| Detachable Coil Embolization
What is Detachable Coil Embolization? Back to Top
Detachable
coil embolization offers a new approach to treating aneurysms and other
blood vessel malformations in the brain and other parts of the body. A
brain aneurysm, or weakness in the arterial wall, is a serious medical
condition. If a brain aneurysm ruptures, internal bleeding may cause a
stroke or loss of life. In less severe cases, a bulging aneurysm may
compress surrounding nerves and brain tissue resulting in nerve
paralysis, headache, neck and upper back pain as well as nausea and
vomiting. Cerebral angiography, computed tomography (CT) or magnetic
resonance (MR) imaging can detect brain aneurysms prior to rupturing.
Interventional neuroradiologists perform detachable coil
embolization to alleviate much of the danger presented by aneurysms.
The interventional neuroradiologist inserts a tube, called a catheter,
into an artery in the leg. This catheter is then maneuvered through the
body to the aneurysm's position. Once in position, the radiologist
places one or more small coils through the catheter into the aneurysm.
The body responds by forming a blood clot around the coil blocking off
the aneurysm.
Detachable coils may also be used to treat a rare intracranial
congenital vascular condition called arteriovenous malformation. In
this instance, the brain's arteries and veins are not connected by
normal capillaries but are linked instead by abnormal connections
called arteriovenous fistulas. These fistulas may empty the arteries of
blood before cerebral circulation is completed. This abnormal blood
exchange between cerebral arteries and veins may cause headaches,
hemorrhage, seizures and strokes, as well as neurological symptoms
impacting memory, movement, speech and vision.
Coils can be used either to block blood flow to the affected area or
to fill the aneurysm or fistula, thus preventing a rupture.
Occasionally, additional coils may be inserted during a subsequent
procedure to complete treatment.
Using detachable coils to close off the aneurysm or fistula is
effective in prolonging life and relieving symptoms. To minimize the
risk of rupture, researchers developed soft, detachable coils. Coil
embolization currently is used to treat approximately 30 percent of
cerebral aneurysms and 20 percent of arteriovenous malformations.
What are some common uses of the procedure? Back to Top
Coil
embolization is most frequently used to treat aneurysms and fistulas in
the brain where open surgery is risky. The coils prevent rupture and
further growth of the aneurysm or fistula by creating a blood clot to
close off blood flow to the affected area.
A variety of clinical and biological factors come into play when
identifying a candidate for detachable coil embolization. Physicians
consider the patient's age and health status as well as the position
and form or structure of the aneurysm and its relationship to
surrounding normal circulatory system structures. Young, healthy
patients respond well to this procedure. However, there are benefits
for older people as well. Coil embolization is especially useful for
patients who are unsuitable for brain surgery. This procedure is also
ideal for those seeking to avoid blood transfusion or general
anesthesia.
How should I prepare for the procedure? Back to Top
When CT
or MR imaging detects a brain aneurysm or arteriovenous malformation, a
cerebral angiogram may be necessary for diagnosis and treatment. During
this minimally invasive procedure, contrast material is injected into
the problem artery to allow x-ray visualization. Some procedures allow
the brain's vascular system to be displayed in three dimensions, which
makes diagnosis much easier.
What do the coils look like? Back to Top
There are three
types of detachable coils—bare platinum coils, coated platinum coils
and biologically active coils. All three types are made of soft
platinum wire of less than a hair's width. All detachable coils are
scientifically proven to be safe and effective and approved by the Food
and Drug Administration (FDA).
How does the procedure work? Back to Top
Plugging the weak,
bulging section of the artery or fistula stops blood flow to the
affected area and markedly decreases the risk of rupture. The coils are
designed to remain anchored within the aneurysm or fistula and do not
require eventual removal. Depending upon the size of the aneurysm,
coils of different diameters and lengths may be selected.
How is the procedure performed? Back to Top
Detachable coil
embolization is performed in the neurointerventional angiography unit
by an interventional neuroradiologist. An anesthesiologist is present
to closely monitor blood pressure, heart rate and rhythm and blood
oxygenation during the embolization procedure. The interventional
neuroradiologist delivers a catheter through a leg artery to the
aneurysm. The detachable coils are then inserted to fill the sac of the
aneurysm and/or block the arteriovenous fistula.
What will I experience during the procedure? Back to Top
The
procedure may take 30 minutes to four hours depending upon complexity.
Local or general anesthesia can be used for this procedure. Your
radiologist will help you decide which is best for you.
Patients undergoing local anesthesia will feel relaxed and sleepy
after the intravenous (IV) sedative is started. You may feel slight
pressure when the catheter is inserted but no serious discomfort.
Patients who receive general anesthesia will have no memory of the
procedure.
The severity of symptoms varies widely between ruptured and
unruptured aneurysms. Patients who had a stroke will have a more
difficult recovery and only 25 percent may be symptom-free after the
procedure. Recovery depends upon the brain damage from the bleeding.
Very sick patients with narrowed cerebral arteries following a ruptured
aneurysm may benefit from surgical brain manipulation.
Following endovascular treatment, bed rest will be required.
Patients who did not have a ruptured aneurysm prior to treatment may be
able to leave the hospital the day after the procedure. Stroke patients
should expect a post-procedure recovery in the neurosurgical intensive
care unit followed by a seven- to 10-day recovery on the neurosurgery
floor, and they may require sedation.
Following the procedure, patients may experience mild nausea and
low-grade fever. Headaches may last from seven days to six months.
However, headaches are often not a major issue for those with
unruptured aneurysms or fistulas. Following the procedure, follow-up
reviews of coil positioning may be completed using x-ray, MRI or
cerebral angiography. Aspirin or blood thinners may be prescribed.
Recovery time varies by patient. Most people are able to care for
themselves within 10 days to six months. Many patients return to work
after one month and begin driving at three months. Those with
unruptured aneurysms and fistulas typically recover within 24 hours.
Who interprets the results and how do I get them? Back to Top
The
interventional neuroradiologist will evaluate your procedure and
results and coordinate appropriate follow-up care with your primary
care physician.
What are the benefits vs. risks? Back to Top
Benefits
- Minimally invasive: Detachable coil embolization allows
treatment of cerebral aneurysms that previously were considered
inoperable. This procedure is less invasive and requires significantly
less recovery time than open surgery for aneurysm repair. Additional
benefits include minimal blood loss and the option of local anesthesia.
- Durable effect: Recurrence depends on the coils'
success or failure in controlling the "neck" of the aneurysm or
fistula. If the coil completely prevents blood flow into the aneurysm,
then the patient need not be concerned about recurrence. The durability
of coil embolization varies depending on the size and shape of the
aneurysm. Coil embolization of small aneurysms with small necks has
better results than embolization of large or giant aneurysms with wide
necks. Long-term follow-up has shown permanent success in more than 80
percent of aneurysms treated with coil embolization.
Risks
- Catheter-related risks: Intra-arterial catheterization
involves a risk of bleeding, infection and arterial damage. Experience
on the part of the interventional neuroradiologist coupled with good
infection control can help minimize these risks.
- Surgical
risks: As with any invasive procedure, there is a slight risk of death
or illness; however, coil embolization of unruptured aneurysms and
fistulas carries less risk than embolization following a stroke.
Approximately 7 percent of cases require additional treatment or
surgery.
What are the limitations of Detachable Coil Embolization? Back to Top
Aneurysms
are being treated with coil embolization more frequently due to the
incorporation of other medical technologies such as balloon assistance
and microstenting. Unfortunately, large aneurysms with wide necks
remain a challenge. Most neurosurgeons are knowledgeable about this
widely available procedure as are an increasing number of neurologists. Back to Top |
