Methodology of the Interventional Management of Stroke III Trial

Modified Treatment in Brain Ischemia 2b Stopped or Continued After First-Pass Mechanical Thrombectomy for M1 Occlusions

BACKGROUND AND PURPOSE

The superiority of achieving modified Treatment in Cerebral Ischemia (mTICI) from multiple passes versus mTICI 2b from a single pass remains uncertain. We aimed to assess whether additional passes in M1 occlusion patients with a first-pass mTICI 2b score improved clinical and functional outcomes.

METHODS

We analyzed Registry Combined vs. Single Thrombectomy Techniques registry data of consecutive M1-occlusion patients, comparing outcomes of those with mTICI 2b-stopped after the first pass versus continued mechanical thrombectomy (MT) to improve angiographic results (mTICI 2b or mTICI 2c/3). We compared demographic, clinical, angiographic, and clinical outcome data (National Institute of Health Stroke Scale [NIHSS] at 24 h and modified Rankin Scale at 3 months).

RESULTS

Patients with first-pass mTICI 2b had lower NIHSS scores at admission, fewer left-side occlusions, and longer last-seen-well times. Endovascular techniques and time from groin puncture to revascularization were similar across groups. Patients with final mTICI 2c/3 had the highest distal embolism rates in a new territory (0% for mTICI2b-stopped vs. 3% for final mTICI2b-continued; 7.7% for final mTICI2c/3; p = 0.02). The groups had similar rates of death, symptomatic intracranial hemorrhage, same-area distal embolism, other MT-related complications, NIHSS at 24 h, NIHSS change from admission to 24 h, and same-territory distal embolism.

CONCLUSION

Achieving mTICI 2b after the first pass in M1-occlusion patients proved relevant. These patients had comparable clinical and functional outcomes and a lower risk of new territory distal embolisms compared to those with final mTICI 2c/3 scores.

Periodic discharges plus fast activity on electroencephalogram predict worse outcomes in poststroke epilepsy

OBJECTIVE

Postseizure functional decline is a concern in poststroke epilepsy (PSE). However, data on electroencephalogram (EEG) markers associated with functional decline are scarce. Thus, we investigated whether periodic discharges (PDs) and their specific characteristics are associated with functional decline in patients with PSE.

METHODS

In this observational study, patients admitted with seizures of PSE and who had scalp EEGs were included. The association between the presence or absence of PDs and postseizure short-term functional decline lasting 7 days after admission was investigated. In patients with PD, EEG markers were explored for risk stratification of short-term functional decline, according to the American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology. The association between EEG markers and imaging findings and long-term functional decline at discharge and 6 months after discharge, defined as an increase in the modified Rankin Scale score compared with the baseline, was evaluated.

RESULTS

In this study, 307 patients with PSE (median age = 75 years, range = 35-97 years, 64% males; hemorrhagic stroke, 47%) were enrolled. Compared with 247 patients without PDs, 60 patients with PDs were more likely to have short-term functional decline (12 [20%] vs. 8 [3.2%], p < .001), with an adjusted odds ratio (OR) of 4.26 (95% confidence interval [CI] = 1.44-12.6, p = .009). Patients with superimposed fast-activity PDs (PDs+F) had significantly more localized (rather than widespread) lesions (87% vs. 58%, p = .003), prolonged hyperperfusion (100% vs. 62%, p = .023), and a significantly higher risk of short-term functional decline than those with PDs without fast activity (adjusted OR = 22.0, 95% CI = 1.87-259.4, p = .014). Six months after discharge, PDs+F were significantly associated with long-term functional decline (adjusted OR = 4.21, 95% CI = 1.27-13.88, p = .018).

SIGNIFICANCE

In PSE, PDs+F are associated with sustained neuronal excitation and hyperperfusion, which may be a predictor of postseizure short- and long-term functional decline.

Acute ischaemic stroke: recent advances in reperfusion treatment

During the last 5–7 years, tremendous progress was achieved in the reperfusion treatment of acute ischaemic stroke during its first few hours from symptom onset. This review summarizes the latest evidence from randomized clinical trials and prospective registries with a focus on endovascular treatment using stent retrievers, aspiration catheters, thrombolytics, and (in selected patients) carotid stenting. Novel approaches in prehospital (mobile interventional stroke teams) and early hospital (direct transfer to angiography) management are described, and future perspectives (‘all-in-one’ laboratories with angiography and computed tomography integrated) are discussed. There is reasonable chance for patients with moderate-to-severe acute ischaemic stroke to survive without permanent sequelae when the large-vessel occlusion is removed by means of modern pharmaco-mechanic approach. Catheter thrombectomy is now the golden standard of acute stroke treatment. The role of cardiologists in stroke is expanding from diagnostic help (to reveal the cause of stroke) to acute therapy in those regions where such up-to-date Class I. A treatment is not yet available.

The Jrecan Device: Preclinical Data of a Novel Thrombectomy Device in Acute Thromboembolism Model of Beagle Dogs

Objective

The aim of this study is to investigate the safety and efficiency of a Jrecan^® flow restoration system, a novel thrombectomy device, in an arterial thromboembolic occlusion model of Beagle dogs.

Methods

A total of 12 Beagle dogs with acute thromboembolism were randomized to receive mechanical thrombectomy with either Jrecan^® flow restoration device or Trevo^TM PROVUE Device (2:1). The efficacy and safety of the two devices, including recanalization rate, the presence of distal embolism, vasospasm, vessel perforation, and vessel injuries were evaluated through DSA and microscopic examination.

Result

A 100% recanalization rate (mTICI 2b/3) was achieved in both groups. Endothelial and subendothelial injuries occurred in all target vessels. Focal disruption of internal elastic lamina was observed in 4 cases. The mean vessel injury score of the Jrecan^® group was 1.16 ± 0.48, significantly lower than that of the Trevo^TM group (1.54 ± 0.8) (P < 0.001).

Conclusion

The Jrecan^® and Trevo^TM devices demonstrated an equally high recanalization rate in Beagle dogs with acute thromboembolism. However, histological findings revealed that the Jrecan^® stent seemed to be safer than the Trevo^TM device during clot retrieval, which might be related to a more appropriate radial force provided by the Jrecan^® stent that resulted from its wider cell design.

Effectiveness of Thrombectomy in Stroke According to Baseline Prognostic Factors: Inverse Probability of Treatment Weighting Analysis of a Population-Based Registry

Background and Purpose

 In real-world practice, the benefit of mechanical thrombectomy (MT) is uncertain in stroke patients with very favorable or poor prognostic profiles at baseline. We studied the effectiveness of MT versus medical treatment stratifying by different baseline prognostic factors.

Methods

 Retrospective analysis of 2,588 patients with an ischemic stroke due to large vessel occlusion nested in the population-based registry of stroke code activations in Catalonia from January 2017 to June 2019. The effect of MT on good functional outcome (modified Rankin Score ≤2) and survival at 3 months was studied using inverse probability of treatment weighting (IPTW) analysis in three pre-defined baseline prognostic groups: poor (if pre-stroke disability, age >85 years, National Institutes of Health Stroke Scale [NIHSS] >25, time from onset >6 hours, Alberta Stroke Program Early CT Score <6, proximal vertebrobasilar occlusion, supratherapeutic international normalized ratio >3), good (if NIHSS <6 or distal occlusion, in the absence of poor prognostic factors), or reference (not meeting other groups’ criteria).

Results

 Patients receiving MT (n=1,996, 77%) were younger, had less pre-stroke disability, and received systemic thrombolysis less frequently. These differences were balanced after the IPTW stratified by prognosis. MT was associated with good functional outcome in the reference (odds ratio [OR], 2.9; 95% confidence interval [CI], 2.0 to 4.4), and especially in the poor baseline prognostic stratum (OR, 3.9; 95% CI, 2.6 to 5.9), but not in the good prognostic stratum. MT was associated with survival only in the poor prognostic stratum (OR, 2.6; 95% CI, 2.0 to 3.3).

Conclusions

 Despite their worse overall outcomes, the impact of thrombectomy over medical management was more substantial in patients with poorer baseline prognostic factors than patients with good prognostic factors.

The outcomes of mechanical thrombectomy in nonagenarians and octogenarians in a majority hispanic population

BACKGROUND/OBJECTIVE

Elderly patients (≥ 80 years) were underrepresented in randomized trials that proved the efficacy and safety of mechanical thrombectomy (MT) in acute ischemic strokes (AIS) due to large vessel occlusion (LVO). Additionally, the impact of race and socioeconomics on AIS outcomes is well-reported. We sought to compare the MT clinical outcomes between octogenarians and nonagenarians, the majority of whom are Hispanic, in underserved border communities.

METHODS

This is a retrospective cohort study that was conducted in a comprehensive stroke center between 2012 and 2020. The baseline characteristics and outcomes were compared between the two groups. The primary measured outcome included a favorable outcome on the modified Rankin Scale (mRS) after three months (mRS ≤ 2). Secondary outcomes included mortality, symptomatic intracerebral hemorrhage (sICH), and an improvement in NIH Stroke Scale (NIHSS) score (≤4).

RESULTS

Of 215 included patients, 184 (85.6%) were octogenarians and 31 (14.4%) were nonagenarians. There were no significant differences between octogenarians and nonagenarians in terms of rates of favorable outcomes after three months (30.4% vs. 19.4%, p = 0.247), clinical improvement in discharge NIHSS (16.3% vs. 19.4%, p = 0.753), mortality (24.5% vs. 29.0%; p = 0.710) and sICH (6.5% vs. 3.2%, p = 0.780). Furthermore, Hispanic and non-Hispanic patients had similar outcomes.

CONCLUSION

There were no significant differences in the outcomes of MT between octogenarians and nonagenarians and between Hispanic and non-Hispanic patients. The similar clinical outcomes between both age groups in our study and the lower rates of sICH support the use of this treatment among people who are aged 80 or older.

Circulating Cytokines and Growth Factors in Acute Cerebral Large Vessel Occlusion-Association with Success of Endovascular Treatment

Mechanical thrombectomy (MT) is a highly efficient treatment in patients with acute ischemic stroke due to large vessel occlusion (LVO). However, in a relevant proportion of LVO, no sufficient recanalization can be achieved. The composition of cerebral thrombi is highly heterogeneous and may constitute a relevant factor for insufficient reperfusion. We hypothesized that circulating cytokines and growth factors involved in thromboinflammation and platelet activation may be associated with reperfusion status and thrombus composition in patients undergoing MT. An according biomarker panel was measured in plasma specimens taken prior to MT and at a 7-day follow-up. The reperfusion status was categorized into sufficient or insufficient. The composition of retrieved thrombi was histologically analyzed. Differences of baseline biomarker concentrations between insufficient and sufficient reperfusions were highest for interferon (IFN)-γ, epidermal growth factor, platelet-derived growth factor (PDGF)-AB/BB, and IFN-γ-induced protein 10 (IP-10/CXCL10). After applying correction for multiple comparisons and logistic regression analysis adjusting for stroke etiology, intravenous thrombolysis, and vascular risk factors, PDGF-AB/BB was identified as an independent predictor of reperfusion status (odds ratio: 0.403; 95% confidence interval: 0.199-0.819). Histological analysis revealed that the majority of thrombi had a mixed composition. In conclusion, this study provides the first evidence that cytokines and growth factors are potential effectors in patients undergoing MT for the treatment of acute ischemic stroke.

Acute Kidney Injury in Acute Ischemic Stroke Patients in Clinical Trials

OBJECTIVES

Acute ischemic stroke patients are at risk of acute kidney injury due to volume depletion, contrast exposure, and preexisting comorbid diseases. We determined the occurrence rate and identified predictors associated with acute kidney injury in acute ischemic stroke patients.

SETTING

Multiple specialized ICUs within academic medical centers.

DESIGN

Post hoc analysis of pooled data from prospective randomized clinical trials.

PATIENTS

Acute ischemic stroke patients recruited within 3 hours or within 5 hours of symptom onset.

INTERVENTIONS

IV recombinant tissue plasminogen activator, endovascular treatment, IV albumin, or placebo.

MEASUREMENTS AND MAIN RESULTS

Serum creatinine levels from baseline and within day 5 or discharge were used to classify acute kidney injury classification into stages. Any increase in serum creatinine was seen in 697 (36.1%) and acute kidney injury was seen in 68 (3.5%) of 1,931 patients with acute ischemic stroke. Severity of acute kidney injury was grade I, II, and III in 3.1%, 0.4%, and 0.05% patients, respectively. Patients with albumin (5.5% compared with 2.6%; p = 0.001), preexisting hypertension (4.3% compared with 1.5%; p = 0.0041), and preexisting renal disease (9.1% compared with 3.0%; p < 0.0001) had higher risk of acute kidney injury. The risk of acute kidney injury was lower between those who either underwent CT angiography (2.0% compared with 4.7%; p = 0.0017) or endovascular treatment (1.6% compared with 4.2%; p = 0.0071). In the multivariate analysis, hypertension (odds ratio, 2.6; 95% CI, 1.2-5.6) and renal disease (odds ratio, 3.5; 95% CI, 1.9-6.5) were associated with acute kidney injury. The risk of death was significantly higher among patients with acute kidney injury (odds ratio, 2.7; 95% CI, 1.4-4.9) after adjusting for age and National Institutes of Health Stroke Scale score strata.

CONCLUSIONS

The occurrence rate of acute kidney injury in acute ischemic stroke patients was low and was not higher in patients who underwent CT angiogram or those who received endovascular treatment. Occurrence of acute kidney injury increased the risk of death within 3 months among acute ischemic stroke patients.

Critical appraisal of Bayesian dynamic borrowing from an imperfectly commensurate historical control

Bayesian dynamic borrowing designs facilitate borrowing information from historical studies. Historical data, when perfectly commensurate with current data, have been shown to reduce the trial duration and the sample size, while inflation in the type I error and reduction in the power have been reported, when imperfectly commensurate. These results, however, were obtained without considering that Bayesian designs are calibrated to meet regulatory requirements in practice and even no-borrowing designs may use information from historical data in the calibration. The implicit borrowing of historical data suggests that imperfectly commensurate historical data may similarly impact no-borrowing designs negatively. We will provide a fair appraiser of Bayesian dynamic borrowing and no-borrowing designs. We used a published selective adaptive randomization design and real clinical trial setting and conducted simulation studies under varying degrees of imperfectly commensurate historical control scenarios. The type I error was inflated under the null scenario of no intervention effect, while larger inflation was noted with borrowing. The larger inflation in type I error under the null setting can be offset by the greater probability to stop early correctly under the alternative. Response rates were estimated more precisely and the average sample size was smaller with borrowing. The expected increase in bias with borrowing was noted, but was negligible. Using Bayesian dynamic borrowing designs may improve trial efficiency by stopping trials early correctly and reducing trial length at the small cost of inflated type I error.

Prospective Endovascular Treatment in Acute Ischemic Stroke Evaluating Non-Contrast Head CT versus CT Perfusion (PLEASE No CTP)

Background

Studies have shown a lack of agreement of computed tomography perfusion (CTP) in the selection of acute ischemic stroke (AIS) patients for endovascular treatment.

Purpose

To demonstrate whether non-contrast computed tomography (CT) within 8 h of symptom onset is comparable to CTP imaging.

Methods

Prospective study of consecutive anterior circulation AIS patients with a National Institute of Health Stroke Scale (NIHSS) score > 7 presenting within 8 h of symptom onset with endovascular treatment. All patients had non-contrast CT, CT angiography, and CTP. The neuro-interventionalist was blinded to the results of the CTP and based the treatment decision using the Alberta Stroke Program Early CT score (ASPECTS). Baseline demographics, co-morbidities, and baseline NIHSS scores were collected. Outcomes were modified Rankin scale (mRS) score at discharge and in-hospital mortality. Good outcomes were defined as a mRS score of 0-2.

Results

283 AIS patients were screened for the trial, and 119 were enrolled. The remaining patients were excluded for: posterior circulation stroke, no CTP performed, could not obtain consent, and NIHSS score < 7. Mean -NIHSS score at admission was 16.8 ± 3, and mean ASPECTS was 8.4 ± 1.4. There was no statistically significant correlation with CTP penumbra and good outcomes: 50 versus 47.8% with no penumbra present (p = 0.85). In patients without evidence of CTP penumbra, there was 22.5% mortality compared to 22.1% mortality in patients with a CTP penumbra. If ASPECTS ≥7, 64.6% had good outcome versus 13.3% if ASPECTS < 7 (p < 0.001). Patients with an ASPECTS ≥7 had 10% mortality versus 51.4% in patients with an ASPECTS < 7 (p < 0.001).

Conclusions

CTP penumbra did not identify patients who would benefit from endovascular treatment when patients were selected with non-contrast CT ASPECTS ≥7. There is no correlation of CTP penumbra with good outcomes or mortality. Larger prospective trials are warranted to justify the use of CTP within 6 h of symptom onset.

Bayesian selective response-adaptive design using the historical control

High quality historical control data, if incorporated, may reduce sample size, trial cost, and duration. A too optimistic use of the data, however, may result in bias under prior-data conflict. Motivated by well-publicized two-arm comparative trials in stroke, we propose a Bayesian design that both adaptively incorporates historical control data and selectively adapt the treatment allocation ratios within an ongoing trial responsively to the relative treatment effects. The proposed design differs from existing designs that borrow from historical controls. As opposed to reducing the number of subjects assigned to the control arm blindly, this design does so adaptively to the relative treatment effects only if evaluation of cumulated current trial data combined with the historical control suggests the superiority of the intervention arm. We used the effective historical sample size approach to quantify borrowed information on the control arm and modified the treatment allocation rules of the doubly adaptive biased coin design to incorporate the quantity. The modified allocation rules were then implemented under the Bayesian framework with commensurate priors addressing prior-data conflict. Trials were also more frequently concluded earlier in line with the underlying truth, reducing trial cost, and duration and yielded parameter estimates with smaller standard errors.

Impact of Treatment Time on the Long-Term Outcome of Stroke Patients Treated With Mechanical Thrombectomy

OBJECTIVE

To assess the long-term functional outcome of stroke in patients treated with mechanical thrombectomy (MT) performed during work hours (on-hours) versus after-hours, weekends, and official holidays (off-hours).

METHODS

Data on all patients receiving MT at a comprehensive stroke center was collected between December 2014-December 2016. Our primary outcomes were the discharge and 90-day modified Rankin Scale (mRS). We developed propensity scores for off-hours treatment and used inverse probability of treatment weights to address confounding. We estimated logistic regression to assess the relationship between off-hours treatment and favorable patient outcomes. Independent variables include receiving thrombectomy during the off-hours, admission National Institute of Health Stroke Scale (NIHSS), door to groin time in minutes, age, and race.

RESULTS

During the study period, 80 (41%) patients underwent thrombectomy during on-hours and 116 (59%) during off-hours. Mean age was 69.1 years for the on-hours group and 64.1 years for the off-hours group (P = .02). There were no statistically significant differences in median admission NIHSS, rate of alteplase administration, mean time from last known well to thrombectomy, rate of revascularization, and rate of hemorrhagic transformation between the 2 groups. Logistic regression analysis showed the probability of a favorable outcome at discharge (mRS ≤ 2) is 12.6 % lower for off-hours patients (P = .038, [95%CI -.25 to -.01]). For patients with a 90-day mRS (n = 117), the probability of a favorable outcome was 18.7% lower for those treated during the off-hours (P = .029, [95%CI -.36 to -.02]).

CONCLUSIONS

There is a higher probability of a good functional outcome in acute ischemic stroke patients who receive MT when performed during regular work hours.

Determining the joint effect of obesity and diabetes on functional disability at 3-months and on all-cause mortality at 1-year following an ischemic stroke

BACKGROUND

Obesity and diabetes mellitus, or diabetes, are independently associated with post-ischemic stroke outcomes (e.g., functional disability and all-cause mortality). Although obesity and diabetes are also associated with post-ischemic stroke outcomes, the joint effect of obesity and diabetes on these post-ischemic stroke outcomes has not been explored previously. The purpose of the current study was to explore whether the effect of obesity on post-ischemic stroke outcomes differed by diabetes status in a cohort of acute ischemic stroke subjects with at least a moderate stroke severity.

METHODS

Data from the Interventional Management of Stroke (IMS) III clinical trial was analyzed for this post-hoc analysis. A total of 656 subjects were enrolled in IMS III and were followed for one year. The joint effects of obesity and diabetes on functional disability at 3-months and all-cause mortality at 1-year were examined.

RESULTS

Of 645 subjects with complete obesity and diabetes information, few were obese (25.74%) or had diabetes (22.64%). Obese subjects with diabetes and non-obese subjects without diabetes had similar odds of functional disability at 3-months following an ischemic stroke (adjusted common odds ratio, 1.038, 95% CI: 0.631, 1.706). For all-cause mortality at 1-year following an ischemic stroke, obese subjects with diabetes had a similar hazard compared with non-obese subjects without diabetes (adjusted hazard ratio, 1.005, 95% CI: 0.559, 1.808). There was insufficient evidence to declare a joint effect between obesity and diabetes on either the multiplicative scale or the additive scale for both outcomes.

CONCLUSIONS

In this post-hoc analysis of data from the IMS III clinical trial of acute ischemic stroke patients with at least a moderate stroke severity, there was not sufficient evidence to determine that the effect of obesity differed by diabetes status on post-ischemic stroke outcomes. Additionally, there was not sufficient evidence to determine that either factor was independently associated with all-cause mortality. Future studies could differentiate between metabolically healthy and metabolically unhealthy patients within BMI categories to determine if the effect of obesity on post-stroke outcomes differs by diabetes status.

Neuroprotectants in the Era of Reperfusion Therapy

For decades, numerous pharmacological and non-pharmacological strategies have been evaluated without success to limit the consequences of the ischemic cascade, but more rarely the therapies were explored as add on remedies on individuals also receiving reperfusion therapies. It is plausible that these putative neuroprotectants never reached the ischemic brain in adequate concentrations. Currently, the concept of neuroprotection incorporates cerebral perfusion as an obligatory substrate upon which ischemic brain survival depends, and it is plausible that some of the compounds tested in previous neuroprotection trials might have resulted in more favorable results if reperfusion therapies had been co-administered. Nonetheless, pharmacological or mechanical thrombectomy are frequently powerless to fully reperfuse the ischemic brain despite achieving a high rate of recanalization. This review covers in some detail the importance of the microcirculation, and the barriers that may hamper flow reperfusion at the microcirculatory level. It describes the main mechanisms leading to microcirculatory thrombosis including oxidative/nitrosative stress and refers to recent efforts to ameliorate brain perfusion in combination with the co-administration of neuroprotectants mainly aimed at harnessing oxidative/nitrosative brain damage.

Modified Thrombolysis in Cerebral Infarction 2C/Thrombolysis in Cerebral Infarction 3 Reperfusion Should Be the Aim of Mechanical Thrombectomy

Background and Purpose—

Although successful reperfusion is usually defined as a modified Thrombolysis in Cerebral Infarction (mTICI) 2B or 3 at the end of the procedure, studies have shown that mTICI 2B patients had poorer functional outcomes than TICI 3 patients. An mTICI 2C category has been recently introduced for patients with near-complete perfusion except for slow flow in a few distal cortical vessels or presence of small distal cortical emboli after mechanical thrombectomy. The purpose of this study was to evaluate the difference in functional outcome between patients achieving successful reperfusion (ie, mTICI 2B, mTICI 2C, and TICI 3 scores).

Methods—

Ancillary study from the ASTER (Contact Aspiration Versus Stent Retriever for Successful Revascularization) prospective multicenter blinded end point trial. Reperfusion results are reported as the mTICI score, including the mTICI 2C grade. Primary outcome was the percentage of patients with favorable outcome defined as a 90-day modified Rankin Scale score of 0 to 2.

Results—

Two hundred ninety patients with successful reperfusion (mTICI ≥2B), harboring ischemic stroke secondary to occlusion of the anterior circulation within 6 hours of onset of symptoms, undergoing mechanical thrombectomy by contact aspiration or stent retriever were included. Favorable outcome (pre-specified as primary outcome of this ancillary study) did not differ significantly between the 3 reperfusion grades, with a similar positive effect of 2C (odds ratio, 1.71; 95% confidence interval, 0.98–3.00) and 3 (odds ratio, 1.73; 95% confidence interval, 0.88–3.41) grades compared with 2B grade. After combining grades 2C and 3, patients had a significantly higher rate of favorable outcome than patients with 2B (odds ratio, 1.72; 95% confidence interval, 1.01–2.90; P =0.043). Favorable outcome rate decreased with increasing onset-to-reperfusion time, with no significant interaction between mTICI 2C/3 grade and onset-to-reperfusion time on favorable outcome.

Conclusions—

Combining mTICI 2C and TICI 3 grades helps to determine a subgroup of patients achieving better functional outcomes than mTICI 2B patients. Achieving mTICI 2C/3 reperfusion should be the new aim of mechanical thrombectomy for anterior circulation LVO.

Rates and predictors of futile recanalization in patients undergoing endovascular treatment in a multicenter clinical trial

PURPOSE

The phenomenon of futile recanalization, defined as lack of clinical benefit despite angiographic recanalization, is an important limitation of endovascular treatment for acute ischemic stroke. We aim to characterize the occurrence and predictors of futile recanalization in the endovascular arm of the Interventional Management of Stroke (IMS) III trial.

METHODS

Patients with near complete or complete recanalization (TICI grades 2b and 3) were divided according to functional outcome at 3 months into "meaningful recanalization," defined as mRS score 0-2, and "futile recanalization," mRS score 3-6. Multivariate analysis was performed to identify predictors of futile recanalization.

RESULTS

Futile recanalization was observed in 61 (47%) of 130. Compared to meaningful recanalization group, the futile recanalization group had higher proportion of women (62.3 vs. 43.5%; p = 0.032), higher incidence of diabetes mellitus (29.5 vs. 8.7%; p = 0.004) and coronary artery disease (27.9 vs. 13%; p = 0.05), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (median [range] 19 [11-31] vs. 15 [8-26], p < 0.001), higher baseline serum glucose (7.6 ± 2.6 vs. 6.7 ± 1.7 mmol/L; p = 0.039), and longer onset-to-start of endovascular treatment time (265.8 ± 48.3 vs. 239.2 ± 47.7 min; p = 0.007). In multivariate analysis, NIHSS (OR 1.3; 95% CI 1.1-1.4), female gender (OR 3.0; 95% CI 1.1-8.2), and onset-to-start of endovascular treatment time (OR 1.2; 95% CI 1.1-1.3) were independent predictors of futile recanalization.

CONCLUSION

In IMS III, futile recanalization was common. Delay in endovascular treatment is the only modifiable risk factor. Additional strategies for non-modifiable risk factors-female gender and high NIHSS-need to be identified.

Comparison of Endovascular Treatment with Intravenous Thrombolysis for Isolated M2 Segment of Middle Cerebral Artery Occlusion in Acute Ischemic Stroke

BACKGROUND

The benefit of endovascular treatment for distal large artery ischemic occlusions such as M2 segment of middle cerebral artery is not clear.

METHODS

We retrospectively analyzed data from 51 subjects who had an isolated M2 segment occlusion on baseline computed tomographic (CT) angiogram who were randomized to either intravenous (IV) recombinant tissue plasminogen activator (rt-PA) followed by endovascular treatment or IV rt-PA alone in a multicenter trial. We determined the effect of endovascular treatment on occurrence of excellent [mRS (modified Rankin scale) scores of 0-1] functional outcomes at three months and any death within 3 and 12 months. We also performed proportional odds logistic regression analysis to compare the distribution of mRS scores between the two groups. Each of the analyses was adjusted for age, baseline Alberta stroke program early CT score strata, and baseline National Institutes of Health Stroke scale score strata.

RESULTS

At three months, the rate of excellent functional outcome (38.2% versus 17.6%, unadjusted odds ratio 2.9; 95% confidence interval ; 0.7-12.1; p = 0.15) was non-significantly higher among subjects with M2 segment occlusion who were randomized to endovascular treatment. In multivariate analysis, the odds of excellent functional outcome at three months were non-significantly higher among subjects who were randomized to endovascular treatment at three months (OR 2.7; 95% CI; 0.6-13.6; p = 0.22). There was a trend toward lower disability grades in subject randomized to endovascular treatment when distribution of the mRS score at three months were compared (common OR 2.6; p = 0.084), adjusting for potential confounders. The rates of any death within 3 (adjusted OR 0.1; 95% CI; 0.1-0.8; p = 0.031) and within 12 months (adjusted OR 0.1; 95% CI; 0.1-0.7; p = 0.022) were significantly lower among those who were randomized to endovascular treatment.

CONCLUSION

In this post-hoc analysis, acute ischemic stroke subjects who had isolated M2 segment occlusion randomized to endovascular treatment appeared to have lower mortality and a trend toward lower grades of disability.

Complete reperfusion is required for maximal benefits of mechanical thrombectomy in stroke patients

A mTICI 2b or a mTICI 3 score are currently considered success following mechanical thrombectomy (MT) in acute stroke but is undetermined whether the two scores translate equivalent outcomes. We present a single-center, retrospective cohort of patients with anterior circulation stroke treated with MT and achieving a final mTICI score 2b or 3. A multimodal CT at baseline and a multimodal MRI at 24 hours assessed the growth of the infarct, and the modified Rankin Scale (mRS) assessed functional outcome at 90 days. The primary outcome was the shift analysis of the mRS at day 90 in ordinal regression adjusted for covariates (age, sex, pretreatment NIHSS score, target occlusion, infarct core, pretreatment alteplase), and the collateral score. Infarct growth was explored in a similarly adjusted multiple linear regression model. MT was started within a median of 285 minutes of symptom onset; 51 (41%) patients achieved a mTICI 2b, and 74 (59%), a mTICI 3. mTICI 3 resulted in better mRS score transitions than mTICI 2b (odds ratio 2.018 [95% CI 1.033–3.945], p = 0. 040), and reduced infarct growth (p = 0.002). We conclude that in patients with acute stroke receiving MT, success should be redefined as achieving a mTICI 3 score.

Endovascular Therapy Demonstrates Benefit over Intravenous Recombinant Tissue Plasminogen Activator Based on Repeatedly Measured National Institutes of Health Stroke Scale

BACKGROUND AND PURPOSE

The Interventional Management of Stroke (IMS) III trial was a randomized controlled trial designed to compare the effect of endovascular therapy after intravenous recombinant tissue plasminogen activator (i.v. rt-PA) as compared to i.v. rt-PA alone. The primary outcome was modified Rankin Scale at 90 days. Secondary outcomes included National Institutes of Health Stroke Scale (NIHSS), which was assessed repeatedly through 90 days. The objective of this analysis is to evaluate the treatment effect of endovascular therapy over time on NIHSS.

METHODS

656 subjects were enrolled in the IMS III trial, including 434 subjects randomized to endovascular therapy and 222 to i.v. rt-PA only. NIHSS scores evaluated at 40 min, 24 h, Day 5, and Day 90 were included in the analysis. A covariance structure model was used to investigate the treatment effect on NIHSS over time, adjusting for relevant covariates including baseline stroke severity. Model assumptions were valid.

RESULTS

Based on the covariance structure model, after adjusting for relevant baseline covariates, a significant time-by-treatment interaction effect (p = 0.0137) was observed. Only NIHSS at Day 90 showed a significant treatment effect (p = 0.0473), with subjects in the endovascular arm having a lower NIHSS (less neurologic deficit) compared to the i.v. rt-PA arm.

CONCLUSIONS

The IMS III trial demonstrated an endovascular treatment effect based on the secondary outcome of NIHSS. However, the magnitude of this treatment effect varied by the time of assessment. It was only at Day 90 that the endovascular arm had a significantly lower NIHSS compared to that in the i.v. rt-PA arm.

Selection of patients for intra-arterial treatment for acute ischaemic stroke: development and validation of a clinical decision tool in two randomised trials

Objective To improve the selection of patients with acute ischaemic stroke for intra-arterial treatment using a clinical decision tool to predict individual treatment benefit.Design Multivariable regression modelling with data from two randomised controlled clinical trials.Setting 16 hospitals in the Netherlands (derivation cohort) and 58 hospitals in the United States, Canada, Australia, and Europe (validation cohort).Participants 500 patients from the Multicenter Randomised Clinical Trial of Endovascular Treatment for Acute Ischaemic Stroke in the Netherlands trial (derivation cohort) and 260 patients with intracranial occlusion from the Interventional Management of Stroke III trial (validation cohort).Main outcome measures The primary outcome was the modified Rankin Scale (mRS) score at 90 days after stroke. We constructed an ordinal logistic regression model to predict outcome and treatment benefit, defined as the difference between the predicted probability of good functional outcome (mRS score 0-2) with and without intra-arterial treatment.Results 11 baseline clinical and radiological characteristics were included in the model. The externally validated C statistic was 0.69 (95% confidence interval 0.64 to 0.73) for the ordinal model and 0.73 (0.67 to 0.79) for the prediction of good functional outcome, indicating moderate discriminative ability. The mean predicted treatment benefit varied between patients in the combined derivation and validation cohort from -2.3% to 24.3%. There was benefit of intra-arterial treatment predicted for some individual patients from groups in which no treatment effect was found in previous subgroup analyses, such as those with no or poor collaterals.Conclusion The proposed clinical decision tool combines multiple baseline clinical and radiological characteristics and shows large variations in treatment benefit between patients. The tool is clinically useful as it aids in distinguishing between individual patients who may experience benefit from intra-arterial treatment for acute ischaemic stroke and those who will not.Trial registration clinicaltrials.gov NCT00359424 (IMS III) and isrctn.com ISRCTN10888758 (MR CLEAN).

Treatment of stroke with early imaging and revascularization: when to be aggressive?

Neuroimaging has a key role in the assessment and treatment of acute stroke. Cerebral computer tomography is the first step to differentiate hemorragic from ischemic stroke and to detect, in the latter, early signs representative of the lesion severity and predicting a possible hemorrhagic infarction after thrombolytic treatment.Advanced neuroimaging techniques are relevant in the assessment of the ischemic and/or hypo-perfused area, being an essential tool in uncertain situations or when the time of symptoms onset is unavailable, increasing the efficacy and safety of endovenous thrombolysis by enlarging its therapeutic window and leading to more accurate selection of patients to be treated.Moreover, advanced neuroimaging may be of help in choosing the patients to be submitted to endovascular treatment when occlusion of an intracranial artery is documented, either after intravenous thrombolysis or as a primary approach.Here we describe the impact of neuroimaging in the decisional process in acute ischemic stroke, presenting the literature evidence on the topic, especially regarding the recent trials on endovascular treatment.

Severe carotid stenosis and delay of reperfusion in endovascular stroke treatment: an Interventional Management of Stroke-III study

OBJECTIVE The impact of extracranial carotid stenosis on interventional revascularization of acute anterior circulation stroke is unknown. The authors examined the effects of high-grade carotid stenosis on the results of endovascular treatment of patients in the Interventional Management of Stroke (IMS)-III trial. METHODS The 278 patients in the endovascular arm of the IMS-III trial were categorized according to the degree of carotid stenosis as determined by angiography. In comparing patients with severe stenosis or occlusion (≥ 70%) to those without severe stenosis (< 70%), the authors evaluated the time to endovascular reperfusion, modified Thrombolysis in Cerebrovascular Infarction (mTICI) scores, 24-hour mean infarct volumes, symptomatic intracerebral hemorrhage rates, and modified Rankin Scale (mRS) scores at 90 days. RESULTS Compared with the 249 patients with less than 70% stenosis, patients with severe stenosis (n = 29) were found to have a significantly longer mean time to reperfusion (105.7 vs 77.7 minutes, p = 0.004); differences in mTICI scores, infarct volumes, hemorrhage rates, and mRS scores at 90 days did not reach statistical significance. Multiple regression analysis revealed that severe carotid stenosis (p < 0.0001) and higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (p = 0.004) were associated with an increase in time to reperfusion. Older age (p < 0.0001), higher NIHSS score (p < 0.0001), and the absence of reperfusion (p = 0.001) were associated with worse clinical outcomes. CONCLUSIONS Severe ipsilateral ICA stenosis was associated with a significantly longer time to reperfusion in the IMS-III trial. Although these findings may not translate directly to modern devices, this 28-minute delay in reperfusion has significant implications, raising concern over the treatment of tandem ICA stenosis and downstream large-vessel occlusion.

Impact of Modified TICI 3 versus Modified TICI 2b Reperfusion Score to Predict Good Outcome following Endovascular Therapy

BACKGROUND AND PURPOSE

The TICI score is widely used to evaluate cerebral perfusion before and after the endovascular treatment of stroke. Recent studies showing the effectiveness and safety of mechanical thrombectomy combine modified TICI 2b and modified TICI 3 to assess the technical success of endovascular treatment. The purpose of this study was to determine how much clinical outcomes differ between patients achieving modified TICI 2b and modified TICI 3 reperfusion.

MATERIALS AND METHODS

We analyzed 222 consecutive patients with acute large intracranial artery occlusion of the anterior circulation having achieved modified TICI 2b or modified TICI 3 reperfusion after thrombectomy. The primary end point was the rate of favorable outcome defined as the achievement of a modified Rankin Scale score of 0-2 at 3 months.

RESULTS

Patients with modified TICI 3 more often had favorable collateral circulation and atherosclerosis etiology, with a shorter time from onset to reperfusion than patients with modified TICI 2b (all P < .05). The number of total passes to achieve reperfusion was higher in the modified TICI 2b group (median, 2; interquartile range, 1-3, 1-9) versus (median, 1; interquartile range, 1-2, 1-8) in the modified TICI 3 group (P = .0002). Favorable outcome was reached more often for patients with modified TICI 3 than for those with modified TICI 2b (71.7% versus 50.5%, P = .001), with a similar difference when considering excellent outcome. In addition, patients with modified TICI 3 had a lower intracerebral hemorrhage rate (23.0% versus 45.0%, P < .001).

CONCLUSIONS

Patients with modified TICI 3 reperfusion have better functional outcomes than those with modified TICI 2b. Given the improving reperfusion rates obtained with thrombectomy devices, future thrombectomy trials should consider modified TICI 2b and modified TICI 3 status separately.

Endovascular Therapy of M2 Occlusion in IMS III: Role of M2 Segment Definition and Location on Clinical and Revascularization Outcomes

BACKGROUND AND PURPOSE

Uncertainty persists regarding the safety and efficacy of endovascular therapy of M2 occlusions following IV tPA. We reviewed the impact of revascularization on clinical outcomes in 83 patients with M2 occlusions in the Interventional Management of Stroke III trial according to specific M1-M2 segment anatomic features.

MATERIALS AND METHODS

Perfusion of any M2 branch distinguished M2-versus-M1 occlusion. Prespecified modified TICI and arterial occlusive lesion revascularization and clinical mRS 0-2 end points at 90 days for endovascular therapy-treated M2 occlusions were analyzed. Post hoc analyses of the relationship of outcomes to multiple baseline angiographic M2 and M1 subgroup characteristics were performed.

RESULTS

Of 83 participants with M2 occlusion who underwent endovascular therapy, 41.0% achieved mRS 0-2 at 90 days, including 46.6% with modified TICI 2-3 reperfusion compared with 26.1% with modified TICI 0-1 reperfusion (risk difference, 20.6%; 95% CI, -1.4%-42.5%). mRS 0-2 outcome was associated with reperfusion for M2 trunk (n = 9) or M2 division (n = 42) occlusions, but not for M2 branch occlusions (n = 28). Of participants with trunk and division occlusions, 63.2% with modified TICI 2a and 42.9% with modified TICI 2b reperfusion achieved mRS 0-2 outcomes; mRS 0-2 outcomes for M2 trunk occlusions (33%) did not differ from distal (38.2%) and proximal (26.9%) M1 occlusions.

CONCLUSIONS

mRS 0-2 at 90 days was dependent on reperfusion for M2 trunk but not for M2 branch occlusions. For M2 division occlusions, good outcome with modified TICI 2b reperfusion did not differ from that in modified TICI 2a. M2 segment definition and occlusion location may contribute to differences in revascularization and good outcome between Interventional Management of Stroke III and other endovascular therapy studies.

Expanding the concept of neuroprotection for acute ischemic stroke: The pivotal roles of reperfusion and the collateral circulation

This review surveys the efforts taken to achieve clinically efficacious protection of the ischemic brain and underscores the necessity of expanding our purview to include the essential role of cerebral perfusion and the collateral circulation. We consider the development of quantitative strategies to measure cerebral perfusion at the regional and local levels and the application of these methods to elucidate flow-related thresholds of ischemic viability and to characterize the ischemic penumbra. We stress that the modern concept of neuroprotection must consider perfusion, the necessary substrate upon which ischemic brain survival depends. We survey the major mechanistic approaches to neuroprotection and review clinical neuroprotection trials, focusing on those phase 3 multicenter clinical trials for acute ischemic stroke that have been completed or terminated. We review the evolution of thrombolytic therapies; consider the lessons learned from the initial, negative multicenter trials of endovascular therapy; and emphasize the highly successful positive trials that have finally established a clinical role for endovascular clot removal. As these studies point to the brain's collateral circulation as key to successful reperfusion, we next review the anatomy and pathophysiology of collateral perfusion as it relates to ischemic infarction, as well as the molecular and genetic influences on collateral development. We discuss the current MR and CT-based diagnostic methods for assessing the collateral circulation and the prognostic significance of collaterals in ischemic stroke, and we consider past and possible future therapeutic directions.

Recanalization and Angiographic Reperfusion Are Both Associated with a Favorable Clinical Outcome in the IMS III Trial

BACKGROUND

Prompt revascularization is the main goal of acute ischemic stroke treatment. We examined which revascularization scale - reperfusion (modified Treatment in Cerebral Infarctions, mTICI) or recanalization (Arterial Occlusive Lesion, AOL) - better predicted the clinical outcome in ischemic stroke participants treated with endovascular therapy (EVT). Additionally, we determined the optimal thresholds for the predictive accuracy of each scale.

METHODS

We included participants from the Interventional Management of Stroke (IMS) III trial with complete occlusion in the internal carotid artery terminus or proximal middle cerebral artery (M1 or M2) who completed EVT within 7 h of symptom onset. The abilities of the AOL and mTICI scales to predict a favorable outcome (defined as a modified Rankin Scale score of 0-2 at 3 months) were compared by receiver operating characteristic analyses. The maximal sensitivity and specificity for each revascularization scale were established.

RESULTS

Among 240 participants who met the study inclusion criteria, 79 (33%) achieved a favorable outcome. Higher scores of mTICI and AOL increased the likelihood of a favorable outcome (2.7% with mTICI 0 vs. 83.3% with mTICI 3, and 3.0% with AOL 0 vs. 43% with AOL 3). The accuracy of mTICI reperfusion and AOL recanalization for a favorable outcome prediction was similar, with optimal thresholds of mTICI 2b/3 and AOL 3, respectively.

CONCLUSION

Reperfusion (mTICI) and recanalization (AOL) predicted a favorable clinical outcome with comparable accuracy in ischemic stroke participants treated with EVT. Optimal revascularization goals to maximize clinical outcome (modified Rankin Scale score of 0-2) consisted of complete recanalization (AOL 3) and reperfusion of at least 50% of the arterial tree of the symptomatic artery (mTICI 2b/3) in the IMS III trial setting.

Stent Retriever-Based Thrombectomy in Octogenarians

BACKGROUND AND AIMS

Stent retriever-based thrombectomy (SRT) may be beneficial in patients with large hemispheric stroke. Previous studies concluded that favorable outcomes are far less frequent after endovascular therapy in older patients but have not explored outcomes in the era of newer-generation stent retrievers.

MATERIALS AND METHODS

Consecutive patients with large hemispheric stroke treated with SRT were included. We compared neurological and functional outcomes between patients younger and older than 80.

RESULTS

We included 16 patients older than 80 (22.5%, mean age 84.1 ± 4.4, 56% females) and compared them to 55 patients that were younger than 80 (77.5%, mean age 63.1 ± 12.5, 51% females). Risk factor profile, admission neurological severity, stroke etiology and procedure-related variables including excellent target vessel recanalization did not differ between the groups. Favorable outcome at 90 days (modified Rankin score ≤2) was more common in younger patients (77 vs. 23%; p = 0.031). In contrast, mortality rates were higher in octogenarians (40 vs. 7%; p = 0.01). Logistic regression analysis adjusting for neurological severity and collateral state identified age over 80 (odds ratio, OR 0.15, 95% CI 0.03-0.75; p = 0.02) and reperfusion state (OR 7.4, 95% CI 1.1-49.9; p = 0.04) as significant modifiers of favorable outcome. Similarly, age over 80 was identified as a positive predictor of mortality (OR 8.1, 95% CI 1.8-36.7; p = 0.007).

CONCLUSIONS

Octogenarians have higher chances of mortality and lower probability of achieving functional independence even after SRT. Nevertheless, because some elderly patients do achieve favorable outcomes, the cost-effectiveness of SRT in this population needs to be further studied.

Endovascular treatment versus medical care alone for ischaemic stroke: systematic review and meta-analysis

OBJECTIVES

To evaluate the efficacy and safety of endovascular treatment, particularly adjunctive intra-arterial mechanical thrombectomy, in patients with ischaemic stroke.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, SciELO, LILACS, and clinical trial registries from inception to December 2015. Reference lists were crosschecked.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials in adults aged 18 or more with ischaemic stroke comparing endovascular treatment, including thrombectomy, with medical care alone, including intravenous recombinant tissue plasminogen activator (rt-PA). Trial endpoints were functional outcome (modified Rankin scale scores of ≤2) and mortality at 90 days after onset of symptoms. No language or time restrictions applied.

RESULTS

10 randomised controlled trials (n=2925) were included. In pooled analysis endovascular treatment, including thrombectomy, was associated with a higher proportion of patients experiencing good (modified Rankin scale scores ≤2) and excellent (scores ≤1) outcomes 90 days after stroke, without differences in mortality or rates for symptomatic intracranial haemorrhage, compared with patients randomised to medical care alone, including intravenous rt-PA. Heterogeneity was high among studies. The more recent studies (seven randomised controlled trials, published or presented in 2015) proved better suited to evaluate the effect of adjunctive intra-arterial mechanical thrombectomy on its index disease owing to more accurate patient selection, intravenous rt-PA being administered at a higher rate and earlier, and the use of more efficient thrombectomy devices. In most of these studies, more than 86% of the patients were treated with stent retrievers, and rates of recanalisation were higher (>58%) than previously reported. Subgroup analysis of these seven studies yielded a risk ratio of 1.56 (95% confidence interval 1.38 to 1.75) for good functional outcomes and 0.86 (0.69 to 1.06) for mortality, without heterogeneity among the results of the studies. All trials were open label. Risk of bias was moderate across studies. The full results of two trials are yet to be published.

CONCLUSIONS

Moderate to high quality evidence suggests that compared with medical care alone in a selected group of patients endovascular thrombectomy as add-on to intravenous thrombolysis performed within six to eight hours after large vessel ischaemic stroke in the anterior circulation provides beneficial functional outcomes, without increased detrimental effects.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015019340.

Inter-rater Agreement in Three Perfusion-Computed Tomography Evaluation Methods before Endovascular Therapy for Acute Ischemic Stroke

PURPOSE

There is ongoing debate on which method of perfusion computed tomography (PCT) evaluation in ischemic stroke is the most appropriate for improved selection of patients for endovascular treatment. We sought to test different assessment methods for inter-rater reliability.

METHODS

Twenty-six patients were enrolled prospectively before endovascular therapy for acute anterior circulation ischemic stroke. Three raters experienced in stroke imaging and blinded to other imaging and clinical information independently analyzed 22 technically successful PCT scans according to 3 prespecified assessment methods applied to cerebral blood flow (CBF)/cerebral blood volume (CBV) and time-to-peak (TTP) maps: (1) visual mismatch estimate (VME), (2) Alberta Stroke Program Early CT Score perfusion method (ASPECTS-PCT), and (3) quantitative perfusion ratios (qPRs): RCBF, RCBV, RTTP. Inter-rater agreement was assessed with Cohen's kappa, intraclass correlation coefficients (ICC), Bland-Altman plots, and global and descriptive statistics.

RESULTS

Significant differences between raters were found with VME and ASPECTS-PCT (P < .001) but with qPRs only for CBV (P = .03). Inter-rater agreement for VME was at best moderate by kappa statistics (.51); moderate by ICC for all parametric maps of ASPECTS-PCT (.56-.62), strong for RTTP (.76), and excellent for RCBF (.92) and RCBV (.86). Pairwise comparisons revealed less scattering of individual values with qPRs and less deviation of mean differences from 0, suggesting minor systematic deviation by any 1 rater as compared with VME or ASPECTS-PCT.

CONCLUSION

PCT evaluation methods used before endovascular therapy for acute anterior circulation stroke are subject to substantial inter-rater disagreement. QPRs in PCT evaluation had better inter-rater reliability than the often used VME and ASPECTS-PCT assessment.

Mechanical Recanalization following i.v. Thrombolysis: A Retrospective Analysis regarding Secondary Hemorrhagic Infarctions and Parenchymal Hematomas

Introduction. In acute stroke by occlusion of the proximal medial cerebral artery (MCA) or the distal internal carotid artery, intravenous thrombolysis is an established treatment. Another option is mechanical recanalization. It remains unclear if the combination of both methods poses an additional bleeding risk. The aim of this retrospective analysis is to determine the proportion of hemorrhagic infarctions and parenchymal hematomas. Methods. Inclusion criteria were an occlusion of the carotid T or proximal MCA treated with full dose thrombolysis and mechanical recanalization. 31 patients were selected. Devices used were Trevo, Penumbra Aspiration system, Penumbra 3D Retriever, and Revive. The initial control by computed tomography was carried out with a mean delay to intervention of 10.9 hours (SD: 8.5 hours). Results. A slight hemorrhagic infarction (HI1) was observed in 2/31 patients, and a more severe HI2 occurred in two cases. A smaller parenchymal hematoma (PH1) was not seen and a space-occupying PH2 was seen in 2/31 cases. There was no significant difference in the probability of intracranial bleeding after successful (thrombolysis in cerebral infarctions 2b and 3) or unsuccessful recanalization. Conclusion. The proportion of intracranial bleeding using mechanical recanalization following intravenous thrombolysis appears comparable with reports using thrombolysis alone.

Endovascular Therapy Is Effective and Safe for Patients With Severe Ischemic Stroke: Pooled Analysis of Interventional Management of Stroke III and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands Data

BACKGROUND AND PURPOSE

We assessed the effect of endovascular treatment in acute ischemic stroke patients with severe neurological deficit (National Institutes of Health Stroke Scale score, ≥20) after a prespecified analysis plan.

METHODS

The pooled analysis of the Interventional Management of Stroke III (IMS III) and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands (MR CLEAN) trials included participants with an National Institutes of Health Stroke Scale score of ≥20 before intravenous tissue-type plasminogen activator (tPA) treatment (IMS III) or randomization (MR CLEAN) who were treated with intravenous tPA ≤3 hours of stroke onset. Our hypothesis was that participants with severe stroke randomized to endovascular therapy after intravenous tPA would have improved 90-day outcome (distribution of modified Rankin Scale scores), when compared with those who received intravenous tPA alone.

RESULTS

Among 342 participants in the pooled analysis (194 from IMS III and 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared with the intravenous tPA group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.66). In the logistic regression model of the dichotomous outcome (modified Rankin Scale score, 0-2, or functional independence), the endovascular group had superior outcomes (adjusted odds ratio, 1.97; 95% confidence interval, 1.09-3.56). Functional independence (modified Rankin Scale score, ≤2) at 90 days was 25% in the endovascular group when compared with 14% in the intravenous tPA group.

CONCLUSIONS

Endovascular therapy after intravenous tPA within 3 hours of symptom onset improves functional outcome at 90 days after severe ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424 (IMS III) and ISRCTN10888758 (MR CLEAN).

Outcome Differences between Intra-Arterial Iso- and Low-Osmolality Iodinated Radiographic Contrast Media in the Interventional Management of Stroke III Trial

BACKGROUND AND PURPOSE

Intracarotid arterial infusion of nonionic, low-osmolal iohexol contrast medium has been associated with increased intracranial hemorrhage in a rat middle cerebral artery occlusion model compared with saline infusion. Iso-osmolal iodixanol (290 mOsm/kg H2O) infusion demonstrated smaller infarcts and less intracranial hemorrhage compared with low-osmolal iopamidol and saline. No studies comparing iodinated radiographic contrast media in human stroke have been performed, to our knowledge. We hypothesized that low-osmolal contrast media may be associated with worse outcomes compared with iodixanol in the Interventional Management of Stroke III Trial (IMS III).

MATERIALS AND METHODS

We reviewed prospective iodinated radiographic contrast media data for 133 M1 occlusions treated with endovascular therapy. We compared 5 prespecified efficacy and safety end points (mRS 0-2 outcome, modified TICI 2b-3 reperfusion, asymptomatic and symptomatic intracranial hemorrhage, and mortality) between those receiving iodixanol (n = 31) or low-osmolal contrast media (n = 102). Variables imbalanced between iodinated radiographic contrast media types or associated with outcome were considered potential covariates for the adjusted models. In addition to the iodinated radiographic contrast media type, final covariates were those selected by using the stepwise method in a logistic regression model. Adjusted relative risks were then estimated by using a log-link regression model.

RESULTS

Of baseline or endovascular therapy variables potentially linked to outcome, prior antiplatelet agent use was more common and microcatheter iodinated radiographic contrast media injections were fewer with iodixanol. Relative risk point estimates are in favor of iodixanol for the 5 prespecified end points with M1 occlusion. The percentage of risk differences are numerically greater for microcatheter injections with iodixanol.

CONCLUSIONS

While data favoring the use of iso-osmolal iodixanol for reperfusion of M1 occlusion following IV rtPA are inconclusive, potential pathophysiologic mechanisms suggesting clinical benefit warrant further investigation.

Endovascular stroke therapy with the Aperio thrombectomy device

BACKGROUND

The pharmaceutical therapy for acute ischemic stroke has shortcomings in reopening large vessels and dissolving long thrombi, and endovascular treatment has been found to provide added value. The Aperio thrombectomy device showed promising results in an experimental study. The purpose of this study was to evaluate the device clinically.

METHODS

119 patients with acute stroke were treated in nine centers using the Aperio thrombectomy device. Target vessel, diameter, thrombus length, procedure time, recanalization, number of deployments, additional use of anticoagulants, complications, and the use of additional devices were assessed.

RESULTS

The median thrombus length was 15 mm (range 1.5-20 mm) and the average time from device insertion to recanalization was 30 min (range 5-120 min). Blood flow restoration (Thrombolysis In Cerebral Infarction (TICI) 2-3) was achieved in 85%. In the majority of cases complete clot removal was achieved (TICI 0, 12%; TICI 1, 2%; TICI 2a, 14%; TICI 2b, 18%; TICI 3, 53%). The median number of deployments was 2 (range 1-6). Twelve procedural complications (10%) occurred.

CONCLUSIONS

The Aperio thrombectomy device seems to be an effective and adequately safe tool for reopening occluded cerebral arteries in the setting of acute stroke.

Impact of General Anesthesia on Safety and Outcomes in the Endovascular Arm of Interventional Management of Stroke (IMS) III Trial

BACKGROUND AND PURPOSE

General anesthesia (GA) for endovascular therapy (EVT) of acute ischemic stroke may be associated with worse outcomes.

METHODS

The Interventional Management of Stroke III trial randomized patients within 3 hours of acute ischemic stroke onset to intravenous tissue-type plasminogen activator±EVT. GA use within 7 hours of stroke onset was recorded per protocol. Good outcome was defined as 90-day modified Rankin Scale ≤2. A multivariable analysis adjusting for dichotomized National Institutes of Health Stroke Scale (NIHSS; 8-19 versus ≥20), age, and time from onset to groin puncture was performed.

RESULTS

Four hundred thirty-four patients were randomized to EVT, 269 (62%) were treated under local anesthesia and 147 (33.9%) under GA; 18 (4%) were undetermined. The 2 groups were comparable except for median baseline NIHSS (16 local anesthesia versus 18 GA; P<0.0001). The GA group was less likely to achieve a good outcome (adjusted relative risk, 0.68; confidence interval, 0.52-0.90; P=0.0056) and had increased in-hospital mortality (adjusted relative risk, 2.84; confidence interval, 1.65-4.91; P=0.0002). Those with medically indicated GA had worse outcomes (adjusted relative risk, 0.49; confidence interval, 0.30-0.81; P=0.005) and increased mortality (relative risk, 3.93; confidence interval, 2.18-7.10; P<0.0001) with a trend for higher mortality with routine GA. There was no significant difference in the adjusted risks of subarachnoid hemorrhage (P=0.32) or symptomatic intracerebral hemorrhage (P=0.37).

CONCLUSIONS

GA was associated with worse neurological outcomes and increased mortality in the EVT arm; this was primarily true among patients with medical indications for GA. Relative risk estimates, though not statistically significant, suggest reduced risk for subarachnoid hemorrhage and symptomatic intracerebral hemorrhage under local anesthesia. Although the reasons for these associations are not clear, these data support the use of local anesthesia when possible during EVT.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424.

Twelve-Month Clinical and Quality-of-Life Outcomes in the Interventional Management of Stroke III Trial

BACKGROUND AND PURPOSE

Randomized trials have indicated a benefit for endovascular therapy in appropriately selected stroke patients at 3 months, but data regarding outcomes at 12 months are currently lacking.

METHODS

We compared functional and quality-of-life outcomes at 12 months overall and by stroke severity in stroke patients treated with intravenous tissue-type plasminogen activator followed by endovascular treatment as compared with intravenous tissue-type plasminogen activator alone in the Interventional Management of Stroke III Trial. The key outcome measures were a modified Rankin Scale score ≤2 (functional independence) and the Euro-QoL EQ-5D, a health-related quality-of-life measure.

RESULTS

656 subjects with moderate-to-severe stroke (National Institutes of Health Stroke Scale ≥8) were enrolled at 58 centers in the United States (41 sites), Canada (7), Australia (4), and Europe (6). There was an interaction between treatment group and stroke severity in the repeated measures analysis of modified Rankin Scale ≤2 outcome (P=0.039). In the 204 participants with severe stroke (National Institutes of Health Stroke Scale ≥20), a greater proportion of the endovascular group had a modified Rankin Scale ≤2 (32.5%) at 12 months as compared with the intravenous tissue-type plasminogen activator group (18.6%, P=0.037); no difference was seen for the 452 participants with moderately severe strokes (55.6% versus 57.7%). In participants with severe stroke, the endovascular group had 35.2 (95% confidence interval: 2.1, 73.3) more quality-adjusted-days over 12 months as compared with intravenous tissue-type plasminogen activator alone.

CONCLUSIONS

Endovascular therapy improves functional outcome and health-related quality-of-life at 12 months after severe ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424.

State-of-the-art endovascular treatment of acute ischemic stroke

Stroke is the third leading cause of death in the USA. An estimated 795,000 new or recurrent stroke events occur annually, mostly ischemic in nature. Arterial recanalization and subsequent reperfusion performed shortly after symptom onset can help to restore brain function in acute ischemic stroke (AIS). The only treatment currently approved by the United States Food and Drug Administration is intravenous tissue plasminogen activator, administered within 4.5 h of symptom onset. However, this short window often precludes effective intervention. Mechanical neurothrombectomy devices offer many potential advantages over pharmacologic thrombolysis, including more rapid achievement of recanalization, enhanced efficacy in treating large-vessel occlusions, and a potentially lower risk of hemorrhagic events. The goal of this chapter is to describe the state-of-the-art neurothrombectomy devices and stenting techniques for endovascular treatment of acute ischemic stroke, as well as to highlight recent advances in reperfusion therapies. Ongoing clinical trials, some with randomized, controlled designs, are included.

Lessons learnt from recent endovascular stroke trials: finding a way to move forward

The advent of stentrievers provided momentum for endovascular stroke therapy. Hopes were dampened after three randomized trials showed no clear benefit of endovascular therapy. This review discusses the results of these trials results and shortcomings. A detailed discussion will follow on the design, conduct and analysis of current and future endovascular stroke trials. Steps to improve the workflow of acute stroke cases from the time they enter the emergency department until endovascular reperfusion is achieved can significantly shorten the time from onset to successful reperfusion. These factors in addition to using novel approaches to analyze data and minimize delays caused by the consent process are perceived to be sufficient to demonstrate the efficacy of endovascular stroke therapy.

Reperfusion therapies of acute ischemic stroke: potentials and failures

Over the past 20 years, clinical research has focused on the development of reperfusion therapies for acute ischemic stroke (AIS), which include the use of systemic intravenous thrombolytics (alteplase, desmoteplase, or tenecteplase), the augmentation of systemic intravenous recanalization with ultrasound, the bridging of intravenous with intra-arterial thrombolysis, the use of multi-modal approaches to reperfusion including thrombectomy and thromboaspiration with different available retrievers. Clinical trials testing these acute reperfusion therapies provided novel insight regarding the comparative safety and efficacy, but also raised new questions and further uncertainty on the field. Intravenous alteplase (tPA) remains the fastest and easiest way to initiate acute stroke reperfusion treatment, and should continue to be the first-line treatment for patients with AIS within 4.5 h from onset. The use of tenecteplase instead of tPA and the augmentation of systemic thrombolysis with ultrasound are both novel therapeutical modalities that may emerge as significant options in AIS treatment. Endovascular treatments for AIS are rapidly evolving due to technological advances in catheter-based interventions and are currently emphasizing speed in order to result in timely restoration of perfusion of still-salvageable, infarcted brain tissue, since delayed recanalization of proximal intracranial occlusions has not been associated with improved clinical outcomes. Comprehensive imaging protocols in AIS may enable better patient selection for endovascular interventions and for testing multi-modal combinatory strategies.

Endovascular revascularization results in IMS III: intracranial ICA and M1 occlusions

BACKGROUND

Interventional Management of Stroke III did not show that combining IV recombinant tissue plasminogen activator (rt-PA) with endovascular therapies (EVTs) is better than IV rt-PA alone.

OBJECTIVE

To report efficacy and safety results for EVT of intracranial internal carotid artery (ICA) and middle cerebral artery trunk (M1) occlusion.

METHODS

Five revascularization methods for persistent occlusions after IV rt-PA treatment were evaluated for prespecified primary and secondary endpoints, after accounting for differences in key baselines variables using propensity scores. Revascularization was scored using the arterial occlusive lesion (AOL) and the modified Thrombolysis in Cerebral Ischemia (mTICI) scores.

RESULTS

EVT of 200 subjects with intracranial ICA or M1 occlusion resulted in 81.5% AOL 2-3 recanalization, in addition to 76% mTICI 2-3 and 42.5% mTICI 2b-3 reperfusion. Adverse events included symptomatic intracranial hemorrhage (SICH) (8.0%), vessel perforations (1.5%), and new emboli (14.9%). EVT techniques used were standard microcatheter n=51; EKOS n=14; Merci n=77; Penumbra n=39; Solitaire n=4; multiple n=15. Good clinical outcome was associated with both TICI 2-3 and TICI 2b-3 reperfusion. Neither modified Rankin scale (mRS) 0-2 (28.5%), nor 90-day mortality (28.5%), nor asymptomatic ICH (36.0%) differed among revascularization methods after propensity score adjustment for subjects with intracranial ICA or M1 occlusion.

CONCLUSIONS

Good clinical outcome was associated with good reperfusion for ICA and M1 occlusion. No significant differences in efficacy or safety among revascularization methods were demonstrated after adjustment. Lack of high-quality reperfusion, adverse events, and prolonged time to treatment contributed to lower-than-expected mRS 0-2 outcomes and study futility compared with IV rt-PA.

TRIAL REGISTRATION NUMBER

NCT00359424.

Evolution of practice during the Interventional Management of Stroke III Trial and implications for ongoing trials

BACKGROUND AND PURPOSE

We explored changes in the patient population and practice of endovascular therapy during the course of the Interventional Management of Stroke (IMS) III Trial.

METHODS

Changes in baseline characteristics, use of baseline CT angiography, treatment times and specifics, and outcomes were compared between the first 4 protocols and the fifth and final protocol.

RESULTS

Compared with subjects treated in the first 4 protocol versions (n=610), subjects treated in fifth and final protocol (n=46) were older (75 versus 68 years, P<0.0002) and less likely to have a pretreatment Rankin of 0 (76% versus 89%, P=0.01), were more likely to have a pretreatment CT angiography (65% versus 45%, P=0.009), had quicker median times in the endovascular arm from onset to start of intra-arterial therapy (209 versus 250 minutes, P=0.002) and to reperfusion (269 versus 344 minutes, P<0.0001), had a higher mean dose of total tissue-type plasminogen activator in the endovascular arm (74.0 versus 63.7 mg, P<0.0001), and were less likely to receive intra-arterial tissue-type plasminogen activator as part of the endovascular procedure (16% versus 44%, P=0.015). There were no significant differences in functional and safety outcomes between subjects treated in the 2 treatments arms in either the first 4 protocols or fifth protocol although the small sample size in the fifth protocol provided limited power.

CONCLUSIONS

Endovascular technology and diagnostic approaches to acute stroke patients changed substantially during the IMS III Trial. Efforts to decrease the time to delivery of endovascular therapy were successful.

Republished: Society for Neuroscience in Anesthesiology and Critical Care expert consensus statement: Anesthetic management of endovascular treatment for acute ischemic stroke

Literature on the anesthetic management of endovascular treatment of acute ischemic stroke (AIS) is limited. Anesthetic management during these procedures is still mostly dependent on individual or institutional preferences. Thus, the Society of Neuroscience in Anesthesiology and Critical Care (SNACC) created a task force to provide expert consensus recommendations on anesthetic management of endovascular treatment of AIS. The task force conducted a systematic literature review (up to August 2012). Because of the limited number of research articles relating to this subject, the task force solicited opinions from experts in this area. The task force created a draft consensus statement based on the available data. Classes of recommendations and levels of evidence were assigned to articles specifically addressing anesthetic management during endovascular treatment of stroke using the standard American Heart Association evidence rating scheme. The draft consensus statement was reviewed by the Task Force, SNACC Executive Committee and representatives of Society of NeuroInterventional Surgery (SNIS) and Neurocritical Care Society (NCS) reaching consensus on the final document. For this consensus statement the anesthetic management of endovascular treatment of AIS was subdivided into 12 topics. Each topic includes a summary of available data followed by recommendations. This consensus statement is intended for use by individuals involved in the care of patients with acute ischemic stroke, such as anesthesiologists, interventional neuroradiologists, neurologists, neurointensivists and neurosurgeons.