ObjectiveWe aim to assess the incidence and impact of in-hospital medical complications (MCs) on clinical outcomes in acute ischemic stroke (AIS) patients after endovascular therapy (EVT). MethodsAIS patients who underwent EVT were consecutively recruited from January 2019 to July 2022. The primary outcome was a poor 3-month functional outcome, defined as a modified Rankin Scale score (mRS) of 3-6. The safety variables were symptomatic intracerebral hemorrhage (sICH) and mortality at seven and 30 days. ResultsA total of 306 (50.1%) patients experienced at least one of the MCs. The most common MC was pneumonia (42.6%). Multivariate analysis revealed that the setting of MCs was an independent predictor of a poor 3-month functional outcome (adjusted odds ratio [aOR] 4.40, 95% confidence interval [CI] 3.01-6.42; P<0.001). In the subgroup analysis, this trend was significant, especially in the patients aged 60 to75 years (aOR 5.87, 95% CI 3.45-9.97; P<0.001) or with baseline NIHSS (≤16) (aOR 5.05, 95% CI 2.84-9.01; P<0.001). For individuals, cardiac events (aOR 8.56, 95% CI 4.05-18.09; P<0.001), pneumonia (aOR 5.08, 95%CI 3.42-7.55; P<0.001), and gastrointestinal bleeding (GIB) (aOR 6.12, 95%CI 3.40-11.01; P<0.001) were independently associated with the poor 3-month outcome. The setting of MCs was independently associated with sICH (aOR 2.11, 95% CI 1.22-3.64; P=0.007) and mortality at 30 days (aOR 2.11, 95% CI 1.22-3.64; P=0.007) after adjustment, but not with mortality at seven days. ConclusionsMCs in AIS patients after EVT have a high incidence, despite successful reperfusion, adversely affecting clinical outcomes and increasing short-term mortality.