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DOCTORS who use thrombolysis to treat acute ischaemic stroke in very elderly patients may be reassured by a new study that finds it is effective, but definitive results will only come from clinical trials, according to Australian neurologists.
They were commenting on a registry analysis study in the BMJ of almost 30 000 patients, which found that stroke patients given intravenous recombinant tissue plasminogen activator (IV rt-PA) had better functional outcomes than untreated patients, and those aged over 80 had similar benefits to younger patients.(1)
“Furthermore there are reassuring safety data on the risk of intracerebral haemorrhage,” the authors said. “Age alone should not be a barrier to treatment.”
Professor Graeme Hankey, consultant neurologist and head of the stroke unit at Royal Perth Hospital, said while the results were encouraging, they were certainly not proof the treatment was safe and effective in elderly people.
“The results provide reassurance that in a large population of elderly people, the treatment can be given pretty safely with no significantly greater risk,” he said.
“The real risk–benefit ratio will not be known until the results of ongoing randomised controlled trials like IST-3 are known.”(2)
The International Stroke Trial-3 is a randomised controlled trial for thrombolysis with no upper age limit.
Professor Hankey, who is participating in the IST-3 trial, said the registry results encouraged him to continue to randomise elderly patients for whom he was uncertain of the potential benefits and risks of thrombolysis.
He said the Australian clinical guidelines from the National Stroke Foundation for 2010 were that more than 80 years of age was a relative contraindication against use of thrombolysis and that it be used with caution.
Dr Stephen Read, visiting neurologist at Royal Brisbane Hospital and St Andrew’s War Memorial Hospital in Brisbane, said the National Stroke Audit of 2009 showed only about 3% of all patients with stroke in Australia received thrombolysis.(3)
As in most developed countries, about 30% of patients with ischaemic stroke in Australia were aged over 80 years.
“We have a fair bit of work to do there,” Dr Read said. “If this data helps increase the number of people who receive the treatment, it can only be a good thing.”
The BMJ study compared data on patients who received thrombolysis from the Safe Implementation of Treatments in Stroke-International Stroke Thrombolysis Register (SITS-ISTR) with a control group of patients who received placebo or a neuroprotective agent in the Virtual International Stroke Trials Archive (VISTA) trials.
Of 29 228 patients studied, 3439 were over 80 years old with an average age of 84.6 years in this group.
Functional outcomes after 3 months were significantly better in patients who received thrombolysis than in those who did not (odds ratio, 1.6).
This occurred independently in patients aged up to 80 years (OR, 1.6) and in those over 80 years (OR, 1.4), with significant benefit from age 41 to 90.
Dr Read said that although the results were derived from registry data and potentially subject to biases, they were helpful in reassuring clinicians that their use of thrombolysis in patients over the age of 80 was probably the right thing to do.
“Although I think we will all be more certain once there is some solid randomised controlled trial data, which will probably follow from studies including IST-3,” he said.
The main concern with thrombolysis in older people was that they might have a greater tendency to bleed catastrophically.
A BMJ editorial said quality improvement strategies were needed to ensure that elderly people, who had the highest risk of stroke, had equal access to effective treatment.(4)
1. BMJ 2010;341:c6046.
2. The Third International Stroke Trial.
3. National Stroke Foundation.
4. BMJ 2010;341:c5891.
Posted 29 November 2010