Outcomes and safety of intravenous thrombolysis in minor ischaemic stroke: a real-world retrospective cohort study

Abstract Background The benefit-risk profile of intravenous thrombolysis (IVT) in minor ischaemic stroke remains controversial. We evaluated real-world outcomes and safety of IVT in a centre with a liberal thrombolysis policy. Methods We performed a retrospective cohort study of consecutive adult patients treated with IVT for suspected acute ischaemic stroke with admission NIHSS 0–5 at Stavanger University Hospital between 2008 and 2023. A liberal thrombolysis policy was defined as a treatment threshold that does not exclude patients on the basis of a low NIHSS score or apparently non-disabling symptoms alone. Patients were stratified into NIHSS 0–2 and NIHSS 3–5 subgroups. Outcomes included favourable early neurological status, defined as NIHSS 0–1 within 24 h, functional independence at 90 days (mRS 0–2), poor outcome (mRS 3–6), stroke mimic diagnosis, and symptomatic intracranial haemorrhage (sICH). Multivariable logistic regression analyses were performed in confirmed stroke cases, excluding stroke mimics. Results Among 2,008 IVT-treated patients, 1270 (63%) had admission NIHSS 0–5: 744 (59%) had NIHSS 0–2 and 526 (41%) had NIHSS 3–5. Stroke mimics accounted for 335 cases (26%) and were more frequent in the NIHSS 0–2 group than in the NIHSS 3–5 group (29% versus 23%; p = 0.041). Among patients with available 90-day mRS, 602/697 (86%) achieved functional independence, with higher rates in the NIHSS 0–2 group than in the NIHSS 3–5 group (93% vs. 76%; p < 0.001). sICH occurred in four patients (< 1%), with no events among stroke mimics. In adjusted analyses restricted to confirmed stroke cases, NIHSS 0–2 was associated with higher odds of favourable early neurological status and functional independence compared with NIHSS 3–5. Conclusions In this real-world cohort from a centre with a liberal thrombolysis policy, IVT-treated patients with minor stroke symptoms had favourable functional outcomes and very low complication rates of sICH. The contribution of this cohort lies in describing what a liberal thrombolysis policy produces in unselected routine practice, as opposed to the narrowly defined populations enrolled in randomised trials. These findings provide clinically relevant safety data, but they cannot demonstrate efficacy and should be interpreted descriptively in the absence of an untreated comparator group.