Incorporating evidence from recent trials in to estimates of stroke patients eligible for thrombectomy

Introduction: We previously estimated the number of stroke patients in the UK who would be eligible for mechanical thrombectomy (MT) as between 9,620 and 10,920 using published evidence from randomised control trials and registries. We have updated our estimates in light of new evidence available since 2016.

Methods: A decision tree with 12 steps depicting eligibility according to key clinical and radiological characteristics was used to estimate the eligible population. It includes pathways using advanced imaging within and beyond 6 hours after stroke onset. The impact of new evidence was reviewed at each step to recalculate the eligible population.

Results: 2 trials; DAWN (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention with Trevo) and DEFUSE 3 (Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution) reported new evidence about MT eligibility amongst late presenters. Spontaneous recanalisation rates and MT outcomes amongst early presenting patients were reassessed using data from the Endovascular Stroke Trials' (HERMES) Collaboration. We estimate that an additional 490 early presenting and 205 late presenting patients are eligible for thrombectomy. This equates to up to 14% (11,615/83,000) of UK emergency stroke admissions.

Conclusion: Evidence from HERMES of benefits for patients with ASPECTS ≥ 5 is responsible for the largest increase in our estimate, although partly moderated by spontaneous recanalisation. New evidence of benefit in patients presenting between 12 and 24 hours increased eligibility in this group indicating the important role of advanced imaging in identifying late presenting patients who could benefit from MT.