Intravenous thrombolysis for patients with reverse magnetic resonance angiography and diffusion-weighted imaging mismatch: SAMURAI and NCVC rt-PA Registries.

BACKGROUND AND PURPOSE: The characteristics of reverse magnetic resonance angiography and diffusion-weighted imaging (MRA-DWI) mismatch (RMM), defined as a large DWI lesion in the absence of major artery occlusion (MAO), remain unknown, especially in patients treated with intravenous recombinant tissue plasminogen activator (rt-PA).

METHODS: Patients with stroke in the middle cerebral artery territory were included. Early ischaemic changes (EIC) were assessed with the Alberta Stroke Program Early CT Score on DWI (DWI-ASPECTS). All patients were divided into four groups based on the presence of MAO and a DWI-ASPECTS cut-off value of <7. RMM was defined as DWI-ASPECTS <7 without MAO. Clinical characteristics, symptomatic intracerebral hemorrhage (sICH) and favorable functional outcome (modified Rankin Scale score 0-2) at 90 days were compared amongst the four groups.

RESULTS: Of the 486 patients enrolled (167 women, median age 74 years, median initial National Institutes of Health Stroke Scale score 13), reverse MRA-DWI mismatch was observed in 24 (5%). Of the clinical characteristics, cardioembolism was the only factor that was independently associated with RMM [odds ratio (OR) 5.49, 95% confidence interval (CI) 1.25-24.1]. Multivariable analyses revealed that patients with RMM more commonly had sICH than those with DWI-ASPECTS ≥ 7 irrespective of the presence (OR 5.44, 95% CI 1.13-26.1) or absence (13.1, 2.07-83.3) of MAO, and they had a more favorable functional outcome than those with DWI-ASPECTS < 7 plus MAO (7.45, 2.39-23.2).

CONCLUSION: RMM was observed in 5% of patients treated with rt-PA and associated with cardioembolism. Patients with RMM may benefit from thrombolysis compared with those with EIC with MAO, although increment in the rate of sICH is a concern.