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
  • the use of flow diverters and stent or balloon-assisted coiling extends the indications for coiling toward aneurysms with a wider neck (see below)
Aneurysm coiling

The endovascular procedure

  • inform the patient about the planned procedure, its benefits, complications, and alternatives
  • antiplatelet drugs are necessary if the use of stent is expected
  • before the procedure, introduce 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, according to the result, adjust the heparin dose
    • prepare PROTAMIN in case of aneurysm rupture → see here
  • access route
    • usually via 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
  • 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
The course of aneurysm sac embolization with coils
Aneurysm coiling
ACoA aneurysm embolisation

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
  • the disadvantage is lower stability of closure in large aneurysms, aneurysms with a wide neck, or in case of intra-saccular thrombosis Intrasaccular thrombosis in MCA aneurysm
    • 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 closure is a risk factor for aneurysm expansion; endovascular treatment can be repeated and additional coils added to the sac   An incomplete closure of the sac after initial embolization, complete closure after repeated procedure (righ image)
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