Efficacy and safety of heparin in preventing embolic events during transradial cerebral angiography: a randomised controlled trial

Background Transradial access has become an increasingly preferred approach for cerebral angiography. However, embolic events, often clinically silent, remain a frequent concern. Despite routine use, the efficacy and safety of heparin strategies in this setting lack randomised clinical trial evidence. Methods In this investigator-initiated, single-centre, prospective, open-label, outcome-blinded randomised clinical trial, adult patients undergoing transradial cerebral angiography with a negative diffusion-weighted imaging (DWI) scan within the past month were enrolled. Participants were randomised (1:1:1) to receive no heparin (heparin-free), systemic heparinisation alone or systemic heparinisation followed by continuous heparinised saline flush. A follow-up DWI was performed within 24 hours postprocedure to identify new ischaemic lesions. The primary efficacy outcome was the incidence of new embolic events. Safety outcomes included bleeding and other procedure-related adverse events. Results Between March and December 2024, 472 patients were randomised. Embolic events were detected in 24 of 158 patients (15.2%) in the heparin-free group, 24 of 157 patients (15.3%) in the heparinisation group (adjusted risk ratio (RR) 0.93; 95% CI 0.54 to 1.61; p=0.802) and 35 of 157 patients (22.3%) in the heparinisation followed by heparinised saline flush group (adjusted RR 1.22; 95% CI 0.74 to 2.03; p=0.437). Bleeding complications occurred in one (0.6%) patient in the heparin-free group, three (1.9%) patients in the heparinisation group and nine (5.7%) patients in the heparinisation followed by heparinised saline flush group (p=0.02). Overall adverse events were reported in two (1.3%), four (2.5%) and 11 (7.0%) patients across the respective groups (p=0.018). Conclusions Systemic heparinisation did not reduce embolic events, while continuous heparinised saline flush increased bleeding and adverse events without added benefit. These findings suggest that routine use of heparinised flush warrants reconsideration, emphasising the need to balance procedural anticoagulation strategies against safety risks in clinical practice. Trial registration number ChiCTR2400080902.