Update on the third international stroke trial (IST-3) of thrombolysis for acute ischaemic stroke and baseline features of the 3035 patients recruited

Background Intravenous recombinant tissue plasminogen activator (rtPA) is approved in Europe for use in patients with acute ischaemic stroke who meet strictly defined criteria. IST-3 sought to improve the external validity and precision of the estimates of the overall treatment effects (efficacy and safety) of rtPA in acute ischaemic stroke, and to determine whether a wider range of patients might benefit. Design International, multi-centre, prospective, randomized, open, blinded endpoint (PROBE) trial of intravenous rtPA in acute ischaemic stroke. Suitable patients had to be assessed and able to start treatment within 6 hours of developing symptoms, and brain imaging must have excluded intracranial haemorrhage and stroke mimics. Results The initial pilot phase was double blind and then, on 01/08/2003, changed to an open design. Recruitment began on 05/05/2000 and closed on 31/07/2011, by which time 3035 patients had been included, only 61 (2%) of whom met the criteria for the 2003 European approval for thrombolysis. 1617 patients were aged over 80 years at trial entry. The analysis plan will be finalised, without reference to the unblinded data, and published before the trial data are unblinded in early 2012. The main trial results will be presented at the European Stroke Conference in Lisbon in May 2012 with the aim to publish simultaneously in a peer-reviewed journal. The trial result will be presented in the context of an updated Cochrane systematic review. We also intend to include the trial data in an individual patient data meta-analysis of all the relevant randomised trials. Conclusion The data from the trial will: improve the external validity and precision of the estimates of the overall treatment effects (efficacy and safety) of iv rtPA in acute ischaemic stroke; provide: new evidence on the balance of risk and benefit of intravenous rtPA among types of patients who do not clearly meet the terms of the current EU approval; and, provide the first large-scale randomised evidence on effects in patients over 80, an age group which had largely been excluded from previous acute stroke trials

The benefits and harms of intravenous thrombolysis with recombinant tissue plasminogen activator within 6 h of acute ischaemic stroke (the third international stroke trial [IST-3]): a randomised controlled trial

Background Thrombolysis is of net benefi t in patients with acute ischaemic stroke, who are younger than 80 years of age and are treated within 4·5 h of onset. The third International Stroke Trial (IST-3) sought to determine whether a wider range of patients might benefi t up to 6 h from stroke onset. Methods In this international, multicentre, randomised, open-treatment trial, patients were allocated to 0·9 mg/kg intravenous recombinant tissue plasminogen activator (rt-PA) or to control. The primary analysis was of the proportion of patients alive and independent, as defi ned by an Oxford Handicap Score (OHS) of 0–2 at 6 months. The study is registered, ISRCTN25765518. Findings 3035 patients were enrolled by 156 hospitals in 12 countries. All of these patients were included in the analyses (1515 in the rt-PA group vs 1520 in the control group), of whom 1617 (53%) were older than 80 years of age. At 6 months, 554 (37%) patients in the rt-PA group versus 534 (35%) in the control group were alive and independent (OHS 0–2; adjusted odds ratio [OR] 1·13, 95% CI 0·95–1·35, p=0·181; a non-signifi cant absolute increase of 14/1000, 95% CI –20 to 48). An ordinal analysis showed a signifi cant shift in OHS scores; common OR 1·27 (95% CI 1·10–1·47, p=0·001). Fatal or non-fatal symptomatic intracranial haemorrhage within 7 days occurred in 104 (7%) patients in the rt-PA group versus 16 (1%) in the control group (adjusted OR 6·94, 95% CI 4·07–11·8; absolute excess 58/1000, 95% CI 44–72). More deaths occurred within 7 days in the rt-PA group (163 [11%]) than in the control group (107 [7%], adjusted OR 1·60, 95% CI 1·22–2·08, p=0·001; absolute increase 37/1000, 95% CI 17–57), but between 7 days and 6 months there were fewer deaths in the rt-PA group than in the control group, so that by 6 months, similar numbers, in total, had died (408 [27%] in the rt-PA group vs 407 [27%] in the control group)

Effect of alteplase on the CT hyperdense artery sign and outcome after ischemic stroke

Objective: To investigate whether the location and extent of the CT hyperdense artery sign (HAS) at presentation affects response to IV alteplase in the randomized controlled Third International Stroke Trial (IST-3). Methods: All prerandomization and follow-up (24–48 hours) CT brain scans in IST-3 were assessed for HAS presence, location, and extent by masked raters. We assessed whether HAS grew, persisted, shrank, or disappeared at follow-up, the association with 6-month functional outcome, and effect of alteplase. IST-3 is registered (ISRCTN25765518). Results: HAS presence (vs absence) independently predicted poor 6-month outcome (increased Oxford Handicap Scale [OHS]) on adjusted ordinal regression analysis (odds ratio [OR] 0.66, p , 0.001). Outcome was worse in patients with more (vs less) extensive HAS (OR 0.61, p 5 0.027) but not in proximal (vs distal) HAS (p 5 0.420). Increasing age was associated with more HAS growth at follow-up (OR 1.01, p 5 0.013). Treatment with alteplase increased HAS shrink- age/disappearance at follow-up (OR 0.77, p 5 0.006). There was no significant difference in HAS shrinkage with alteplase in proximal (vs distal) or more (vs less) extensive HAS (p 5 0.516 and p 5 0.580, respectively). There was no interaction between presence vs absence of HAS and benefit of alteplase on 6-month OHS (p 5 0.167). Conclusions: IV alteplase promotes measurable reduction in HAS regardless of HAS location or extent. Alteplase increased independence at 6 months in patients with and without HAS. Classification of evidence: This study provides Class I evidence that for patients within 6 hours of ischemic stroke with a CT hyperdense artery sign, IV alteplase reduced intra-arterial hyperdense thrombus