Liping Huang,1,* Chen Gong,1,* Zhongming Qiu,2,* Shuyu Jiang,1,* Min Song,1,* Zhiyuan Wang,1 Yankun Chen,1 Tao Xu,1 Pan Hu,1 Shengli Chen,3 Yangmei Chen,1,4 Thanh N Nguyen,5 Chang Liu1 

1Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 2Department of Neurology, Xinqiao Hospital and The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, People’s Republic of China; 3Department of Neurology, Chongqing University Three Gorges Hospital, Chongqing, Wanzhou, People’s Republic of China; 4Key Laboratory of Major Brain Disease and Aging Research (Ministry of Education), Chongqing Medical University, Chongqing, People’s Republic of China; 5Department of Neurology, Boston Medical Center, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, USA

*These authors contributed equally to this work

Correspondence: Chang Liu, Department of Neurology, the Second Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China, Tel +8615696811121, Email liuchanghy@hospital.cqmu.edu.cn Thanh N Nguyen, Department of Neurology, Boston Medical Center, Boston University Chobanian and Avedisian School of Medicine, Boston, USA, Email Thanh.Nguyen@bmc.org

Purpose: Although the predictive role of cerebral tissue impairment has been extensively investigated in acute ischemic stroke (AIS) patients undergoing endovascular treatment (EVT) in the late window, the impact of peripheral organs on clinical outcomes in these patients remains largely unknown. Therefore, we aimed to explore whether frailty, a reflection of the patient’s physical status based on peripheral organ health at admission, could be associated with outcomes among AIS patients treated by EVT in the late window of 6– 24 hours from stroke onset.
Patients and Methods: This was a post-hoc analysis of our RESCUE-BT trial, with findings validated in an external cohort. The 5-factor modified frailty index (mFI-5), a scale of five factors that could reflect premorbid physical conditions, was applied to estimate frailty status. The primary outcome was functional independence, defined as a 90-day modified Rankin Scale (mRS) score of 0– 2.
Results: There were 755 patients included in this study. After identifying the cut-off value of mFI-5 by the marginal effects approach, patients were divided into the frail group (mFI-5≥ 2) and the non-frail group (mFI-5< 2). In multivariable analysis, frailty significantly reduced the likelihood of functional independence (aOR 0.37, 95% CI 0.21– 0.65, P< 0.001). Similar results were detected in the novel cohort constructed with propensity score matching (aOR 0.44, 95% CI 0.22– 0.85, P=0.015) and in the external validation cohort (aOR 0.38, 95% CI 0.16– 0.89, P=0.028). Moreover, frailty significantly improved the predictive performance of traditional predictors with an AUC of 0.77 (P=0.036 by DeLong’s test).
Conclusion: This study demonstrated that frailty according to the mFI-5 index was inversely associated with functional independence among AIS patients receiving EVT in the late window.

Keywords: ischemic stroke, endovascular treatment, late window, frailty, mFI-5