Impact of intravenous thrombolysis on functional outcome in patients with mild ischemic stroke without large vessel occlusion or rapidly improving symptoms

Background Optimal treatment strategy in patients with mild ischemic stroke remains uncertain. While functional dependency or death has been reported in up to one-third of non-thrombolyzed mild ischemic stroke patients, intravenous thrombolysis is currently not recommended in this patient group. Emerging evidence suggests two risk factors—rapid early improvement and large vessel occlusion—as main associates of unfavorable outcome in mild ischemic stroke patients not undergoing intravenous thrombolysis. Aims To analyze natural course as well as safety and three-month outcome of intravenous thrombolysis in mild ischemic stroke without rapid early improvement or large vessel occlusion. Methods Mild ischemic stroke was defined by a National Institute of Health Stroke Scale score ≤6. We used the modified Rankin Scale (mRS) to compare three-month functional outcome in 370 consecutive mild ischemic stroke patients without early rapid improvement and without large vessel occlusion, who either underwent intravenous thrombolysis (n = 108) or received best medical treatment (n = 262). Results Favorable outcome (mRS ≤ 1) was common in both groups (intravenous thrombolysis: 91%; no intravenous thrombolysis: 90%). Although intravenous thrombolysis use was independently associated with a higher risk of asymptomatic hemorrhagic transformation (OR = 4.62, p = 0.002), intravenous thrombolysis appeared as an independent predictor of mRS = 0 at three months (OR = 3.33, p < 0.0001). Conclusions Mild ischemic stroke patients without rapidly improving symptoms and without large vessel occlusion have a high chance of favorable three-month outcome, irrespective of treatment type. Patients receiving intravenous thrombolysis, however, more often achieved complete remission of symptoms, which particularly in mild ischemic stroke may constitute a meaningful endpoint.