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

INTERVENTION: 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. CONDITION: Intracranial Aneurysm Intracranial Lesions PRIMARY OUTCOME: The primary outcome will be achievement of therapeutic range as assessed by APTT (UFH) or anti Xa (LMWH) testing ; ; Patients will be categorized in a binary fashion – either being within the therapeutic range or being sub/supratherapeutic. SECONDARY OUTCOME: Secondary outcome 1: The frequency of thromboembolic complications (either symptomatic or asymptomatic) in post‐operative intracranial aneurysm coiling, including stent or balloon assisted coiling within the first 24‐48 hours after cessation of intraoperative heparin, as assessed by neurological examination and pre‐ / post‐ procedure MRI Secondary Outcome 2: The frequency of hemorrhagic complications in post‐operative intracranial aneurysm coiling, including stent or balloon assisted coiling within the first 24‐48 hours after cessation of intraoperative heparin, as assessed by neurological examination and pre‐ / post‐ procedure MRI INCLUSION CRITERIA: Patients admitted for elective endovascular treatment of intracranial aneurysm are eligible for inclusion. Participants should understand the project and provide voluntary consent Eligible patients will be admitted to the study if at the end of the endovascular procedure the operator determines that a period of post procedural anticoagulation is clinically indicated. The 3 most common reasons for this are: 1) Placement of an indwelling endovascular device, such as a stent 2) Presence of procedural platelet aggregation 3) Perceived increased risk of thromboembolic events due to (3a) large area of coil exposure at aneurysm neck (3b) loop protrusion into parent artery