Updating estimates of the number of UK stroke patients eligible for endovascular thrombectomy: incorporating recent evidence to facilitate service planning.

Introduction: Endovascular thrombectomy (EVT) is a highly effective treatment for acute ischaemic stroke due to large arterial occlusion (LAO). To support decisions about service provision, we previously estimated the annual UK population eligible for EVT as ∼10% of stroke admissions. Since then, several trials have produced evidence that could alter these figures. We update our estimates considering information from studies and trials reporting 2018-2021 on incidence, presentation time and stroke severity and consider the possible impact of predicted demographic changes in the next 10-20 years. Patients and Methods: We produce an updated decision tree describing the EVT eligible population for UK stroke admissions. One-way sensitivity analyses (using upper and lower confidence intervals for estimates at each branch of our decision tree) were used to identify where further research evidence is necessary to increase certainty around estimates for numbers of EVT eligible patients. Results: The updated estimate for the number of UK stroke patients eligible for EVT annually was between 10,020 (no advanced imaging in early presenting patients) and 9,580 (advanced imaging in all early presenting patients), which compared with our estimates in 2017 is a minimal reduction. One-way sensitivity analyses established that enhanced evidence about eligibility for milder strokes, ASPECTS scores and pre-stroke disability are offset by evidence regarding a lower incidence of LAO. Importantly, predicted increases in life expectancy by 2040 may increase thrombectomy need by 40%. Discussion: Information from additional randomised trials published during 2018-2020 with updated estimates of LAO prevalence had a minimal impact on overall estimates of stroke patients eligible for EVT in the UK. Ongoing research into the benefits of EVT for patients with mild stroke or European Stroke Journal For Peer Review lower ASPECTS scores has the potential to increase the estimates of the eligible population; future need for EVT will increase with the ageing population. Conclusion: Our updated analyses show overall numbers eligible little changed, but evidence from ongoing trials and demographic changes have the potential to increase the need for EVT significantly.