Randomized Trial of Intraarterial Infusion of Urokinase Within 6 Hours of Middle Cerebral Artery Stroke

SYNTHESIS expansion: design of a nonprofit, pragmatic, randomized, controlled trial on the best fast-track endovascular treatment vs. standard intravenous alteplase for acute ischemic stroke

Rationale Reperfusion in ischemic stroke can be pursued by either systemic intravenous thrombolysis or endovascular treatment. However, systemic intravenous thrombolysis with alteplase within 4·5 h of symptom onset in selected patients is the only medication of proven efficacy. No randomized-controlled trials have so far compared the two modalities. To explore this, after a pilot phase, we started the SYNTHESIS Expansion trial. Aims To determine whether endovascular treatment (i.e., intra-arterial thrombolysis with alteplase - if necessary, associated to or substituted by mechanical clot disruption and/or retrieval) compared with systemic intravenous thrombolysis with alteplase, administered according to European labelling, increases the proportion of independent survivors at three-months. Design SYNTHESIS Expansion is an open-label, multicenter randomized-controlled trial, with blinded follow-up. Eligibility applies to; patients with symptomatic ischemic stroke, seen within 4·5 h of onset; being able to initiate intravenous alteplase immediately, and endovascular treatment as soon as possible (not later than six-hours of stroke onset). The study is pragmatically based on the 'uncertainty principle' between endovascular treatment and systemic intravenous thrombolysis for patients eligible for intravenous alteplase. There are no prespecified clinical or instrumental criteria to further select a patient, although investigators are left free to use them. Enrollment will be completed with 350 randomized patients. Primary analysis is on an intent-to-treat basis. Study outcomes Primary: modified Rankin scale score of 0 or 1 at three-months. Secondary: neurological deficit seven-days after thrombolysis and the safety of the procedure on the basis of events reported within seven-days following thrombolysis - symptomatic cerebral hemorrhage, fatal and nonfatal stroke, death from any cause, neurological deterioration.

Intra-arterial treatment methods in acute stroke therapy

Acute revascularization is associated with improved outcomes in ischemic stroke patients. It is unclear which method of intra-arterial intervention, if any, is ideal. Promising approaches in acute stroke treatment are likely a combination of intravenous and endovascular revascularization efforts, combining early treatment initiation with direct clot manipulation and/or PTA/stenting. In this review, we will discuss available thrombolytic therapies and endovascular recanalization techniques, beginning with chemical thrombolytic agents, followed by mechanical devices, and a review of ongoing trials. Further randomized studies comparing medical therapy, intravenous and endovascular treatments are essential, and their implementation will require the wide support and enthusiasm from the neurologic, neuroradiologic, and neurosurgical stroke communities.

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.

MR imaging-based localized intra-arterial thrombolysis assisted by mechanical clot disruption for acute ischemic stroke due to middle cerebral artery occlusion

BACKGROUND AND PURPOSE

LIT-MCD is used in our institution for acute stroke due to MCA occlusion, with the goal of reducing symptomatic intracranial hemorrhage by maintaining recanalization of the occluded vessels. The purpose of the study was to investigate the safety and efficacy of LIT-MCD and to identify factors associated with a poor outcome in patients undergoing this procedure.

MATERIALS AND METHODS

LIT-MCD for MCA occlusion was performed in 90 of 1907 consecutive patients with acute stroke admitted to our institution. Radiographic data and clinical outcome were evaluated in the 90 patients, and factors predictive of a poor outcome (3-month mRS score, 3-6) were investigated by multivariate analysis.

RESULTS

Recanalization was achieved in 73 of the 90 patients (81%); symptomatic intracranial hemorrhage occurred in 7 (8%); procedure-related complications, in 9 (10%); and a favorable clinical outcome (3-month mRS score, 0-2), in 48 (53%). A high baseline NIHSS score (≥20), a low preprocedural ASPECTS on MR imaging (≤7), proximal M1 occlusion (in the horizontal segment of the MCA at or proximal to the lenticulostriate arteries), and no recanalization were significant predictors of a poor clinical outcome.

CONCLUSIONS

LIT-MCD is a safe and effective treatment for acute stroke due to MCA occlusion. However, further intervention is needed to improve the outcome of patients with proximal M1 occlusion.

Mechanical thrombectomy with the Penumbra recanalization device in acute ischemic stroke

BACKGROUND AND PURPOSE

The aim of this study was to assess the clinical outcome of patients treated with the Penumbra system (PS) for acute ischemic stroke. A retrospective, monocentric matched-pair analysis in comparison with patients treated by intraarterial thrombolysis (IAT) with alteplase was designed for this purpose.

METHODS

Twenty-two consecutive patients, (mean age 62), with acute ischemic stroke and National Institutes of Health Stroke Scale (NIHSS) scores ≥ 7 were treated with the PS. Twenty corresponding patients could be identified, treated with IAT. Matches were sought for initial NIHSS score and target vessels. Thrombolysis in myocardial infarction (TIMI) grades, mortality rates, NIHSS upon discharge, and modified Rankin scores (mRs) at 90 days were compared.

RESULTS

A total of 32 vessels in 20 patients were treated in either arm of the study. Recanalization to TIMI 2/3 was successful in 25/32 (78%) of target vessels with the PS, and 17/32 (53%) of target vessels in the IAT group. Upon discharge, 2/20 patients treated with PS and 7/20 patients treated with IAT had a NIHSS score of 0 to 1 or an improvement greater or equal to 10-point on the NIHSS scale. All cause mortality at 90 days was 3/20 patients treated with PS, and 2/20 patients treated with IAT. Three out of twenty patients treated with PS and 7/20 patients treated with IAT had a mRS of ≤ 2 at 90 days.

CONCLUSION

The Penumbra system is effective in re-opening occluded major arteries. Our data seems to indicate that not all patients benefit clinically from improved revascularization of occluded major arteries.

Meta-analysis of randomized intra-arterial thrombolytic trials for the treatment of acute stroke due to middle cerebral artery occlusion

BACKGROUND

Randomized clinical trials supporting the use of intra-arterial administration of thrombolytics (IAT) for the treatment of stroke due to middle cerebral artery (MCA) occlusion have been positive on some, but not all, endpoints. A meta-analysis was performed to estimate with more precision the effect of IAT on several key clinical endpoints.

METHODS

All randomized trials of IAT in the treatment of MCA stroke were identified by PUBMED search and by hand search of potentially relevant references. Trial methodologies were assessed for compatibility in study protocols and statistical analysis. A meta-analysis was performed evaluating the effect of IAT on functional outcome at 90 days and symptomatic intracranial hemorrhage (SICH) within 24 h.

RESULTS

Three trials met the criteria for the meta-analysis. IAT treated patients were significantly more likely to have a modified Rankin scale (mRS) ≤ 1 (31% vs 20%, OR 2.0, 95% CI 1.2 to 3.4, p=0.01); mRS ≤ 2 (43% vs 31%, OR 1.9, 95% CI 1.2 to 3.0, p=0.01); and NIH Stroke Scale score 0 or 1 (23% vs 12%, OR 2.4, 95% CI 1.3 to 4.4, p=0.007) at the 90 day follow-up. There was no effect on mortality at 90 days (20% vs 19%, OR 0.84, 95% CI 0.5 to 1.5). The risk of SICH was significantly increased in the active treatment arms (11% vs 2%, OR 4.6, 95% CI 1.3 to 16, p=0.02).

CONCLUSIONS

Our meta-analysis demonstrates that all standard functional endpoints for stroke trials were substantially improved in the active treatment arms. Despite an increased risk of SICH, there was no effect on mortality. These results support endovascular treatment of acute ischemic stroke due to MCA occlusion with intra-arterial thrombolytics.

A Combined Treatment with Taurine and Intra-arterial Thrombolysis in an Embolic Model of Stroke in Rats: Increased Neuroprotective Efficacy and Extended Therapeutic Time Window

Combination treatment may target different pathophysiological events following cerebral ischemia thus enhancing the efficacy of treatment in thromboembolic stroke. Taurine confers a neuroprotective effect in the mechanical stroke model. This effect has not been assessed in an embolic stroke model. Here, we sought to evaluate the neuroprotective effect of taurine alone and in combination with thrombolytic therapy to investigate whether combined administration would extend the therapeutic time window without increasing the hemorrhagic transformation in a rat embolic stroke model. Rats were subjected to right embolic middle cerebral artery occlusion and then randomly assigned to the following groups: saline treatment alone at 4 h, urokinase, taurine treatment alone at 4, 6, or 8 h, and the combination of taurine and urokinase at 4, 6, or 8 h after the insult. Brain infarct volume, neurobehavioral outcome, regional cerebral blood flow, intracranial hemorrhage incidence were observed and evaluated. Posttreatment with taurine at 4 or 6 h, urokinase at 4 h or in combination at 4, 6, or 8 h significantly reduced infarct volume and improved neurobehavioral outcome. The combination treatment had better neurobehavioral outcome and smaller infarction volume than urokinase or taurine treatment alone. The clinical outcome correlated well with infarct volume. Together, the present study suggests that administration of taurine after stroke is neuroprotective, seemingly because it reduces the reperfusion damage of urokinase, leading to widen the therapeutic window for the thrombolytic effect of urokinase to 8 h. Thrombolysis can also enhance the neuroprotective effect of taurine. The reduction of inflammatory response, neuron death and inhibition of blood brain barrier (BBB) disruption may underlie the beneficial effects of combination of taurine and urokinase in the treatment of embolic stroke.

Thrombolysis for cerebral ischemia

The care for patients with acute ischemic stroke has been revolutionized by the clinical application of fibrinolysis. Intravenous recombinant tissue plasminogen activator (rt-PA) has been proven to improve functional outcomes following acute ischemic stroke and can be administered to a select group of patients up to 4.5 h after symptom onset. Time from symptom onset to thrombolysis is the most important determinant of the success of treatment, with greatest efficacy if given within 90 min. Hospitals should implement standardized processes and protocols for acute stroke to guide immediate patient assessment, brain imaging, drug administration, and post-thrombolysis care. In this article we review the clinical application of thrombolysis, care of acute stroke patients, current evidence regarding fibrinolysis, and future direction of penumbral imaging to select candidates for reperfusion therapies.

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.

Acute ischemic stroke treatment: State of the art

Stroke is among the leading causes of death and serious disability in the United States. Treatment of the acute ischemic stroke patient requires a multidisciplinary approach involving first-responders, emergency department personnel, neurologists, advanced imaging experts and endovascular specialists with neurosurgical support. Contemporary stroke treatment is a rapidly advancing field. New developments in pharmacologic and endovascular stroke therapy require thoughtful trial design and expeditious trial implementation to assess clinical outcomes. This manuscript reviews the state of the art in acute stroke therapy.

Percutaneous vascular interventions for acute ischaemic stroke

BACKGROUND

Most disabling strokes are due to blockage of a large artery in the brain by a blood clot. Prompt removal of the clot with intra-arterial thrombolytic drugs or mechanical devices, or both, can restore blood flow before major brain damage has occurred, leading to improved recovery. However, these so-called percutaneous vascular interventions can cause bleeding in the brain.

OBJECTIVES

To assess the safety and efficacy of percutaneous vascular interventions in patients with acute ischaemic stroke.

SEARCH STRATEGY

We searched the Trials Registers of the Cochrane Stroke Group and Cochrane Peripheral Vascular Diseases Group (last searched May 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 5), MEDLINE (1980 to May 2010), EMBASE (1980 to May 2010) and eight additional databases. We also searched trials registers, screened reference lists, contacted researchers and equipment manufacturers, and handsearched journals and conference proceedings.

SELECTION CRITERIA

Randomised, controlled and unconfounded trials of any percutaneous vascular intervention compared with control in patients with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria, extracted data and assessed trial quality. We obtained both published and unpublished data if available

MAIN RESULTS

We included four trials involving 350 patients. Not all trials contributed data to each outcome. The trials tested either intra-arterial urokinase or recombinant pro-urokinase versus an open control. One trial used guidewire-mediated clot disruption in some patients randomised to the intervention group. Most data came from trials that started treatment up to six hours after stroke; one small trial started treatment up to a median of 12.5 hours after stroke. Most data came from trials of middle cerebral artery territory infarction. Compared with non-thrombolytic standard medical treatment, the intervention administered up to six hours after ischaemic stroke significantly increased the proportion of patients with favourable outcome (modified Rankin 0 to 2) three months after stroke (relative risk (RR) 1.47, 95% confidence interval (CI) 1.07 to 2.02). The intervention also significantly increased the risk of symptomatic intracranial haemorrhage within 24 hours of treatment (RR 3.85, 95% CI 0.91 to 16.36). There was no significant heterogeneity between the included trials.

AUTHORS' CONCLUSIONS

Overall, intervention results in a significant increase in the proportion of patients with a favourable outcome, despite a significant increase in intracranial haemorrhage. Further trials are needed to confirm or refute these findings and, given the cost and practical difficulties, to establish whether percutaneous techniques are feasible and cost effective in wider clinical practice.

The pattern of leptomeningeal collaterals on CT angiography is a strong predictor of long-term functional outcome in stroke patients with large vessel intracranial occlusion

BACKGROUND AND PURPOSE

The role of noninvasive methods in the evaluation of collateral circulation has yet to be defined. We hypothesized that a favorable pattern of leptomeningeal collaterals, as identified by CT angiography, correlates with improved outcomes.

METHODS

Data from a prospective cohort study at 2 university-based hospitals where CT angiography was systematically performed in the acute phase of ischemic stroke were analyzed. Patients with complete occlusion of the intracranial internal carotid artery and/or the middle cerebral artery (M1 or M2 segments) were selected. The leptomeningeal collateral pattern was graded as a 3-category ordinal variable (less, equal, or greater than the unaffected contralateral hemisphere). Univariate and multivariate analyses were performed to define the independent predictors of good outcome at 6 months (modified Rankin Scale score ≤2).

RESULTS

One hundred ninety-six patients were selected. The mean age was 69±17 years and the median National Institute of Health Stroke Scale score was 13 (interquartile range, 6 to 17). In the univariate analysis, age, baseline National Institute of Health Stroke Scale score, prestroke modified Rankin Scale score, Alberta Stroke Programme Early CT score, admission blood glucose, history of hypertension, coronary artery disease, congestive heart failure, atrial fibrillation, site of occlusion, and collateral pattern were predictors of outcome. In the multivariate analysis, age (OR, 0.95; 95% CI, 0.93 to 0.98; P=0.001), baseline National Institute of Health Stroke Scale (OR, 0.75; 0.69 to 0.83; P<0.001), prestroke modified Rankin Scale score (OR, 0.41; 0.22 to 0.76; P=0.01), intravenous recombinant tissue plasminogen activator (OR, 4.92; 1.83 to 13.25; P=0.01), diabetes (OR, 0.31; 0.01 to 0.98; P=0.046), and leptomeningeal collaterals (OR, 1.93; 1.06 to 3.34; P=0.03) were identified as independent predictors of good outcome.

CONCLUSIONS

Consistent with angiographic studies, leptomeningeal collaterals on CT angiography are also a reliable marker of good outcome in ischemic stroke.

Intravenous rt-PA versus endovascular therapy for acute ischemic stroke

The influence of baseline stroke severity on outcome makes comparisons between nonrandomized studies of intravenous and intra-arterial (IA) therapy problematic. Using pooled data from the placebo arms of randomized trials in acute ischemic stroke, we derived predictive functions for outcome. We then compared the outcomes from published trials to these functions. Net benefit was calculated by comparison of the individual study with the predicted outcome based on the therapeutic time window. Similar net benefit for IA therapy and intravenous therapy was found at 3 hours and 6 hours; a slight advantage for IA therapy was mitigated by an increase in mortality at 6 hours and by publication bias. No net benefit for IA therapy was shown in the time window greater than 6 hours. Conclusive evidence for the superiority of either therapy awaits prospective randomized trials.

Current recommendations for endovascular interventions in the treatment of ischemic stroke

Ischemic stroke remains one of the leading cause of adult death and disability in the United States. Reperfusion of the occluded vessel is the standard of care in the setting of acute ischemic stroke according to established guidelines. Since the introduction of intravenous (IV) recombinant tissue plasminogen activator (rt-PA) in the late 1990s, significant advances have been made in methods to deliver thrombolytic agents and in devices for mechanical recanalization of occluded vessels. Furthermore, improvements in patient selection contribute to achievement of good clinical outcomes after endovascular therapy. This article summarizes findings from recent clinical trials and presents evidence-based guidelines for endovascular interventions in the treatment of ischemic stroke.

Percutaneous balloon angioplasty for acute occlusion of intracranial arteries

BACKGROUND

The benefits of intravenous thrombolysis for acute ischemic stroke are still limited.

OBJECTIVE

To evaluate the safety and efficacy of double-lumen balloon catheter-based reperfusion therapy with or without intra-arterial thrombolysis for acute occlusion of intracranial arteries.

METHODS

Fifty-nine patients with acute occlusion of intracranial arteries were enrolled. A Gateway balloon catheter was used to disrupt clots or dilate atheromatous plaques in every patient. The technical details, technique-related complications, recanalization rates, and clinical outcomes were analyzed.

RESULTS

The occlusion sites were internal carotid arteries in 17 patients, M1 segments in 32 patients, the M2 segment in 1 patient, a vertebral artery in 1 patient, and basilar arteries in 8 patients. Twenty-four patients (41%) were treated with thrombolysis first, and 20 patients (34%) were treated with percutaneous transluminal angioplasty (PTA) followed by thrombolysis. PTA alone was performed in 15 patients (25%). The mean dose of urokinase was 205 x 10 U. The extent of recanalization was complete (Thrombolysis in Myocardial Infarction [TIMI] score of 3) in 17 patients (29%), and partial (TIMI 1/2) in 28 patients (47%). Functional independence at discharge was preserved in 76%, 25%, and 7% of patients with TIMI 3, TIMI 1/2, and TIMI 0, respectively. A combination of PTA and thrombolysis resulted in a significantly higher recanalization rate than PTA only. Seven patients (12%) experienced hemorrhagic events after treatment. Severe parenchymal hemorrhage with neurologic deterioration was observed in 2 patients (4%), and vessel rupture was encountered in 1 atherosclerotic case.

CONCLUSIONS

Mechanical angioplasty using a Gateway catheter combined with a low-dose thrombolytic agent is a safe and effective treatment for acute intracranial embolic and atherosclerotic occlusion with a low risk of hemorrhagic complications.

Intra-arterial versus intra-venous thrombolysis within and after the first 3 hours of stroke onset

The NINDS trial demonstrated for the first time the effectiveness of intravenous thrombolysis in improving outcome after acute ischemic stroke. The absolute benefit of this intervention was 11-13% greater chance of being normal or near normal (MRS ≤ 1) at 3 months. However, if patients with severe stroke were considered (NIHSS ≥ 20), the absolute benefit dropped to 5-6%, indicating that IV thrombolysis may not be as effective for large vessel occlusion. This observation was further supported by TCD studies that clearly demonstrated that large artery occlusions had a recanalization rate of 13-18% with IV rt-PA. Intra-arterial thrombolysis achieves recanalization rates of 60-70%. Since tissue viability is clearly important, it is time to stop defining rigid time windows and if there is a large penumbra (20-50%) and the occlusion is in a large artery, there exists a logic and a growing evidence to consider either bridge therapy or direct intra-arterial therapy.

Current endovascular treatment of acute stroke and future aspects

Acute ischemic stroke remains a condition of high morbidity and mortality. Until now, the only established therapy has been intravenous (IV) tissue-type plasminogen activator (tPA). Only 3-10% of patients with acute ischemic stroke receive this treatment. On the basis of data from part 3 of the European Collaborative Acute Stroke Study (ECASS III), the time window for beneficial treatment of ischemic stroke with IV tPA has been extended from 3 to 4.5h after the onset of stroke symptoms. Beyond that window of opportunity, and additionally to IV treatment, interventional stroke therapy has assumed an important role for the treatment of acute ischemic stroke. Currently, new promising pharmacological and mechanical treatment options are being established as routine procedures to achieve a further improved outcome for stroke patients.

Efficacy of Intra-Arterial Fibrinolysis for Acute Ischemic Stroke

Background and Purpose— Although intra-arterial (IA) fibrinolysis for acute ischemic stroke has been clinically available for many years, it is not a therapy approved by the US Food and Drug Administration. Single, randomized, clinical trials (RCTs) have suggested beneficial effects, but no single RCT has demonstrated that IA fibrinolysis yields increases in both good (modified Rankin Scale score 0 to 2) and excellent (modified Rankin Scale score 0 to 1) outcomes when compared with the control group. Relatively few participants and inadequate statistical power in single RCTs may have contributed to this difficulty.

Method— We performed a systematic literature search to identified RCTs of IA fibrinolysis in acute ischemic stroke. Multiple outcomes were analyzed, with emphasis on good and excellent outcomes at 90 days or at trial end point.

Results— The systematic search identified 5 RCTs with 395 participants comparing IA fibrinolysis and control. IA fibrinolysis was associated with increased good (odds ratio=2.05; 95% CI, 1.33 to 3.14; P =0.001) and excellent (odds ratio=2.14; 95% CI, 1.31 to 3.51; P =0.003) outcomes. For additional end points, IA fibrinolysis was associated with increased frequencies of minimal neurologic deficit (National Institutes of Health Stroke Scale score 0 to 1), minimal impairment of activities of daily living (Barthel Index 90 to 100 or 95 to 100), and recanalization. IA fibrinolysis was associated with increased radiological and symptomatic intracerebral hemorrhage. However, there was no difference in mortality between groups.

Conclusions— Formal meta-analysis suggests that IA fibrinolysis substantially increases recanalization rates and good and excellent clinical outcomes in acute ischemic stroke. Increased hemorrhage frequencies are not associated with any increase in mortality.

Clinical Outcomes in Middle Cerebral Artery Trunk Occlusions Versus Secondary Division Occlusions After Mechanical Thrombectomy

Background and Purpose— The benefit of endovascular revascularization of patients with acute ischemic stroke with middle cerebral artery (MCA) secondary division (M2) occlusions as compared with MCA trunk (M1) occlusions is not known. In this analysis, we compared revascularization status and clinical outcomes in patients with angiographically confirmed MCA M1 versus isolated M2 occlusions treated with mechanical thrombectomy using the Merci Retriever devices.

Methods— We retrospectively analyzed the pooled data of patients with MCA strokes from the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI trials. Patient data were dichotomized into 2 groups: MCA M1 occlusions and isolated M2 occlusions. Baseline characteristics, revascularization rates, hemorrhage rates, complications, outcomes, and mortality were evaluated for both groups.

Results— Of 178 patients with MCA occlusion treated in the MERCI and Multi MERCI trials, 84.3% had M1 lesions and 15.7% had isolated M2 lesions. Patients with isolated M2 occlusions were revascularized at a higher rate, required a lower mean number of passes, and were associated with a trend toward shorter mean procedure time than patients with M1 occlusions. No statistically significant differences were found between M2 and M1 groups for symptomatic hemorrhage, clinically significant procedural adverse events, favorable 90-day outcome, or 90-day mortality, although in all instances, the M2 outcomes were numerically better than those in M1 subjects. In multivariate analysis, final revascularization was the strongest independent predictor of good outcome at 90 days.

Conclusions— Patients with both MCA M1 occlusions and isolated M2 occlusions can achieve a relatively high rate of revascularization and favorable clinical outcomes after mechanical thrombectomy. In fact, patients with isolated M2 occlusions had a higher rate of revascularization, required fewer passes, and had no increased complications compared with patients with M1 occlusions.

Brain salvage for cardiac cerebral embolism following myocardial infarction

Acute ischemic stroke due to thromboembolism from the left ventricle is a serious complication following myocardial infarction (MI). Despite the attention given to acute stroke intervention, peri-MI ischemic stroke is an underappreciated condition. Here, we describe a case of acute cardiac thromboembolic occlusion of the middle cerebral artery with preceding MI in which brain salvage was achieved by balloon angioplasty.

The molecular basis of thrombolysis and its clinical application in stroke

The rationale for thrombolysis, the most promising pharmacological approach in acute ischaemic stroke, is centred on the principal cause of most ischaemic strokes: the thrombus that occludes the cerebral artery, and renders part of the brain ischaemic. The occluding thrombus is bound together within fibrin. Fibrinolysis acts by activation of plasminogen to plasmin; plasmin splits fibrinogen and fibrin and lyses the clot, which then allows reperfusion of the ischaemic brain. Thrombolytic agents include streptokinase (SK) and recombinant tissue-type plasminogen activator (rt-PA) amongst others under test or development. SK is nonfibrin-specific, has a longer half-life than tissue-type plasminogen activator (t-PA), prevents re-occlusion and is degraded enzymatically in the circulation. rt-PA is more fibrin-specific and clot-dissolving, and is metabolized during the first passage in the liver. In animal models of ischaemic stroke, the effects of rt-PA are remarkably consistent with the effects seen in human clinical trials. For clinical application, some outcome data from the Cochrane Database of Systematic Reviews which includes all randomized evidence available on thrombolysis in man were used. Trials included tested urokinase, SK, rt-PA, pro-urokinase, or desmoteplase. The chief immediate hazard of thrombolytic therapy is fatal intracranial bleeding. However, despite the risk, the human trial data suggest the immediate hazards and the apparent substantial scope for net benefit of thrombolytic therapy given up to 6 h of acute ischaemic stroke. So far the fibrin-specific rt-PA is the only agent to be approved for use in stroke. This may be due to its short half-life and its absence of any specific amount of circulating fibrinogen degradation products, thereby leaving platelet function intact. The short half-life does not leave rt-PA without danger for haemorrhage after the infusion. Due to its fibrin-specificity, it can persist within a fibrin-rich clot for one or more days. The molecular mechanisms with regards to fibrin-specificity in thrombolytic agents should, if further studied, be addressed in within-trial comparisons. rt-PA has antigenic properties and although their long-term clinical relevance is unclear there should be surveillance for allergic reactions in relation to treatment. Although rt-PA is approved for use in selected patients, there is scope for benefit in a much wider variety of patients. A number of trials are underway to assess which additional patients - beyond the age and time limits of the current approval - might benefit, and how best to identify them.

Neuroendovascular management of acute ischemic stroke

Endovascular reperfusion therapy is evolving as a promising treatment in the setting of acute ischemic stroke. Careful patient selection and angiographic evaluation of the location and extent of occlusion are necessary for the successful management of stroke patients. Intra-arterial chemical thrombolysis, with such agents as alteplase and urokinase, has shown favorable results in the early management of cerebrovascular ischemia. Mechanical thrombolysis is becoming an adjunctive or alternative treatment therapy via novel clot dissolution and retrieval techniques. Existing and upcoming trials are investigating the safety and efficacy of neuroendovascular therapy while attempting to expand its indications in acute ischemic stroke.

Effects of 0.6 mg/kg intravenous alteplase on vascular and clinical outcomes in middle cerebral artery occlusion: Japan Alteplase Clinical Trial II (J-ACT II)

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate further the efficacy of 0.6 mg/kg intravenous alteplase on vascular and clinical outcomes in patients with middle cerebral artery occlusion in a postmarketing Phase IV trial of prospective cohort study design.

METHODS

Alteplase was given intravenously at 0.6 mg/kg to patients with ischemic stroke within 3 hours of onset with MR angiography-documented middle cerebral artery occlusion. Vascular outcome was evaluated by MR angiography at 6 and 24 hours after symptom onset based on the modified Mori grade. The primary end points also included a favorable outcome (modified Rankin Scale 0 to 1 at 3 months after onset) and incidence of symptomatic intracranial hemorrhage within 36 hours after treatment. The impact of recanalization on clinical outcome was assessed by stepwise logistic regression analysis.

RESULTS

Fifty-eight patients were enrolled. Recanalization was noted in 51.7% on 6-hour MR angiography and 69.0% on 24-hour MR angiography. A favorable clinical outcome was achieved in 46.6%. None had symptomatic intracranial hemorrhage. In logistic regression models, recanalization on either 6-hour or 24-hour MR angiography was an independent predictor for clinical outcome as well as the baseline National Institutes of Health Stroke Scale score.

CONCLUSIONS

Early recanalization of an occluded middle cerebral artery can be provoked by 0.6 mg/kg intravenous alteplase and may induce a favorable clinical outcome. The rates of recanalization and favorable outcome are comparable to that previously reported with the 0.9-mg/kg dose.

Management of spontaneous dissection of the cervical carotid artery

This manuscript reviews the management of patients with spontaneous dissection of the cervical internal carotid artery (sICAD). Recommendations are not based on controlled-randomized trials, but on case-control and observational, hospital-based studies, and case reports. Vascular risk factors seem to be as prevalent in patients with sICAD as in age-matched, healthy volunteers. Stroke prevention includes the treatment of vascular risk factors and the administration of oral aspirin, which may be as effective as anticoagulation. The few available data indicate that most patients with sICAD causing severe stenosis or occlusion, or an aneurysm can be treated conservatively. Patients with sICAD were not excluded in the intravenous controlled-randomized thrombolysis trials with tissue plasminogen activator, but were excluded in the intraarterial controlled-randomized thrombolysis trials. Taking the few published case series and reports on thrombolysis in patients with sICAD into consideration, intravenous thrombolysis may be beneficial, whereas it remains unclear whether intraarterial thrombolysis is useful.

Thrombolysis for acute ischaemic stroke

BACKGROUND

The majority of strokes are due to blockage of an artery in the brain by a blood clot. Prompt treatment with thrombolytic drugs can restore blood flow before major brain damage has occurred and could improve recovery after stroke. Thrombolytic drugs, however, can also cause serious bleeding in the brain, which can be fatal. One drug, recombinant tissue plasminogen activator (rt-PA), is licensed for use in highly selected patients within three hours of stroke.

OBJECTIVES

To assess the safety and efficacy of thrombolytic agents in patients with acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched October 2008), MEDLINE (1966 to October 2008) and EMBASE (1980 to October 2008). We contacted researchers and pharmaceutical companies, attended relevant conferences and handsearched pertinent journals.

SELECTION CRITERIA

Randomised trials of any thrombolytic agent compared with control in patients with definite ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria and extracted data. We assessed trial quality. We verified the extracted data with the principal investigators of all major trials. We obtained both published and unpublished data if available.

MAIN RESULTS

We included 26 trials involving 7152 patients. Not all trials contributed data to each outcome. The trials tested urokinase, streptokinase, recombinant tissue plasminogen activator, recombinant pro-urokinase or desmoteplase. Four trials used intra-arterial administration, the rest used the intravenous route. Most data come from trials that started treatment up to six hours after stroke; three trials started treatment up to nine hours and one small trial up to 24 hours after stroke. About 55% of the data (patients and trials) come from trials testing intravenous tissue plasminogen activator. Very few of the patients (0.5%) were aged over 80 years. Many trials had some imbalances in key prognostic variables. Several trials did not have complete blinding of outcome assessment. Thrombolytic therapy, mostly administered up to six hours after ischaemic stroke, significantly reduced the proportion of patients who were dead or dependent (modified Rankin 3 to 6) at three to six months after stroke (odds ratio (OR) 0.81, 95% confidence interval (CI) 0.73 to 0.90). Thrombolytic therapy increased the risk of symptomatic intracranial haemorrhage (OR 3.49, 95% CI 2.81 to 4.33) and death by three to six months after stroke (OR 1.31, 95% CI 1.14 to 1.50). Treatment within three hours of stroke appeared more effective in reducing death or dependency (OR 0.71, 95% CI 0.52 to 0.96) with no statistically significant adverse effect on death (OR 1.13, 95% CI 0.86 to 1.48). There was heterogeneity between the trials in part attributable to concomitant antithrombotic drug use (P = 0.02), stroke severity and time to treatment. Antithrombotic drugs given soon after thrombolysis may increase the risk of death.

AUTHORS' CONCLUSIONS

Overall, thrombolytic therapy appears to result in a significant net reduction in the proportion of patients dead or dependent in activities of daily living. This overall benefit was apparent despite an increase both in deaths (evident at seven to 10 days and at final follow up) and in symptomatic intracranial haemorrhages. Further trials are needed to identify which patients are most likely to benefit from treatment and the environment in which thrombolysis may best be given in routine practice.

Impact of hyperlipidemia and statins on ischemic stroke outcomes after intra-arterial fibrinolysis and percutaneous mechanical embolectomy

BACKGROUND

Endovascular recanalization therapies are an increasingly employed treatment strategy in acute cerebral ischemia. The determinants of the final clinical outcome after endovascular treatment have been understudied. We investigated the effects of hyperlipidemia and statins on acute ischemic stroke outcomes after endovascular procedures.

METHODS

An inquiry of a prospectively maintained stroke registry was conducted. Endovascular procedures were performed using recombinant tissue plasminogen activator, prourokinase or the Merci device within 12 hours after symptom onset. The analyzed outcomes were revascularization, hemorrhage and excellent functional outcome (Rankin score of 0-1 at 3 months). The analyses included chi(2) and Wilcoxon rank sum, logistic regression (for multivariate analyses with binary outcomes) and linear regression (for continuous outcomes). Significance was set at p < 0.05.

RESULTS

We included 142 patients, 80% treated with intra-arterial fibrinolysis, 22% with percutaneous mechanical embolectomy and 27% treated with intravenous fibrinolysis prior to endovascular intervention. Age (OR = 0.956, 95% CI = 0.927-0.986, p = 0.0041), National Institutes of Health Stroke Scale (NIHSS) score on admission (OR = 0.881, 95% CI = 0.812-0.957, p = 0.0025) and history of hyperlipidemia (OR = 0.284, 95% CI = 0.08-0.99, p = 0.0478) were negatively associated with excellent functional outcome at 3 months. Every 50 mg/dl increment in the total cholesterol level resulted in 64% decrease in the odds of excellent functional outcome (OR = 0.36, 95% CI = 0.447-0.882, p = 0.0253). History of hyperlipidemia decreased the likelihood of neurological improvement (p = 0.0462) and was associated with a higher NIHSS score at 7 days or discharge. Statin use was related to an average 6.5-unit NIHSS decrease at discharge (p = 0.0168). Statins were not associated with increased frequency of recanalization or symptomatic intracerebral hemorrhage.

CONCLUSIONS

History of hyperlipidemia may have a negative impact on the outcomes of acute ischemic stroke treated with intra-arterial fibrinolysis or percutaneous mechanical embolectomy. Statin use before and after these procedures may be related to better neurological outcomes. Larger prospective studies are needed to endorse these findings.

Intra-arterial thrombolysis for acute central retinal artery occlusion

OBJECTIVE

In this study, we aimed at exploring the effect and safety of local intra-arterial thrombolysis on acute central retinal artery occlusion.

METHODS

Retrospective data analysis of 49 consecutive acute central retinal occlusion patients was performed. All the patients were treated with urokinase perfusion through the ophthalmology artery within the first 6 hours after central retinal artery occlusion attack. Conventional treatments including intra-ocular pressure decreasing, microcirculation improvement, neuroprotection and antiplatelet aggregation were conducted. The visual acuity (with International Snellen Chart) and field of vision were detected after thrombolysis. The complications and adverse events were observed.

RESULTS

Recanalization was found in 71% of patients. The visual acuity improvement was greater in the recanalization group (n=35) than in the non-recanalization group (n=14). The averaged visual acuity was 0.15+/-0.02, 0.25+/-0.03 and 0.4+/-0.05 after 2, 28 days and 6 months, respectively. Of the patients, 24.5% regained >0.6 of visual acuity, and the visual field deficit was less than 30% in 34.7% of patients after 28 days. Six months later, 36.7% patients regained visual acuity of >0.6, and the field deficit was less than 30% in 44.9% of patients. The difference between visual acuity in recanalization (0.6+/-0.04) and non-recanalization (0.002+/-0.0012) patients after 6 months after thrombolysis was significant (p>0.05).

CONCLUSIONS

Intra-arterial thrombolysis could obviously improve the short- and long-term visual function for patients with acute central retinal artery occlusion within 6 hours of symptom onset.

The penumbra pivotal stroke trial: safety and effectiveness of a new generation of mechanical devices for clot removal in intracranial large vessel occlusive disease

BACKGROUND AND PURPOSE

The purpose of this clinical evaluation was to assess the safety and effectiveness of the Penumbra System in the revascularization of patients presenting with acute ischemic stroke secondary to intracranial large vessel occlusive disease.

METHODS

In this prospective, multicenter, single-arm study, 125 patients with neurological deficits as defined by a National Institutes of Health Stroke Scale score > or =8, presented within 8 hours of symptom onset, and an angiographic occlusion (Thrombolysis In Myocardial Infarction [TIMI] Grade 0 or 1) of a treatable large intracranial vessel were enrolled. Patients who presented within 3 hours from symptom onset had to be ineligible or refractory to recombinant tissue plasminogen activator therapy. All patients were followed clinically for 90 days postprocedure.

RESULTS

A total of 125 target vessels in 125 patients were treated by the Penumbra System. Postprocedure, 81.6% of the treated vessels were successfully revascularized to TIMI 2 to 3. There were 18 procedural events reported in 16 patients (12.8%), 3 patients (2.4%) had events that were considered serious. A total of 35 patients (28%) were found to have intracranial hemorrhage on 24-hour CT of which 14 (11.2%) were symptomatic. All cause mortality was 32.8% at 90 days with 25% of the patients achieving a modified Rankin Scale score of < or =2.

CONCLUSIONS

These results suggest the Penumbra System allows safe and effective revascularization in patients experiencing ischemic stroke secondary to large vessel occlusive disease who present within 8 hours from symptom onset.

Stroke Therapy Academic Industry Roundtable (STAIR) recommendations for extended window acute stroke therapy trials

The Stroke Therapy Academic Industry Roundtable (STAIR) meetings focus on helping to advance the development of acute stroke therapies. Further extending the time window for acute stroke therapies is an important endeavor for increasing the number of stroke patients who might benefit from treatment. The STAIR group recommends that future extended time window trials initially should focus on selected patient groups most likely to respond to investigational therapies and that penumbral imaging is one tool that may identify such patients. The control group in these trials should receive best locally available medical care; if regulatory approval for intravenous (i.v.) tPA is extended to 4.5 hours, then tPA will become the most appropriate comparator in trials conducted within this time window. In future well-designed extended window clinical trials randomization is appropriate and should not be precluded by using unproven treatment with intraarterial (i.a.) thrombolysis or mechanical devices. For proof of concept, extended time window, phase II trials of i.v. thrombolysis, or mechanical devices in which early recanalization/reperfusion is the primary end point, rescue therapy/bailout treatment with i.a. thrombolysis or devices may be acceptable. Statistical considerations and definitions of successful recanalization/reperfusion are suggested for these trials.

Differences in psychometric properties, cut-off scores, and outcomes between the Barthel Index and Modified Rankin Scale in pharmacotherapy-based stroke trials: systematic literature review

OBJECTIVE

Review published clinical trial studies on pharmacological treatment of stroke using both the Barthel Index (BI) and Modified Rankin Scale (MRS) as outcome measures, and to highlight the differences in psychometric properties and cut-off scores through a systematic review.

METHODS

A systematic literature search on stroke studies involving a pharmacological treatment was conducted between 1955-2008. Key words included Barthel index, Rankin, modified Rankin, pharmacotherapy, validity, reliability, responsiveness, sensitivity, specificity, outcomes, psychometrics, prediction, randomized clinical trials, analysis, and stroke. All search terms were limited to Medical Subjects Headings (MESH) terms, English-language abstracts, and human subjects.

RESULTS

Overall, 44 studies were identified, six studies comparing the psychometric properties of the BI and the MRS, 24 studies on use of both the BI and the MRS in clinical stroke trials involving a pharmacological treatment, and 14 studies reviewed the cut-off scores and statistical issues related to scale selection. Most studies measured outcomes at 90 days after initiating therapy although differences were observed in this lag time. There was inconsistency in cut-off points used for both scales in the studies. There was no apparent relation between time to initiation of stroke therapy and outcomes measured by the BI and the MRS. The time window ranged from 3 hours to 72 hours although most of the studies reported outcomes after therapy initiation within 3-6 hours of stroke onset. BI may not be an appropriate scale to measure treatment effects due to the inherent ceiling and floor effects. Use of total distribution scores on the scales rather that dichotomizing or trichotomizing the scales has been favored recently. In mild to moderate stroke patients, the MRS seems to detect small and significant treatment effect changes as compared to the BI. Since most stroke studies try to exhibit the effects of treatment within 3 hours after symptom onset, the MRS might be more relevant to clinicians and patients receiving early intervention. Key limitations of this review are absence of studies that might have been identified through databases other than PubMed and MEDLINE and exclusion of non-pharmacological stroke trials that used the BI and the MRS for outcome measurement.

CONCLUSIONS

Despite the lack of uniformity in the cut-off points used in the trials, the follow-up time after administration of therapy, and the amount of time within which treatment is initiated after onset of stroke symptoms, the MRS seems to be more sensitive and responsive as compared to the BI in measuring stroke disability. However, more studies are required to differentiate the BI and the MRS that would help in selecting a scale that would appropriately capture outcomes among stroke patients.