Dichotomized efficacy end points and global end-point analysis applied to the ECASS intention-to-treat data set: post hoc analysis of ECASS I

Alternative strategies for stroke care: a prospective randomised controlled trial

BACKGROUND

Organised specialist care for stroke improves outcome, but the merits of different methods of organisation are in doubt. This study compares the efficacy of stroke unit with stroke team or domiciliary care.

METHODS

A single-blind, randomised, controlled trial was undertaken in 457 acute-stroke patients (average age 76 years, 48% women) randomly assigned to stroke unit, general wards with stroke team support, or domiciliary stroke care, within 72 h of stroke onset. Outcome was assessed at 3, 6, and 12 months. The primary outcome measure was death or institutionalisation at 12 months. Analyses were by intention to treat.

FINDINGS

152 patients were allocated to the stroke unit, 152 to stroke team, and 153 to domiciliary stroke care. 51 (34%) patients in the domiciliary group were admitted to hospital after randomisation. Mortality or institutionalisation at 1 year were lower in patients on a stroke unit than for those receiving care from a stroke team (21/152 [14%] vs 45/149 [30%]; p<0.001) or domiciliary care (21/152 [14%] vs 34/144 [24%]; p=0.03), mainly as a result of reduction in mortality. The proportion of patients alive without severe disability at 1 year was also significantly higher on the stroke unit compared with stroke team (129/152 [85%] vs 99/149 [66%]; p<0.001) or domiciliary care (129/152 [85%] vs 102/144 [71%]; p=0.002). These differences were present at 3 and 6 months after stroke.

INTERPRETATION

Stroke units are more effective than a specialist stroke team or specialist domiciliary care in reducing mortality, institutionalisation, and dependence after stroke.

Acute ischemic stroke management

The use of thrombolytic therapy represents one of many recent developments in the management of acute ischemic stroke. The development of stroke teams and protocols has been driven by these new demands for an urgent response to ischemic stroke. The short time window of 3 hours for therapy with intravenous recombinant tissue plasminogen activator requires efficient evaluation and treatment of stroke patients and also necessitates a rigorous approach to blood pressure management, electrolytes, fluids, and temperature. Anticoagulation has not been proven to safely prevent progression or early recurrence of stroke, but antiplatelet therapy is worthwhile.

Acute ischemic stroke therapy

Acute ischemic stroke is a medical emergency that requires rapid evaluation and treatment. Prehospital and emergency department care can be streamlined to meet those goals. Intravenous rt-PA therapy improves outcome in selected patients with ischemic stroke if given within 3 hours of stroke onset, but offers no benefit beyond that time window. Intra-arterial thrombolytic therapy and intravenous defibrogenating agents may also be beneficial in selected patients. Newer thrombolytic agents such as aspirin and heparin in acute ischemic stroke treatment have been clarified by recent trials.

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.

Voxel-based mapping of irreversible ischaemic damage with PET in acute stroke

Objective mapping of irreversible tissue damage in the acute stage of ischaemic stroke would be useful for prognosis and in assessing the efficacy of therapeutic manoeuvres in impeding extension of infarction. From our database of 30 patients studied with 15O-PET within 5-18 h after onset of first-ever middle cerebral artery territory stroke, we extracted a subgroup of 19 survivors (age 74.6 +/- 8.5 years) in whom late CT coregistered with PET was available to determine final infarct topography. By means of a voxel-based analysis of the PET data, we determined putative thresholds for irreversible tissue damage as the lower limit of the 95% confidence interval calculated from all voxels within the ultimately non-infarcted brain parenchyma ipsilateral to the insult. The following values were found: 8.43 ml/100 ml/min, 0.87 ml/100 ml/min, 1.64 ml/100 ml, 0.27 and 2.21/min, for cerebral blood flow (CBF), oxygen consumption (CMRO2), blood volume (CBV), oxygen extraction fraction and the ratio CBF : CBV, respectively. Voxels below these thresholds occurred significantly more frequently in the final infarct region than in the non-infarcted parenchyma for CBF and CMRO2 (P = 0.016 and P = 0.0045, respectively, Wilcoxon test), but not for the other PET variables. Furthermore, with both CBF and CMRO2, the percentage of irreversible tissue damage voxels in the affected hemisphere relative to the opposite hemisphere was significantly positively correlated to both the volume of final infarct and the neurological outcome at 2 months (all P < 0.005, Spearman ranked test). These findings validate our voxel-based CBF and CMRO2 thresholds for probabilistic mapping of irreversible tissue damage within the 5-18 h interval after stroke onset; however, whether they would be applicable to earlier intervals remains to be determined. Transfer of our procedure for determination of irreversible tissue damage thresholds to other imaging modalities such as single proton emission computed tomography and diffusion-weighted MRI should be straightforward.

Thrombolysis for acute stroke

Thrombolysis for acute stroke is effective if administered according to the approved protocol. Since the initial report of success in 1995, a number of subsequent reports confirmed the safety and efficacy of this treatment. There is no particular subgroup of patients at increased likelihood of benefit or hemorrhage that can be identified at baseline. Unlike many expensive therapies, thrombolysis for acute stroke saves the health care system considerable long-term costs. The search for even safer and more effective thrombolytics continues.