Abstracts

Rationale: Revascularization therapy of acute ischemic stroke (AIS) consists of endovascular treatment (EVT) with or without parallel intravenous thrombolysis (IVT) or IVT alone. The impact of treatment with EVT on poststroke epilepsy (PSE) risk is uncertain. The aim of this study was to assess the risk of PSE after EVT.

Methods: Data on patients treated with EVT with or without concomitant IVT between 2015 and 2019 were obtained from The Swedish National Quality register for patients that underwent EVT for stroke (EVAS register) (n=3,105). Two control groups with AIS treated with IVT alone (n=1,986), or with no acute treatment (n=2,286) were identified from The Swedish Stroke Register. The cohorts were matched by age, gender, acute NIHSS (The National Institutes of Health Stroke Scale) scores, and time period. Epilepsy-related diagnoses and prescriptions were collected from The National Patient Register (NPR) and The Swedish prescribed Drug Register. Data on death dates were collected from The Swedish Cause of Death Register. Patients were included in the study if 18-99 years and survival was >3 months after stroke. Patients with an epilepsy-related diagnosis prior to the acute stroke, brain tumor, unsuccessful recanalization due to futile vascular access or no occlusion on interoperative angiography were excluded. Poststroke epilepsy was defined as an epileptic seizure occurring at least 7 days after the index stroke. Cox Regression models were used to assess group differences and to identify risk factors associated with PSE after EVT.

Results: In total, 5,200 were included in the study (median age 73 years (interquartile range (IQR): 16, median follow-up time 18 months (IQR: 23.4)). The number of patients in different treatment groups were 2,120 EVT, 1,535 IVT and 1,545 with no acute stroke treatment. In the EVT group, 1,092 (51.5%) received parallel thrombolysis. The overall incidence of PSE was 410 (7.9%). The lowest survival-adjusted risk at 2 years was observed after EVT (6.5%) and the highest risk was seen in patients with no acute treatment (12.3%). The risk PSE was lower after EVT compared to no treatment, also with adjustment for age, gender, hemicraniectomy, and stroke severity by last known NIHSS after treatment.

Conclusions: In acute ischemic stroke, endovascular treatment (EVT) was associated with a lower risk of poststroke epilepsy compared to no treatment both in the univariate analysis and after adjustment for age and stroke severity. We plan further analyses to identify risk factors of PSE in the EVT group.

Funding: Please list any funding that was received in support of this abstract.: This study was supported by the Swedish Society for Medical Research (JZ), and the Swedish State under the ALF agreement (JZ).