David Brill
The window of opportunity for treating acute ischemic stroke (AIS) is set to widen, bringing hope to previously untreatable patients, a stroke expert said recently.
The recently published European Cooperative Acute Stroke Study (ECASS) III, showed that thrombolysis with alteplase can reduce the long-term disability risk, when given up to 4.5 hours after symptom onset.
Present guidelines limit the use of alteplase to a window of 3 hours post-stroke, but less than 2 percent of patients currently receive the treatment.
Dr. Lee Kim En, head of the department of neurology at the National Neuroscience Institute in Singapore, said at a recent press conference that the ECASS III data are convincing and it is "just a matter of time" until international approval is gained and guidelines adjusted accordingly.
"More patients will benefit from this extension of the window," he said, noting that treatment within 3 hours is typically very difficult to achieve since patients rarely arrive at hospital within this timeframe.
"Alteplase is the only proven therapy for AIS, which is why we are working very hard to extend the benefits to the other 98 percent of patients."
ECASS III randomized 821 AIS patients who presented during the extended post-stroke window to receive either alteplase or placebo. [N Engl J Med 2008 Sep 25;359(13):1317-29]
A favorable outcome at 90 days, as defined by a score of 0 or 1 on the modified Rankin scale for stroke disability, was reported for 52.4 percent of patients in the treatment group compared to 45.2 percent in the placebo group (odds ratio 1.34; P=0.04).
Alteplase increased the risk of intracranial hemorrhage, which affected 27 percent of patients in the treatment group compared with 17.6 percent in the placebo group (P=0.001). Mortality, however, was not significantly different between the groups, suggesting that the increased risk was outweighed by the overall benefits of treatment, according to Lee.
He added that it remains important to treat stroke as quickly as possible, and that the study findings should not be seen as an excuse to delay this process.
"Time is brain – every minute counts here. Having more time does not mean you can take more time… if you can give treatment within a minute of coming through the door that’s the best thing to do."
The new protocol is already being introduced at Tan Tock Seng Hospital, Singapore, which treats around 2,000 AIS patients each year. At present just 20 to 25 of these receive alteplase, Lee said.
While the hospital is working hard to accelerate its internal processing of AIS patients, increasing public awareness of stroke symptoms will also be an important step towards improving outcomes, he said.
In the event that a stroke patient presents to their GP, the physician can also help by documenting the time of symptom onset and sending them straight to hospital, he added.
ECASS III was conducted between July 2003 and February 2008 at 30 sites across 19 European countries. Alteplase was given intravenously at a dosage of 0.9 mg per kg. The trial was sponsored by Boehringer- Ingelheim, which manufactures the drug.
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