Reader Response: Prestroke Disability and Outcome After Thrombectomy for Emergent Anterior Circulation Large Vessel Occlusion Stroke
James E.Siegler, Neurologist, Cooper Neurological Institute
NicholasVigilante, Medical Student, Cooper Medical School of Rowan University
Submitted September 28, 2021
We applaud the TRACK Registry investigators for their evaluation of outcomes following thrombectomy in patients with pre-stroke disability.1
While we strongly agree with the investigators that patients with pre-existing disability will benefit more from endovascular therapy than they otherwise would from medical management, we are curious as to why the investigators selected the primary outcome of accumulated disability. For a condition in which patients are more likely to have long-term disability (modified Rankin Score >2) than to regain functional independence—despite thrombectomy—assessing for zero functional decline introduces an outcome misclassification bias that preferentially favors patients with pre-stroke disability.2 The reference to the “ceiling effect” of higher mRS levels among the exposure was appropriate and likely overestimates the beneficial effect of thrombectomy among patients with pre-stroke disability, when compared to patients without disability.
At a glance, these results suggest patients without pre-stroke disability benefit less from thrombectomy. These conclusions should be cautioned, particularly as patients with pre-stroke disability were nearly three times more likely to die at 90 days. A more lenient, composite outcome using the mRS, such as a lack of accumulated disability or mRS 0-2, or another metric might be more suited for evaluating efficacy of thrombectomy according to pre-existing disability.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References
de Havenon A, Castonguay A, Nogueira R, et al. Prestroke Disability and Outcome After Thrombectomy for Emergent Anterior Circulation Large Vessel Occlusion Stroke [published online ahead of print, 2021 Sep 20]. Neurology. 2021;10.1212/WNL.0000000000012827.
Albers GW, Lansberg MG, Brown S, et al. Assessment of Optimal Patient Selection for Endovascular Thrombectomy Beyond 6 Hours After Symptom Onset: A Pooled Analysis of the AURORA Database [published correction appears in JAMA Neurol. 2021 Sep 1;78(9):1154]. JAMA Neurol. 2021;78(9):1064-1071. doi:10.1001/jamaneurol.2021.2319
We applaud the TRACK Registry investigators for their evaluation of outcomes following thrombectomy in patients with pre-stroke disability.1
While we strongly agree with the investigators that patients with pre-existing disability will benefit more from endovascular therapy than they otherwise would from medical management, we are curious as to why the investigators selected the primary outcome of accumulated disability. For a condition in which patients are more likely to have long-term disability (modified Rankin Score >2) than to regain functional independence—despite thrombectomy—assessing for zero functional decline introduces an outcome misclassification bias that preferentially favors patients with pre-stroke disability.2 The reference to the “ceiling effect” of higher mRS levels among the exposure was appropriate and likely overestimates the beneficial effect of thrombectomy among patients with pre-stroke disability, when compared to patients without disability.
At a glance, these results suggest patients without pre-stroke disability benefit less from thrombectomy. These conclusions should be cautioned, particularly as patients with pre-stroke disability were nearly three times more likely to die at 90 days. A more lenient, composite outcome using the mRS, such as a lack of accumulated disability or mRS 0-2, or another metric might be more suited for evaluating efficacy of thrombectomy according to pre-existing disability.
Disclosure
The authors report no relevant disclosures. Contact journal@neurology.org for full disclosures.
References