Risk factors and intervention strategies for lower extremity deep vein thrombosis after intravenous thrombolysis for acute ischemic stroke.

Objective: This study examined the association between absence of early pharmacological thromboprophylaxis and in-hospital DVT after IVT for AIS, and further explored the clinical characteristics associated with failure to initiate timely prophylaxis. Methods: We conducted a single-center retrospective cohort study of 197 patients with AIS treated with IVT between January 2021 and April 2024. Early pharmacological thromboprophylaxis was defined as anticoagulant prophylaxis initiated within 24-48 h after IVT after repeat neuroimaging excluded intracranial hemorrhage. The primary outcome was in-hospital lower extremity DVT confirmed by venous ultrasonography. Multivariable logistic regression was used to identify factors associated with non-initiation of early prophylaxis and to examine the association between absence of early prophylaxis and DVT. Results: Among 197 patients, 118 (59.9%) received early prophylaxis and 79 (40.1%) did not. Overall, 32 patients (16.2%) developed in-hospital DVT. DVT occurred more frequently in patients without early prophylaxis than in those receiving early prophylaxis (30.4% vs. 6.8%, Conclusions: Among patients with AIS treated with IVT, absence of early pharmacological thromboprophylaxis was associated with higher odds of in-hospital DVT. Notably, a risk-treatment paradox was observed: patients with higher baseline thrombotic risk (e.g., severe stroke, atrial fibrillation, elevated D-dimer) were less likely to receive early prophylaxis, presumably due to concerns about post-thrombolysis hemorrhagic transformation. These findings suggest a clinically relevant prevention gap, although the observed association should be interpreted cautiously given the retrospective design and non-randomized treatment allocation.