Safe Implementation of Treatments in Stroke: a study on intravenous thrombolysis in patients over 80 years of age with acute ischaemic stroke.

Objectives: To investigate the safety and efficacy outcomes of intravenous thrombolysis (IVT) in patients aged >80 years with acute ischaemic stroke (AIS) after IVT was approved in this patient population in several European and non-European countries during 2018-2019.

Design: This is an observational registry study using prospectively collected data from the Safe Implementation of Treatment in Stroke (SITS) registry. Comparisons will be performed between patients treated post-approval (July 2018 to December 2021) period with those treated pre-approval (June 2015 to June 2018) period using propensity score matching (PSM).

Setting: This is a multicentre international study in hospitals treating AIS with IVT.

Participants: Patients aged >80 years who otherwise followed the IVT Summary of Product Characteristics of European countries as part of the mutual recognition procedure.

Primary And Secondary Outcomes: The main outcomes were symptomatic intracerebral haemorrhage per SITS monitoring study definition, death and functional independency as defined by a modified Rankin Scale score of 0-2 at 90 days.

Results: After PSM, 614 patients remained in each group (mean age 87 years, 39% males). All baseline data were well balanced after PSM. There were no statistically significant differences in outcomes between pre- and post-approval patients for SICH (2.5% vs 2.3%, risk ratio (RR) 1.064, 95% CI 0.345-1.784), death (25.3% vs 28.4%, RR 0.889, 0.699-1.08) and functional independency at 90 days (40.3% vs 37%, RR 1.089, 0.942-1.237).

Conclusions: In this observational study of IVT treatment in patients >80 years of age with AIS before and after formal approval for this treatment, we did not find any difference in outcomes between the pre- and post-approval periods.