence (mRS ≤ 2) decreased (80.0% vs. 21.3%) and odds of death (mRS 6) increased (13.3% vs. 57.3%). Increasing age was significantly associated with lower rates of functional independence (OR 0.93; [95% CI 0.90 - 0.95]), higher rates of care dependency (OR 1.04; [95% CI 1.01 - 1.07]) and higher mortality rates (OR 1.06; [95% CI 1.04 - 1.09]).

CONCLUSION

Higher age had no significant impact on recanalization times or recanalization rates but was strongly associated with worse clinical outcome after mechanical thrombectomy.

Strokes and Predictors of Outcomes

Stroke is a leading cause of long-term disability and fifth leading cause of death. Acute ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, the 3 subtypes of strokes, have varying treatment modalities. Common themes in management advocate for early interventions to reduce morbidity and mortality but not all perception is supported through randomized controlled trials. Each stroke subtype has varying premorbid-related and ictus-related outcome predictive models that have differing sensitivities and specificities.

Effect of blood pressure on the prognosis of acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization

PURPOSE

To explore the effect of blood pressure on the prognosis of acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization.

METHODS

Acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization were retrospectively collected. All patients were divided into the functional independent group and non-functional independent group, death group and non-death group based on the 90-day mRS score. Logistic regression was applied to analyze the relationship between the highest systolic blood pressure, the average systolic blood pressure, the lowest systolic blood pressure, the highest diastolic blood pressure, the average diastolic blood pressure, the lowest diastolic blood pressure in the first 24 h after admission and the functional prognosis as well as the complications after 90 days. The independent impact factors selected from regression analysis were used to investigate the blood pressure with prognostic value by receiver operating characteristic curve (ROC).

RESULTS

A total of 70 patients were recruited in this study. Among them, 39 cases (55.71%) were male and 31 cases (44.29%) were female, with a mean age of 61.83 ± 15.24 years old. 15 cases (21.43%) had a favorable 90-day outcome, and the other 55 cases (78.57%) had a higher mRS Score. After a 90-day follow-up, univariate analysis showed that hypertension and hyperlipidemia, highest systolic blood pressure, mean systolic blood pressure and NIHSS score were statistically significant in two groups with or without functional independence, while the NIHSS score at admission, systolic blood pressure at admission, average systolic blood pressure, highest systolic blood pressure and diastolic blood pressure were statistically significant in patients with death outcomes (P < 0.05). Multivariate regression analysis suggested that the highest systolic blood pressure was statistically significant (P < 0.05), the further ROC curve results showed the cut-off value of the highest systolic blood pressure was 180.5 mmHg, with a sensitivity of 82.35% and a specificity of 81.13%. The highest Youden's index was 0.6348.

CONCLUSION

For acute ischemic stroke patients caused by anterior circulation large vessel occlusion without recanalization, the appropriate reduction of blood pressure within 24 h after admission may have a positive effect on the clinical prognosis. The 90-day mortality of acute ischemic stroke patients without revascularization was independently related to the highest systolic blood pressure. The risk of death was increased when the highest systolic blood pressure was greater than 180.5 mmHg.

Thrombectomy in large vessel occlusion stroke-Does age matter?

OBJECTIVES

Endovascular treatment (EVT) is the gold standard treatment for emergent large vessel occlusion (LVO). The benefit of EVT for emergent LVO in elderly patients (>80 years old) is still debated as they have been under-represented in randomized controlled trials. Elderly patients with an emergent LVO are a growing population warranting further study.

MATERIALS & METHODS

We included 225 consecutive patients treated with EVT for LVO either in the anterior or posterior circulation. The clinical outcome was assessed using the National Institute of Health Stroke Scale (NIHSS). Long-term functional outcome was assessed using 90-day modified ranking scale (mRS).

RESULTS

Neurological improvement: A five-year higher age predicted a 0.43 higher mean NIHSS score after EVT (p = .027). After adjusting for confounders (influencing variables), the association between age and post-interventional NIHSS was reduced and non-significant (p = .17). At discharge, a five-year higher age predicted a 0.74 higher mean NIHSS (p = .003). After adjusting for confounders this association was reduced and non-significant (p = .06). Long-term functional outcome: A five-year higher age predicted a 0.20 higher mRS at three months (p < .001). When adjusting for confounders this number was reduced to 0.16, yet still highly significant (p < .001).

CONCLUSIONS

Age seems to have a minor role in predicting neurological improvement after EVT but has an impact on long-term functional outcome. The decision to perform or withhold EVT should therefore not solely be based on age.

Mechanical thrombectomy in stroke patients of working age: Real-world outcomes in Sweden

Introduction

Outcomes after mechanical thrombectomy (MT) in young stroke patients remain elusive due to small patient cohorts. We sought to determine outcomes after MT in stroke patients between ages 18 and 64 years and compare with outcomes in older patients in a large national stroke cohort.

Patients and methods

We used the Swedish National Stroke Registry and the Swedish National Endovascular Thrombectomy Registry to identify all patients treated with MT for anterior circulation occlusions. We examined outcome measures in terms of functional independence at 90 days (modified Rankin Scale score of 0–2), symptomatic intracerebral hemorrhage (sICH), and mortality at 90 days with multivariable logistic regression analysis.

Results

Of 2143 patients, 565 were between 18 and 64 years (26.4%) and 1179 (55.0%) were males. Analysis showed that patient aged 18–64 achieved higher rate of functional independence at 90 days (46.2% vs 28.4%, p < .001), had less often sICH (5.5% vs 6.8%, p = .008), and lower 90-day mortality rate (6.9% vs 17.7%, p < .001). Increasing age was associated with a lesser probability of functional independence at 90 days (adjusted odds ratio (aOR), 0.94; [95% confidence intervals (CIs) 0.93–0.95]), higher odds of mortality at 90 days (aOR, 1.05; [95% CIs 1.03–1.06]), and of sICH (aOR 1.03; [95% CIs 1.01–1.05]).

Conclusion

Patients aged 18–64 years demonstrated better outcome after thrombectomy regarding functional independence, sICH, and mortality at 90 days when compared to older ages.

Acute Recanalization of Large Vessel Occlusion in the Anterior Circulation Stroke: Is Mechanical Thrombectomy Alone Better in Patients over 80 Years of Age? Findings from a Retrospective Observational Study

Real-world data report worse 3-month clinical outcomes in elderly patients with acute ischemic stroke (AIS) treated with mechanical thrombectomy (MT). The aim was to identify factors influencing clinical outcome in elderly patients with anterior circulation AIS treated with MT (±intravenous thrombolysis (IVT)). In a retrospective, monocentric study, analysis of prospectively collected data of 138 patients (≥80 years) was performed. IVT was an independent negative predictor (OR 0.356; 95% CI: 0.134–0.942) and female sex an independent positive predictor (OR 4.179, 95% CI: 1.300–13.438) of 3-month good clinical outcome (modified Rankin scale 0–2). Female sex was also an independent negative predictor of 3-month mortality (OR 0.244, 95% CI: 0.100–0.599). Other independent negative predictors of 3-month good clinical outcome were older age, lower pre-stroke self-sufficiency, more severe neurological deficit and longer procedural intervals. Mortality was also independently predicted by longer procedural interval and by the occurrence of symptomatic intracerebral hemorrhage (p < 0.05 in all cases). Our results demonstrated, that in patients aged ≥80 years with anterior circulation AIS undergoing MT (±IVT), IVT reduced the chance of 3-month good clinical outcome and female sex was associated with a greater likelihood of 3-month good clinical outcome and lower probability of 3-month mortality.

Outcomes in Endovascular Therapy for Basilar Artery Occlusion: Intracranial Atherosclerotic Disease vs. Embolism

Acute ischemic stroke due to basilar artery occlusion (BAO) carries a very poor prognosis. Functional outcomes in BAO patients undergoing endovascular therapy (EVT) may differ according to the specific pathological mechanisms. We aimed to explore the impact of the underlying pathological mechanisms on prognosis at 90-days and long-term follow-up in BAO patients treated with EVT. We analyzed consecutive BAO patients undergoing EVT from December 2012 to December 2018 at a single center (Xuanwu Hospital). Patients were classified into either an intracranial atherosclerotic disease (ICAD) group or an embolic group according to the corresponding angiographic findings. The baseline characteristics and functional outcomes were compared between the two groups. Multivariable logistic regression analysis was performed. Among the 167 patients enrolled, 78 patients (46.7%) were in the ICAD group and 89 patients (53.3%) were assigned to the embolic group. Overall, 149 patients (89.2%) achieved successful reperfusion post-EVT. There were no significant differences in functional outcomes at 90-days and long-term follow-up between the two groups. Similarly, a Kaplan-Meier survival analysis showed similar long-term survival probabilities (P = 0.438). The pathological mechanism was not associated with functional independence (OR, 1.818; 95% CI, 0.694-4.761; P = 0.224), favorable outcome (OR, 1.476; 95% CI, 0.592-3.681; P = 0.403), or mortality (OR, 1.249; 95% CI, 0.483-3.226; P = 0.646). However, based on subgroup analysis, embolic BAO versus ICAD was significantly associated with better functional independence in those aged 60 years and younger (OR, 4.513; 95% CI, 1.138-17.902). In this study, no differences in either 90-days or long-term functional outcomes between ICAD-related BAO and embolic BAO patients undergoing EVT were observed. However, in BAO patients aged ≤ 60 years, the pathological mechanism of embolism was associated with better functional independence.

Age-adjusted infarct volume cut-off points improve stroke outcome prognostication beyond modeling with age and infarct volume

BACKGROUND

Age and infarct volume are among the most powerful predictors of outcome after large vessel occlusion acute strokes (LVOS).

OBJECTIVE

To study the impact of age-adjusted final infarct volume (FIV) on functional outcomes.

METHODS

Review of a prospectively collected thrombectomy database at a tertiary care center between September 2010 and February 2018. Consecutive patients with anterior circulation LVOS who achieved full reperfusion (modified Thrombolysis in Cerebral Infarction 3) were categorized into four age groups: (G1) <60 years, (G2) 60-69, (G3) 70-79, (G4) ≥80 years. The Youden Index was used to identify the optimal FIV cut-off point for good outcome (modified Rankin Scale score 0-2) discrimination in each group and the overall population. The predictive ability of these specific thresholds was evaluated using binary logistic regressions and compared with the non-age-adjusted cut-off point.

RESULTS

516 patients were analyzed (G1: n=171, G2: n=130, G3: n=103, G4: n=112). Patients with poor outcome had a larger FIV in each group (p<0.01 for all). The target FIV cut-off point decreased with increased age: G1: 45.7 mL (sensitivity 56%, specificity 80%); G2: 30.4 mL (sensitivity 63%, specificity 75%); G3: 20.2 mL (sensitivity 76%, specificity 65%); G4: 16.9 mL (sensitivity 68%, specificity 70%). The non-age-adjusted cut-off point was 19.2 mL (sensitivity 70%, specificity 59%).In multivariate analysis, adjusting for confounders including age and FIV, achieving a FIV less than the age-adjusted threshold was an independent predictor of good outcome (aOR=2.72, 95% CI 1.41 to 5.24, p<0.001). In contrast, a similar model including the non-age-adjusted target cut-off point failed to reveal an association with good outcome (aOR=1.72, 95% CI 0.93 to 3.19, p<0.085). Furthermore, the latter model had a weaker outcome predictive ability as assessed by the Akaike information criterion (409 vs 403).

CONCLUSIONS

Age-adjusted infarct volume represents a strong outcome discriminator beyond age and infarct volume in isolation and might help to refine patient selection and improve outcome prognostication in stroke thrombectomy.

Endovascular Thrombectomy after Large-Vessel Ischemic Stroke: Utilization, Outcomes, and Readmissions across the United States

Background Following publication of trials demonstrating the efficacy of thrombectomy, societal guidelines were revised in 2015 to recommend this procedure for large-vessel stroke. Purpose To evaluate real-world thrombectomy rates, adverse events, outcomes, and readmissions across the United States in the 2 years after large-scale adoption of thrombectomy for acute stroke. Materials and Methods In this retrospective study, the authors queried the National Inpatient Sample and Nationwide Readmissions Database for patients undergoing thrombectomy between 2016 and 2017. Thrombectomy rates were compared by using the χ² test. Adjusted risk ratios (aRRs) were obtained for factors affecting routine discharge, mortality, and readmission by using multivariable Poisson regression with clustering at the hospital level. Results There were 290 460 admissions (mean age, 70.5 years ± 14.2 [standard deviation]; 148 620 women) for internal carotid or middle cerebral artery stroke; 30 835 (10.6%) of these patients underwent thrombectomy. Thrombectomy rates were lower in patients aged 90 years or older (1815 of 24 090 patients, 7.5%), Black patients (4280 of 43 365 patients, 9.9%), patients with the lowest income (8520 of 85 905 patients, 9.9%), and those treated in West South Central division hospitals (2695 of 34 355 patients, 7.8%) (P < .001 for all). The inpatient mortality rate was 12.1% (3740 of 30 835 patients), and 19.1% of patients (5900 of 30 835) were discharged to home. In adjusted analyses, routine discharge was less likely in patients aged 90 years or older (aRR: 0.12; 95% CI: 0.09, 0.16; P < .001) and octogenarians (aRR: 0.37; 95% CI: 0.33, 0.41; P < .001). Patients aged 90 years or older (aRR: 1.78; 95% CI: 1.48, 2.14; P < .001), octogenarians (aRR: 1.76; 95% CI: 1.51, 2.06; P < .001), Asians and/or Pacific Islanders (aRR: 1.21; 95% CI: 1.06, 1.39; P = .005), and those treated in teaching (aRR: 1.20; 95% CI: 1.07, 1.34; P = .001) or West South Central division (aRR: 1.35; 95% CI: 1.14, 1.60; P < .001) hospitals had a higher risk of death. Following discharge, 18.9% of patients (3449 of 18 274) were readmitted within 90 days. Conclusion Rates and outcomes of thrombectomy are affected by demographic, socioeconomic, and hospital-related factors. Fewer than one-fifth of patients are discharged to home, nearly one-fifth are readmitted within 90 days, and mortality and outcomes may be less favorable than in published trials. © RSNA, 2021 Online supplemental material is available for this article.

Mechanical Thrombectomy in Nonagenarians: a Systematic Review and Meta-analysis

This systematic review and meta-analysis aimed to summarize the current literature on mechanical thrombectomy (MT) in nonagenarians and to provide updated clinical evidence of its feasibility, effectiveness, and safety in nonagenarians. PubMed, EMBASE, the Cochrane Library, and Web of Science were searched for relevant randomized controlled trials and observational studies that reported the clinical outcomes of nonagenarians with acute ischemic stroke after undergoing mechanical thrombectomy. Risk of bias was assessed using different scales. I² statistic was used to evaluate the heterogeneity of the results, while meta-regression and sensitivity analyses were performed to investigate the source of heterogeneity. Thirteen studies and 657 patients were included. The estimated rate of successful revascularization was 80.82% (95% confidence interval [CI]: 77.48-83.97%), and the rate of favorable outcome (modified Rankin score [mRS] 0-2) was 21.60% (95% CI: 13.81-30.41%). The rate of good outcome (mRS score 0-3) was 23.08% (95% CI: 18.88-27.55%). The estimated risk of death during hospitalization was 20.55% (95% CI: 15.93-25.55%), while the mortality rate at 3 months was 44.38% (95% CI: 33.66-55.36%). The rate of intracranial hemorrhage (ICH) occurrence was 12.84% (95% CI: 5.27-22.68%), while the rate of symptomatic intracranial hemorrhage (sICH) was 3.52% (95% CI: 1.67-5.85%). The rate of hospital-related complications was 26.93% (95% CI: 10.53-47.03%). MT in nonagenarians demonstrated a high rate of successful revascularization. Conversely, the rate of futile revascularization is high with a low functional independence proportion. Therefore, MT should not be indiscriminately advocated in nonagenarians. Satisfactory results require careful selection of patients. Further high-quality studies are needed to clarify the selection algorithm.

Nomogram to Predict Poor Outcome after Mechanical Thrombectomy at Older Age and Histological Analysis of Thrombus Composition

An easy scoring system to predict the risk of poor outcome after mechanical thrombectomy among the elderly is currently not available. Therefore, we aimed to develop a nomogram for predicting the probability of negative prognosis in aged patients with acute ischemic stroke undergoing thrombectomy. In addition, we sought to investigate the association between histological thrombus composition and stroke characteristics. To this end, we prospectively studied a developed cohort using data collected from a stroke center from November 2015 to December 2019. The main outcome was functional independence, defined as a modified Rankin Scale score ≤ 2 at 90 days following a mechanical thrombectomy. A nomogram model based on multivariate logistic models was generated. The retrieved thrombi were stained with hematoxylin and eosin and assessed according to histological composition. Our results demonstrated that age ≥ 72 years was independently associated with poor outcome. A total of 304 participants completed the follow-up data to generate the nomogram model. After multivariate logistic regression, five variables remained independent predictors of outcome, including older age, hemorrhagic transformation, thrombolysis in cerebral infarction score, National Institute of Health Stroke score, and neutrophil-to-lymphocyte ratio, and were used to generate the nomogram. The area under the receiver-operating characteristic curve of the model was 0.803. The clots from elderly subjects with large-artery atherosclerosis, anterior circulation, and successful recanalization groups had a higher percentage of fibrin compared to those of younger patients. This is the first nomogram to be developed and validated in a stroke center cohort for individualized prediction of poor outcome in elderly patients after mechanical thrombectomy. Clot composition provides valuable information on the underlying pathogenesis of oxidation in older patients.

National Trends in Utilization and Outcome of Endovascular Thrombectomy for Acute Ischemic Stroke in Elderly

OBJECTIVE

Octogenarians were excluded and/or underrepresented in the major endovascular thrombectomy (EVT) randomized controlled trials, but continue to make up a growing proportion of stroke patients. To evaluate real-world trends in utilization and outcome of EVT in patients ≥80 years in a large nationally representative database.

METHODS

Using the Nationwide Inpatient Sample (2014-2016), we identified patients admitted to United States hospitals with acute ischemic stroke (AIS) who also underwent EVT. The primary endpoint was good outcome (discharge to home/acute rehabilitation center). Poor outcome (discharge to skilled nursing facility or hospice and in-hospital mortality), intracerebral hemorrhage and in-hospital mortality were secondary outcome measures.

RESULTS

In 376,956 patients with AIS, 6,230(1.54%) underwent EVT. 1,547(24.83%) were ≥80. The rate of EVT in AIS patients ≥80 more than doubled from 0.83%(n = 317) in 2014 to 1.83%(n = 695) in 2016. The rate of good outcome in patients ≥80 was 9%, significantly lower than younger patients (26%, p<0.001). In-hospital mortality was 19% in patients ≥80 compared to 13% in the younger cohort (p < 0.001). There was no difference in the rate of hemorrhagic transformation between octogenarians and younger patients (18.52% vs 17.01%, p=0.19). In patients ≥80 years of age, decreasing baseline comorbidity burden independently predicted good outcome (OR 0.258, 95% CI [0.674- 0.935]).

CONCLUSIONS

A two-fold increase in the utilization of EVT in patients ≥80 years of age was seen from 2014 to 2016. While the comparative rate of good outcome is significantly lower in this age group, elderly patients with fewer comorbidities demonstrated better outcomes after EVT.

Trials in thrombectomy for acute ischemic stroke: Describing the state of clinical research in the field

BACKGROUND

Endovascular thrombectomy has revolutionized treatment of ischemic stroke. Given the clinical and socioeconomic support for thrombectomy, new devices, procedures, and pharmaceuticals have emerged in recent years, and have been subject to a growing number of clinical trials worldwide.

OBJECTIVE

To define the current state of thrombectomy clinical trials, highlight recent trends, and help guide future research in this area.

METHODS

Current and previous clinical trials involving thrombectomy for ischemic stroke were queried from the Clinicaltrials.gov database. Trials were categorized by their current status, study design, funding type, exclusion criteria, study phase, enrollment, start and completion dates, country of origin, item of investigation, outcome metrics, and whether a peer-reviewed publication was linked to the trial.

RESULTS

Querying the ClinicalTrials.gov registry yielded 196 trials, of which 161 (82.1 %) were started within the past 5 years. The average time to completion was 30.6 months. A total of 62 studies (31.6 %) examined the safety or efficacy of a thrombectomy device, 29 (14.8 %) investigated a pharmacological intervention alone or in combination with a device, 59 (30.1 %) examined aspects of the endovascular procedure on patient outcomes, and 14 (7.2 %) examined diagnostic utility during thrombectomy. Most trials were funded by academic centers (53.1 %) or industry (34.7 %). Although the United States contributed the most studies overall (59; 30.1 %), studies from European and Asian countries have been increasing since 2015.

CONCLUSION

These trends indicate an increasing number of trials starting the past few years, with most occurring in Europe and examining devices or aspects of the thrombectomy procedure.

Tracking elemental changes in an ischemic stroke model with X-ray fluorescence imaging

Stroke is a leading cause of long-term disability in adults and a leading cause of death in developed nations. The cascade of cellular events and signalling that occur after cerebral ischemia are complex, however, analyzing global element markers of metabolic state affords the means to monitor stroke severity, status of injury, and recovery. These markers provide a multi-parameter method for assessing changes through the post-stroke time course. We employ synchrotron-based elemental mapping to follow elemental changes in the brain at 1 h, 1-, 2-, and 3-days, and at 1-, 2-, 3-, and 4-weeks post-stroke in a photothrombotic stroke model in mice. Our analysis reveals a highly consistent metabolic penumbra that can be readily identified based on the level of dysregulated potassium and other key elements. Maps of elemental distributions are also useful to demarcate events in the cellular response to the inflammatory cascade, including ion dysregulation, recruitment of cells to the lesion, and glial scar formation.