Title : Modeling early neurologic trajectories after elevated leg positioning (ELP): A secondary analysis of the LEG-UP randomized feasibility study
Abstract:
Objective: To evaluate the association between randomized assignment to ELP and early neurologic trajectory, assessed using the day-7 National Institutes of Health Stroke Scale (NIHSS) after adjusting for baseline neurologic severity.
Background: Elevated leg positioning (ELP) is a noninvasive intervention that may augment venous return and cerebral perfusion during acute ischemic stroke. The association between ELP and early neurologic recovery has not been established, and prior positioning trials have not demonstrated plausible functional benefit.
Design/Methods: Secondary analysis of the LEG-UP randomized, open-label, blinded-endpoint feasibility study, which randomized 50 participants with acute moderate ischemic stroke 1:1 to ELP or control. The primary outcome was day-7 NIHSS score, analyzed by ANCOVA with randomized allocation and baseline NIHSS as predictors. A 2000-replicate nonparametric bootstrap was used to assess the stability of the estimate.
Results: Among 50 randomized participants, after adjusting for baseline NIHSS scores, ELP was associated with a 1.95-point lower day-7 NIHSS score compared with control (adjusted difference, −1.95; 95% CI, −3.04 to −0.85; p=.0008; ω²p=0.1903). The estimated marginal mean day-7 NIHSS was 7.45 (95% CI, 6.67–8.22) in the ELP group versus 9.39 (95% CI, 8.62–10.17) in the control group. Baseline NIHSS was strongly prognostic (coefficient, 1.35; 95% CI, 1.17–1.53; p<.001). No early neurologic deterioration occurred in either group. Among the 47 participants with 90-day follow-up, favorable functional outcome (mRS 0–2) was present in 11 of 23 control participants (47.8%) and 14 of 24 ELP participants (58.3%).
Conclusion: ELP was associated with a lower adjusted day-7 NIHSS score compared with control. Given the small sample size, the feasibility design, and the short-interval surrogate nature of the day-7 NIHSS endpoint, these results do not establish clinical efficacy. However, they do support the feasibility of the protocol and provide a preliminary effect-size estimate to inform the sample-size calculation and endpoint selection of an adequately powered, blinded, multicenter randomized trial designed to assess functional outcomes.
Keywords: acute ischemic stroke; elevated leg positioning; NIHSS; early neurologic trajectory; analysis of covariance; feasibility trial; LEG-UP
