Periprocedural unfractionated heparin bolus during endovascular treatment in acute ischemic stroke does more harm than good

Background Unfractionated heparin (UFH) bolus is occasionally administered during endovascular treatment (EVT) to reduce thrombotic complications in acute ischemic stroke patients. However, the MR CLEAN-MED trial showed an increase in symptomatic intracranial hemorrhages (sICH) and a non-significant shift towards worse functional outcome with UFH administration. We aimed to analyze the impact of periprocedural UFH bolus in a real-world setting in anterior (ACS) and posterior circulation stroke (PCS) patients. Methods We analyzed data from the German Stroke Registry-Endovascular Treatment using propensity score matching. Primary outcome was the modified Rankin Scale at 3 months, and secondary outcome measures included mortality, angiographic outcomes, post-EVT National Institute of Health Stroke Scale scores and ICH at 24 hours. Results Among 13,082 patients, 7948 with ACS (UFH bolus use in 15%) and 841 with PCS (UFH bolus use in 16.3%) were included in the propensity score matching analysis. Applying MR CLEAN-MED study criteria, UFH bolus was associated with worse functional outcomes (odds ratio [OR] 1.44; 95% CI 1.06–1.96). Analyzing all ACS and PCS patients, UFH bolus did not provide any net benefit. In ACS patients treated with intravenous thrombolysis (IVT), UFH bolus use was associated with worse functional outcomes (OR 2.40; 95% CI 1.34 to 5.06). Conclusion Our findings show transferability of the MR CLEAN-MED results into a real-world setting, confirming a negative effect of periprocedural UFH on functional outcome in this subgroup of patients. Considering all ACS and PCS patients, periprocedural UFH did not provide a net benefit and appears to be harmful, particularly in IVT-treated patients.