Effect of thrombolysis with alteplase within 6 h of acute ischaemic stroke on long-term outcomes (the third International Stroke Trial [IST-3]): 18-month follow-up of a randomised controlled trial

Abstract

Background: Few data are available from randomised trials about the effect of thrombolysis with alteplase on long-term functional outcome in patients who have had acute ischaemic stroke and no trial has reported effects on health-related quality of life. A secondary objective of the third International Stroke Trial (IST-3) was to assess the effect of thrombolysis on such outcomes at 18 months.

Methods: In this open-label, international, multicentre, randomised, controlled trial, 3035 patients with ischaemic stroke from 12 countries were randomly allocated within 6 h of onset via a secure central system to either intravenous alteplase (0·9 mg/kg; n=1515) plus standard care or standard care alone (control; n=1520). 2348 patients were scheduled for 18-month follow-up. For our main analysis, survivors were assessed at 18 months with the Oxford handicap scale (OHS; the primary outcome was the adjusted odds of OHS score 0-2). We also used the EuroQoL (EQ) instrument and asked questions about overall functioning and living circumstances. We analysed the OHS and the five EQ domains by ordinal logistic regression and calculated the mean difference between treatment groups in EQ utility index and visual analogue scale score. Analyses were adjusted for key baseline prognostic factors. This study is registered with controlled-trials.com, number ISRCTN25765518.

Findings: At 18 months, 408 (34·9%) of 1169 patients in the alteplase group versus 414 (35·1%) of 1179 in the control group had died (p=0·85). 391 (35·0%) of 1117 patients versus 352 (31·4%) of 1122 had an OHS score of 0-2 (adjusted odds ratio [OR] 1·28, 95% CI 1·03-1·57; p=0·024). Treatment was associated with a favourable shift in the distribution of OHS grades (adjusted common OR 1·30, 95% CI 1·10-1·55; p=0·002). Alteplase treatment was associated with significantly higher overall self-reported health (adjusted mean difference in EQ utility index 0·060; p=0·019). The differences between the groups in visual analogue scale score and the proportion living at home were not significant.

Interpretation: IST-3 provides evidence that thrombolysis with intravenous alteplase for acute ischaemic stroke does not affect survival, but does lead to statistically significant, clinically relevant improvements in functional outcome and health-related quality of life that are sustained for at least 18 months.

Funding: UK Medical Research Council, Health Foundation UK, Stroke Association UK, Research Council of Norway, AFA Insurances Sweden, Swedish Heart Lung Fund, The Foundation of Marianne and Marcus Wallenberg, Polish Ministry of Science and Education, the Australian Heart Foundation, Australian National Health and Medical Research Council, Swiss National Research Foundation, Swiss Heart Foundation, Assessorato alla Sanita (Regione dell'Umbria, Italy), and Danube University.

Figure 1

Trial profile EQ=EuroQoL. *Of the patients who were known to be alive at 18 months, 24 in the alteplase group versus 27 in the control group had a known date of death more than 18 months after enrolment, but their disability status at 18 months was unknown.

Figure 2

Kaplan-Meier survival curves