Intravenous thrombolysis for acute ischemic stroke patients presenting with mild symptoms

Background: Thrombolysis of ischemic stroke patients presenting with mild symptoms is controversial.

Aim: We aimed to describe the clinical outcome and frequency of infarcts and symptomatic intracerebral hemorrhages on follow-up imaging of such thrombolysis-treated patients.

Methods: Our cohort included 1398 consecutive ischemic stroke patients treated with intravenous thrombolysis at the Helsinki University Central Hospital, years 1995-2010. We analyzed the patients according to baseline National Institutes of Health Stroke Scale: ≤2, 3-4, 5-6, and >6. In our institution, visualization of an artery occlusion or perfusion deficit is required for thrombolysis with National Institutes of Health Stroke Scale ≤ 2. We used univariate and multivariable methods to describe the cohort and study associations between the variables. Excellent three-month outcome was defined as modified Rankin Scale 0-1.

Results: Fifty-eight (4·1%) patients were treated with National Institutes of Health Stroke Scale ≤ 2, another 194 (13·6%) with 3-4 points, and 236 (16·5%) with 5-6 points. With National Institutes of Health Stroke Scale ≤ 2, 45 (78%) of the patients had excellent three-month outcome, achieved in 116 (59%) patients with National Institutes of Health Stroke Scale 3-4, in 130 (55%) with National Institutes of Health Stroke Scale 5-6, and in 241 (26%) with National Institutes of Health Stroke Scale > 6. Frequencies of symptomatic intracerebral hemorrhage (European Cooperative Acute Stroke Study-2) were 0%, 2·6%, 2·1%, and 8·1%, and visible infarcts on follow-up imaging 48%, 43%, 48%, and 74%, respectively. In patients with baseline National Institutes of Health Stroke Scale ≤ 6, poor outcome was associated with previous stroke, diabetes, elevated admission blood glucose, and development of intracerebral hemorrhage.

Conclusions: Half of patients presenting with National Institutes of Health Stroke Scale 0-6 developed an infarction despite thrombolysis, and 40% had poor outcome, which was associated with glucose metabolism and hemorrhagic complications. Managing thrombolysis candidates with mild symptoms warrants individual consideration often supported by multimodal imaging.