By providing estimates on the benefits and harms of treating patients with acute ischaemic stroke outside the current approvals, the results of a study published on May 23 in The Lancet, "enables clinicians to consider thrombolytic treatment for a wider range of patients, especially those older than 80 years of age." The third International Stroke Trial (IST-3) suggests that recombinant tissue plasminogen activator (rt-PA) improved functional outcome. "The data reinforce the need for further efforts to increase the proportion of all ischaemic strokes treated within three hours,” researchers said. “The additional data from IST-3 give greater confidence that mortality is not increased by treatment. The implications for ongoing research are that the data strengthen the rationale for the ongoing trials of thrombolysis in patients presenting more than 4.5 hours after onset of stroke, and suggest that the imposition of upper age limits on future trials in acute stroke will become harder to justify." |
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IST-3, which sought to determine whether a wider range of patients might benefit from intravenous thrombolytic therapy up to six hours from stroke onset, enrolled 3,035 patients from 156 hospitals in 12 countries. All of these patients were included in the analyses and slightly more than half (53%) were older than 80 years of age.
At six months, 554 (37%) patients in the rt-PA group versus 534 (35%) in the control group were alive and independent. More deaths occurred within seven days in the rt-PA group (163 [11%]) than in the control group (107 [7%], but between seven days and six months there were fewer deaths in the rt-PA group than in the control group. By six months, similar numbers, in total, had died (408 [27%] in the rt-PA group versus 407 [27%] in the control group.
"Our trial was underpowered to reliably detect important subgroup effects, and so a collaborative individual patient data meta-analysis (the Stroke Thrombolysis Trialists Collaboration [STTC]) has been established, which will include data from all the completed intravenous rt-PA trials and will update the previous pooled analysis," one researcher said. "The meta-analysis will explore which baseline factors, other than time, might modify the effects of treatment on major outcomes (such as death, functional outcome, and intracerebral haemorrhage), and so provide better guidance for clinicians and patients to apply this treatment as effectively as possible in routine practice."