Well, PRISMS demonstrated unfavorable results.
MARISS tried to ascertain predictors of poor outcome in mild stroke, and intravenous thrombolysis was not associated with an effect on the primary outcome.
Now, again, we examine thrombolysis in “mild” stroke, in this case, NIHSS ≤3 – and fail.
Like MARISS, this is a retrospective dredge of patients selected by the treating clinicians to receive either intravenous thrombolysis or, in this case, dual-antiplatelet therapy with clopidogrel and aspirin. The population included for analysis is the Austrian Stroke Unit Registry from 2018 until 2019, an original cohort of 53,899 patients. Of these, 29,252 were NIHSS ≤3, but exclusions meant nearly 25,000 were left out – primarily those whose strokes were the result of atrial fibrillation, or whose treating clinicians chose platelet monotherapy instead of dual antiplatelet therapy.
The remaining ~4,000 were analyzed both in their unadjusted cohorts, as well as propensity scored cohorts comprised of roughly 20% of the original. In the unadjusted cohorts, efficacy and safety outcomes were universally worse in those selected for thrombolysis – but, of course, were generally more severe stroke syndromes. After propensity score matching, these differences generally disappeared – except a preponderance of sICH in the thrombolysis cohort.
The authors here conclude there’s no evidence of superiority for thrombolysis in mild stroke, and their results fit broadly with those from other cohorts. It’s observational and unreliable, but it ought to be a very reasonable stance to withhold thrombolysis for mild strokes pending trials conclusively demonstrating which, if any, mild strokes do improve with thrombolysis.