Hierarchical composite outcomes in acute ischaemic stroke with large infarct: a win ratio analysis of the TENSION trial

Introduction Traditional endpoints in acute ischaemic stroke trials, most commonly the mRS, incompletely capture the full spectrum of patient outcomes. The win ratio (WR) is a hierarchically structured composite outcome measure that prioritises endpoints according to clinical importance. In this study, we applied win statistics to investigate which components drive the overall treatment effect. Patients and methods Of 253 patients in the TENSION (Efficacy and safety of ThrombEctomy iN Stroke with extended leSION and extended time window) trial, 125 were randomised to EVT + BMT and 128 to BMT alone. Endpoints were ranked hierarchically: (1) time to death, (2) mRS at 12 months, (3) occurrence of any serious adverse event and (4) EuroQOL 5-dimension scores at 12 months. Outcomes were analysed using win statistics. Results The overall WR was 1.61 (95% CI, 1.19–2.18; P = .002), indicating a relative frequency of wins for EVT + BMT of approximately 60% among untied pairwise comparisons. The win difference was 22.8% (95% CI, 8.3%–36.3%; P = .002), of which 15.7% were attributable to survival. Win ratios were consistent across prespecified subgroups, including both sexes, age ≤ 80 years, baseline mRS 0–1, conscious patients, ASPECTS 5 and M1 occlusions. Discussion The WR provides an informative complement to conventional mRS-based analyses in acute ischaemic stroke trials. Our hierarchical composite outcome analysis demonstrated how ordering of hierarchical components affects the resulting estimates, with the predominant treatment effect in TENSION being driven by improved survival. Conclusion These findings support the complementary use of hierarchical composite outcomes in future neurointerventional trials.