Comparison of two drug thinning agents (unfractionated heparin and low-molecular weight heparin) for prevention of stroke after brain aneurysm treatment utilizing coils or stents

Endovascular treatment of intracranial aneurysm with coils and stents requires procedural anticoagulation, most commonly with unfractionated intravenous heparin (UFH). Where the risk of thromboembolic complications is high (eg post stenting) heparinisation is continued for 24-48hrs post treatment. Post-procedural anticoagulation regimes aim for ‘therapeutic range’ based on repeated laboratory testing of sampled blood. In practice this can be difficult to achieve with consistency using UFH. Low molecular weight heparin (LMWH) offers some theoretical advantages over UFH but there is no published data on its use in neurointervention. We propose to compare post-procedural anticoagulation using UFH with LMWH (enoxaparin) in patients treated electively for intracranial aneurysms. Patients who meet entry criteria will be randomised to one of three regimes: a) UFH - continuous IV infusion, titrated by APTT test results (current standard of care) b) LMWH given as a single dose of 1.5mg/kg by subcutaneous injection at the end of the procedure c) LMWH given 1.0mg/kg by subcutaneous injection at the end of the procedure and at 12hours. The primary outcome will be achievement of therapeutic range as assessed by APTT (UFH) or anti Xa (LMWH) testing. The secondary outcome will be development of a clinically evident thromboembolic event (CETE) or a clinically silent lesion, either ischaemic (CSIL) or hemorrhagic (CSHL), assessed by neurological examination at 24 hours and MRI at 48hrs.