Is thrombolysis beneficial when time of stroke onset is unknown?

Efficacy and safety of thrombolytic therapy for stroke with unknown time of onset: a meta-analysis of observational studies.

Zhu RL, Xu J, Xie CJ, Hu Y, Wang K.

J Stroke Cerebrovasc Dis 2020; 29:104742.



Recombinant tissue plasminogen activator (rt-PA) is one of the most effective therapies available for patients with known-onset stroke (KOS). Whether rt-PA treatment would improve functional outcomes in patients with stroke with unknown time of onset (UTOS) is undetermined, we aimed to systematically assess the efficacy and safety of thrombolysis for UTOS patients in this meta-analysis.


A systematic literature search of Medline, Embase, and Cochrane Library was conducted. We considered the relevant data comparing thrombolyzed UTOS patients versus nonthrombolyzed UTOS patients or thrombolyzed UTOS patients versus thrombolyzed KOS patients. Treatment efficacy and safety were measured according to modified Rankin Scale scores of 0-2 (mRS 0-2), and the presence of spontaneous intracerebral hemorrhage (SICH) or mortality at 90 days respectively.


A total of 11 studies with 2581 patients meeting the inclusion criteria were included in the meta-analysis. All the patients had an ischemic lesion that was assessed by imaging including computed tomography or magnetic resonance imaging. Among these studies, 6 compared the thrombolytic efficacy in thrombolyzed UTOS patients with that in nonthrombolyzed UTOS patients (mRS 0-2: odds ratio [OR] =1.76, 95% confidence interval [CI] 1.11-2.81, P = .02), and 8 studies compared thrombolyzed UTOS patients with thrombolyzed KOS patients (mRS 0-2: OR = 0.87, 95% CI 0.66-1.15, P = .33). The incidence of SICH and mortality at 90 days had no difference between thrombolyzed UTOS patients versus nonthrombolyzed UTOS patients and thrombolyzed UTOS patients versus thrombolyzed KOS patients (all P > .05).


Data from observational studies suggest that thrombolysis for unknown time of onset stroke UTOS had significantly favorable outcomes at 90 days compared with nonthrombolyzed patients.

This paper is cited in the Neurochecklist:

Thrombolysis: clinical use

Abstract link

By Marvin 101 – Own work, CC BY-SA 3.0, Link

By Ibrahim Imam

I am a UK Neurologist keen on general neurology, but with an interest in neuromuscular diseases. I maintain the neurology searchable database, I also blog at I share and discuss current issues around clinical neurology. I hope you find my blogs enlightening, practical, and even entertaining.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s