Thrombolysis in acute ischemic stroke: does it work?

Thrombolysis for acute ischaemic stroke

BACKGROUND

Most 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 improve recovery after stroke in some people. 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 selected patients within 4.5 hours of stroke in Europe and within three hours in the USA. There is an upper age limit of 80 years in some countries, and a limitation to mainly non-severe stroke in others. Forty per cent more data are available since this review was last updated in 2009.

OBJECTIVES

To determine whether, and in what circumstances, thrombolytic therapy might be an effective and safe treatment for acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched November 2013), MEDLINE (1966 to November 2013) and EMBASE (1980 to November 2013). We also handsearched conference proceedings and journals, searched reference lists and contacted pharmaceutical companies and trialists.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Two review authors applied the inclusion criteria, extracted data and assessed trial quality. We verified the extracted data with investigators of all major trials, obtaining additional unpublished data if available.

MAIN RESULTS

We included 27 trials, involving 10,187 participants, testing urokinase, streptokinase, rt-PA, recombinant pro-urokinase or desmoteplase. Four trials used intra-arterial administration, while the rest used the intravenous route. Most data come from trials that started treatment up to six hours after stroke. About 44% of the trials (about 70% of the participants) were testing intravenous rt-PA. In earlier studies very few of the participants (0.5%) were aged over 80 years; in this update, 16% of participants are over 80 years of age due to the inclusion of IST-3 (53% of participants in this trial were aged over 80 years). Trials published more recently utilised computerised randomisation, so there are less likely to be baseline imbalances than in previous versions of the review. More than 50% of trials fulfilled criteria for high-grade concealment; there were few losses to follow-up for the main outcomes.Thrombolytic therapy, mostly administered up to six hours after ischaemic stroke, significantly reduced the proportion of participants who were dead or dependent (modified Rankin 3 to 6) at three to six months after stroke (odds ratio (OR) 0.85, 95% confidence interval (CI) 0.78 to 0.93). Thrombolytic therapy increased the risk of symptomatic intracranial haemorrhage (OR 3.75, 95% CI 3.11 to 4.51), early death (OR 1.69, 95% CI 1.44 to 1.98; 13 trials, 7458 participants) and death by three to six months after stroke (OR 1.18, 95% CI 1.06 to 1.30). Early death after thrombolysis was mostly attributable to intracranial haemorrhage. Treatment within three hours of stroke was more effective in reducing death or dependency (OR 0.66, 95% CI 0.56 to 0.79) without any increase in death (OR 0.99, 95% CI 0.82 to 1.21; 11 trials, 2187 participants). There was heterogeneity between the trials. Contemporaneous antithrombotic drugs increased the risk of death. Trials testing rt-PA showed a significant reduction in death or dependency with treatment up to six hours (OR 0.84, 95% CI 0.77 to 0.93, P = 0.0006; 8 trials, 6729 participants) with significant heterogeneity; treatment within three hours was more beneficial (OR 0.65, 95% CI 0.54 to 0.80, P < 0.0001; 6 trials, 1779 participants) without heterogeneity. Participants aged over 80 years benefited equally to those aged under 80 years, particularly if treated within three hours of stroke.

AUTHORS' CONCLUSIONS

Thrombolytic therapy given up to six hours after stroke reduces the proportion of dead or dependent people. Those treated within the first three hours derive substantially more benefit than with later treatment. This overall benefit was apparent despite an increase in symptomatic intracranial haemorrhage, deaths at seven to 10 days, and deaths at final follow-up (except for trials testing rt-PA, which had no effect on death at final follow-up). Further trials are needed to identify the latest time window, whether people with mild stroke benefit from thrombolysis, to find ways of reducing symptomatic intracranial haemorrhage and deaths, and to identify the environment in which thrombolysis may best be given in routine practice.

Factors associated with early hospital arrival in acute ischemic stroke patients

Early diagnosis and treatment in acute ischemic stroke are crucial in terms of survival and disability. Many stroke patients remain disabled because of the treatment delay. The purpose of this study was to investigate the factors associated with the early hospital arrival in acute ischemic stroke patients. 113 patients diagnosed with acute ischemic stroke were included in this prospective study performed at the Karadeniz Technical University Medical Faculty Hospital. Patients' characteristics and patients' and relatives' emotional and behavioral reactions were compared between early (within 3 h) and late (after 3 h) arrival groups. 72.6 % of patients arrived at hospital within 3 h from symptoms onset. Univariate analysis revealed that history of atrial fibrillation (p = 0.04) and coronary heart disease (p = 0.02), sudden onset of symptoms (p = 0.001), loss of consciousness (p = 0.03), recognizing symptoms as stroke (p = 0.01), seeking immediate medical attention (p < 0.001), feelings of fear and panic (p = 0.001), arriving at hospital by ambulance having called the emergency medical services (p = 0.04) and National Institute of Health Stroke Scale (NIHSS) score (p = 0.001) were associated with hospital arrival within 3 h. A multivariate regression model demonstrated that recognizing symptoms as stroke (OR, 3.4; 95 % CI, 1.2-9.3) and atrial fibrillation (OR, 4.3; 95 % CI, 1.1-15.7) were independent factors associated with early arrival. The role in early arrival at hospital of recognizing symptoms as stroke and seeking immediate medical attention with transportation by ambulance emphasize the importance of public awareness concerning recognizing the symptoms of stroke and accessing emergency medical assistance.

Intra-arterial thrombolysis in acute ischemic stroke: a review of pharmacologic approaches

Ischemic stroke is a major public health problem worldwide. The potential to cure stroke patients with intravenous thrombolytic therapy has evolved to the use of intra-arterial thrombolytic agents. Fewer than 200 patients have been enrolled in randomized trials of intra-arterial therapy. In this article the authors have reviewed the literature listed in MEDLINE and EMBase, and searched relevant articles to examine the role of fibrinolytic agents in acute interventional stroke therapy. Only English language articles reporting five or more patients were included. Outcomes were defined at 90 days. Good outcome was defined on the modified Rankin Scale. Symtpomatic hemorrhage was defined as hemorrhage in the setting of clinical deterioration in the first 24 to 48 h. The search identified 57 studies of which 44 reported usable data. Only three randomized trials were reported. Of a total of 1140 patients, most (73%) were treated open-label with urokinase (Abbokinase, Abbott Laboratories). The best outcomes were reported in case series and slightly worse outcomes were reported in clinical trials. Overall, it was not possible to distinguish whether one agent was superior to the others. There is a paucity of published evidence on intra-arterial therapy for acute ischemic stroke. Alteplase (Activase, Genentech Inc.) is currently the drug of choice simply because it is available and it is the current intravenous standard. Further trials and developments are anticipated.

Recombinant tissue plasminogen activator for acute ischaemic stroke: an updated systematic review and meta-analysis

BACKGROUND

Recombinant tissue plasminogen activator (rt-PA, alteplase) improved functional outcome in patients treated soon after acute ischaemic stroke in randomised trials, but licensing is restrictive and use varies widely. The IST-3 trial adds substantial new data. We therefore assessed all the evidence from randomised trials for rt-PA in acute ischaemic stroke in an updated systematic review and meta-analysis.

METHODS

We searched for randomised trials of intravenous rt-PA versus control given within 6 h of onset of acute ischaemic stroke up to March 30, 2012. We estimated summary odds ratios (ORs) and 95% CI in the primary analysis for prespecified outcomes within 7 days and at the final follow-up of all patients treated up to 6 h after stroke.

FINDINGS

In up to 12 trials (7012 patients), rt-PA given within 6 h of stroke significantly increased the odds of being alive and independent (modified Rankin Scale, mRS 0-2) at final follow-up (1611/3483 [46·3%] vs 1434/3404 [42·1%], OR 1·17, 95% CI 1·06-1·29; p=0·001), absolute increase of 42 (19-66) per 1000 people treated, and favourable outcome (mRS 0-1) absolute increase of 55 (95% CI 33-77) per 1000. The benefit of rt-PA was greatest in patients treated within 3 h (mRS 0-2, 365/896 [40·7%] vs 280/883 [31·7%], 1·53, 1·26-1·86, p<0·0001), absolute benefit of 90 (46-135) per 1000 people treated, and mRS 0-1 (283/896 [31·6%] vs 202/883 [22·9%], 1·61, 1·30-1·90; p<0·0001), absolute benefit 87 (46-128) per 1000 treated. Numbers of deaths within 7 days were increased (250/2807 [8·9%] vs 174/2728 [6·4%], 1·44, 1·18-1·76; p=0·0003), but by final follow-up the excess was no longer significant (679/3548 [19·1%] vs 640/3464 [18·5%], 1·06, 0·94-1·20; p=0·33). Symptomatic intracranial haemorrhage (272/3548 [7·7%] vs 63/3463 [1·8%], 3·72, 2·98-4·64; p<0·0001) accounted for most of the early excess deaths. Patients older than 80 years achieved similar benefit to those aged 80 years or younger, particularly when treated early.

INTERPRETATION

The evidence indicates that intravenous rt-PA increased the proportion of patients who were alive with favourable outcome and alive and independent at final follow-up. The data strengthen previous evidence to treat patients as early as possible after acute ischaemic stroke, although some patients might benefit up to 6 h after stroke.

FUNDING

UK Medical Research Council, Stroke Association, University of Edinburgh, National Health Service Health Technology Assessment Programme, Swedish Heart-Lung Fund, AFA Insurances Stockholm (Arbetsmarknadens Partners Forsakringsbolag), Karolinska Institute, Marianne and Marcus Wallenberg Foundation, Research Council of Norway, Oslo University Hospital.

A subpopulation of endothelial progenitor cells with low aldehyde dehydrogenase activity attenuates acute ischemic brain injury in rats

Previous studies have examined the therapeutic effect of endothelial progenitor cells (EPCs) during the chronic phase of cerebral infarction in rats; however, few studies have investigated the effects of EPCs during the acute phase of infarction. In this study, we evaluated the therapeutic effect of EPCs with low aldehyde dehydrogenase activity (Alde-Low EPCs) in rats with acute cerebral infarction, and our results provide insight that may help to identify a therapeutic mechanism of EPCs for acute cerebral infarction. The administration of Alde-Low EPCs into rats with acute cerebral infarction results in the accumulation and migration of the Alde-Low EPCs into the infarct area and the subsequent decrease of infarct volume. Moreover, we found that the stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) signaling pathway may regulate the accumulation of Alde-Low EPCs. The transplantation of Alde-Low EPCs may represent a potential treatment strategy for acute cerebral infarction.

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.

Urgent Intracranial Angioplasty after Combined Systemic and Intra-Arterial Thrombolysis in Acute Stroke

We report a case of a 59-year-old man who presented with an acute stroke involving the territory of his left middle cerebral artery, and who was treated with combined systemic and intra-arterial thrombolysis. After these treatments, the segment remained stenotic. An urgent intracranial angioplasty was performed, resulting in satisfactory recanalization of the stenotic segment, and significant improvement of his National Institutes of Health Stroke Scale (NIHSS) from 14 to 5. This case report suggests an effective alternate protocol for treatment of acute stroke with arterial occlusion: immediate smaller dose of IV tissue plasminogen activator (tPA), followed by angiogram, intra-arterial thrombolysis, and angioplasty if indicated.

Tongxinluo capsule for acute stroke

BACKGROUND

Tongxinluo capsules are a compound of Chinese traditional medicine which contain substances that are thought to have vasodilatory, antiplatelet, anticoagulant, thrombolytic and even lipid-lowering properties, and therefore may improve outcome after acute ischaemic stroke. To date the evidence of its effect has not been systematically reviewed, making it difficult to derive robust conclusions about its actual benefits, and indeed, possible harms.

OBJECTIVES

To assess the effectiveness and possible harms of tongxinluo capsule for acute cerebral infarction compared with control.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register (last searched on 24 January 2008) the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2007), MEDLINE (1995 to 2006), EMBASE (1995 to 2006), China National Knowledge Infrastructure (CNKI, 1994 to 2006), CBM (Chinese Biomedical Database) (1995 to 2006), Current Controlled Trials (www.controlled-trials.com), National Research Register (http://www.update-software.com/national/). We handsearched 30 journals (1995 to 2006), and contacted drug companies and the principal of included trials.

SELECTION CRITERIA

Randomised controlled trials comparing tongxinluo with placebo or open control (or tongxinluo plus standard therapy versus standard therapy alone) in people with definite acute stroke. We excluded trials if they sought to recruit patients with transient ischaemic attacks (TIA), intracerebral haemorrhage, heart failure, or renal failure.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and assessed trial quality.

MAIN RESULTS

Only two poor quality studies with a total of 232 participants were included in this review. Neither study reported any of our pre-specified outcomes, so no reliable estimate of the effect of treatment on major clinical outcomes could be obtained.

AUTHORS' CONCLUSIONS

It was not possible to reliably determine whether tongxinluo has a favourable or unfavourable effect in acute ischaemic stroke. High quality trials are required to assess the efficacy and safety of tongxinluo capsule for acute ischaemic stroke.

Reperfusion Therapy for Acute Middle Cerebral Artery Trunk Occlusion. Direct Percutaneous Transluminal Angioplasty Versus Intra-arterial Thrombolysis

SUMMARY

The purpose of this study was to test the hypothesis that direct percutaneous transluminal angioplasty (PTA) might reduce the incidence of haemorrhagic complications and might improve recanalization rate and clinical outcome as compared with intra-arterial (IA) thrombolysis in patients with acute middle cerebral artery (MCA) trunk occlusion. A total of 70 patients with acute MCA trunk occlusion were treated with IA reperfusion therapy. Thirty-six patients were treated with IA thrombolysis alone. In the other 34 patients, direct PTA was selected as the first choice of the treatment and subsequent thrombolysis was added if necessary for distal embolization. The modified Rankin scale (mRS) was used to assess clinical outcome at 90 days. As compared with IA thrombolysis, direct PTA provided significant increase in the rates of partial or complete recanalization (63.9 vs 91.2%, p < 0.01) and decrease in the incidence of large parenchymal hematoma with neurological deterioration (19.4% vs 2.9%, p=0.03). Despite such favorable effects, direct PTA did not improve the rate of a favorable outcome (mRS score 0 or 1, 41.7% for the IA thrombolysis group vs 52.9% for the PTA group, p=0.48). However, outcome classified in terms of independence (mRS score </= 2) was significantly better in the PTA group (73.5%) than the IA thrombolysis group (50.0%, p=0.04). In patients with acute MCA trunk occlusion, as compared with IA thrombolysis, direct PTA improved recanalization rate and reduced serious haemorrhagic complications, resulting in a significant increase in independent patients.

Multidetector computed tomography of the head in acute stroke: predictive value of different patterns of the dense artery sign revealed by maximum intensity projection reformations for location and extent of the infarcted area

Maximum intensity projections reconstructions from 2.5 mm unenhanced multidetector computed tomography axial slices were obtained from 49 patients within the first 6 h of anterior-circulation cerebral strokes to identify different patterns of the dense artery sign and their prognostic implications for location and extent of the infarcted areas. The dense artery sign was found in 67.3% of cases. Increased density of the whole M1 segment with extension to M2 of the middle cerebral artery was associated with a wider extension of cerebral infarcts in comparison to M1 segment alone or distal M1 and M2. A dense sylvian branch of the middle cerebral artery pattern was associated with a more restricted extension of infarct territory. We found 62.5% of patients without a demonstrable dense artery to have a limited peripheral cortical or capsulonuclear lesion. In patients with a 7-10 points on the Alberta Stroke Early Programme Computed Tomography Score and a dense proximal MCA in the first hours of ictus the mean decrease in the score between baseline and follow-up was 5.09+/-1.92 points. In conclusion, maximum intensity projections from thin-slice images can be quickly obtained from standard computed tomography datasets using a multidetector scanner and are useful in identifying and correctly localizing the dense artery sign, with prognostic implications for the entity of cerebral damage.

Thrombolytic Therapy: Current Clinical Practice

Thrombolytic therapy is an essential tool in the array of therapies designed to reopen arteries and veins occluded with thrombus. As the use of thrombolytic agents has entered mainstream practice, their application has expanded to include a wide variety of indications and settings. Thrombolytic agents are used in patients who have thrombosis of coronary arteries, precerebral and cerebral arteries, the aorta, iliac and mesenteric arteries, and peripheral arteries. The use of thrombolysis in venous thrombosis has included deep venous thrombosis of the upper and lower extremities and vena cava, mesenteric veins, cerebral veins, and central access catheters. Guidelines are available from the American College of Cardiology/American Heart Association regarding thrombolysis in myocardial infarction and from the American Stroke Association regarding thrombolysis in acute ischemic stroke.

Comparison of intravenous and intra-arterial urokinase thrombolysis for acute ischaemic stroke

Intravenous fibrinolysis (IVF) with rt-PA (alteplase) provides significant benefits in acute ischaemic stroke when it is given within the first three hours following stroke onset. Intra-arterial fibrinolysis (IAF) with pro-urokinase in PROACT II study provides quite the same benefit in the first 6 hours. IVF and IAF have never been compared. To compare the efficacy and safety of IVF and IAF with urokinase given within the first 6 hours of acute ischaemic stroke. Patients fulfilling the selection criteria were randomly assigned to receive urokinase 900,000 units via intravenous or intra-arterial routes. This randomised monocentre study was done between December 1995 and August 1997. The primary outcome was defined as the number of patients with a modified Rankin score of 2 or less. Secondary outcomes included mortality, frequency of symptomatic intracranial haemorrhage (SIH), neurological and functional scores. Fourteen patients were given IVF and 13 IAF. The study was terminated by the National Health Authorities when 27 patients had been included because of the mortality rate. Seven patients (26%) died, 4 in the IV group (oedematous infarct in 3 and recurrence in 1), 3 in the IA group (SIH in 2, and oedematous infarct in 1). Patients given IVF were treated significantly earlier (4:16 h vs 5:24 h; p=.007). Although IA patients showed greater and earlier improvement there was no significant difference in primary and secondary outcomes. Because of premature termination, the trial was too small to provide any reliable and conclusive results. Intra-arterial fibrinolysis began significantly later than IV fibrinolysis but it gave non-significantly better results in this prematurely terminated study.

Intraarterial Thrombolytic Therapy within 3 Hours of the Onset of Stroke

OBJECTIVE

The National Institute of Neurological Disorders and Stroke (NINDS) Recombinant Tissue Plasminogen Activator Stroke Study Group showed that recombinant tissue plasminogen activator (rt-PA) administered intravenously within 3 hours of the onset of ischemic stroke can improve clinical outcome. Intraarterial (IA) thrombolysis has been shown to offer advantages over intravenous (IV) thrombolysis, but experience with this type of therapy within 3 hours of the onset of symptoms has not been reported previously. This study is the first retrospective analysis of a two-institution experience with IA thrombolysis within 3 hours of stroke onset.

METHODS

A total of 36 patients with angiographically demonstrated occlusions were treated with urokinase or rt-PA within 3 hours of stroke onset. Outcome measures included the percentage of patients with no or minimal neurological disability at 30 to 90 days as measured by the modified Rankin Scale, percentage recanalization, incidence of symptomatic intracranial hemorrhage, and mortality rate. The results were compared with those of the NINDS rt-PA study.

RESULTS

The median admission National Institutes of Health Stroke Scale score was 14. Fifty percent of treated patients had a modified Rankin Scale score of 0 or 1 indicating no or little disability at 1 to 3 months compared with 39% of treated patients in the NINDS trial. Recanalization was 75%, symptomatic intracranial hemorrhage was 11% (versus 6.4% with IV rt-PA in the NINDS trial), and the mortality rate was 22% (versus 17% with IV rt-PA in the NINDS trial).

CONCLUSION

The results suggest that IA thrombolysis administered within 3 hours of stroke onset is a feasible and viable alternative to IV rt-PA on the basis of improved clinical outcomes, high recanalization percentage, and comparable mortality rate and despite increased symptomatic intracranial hemorrhage. Whether IA thrombolysis is superior to IV therapy awaits further study.

Intraarterial Thrombolysis with r-tPA for Treatment of Anterior Circulation Acute Ischemic Stroke. Technical and Clinical Results

SUMMARY

To investigate factors effecting the safety and recanalization efficacy of local intraarterial (IA) recombinant tissue plasminogen activator (r-tPA) delivery in patients with acute ischemic stroke. Eleven patients with anterior circulation acute ischemic stroke were treated. The neurological status of the patients were graded with the Glasgow Coma Scale (GCS) and National Institute of Health Stroke Scale (NIHSS). All patients underwent a computed tomography (CT) examination at admission. In addition four patients had diffusion-weighted and one patient had a perfusion magnetic resonance (MR) examinations. Patients were treated within six hours from stroke onset. Immediate, six hours, and 24 hours follow-up CT examinations were performed in order to evaluate the haemorrhagic complications and the extent of the ischemic area. The Rankin Scale (RS) was used as an outcome measure. Two of the 11 patients had carotid "T" occlusion (CTO), nine had middle cerebral artery (MCA) main trunk occlusion. Four patients had symptomatic haemorrhage with a large haematoma rupturing into the ventricles and subarachnoid space. Of these, three patients died within 24 hours. The remaining seven patients had asymptomatic haematomas that were smaller compared to symptomatic ones, and showed regression in size and density on follow-up CTs. At third month five patients had a good outcome and three patients had a poor outcome. In acute ischemic stroke, local IA thrombolysis is a feasible treatment when you select the right patient. Haemorrhage rate does not seem to exceed that occuring in the natural history of the disease and in other treatment modalities.

Thrombolytic therapy: clinical applications

The therapeutic use of thrombolytic agents is the result of the increasing understanding of the pathophysiologic mechanisms underlying normal and deranged thrombosis and fibrinolysis. Plasminogen activators capable of increasing the production of plasmin exhibit considerable efficacy in the treatment of a variety of arterial and venous thrombotic disorders. The ideal thrombolytic agent has not been developed, but the desired clinical result of rapid opening of the thrombosed vessel without reocclusion, without activation of systemic fibrinogenolysis, and without a risk of hemorrhage are defined. Clinical studies clearly demonstrate that the addition of a variety of adjunctive agents to available thrombolytics enhances benefit without inordinate risk. The addition of intravascular angioplasty and stenting to thrombolysis increases the potential long-term benefit. Newer thrombolytic agents and new protocols for the use of existing therapies offer the promise of saving many who would otherwise succumb to coronary or cerebral arterial thrombosis or to venous thromboembolism.

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. Successful treatment could mean that the patient is more likely to make a good recovery from their stroke. Thrombolytic drugs however, can also cause serious bleeding in the brain which can be fatal. Thrombolytic therapy has now been evaluated in several randomised trials in acute ischaemic stroke.

OBJECTIVES

The objective of this review was 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 January 2003), MEDLINE (1966- January 2003) and EMBASE (1980-January 2003). In addition we contacted researchers and pharmaceutical companies, attended relevant conferences and handsearched four Japanese journals.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

One reviewer applied the inclusion criteria and extracted the data. Trial quality was assessed. The extracted data were verified by the principal investigators of all major trials. Thus published and unpublished data were obtained where available.

MAIN RESULTS

Eighteen trials including 5727 patients were included, but not all trials contributed data to each outcome examined in this review. Sixteen trials were double-blind. The trials tested urokinase, streptokinase, recombinant tissue plasminogen activator or recombinant pro-urokinase. Two trials used intra-arterial administration but the rest used the intravenous route. About 50% of the data (patients and trials) come from trials testing intravenous tissue plasminogen activator. There are few data from patients aged over 80 years. Much of the data comes from trials conducted in the first half of the 1990s when, in an effort to reduce delays to trial drug administration, on site randomisation methods were used that, in consequence, limited the ability to stratify randomisation on key prognostic variables. Several trials, because of the biological effects of thrombolysis combined with the follow-up methods used, did not have complete blinding of outcome assessment. Thrombolytic therapy, 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 the end of follow-up at three to six months (OR 0.84, 95% CI 0.75 to 0.95). This was in spite of a significant increase in : the odds of death within the first ten days (odds ratio [OR] 1.81, 95% confidence interval [CI] 1.46 to 2.24), the main cause of which was fatal intracranial haemorrhage (OR 4.34, 95% CI 3.14 to 5.99). Symptomatic intracranial haemorrhage was increased following thrombolysis (OR 3.37, 95% CI 2.68 to 4.22). Thrombolytic therapy also increased the odds of death at the end of follow-up at three to six months (OR 1.33, 95% CI 1.15 to 1.53). For patients treated within three hours of stroke, thrombolytic therapy appeared more effective in reducing death or dependency (OR 0.66, 95% CI 0.53 to 0.83) with no statistically significant adverse effect on death (OR 1.13, 95% CI 0.86 to 1.48). There was heterogeneity between the trials that could have been due to many trial features including : thrombolytic drug used, variation in the use of aspirin and heparin, severity of the stroke (both between trials and between treatment groups within trials), and time to treatment. Trials testing intravenous recombinant tissue plasminogen activator suggested that it may be associated with slightly less hazard and more benefit than other drugs when given up to six hours after stroke but these are non-random comparisons - death within the first ten days OR 1.24, 95% CI 0.85 to 1.81, death at the end of follow-up OR 1.17, 95% CI 0.95 to 1.45, dead or dependent at the end of follow-up OR 0.80, 95% CI 0.69 to 0.93. However, no trial has directly comparedup OR 0.80, 95% CI 0.69 to 0.93. However, no trial has directly compared rt-PA with any other thrombolytic agent. There is some evidence that antithrombotic drugs given soon after thrombolysis may increase the risk of death.

REVIEWER'S 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. However, this appears to be net of an increase in deaths within the first seven to ten days, symptomatic intracranial haemorrhage, and deaths at follow-up at three to six months. The data from trials using intravenous recombinant tissue plasminogen activator, from which there are the most evidence on thrombolytic therapy so far, suggest that it may be associated with less hazard and more benefit. There was heterogeneity between the trials for some outcomes and the optimum criteria to identify the patients most likely to benefit and least likely to be harmed, the latest time window, the agent, dose, and route of administration, are not clear. The data are promising and may justify the use of thrombolytic therapy with intravenous recombinant tissue plasminogen activator in experienced centres in highly selected patients where a licence exists. However, the data do not support the widespread use of thrombolytic therapy in routine clinical practice at this time, but suggest that further trials are needed to identify which patients are most likely to benefit from treatment and the environment in which it may best be given. To avoid the problem of data missing from some trials for some key outcomes encountered in this review to date, and to assist future metaanalyses, future trialists should try to collect data in such a way as to be compatible with the basic outcome assessments reviewed here (eg early death, fatal intracranial haemorrhage, poor functional outcome).

Thrombolytic therapy

The therapeutic use of thrombolytic agents is the natural result of the increasing understanding of the pathophysiologic mechanisms underlying normal and deranged thrombosis and fibrinolysis. Plasminogen activators capable of increasing the production of plasmin exhibit considerable efficacy in the treatment of a variety of arterial and venous thrombotic disorders. The ideal thrombolytic agent has yet to be developed but the desired clinical result of rapid opening of the thrombosed vessel without reocclusion, without activation of systemic fibrinogenolysis, and without a risk of hemorrhage is well defined. Clinical studies clearly demonstrate that the addition of a variety of adjunctive agents to the available thrombolytics enhances benefit without inordinate risk. The addition of intravascular angioplasty and stenting to thrombolysis increases the potential long-term benefit. Newer thrombolytic agents and new protocols for the use of existing therapies offer the promise of saving many who would otherwise succumb to coronary or cerebral arterial thrombosis or to venous thromboembolism.

Optimal timing of thrombolytic therapy in acute ischaemic stroke

The clinical benefit of thrombolytic therapy for patients experiencing acute cerebral ischaemia has been demonstrated by both clinical trials and phase IV studies. However, such treatments must be initiated in a rapid manner, with treating physicians adhering to strict protocols designed to minimise delays and maximise safety. The efficacy of intravenous drug administration has been established with alteplase (recombinant tissue plasminogen activator; tPA) and ancrod, but only if these drugs can be administered within 3 hours of symptom onset. The use of alteplase beyond this timeframe, or outside of established protocols, may be hazardous. The use of alternative intravenous thrombolytic agents, such as streptokinase, also appears hazardous. Intra-arterial delivery of thrombolytic drugs such as pro-urokinase may extend clinical benefit to the 6-hour time frame.

Ischaemic brain oedema

Ischaemic brain oedema appears to involve two distinct processes, the relative contribution and time course of which depend on the duration and severity of ischaemia, and the presence of reperfusion. The first process involves an increase in tissue Na+ and water content accompanying increased pinocytosis and Na+, K+ ATPase activity across the endothelium. This is apparent during the early phase of infarction and before any structural damage is evident. This phenomenon is augmented by reperfusion. A second process results from a more indiscriminate and delayed BBB breakdown that is associated with infarction of both the parenchyma and the vasculature itself. Although, tissue Na+ level still seems to be the major osmotic force for oedema formation at this second stage, the extravasation of serum proteases is an additional potentially deleterious factor. The relative importance of protease action is not yet clear, however, degradation of the extracellular matrix conceivably leads to further BBB disruption and softening of the tissue, setting the stage for the most pronounced forms of brain swelling. A number of factors mediate or modulate ischaemic oedema formation, however, most current information comes from experimental models, and clinical data on this microcosmic level is lacking. Clinically significant brain oedema develops in a delayed fashion after large hemispheric strokes and is a cause of substantial mortality. Neurological signs appear to be at least as good as direct ICP measurement and neuroimaging in detecting and gauging the secondary damage produced by stroke oedema. The neuroimaging characteristics of the stroke, specifically the early involvement of greater than half of the MCA territory, are, however, highly predictive of the development of severe oedema over the subsequent hours and days. None of the available medical therapies provide substantial relief from the oedema and raised ICP, or at best, they are temporizing in most cases. Hemicraniectomy appears most promising as a method of avoiding death from brain compression, but the optimum timing and manner of patient selection are currently being investigated. All approaches to massive ischaemic brain swelling are clouded by the potential for survival with poor functional outcome. It is possible to manage blood pressure, serum osmolarity by way of selective fluid administration, and a number of other systemic factors that exaggerate brain oedema. Broad guidelines for treatment of stroke oedema can therefore be given at this time.

Selective Intra-arterial Thrombolysis for Embolic Complications of Cerebral Endovascular Therapy

SUMMARY

Cerebral thrombo-embolic complications seldom occur during intracranial endovascular therapeutic procedures. Yet, despite a systemic preventive regimen of pre-operative intravenous acetylsalicylic acid and effective systemic heparinisation, we encountered seven complications of this type over a period of five years, a 3.7 per thousand incidence (7/1858). Local intra-arterial thrombolysis performed immediately after the thrombo-embolic complication resulted in complete recanalization in five cases and partial recanalization in two. CT scans performed 24 hours after thrombolysis were normal in six of the seven patients. Only one female patient with partial recanalization showed a limited cortical infarct in the parietal distribution of the middle cerebral artery territory. In all seven cases recanalization of the occluded vessel resulted in a return to the baseline initial neurological status. This short series demonstrates the usefulness of emergent thrombolysis dealing with the thrombo-embolic complications of angiography or endovascular therapy. These results are in agreement with these experimental data showing that early recanalization can prevent macroscopically visible infarcts.

Evaluation of local intra-arterial fibrinolytic therapy for acute middle cerebral artery occlusion

SUMMARY

Fibrinolytic therapy for acute ischaemic stroke has been investigated in several clinical trials, with various protocols. This retrospective study was undertaken to evaluate the efficacy and limitation of local intra-arterial fibrinolytic therapy using urokinase (UK) in patients with acute middle cerebral artery occlusion. Fifty patients were treated with local intra-arterial fibrinolytic therapy within six hours after onset of symptoms. The median National Institutes of Health Stroke Scale (NIHSS) score was 17 (range, 6 to 28).Two hundred and forty thousand IU of UK was administered through a microcatheter for 20 minutes. When arterial recanalization was not achieved, a second or third infusion was performed. Maximum dosage of UK was 0.96 x 106 IU. Recanalization efficacy was evaluated at the end of fibrinolytic therapy and intracranial haemorrhage was assessed within 24 hours. Clinical outcome was evaluated three months after ictus with modified Rankin scale (RS). Thirty-nine patients (78%) obtained recanalization. Twenty-nine of 39 (74%) showed clinical improvement just after treatment. On the other hand, only 18% patients (2/11) who did not recanalize demonstrated improvement. Twenty-five of 50 (50%) patients recovered to RS score 0 or 1, however, only 28% of patients (5/18) with proximal M1 occlusion obtained good outcome and 39% of them (7/18) died. The mean time interval from onset to treatment did not affect outcome. The overall incidence of haemorrhagic event (HE) within 24 hours was 36%, however, 78% of patients with proximal M1 occlusion showed HE. Only one patient with HE clinically deteriorated. In conclusion, local intra-arterial fibrinolytic therapy could be a safe and effective method for acute middle cerebral artery occlusion, however, indication of this therapy for patients with proximal M1 occlusion should be carefully decided.

Usefulness of postischemic thrombolysis with or without neuroprotection in a focal embolic model of cerebral ischemia

OBJECT

Recent studies have shown that the use of thrombolysis in the setting of acute stroke is associated with an increased risk of cerebral hemorrhage. The time of onset of symptoms to initiation of medication and the dose levels of the thrombolytic agents are important determinants for the risk of cerebral hemorrhage. The authors evaluated the time course of thrombolysis-related hemorrhages in experimental settings and tested whether the addition of neuroprotective medication augments the efficacy of thrombolysis and reduces the incidence of hemorrhages.

METHODS

Male Wistar rats were subjected to right middle cerebral artery embolization with an autologous thrombus and were then randomly assigned to one of the following groups: Group 1, saline-treated (2 hours after ischemic insult) animals as controls; Groups 2 to 4, high-dose urokinase (5,000 U/kg) at 2, 3, and 6 hours after the insult; Group 5, low-dose urokinase (2,500 U/kg) at 2 hours after the insult; Group 6, 20 mg/kg topiramate (TPM) at 2 hours after the insult; Group 7, a combination of 20 mg/kg TPM at 2 hours and low-dose urokinase (2,500 U/kg) at 6 hours after the insult; and Group 8, 20 mg/kg TPM (20 mg/kg) at 2 hours and high-dose urokinase (5,000 U/kg) at 2 hours after the insult. Neurological behavior and the infarct volume in the brain were assessed following cerebral embolism and the various treatments. All animals in the single therapy and low-dose combination groups survived surgery. Three of eight animals treated with high-dose urokinase alone at 6 hours and three of six animals in the combined high-dose urokinase and TPM group developed fatal intracerebral hemorrhages. There was a significantly better neurological outcome at 24 hours in the animals treated with either medication compared with controls. The volume of the infarct in the saline-treated group was 54.2 +/- 9%. The use of TPM at 2 hours led to a decrease in the infarct to 20.1 +/- 11.2% (p < 0.01). Treatment with urokinase at 6 hours after the occlusion showed a trend toward protection; the infarct volume was 31.9 +/- 14.1% (p < 0.05). The addition of TPM to low- or high-dose urokinase achieved better neuroprotection (8.2 +/- 6% and 11.9 +/- 10.7%, respectively; both p < 0.01).

CONCLUSIONS

In this study the authors show that the volume of the infarct can be significantly decreased with 2 to 6-hour delayed intraarterial thrombolysis with urokinase and that the efficacy of thrombolysis may be enhanced by combining neuroprotective agents like TPM. It is also shown that low-dose combination therapy may decrease the likelihood of cerebral hemorrhage.

Intravenous low-dose native tissue plasminogen activator for distal embolism in the middle cerebral artery divisions or branches: a pilot study

OBJECTIVE

We prospectively evaluated the safety and efficacy of an intravenous infusion of low-dose native tissue plasminogen activator for distal embolisms in the middle cerebral artery divisions or branches.

METHODS

Twenty patients were selected according to the following computed tomographic and angiographic criteria and treated with intravenous infusion of 7.2 mg of tisokinase: 1) no early ischemic changes on the initial computed tomographic scan, and 2) embolic occlusion of the middle cerebral artery divisions or branches without the involvement of the lenticulostriate arteries. For comparison, the records of 12 patients from previous years who met the above inclusion criteria but underwent no thrombolytic therapy were reviewed retrospectively. The degree of neurological recovery was assessed using the National Institutes of Health Stroke Scale at 24 hours after admission. Major neurological improvement was defined as a decrease in the stroke score by 4 points or more.

RESULTS

There was no significant difference in stroke scores at the time of admission between the treatment group (mean +/- standard deviation, 12.8 +/- 2.8) and the untreated group (14.0 +/- 2.4). In the treatment group, major neurological improvement was seen in 17 (85%) of 20 patients, whereas in the untreated group only 5 (41.7%) of 12 patients showed major neurological improvement (P < 0.05). The mean score at 24 hours in the treatment group (3.6 +/- 3.5) was significantly lower than that in the untreated group (9.4 +/- 7.3) (P < 0.05). There was no hemorrhagic complication with neurological exacerbation in the treatment group.

CONCLUSION

Even with delayed initiation (>3 h after symptom onset), intravenous infusion of low-dose tisokinase may be safe and effective for small distal emboli in the middle cerebral artery divisions or branches, when early ischemic changes on computed tomographic scans and involvement of the lenticulostriate arteries are absent.

Evaluating the efficacy of citicoline in embolic ischemic stroke in rats: neuroprotective effects when used alone or in combination with urokinase

The combination of thrombolysis with neuroprotection, because of different mechanisms, would be expected to show better results when used after onset of focal ischemia. In this study we report our experience with the neuronal protective effects of citicoline alone and in combination with urokinase in a model of focal ischemia. Both medications were injected 2 h after onset of a focal occlusion of the middle cerebral artery (MCA) in rats. Focal ischemia was produced with embolization of a clot into the origin of the MCA. This produces a large infarction involving the cortex and the basal ganglia. Animals were observed for neuronal deficts at 2 and 24 h after surgery and were sacrificed 72 h after onset of ischemia. Saline-treated animals showed a large infarction involving the cerebral cortex and basal ganglion in most animals (volume 33.1 +/- 9.7%). Animals treated with citicoline alone were divided in two groups. The first group of animals were treated with a single injection (300 mg/kg, ip) of the medication 2 h after the arterial occlusion. The second group was treated with the active medication intermittently (3 x 300 mg/kg, ip) over a 72-h period. There was a significant decrease in the neuronal damage in the cortex in the animals treated with citicoline (single dose, 20.9 +/- 9.7%, P = 0.01; intermittent injection, 18.9 +/- 11.4%, P < 0.008). The last experiment evaluated the usefulness of the combination of citicoline with intraarterial urokinase. The combination showed significantly more protection than with urokinase or citicoline alone (volume 13.6 +/- 9.1%, P < 0.001). We conclude from our experiments that citicoline may offer significant neuronal protection that may be further enhanced with the addition of a thrombolytic agent.

Thrombolytic therapy for stroke: a review with particular reference to elderly patients

Clinical trials in the 1990s of intravenous thrombolysis for ischaemic stroke have involved over 3000 patients. Alteplase given within 3 hours of onset significantly reduces the combined end-point of death and disability. Although alteplase appears safe when given up to 6 hours after onset, individual trials have failed to confirm efficacy beyond 3 hours. Meta-analysis indicates that intravenous alteplase given up to 6 hours after stroke onset significantly reduces death or dependence 3 months after stroke. Two trials of intra-arterial pro-urokinase confirm benefits of treatment up to 6 hours in highly selected patients with angiographically confirmed proximal middle cerebral occlusion. Streptokinase increased the risk of early death significantly in 3 trials, with no overall reduction in eventual death and disability. Patients over 80 years have been excluded from most trials of alteplase, and experience in this age group is minimal. Increased incidence and poorer functional outcome in the elderly mean that thrombolysis may have greater absolute benefit in this group than in the young, but there is also a higher prevalence of absolute or relative potential contraindications to treatment (ranging from increased use of anticoagulant drugs to higher prevalence of atrial fibrillation). Further trials are necessary to address age restrictions and other important issues in the use of alteplase. Thrombolysis is likely to remain feasible for a minority of stroke patients of all ages, and there is a need for other acute treatment options.

Neutrophil and Platelet Activity and Quantification Following Delayed tPA Therapy in a Rabbit Model of Thromboembolic Stroke

Although there is considerable interest in the role of neutrophils and platelets in acute cerebral ischemia-reperfusion, there are very little data related to the effect of systemic thrombolytic therapy on these blood elements. In the present study a rabbit model was used to examine the effects of cerebral ischemia, tissue-plasminogen activator therapy, or both on neutrophil and platelet peripheral counts and activity, the latter studied by stimulated neutrophil and platelet impedance aggregation and neutrophil oxygen-free radical chemiluminescence. New Zealand white rabbits (n = 25) were randomized to receive either tissue-plasminogen activator (6.3 mg/kg IV; 20% bolus, remainder as a 2-hour infusion) or vehicle (0.9% saline) 3 hours following either autologous clot embolization or sham carotid artery isolation. Thus, four groups were examined: sham (n = 4), tPA only (n = 4), stroke only (n = 8), and stroke plus tPA (n = 9). Two hours after completion of thrombolytic therapy or vehicle infusion, the experiments were terminated, that is, 7 hours following autologous clot embolization or sham instrumentation. Blood was sampled from the thoracic aorta, and neutrophil and platelet peripheral counts and activity were determined prior to embolization and 0.5, 2.0, 4.0, and 7.0 hours following autologous clot embolization. No significant difference in platelet counts, either over time or between groups, was noted. In contrast to the platelet counts, the neutruphil count significantly increased over time, rising approximately 2.5-fold from baseline in all four groups (p < 0.001). No significant increase in neutrophil accumulation (myeloperoxidase assay; 10 (7) PMNs/g tissue; mean +/- SEM) was noted within infarcted regions of either the stroke (1.26 +/- 0.07; n = 5) or stroke plus tissue-plasminogen activator (1.26 +/- 0.09; n = 5) groups when compared to either viable brain regions within the ischemic hemisphere (1.29 +/- 0.03; n = 4) or in sham controls (1.36 +/- 0.35; n = 4). Neutrophil activity (aggregation, oxygen-free radical release) in both groups undergoing autologous clot embolization demonstrated a trend toward higher values when compared to the two sham-operated groups. Tissue-plasrninogen activator administration did not significantly affect ex vivo neutrophil activity. In contrast, platelet aggregation was significantly reduced by the administration of tPA with (p = 0.001) or without (p < 0.01) autologous clot embolization. Thus, in the present rabbit model platelet but not neutrophil activity is modulated by the administration of tissue-plasminogen activator, while autologous clot embolization results in a trend toward acute neutrophil activation.

Cerebral hemorrhagic complications of thrombolytic therapy

Thrombolytic therapy is well established in the management of a select group of atherothrombotic and thromboembolic diseases at the expense of definite but increased risk of intracranial hemorrhage. The incidence of intracranial hemorrhage is higher (6.4% to 20%) in the thrombolytic treatment of acute ischemic stroke, whereas the cerebral hemorrhagic complications of thrombolytic treatment in acute myocardial infarction, acute pulmonary embolism, deep venous thrombosis, and arterial and graft occlusion is less than 2%. Although systemic fibrinolysis after thrombolysis is responsible for hemorrhagic complications, many factors are implicated in predisposition to cerebral hemorrhagic complications such as old age, untreated or chronic hypertension, history of cardiac disease, hyperglycemia, patients with small body mass, previous stroke, longer therapeutic treatment window, increasing neurological deficit or severity of neurological deficit, higher thrombolytic dose and computed tomography findings of mass effect, edema, or extended infarct sign involving more than one third of the territory of the middle cerebral artery. Although the knowledge of different factors associated with intracranial hemorrhage is important, it is the judicious use and strict adherence of appropriate clinical protocols in different clinical settings of thrombolytic treatment and avoidance of the contra-indications that will minimize the rate of hemorrhagic complication to achieve good clinical outcome and desired benefit.

Neuroprotection in acute ischaemic stroke. II: Clinical potential

In the 4 years since our first article, there has been considerable progress in our understanding of the pathophysiology of acute ischaemic stroke, and the results of well-conducted trials have at last begun to change everyday clinical practice. The timing of the various processes of the ischaemic cascade and the potential time windows for different interventions are better understood. Furthermore, the importance of maintaining cerebral perfusion and optimizing systemic physiological and biochemical factors in order to prevent neurological deterioration ('progressing stroke') is increasingly being realized. Numerous antithrombotic and neuroprotective drugs have been evaluated in clinical trials, and while none has shown unequivocal benefits on its own, prospects for successful intervention are still good. This will probably involve different combinations of treatments targeted on different pathophysiological stroke types, so that the management of acute stroke will offer a considerable challenge to the stroke physicians of the future.

Imaging of acute cerebral ischemia

Until recently, there was no efficacious treatment for acute cerebral ischemia. As a result, the role of neuroimaging and the radiologist was peripheral in the diagnosis and management of this disease. The demonstration of efficacy using thrombolysis has redefined this role, with the success of intervention becoming increasingly dependent on timely imaging and accurate interpretation. The potential benefits of intervention have only begun to be realized. In this State-of-the-Art review of imaging of acute stroke, the role of imaging in the current and future management of stroke is presented. The role of computed tomography is emphasized in that it is currently the most utilized technique, and its value has been demonstrated in prospective clinical trials. Magnetic resonance techniques are equally emphasized in that they have the potential to provide a single modality evaluation of tissue viability and vessel patency in an increasingly rapid evaluation.

Embolectomy for acute embolic occlusion of the internal carotid artery bifurcation

BACKGROUND

Acute occlusion of the distal intracranial segment of the internal carotid artery (ICA) causes sudden severe hemispheric ischemia. A low rate of recanalization and a high mortality rate for this condition have been noted, even with endovascular treatment.

METHODS

We report the results of emergency embolectomy in six patients with acute embolic occlusion of the internal carotid artery (ICA) bifurcation. All six patients were admitted to our institute within 2 h of the onset of symptoms. Computed tomography (CT) scans on admission revealed no low-density or high-density regions in any patients. The time between onset of symptoms and completion of angiography ranged from 2 to 4 h (2.8 +/- 0.7 h).

RESULTS

Emergency embolectomy was performed for each patient. Recanalization was confirmed angiographically in four of the patients. In the remaining two patients, massive infarction in the territory of the ICA was detected on the CT scans obtained the day of the operation, and postoperative angiography was not performed in these two cases. These two patients died of uncal herniation 6 days after onset. Two of the six patients were able to walk with a cane 2 months after surgery. The remaining two patients were unable to walk or attend to their own bodily needs without assistance. The time elapsed between onset of symptoms to reopening of the occluded vessel was within 6 h in the four surviving patients. The recanalization rate was 66.7% (4/6) for the embolectomy procedure, significantly higher than that (12.5%) of the thrombolytic therapy reported in a previous study.

CONCLUSIONS

In summary, open embolectomy can be performed when the time after onset of symptoms is less than 6 h.

The simple indicator for revascularization of acute middle cerebral artery occlusion using angiogram and ultra-early embolectomy

BACKGROUND

The purpose of the study was: (1) to find a clinical indicator for revascularization of acute middle cerebral artery (MCA) occlusion using angiograms of 100 patients examined immediately after onset and treated medically and (2) to investigate 10 ultra-early MCA embolectomies.

METHODS

Quantity of collateral circulation, based on time required for conduction of contrast media to the insular portion of the MCA from the anterior cerebral artery, MCA conduction time (MCT) was graded as: Grade 1: In the arterial phase, there was conduction not only to the insular portion of the MCA but also to proximal M2; Grade 2: Conduction to the insular portion was present in late arterial phase; Grade 3: Conduction was present in capillary phase; Grade 4: Conduction was present in venous phase; Grade 5: No conduction was seen. The results of embolectomy are discussed.

RESULTS

MCT can predict the extent of resultant low-density area on computed tomographic scan. For Grades 3, 4, or 5, embolectomy could be considered superior to medical treatment, if the low-density area was localized in the basal ganglia or centrum semiovale after surgery. Consequently, embolectomy was effective in four cases recanalized within 6 hours of onset. Except for one Grade 5 case, the remaining nine cases showed neither lethal hemorrhagic infarction nor brain edema. Overall outcome was significantly better than cases treated medically (p < 0.05), but some cases did not recover from hemiparesis due to infarcts in the area of the lenticulostriate arteries.

CONCLUSIONS

MCT helps to predict the applicability of revascularization of acute MCA occlusion. Efficacy of embolectomy depends on revascularization within 6 hours of onset. Even after complete MCA flow restoration, infarcts in the area of the lenticulostriate arteries cannot always be prevented.

Carotid endarterectomy and intracranial thrombolysis: simultaneous and staged procedures in ischemic stroke

PURPOSE

The feasibility and safety of combining carotid surgery and thrombolysis for occlusions of the internal carotid artery (ICA) and the middle cerebral artery (MCA), either as a simultaneous or as a staged procedure in acute ischemic strokes, was studied.

METHODS

A nonrandomized clinical pilot study, which included patients who had severe hemispheric carotid-related ischemic strokes and acute occlusions of the MCA, was performed between January 1994 and January 1998. Exclusion criteria were cerebral coma and major infarction established by means of cerebral computed tomography scan. Clinical outcome was assessed with the modified Rankin scale.

RESULTS

Carotid reconstruction and thrombolysis was performed in 14 of 845 patients (1.7%). The ICA was occluded in 11 patients; occlusions of the MCA (mainstem/major branches/distal branch) or the anterior cerebral artery (ACA) were found in 14 patients. In three of the 14 patients, thrombolysis was performed first, followed by carotid enarterectomy (CEA) after clinical improvement (6 to 21 days). In 11 of 14 patients, 0.15 to 1 mIU urokinase was administered intraoperatively, ie, emergency CEA for acute ischemic stroke (n = 5) or surgical reexploration after elective CEA complicated by perioperative intracerebral embolism (n = 6). Thirteen of 14 intracranial embolic occlusions and 10 of 11 ICA occlusions were recanalized successfully (confirmed with angiography or transcranial Doppler studies). Four patients recovered completely (Rankin 0), six patients sustained a minor stroke (Rankin 2/3), two patients had a major stroke (Rankin 4/5), and two patients died. In one patient, hemorrhagic transformation of an ischemic infarction was detectable postoperatively.

CONCLUSION

Combining carotid surgery with thrombolysis (simultaneous or staged procedure) offers a new therapeutic approach in the emergency management of an acute carotid-related stroke. Its efficacy should be evaluated in interdisciplinary studies.

Interventional use of plasminogen activators in central nervous system diseases

Still an experimental approach, the direct intra-arterial infusion of plasminogen activators in the setting of acute thrombotic stroke has received impetus from successful clinical trials of intravenous infusion therapy. Direct therapy, employing catheter delivery, has successfully produced evidence of recanalization in carotid artery territory and vertebrobasilar artery territory thrombotic occlusions. One very recent prospective randomized study has demonstrated the success and limitations of this approach. Attention to safety concerns will be important to the future success of direct intra-arterial delivery of plasminogen activators in acute thrombotic stroke.

Intravenous thrombolytic therapy in acute stroke

The article reviews the experimental basis of thrombolytic therapy, and summarizes the results of the recent trials of thrombolysis. Five large clinical trails have evaluated intravenous thrombolytic therapy for the treatment of hyperacute (< 6 h) stroke. Three of these studies were negative, one was equivocal, and one was strongly positive. The failure of demonstrate efficacy definitively in four of these trials may be related to a number of methodological factors, including the type and dose of drug administered, the timing of drug administered, and the method of patient selection for treatment. The NINDS recombinant tissue plasminogen activator (rt-PA) study showed that thrombolytic therapy can be of substantial benefit when administered within 3 h of stroke onset using strict patient selection criteria and rt-PA is now FDA approved for treatment of acute stroke. However, the risk of clinically significant bleeding is elevated. To achieve the favorable risk/benefit ratio demonstrated in the NINDS trial, patients must be screened by experienced clinicians for contraindications to thrombolysis and the acute computerized tomography (CT) brain scan must be carefully evaluated for radiographic features that increase the risk of cerebral hemorrhage. Guidelines for the use of rt-PA are provided, as well as insights into future thrombolytic treatment strategies.

Practice guidelines: a more rational approach to diagnosis and treatment and a more effective use of health care resources

Practice guidelines are systematically developed statements to assist practitioner and patient decisions about appropriate health care for specific clinical circumstances. The implementation of practice guidelines is justified by factors such as variations in clinical practice, malpractice and its associated costs, and the need to contain health care expenditures. In this context, practice guidelines promote a more rational approach to clinical decision making and better quality of care. Although there are several limitations to the use of guidelines in current practice, different organizations (professional societies, government agencies, licensing authorities, educational institutions) have a potential interest in their development. A working group on the development of practice guidelines endorsed by the Italian Society of Neurology has been active since 1995. The aims of this group include the development of guidelines to be accepted by the medical community and to be placed within the framework of initiatives of the Italian Ministry of Health.