Seven-Day Modified Rankin Scale Score as an Early Predictor of 90-Day Functional Outcome After Mechanical Thrombectomy.

Abstract

Purpose: We hypothesized that the modified Rankin Scale (mRS) score after mechanical thrombectomy (MT) could predict subsequent functional improvement.

Methods: We retrospectively analyzed consecutive patients with acute ischemic stroke who underwent MT at our institution between January 2020 and December 2024. The association between the 7‑day and 90-day mRS scores was evaluated in all eligible patients (N = 432). Analyses of functional improvement were performed in patients with a 7-day mRS score of 3-5 (n = 290). Functional improvement was defined as a decrease of ≥ 1 point in the mRS score from day 7 to day 90, and patients were classified into improvement and non-improvement groups.

Results: There was a strong correlation between the 7‑day and 90-day mRS scores (r = 0.86), with moderate agreement (weighted κ = 0.48). Functional improvement was observed in 95 (32.8%) of 290 patients with a 7-day mRS score of 3-5. Compared with the non-improvement group, the improvement group was significantly younger (median age, 79 versus 84 years; P < 0.0001), had a higher proportion of prestroke mRS score of 0-2 (82.1% versus 58.0%; P < 0.0001), and a higher prevalence of current smoking (17.9% versus 6.7%; P = 0.003). In multivariable logistic regression analysis, younger age (OR 0.96 per 1‑year increase; 95% CI, 0.93-0.99; P = 0.0030) and a prestroke mRS score of 0-2 (OR 2.7; 95% CI, 1.42-4.98; P = 0.0023) were identified as independent predictors of functional improvement.

Conclusions: The 7‑day mRS score after MT was strongly associated with the 90-day mRS score. Among patients with a 7-day mRS score of 3-5, younger age and a prestroke mRS score of 0-2 were independent predictors of functional improvement.