SUBARACHNOID HEMORRHAGE
Endovascular treatment of cerebral aneurysm
Created 03/04/2021, last revision 30/09/2022
Coiling
- the most common procedure is coiling, where the sac is filled with detachable platinum coils → aneurysm gets thrombosed and thus removed from circulation
- coils vary in stiffness, filament diameter, shape, size, and length, or surface
- there are different 2D and 3D variants
- unbinding of the coils is performed electrolytically, hydraulically, or by the mechanical release of the guidewire
- using flow diverters and stent or balloon-assisted coiling extends the indications for coiling toward aneurysms with a wider neck (see below)

The endovascular procedure
- inform the patient about the planned procedure, its benefits, complications, and alternatives
- antiplatelet drugs are necessary if the use of a stent is expected
- before the procedure, introduce a Folley catheter and two intravenous cannulas
- coiling is usually performed in general anesthesia (GA)
- prevention of dangerous movements at critical moments of the procedure (risk of perforation of the artery)
- greater comfort for the patient and the surgeon
- easier management of complications
- TCD monitoring (detection of embolization in partially thrombosed aneurysms) is helpful
- HEPARIN 3000-5000jj i.v. is administered initially to reduce the risk of thromboembolism
- in recent SAH, use only 2000 IU, or administer heparin after the first coils have been applied to the aneurysm
- monitor APTT during the procedure; adjust the heparin dose
- prepare PROTAMIN in case of aneurysm rupture → see here
- access route
- usually via the femoral artery
- alternatively, radial, brachial, axillary, or rarely carotid artery are used
- guiding catheter and microcatheter must be flushed continuously with heparinized saline to prevent thrombus formation
- the first spiral must be stable; it creates a structure that is filled with other smaller spirals
- the decision to place the last coil is crucial:
- incomplete filling of the aneurysm increases the risk of aneurysm progression and rebleeding
- on the other hand, a redundant coil is difficult to insert and withdraw and may detach prematurely during retraction and slip into the parent artery
- after the procedure, the patient is admitted to the ICU for monitoring
Stent assisted coiling and other methods
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Complications of endovascular treatment
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Postprocedural medication
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Follow-up of coiled aneurysms
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Results of endovascular therapy
- the technical success of endovascular treatment is influenced by:
- experience of the interventional radiologist
- patient’s age and clinical condition
- presence of vasospasm or elongation and kinking of extracranial arteries
- experience of the interventional radiologist
- the disadvantage is lower stability of closure in large aneurysms, aneurysms with a wide neck, or in case of intra-saccular thrombosis
- in small aneurysms, complete occlusion is achieved in ~70-90%
- in large to giant aneurysms in ~ 50%
- incomplete occlusion leads to residual sac filling
- causes of incomplete occlusion:
- incomplete filling of the neck by coils
- compression of the coils before covering the neck with neointima
- insertion and displacement of the coils into the thrombus that was present inside the aneurysm during the procedure
- incomplete filling of the neck by coils
- incomplete closure is a risk factor for aneurysm expansion; endovascular treatment can be repeated and additional coils added to the sac