Is intra-arterial thrombolysis safe after full-dose intravenous recombinant tissue plasminogen activator for acute ischemic stroke?

Fibrinolysis: strategies to enhance the treatment of acute ischemic stroke

Stroke is a major cause of disability worldwide, and is the second leading cause of death after ischemic heart disease. Until recently, tissue-type plasminogen activator (t-PA) was the only treatment for acute ischemic stroke. If administered within 4.5 h of symptom onset, t-PA improves the outcome in stroke patients. Mechanical thrombectomy is now the preferred treatment for patients with acute ischemic stroke resulting from a large-artery occlusion in the anterior circulation. However, the widespread use of mechanical thrombectomy is limited by two factors. First, only ⁓ 10% of patients with acute ischemic stroke have a proximal large-artery occlusion in the anterior circulation and present early enough to undergo mechanical thrombectomy within 6 h; an additional 9-10% of patients presenting within the 6-24-h time window may also qualify for the procedure. Second, not all stroke centers have the resources or expertise to perform mechanical thrombectomy. Nonetheless, patients who present to hospitals where thrombectomy is not an option can receive intravenous t-PA, and those with qualifying anterior circulation strokes can then be transferred to tertiary stroke centers where thrombectomy is available. Therefore, despite the advances afforded by mechanical thrombectomy, there remains a need for treatments that improve the efficacy and safety of thrombolytic therapy. In this review, we discuss: (i) current treatment options for acute ischemic stroke; (ii) the mechanism of action of fibrinolytic agents; and (iii) potential strategies to manipulate the fibrinolytic system to promote endogenous fibrinolysis or to enhance the efficacy of fibrinolytic therapy.

Is Management of Central Retinal Artery Occlusion the Next Frontier in Cerebrovascular Diseases?

Central retinal artery occlusion (CRAO) is a medical emergency that, if not treated, may result in irreversible loss of vision. It continues to be an important cause for acute painless loss of vision. Amaurosis fugax or "transient CRAO" has long been considered an equivalent of transient cerebral ischemic event. Animal models, in addition to data from retrospective and randomized clinical studies, provide valuable insights into the time interval for irreversible retinal ischemia. Subset analyses from 2 large studies of patients with CRAO show benefit from treatment with thrombolysis within 6 hours from symptoms onset. Significant workflow improvements after the intra-arterial therapy trials for acute ischemic stroke have occurred world over in last 5 years. Patients with CRAO are uniquely suited to receive maximum benefits from the changes in workflow for treatment of patient's acute ischemic stroke. Just as in clinical triage of acute ischemic stroke, correct and timely diagnosis of patients with CRAO may help in preventing visual loss. The approach to acute ocular ischemia should mimic that used for acute brain ischemia. Comprehensive stroke centers would be ideal triage centers for these patients in view of availability of multidisciplinary participation from vascular neurology, neuroendovascular surgery, and ophthalmology. Time is Retina!

Drip, Ship, and On-Demand Endovascular Therapy for Acute Ischemic Stroke

BACKGROUND

The "drip and ship" approach can facilitate an early initiation of intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) at community hospitals. New endovascular treatment modalities, such as stent retrieval, have further improved the rate of safe and successful recanalization. We assessed the clinical outcomes of on-demand endovascular therapy in patients with AIS who were transported to a comprehensive stroke center under the "drip and ship" paradigm.

METHODS

This retrospective study evaluated prospectively registered patients with acute large vessel occlusions in the anterior circulation who underwent endovascular recanalization after IVT at our regional comprehensive stroke center between January 2011 and April 2014. Clinical outcomes and neuroradiological findings were compared between patients who received IVT at the center (direct visit, DV) and at a community hospital (drip and ship, DS).

RESULTS

Baseline characteristics such as age, initial National Institutes of Health Stroke Scale (NIHSS) score, and risk factors for stroke were similar, and most patients underwent endovascular therapy with a Solitaire stent (81.9% vs. 89.3% for DV and DS, respectively, P = 0.55). The average initial NIHSS score was 12.15 ± 4.1 (12.06 vs. 12.39 for DV and DS, respectively, P = 0.719). The proportions of long-term favorable outcomes (modified Rankin Scale score ≤ 2 at 90 days) and successful recanalization (Thrombolysis in Cerebral Ischemia score ≥ 2b) were not significantly different (P = 0.828 and 0.158, respectively). The mortality rates and occurrences of symptomatic intracerebral hemorrhage were not significantly different (P = 0.999 and 0.267, respectively).

CONCLUSIONS

The "drip and ship" approach with subsequent endovascular therapy is a feasible treatment concept for patients with acute large vessel occlusion in the anterior circulation that could help improve clinical outcomes in patients with AIS.

Fibrinolytic PLGA nanoparticles for slow clot lysis within abdominal aortic aneurysms attenuate proteolytic loss of vascular elastic matrix

Abdominal aortic aneurysms (AAAs) involve chronic overexpression of proteases in the aortic wall that result in disruption of elastic fibers and consequent loss of vessel elasticity. Nearly 75% of AAAs contain flow-obstructing, fibrin-rich intraluminal thrombi (ILT), which act as a) a bioinert shield, protecting the underlying AAA wall from high hemodynamic stresses, and b) a reservoir of inflammatory cells and proteases that cause matrix breakdown. For these reasons, restoring flow through the aorta lumen and facilitating transmural diffusion of therapeutics from circulation to the AAA wall must be achieved by slow thrombolysis of the ILT to render it porous without rapid breakdown. Intravenously dosed tissue plasminogen activator (tPA) has been shown to rapidly lyse ILTs in acute stroke and myocardial infarctions. For future use in opening up AAA segments, in this study, we investigated the ability of tPA released from poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) to slowly lyse fibrin clots without inducing proteolytic injury and matrix synthesis-inhibitory effects on cultured rat aneurysmal smooth muscle cells (EaRASMCs). Fibrin clot lysis time was greatly extended over that in presence of exogenous tPA. Surface functionalization of NPs with a cationic amphiphile allowed them to bind to anionic fibrin clot, release tPA at a slower rate and to lyse the clot as a front proceeding outwards in unlike the more rapid and homogenous lysis that occurred due to anionic PLGA NPs. Elastic matrix content was decreased in EaRASMC cultures exposed to byproducts of clot lysis with exogenous tPA, but not tPA-NPs, and was likely due to increased proteolytic activity (MMPs, plasmin) in EaRASMC cultures exposed to exogenous tPA-lysed clots. Our results suggest that gradual ILT lysis via slow release of tPA from NPs will be likely beneficial over exogenous tPA delivery in preserving elastic matrix content and attenuating matrilysis in the adjoining AAA wall, in vivo, while rendering the ILT porous to facilitate transmural delivery of endoluminally delivered AAA therapeutics.

Analysis of prognostic factors of endovascular therapy in 59 patients with acute anterior circulation stroke: a retrospective cohort study – observational

INTRODUCTION

Endovascular therapy (ET) is increasingly used for stroke patients out of the time window, based on the multimodal treatment (MMT) it can be used alone or in combination. The purpose of this study was to assess the outcome of intra-arterial thrombolysis (IAT) and MMT for acute anterior circulation ischemic stroke (ACIS), and reveal prognostic factors of ET in the authors' stroke center.

METHODS

A retrospective analysis of the data of 59 patients with ACIS who received ET from 2010 to 2014 in the stroke center was performed. A univariate analysis was conducted to reveal the differences between IAT and MMT, and the distinctions between favorable and unfavorable outcomes, logistic regression analysis was performed to determine the predictors of outcomes.

RESULTS

Thirty-four patients who accepted MMT had a higher baseline National Institutes of Health Stroke Scale score on admission (18.3 ± 4.2) compared with 25 patients who were treated with IAT (12.6 ± 4.3). The MMT group had a higher patent flow (23/34) (thrombolysis in myocardial infarction grade 2-3) compared with the IAT group (10/25). Moreover, the MMT group had a longer time for emergency department (ED) (5.8 ± 1.4) than the IAT group (5.2 ± 0.8). In multivariate analysis, age, time to ED, and NIHSS score at discharge are predictors for poor outcome, whereas perfect recanalization was associated with favorable outcome.

CONCLUSION

MMT might be suitable for patients with a severe admission NIHSS and a higher patency rate than IAT. Vessel recanalization was the only predictor for favorable outcome.

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.

MR CLEAN, a multicenter randomized clinical trial of endovascular treatment for acute ischemic stroke in the Netherlands: study protocol for a randomized controlled trial

BACKGROUND

Endovascular or intra-arterial treatment (IAT) increases the likelihood of recanalization in patients with acute ischemic stroke caused by a proximal intracranial arterial occlusion. However, a beneficial effect of IAT on functional recovery in patients with acute ischemic stroke remains unproven. The aim of this study is to assess the effect of IAT on functional outcome in patients with acute ischemic stroke. Additionally, we aim to assess the safety of IAT, and the effect on recanalization of different mechanical treatment modalities.

METHODS/DESIGN

A multicenter randomized clinical trial with blinded outcome assessment. The active comparison is IAT versus no IAT. IAT may consist of intra-arterial thrombolysis with alteplase or urokinase, mechanical treatment or both. Mechanical treatment refers to retraction, aspiration, sonolysis, or use of a retrievable stent (stent-retriever). Patients with a relevant intracranial proximal arterial occlusion of the anterior circulation, who can be treated within 6 hours after stroke onset, are eligible. Treatment effect will be estimated with ordinal logistic regression (shift analysis); 500 patients will be included in the trial for a power of 80% to detect a shift leading to a decrease in dependency in 10% of treated patients. The primary outcome is the score on the modified Rankin scale at 90 days. Secondary outcomes are the National Institutes of Health stroke scale score at 24 hours, vessel patency at 24 hours, infarct size on day 5, and the occurrence of major bleeding during the first 5 days.

DISCUSSION

If IAT leads to a 10% absolute reduction in poor outcome after stroke, careful implementation of the intervention could save approximately 1% of all new stroke cases from death or disability annually.

TRIAL REGISTRATION

NTR1804 (7 May 2009)/ISRCTN10888758 (24 July 2012).

The Role of Endovascular Therapy in the Treatment of Acute Ischemic Stroke

Of the approximately 795 000 strokes in the United States annually, 87% are ischemic and result in significant morbidity and mortality. Improvements in acute ischemic stroke (AIS) outcomes have been achieved with intravenous thrombolytics (IVT) and intra-arterial thrombolytics vs supportive medical therapy. Given its ease of administration, noninvasiveness, and most validated efficacy, IVT is the standard of care in AIS patients without contraindications to systemic fibrinolysis. However, patients with large-vessel occlusions respond poorly to IVT. Recent trials designed to select this population for randomization to IVT vs IVT with adjunctive endovascular therapy have not shown improvement in clinical outcomes with endovascular therapy. This could be due to the lack of utilization of modern thrombectomy devices such as Penumbra aspiration devices, Solitaire stent-trievers, or Trevo stent-trievers, which have shown the best recanalization results. Continued improvement in the techniques with using these devices as well as randomized controlled trials using them is warranted. This article defines the goals of AIS revascularization, presents the evolution of treatment from the initial use of IVT to modern thrombectomy devices, and discusses current treatment and ongoing AIS trials.

Optimizing prediction scores for poor outcome after intra-arterial therapy in anterior circulation acute ischemic stroke

BACKGROUND AND PURPOSE

Intra-arterial therapy (IAT) promotes recanalization of large artery occlusions in acute ischemic stroke. Despite high recanalization rates, poor clinical outcomes are common. We attempted to optimize a score that combines clinical and imaging variables to more accurately predict poor outcome after IAT in anterior circulation occlusions.

METHODS

Patients with acute ischemic stroke undergoing IAT at University of Texas (UT) Houston for large artery occlusions (middle cerebral artery or internal carotid artery) were reviewed. Independent predictors of poor outcome (modified Rankin Scale, 4-6) were studied. External validation was performed on IAT-treated patients at Emory University.

RESULTS

A total of 163 patients were identified at UT Houston. Independent predictors of poor outcome (P≤0.2) were identified as score variables using sensitivity analysis and logistic regression. Houston Intra-Arterial Therapy 2 (HIAT2) score ranges 0 to 10: age (≤59=0, 60-79=2, ≥80 years=4), glucose (<150=0, ≥150=1), National Institute Health Stroke Scale (≤10=0, 11-20=1, ≥21=2), the Alberta Stroke Program Early CT Score (8-10=0, ≤7=3). Patients with HIAT2≥5 were more likely to have poor outcomes at discharge (odds ratio, 6.43; 95% confidence interval, 2.75-15.02; P<0.001). After adjusting for reperfusion (Thrombolysis in Cerebral Infarction score≥2b) and time from symptom onset to recanalization, HIAT2≥5 remained an independent predictor of poor outcome (odds ratio, 5.88; 95% confidence interval, 1.96-17.64; P=0.02). Results from the cohort of Emory (198 patients) were consistent; patients with HIAT2 score≥5 had 6× greater odds of poor outcome at discharge and at 90 days. HIAT2 outperformed other previously published predictive scores.

CONCLUSIONS

The HIAT2 score, which combines clinical and imaging variables, performed better than all previous scores in predicting poor outcome after IAT for anterior circulation large artery occlusions.

Early Anticipation of Candidacy for Intra-Arterial Reperfusion Therapy Based on Baseline Clinical Stroke Subtypes: Comparison with Multiparametric MRI Taken within 4.5 Hours from Stroke Onset

Background

The decision to proceed with intra-arterial (IA) reperfusion therapy is typically made late in the course of in-hospital treatment for acute ischemic stroke. Early anticipation of candidacy for IA reperfusion therapy based on clinical stroke subtypes would be useful for guiding stroke management. The aim of this study was to investigate the relationship between the clinical Oxfordshire Community Stroke Project (OCSP) classification and MRI results taken within a 4.5-hour time window from stroke onset, with the hypothesis that the persistence of major arterial occlusion and extended ischemic penumbra, key criteria for proceeding with IA reperfusion therapy, would be distinctive between the clinical stroke subtypes.

Methods

A total of 161 patients with acute ischemic stroke in the anterior circulation were included in this study. All patients were treated with intravenous alteplase, and MRI scans were performed following alteplase initiation. Prior to treatment, the patients were categorized, based on the OCSP classification scheme, as having total anterior circulation infarcts (TACI), partial anterior circulation infarcts (PACI), or lacunar infarcts (LACI). The relationship between OCSP subtypes, MRI parameters, and clinical variables was analyzed.

Results

Overall, 40/161 patients (24.8%) were candidates for IA rescue reperfusion. With respect to the classification, 30/69 TACI (43.5%), 6/33 PACI (18.2%), and 4/59 LACI patients (6.8%) were candidates (p < 0.001). Major arterial occlusion was found in 56/161 patients (34.8%), and 46/69 TACI (66.7%), 6/33 PACI (18.2%), and 4/59 LACI patients (6.8%) had a major arterial occlusion (p < 0.001). A perfusion-diffusion mismatch greater than 20% was found in 85/161 patients (52.8%). More specifically, 40/69 TACI (58.0%), 25/33 PACI (75.8%), and 20/59 LACI patients (33.9%) had a perfusion-diffusion mismatch (p < 0.001). However, in terms of the total area of mismatch, 66.0% of patients with ASPECTS_DWI-PWI ≥2 (Alberta Stroke Program Early CT Score) were classified as TACI patients (p < 0.001) and of the patients with ASPECTS_DWI-PWI ≥3, 74.3% were classified as TACI patients (p < 0.001). Relative to candidates for IA rescue reperfusion, the clinical TACI group showed 75.0% sensitivity, 67.8% specificity, a positive predictive value of 43.5%, and a negative predictive value of 89.1%.

Conclusions

In this study, patients classified as having clinical TACI were significantly more likely to be candidates for IA rescue reperfusion. Additionally, they incurred a higher incidence of persistent major arterial occlusion and had a penumbra area that was significantly larger than normal. Therefore, clinical OCSP can be used as an ‘early warning system’ for IA reperfusion candidacy, which can allow for advanced preparation of IA therapy and theoretically shorten treatment time and reduce infarction.

The Basilar Artery International Cooperation Study (BASICS): study protocol for a randomised controlled trial

Background

Despite recent advances in acute stroke treatment, basilar artery occlusion (BAO) is associated with a death or disability rate of close to 70%. Randomised trials have shown the safety and efficacy of intravenous thrombolysis (IVT) given within 4.5 h and have shown promising results of intra-arterial thrombolysis given within 6 h of symptom onset of acute ischaemic stroke, but these results do not directly apply to patients with an acute BAO because only few, if any, of these patients were included in randomised acute stroke trials.

Recently the results of the Basilar Artery International Cooperation Study (BASICS), a prospective registry of patients with acute symptomatic BAO challenged the often-held assumption that intra-arterial treatment (IAT) is superior to IVT. Our observations in the BASICS registry underscore that we continue to lack a proven treatment modality for patients with an acute BAO and that current clinical practice varies widely.

Design

BASICS is a randomised controlled, multicentre, open label, phase III intervention trial with blinded outcome assessment, investigating the efficacy and safety of additional IAT after IVT in patients with BAO. The trial targets to include 750 patients, aged 18 to 85 years, with CT angiography or MR angiography confirmed BAO treated with IVT. Patients will be randomised between additional IAT followed by optimal medical care versus optimal medical care alone. IVT has to be initiated within 4.5 h from estimated time of BAO and IAT within 6 h. The primary outcome parameter will be favourable outcome at day 90 defined as a modified Rankin Scale score of 0–3.

Discussion

The BASICS registry was observational and has all the limitations of a non-randomised study. As the IAT approach becomes increasingly available and frequently utilised an adequately powered randomised controlled phase III trial investigating the added value of this therapy in patients with an acute symptomatic BAO is needed (clinicaltrials.gov: NCT01717755).

Neurointerventional treatment in acute stroke. Whom to treat? (Endovascular treatment for acute stroke: utility of THRIVE score and HIAT score for patient selection)

PURPOSE

Intra-arterial therapy (IAT) is used increasingly as a treatment option for acute stroke caused by central large vessel occlusions. Despite high rates of recanalization, the clinical outcome is highly variable. The authors evaluated the Houston IAT (HIAT) and the totaled health risks in vascular events (THRIVE) score, two predicting scores designed to identify patients likely to benefit from IAT.

METHODS

Fifty-two patients treated at the Stavanger University Hospital with IAT from May 2009 to June 2012 were included in this study. We combined the scores in an additional analysis. We also performed an additional analysis according to high age and evaluated the scores in respect of technical efficacy.

RESULTS

Fifty-two patients were evaluated by the THRIVE score and 51 by the HIAT score. We found a strong correlation between the level of predicted risk and the actual clinical outcome (THRIVE p = 0.002, HIAT p = 0.003). The correlations were limited to patients successfully recanalized and to patients <80 years. By combining the scores additional 14.3 % of the patients could be identified as poor candidates for IAT. Both scores were insufficient to identify patients with a good clinical outcome.

CONCLUSIONS

Both scores showed a strong correlation to poor clinical outcome in patients <80 years. The specificity of the scores could be enhanced by combining them. Both scores were insufficient to identify patients with a good clinical outcome and showed no association to clinical outcome in patients aged ≥80 years.

Endovascular therapy after intravenous t-PA versus t-PA alone for stroke

BACKGROUND

Endovascular therapy is increasingly used after the administration of intravenous tissue plasminogen activator (t-PA) for patients with moderate-to-severe acute ischemic stroke, but whether a combined approach is more effective than intravenous t-PA alone is uncertain.

METHODS

We randomly assigned eligible patients who had received intravenous t-PA within 3 hours after symptom onset to receive additional endovascular therapy or intravenous t-PA alone, in a 2:1 ratio. The primary outcome measure was a modified Rankin scale score of 2 or less (indicating functional independence) at 90 days (scores range from 0 to 6, with higher scores indicating greater disability).

RESULTS

The study was stopped early because of futility after 656 participants had undergone randomization (434 patients to endovascular therapy and 222 to intravenous t-PA alone). The proportion of participants with a modified Rankin score of 2 or less at 90 days did not differ significantly according to treatment (40.8% with endovascular therapy and 38.7% with intravenous t-PA; absolute adjusted difference, 1.5 percentage points; 95% confidence interval [CI], -6.1 to 9.1, with adjustment for the National Institutes of Health Stroke Scale [NIHSS] score [8-19, indicating moderately severe stroke, or ≥20, indicating severe stroke]), nor were there significant differences for the predefined subgroups of patients with an NIHSS score of 20 or higher (6.8 percentage points; 95% CI, -4.4 to 18.1) and those with a score of 19 or lower (-1.0 percentage point; 95% CI, -10.8 to 8.8). Findings in the endovascular-therapy and intravenous t-PA groups were similar for mortality at 90 days (19.1% and 21.6%, respectively; P=0.52) and the proportion of patients with symptomatic intracerebral hemorrhage within 30 hours after initiation of t-PA (6.2% and 5.9%, respectively; P=0.83).

CONCLUSIONS

The trial showed similar safety outcomes and no significant difference in functional independence with endovascular therapy after intravenous t-PA, as compared with intravenous t-PA alone. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT00359424.).

Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

The authors present an overview of the current evidence and management recommendations for evaluation and treatment of adults with acute ischemic stroke. The intended audiences are prehospital care providers, physicians, allied health professionals, and hospital administrators responsible for the care of acute ischemic stroke patients within the first 48 hours from stroke onset. These guidelines supersede the prior 2007 guidelines and 2009 updates.

METHODS

Members of the writing committee were appointed by the American Stroke Association Stroke Council's Scientific Statement Oversight Committee, representing various areas of medical expertise. Strict adherence to the American Heart Association conflict of interest policy was maintained throughout the consensus process. Panel members were assigned topics relevant to their areas of expertise, reviewed the stroke literature with emphasis on publications since the prior guidelines, and drafted recommendations in accordance with the American Heart Association Stroke Council's Level of Evidence grading algorithm.

RESULTS

The goal of these guidelines is to limit the morbidity and mortality associated with stroke. The guidelines support the overarching concept of stroke systems of care and detail aspects of stroke care from patient recognition; emergency medical services activation, transport, and triage; through the initial hours in the emergency department and stroke unit. The guideline discusses early stroke evaluation and general medical care, as well as ischemic stroke, specific interventions such as reperfusion strategies, and general physiological optimization for cerebral resuscitation.

CONCLUSIONS

Because many of the recommendations are based on limited data, additional research on treatment of acute ischemic stroke remains urgently needed.

The clinical and radiographic importance of distinguishing partial from near-complete reperfusion following intra-arterial stroke therapy

BACKGROUND AND PURPOSE

Reperfusion following intra-arterial stroke therapy is associated with improved clinical outcomes. However, the degree of reperfusion needed to achieve successful outcomes is unknown. The purpose of this analysis was to determine whether the degree of reperfusion has an impact on final infarct volumes and clinical outcomes.

MATERIALS AND METHODS

A retrospective analysis identified 88 consecutive patients who underwent intra-arterial therapy for acute anterior circulation stroke. Reperfusion was graded by using the TICI scale into none (TICI 0 or 1), partial (TICI 2a), or near-complete (TICI 2b/3). Baseline characteristics were compared. For each of these groups, we compared discharge disposition and final infarct volumes.

RESULTS

Near-complete, partial, and no reperfusion occurred in 44.3%, 26.1%, and 29.6% of patients, respectively. Baseline characteristics were similar across all 3 groups. The median NIHSS score was 15. Significant differences in discharge disposition were seen, with 41.0% of the TICI 2b/3 group discharged home versus 17.4% of TICI 2a and 7.7% of TICI 0/1. In-hospital mortality was 12.8% for TICI 2b/3 compared with 39.1% for TICI 2a and 34.6% for TICI 0/1. Patients with near-complete reperfusion were significantly more likely to have infarct volumes ≤70 mL (OR = 12.1; 95% CI, 2.7-54.2), compared with patients with partial reperfusion (OR = 2.2; 95% CI, 0.5-9.6).

CONCLUSIONS

Significant differences exist in outcomes and infarct volumes between partial (TICI 2a) and near-complete (TICI 2b/3) reperfusion following intra-arterial stroke therapy. Further trials should separately report these groups to facilitate comparison among treatment paradigms.

Combined full-dose IV and endovascular thrombolysis in acute ischaemic stroke

BACKGROUND

There is an increasing trend to treating proximal vessel occlusions with intravenous-inter-arterial (IV-IA) thrombolysis. The best dose of IV tissue plasminogen activator (tPA) remains undetermined. We compared the combination of full-dose IV recombinant tissue plasminogen activator (rtPA) and IA thrombolytic therapy to IA therapy.

METHODS

Between 2002 and 2009, we reviewed our computed tomographic angiography database for patients who received full-dose intravenous rtPA and endovascular therapy or endovascular therapy alone for acute ischaemic stroke treatment. Details of demographics, risk factors, endovascular procedure, and symptomatic intracranial haemorrhage were noted. Modified Rankin Scale ≤2 at three-months was used as good outcome. Recanalization was defined as Thrombolysis in Myocardial Ischaemia 2-3 flow on angiography.

RESULTS

Among 157 patients, 104 patients received IV-IA treatment and 53 patients underwent direct IA therapy. There was a higher recanalization rate with IV-IA therapy compared with IA alone (71% vs. 60%, P < 0·21) which was driven by early recanalization after IV rtPA. Mortality and independent outcome were comparable between the two groups. Symptomatic intracranial haemorrhage occurred in 8% of patients (12% in the IA group, 7% in the IV-IA group) but was more frequent as the intensity of intervention increased from device alone to thrombolytic drug alone to device plus thrombolytic drug(s). Recanalization was a strong predictor of reduced mortality risk ratio (RR) 0·48 confidence interval95 0·27-0·84) and favourable outcome (RR 2·14 confidence interval95 1·3-3·5).

CONCLUSIONS

Combined IV-IA therapy with full-dose intravenous rtPA was safe and results in good recanalization rates without excess symptomatic intracranial haemorrhage. Testing of full-dose IV tPA followed by endovascular treatment in the IMS3 trial is justified.

Recanalization of large intracranial vessels using the penumbra system: a single-center experience

BACKGROUND AND PURPOSE

The PS is an innovative mechanical device designed to recanalize large-vessel occlusions by thrombus aspiration. The purpose of this study was to evaluate the effectiveness and neurologic outcome of patients treated with the PS in the setting of acute ischemic stroke.

MATERIALS AND METHODS

A total of 91 patients with acute ischemic stroke due to large-vessel occlusion were treated with the PS and were included in our retrospective study. In 14 patients, only the PS was used for treatment; in 77 patients, mechanical recanalization was combined with IA and/or IV thrombolysis. Outcome was measured by using the mRS; recanalization was assessed with the TICI score.

RESULTS

Mean patient age was 62 ± 19.4 years; the average NIHSS score at hospital admission was 17. Successful recanalization was achieved in 77% of patients. Median time from arterial puncture to recanalization was 49 minutes (quartiles, 31-86 minutes). At follow-up, 36% of the patients showed an NIHSS improvement of ≥10%, and 34% of the patients with an anterior circulation occlusion had an mRS score of ≤2, whereas only 7% of the patients with a posterior occlusion had a favorable outcome at follow-up. In total, 20 patients died during hospitalization; none of these deaths were device-related.

CONCLUSIONS

In this study, the PS was an effective device for mechanical recanalization. Successful recanalization with the PS was associated with significant improvement of functional outcome in patients experiencing ischemic stroke secondary to anterior circulation occlusions.

Bridging therapy in acute ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Pending the results of randomized controlled trials, the benefit and safety of bridging therapy (combined intravenous and intra-arterial thrombolysis) remain to be determined. The aim of this analysis was to give reliable estimates of efficacy and safety outcomes of bridging therapy.

METHODS

We conducted a systematic review of all studies using bridging therapy published between January 1966 and March 2011.

RESULTS

The literature search identified 15 studies. The pooled estimate for recanalization rate was 69.6% (95% CI, 63.9%-75.0%). Meta-analysis on clinical outcomes showed a pooled estimate of 48.9% (95% CI, 42.9%-54.9%) for favorable outcome, 17.9% (95% CI, 12.7%-23.7%) for mortality, and 8.6% (95% CI, 6.8%-10.6%) for symptomatic intracranial hemorrhage. In meta-regression analysis, the shorter mean time to intravenous treatment, the greater the recanalization rate (per 10-minute decrease: OR, 1.24; 95% CI, 1.02-1.51) and the lower mortality rate (per 10-minute decrease: OR, 0.75; 95% CI, 0.60-0.94). By using the control groups of intravenous alteplase-treated patients in 8 studies, bridging therapy was associated with a favorable outcome (OR, 2.26; 95% CI, 1.16-4.40), but no differences in mortality or symptomatic intracranial hemorrhage outcomes were found.

CONCLUSIONS

Bridging therapy is associated with acceptable safety and efficacy in stroke patients. Time to intravenous treatment is critical to improve recanalization rates and favorable outcomes.

Systematic review of outcome after ischemic stroke due to anterior circulation occlusion treated with intravenous, intra-arterial, or combined intravenous+intra-arterial thrombolysis

BACKGROUND AND PURPOSE

The optimal approach to recanalization in acute ischemic stroke is unknown. We performed a literature review and meta-analysis comparing the relative efficacy of 6 reperfusion strategies: (1) 0.9 mg/kg intravenous tissue-type plasminogen activator; (2) intra-arterial chemical thrombolysis; (3) intra-arterial mechanical thrombolysis; (4) intra-arterial combined chemical/mechanical thrombolysis; (5) 0.6 mg/kg intravenous tissue-type plasminogen activator and intra-arterial thrombolysis; and (6) 0.9 mg/kg intravenous tissue-type plasminogen activator and intra-arterial thrombolysis.

METHODS

A literature search in Medline, Embase, and the Cochrane database identified case series, observational studies, and treatment arms of randomized trials of anterior circulation arterial occlusion treated with thrombolytic therapy. Included studies had ≥10 subjects, mean time to treatment <6 hours, and treatment specific reporting of disability, death, and intracerebral hemorrhage. Multivariable metaregression evaluated the effects of treatment group on outcome at the same time as accounting for differences in baseline covariates.

RESULTS

A total of 2986 abstracts were identified from which 54 studies (5019 subjects) were included. There were significant differences across groups in age (P=0.0008), baseline National Institutes of Health Stroke Scale (P=0.0002), and time to treatment initiation (P<0.0001). There were also differences in mean modified Rankin Scale (P<0.0001), mortality (P=0.0024), and symptomatic intracerebral hemorrhage (P=0.0305). Differences in modified Rankin Scale were not significant in the metaregression and likely attributable to differences in baseline covariates between studies.

CONCLUSIONS

This study found no evidence that one reperfusion strategy is superior with respect to efficacy or safety, supporting clinical equipoise between reperfusion strategies. Intravenous tissue-type plasminogen activator remains the standard of care for acute ischemic stroke. Randomized clinical trials are necessary to determine the efficacy of alternative reperfusion strategies. Participation in such trials is strongly recommended.

Efficacy and limitations of multimodal endovascular revascularization other than clot retrieval for acute stroke caused by large-vessel occlusion

BACKGROUND

The purpose of this study was to evaluate the efficacy of multimodal endovascular treatment (EVT) other than clot retrieval for acute large-vessel occlusion (LVO).

METHODS

Fifty-six consecutive patients with a median National Institutes of Health Stroke Scale (NIHSS) score of 15 were included this study. In all cases, intravenous administration of recombinant tissue plasminogen activator had failed (n = 23) or was contraindicated (n = 33). The modes of EVT performed included intra-arterial thrombolysis, mechanical clot disruption including balloon angioplasty, and stent placement. We retrospectively analyzed the treatment efficacy of these techniques and patient outcome.

RESULTS

Successful reperfusion (Thrombolysis in Cerebral Infarction grade 2B or 3) was achieved in 40 of 56 patients (71.4%), and 26 of 56 patients (46.4%) had a favorable clinical outcome (modified Rankin Scale [mRS] score 0 to 2 at 90 days). Successful reperfusion (odds ratio [OR] 163; P = .003), age (OR 0.83; P = .007), and baseline NIHSS score (OR 0.71; P = .009) were independently associated with favorable clinical outcome by multivariate analysis. Successful reperfusion rates of internal carotid terminus or M1 proximal occlusions were significantly lower than those of other vessel occlusion (47.6% v 85.7%; P = .005). Clinically significant procedure-related complications occurred in 1.8% (1/56), and symptomatic intracerebral hemorrhage (sICH) within 48 hours after EVT was observed in 5.4% (3/56) of patients.

CONCLUSIONS

Multimodal EVT for acute LVO yields a high reperfusion rate with a minimal risk of sICH and contributes to favorable patient outcomes. These techniques should be considered when clot retrieval is unsuitable or ineffective.

Safety of full-dose intravenous recombinant tissue plasminogen activator followed by multimodal endovascular therapy for acute ischemic stroke

BACKGROUND AND PURPOSE

The optimal management of stroke patients who fail treatment with intravenous recombinant tissue plasminogen activator (rt-PA) remains unknown. A study was undertaken to establish whether treatment with a standard intravenous t-PA dose (0.9 mg/kg) followed by multimodal endovascular therapy would have a similar safety profile to reduced dose (0.6 mg/kg) bridging therapy.

METHODS

A retrospective analysis was performed of a prospectively collected database. All patients treated with full-dose t-PA and endovascular therapy were included. The primary safety endpoints included ECASS-III symptomatic intracranial hemorrhage (sICH) and ECASS parenchymal hematomas (PH). Secondary safety endpoints included severe systemic bleeding and 90-day mortality. Clinical efficacy endpoints included rates of recanalization (TICI 2-3), ambulation at hospital discharge and 90-day independent outcomes (mRS 0-2).

RESULTS

106 consecutive patients (mean age 69 ± 17 years; mean baseline NIH Stroke Scale 17.8 ± 4.8; 55% women; occlusion sites: MCA-M1 60.4%; MCA-M2 6.6%; ICA-T 19.8%; tandem cervical ICA+MCA-M1 7.5%; basilar artery 5.7%) were identified over a 10-year period. The sICH rate was 8.5% and the PH-1, PH-2 and subarachnoid hemorrhage rates were 2.8%, 8.5% and 2.8%, respectively. There were two (1.9%) severe groin hematomas. The recanalization rate was 66%. At hospital discharge, 41.4% of the patients were ambulatory. The rate of independent functional outcomes at 90 days was 24%; however, this sample is biased since nearly all deaths were captured but detailed 90-day functional outcomes were missing in 27 patients. The 90-day death rate was 32.4%.

CONCLUSION

Combined treatment with full-dose intravenous rt-PA followed by multimodal endovascular therapy seems to be associated with similar rates of sICH to that of bridging therapy with reduced rt-PA dosage.

Safety evaluation of a recombinant plasmin derivative lacking kringles 2-5 and rt-PA in a rat model of transient ischemic stroke

BACKGROUND

Tissue type plasminogen activator is the only approved thrombolytic agent for the treatment of ischemic stroke. However, it carries the disadvantage of a 10-fold increase in symptomatic and asymptomatic intracranial hemorrhage. A safer thrombolytic agent may improve patient prognosis and increase patient participation in thrombolytic treatment. A novel direct-acting thrombolytic agent, Δ(K2-K5) plasmin, promising an improved safety profile was examined for safety in the snare ligature model of stroke in the rat.

METHODS

Male spontaneously hypertensive rats were subjected to 6 hours middle cerebral artery occlusion followed by 18 hours reflow. Beginning 1 minute before reflow, they were dosed with saline, vehicle, Δ(K2-K5) plasmin (0.15, 0.5, 1.5, and 5 mg/kg) or recombinant tissue-type plasminogen activator (10 and 30 mg/kg) by local intra-arterial infusion lasting 10 to 60 minutes. The rats were assessed for bleeding score, infarct volume, modified Bederson score and general behavioral score. In a parallel study, temporal progression of infarct volume was determined. In an in vitro study, whole blood clots from humans, canines and rats were exposed to Δ(K2-K5). Clot lysis was monitored by absorbance at 280 nm.

RESULTS

The main focus of this study was intracranial hemorrhage safety. Δ(K2-K5) plasmin treatment at the highest dose caused no more intracranial hemorrhage than the lowest dose of recombinant tissue type plasminogen activator, but showed at least a 5-fold superior safety margin. Secondary results include: temporal infarct volume progression shows that the greatest expansion of infarct volume occurs within 2-3 hours of middle cerebral artery occlusion in the spontaneously hypertensive rat. A spike in infarct volume was observed at 6 hours ischemia with reflow. Δ(K2-K5) plasmin tended to reduce infarct volume and improve behavior compared to controls. In vitro data suggests that Δ(K2-K5) plasmin is equally effective at lysing clots from humans, canines and rats.

CONCLUSIONS

The superior intracranial hemorrhage safety profile of the direct-acting thrombolytic Δ(K2-K5) plasmin compared with recombinant tissue type plasminogen activator makes this agent a good candidate for clinical evaluation in the treatment of acute ischemic stroke.

Pharmacological revascularization of acute ischaemic stroke: focus on challenges and novel strategies

The only currently approved treatment for acute ischaemic stroke (AIS) is alteplase, a thrombolytic agent given intravenously (IV) within 4.5 hours of symptom onset, in an attempt to reopen occluded intracerebral arteries. However, no more than 5% of all AIS patients receive IV alteplase, mainly because of too long symptom-onset-to-hospital intervals. Moreover, this strategy is effective for less than half of the patients treated within the therapeutic window. Early recanalization is the most powerful prognostic factor, and novel drugs or therapeutic strategies are primarily aimed at improving alteplase efficacy to rapidly and safely reopen the occluded arteries. Because IV alteplase-resistant thrombi are those with the largest clot burden, responsible for the most devastating brain-tissue infarctions, development of novel approved AIS therapies is an urgent priority. At present, in the absence of controlled trials, no valid recommendations can be made. However, the most promising emerging strategy is a combination of standard or low-dose IV alteplase with an intra-arterial (IA) procedure, including additional endovascular thrombolytic and/or mechanical clot retrieval. Notably, results of open trials using the IA route had relatively disappointing clinical outcomes, despite remarkable arterial recanalization rates. Controlled trials are urgently needed to evaluate strategies including an IA route. In addition, logistic and cost constraints will likely limit their routine use, even in industrialized countries. Combining of another IV drug and IV alteplase is a far less studied option, although much easier to implement. Add-on IV drugs could be an antiplatelet glycoprotein (GP) IIb/IIIa receptor antagonist, a direct thrombin inhibitor or a second thrombolytic agent, e.g. tenecteplase. However, neuroimaging to measure the clot burden and infarction size will probably be necessary to predict IV alteplase failure and the subsequent use of these eventual additional therapies.

Comparison of the Incidence of parenchymal hematoma and poor outcome in patients with carotid terminus occlusion treated with intra-arterial urokinase alone or with combined IV rtPA and intra-arterial urokinase

BACKGROUND AND PURPOSE

Patients with acute CTO generally have a poor prognosis, despite IV or IA thrombolytic treatment. The goal of this study was to analyze the results of patients with CTO who had IA urokinase treatment with or without initial IV rtPA based on a bridging protocol.

MATERIALS AND METHODS

Sixteen consecutive patients with acute ischemic stroke due to CTO who had combined IV and IA or a single IA thrombolytic treatment were enrolled. The baseline characteristics and prognosis were described. The patients who did and did not develop a PH shortly after treatment were compared.

RESULTS

The mean age was 66.4 years, and the median initial NIHSS score was 17. The median dose of IA urokinase was 320,000 U, and recanalization (TICI grade II-III) was achieved in 12 patients (75%). However, 5 patients died and 10 patients had poor prognosis with mRS 5-6 at discharge. Six patients (37.5%) with a PH had a higher NIHSS score 1 day after treatment (26.7 versus 13.6, P = .002), and they had more frequent mortality (66.7% versus 10.0%, P = .018) and worse prognosis (mRS 5-6; 100% versus 40%, P = .016) at discharge than patients without PH.

CONCLUSIONS

Patients with CTO who received IA urokinase treatment based on a bridging protocol had a poor prognosis. The development of PH might affect this outcome.

Intra-Arterial Thrombolysis after Full-Dose Intravenous tPA via the "Drip and Ship" Approach in Patients with Acute Ischemic Stroke: Preliminary Report

According to the "drip and ship" concept, patients who are not responsive to intravenous tissue plasminogen activator (IV-tPA) at a community hospital may be candidates for subsequent intra-arterial (IA) thrombolysis at a comprehensive stroke center. We elucidated the efficacy and safety of combined IV/IA thrombolysis via the drip and ship approach. We retrospectively reviewed patients with acute ischemic stroke who underwent combined IV/IA thrombolysis between March 2006 and June 2009. The patients were divided into two groups (inside hospital IV-tPA vs. outside hospital IV-tPA). We compared the short- and long-term clinical outcome, recanalization rate, intracranial hemorrhage after the procedure, and onset to treatment time between the two groups. A total of 23 patients with inside hospital IV-tPA and 10 patients with outside hospital IV-tPA were included. The mean pre-treatment National Institutes of Health Stroke Scale (NIHSS) scores were 15.8 and 17.5, respectively. Baseline characteristics were not significantly different between the two groups. The NIHSS score at 1 week and favorable outcome rate (modified Rankin Scale ≤2) 3 months after the procedure were not significantly different (p=0.730 and p=0.141, respectively). The rate of recanalization and intracranial hemorrhage were not significantly different (p=0.560 and p=0.730, respectively). The onset to IA thrombolysis time was also not significantly different (222.7 vs. 239.3 minutes, p=0.455). Our results suggest that initiation of IV-tPA in a community hospital with rapid transfer to a comprehensive stroke center for subsequent IA thrombolysis can be a safe and feasible therapeutic option in acute stroke management.

Reperfusion Strategies for Acute Ischemic Stroke

Stroke remains a major cause of morbidity and mortality worldwide. Despite preventive measures, effective management strategies are needed to reduce the morbidity and mortality associated with this devastating condition. While the management of hemorrhagic stroke is mostly limited to supportive care, reperfusion strategies in ischemic stroke have been developed and continue to evolve. Conceptually, the pathophysiology of ischemic stroke is similar to that of acute myocardial infarction and the objective of management is similar (ie, to rapidly restore normal flow to reduce permanent damage). It is, therefore, not surprising that the management of acute ischemic stroke includes intravenous (IV) thrombolysis, the only Food and Drug Administration (FDA)-approved strategy at this point. In addition, there are a myriad of emerging endovascular interventional techniques. We review the current literature and discuss some of the technical aspects of endovascular therapy in the setting of acute ischemic stroke.

A New Therapeutic Strategy for Acute Ischemic Stroke

Background and Purpose—

Intravenous tissue-type plasminogen activator (IV tPA) frequently fails to recanalize proximal middle cerebral artery (MCA-M1) obstructions, preventing favorable outcomes. Only neurointerventional procedures prevail in these cases, but well-equipped centers remain scarce. A new therapeutic strategy consisting of a second IV thrombolysis with low-dose tenecteplase was applied.

Methods—

Consecutive patients with an MCA-M1 occlusion that did not reopen at the end of IV tPA perfusion received IV tenecteplase (0.1 mg/kg). Partial or complete thrombolysis in myocardial infarction recanalization (Thrombolysis In Myocardial Infarction grade 2/3) and intracerebral hemorrhage were assessed by magnetic resonance imaging ≈24 hours later. Clinical outcomes at 3 months were evaluated with the modified Rankin score.

Results—

Among 40 patients with MCA-M1 occlusions who received IV tPA, 13 were treated according to the protocol of sequential combined IV thrombolytics. Baseline National Institutes of Health Stroke Scale score was 15. At a mean of 16.8 hours after IV thrombolysis, the recanalization rate was 100% (2 with Thrombolysis In Myocardial Infarction grade 2, 11 with Thrombolysis In Myocardial Infarction grade 3). Intracerebral hemorrhage occurred in 4 of 13 (31%) patients, with no symptomatic hemorrhage. Good clinical outcomes (modified Rankin score=0/1) were achieved in 9 of 13 (69%) patients. Functional outcomes were very similar to those of 13 patients with early IV-tPA recanalization. Among 4 patients treated as protocol violations, 1 presented with a lack of recanalization and a parenchymal hematoma type 2.

Conclusions—

For patients with MCA-M1 occlusions treated with IV tPA but without early recanalization, a second bolus of IV tenecteplase (0.1 mg/kg) may be a relatively safe, effective, and easy option in carefully selected cases, but additional studies are needed to confirm these findings.

Safety of high doses of urokinase and reteplase for acute ischemic stroke

BACKGROUND AND PURPOSE

ET is considered in selected patients with AIS with persistent arterial occlusion after receiving IVT. Limited data exist on the safety of IA high doses of UK and RT for ET. We investigated any correlation between IA doses of UK or RT and safety outcomes in patients who underwent ET.

MATERIALS AND METHODS

We identified all patients from our stroke registry who received UK or RT for ET from 1998 to 2008. Demographics, baseline National Institutes of Health Stroke Scale scores, recanalization rates, rates of attempted MT, mortality, SICH, and discharge modified Rankin Scale scores were collected.

RESULTS

Of 197 patients; 72 received UK and 125 received RT. More than 90% of patients in both groups had received prior IVT. The median IA dose of UK was 200,000 U (range, 25,000-1,500,000 U) and of RT was 2 mg (range, 1-8 mg). Concurrent MT was attempted in 59.7% of UK-treated patients and 72.0% of RT-treated patients, with SICH rates of 4.2% and 8.0%, respectively. Logistic regression adjusting for prior IVT and MT revealed no correlation between SICH and doses of UK (OR, 1.00; 95% CI, 0.99-1.00; P = .94) or RT (OR, 0.803; 95% CI, 0.48-1.33; P = .39). There was no correlation between mortality and doses of UK (OR, 1.00; 95% CI, 0.99-1.00; P = .51) or RT (OR, 1.048; 95% CI, 0.77-1.42; P = .75).

CONCLUSIONS

High IA doses of UK and RT may be safe when given with or without MT in patients with AIS despite receiving a full dose of intravenous recombinant tissue plasminogen activator. These results need prospective validation.

Simultaneous combined intravenous recombinant tissue plasminogen activator and endovascular therapy for hyperacute middle cerebral artery m1 occlusion

We investigated the efficacy and safety of combined intravenous (IV) recombinant tissue plasminogen activator (rtPA) and simultaneous endovascular therapy (ET) for hyperacute middle cerebral artery (MCA) M1 occlusion. Between October 2005 and April 2007, in the combined group, 22 patients eligible for IV rtPA, who were diagnosed as having MCA M1 occlusion, were treated with IV rtPA and simultaneous ET was initiated as soon as possible. The other patients were treated with IV rtPA alone (IV group A: n = 11). Between May 2007 and November 2008, all patients eligible for IV rtPA, who were diagnosed as having MCA M1 occlusion, underwent thrombolysis by IV rtPA alone (IV group B: n = 24). The improvement of the National Institutes of Health Stroke Scale score at 24 hours was highest in the combined group (10 ± 4.1). In contrast, it was 5.1 ± 4.7 in the IV group A (P = 0.017) and 5.6 ± 5.6 in IV group B (P = 0.006). In the combined group, successful recanalization was observed in 18 of 22 patients with one symptomatic intracranial hemorrhage. The rate of mRS0-2 at three months was highest in the combined group, 36% in the IV group A and 33% in the IV group B (P = 0.008).Simultaneous treatment with IV rtPA and ET improved the clinical outcome of MCA M1 occlusion without a significant increase of adverse effects in our study.

Fibrinolysis and Beyond: Bridging the Gap between Local and Systemic Clot Removal

Recanalization methods in ischemic stroke have been progressively expanded over the past years. In addition the continuous development of specialized mechanical devices for thrombectomy a broad spectrum of new drugs has been tested: Both options, novel drugs as well as new devices, can be employed independently of each other, but in most cases a combination of the two with the standard treatment of intravenous fibrinolysis is applied. Until recently, a large number of case series have been performed to investigate the effects of various drugs and interventions, but only a few trials have been conducted to determine the optimal conditions for combining both procedures. This review surveys the different systemic and endovascular vessel reopening practices and their major bridging techniques.

Outcome in acute stroke with different intra-arterial infusion rate of urokinase on thrombolysis

Intra-arterial infusion of urokinase (UK) has been widely used. However, the optimal infusion rate of the reagent has never been determined. This was investigated in the acute stage of middle cerebral artery (MCA) embolism in the present study. Sprague Dawley male rats (n=43) were randomly divided into sham-operation and five ischemic groups with urokinase administration at different infusion rates or without urokinase administration. Ischemia was induced with MCA embolism. Two hours after embolism, total urokinase (urokinase, 170,000U/kg) was given in groups A,B,C and D (n=8 each) at different rates: 1,000 U (0.03 ml/min) per minute, 4,000U (0.12 ml/min), 10,000U (0.30 ml/min), and 16,000U (0.48 ml/min), respectively. Group E received normal saline at a rate of 0.48 ml/min. The sham-operation group (no embolism) received urokinase at (170,000U/kg, 1.5 ml, 16,000 U/min). During ischemia and thrombolysis, regional cerebral blood flow (CBF) was monitored by laser Doppler flowmetry. The neurological deficits, infarct volumes and mortalities in each group were determined. The CBF in ischemic hemisphere were significantly (p<0.05) decreased after embolism in groups A∼E at similar levels (27.32±8.20% to 34.71±6.84%). After different treatments, in group B 4,000U/min infusion of UK induced the best reperfusion, the least neurological deficits and infarct volume, as well as the least mortality and lowest incidence of hemorrhage. The effect of intra-artery thrombolysis of urokinase was related to the infusion rate. Our study demonstrated an optimal infusion rate at 4,000U/min, suggesting relatively low levels of infusion are better able to improve brain reperfusion and reduce brain injury after stroke.