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.
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.
The risks of coiling include a small risk to life and risk of stroke in common with any 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.
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 may get pushed together by the blood pressure and the coil "ball" is reduced in size allowing the aneurysm to potentially to 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.
After an uncomplicated coiling blood thinning medication is usually not required. However if some element of the coils mass projects into the normal path of blood flow an agent such as aspirin may be prescribed.
Stents are tiny metal tubes that may be deployed within blood vessels. They are used to prevent an coil ball from falling into the path of passing blood risking blockage of a blood vessel and resulting stroke. They are also used to hold blood vessels open where they have become narrowed and may be used to snare and retrieve blood clots within arteries.
Ultimately it is hoped that a stent will be incorporated into a blood vessel wall and covered by the cells which normally form the inner lining of healthy arteries. They are however foreign bodies that provoke blood clotting and therefore require that the patient take blood thinning medication at the time of their insertion. The requirement of a stent to support an aneurysm coiling increases the risk of complication slightly and introduces the risk of bleeding complications into the brain itself or in the pelvis and abdomen because of the need to impair the bloods ability to form clots. The benefits of the stent requires balancing against the need and the possible alternatives that might be condsidered.
These are a newer 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 divert the flow of blood from an aneurysm into the parent artery , not only serving as a physical support to a coil construct. 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.
There are similar risks to open cell stents. Treatment with two types of anti-platelet medication is recommended before implantation and this is continued for a period after treatment before reverting to a single agent if safe to do so. as with any treatment for aneurysms there is a risk to life and of stroke. The decision to deploy such a device is made jointly with specialist interventional neuroadiologists as part of a multi-disciplinary team in this practice. Again you will be fully appraised of avaialble alternatives if such treatment is considered.
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. Those currently in use for selected cases at our practice are the 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 novel device is being considered as part of your treatment in 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 devices 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.