Clinical outcomes following a hospital-wide transition from enoxaparin to tinzaparin for venous thromboembolism prophylaxis in neurosurgical patients

Abstract Objective Venous thromboembolism (VTE) prophylaxis is a key component of neurosurgical care, with low-molecular-weight heparins (LMWHs) representing the standard pharmacological approach. While enoxaparin is well established, the evidence regarding the efficacy and safety of tinzaparin in neurosurgical patients remains limited. This study aimed to compare the incidence of VTE and postoperative rebleeding between enoxaparin and tinzaparin in a large cohort of neurosurgical patients. Methods Following a standardized institutional switch from enoxaparin to tinzaparin in 2021, we conducted a retrospective cohort study including all adult patients undergoing neurosurgical procedures during the 2.5-year periods before and after the change. Patients were stratified according to their perioperative VTE risk. The primary outcome was imaging-confirmed symptomatic VTE during hospitalization, and the secondary outcome was postoperative rebleeding requiring surgical evacuation. A multivariable logistic regression analysis was performed to adjust for potential confounders. Results A total of 4,888 patients were included. Overall, 51 symptomatic VTE events occurred (1.04%). In low risk patients (Group A), VTE incidence did not differ significantly between enoxaparin and tinzaparin (0.44% vs. 0.86%, p = 0.35). In moderate-to-high risk patients (Group B), VTE occurred significantly more frequently with tinzaparin than enoxaparin (1.67% vs. 0.84%, p = 0.04), driven predominantly by PE (1.05% vs. 0.18%, p = 0.01), while DVT rates were comparable (0.62% vs. 0.67%, p = 0.87). Multivariable analysis in Group B confirmed lower odds of VTE with enoxaparin (OR 0.475, 95% CI 0.246–0.919, p = 0.027). Postoperative rebleeding rates did not differ significantly between treatment groups. The increase in PE coincided with increased CTA utilization and showed no clear temporal step change following the switch to tinzaparin. Conclusion Both enoxaparin and tinzaparin were associated with low VTE rates and comparable postoperative rebleeding rates. Although higher VTE rates with tinzaparin were observed in the medium-to-high risk group, the predominance of PE, increased CTA utilization, and absence of a temporal step change limit a causal interpretation. These findings should therefore be considered hypothesis-generating rather than evidence of superior efficacy of either agent.