Intravenous thrombolysis outcomes in patients presenting with large vessel acute ischemic strokes--CT angiography-based prognosis

Is time really brain in stroke therapy?: A meta-analysis of mechanical thrombectomy up to 155 h post ictus

BACKGROUND AND OBJECTIVES

Mechanical thrombectomy (MT) has been established as the gold standard of treatment for patients with Acute Ischemic Stroke (AIS) who present up to 6 h after the onset of the stroke. Recently, the DEFUSE-3 and DAWN trials established the safety of starting the MT procedure up to 16 and 24 h after the patient was last seen well, respectively. The purpose of this study is to assess the safety and functional effects of thrombectomy in individuals with AIS detected at a late stage (> 24 h).

MATERIALS AND METHODS

PubMed, Web of Science, Embase, and Cochrane databases were thoroughly searched for research on MT in patients in the extremely late time window after AIS. The primary outcomes were symptomatic cerebral hemorrhage, 90-day mortality, Thrombolysis in Cerebral Infarction (TICI) 2b-3, and Modified Rankin Scale (mRS) 0-2.

RESULTS

Our study included fifteen studies involving a total of 1,221 patients who presented with AIS and an extended time window. The primary outcome of interest was the favorable functional outcome, mRS 0-2 at 90 days. The pooled proportion for this outcome was 45% (95% confidence interval 34-58%). Other outcomes included the TICI 2b or 3 (successful recanalization), which was reported in 12 studies and had a 79% incidence in the study population (95% CI 68-87%). Complications included: symptomatic intracranial hemorrhage (sICH), which revealed an incidence of 7% in the study population (95% CI 5-10%); and 90-day mortality, which reported a 27% incidence (95% CI 24-31%). In addition, we conducted a comparative analysis between endovascular treatment and standard medical therapy.

CONCLUSION

Our meta-analysis provides evidence that supports the need of further randomized and prospective clinical trials to better assess the effectiveness and safety of MT in these patients.

Mechanical Thrombectomy with or without Intravenous Thrombolysis in Acute Ischemic Stroke: A Meta-Analysis for Randomized Controlled Trials

INTRODUCTION

The combination of mechanical thrombectomy (MT) and intravenous thrombolysis (IVT) is more effective than IVT alone in patients with large vessel occlusion, which has been proven in recent studies. However, there are still debates over whether IVT benefits patients treated with only direct mechanical thrombectomy (dMT).

METHODS

PubMed, Embase, and Cochrane Library were searched on June 15, 2021, for randomized controlled trials (RCTs). Seven RCTs with 2,143 patients were enrolled in our study.

RESULTS

MT combined with IVT had comparable efficacy and safety outcome compared with dMT in proximal anterior circulation occlusion at 90 days. For the primary outcome, pooled data showed no significant difference in the modified Rankin Scale (mRS) 0-2 at 90 days between the dMT and MT+IVT groups (pooled odds ratio 0.96, 95% confidence interval, 0.79, 1.17, p = 0.39). As for the mRS score 0-1 at 90 days, the degree of benefit conferred by dMT was substantial: for every 100 patients treated, the number of patients which had an excellent outcome in the dMT group was 10 higher than that of the MT+IVT group.

CONCLUSION

In this meta-analysis including 7 RCTs, MT had comparable consequences to bridging treatment in efficacy and safety outcomes for patients with ischemic stroke caused by the occlusion of proximal anterior circulation, irrespective of geographical location. These findings support the adoption of dMT in acute ischemic stroke treatments and have higher cost-effectiveness in global applications.

Utilization of CT angiography of the head and neck in the era of endovascular therapy for acute ischemic stroke: a retrospective study

PURPOSE

To describe the impact of a new institutional Code Stroke protocol on ordering volume of head and neck CT angiographies (CTA), and to determine the number and proportion of these studies that resulted in an endovascular or surgical intervention.

METHODS

Clinical and administrative data was collected on all head and neck CTAs ordered within the ED at two high-volume community hospitals and an affiliated urgent care centre during the 6-year period between January 1, 2014, and December 31, 2019. Of those patients who underwent CTA, we identified those who were then transferred to a regional stroke centre for consideration of EVT and those who underwent carotid endarterectomy or stenting within 14 days.

RESULTS

A total of 4719 CTAs were ordered during the 6-year period. There was nearly a tenfold rise in the yearly number of CTAs ordered per 10,000 ED visits, from 5.3 (in 2014) to 53.1 (in 2019). A total of 164 patients who underwent CTAs (3.5%) were ultimately transferred to a regional tertiary care centre, of whom 43 (0.9%) were transferred to a regional stroke centre for consideration of EVT. A total of 61 (1.3%) patients underwent a carotid intervention within 14 days.

CONCLUSION

Little is known of the impacts on healthcare resources that have resulted from the system-wide changes made necessary by the widespread adoption of EVT. Our study shows that at our site, these system changes have resulted in large increases in CTA utilization with very small numbers of patients ultimately undergoing EVT or carotid intervention.

IV tPA given in the golden hour for emergent large vessel occlusion stroke improves recanalization rates and clinical outcomes

BACKGROUND

Early thrombolysis for acute ischemic stroke (AIS) due to emergent large vessel occlusion (ELVO) is associated with better clinical outcome. This is thought to be due to greater tissue salvage with earlier recanalization. We explored whether ultra-early administration of intravenous tissue plasminogen activator (IV tPA) within 60 min (Golden Hour) of symptom onset for AIS due to ELVO is associated with a higher rate of recanalization.

METHODS

We performed a retrospective analysis of recanalization rates and clinical outcomes in patients with AIS due to ELVO treated with IV tPA, comparing patients who received IV tPA within 60 min of stroke symptom onset with those treated beyond 60 min.

RESULTS

Between January 2013 and December 2016, 158 patients with AIS due to ELVO were treated with IV tPA. Of these, 25 (15.8%) patients received IV tPA within 60 min of stroke symptom onset, while the remaining 133 (84.2%) patients received IV tPA beyond 60 min. The ultra-early treatment group was found to have a higher rate of complete recanalization (28.0% vs 6.8%, 95% CI 1.78-16.63), better chance of early neurological improvement (76.0% vs 50.4%, 95% CI 1.16-8.65), favorable clinical outcomes (mRS ≤ 2 or return to premorbid mRS) (65.0% vs 36.8%, 95% CI 1.42-9.34), and lower mortality (5% vs 31.1%, 95% CI 0.01-0.74) at 90-day follow-up compared to the later treatment group.

CONCLUSION

Our data suggest that ultra-early administration of IV tPA significantly improves recanalization rates and clinical outcomes in patients with AIS due to ELVO.

Thrombolysis outcomes according to arterial characteristics of acute ischemic stroke by alteplase dose and blood pressure target

BACKGROUND

We explored the influence of low-dose intravenous alteplase and intensive blood pressure lowering on outcomes of acute ischemic stroke according to status/location of vascular obstruction in participants of the Enhanced Control of Hypertension and Thrombolysis Stroke Study (ENCHANTED).

METHODS

ENCHANTED was a multicenter, quasi-factorial, randomized trial to determine efficacy and safety of low- versus standard-dose intravenous alteplase and intensive- versus guideline-recommended blood pressure lowering in acute ischemic stroke patients. In those who had baseline computed tomography or magnetic resonance imaging angiography, the degree of vascular occlusion was grouped according to being no (NVO), medium (MVO), or large (LVO). Logistic regression models were used to determine 90-day outcomes (modified Rankin scale [mRS] shift [primary], other mRS cut-scores, intracranial hemorrhage, early neurologic deterioration, and recanalization) by vascular obstruction status/site. Heterogeneity in associations for outcomes across subgroups was estimated by adding an interaction term to the models.

RESULTS

There were 940 participants: 607 in alteplase arm only, 243 in blood pressure arm only, and 90 assigned to both arms. Compared to the NVO group, functional outcome was worse in LVO (mRS shift, adjusted OR [95% CI] 2.13 [1.56-2.90]) but comparable in MVO (1.34 [0.96-1.88]) groups. There were no differences in associations of alteplase dose or blood pressure lowering and outcomes across NVO/MVO/LVO groups (mRS shift: low versus standard alteplase dose 0.84 [0.54-1.30]/0.48 [0.25-0.91]/0.99 [0.75-2.09], P_interaction = 0.28; intensive versus standard blood pressure lowering 1.32 [0.74-2.38]/0.78 [0.31-1.94]/1.24 [0.64-2.41], P_interaction = 0.41), except for a borderline significant difference for intensive blood pressure lowering and increased early neurologic deterioration (0.63 [0.14-2.72]/0.17 [0.02-1.47]/2.69 [0.90-8.04], P_interaction = 0.05).

CONCLUSIONS

Functional outcome by dose of alteplase or intensity of blood pressure lowering is not modified by vascular obstruction status/site according to analyses from ENCHANTED, although these results are compromised by low statistical power.Clinical Trial Registration: http://www.clinicaltrials.gov. Unique identifiers: NCT01422616.

The prognostic significance of large vessel occlusion in stroke patients treated by intravenous thrombolysis

Purpose

According to guidelines, to shorten the treatment window, acute ischaemic stroke (AIS) treatment by intravenous thrombolysis (IVT) can be done based on the results of head computed tomography (CT) without contrast. The impact of large vessel occlusion (LVO) on computed tomography angiography (CTA) in stroke prognosis in patients treated IVT or IVT and mechanical thrombectomy (MT), where indicated, has not yet been studied systematically. We investigated the influence of LVO in consecutive AIS patients on haemorrhagic transformation (HT) on CT 24 h after treatment, mRS < 2 on discharge (unfavourable outcome), and in-hospital mortality.

Material and methods

We analysed several parameters within 24 h after AIS: demographics, risk factors, mRS score pre-stroke, NIHSS upon admission and 24 h later, several clinical and biochemical parameters, and chronic treatment.

Results

We registered 1209 patients, of whom 362 (29.9%) received IVT and 108 had MT, where indicated. Admission CTA showed LVO in 197 patients (54.4%). Multivariate regression analysis showed that the presence of LVO and lower delta NIHSS (NIHSS on admission minus NIHSS 24 hours later) were independent parameters affecting HT risk. Multivariate analysis showed that the presence LVO and also older age, female sex, lower delta NIHSS, HT, stroke-associated infection, CRP levels ≥ 10 mg/L, and higher WBC count affected unfavourable outcome on discharge. LVO did not affect in-hospital mortality.

Conclusions

LVO in AIS patients treated by IVT or IVT and MT affects the risk of HT and unfavourable short-term outcome but not in-hospital mortality.

Extent of FLAIR Hyperintense Vessels May Modify Treatment Effect of Thrombolysis: A Post hoc Analysis of the WAKE-UP Trial

Background and Aims: Fluid-attenuated inversion recovery (FLAIR) hyperintense vessels (FHVs) on MRI are a radiological marker of vessel occlusion and indirect sign of collateral circulation. However, the clinical relevance is uncertain. We explored whether the extent of FHVs is associated with outcome and how FHVs modify treatment effect of thrombolysis in a subgroup of patients with confirmed unilateral vessel occlusion from the randomized controlled WAKE-UP trial.

Methods: One hundred sixty-five patients were analyzed. Two blinded raters independently assessed the presence and extent of FHVs (defined as the number of slices with visible FHV multiplied by FLAIR slice thickness). Patients were then separated into two groups to distinguish between few and extensive FHVs (dichotomization at the median <30 or ≥30).

Results: Here, 85% of all patients (n = 140) and 95% of middle cerebral artery (MCA) occlusion patients (n = 127) showed FHVs at baseline. Between MCA occlusion patients with few and extensive FHVs, no differences were identified in relative lesion growth (p = 0.971) and short-term [follow-up National Institutes of Health Stroke Scale (NIHSS) score; p = 0.342] or long-term functional recovery [modified Rankin Scale (mRS) <2 at 90 days poststroke; p = 0.607]. In linear regression analysis, baseline extent of FHV (defined as a continuous variable) was highly associated with volume of hypoperfused tissue (β = 2.161; 95% CI 0.96–3.36; p = 0.001). In multivariable regression analysis adjusted for treatment group, stroke severity, lesion volume, occlusion site, and recanalization, FHV did not modify functional recovery. However, in patients with few FHVs, the odds for good functional outcome (mRS) were increased in recombinant tissue plasminogen activator (rtPA) patients compared to those who received placebo [odds ratio (OR) = 5.3; 95% CI 1.2–24.0], whereas no apparent benefit was observed in patients with extensive FHVs (OR = 1.1; 95% CI 0.3–3.8), p-value for interaction was 0.11.

Conclusion: While the extent of FHVs on baseline did not alter the evolution of stroke in terms of lesion progression or functional recovery, it may modify treatment effect and should therefore be considered relevant additional information in those patients who are eligible for intravenous thrombolysis.

Clinical Trial Registration: Main trial (WAKE-UP): ClinicalTrials.gov, NCT01525290; and EudraCT, 2011-005906-32. Registered February 2, 2012.

Triage and systems of care in stroke

There has been increasing adoption of endovascular stroke treatment in the United States following multiple clinical trials demonstrating superior efficacy. Next steps in enhancing this treatment include an analysis and development of stroke systems of care geared toward efficient delivery of endovascular and comprehensive stroke care. The chapter presents epidemiological data and an overview of the current state of stroke delivery and potential improvements for the future in the light of clinical data.

Endovascular Treatment of Acute Ischemic Stroke

PURPOSE OF REVIEW

This article reviews the actual indications for mechanical thrombectomy in patients with acute ischemic stroke and how the opportunities for endovascular therapy can be expanded by using the concept of clinical-imaging or perfusion-imaging mismatch (as a surrogate for salvageable tissue) rather than time of ischemia.

RECENT FINDINGS

Six randomized controlled trials undoubtedly confirmed the benefits of using endovascular thrombectomy on the clinical outcome of patients with stroke with large vessel occlusion within 6 hours from symptom onset compared with those receiving only standard medical care. In a meta-analysis of individual patient data, the number needed to treat with endovascular thrombectomy to reduce disability by at least one level on the modified Rankin Scale for one patient was 2.6. Recently, the concept of "tissue window" versus time window has proved useful for selecting patients for mechanical thrombectomy up to 24 hours from symptom onset. The DAWN (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention) trial included patients at a median of 12.5 hours from onset and showed the largest effect in functional outcome ever described in any acute stroke treatment trial (35.5% increase in functional independence). In DEFUSE 3 (Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution 3), patients treated with mechanical thrombectomy at a median of 11 hours after onset had a 28% increase in functional independence and an additional 20% absolute reduction in death or severe disability.

SUMMARY

For patients with acute ischemic stroke and a large vessel occlusion in the proximal anterior circulation who can be treated within 6 hours of stroke symptom onset, mechanical thrombectomy with a second-generation stent retriever or a catheter aspiration device should be indicated regardless of whether the patient received treatment with intravenous (IV) recombinant tissue plasminogen activator (rtPA) in patients with limited signs of early ischemic changes on neuroimaging. Two clinical trials completely disrupted the time window concept in acute ischemic stroke, showing excellent clinical outcomes in patients treated up to 24 hours from symptom onset. Time of ischemia is, on average, a good biomarker for tissue viability; however, the window of opportunity for treatment varies across different individuals because of a range of compensatory mechanisms. Adjusting time to the adequacy of collateral flow leads to the concept of tissue window, a paradigm shift in stroke reperfusion therapy.

Functional Outcome After Mechanical Thrombectomy with or without Previous Thrombolysis

INTRODUCTION

Combined intravenous therapy (IVT) and mechanical thrombectomy (MT) is the standard treatment for acute ischemic stroke (AIS) with large vessel occlusion (LVO). However, the use of  IVT before MT is recently being questioned.

OBJECTIVES

To compare patients treated with IVT before MT with those treated with MT alone, in a real-world scenario.

METHODS

Retrospective analysis of AIS patients with LVO of the anterior circulation who underwent MT, with or without previous IVT, between 2016 and 2018.

RESULTS

A total of 524 patients were included (347 submitted to IVT+MT; 177 to MT alone). No differences between groups were found except for a higher time from stroke onset to CT and to groin puncture in the MT group (297.5 min vs 115.0 min and 394.0 min vs 250.0 min respectively, p < 0.001). Multivariable analysis showed that age<75 years (OR 2.65, 95% CI 1.71-4.07, p < 0.001), not using antiplatelet therapy (OR 1.93, 95% CI 1.21-3.08, p = 0.006), low prestroke mRS (OR 4.33, 95% CI 1.89-9.89, p < 0.001), initial NIHSS (OR 0.89, 95% CI 0.86-0.93, p < 0.001), absent cerebral edema (OR 7.83, 95% CI 3.31-18.51, p < 0.001), and mTICI 2b/3 (OR 4.56, 95% CI 2.17-9.59, p < 0.001) were independently associated with good outcome (mRS 0-2).

CONCLUSIONS

Our findings support the idea that IVT before MT does not influence prognosis, in a real-world setting.

Reperfusion therapy in acute ischemic stroke: dawn of a new era?

Following the success of recent endovascular trials, endovascular therapy has emerged as an exciting addition to the arsenal of clinical management of patients with acute ischemic stroke (AIS). In this paper, we present an extensive overview of intravenous and endovascular reperfusion strategies, recent advances in AIS neurointervention, limitations of various treatment paradigms, and provide insights on imaging-guided reperfusion therapies. A roadmap for imaging guided reperfusion treatment workflow in AIS is also proposed. Both systemic thrombolysis and endovascular treatment have been incorporated into the standard of care in stroke therapy. Further research on advanced imaging-based approaches to select appropriate patients, may widen the time-window for patient selection and would contribute immensely to early thrombolytic strategies, better recanalization rates, and improved clinical outcomes.

Distinct predictive role of collateral status on clinical outcome in variant stroke subtypes of acute large arterial occlusion

BACKGROUND AND PURPOSE

Clinical trials have shown that robust collateral flow has a relationship with good clinical outcome; however, different stroke subtypes were lumped together. This study explored the relationship between baseline collaterals and the onset-to-imaging time (OIT) and the correlation between pre-treatment collateral status and clinical outcome amongst different subtypes.

METHOD

Prospectively collected data from consecutive acute ischaemic stroke patients with acute middle cerebral artery occlusion who received reperfusion therapy were reviewed. The regional leptomeningeal score (20 points) was based on the scoring extent of contrast opacification in the six Alberta Stroke Program Early CT Score (ASPECTS) cortical regions (M1-6), parasagittal anterior cerebral artery territory and the basal ganglia by perfusion-derived dynamic four-dimensional computed tomography angiography (4D CTA). Stroke subtype was determined by the TOAST classification criteria. A 3-months modified Rankin Scale score of 0-2 was defined as a good outcome.

RESULTS

The analysis included 158 patients: 30 (19.0%) patients had large artery atherosclerotic stroke (LAA), 87 (55.1%) cardioembolic stroke (CE) and 41 (25.9%) stroke of undetermined etiology. Baseline collateral was negatively correlated with OIT (P = 0.0205) in the CE group after adjusting for female sex, smoking, hyperlipidemia, baseline National Institutes of Health Stroke Scale (NIHSS) and baseline mismatch ratio, but not in the LAA group. Baseline collateral showed a strong relationship with good clinical outcome after adjusting for recanalization, baseline NIHSS, age and female sex (odds ratio 1.120, confidence interval 1.013-1.238, P = 0.027) in all patients and in the CE group (odds ratio 3.223, confidence interval 1.212-8.570, P = 0.019), but not in the LAA patients.

CONCLUSIONS

Based on 4D CTA, sustained good leptomeningeal collaterals may predict good outcome in CE but not in LAA patients. Moreover, the extent of collaterals was associated with OIT in the CE patients, which indicates prompt reperfusion therapy in this group of patients.

A population-based incidence of M2 strokes indicates potential expansion of large vessel occlusions amenable to endovascular therapy

Background

M2 occlusions may result in poor outcomes and potentially benefit from endovascular therapy. Data on the rate of M2 strokes is lacking.

Methodology

Patients with acute ischemic stroke discharged over a period of 3 years from a tertiary level hospital in the ‘stroke belt’ were evaluated for M2 occlusions on baseline vascular imaging. Regional and national incidence was calculated from discharge and multicounty data.

Results

There were 2739 ICD-9 based AIS discharges. M2 occlusions in 116 (4%, 95% CI 3.5% to 5%) patients constituted the second most common occlusion site. The median National Institute of Health Stroke Scale (NIHSS) score was 12 (IQR 5–18). Good outcomes were observed in 43% (95% CI 34% to 53%), poor outcomes in 57% (95% CI 47% to 66%), and death occurred in 27% (95% CI 19% to 37%) of patients. Receiver operating characteristics curves showed the NIHSS to be predictive of outcomes (area under the curve 0.829, 95% CI 0.745 to 0.913, p<0.0001). An NIHSS score ≥9 was the optimal cut-off point for predicting poor outcomes (sensitivity 85.7%, specificity 67.4%). 71 (61%) patients had an NIHSS score ≥9 and 45 (39%) an NIHSS score <9. The rate of good-outcome was 22.6% for NIHSS score ≥9 versus 78.4% for NIHSSscore <9 (OR=0.08, 95% CI 0.03 to 0.21, p<0.0001). Mortality was 42% for NIHSS score ≥9 versus 2.7% for NIHSS score <9 (OR=26, 95% CI 3.3 to 202, p<0.0001). Infarct volume was 57 (±55.7) cm³ for NIHSS score ≥9 versus 30 (±34)cm³ for NIHSS score <9 (p=0.003). IV recombinant tissue plasminogen activator (rtPA) administered in 28 (24%) patients did not affect outcomes. The rate of M2 occlusions was 7 (95% CI 5 to 9)/100 000 people/year (3%, 95% CI 2% to 4%), giving an incidence of 21 176 (95% CI 15 282 to 29 247)/year. Combined with M1, internal carotid artery terminus and basilar artery, this yields a ‘large vessel occlusion (LVO)+M2’ rate of 31 (95% CI 26 to 35)/100 000 people/year and a national incidence of 99 227 (95% CI 84 004 to 112 005) LVO+M2 strokes/year.

Conclusion

M2 occlusions can present with serious neurological deficits and cause significant morbidity and mortality. Patients with M2 occlusions and higher baseline deficits (NIHSS score ≥9) may benefit from endovascular therapy, thus potentially expanding the category of acute ischemic strokes amenable to intervention.

Intravenous thrombolysis before endovascular therapy for large vessel strokes can lead to significantly higher hospital costs without improving outcomes

Background

Limited efficacy of IV recombinant tissue plasminogen activator (rt-PA) for large vessel occlusions (LVO) raises doubts about its utility prior to endovascular therapy.

Purpose

To compare outcomes and hospital costs for anterior circulation LVOs (middle cerebral artery, internal carotid artery terminus (ICA-T)) treated with either primary endovascular therapy alone (EV-Only) or bridging therapy (IV+EV)).

Methods

A single-center retrospective analysis was performed. Clinical and demographic data were collected prospectively and relevant cost data were obtained for each patient in the study.

Results

90 consecutive patients were divided into EV-Only (n=52) and IV+EV (n=38) groups. There was no difference in demographics, stroke severity, or clot distribution. The mean (SD) time to presentation was 5:19 (4:30) hours in the EV-Only group and 1:46 (0:52) hours in the IV+EV group (p<0.0001). Recanalization: EV-Only 35 (67%) versus IV+EV 31 (81.6%) (p=0.12). Favorable outcome: EV-Only 26 (50%) versus IV+EV 22 (58%) (p=0.45). For patients presenting within 4.5 hours (n=64): Recanalization: EV-Only 21/26 (81%) versus IV+EV 31/38 (81.6%) (p=0.93). Favorable outcome: EV-Only 14/26 (54%) versus IV+EV 22/38 (58%) (p=0.75). There was no significant difference in rates of hemorrhage, mortality, home discharge, or length of stay. A stent retriever was used in 67 cases (74.4%), with similar recanalization, outcomes, and number of passes in the EV-Only and IV+EV groups. The mean (SD) total hospital cost was $33 810 (13 505) for the EV-Only group and $40 743 (17 177) for the IV+EV group (p=0.02). The direct cost was $23 034 (8786) for the EV-Only group and $28 711 (11 406) for the IV+EV group (p=0.007). These significantly higher costs persisted for the subgroup presenting in <4.5 hours and the stent retriever subgroup. IV rt-PA administration independently predicted higher hospital costs.

Conclusions

IV rt-PA did not improve recanalization, thrombectomy efficacy, functional outcomes, or length of stay. Combined therapy was associated with significantly higher total and direct hospital costs than endovascular therapy alone.