Written by Clay Smith
For patients with unknown time of stroke onset, MRI characteristics may be able to discern the timing of the stroke and allow for thrombolytic therapy. Overall, outcomes were better with thrombolysis but at the possible cost of higher mortality and risk of intracranial bleed.
Why does this matter?
If a patient wakes up with stroke symptoms, there is no way to know an accurate time of onset, which precludes use of thrombolytic therapy. But if we estimate timing using MRI, lytics might still be helpful.
Better or bleed - tough choice
This was a RCT with 503 patients total that was stopped early because they ran out of money...seriously. They intended to enroll 800. For patients with unknown time of stroke onset (most occurred while asleep), MRI was performed and patients were randomized to receive alteplase or placebo if the MRI showed an, "ischemic lesion that was visible on MRI diffusion-weighted imaging but no parenchymal hyperintensity on fluid-attenuated inversion recovery (FLAIR), which indicated that the stroke had occurred approximately within the previous 4.5 hours." For the primary outcome of favorable neurological outcome at 90 days (modified Rankin scale 0-1), the alteplase group was better: 131/246 (53.3%) for alteplase; 102/244 patients (41.8%) for placebo (adjusted OR, 1.61; 95% CI 1.09 to 2.36). A familiar refrain with lytics in stroke; there was slightly higher mortality in the alteplase group and more intracranial bleeding, both of which were not statistically significant but may have been had they recruited enough patients. It appears MRI features may be able to guide lytic therapy for stroke patients with unknown time of onset and lead to a better outcome in more patients, assuming they are lucky enough not to have a head bleed and die.
MRI-Guided Thrombolysis for Stroke with Unknown Time of Onset. N Engl J Med. 2018 May 16. doi: 10.1056/NEJMoa1804355. [Epub ahead of print]
Reviewed by Thomas Davis
emDocs took an in-depth look at the new 2018 stroke guidelines.