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26-07-2010 | Stroke | Article

SITS-ISTR supports thrombolysis window extension


Free abstract

MedWire News: Findings from the SITS-ISTR show that stroke thrombolysis in clinical practice can be extended to 4.5 hours after onset.

A recent pooled analysis of eight randomized thrombolysis trials concluded that the treatment had a favorable risk-benefit profile up to 4.5 hours after symptom onset.

In a commentary accompanying the current study, Scott Kasner (University of Pennsylvania Medical Center, Philadelphia, USA) and Steven Levine (State University of New York Health Science Center and School of Medicine, Brooklyn, USA) noted that "there has been some concern as to whether the results of trials could be replicated in broad-based clinical practice."

An added concern was that the positive results of the European Acute Stroke Study (ECASS) III, which showed benefits in patients treated up to 4.5 hours after stroke onset, would lead to a fall in admission-to-treatment times, due to a perceived reduction in urgency.

The current analysis of the SITS-ISTR (Safe Implementation of Treatment in Stroke- International Stroke Thrombolysis Registry), which appears in The Lancet Neurology, allays these fears. It shows that the median admission-to-treatment time remained at 65 minutes both before and after October 2008, when the ECASS III results were published.

In the first three quarters of 2008, 7% of 1023 patients were treated between 3 and 4.5 hours after symptom onset. From there to the end of 2009, this proportion increased three fold, to 22% of 1293 patients.

Intracerebral hemorrhage according to the SITS-Monitoring Study definition was slightly but significantly more common in patients treated in the later time period, a 44% increase relative to those treated within 3 hours, after accounting for confounders.

Hemorrhage rates were low overall, however, with less than 4.0-6.0% of patients suffering any hemorrhage and just 3.0-3.6% suffering parenchymal hemorrhage, report Nils Wahlgren (Karolinska University Hospital, Stockholm, Sweden) and team.

Patients treated 3.0-4.5 hours after stroke were 26% more likely to die within 3 months than were those treated within 3 hours, and they were 16% less likely to be functionally independent (modified Rankin Scale 0-2).

Kasner and Levine noted that this amounts to one extra symptomatic ICH for every 200 patients treated and one death for every 333.

"Not only do these results confirm that trials can be extended into practice, but they also show that alteplase treatment up to 4·5 h after stroke onset is increasingly accepted by clinicians worldwide," said the editorialists.

They concluded: "Many clinicians are already using alteplase; however, some will not use it without regulatory approval, and the time has come to overcome this hurdle."

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Eleanor McDermid