A study published early online and in an upcoming edition of The Lancet found that the stroke drug alteplase is safe and effective even if administered 1 to 1.5 hours after the conventional 3-hour treatment window. Prof Nils Wahlgren (Karolinska University Hospital, Stockholm, Sweden) and colleagues also remind that the drug can still be safely administered within three hours of stroke.
Acute ischemic stroke is a condition characterized by a serious lack of blood supply to the brain. It is commonly treated with a drug called alteplase, which dissolves the thrombi (blood clot) that caused the stroke. Usually alteplase is administered within three hours after stroke, but Prof Wahlgren and colleagues, in the Safe Implementation of Treatments in Stroke – International Stroke Thrombolysis Registry (SITS-ISTR) study, tested the outcomes of patients who received intravenous alteplase 3 to 4.5 hours after stroke. Of the total sample, 664 patients received the drug 3 to 4.5 hours post-stroke and 11,865 received it within three hours.
The group that received later treatment received alteplase about 55 minutes, on average, later than the group that received earlier treatment – at 195 vs 140 min. In addition, the later group was about three years younger and had slightly lower stroke severity than the within 3 hour group. The results of the study revealed that outcome measures were similar between the two groups. For example, the mortality rate for the 3 to 4.5 hour group was 12.7% compared to 12.2% for the within 3 hours group. The brain hemorrhage rates were 2.2% and 1.6% and the proportions of patients retaining independence were 58.0% and 56.3%, respectively.
“Our results show that the rates of symptomatic intracerebral haemorrhage, mortality, and independence at 3 months follow-up in routine clinical practice are similar between patients for whom treatment was started between 3 and 4.5 h and for those treated within 3 h after ischaemic stroke onset,” write the authors. “Our findings lend support to those of the meta-analysis suggesting a potentially longer timeframe for intravenous [use of alteplase] of 4.5 h.”
Dr Georgios Tsivgoulis and Dr Andrei Alexandrov (Comprehensive Stroke Center, University of Alabama at Birmingham Hospital, Birmingham, Alabama USA) write in an accompanying editorial that: “Extension of the timeframe of systemic thrombolysis seems to be a safe option for patients with acute stroke…We are looking forward to moving away from rigid timeframes to treatment based on imaging that can assess brain pathophysiology and tissue viability.”
Thrombolysis with alteplase 3-4.5 h after acute ischaemic stroke (SITS-ISTR): an observational study
Nils Wahlgren, Niaz Ahmed, Antoni Dávalos, Werner Hacke, Mónica Millán, Keith Muir, Risto O Roine, Danilo Toni, Kennedy R Lees, for the SITS investigators
The Lancet (2008).
DOI:10.1016/S0140-6736(08)61339-2
Written by: Peter M Crosta