Enhancing Cardiopulmonary Function Through Spasticity Reduction-Effects of Botulinum Toxin A After Stroke: A...

Background and Objectives: Post-stroke spasticity is a frequent complication that contributes to impaired mobility, reduced functional independence, and decreased exercise tolerance. While botulinum toxin A (BoNT-A) is widely used to improve muscle tone, its effects on cardiopulmonary exercise capacity remain insufficiently characterized. This study aimed to evaluate the impact of BoNT-A treatment on cardiopulmonary performance and functional outcomes in patients with post-stroke spasticity. Materials and Methods: A prospective before-after study was conducted including 50 patients with post-stroke spasticity. Cardiopulmonary exercise testing was performed before and after BoNT-A administration. The primary outcome was peak oxygen consumption (VO₂ peak), while secondary outcomes included anaerobic threshold (AT), exercise duration, maximal workload, 10 m walk test time, Barthel Index, and modified Rankin Scale (mRS). Paired comparisons and multivariable linear regression analyses were performed to assess changes and associated factors. Results: VO₂ peak increased significantly following treatment (12.96 ± 2.70 vs. 13.55 ± 2.85 mL/kg/min; mean change 0.59 mL/kg/min, 95% CI 0.36-0.82; p < 0.001). Similar improvements were observed for AT (10.47 ± 2.77 vs. 10.97 ± 2.97 mL/kg/min; p < 0.001), exercise duration (6.70 ± 1.48 vs. 7.11 ± 1.55 min; p < 0.001), and maximal workload (44.70 ± 10.97 vs. 48.06 ± 12.60 W; p < 0.001). Functional performance improved, as indicated by reduced 10 m walk time (18.33 ± 4.67 vs. 17.36 ± 4.82 s; p < 0.001) and increased Barthel Index (57.62 ± 19.18 vs. 61.92 ± 21.10; p < 0.001). A modest but significant reduction in disability was observed on the mRS (p = 0.003). Baseline values were the strongest predictors of post-treatment outcomes, while smoking status was associated with worse walking performance. Conclusions: BoNT-A treatment was associated with modest but consistent improvements in cardiopulmonary exercise capacity and functional performance in patients with post-stroke spasticity. These findings suggest that spasticity management may be associated with functional and exercise-related benefits extending beyond local neuromuscular effects, although causal relationships cannot be established based on the present study design. Further controlled studies are needed to confirm these findings and evaluate their long-term clinical significance.