The annual scientific meeting of the Stroke Society of Australasia had a broad ranging program related to the many facets of stroke care, with a mix of invited speaker presentations and original papers. Over 240 registrants from a number of countries and range of disciplines involved in the care of stroke victims attended. Stroke remains a major cause of death and disability in both Western and developing countries. The burden of stroke will continue to rise due to the aging structure of society despite a fall in crude stroke incidence with time. A number of themes related to stroke care appeared through the course of the meeting including acute stroke care and therapy, stroke imaging, epidemiology of stroke, rehabilitation of stroke, and prevention of stroke and recurrent stroke.
Acute stroke therapy
A satellite meeting of the Australasian Stroke Unit Network dealt with strategies to maximize the use of thrombolysis in early acute ischemic stroke. Speakers emphasized the strength of the data relating to the efficacy of tissue plasminogen activator (TPA) use in the first 180 min after stroke onset based on the overview of the TPA trials including reanalysis of the National Institute of Neurological Diseases and Stroke trial. The importance of close liaison with ambulance teams and the emergency room to ensure early notification, and hence treatment of acute stroke victims, was emphasized. Nils Wahlgren -(University of Stockholm, Sweden) described the European experience in the use of TPA and introduced the Safe Implementation of Thrombolysis in Stroke registry, which aims to record data online relating to patients treated in routine clinical practice with TPA. This registry has been operating in Europe with over 2700 patients enrolled to date with extension to Australia and elsewhere planned.
In the main meeting, James Grotta (University of Texas, TX, USA) delivered a keynote lecture on Novel Therapies for Acute Stroke which outlined some techniques which may augment thrombolytic therapy to deliver a better outcome. Transcranial Doppler ultrasonography can be used to diagnose and follow occlusion of the middle cerebral artery in acute hemispheric ischemic stroke. Ongoing insonation after thrombolysis may also be therapeutic in that recanalization rates were improved significantly using this technique. The role of antiplatelet, anticoagulant, thrombin inhibitor and group IIb/IIIa receptor blockers to maintain recanalization remains contentious with potential bleeding side effects still a significant problem. A wide variety of neuroprotectants have been tested in humans at great financial cost without much therapeutic success, despite promising animal studies. Relatively simple therapies such as caffeine, ethanol and hypothermia have promising results in -animal models.
Joanna Wardlaw (University of Edinburgh, UK) presented detailed results from the Cochrane Collaboration -Overview of thrombolytic therapy in stroke emphasizing the paucity of data from randomized controlled trials concerning important patient subgroups. Significant questions remain concerning the risk versus benefit for thrombolytic therapy in the elderly, those with early infarct signs on computed tomography (CT), those between 3 and 6 h after stroke onset, those already taking antiplatelet therapy and those with lacunar stroke. Ongoing large clinical trials such as the International Stroke Trial III, European Cooperative Acute Stroke Study III and Epiphet may help to answer some of these questions.
A concurrent session was devoted to the management of primary intracerebral hemorrhage (PICH) which is responsible for 10–15% of strokes (more in an Asian population). Grotta presented an overview of the current treatment strategies in this difficult clinical problem. The natural history demonstrates that hemorrhages often enlarge in the first hours after onset resulting in clinical deterioration and sometimes death. Medical treatments such as free radical scavengers, thrombin inhibitors and induced hypothermia are helpful in animal models but require further testing in human populations. Surgical intervention to drain the hematoma appears helpful in cerebellar, subarachnoid and some lobar hemorrhages, although randomized trials of surgical versus medical therapy have been unable to establish clear superiority of either treatment modality. The role of blood pressure lowering acutely also remains unclear. Stephen Davis (Royal Melbourne Hospital/University of Melbourne, Victoria, Australia) presented preliminary data from the Novoseven trial of recombinant Factor VIIa in PICH, which demonstrated a reduction in hematoma growth with improved neurologic -outcome compared with placebo, but at the expense of an increase in thromboembolic events in the treated group compared with placebo. A larger randomized trial is needed to further define the risks and benefits of such therapy.
Stroke imaging
The better use of CT and magnetic resonance imaging (MRI) in the assessment of stroke was the subject of a further plenary lecture by Joanna Wardlaw. An early CT scan remains the gold standard in the assessment of acute stroke because of its availability, low cost and sensitivity in diagnosis of cerebral hemorrhage. The diagnosis of early infarct signs such as swelling, hypodensity and loss of gray–white matter differentiation remains problematic due to low inter- and intraobservor agreement. Despite these limitations, an early CT scan in acute stroke remains cost effective.
MRI imaging using different weighting techniques (i.e., diffusion and perfusion) may enable clearer definition of early infarct changes, although the relationship of these with clinical outcome is not exact. Up to 25% of stroke victims may be unable to tolerate an MRI scan due to technical and patient factors thus reducing its utility. Other speakers outlined the potential role of positron emission tomography scanning in studying metabolic and structural changes in acute stroke; a fluomisonidazole tracer may measure the ischemic penumbra around the core infarct.
Stroke epidemiology
A concurrent session was devoted to some of the less well-recognized risk factors for stroke with presentations related to variation in stroke rates within different ethnic groups and social classes. Within an Australian population, the risk of stroke is greater in certain ethnic groups and the socially disadvantaged despite adjustment for other known risk factor variances. Physical inactivity increases the relative risk of coronary heart disease twofold and probably has a similar effect on the relative risk of stroke. Activity levels are notoriously difficult to measure and the use of a pedometer to measure the number of steps taken daily may be a simple but valid tool. Smoking (both active and passive) has a clear dose-related relationship with the risk of stroke, although this is less clear for PICH. Binge alcohol drinking has a temporal relationship to stroke onset especially in the younger age group. A J-shaped relationship has been demonstrated in a number of studies between total alcohol consumption and stroke risk, with both abstinence and excess intake both increasing the risk compared with modest intake. The -population attributable risk of some of these lesser-known risk factors may still be very significant: smoking 22%, binge drinking 2% and physical inactivity 15%. Lifestyle modification remains a very worthwhile activity in stroke prevention.
Stroke therapy & rehabilitation
Invited speakers presented data relating to the role of supplemental nutrition in improving outcome after stroke with important data from the Feed or Ordinary Diet trial failing to demonstrate a better outcome in patients randomized to be given nutritional supplements, early nasogastric feeding or given percutaneous enterogastrostomy feeding tubes compared with nasogastric feeding tubes. The role of aphasia therapy and the use of very early mobilization (<24 h) after stroke onset to improve outcome was also reviewed. A large number of free communications also addressed research in this area. The meeting closed with a humorous, yet educational debate as to the merits of rehabilitation compared with acute stroke therapy in improving outcome after stroke. There was a consensus that stroke units, which encompass a multidisciplinary team, involved in acute evaluation, therapy and rehabilitation of stroke patients are essential to improve the outcome after stroke and should be developed in all hospitals treating over 100 stroke victims annually.