MRI‐based intravenous thrombolysis in stroke patients with unknown time of symptom onset

Abstract

Currently, stroke patients with unknown time of symptom onset (UTOS) are excluded from therapy with intravenous tissue Plasminogen Activator. We hypothesized that MRI-based intravenous thrombolysis is safe in UTOS. We analyzed radiological and clinical data as well as outcomes of stroke patients (including UTOS) who received intravenous thrombolytic therapy after MRI. Compared to patients with known time of symptom onset (n=131), UTOS (n=17) were older (81, 71-88 vs. 75 years, 66-82, P=0.03), had a longer median time between last-seen-well and thrombolysis (12.3 h, IQR 11.5-15.2 h vs. 2.1 h, 1.8-2.8 h, P<0.01), had a longer median door-to-needle time (86 min, 49-112 vs. 60 min, 49-76, P=0.02), and a higher rate of arterial obstruction on MR-angiography (82.4% vs. 56.5%, P=0.04). No symptomatic intracerebral hemorrhage occurred in UTOS. After 3 months, there was no significant difference between groups concerning good functional outcome (modified Rankin Scale 0-2; 35.3% vs. 49.6%, P=0.26) or mortality (0% vs. 15.3%, P=0.08). In multivariate analyses including age, gender, baseline NIHSS, and atrial fibrillation UTOS did not have an independent effect on good functional outcome after 3 months (OR 1.16; 0.32-4.12, P=0.81). Thrombolysis after MRI seems safe and effective in UTOS. This observation may encourage those who plan prospective placebo-controlled trials of thrombolytics in this subgroup of stroke patients.