Author Response: Endovascular vs Medical Management for Late Anterior Large Vessel Occlusion With Prestroke Disability: Analysis of CLEAR and RESCUE-Japan

We thank Dr. Bruno and Dr. Nichols for their thoughtful comment of our CLEAR and RESCUE-Japan analysis on endovascular therapy of late large vessel occlusion with prestroke disability.¹

We share their concerns regarding the limitations of the modified Rankin Scale (mRS). In a prior commentary regarding sensibility of a prestroke mRS,² the authors suggested a Barthel Index or another measure to be better in capturing functional abilities prior to or following stroke. A prestroke and poststroke Barthel Index would have provided a more accurate depiction of recovery following thrombectomy in a population with preexisting functional impairment. Nonetheless, it remains conventional (and promotes generalizability of findings)³ to assign prestroke mRS scores for the time being.^4,5 While limited in scope, the prestroke mRS is widely used in selection of patients with stroke for interventional trials.

We respectfully disagree with the suggestion to code a patient with an mRS of 0 who has “returned to baseline” if their prestroke level of function was scored as a 3. Recovering to a prior level of disability can still be captured in absolute terms, and the mRS of 3 denotes this. Recoding as a “0” would convert the quantitative scale to a relative scale and may confound the findings.