Asymptomatic hemorrhagic transformation of cerebral infarction does not worsen long-term outcome

Asymptomatic parenchymal haemorrhage following endovascular treatment: Impact on functional outcome in patients with acute ischaemic stroke

BACKGROUND AND PURPOSE

In patients with acute ischaemic stroke (AIS), haemorrhagic transformation (HT) following endovascular treatment (EVT) is associated with poor functional outcome. However, the impact of asymptomatic HT, not linked to neurological deterioration in the acute phase, is unknown. We aimed to investigate the impact of asymptomatic PH1 (aPH1) and PH2 (aPH2) subtypes of HT on the functional outcome of patients treated with EVT.

METHODS

We conducted a retrospective study of patients with AIS who were consecutively admitted to our comprehensive stroke centre between January 2019 and December 2022, and who underwent EVT. We collected clinical, radiological, and procedural data. HTs were categorized according to the Heidelberg classification. The primary outcome was the shift on the modified Rankin Scale (mRS) at 3 months of follow-up. We performed bivariate and multivariable ordinal regression analyses to test the association between aPH1/aPH2 and the primary outcome.

RESULTS

We included 314 patients (mean age = 72.5 years [SD = 13.6], 171 [54.5%] women). We detected 54 (17.2%) patients with HT; 23 (7.3%) were classified as PH2 (11 asymptomatic) and 17 (5.4%) as PH1 (16 asymptomatic). The adjusted common odds ratio for aPH2 of worsening 1 point on the 3-month mRS was 3.32 (95% confidence interval = 1.16-9.57, p = 0.026). No association was observed for aPH1. aPH2 was also independently associated with lower odds of achieving a favourable outcome (mRS = 0-2). Neither aPH1 nor aPH2 was associated with mortality.

CONCLUSIONS

In patients with AIS treated with EVT, aPH2 is independently associated with unfavourable functional outcome.

Prognosis associated with asymptomatic intracranial hemorrhage after acute ischemic stroke: a systematic review and meta-analysis

BACKGROUND AND PURPOSE

It remains inconclusive whether asymptomatic intracranial hemorrhage (aICH) after acute ischemic stroke is innocuous. We aimed to conduct a meta-analysis assessing the relationship between the aICH and poor neurological outcomes.

METHODS

We searched PubMed, EMBASE and Web of Science from their inception to 30 November 2021 and performed a meta-analysis on the association between the aICH and neurological prognosis after acute ischemic stroke at 3 months, including poor outcomes (modified Rankin Scale [mRS] score ≥ 2 or mRS ≥ 3) and mortality.

RESULTS

Fourteen studies were included in the analysis, reporting on a total of 10,915 participants after acute ischemic stroke. The risks of poor outcome (mRS ≥ 2 or mRS ≥ 3) in patients with aICH were significantly higher than patients without ICH (OR 1.70, 95% CI 1.33-2.18; OR 1.43, 95% CI 1.20-1.70, respectively), based on adjusted data. The difference between the two groups was not significant for mortality. The results of subgroup analysis showed aICH were associated with higher ratio of mild poor prognosis (mRS ≥ 2) (OR 1.59, 95% CI 1.11-2.27), but it had no association with functional dependence (mRS ≥ 3) after recanalization. No significant influence of aICH on poor outcome (mRS ≥ 3) was found in non-recanalization group. Further stratified analysis revealed that only aICH with patients receiving endovascular therapy (EVT) could increase the risk of mild poor prognosis (mRS ≥ 2) at 3 months.

CONCLUSIONS

Our results indicate that compared with patients without ICH, those who developed aICH during the acute stage of ischemic stroke had an increasing risk of worse outcome, especially in patients with endovascular therapy.

Extent of white matter lesion is associated with early hemorrhagic transformation in acute ischemic stroke related to atrial fibrillation

BACKGROUND

Hemorrhagic transformation (HT) after stroke, related to atrial fibrillation (AF), is a frequent complication, and it can be associated with a delay in the (re-)initiation of oral anticoagulation therapy. We investigated the effect of the presence and severity of white matter disease (WMD) on early HT after stroke related to AF.

METHODS

A consecutive series of patients with recent (<4 weeks) ischemic stroke and AF, treated at the Hyper Acute Stroke Unit of the Imperial College London between 2010 and 2017, were enrolled. Patients with brain MRI performed 24-72 h from stroke onset and not yet started on anticoagulant treatment were included. WMD was graded using the Fazekas score.

RESULTS

Among the 441 patients eligible for the analysis, 91 (20.6%) had any HT. Patients with and without HT showed similar clinical characteristics. Patients with HT had a larger diffusion-weighted imaging (DWI) infarct volume compared to patients without HT (p < .001) and significant difference in the distribution of the Fazekas score (p = .001). On multivariable analysis, HT was independently associated with increasing DWI infarct volume (odd ratio (OR), 1.03; 95% confidence interval (CI), 1.01-1.05; p < .001), higher Fazekas scores (OR, 1.94; 95% CI, 1.47-2.57; p < .001) and history of previous intracranial hemorrhage (OR, 4.80; 95% CI, 1.11-20.80; p = .036).

CONCLUSIONS

Presence and severity of WMD is associated with increased risk of development of early HT in patients with stroke and AF. Further evidence is needed to provide reliable radiological predictors of the risk of HT in cardioembolic stroke.

Efficacy and safety of sonothrombolysis in patients with acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Accumulating clinical evidence has indicated that sonothrombolysis can aid in the treatment of ischemic stroke; however, these findings remain controversial. The purpose of the present meta-analysis was to assess randomized clinical studies concerning the effects of sonothrombolysis on ischemic stroke to evaluate its safety and efficacy.

METHODS

We systematically searched the Cochrane Library, PubMed, and EMBASE databases for literature published between the inception of electronic data and May 2019 regarding sonothrombolysis for acute ischemic stroke. Only randomized controlled trials were included. Data extraction was based on patient characteristics, ultrasound variables (any duration or frequency, without microbubble), and outcome variables (safety and efficacy).

RESULTS

Five trials were included in the present study. Clinical functional recovery was evaluated at different time points (several days or 3 months), and heterogeneity was low. Sonothrombolysis did not lead to an increase in symptomatic intracranial hemorrhagic complications or death. Our results demonstrated that patients treated with sonothrombolysis had significantly higher rates of recanalization and asymptomatic intracerebral hemorrhage than patients treated with intravenous thrombolysis alone. In the subgroup of middle cerebral artery (MCA) occlusion patients, sonothrombolysis was found to greatly increase the efficacy outcomes compared to intravenous thrombolysis.

CONCLUSIONS

Evidence suggests that sonothrombolysis is a technically feasible and potentially effective treatment that has beneficial effects on recanalization and increases the rate of asymptomatic intracerebral hemorrhage in stroke patients. Additionally, short- and long-term clinical outcome analyses were improved in the MCA occlusion sonothrombolysis subgroup. Larger clinical trials of MCA occlusion patients are necessary to verify these findings.

Haemorrhagic transformation in ischaemic stroke is more frequent than clinically suspected - A neuropathological study

OBJECTIVES

The vast majority of literature on the frequency of the haemorrhagic transformation of ischaemic stroke is based on imaging studies. The purpose of the present study was to assess the added value of autopsy and neuropathological analysis in a neurology centre with emphasis on acute stroke care.

METHODS

We retrospectively analysed the findings of 100 consecutive brain autopsies followed by detailed clinical correlation.

RESULTS

The clinical diagnosis was confirmed by neuropathology in every patient with intracerebral haemorrhage and with non-cerebrovascular neurological disorders (e.g. primary tumours, metastases, infections). At admission 64 patients (age 62years, SD 6.5) were diagnosed with acute ischaemic stroke. In 10 of these patients (16%) haemorrhagic transformation was diagnosed clinically by a second CT. In 24 cases (38%) haemorrhagic transformation was detected only at autopsy. The distribution of haemorrhagic transformation in our material was the following: small petechiae in 26.5%, more confluent petechiae in 29.4%, ≤30% of the infarcted area with some mild space-occupying effect in 29.4% and >30% of the infarcted area with significant space-occupying effect or clot remote from infarcted area in 14.7%. Most of the PH1-2 transformations developed in thrombolysed patients and all of the PH2 type transformations were diagnosed already clinically.

CONCLUSIONS

We demonstrated that haemorrhagic transformation is frequent and often undiscovered in vivo. Our findings underline the importance of post-mortem neuropathological examination also in the era of advanced imaging techniques and prove that autopsy is the ultimate yardstick of our diagnostic and therapeutic efforts. The high number of haemorrhagic transformations diagnosed only after death is an important novel finding with clinical implications.

Thrombolytic-Related Asymptomatic Hemorrhagic Transformation Does Not Deteriorate Clinical Outcome: Data from TIMS in China

OBJECTIVE

It has been unclear whether thrombolytic-related asymptomatic hemorrhagic transformation (AHT) affects the clinical outcome. To answer this question, we examined whether thrombolytic-related AHT affect short-term and long-term clinical outcome.

METHODS

All data were collected from the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China (TIMS-China) registry. The patients were diagnosed as having AHT group and non- hemorrhagic transformation (HT) group based on clinical and imaging data. The patients with symptomatic hemorrhagic transformation were excluded from this study. Thrombolytic-related AHT was defined according to European-Australasian Acute Stroke Study (ECASS) II criteria. 90-day functional outcome, 7-day National Institutes of Health Stroke Scale (NIHSS) score, 7-day and 90-day mortalities were compared between two groups. Logistic regression analysis was used to evaluate the effects of AHT on a short-term and long-term clinical outcome.

RESULTS

904 of all 1440 patients in TIMS-China registry were enrolled. 89 (9.6%) patients presented with AHT after thrombolysis within 24-36 h. These patients with AHT were more likely to be elder age, cardioembolic subtype, and to have higher National Institutes of Health Stroke Scale score before thrombolysis than patients without AHT. No significant difference was found on the odds of 7-day (95% CI:0.692 (0.218-2.195), (P = 0.532) or 90-day mortalities (95% CI:0.548 (0.237-1.268), P = 0.160) and modified Rankin Score(0-1) at 90-day (95% CI:0.798 (0.460-1.386), P = 0.423) or modified Rankin Score(0-2) at 90-day (95% CI:0.732 (0.429-1.253), P = 0.116) or modified Rankin Score(5-6) at 90-day (95% CI:0.375 (0.169-1.830), P = 0.116) between two groups.

CONCLUSIONS

Thrombolytic-related AHT does not deteriorate short-term and long-term clinical outcome.

Postthrombolytic Antiplatelet Use for Patients with Intercerebral Hemorrhage without Extensive Parenchymal Involvement Does Not Worsen Outcome

Background and Purpose

It is unclear whether postthrombolytic antiplatelet (AP) therapy after thrombolytic-related hemorrhage without extensive parenchymal involvement (THEPI) affects the clinical outcome. This study explored whether AP administration in patients with THEPI affects short- and long-term outcomes.

Methods

All of the data for this study were collected from the Thrombolysis Implementation and Monitor of Acute Ischemic Stroke in China (TIMS-China) registry. Patients with THEPI were assigned to either the AP (AP therapy should be commenced 24 h after intravenous thrombolysis) or AP-naïve groups. THEPI was defined according to European-Australasian Acute Stroke Study II criteria. The 90-day functional outcome, 7-day National Institutes of Health Stroke Scale (NIHSS) score, and 7-day and 90-day mortalities were compared between the AP and AP-naïve groups. Logistic regression analysis was used to evaluate the effects of AP therapy on the short- and long-term clinical outcomes.

Results

Of the 928 patients enrolled from those in the TIMS-China registry (n=1,440), 89 (9.6%) had nonsymptomatic intracerebral hemorrhage (ICH) within 24-36 h after thrombolysis; 33 (37%) of these patients were given AP therapy (AP group) and 56 (63%) were not (AP-naïve group). No significant differences were found for the risk of 7-day aggravated ICH (p=0.998), 7-day NIHSS score (p=0.5491), 7-day mortality [odds ratio (OR)=3.427; 95% confidence interval (95% CI)=0.344-34.160; p=0.294], 90-day mortality (OR=0.788, 95% CI=0.154-4.040, p=0.775), or modified Rankin score 5 or 6 at 90-days (OR=1.108, 95% CI=0.249-4.928, p=0.893) between the AP and AP-naïve groups after THEPI.

Conclusions

Early administration of postthrombolytic AP therapy after THEPI does not worsen either the short- or long-term outcome. AP therapy may be a reasonable treatment option for patients with THEPI to reduce the risk of ischemic stroke recurrence.

Thyroid hemorrhage causing airway obstruction after intravenous thrombolysis for acute ischemic stroke

BACKGROUND

There are several life-threatening complications associated with intravenous thrombolysis after acute ischemic stroke such as symptomatic intracerebral hemorrhage, orolingual angioedema, or less frequent, bleedings of the mucosa or ecchymosis. Aside from these known critical incidents, rare and unfamiliar complications may be even more challenging, as they are unexpected and may mimic events that appear more frequently. We report a rare and unusual acute complication of intravenous thrombolysis with recombinant tissue plasminogen activator (rt-PA) (0.9 mg/kg) administered for acute ischemic stroke.

METHODS

Medical records, radiologic imaging, and pathologic specimens were reviewed.

RESULTS

A 86-year-old woman developed acute respiratory failure 20 h after thrombolysis with suspected angioedema triggered by intravenous rt-PA. The inspiratory stridor and dyspnea were unresponsive to bronchodilators, corticosteroids, and inhaled adrenaline. After endotracheal intubation, laryngoscopy showed no significant supraglottic narrowing. Thyroidal sonography and cervical computed tomography revealed a thyroidal mass causing a tracheal and vascular compression compatible with thyroidal hemorrhage. Sonography showed a nodular goiter of the right thyroid gland. A total thyroidectomy was performed and histologic analysis confirmed a hemorrhage of the right thyroidal lobe.

CONCLUSIONS

Acute airway obstruction with respiratory failure due to thyroidal hemorrhage after intravenous thrombolysis is an important life-threatening complication, mimicking an anaphylactic reaction or a more frequent orolingual angioedema.

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.

Predictors and clinical relevance of hemorrhagic transformation after endovascular therapy for anterior circulation large vessel occlusion strokes: a multicenter retrospective analysis of 1122 patients

BACKGROUND AND PURPOSE

Endovascular techniques are frequently employed to treat large artery occlusion in acute ischemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial hemorrhage (ICH) after endovascular therapy.

METHODS

Retrospective analysis of consecutive patients presenting to 13 high volume stroke centers with AIS due to proximal occlusion in the anterior circulation who underwent endovascular treatment within 8 h from symptom onset. Logistic regression was performed to determine the variables associated with ICH, hemorrhagic infarction (HI), and parenchymal hematomas (PHs), as well as 90 day poor outcome (modified Rankin Scale score ≥3) and mortality.

RESULTS

There were a total of 363 ICHs (overall rate 32.3%; HI=267, 24%; PH=96, 8.5%) among the 1122 study patients (mean age 67±15 years; median National Institutes of Health Stroke Scale score 17 (IQR 13-20)). Independent predictors for HI included diabetes mellitus (OR 2.27, 95% CI (1.58 to 3.26), p<0.0001), preprocedure IV tissue plasminogen activator (tPA) (1.43 (1.03 to 2.08), p<0.037), Merci thrombectomy (1.47 (1.02 to 2.12), p<0.032), and longer time to puncture (1.001 (1.00 to 1.002), p<0.026). Patients with atrial fibrillation (1.61 (1.01 to 2.55), p<0.045) had a higher risk of PH while the use of IA tPA (0.57 (0.35 to 0.90), p<0.008) was associated with lower chances of PH. Both the presence of HI (2.23 (1.53 to 3.25), p<0.0001) and PH (6.24 (3.06 to 12.75), p<0.0001) were associated with poor functional outcomes; however, only PH was associated with higher mortality (3.53 (2.19 to 5.68), p<0.0001).

CONCLUSIONS

Greater understanding about the predictors and consequences of ICH post endovascular stroke therapy is essential to improve risk assessment, patient selection/clinical outcomes, and early prognostication. Our data suggest that patients with atrial fibrillation are particularly prone to severe ICH and question the 'benign' nature of HI suggested by earlier studies.

Asymptomatic Hemorrhagic Transformation of Infarction and Its Relationship With Functional Outcome and Stroke Subtype

Background and Purpose— Asymptomatic hemorrhagic transformation of infarction (AHTI) is common, but its risk factors and relationship with functional outcome are poorly defined.

Methods— The analyses used data from the Tinzapararin in Acute Ischaemic Stroke Trial, a randomized controlled trial assessing tinzaparin (low molecular weight heparin) versus aspirin in 1484 patients with acute ischemic stroke. CT head scans (baseline, day 10) were adjudicated for the presence of hemorrhagic transformation. Stroke subtype was classified according to modified Trial of Org 10172 in Acute Stroke Treatment (small vessel, large vessel, cardioembolic) and the Oxfordshire Community Stroke Project (total anterior, partial anterior, lacunar, and posterior circulatory syndromes). Modified Rankin scale and Barthel Index were measured at 3 and 6 months. Analyses were adjusted for age, sex, severity, blood pressure, infarct volume, and treatment. Symptomatic hemorrhage was excluded.

Results— At day 10, AHTI did not differ between aspirin (300 mg; 32.8%) and medium-dose (100 IU/kg; 36.0%) and high-dose (175 IU/kg; 31.4%) tinzaparin groups ( P =0.44). Relative to lacunar stroke, AHTI on follow-up CT was significantly increased in total anterior circulation syndrome (odds ratio, 11.5; 95% CI, 7.1 to 18.7) and partial anterior circulation syndrome (odds ratio, 7.2; 95% CI, 4.5 to 11.4) stroke. Similarly, relative to small vessel disease, AHTI was increased in large vessel (odds ratio, 15.1; 95% CI, 9.4 to 24.3) and cardioembolic (odds ratio, 14.1; 95% CI, 8.5 to 23.5) stroke. After adjustment for infarct volume, the presence of AHTI was not associated with outcome at 3 or 6 months as measured by the modified Rankin Scale and Barthel Index.

Conclusions— AHTI is increased in ischemic stroke with cortical syndromes and of large vessel or cardioembolic etiology. Heparin does not increase AHTI. AHTI is not associated with functional outcome.

Management of thrombolysis-associated symptomatic intracerebral hemorrhage

BACKGROUND

Symptomatic intracerebral hemorrhage (sICH) is the most devastating complication of thrombolytic therapy for acute stroke. It is not clear whether patients with sICH continue to bleed after diagnosis, nor has the most appropriate treatment been determined.

METHODS

We performed a retrospective analysis of our prospectively collected Get With the Guidelines-Stroke database between April 1, 2003, and December 31, 2007. Radiologic images and all procoagulant agents used were reviewed. Multivariable logistic regression was performed to identify factors associated with in-hospital mortality.

RESULTS

Of 2362 patients with acute ischemic stroke during the study period, sICH occurred in 19 of the 311 patients (6.1%) who received intravenous tissue plasminogen activator and 2 of the 72 (2.8%) who received intra-arterial thrombolysis. In-hospital mortality was significantly higher in patients with sICH than in those without (15 of 20 [75.0]% vs 56 of 332 [16.9%], P < .001). Eleven of 20 patients (55.0%) received therapy for coagulopathy: 7 received fresh frozen plasma; 5, cryoprecipitate; 4, phytonadione (vitamin K(1)); 3, platelets; and 1, aminocaproic acid. Independent predictors of in-hospital mortality included sICH (odds ratio, 32.6; 95% confidence interval, 8.8-120.2), increasing National Institutes of Health Stroke Scale score (1.2; 1.1-1.2), older age (1.3; 1.0-1.7), and intra-arterial thrombolysis (2.9; 1.4-6.0). Treatment for coagulopathy was not associated with outcome. Continued bleeding (>33% increase in intracerebral hemorrhage volume) occurred in 4 of 10 patients with follow-up scans available (40.0%).

CONCLUSIONS

In many patients with sICH after thrombolysis, coagulopathy goes untreated. Our finding of continued bleeding after diagnosis in 40.0% of patients suggests a powerful opportunity for intervention. A multicenter registry to analyze management of thrombolysis-associated intracerebral hemorrhage and outcomes is warranted.

Neurological Outcomes in Patients With Ischemic Stroke Receiving Enoxaparin or Heparin for Venous Thromboembolism Prophylaxis

Background and Purpose— The Prevention of VTE after Acute Ischemic Stroke with LMWH (PREVAIL) study demonstrated that enoxaparin was superior to unfractionated heparin (UFH) in preventing venous thromboembolism in patients with ischemic stroke and was associated with a small but statistically significant increase in extracranial hemorrhage rates. In this PREVAIL subanalysis, we evaluate the long-term neurological outcomes associated with the use of enoxaparin compared with UFH. We also determine predictors of stroke progression.

Methods— Acute ischemic stroke patients aged ≥18 years, who could not walk unassisted, were randomized to receive enoxaparin (40 mg once daily) or UFH (5000 U every 12 hours) for 10 days. Patients were stratified according to baseline stroke severity using the National Institutes of Health Stroke Scale score. End points for this analysis included stroke progression (≥4-point increase in National Institutes of Health Stroke Scale score), neurological outcomes up to 3 months postrandomization (assessed using National Institutes of Health Stroke Scale score and modified Rankin Scale score), and incidence of intracranial hemorrhage.

Results— Stroke progression occurred in 45 of 877 (5.1%) patients in the enoxaparin group and 42 of 872 (4.8%) of those receiving UFH. Similar improvements in National Institutes of Health Stroke Scale and modified Rankin Scale scores were observed in both groups over the 90-day follow-up period. Incidence of intracranial hemorrhage was comparable between groups (20 of 877 [2.3%] and 22 of 872 [2.5%] in enoxaparin and UFH groups, respectively). Baseline National Institutes of Health Stroke Scale score, hyperlipidemia, and Hispanic ethnicity were independent predictors of stroke progression.

Conclusions— The clinical benefits associated with use of enoxaparin for venous thromboembolism prophylaxis in patients with acute ischemic stroke are not associated with poorer long-term neurological outcomes or increased rates of symptomatic intracranial hemorrhage compared with UFH.

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.

Intracranial Hemorrhage Associated With Revascularization Therapies

Background and Purpose— This review discusses the state of our current knowledge on hemorrhagic transformation (HT) and summarizes key factors to be considered when comparing risk associated with various approaches to revascularization.

Summary of Review— HT is a common and natural consequence of infarction, likely related to matrix metalloproteinases and free radical pathways disrupting permeability barriers between blood and brain during ischemia and reperfusion. Symptomatic HT rates within 24 to 36 hours of stroke are increased in the setting of revascularization therapy regardless of modality. HT incidence rates must be considered in the context of the timing of imaging, the period of the study, the definition of clinically significant HT, and other key predictors of HT. The most consistently identified predictors of clinically significant HT in acute revascularization trials have been thrombolytic therapy, dose of lytic agents, edema or mass effect on head CT, stroke severity, and age. Other risk factors may be hyperglycemia, concurrent heparin use, timing of therapy, and timing of successful recanalization. Future predictors may also include imaging parameters, serological markers, variables related to intra-arterial technique, and arterial lesion location.

Conclusions— Understanding how baseline and treatment variables impact HT rates after acute stroke is critical for those designing and interpreting acute stroke trials. Future trials should consider the use of PH-2 as a standardized safety end point, putting hemorrhagic changes in the context of overall clinical outcome, and developing strategies to reduce the rates of clinically significant intracranial hemorrhage.