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Thrombolysis for acute ischaemic stroke
Karolinska Stroke Update Consensus Statement 2002
| The following Consensus Statement was adopted by the 4th Karolinska Stroke Update meeting on
November 12, 2002. The consensus statement was proposed by the chairpersons in the session, Professor Markku Kaste, Helsinki, and Professor Rüdiger von Kummer, Dresden, together with the speakers in the session. The statement was then finally approved by the participants of the meeting, after listening to the different presentations. The speakers in this session were Professor Joanna Wardlaw, Edinburgh, Associate Professor Nils Gunnar Wahlgren, Stockholm, Dr Lars Thomassen, Bergen, Dr Jan Sobesky, Cologne and Professor Rüdiger von Kummer, Dresden. |
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Thrombolysis for acute ischemic stroke 1.
Intravenous rt-PA within 3 hours after the onset of symptoms in patients
with acute ischaemic stroke is a highly effective treatment in selected
patients (grade A evidence). The use of rt-PA is supported by results
from randomised controlled trials, pooled
analysis of six randomised rt-PA trials, meta-analyses and post-approval
data.
According to meta-analyses, for patients given rt-PA within 3
hours of ischaemic stroke approximately 1 out of 10 more will be
independent, 1 of 22 will suffer symptomatic haemorrhage and 1 in 100
fewer may die as a result of the treatment (grade A evidence). 2.
The
pooled analysis of the 2776 patients of the ATLANTIS, ECASS and NINDS
rt-PA trials suggest benefit up to 4 ½ hours after the onset of an
ischaemic stroke but the treatment benefit decreases with the time. Odds
ratios for favourable
outcomes with rt-PA in the pooled analyses were 2.8 (95%CI 1.8-4.5) in
the 0-90, 1.5 (95%CI 1.1-2.1) in the 91-180, 1.4 (95%CI 1.1-1.9) in the
181-270 and 1.2 (95%CI 0.9-1.5) in the 271-360 minute time windows. The
use of rt-PA up to 6 hours is supported by the results of a
meta-analysis of tabular data (grade A evidence) but
further randomised trials will be required to determine the latest time
window (grade A evidence). 3.
Outside randomised controlled trials, it is recommended that the therapeutic use of intravenous rt-PA should
follow published guidelines (with local modifications as appropriate),
and the labelling approved by Health Authorities and should be
subject to continuous quality control. 4.
In most open studies the safety and efficacy of intravenous rt-PA in
routine clinical practice is comparable to randomised studies. A
meta-analysis of 12 post-approval open series with 2529 patients treated
within 3 hours revealed comparable rates of symptomatic haemorrhages
(5.1 vs 6.4 % in the NINDS trial), of favourable outcome as defined by
mRS 0-1 pts (37,1 vs 39% in the NINDS trial) and of initial stroke
severity as defined by the baseline NIHSS (14 vs 14 in the NINDS trial). 5.
Thrombolysis within 3 hours has been approved in the United States,
Canada, Brazil, Germany and recently also in the European Union. The
evidence strongly supports that rt-PA is made available for routine
clinical use to treat stroke patients in adequately resourced
and experienced centres. However, there is an obvious need for
continuous education and for trained stroke specialists to guarantee
safe and efficient use of thrombolysis. The development of hospital
services designed to deliver early thrombolysis 24 hours a day for acute
ischaemic stroke is encouraged. 6.
The approval of rt-PA in ischaemic stroke by the European Union Health
Authorities was conditional. The first condition was that all treated
patients should be included in the Safety Implementation of Thrombolysis
in Stroke - The Monitoring Study register (SITS-MOST). The second
condition was a double-blind, randomised, placebo-controlled trial of IV
rt-PA in ischaemic stroke where thrombolysis is initiated between 3 and
4 hours after stroke onset (ECASS III). 7.
The heterogeneity for good outcome in meta-analyses implies that more
data are needed on how to identify the patients most likely to benefit
and least likely to be harmed by thrombolysis. The role of patient
characteristics, stroke severity, stroke subtype, vascular
lesions, stroke
pathophysiology, concomitant
disease, and drug treatments should be further evaluated in future
trials, meta-analyses, phase IV studies and the SITS-MOST
register. 8.
It
is recommended that some future trials of safety and efficacy of
thrombolysis should assess modern imaging techniques as a part of the
protocol to help in patient selection and in monitoring of the effects
of therapy. Extended ischaemic oedema as detected by CT should weigh against the use
of thrombolysis (grade B evidence). MR diffusion and perfusion
weighted imaging may reveal brain tissue at risk that can be salvaged with thrombolysis in individual patients within a
3-hour time window and possibly even longer (grade C evidence). Other
imaging modalities including perfusion CT, MR angiography, SPECT and TCD
may be useful in selecting patients, in
assessing arterial pathology and in monitoring the effects of therapy (grade
C evidence). However, further
data from randomised trials incorporating these new imaging modalities
are required, as - although each may provide extra prognostic
information - they may also increase time to treatment and hence reduce
the benefit of rt-PA. 9.
The limitation of the 3-hour time window is the major factor, which
prevents wider application of thrombolysis in ischaemic stroke. ECASS
III, IST-3 and EPITHET aim at extending the time window. This may have
an important public health impact in Europe. It is recommended that new
thrombolytic agents, wider time windows and thrombolysis
together with neuroprotective agents, should be evaluated in future
randomised trials to try to increase the effectiveness and to decrease the
risks of thrombolysis. 10.
Another factor that prevents the wider application of
thrombolysis in ischaemic stroke is the concern that brain haemorrhage
may harm the patient. In the pooled analysis (ATLANTIS, ECASS and NINDS), the
rate of large space occupying haematoma (PH) was 1.1% in the placebo
group and 5.9% in the rt-PA group. Despite this 5.4-fold
risk, rt-PA significantly increased the overall chance of not being
disabled or dead after stroke. This observation suggests, that not all
of these haemorrhages were symptomatic. Accordingly, the
definition of symptomatic brain haemorrhage should fulfil the following
criteria: “Clinical deterioration by > 4 p NIHSS (or equivalent)
combined with brain haemorrhage without other pathology, or clinical
deterioration by > 4 p NIHSS (or equivalent) combined with cerebral
haemorrhage within an ischaemic lesion
where any mass effect is largely attributed the haemorrhage. Any
haemorrhage in large space-occupying infarction should not be considered
as “symptomatic haemorrhage” but rather “ischaemic oedema”, and
data should be collected on ischaemic oedema in future trials. 11.
The impact of antiplatelet treatment prior to the stroke on the
risk of symptomatic haemorrhage following stroke needs to be studied
further although existing data do not indicate an increased risk of
symptomatic haemorrhage (grade B evidence). Furthermore, the safety and
efficacy of postthrombolytic antithrombotic treatment and
anticoagulation to prevent re-occlusion needs to be analyzed in
randomised trials.
12.
Future studies should include collection of data to allow the assessment
of the impact on health economics and on quality of life of rt-PA in
acute ischaemic stroke.
The public should be educated of the value of early expert assessment
and treatment.
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