Endovascular treatments have become a mainstay for suitable aneurysms. Most aneurysms can now be treated by without the need to approach the aneurysm through an opening in the skull. In our practice these procedures are carried out by interventional neuroradiologists and not neurosurgeons.
Aneurysm Treatment Through the Bood Vessel
Coil Embolisation
The best established and most widely used endovascular treatment is called coiling. To begin with this was accomplished by deploying coils of platinum metal within the aneurysm dome. The coils are straight when mounted on a delivery wire but at the instigation of an electrical current they detach and conform to a 3 dimensional shape. The end result resembles a tiny ball of wire wool with the aneurysm.
This procedure does still require a general anaesthetic in almost all cases to ensure that the head remains absolutely still. A thin wire is passed though an artery in the groin or arm and navigated up through the main blood vessel of the body- the aorta. The wire travels past the heart, up through the blood vessels in the neck and into the arteries within the skull that deliver blood to the brain.
Coiling has proven a safe and robust treatment for most ruptured aneurysms in prospective randomised clinical trials. It has been our first-line treatment for ruptured aneurysms for more than twenty years now. It is not suitable for all aneurysms however. The shape or size of the aneurysm may dictate that a different endovascular technique (see below) or surgical repair is more advisable.
Occasionally the coil mass requires support to remain within the aneurysm and preventing blockage of the parent artery which could result in stroke. This may be temporarily accomplished with deployment of a small balloon during the procedure but if permanent support is required a metal stent can be deployed within th parent artery. This will mean than blood thinning antiplatelet medication is required for at least several months after the procedure.
Risks
The risks of coiling still include a usually small risk to life and risk of stroke in common with any other treatment for brain aneurysms. Bruising may develop at the site of the needle puncture and rarely injury to the artery through which the artery is accessed may require surgical repair. Your treating specialists will discuss such risks and any others as as they pertain to your individual case.
Follow-up
Coiled aneurysms require follow-up for several years to guard against aneurysm recurrence. This is usually carried out with MR angiography and begins with a scan at six months after the initial treatment. If the aneurysm is completely occluded at six months the chances are very good that it will not recur. In our practice we will continue follow-up for at least four years. Over time the tiny coil elements can get pushed together by the blood pressure and the coil "ball" is reduced in size allowing the aneurysm to potentially refill.
Filling into the centre of the coil mass seems to remain relatively protected against rupture. Blood flowing between the coil ball and the aneurysm wall though is concerning and further treatment usually recommended.
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Flow Diverting Stents
These represent an evolution in stent technology where the wall of the stent is more densely covered than those described above. As this density increases the stent serves to actively divert the flow of blood from an aneurysm into the parent artery as well as serving as physical support to a coil construct if used.
Such flow-diverting stents (FDS) may even be used without coiling the aneurysm so great is their ability to cause thrombosis within some aneurysms. In our practice to date however we have found it safest to combine them with coiling to make the aneurysm secure.
Over time it is anticipated that the stent will integrate into the wall of the blood vessel and become covered by the same cells found within a healthy artery.
Risks
As with other aneurysm treatments there is a risk to life during the procedure and a risk of stroke. The risks pertaining to your particular circumstances should be discussed with you by your treating specialists as well as any appropriate alternative approaches.
Over time it is anticipated that the stent will integrate into the wall of the blood vessel and become covered by the same cells found within a healthy artery. Until that occur though antiplatelt medication initially with aspirin and another agent is required to prevent clot developing within the stent risking stroke. There is currently variability in practice about how long such medication is required for. While required it renders an individual prone to bruising and rarely more serious bleeding.
Follow-up
Over time it is anticipated that the stent will integrate into the wall of the blood vessel and become covered by the same cells found within a healthy artery. Until that occurs though antiplatelt medication initially with aspirin and another agent is required to prevent clot developing within the stent risking stroke. There is currently variability in practice about how long such medication is required for.
As with other endovascular treatment imaging follow up in the medium term is advisable. Initially this may be with a procedure called an intravenous digital subtraction angiogram (IV-DSA) at about six months after the procedure. Thereafter MRI will usually be sufficient.
Intrasaccular Flow Disruptors
These are a family of endovascular devices originally intended to endovascularly treatwide necked aneurysms without the need to administer drugs to inhibit blood clotting. However as experienced as accrued with them use of an antiplatelet agent is often reccomended in the early stages after treatment. There are now various such devices marketed with more introduced constantly. Those currently in use for selected cases at our practice are the Wen Endobridge Device (WEB) and Contour devices.
This type of technology evolves rapidly and do allow treatment options for lesions that sometimes could not be safely treated by other means. However it requires time to be certain that new devices are safe and efficacious once in widespread use.
If a new device is being considered as part of your treatment at our practice we encourage you to ask questions of us. We will be happy to provide additional written information about novel devices and discuss alternative approaches. Where possible we look to introduce novel device in the context of a clinical trial or contribute data to registries. Of course you should always receive an informed, expert opinion about available alternatives.
