BackgroundTissue plasminogen activator (tPA) is an effective treatment for acute ischemic stroke. Although initial improvement is observed when administered for branch atheromatous disease (BAD), some cases subsequently worsen. Clinical data on the characteristics of these patients is lacking, and the benefits of tPA are unclear. ObjectiveTo analyze rebound cases and elucidate the clinical characteristics and outcomes associated with tPA administration in BAD. MethodsThis multicenter retrospective study was conducted in Japan. Worsening after initial improvement of a condition is termed as rebound, and such cases were compared with other types of ischemic stroke in patients with and without rebound. The characteristics of patients with BAD who rebounded were examined. ResultsThe study included 93 patients. Among the patients who were administered tPA, the NIHSS scores at 24 h and 7 days post-tPA were significantly higher in patients with BAD than in patients with other types of infarcts. The group with BAD exhibited a significantly higher rate of rebound than other groups (37.5 % vs. 0 %, P < 0.001). However, no differences were observed in outcomes between patients who experienced rebound after tPA administration and those who did not. ConclusionsReevaluation and changing the strategy of tPA use in patients with BAD may be necessary. However, this study does not totally discourage its use, as specific patients can benefit.