TOPLINE

In patients with ischaemic stroke and mild neurologic deficits, intravenous thrombolysis (IVT) administered within 90 minutes of symptom onset was associated with improvement in functional outcomes, but this beneficial effect progressively diminished when the treatment was delayed beyond 90 minutes.

METHODOLOGY

• Researchers performed an observational study using data from the Norwegian Stroke Registry from 2014 to 2022 to assess the effect of time to IVT treatment in patients with ischaemic stroke presenting with mild neurologic deficits at admission.
• The primary analysis included a mean of 7722 patients with ischaemic stroke and a National Institutes of Health Stroke Scale score of 0-2 (mean age, 69 years; 39.5% women) using an impute-then-exclude approach.
• Secondary analyses included 5601 patients (mean age, 68 years; 39.1% women) using an exclude-then-impute approach and 4061 patients (mean age, 68 years; 37.7% women) using a complete-case approach.
• Patients were categorised into four groups on the basis of the time to IVT: those who did not receive IVT, those who received IVT within 90 minutes of symptom onset, those who received IVT between 91 and 180 minutes, and those who received IVT after 180 minutes.
• Functional outcomes at 3 months post-stroke were assessed using the modified Rankin scale (mRS), ranging from 0 (no symptoms) to 6 (dead), and were compared across groups.

TAKEAWAY

• In the primary analysis, patients who received IVT within 90 minutes of symptom onset had 19% lower odds of a worse mRS score at 3 months post-stroke than those who did not receive IVT (odds ratio [OR], 0.81; 95% CI, 0.71-0.92).
• IVT administered between 91 and 180 minutes (OR, 0.90) or after 180 minutes (OR, 0.98) did not show any significant effect on functional outcomes.
• Secondary analyses showed similar results; a positive effect on functional outcomes was observed when IVT was administered within 90 minutes of symptom onset, whereas no significant effects were observed when IVT was administered beyond 90 minutes.
• Among patients treated with IVT in the complete-case dataset, 3.2% experienced symptomatic intracranial haemorrhage.

IN PRACTICE

"Our findings are largely consistent with those of recent studies, suggesting that IVT does not confer a significant benefit in patients with minor stroke; however, our data suggest that IVT may improve functional outcome when administered within 90 min of stroke onset. The beneficial effect appears to diminish as time from ictus increases," the authors wrote.

"Due to the risk of sICH [symptomatic intracranial haemorrhage], careful consideration of the risk-benefit ratio is recommended, particularly for patients presenting later than 90 min after stroke onset," they added.

SOURCE

This study was led by Torunn Varmdal, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway. It was published online on July 29, 2026, in Acta Neurologica Scandinavica.

LIMITATIONS

Patients who did not receive IVT differed from those who received IVT at baseline. The possibility of unmeasured confounding cannot be excluded, which may have affected the results and introduced bias. Functional outcome scores at 3 months among survivors were collected partly by health personnel and partly by the patients themselves or their next of kin, which may have introduced variability in outcome scoring.

DISCLOSURES

This study did not receive any funding. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.