Endovascular coiling, also called coiling or endovascular embolization, is a procedure to block blood flow into an aneurysm (bulging, weak area in an artery wall). An aneurysm in the brain is also called a cerebral aneurysm, a brain aneurysm or an intracranial aneurysm.

Preventing blood from flowing into an aneurysm helps keep it from rupturing (bursting). Coiling is done to keep this from happening. In some cases, it is also done even if the aneurysm has already burst.

Coiling does not require surgery. Your doctor places a catheter (thin, hollow tube) in an artery in your groin, then moves it carefully up to the affected artery in your brain. X-rays are used to guide the catheter into the artery. A small medical device called a coil is placed in the aneurysm to stop blood from flowing into it.

Coiling may also be used to treat a condition called arteriovenous malformation, or AVM. An AVM is a group of abnormal blood vessels (arteries and veins) in the brain, spinal cord or elsewhere in the body.

The coils used in this procedure are made of soft platinum metal and shaped like a spring. They are very small and thin, ranging in size from about twice the width of a human hair (largest) to less than one hair's width (smallest).

If you have coiling, the doctor does not need to make an opening in your skull to reach the aneurysm. Your hospital stay and recovery time are often shorter. However, coiling is not the best treatment option for everyone with a cerebral aneurysm or AVM.

Coiling is done by a neurosurgeon (doctor who specializes in surgery on the brain and nervous system), an interventional radiologist (doctor who specializes in diagnosis and treatment using radiology) or both.


Other treatments for aneurysm

Aneurysms may be treated in different ways. This depends on:

  • The type of aneurysm
  • Where it is located in the brain
  • Your medical condition

The standard method for treating a cerebral aneurysm is called aneurysm clipping. In this procedure, your doctor makes an opening in your skull to reach the aneurysm in the brain. He or she uses a small metal clip to stop blood flow into the aneurysm. The clip looks like a clothespin. It is placed on the neck (opening) of the aneurysm to stop the flow of blood into it. The clip stays inside your brain after surgery.

Risks of coiling

Tell your doctor if you are pregnant or think you may be pregnant.

There is a risk for allergic reaction to the dye used in the coiling procedure. If you are allergic or sensitive to any medications, contrast dye or iodine, tell a member of your healthcare team. If you have kidney failure or other kidney problems, tell your radiologist before the procedure.

If you take anticoagulant (blood-thinning) medications such as aspirin, warfarin (Coumadin), clopidogrel (Plavix) or others, tell your doctor before the procedure. You can stop this medication for one or more days before having coiling.

Because the coiling procedure involves the blood vessels and blood flow of the brain, there is a risk for brain complications. These include, but are not limited to:

  • Loss of consciousness
  • Transient ischemic attack (TIA or "mini-stroke")
  • Hemiplegia (paralysis of half of the body)
  • Embolus (clot in the blood vessel)
  • Hemorrhage (bleeding)
  • Hematoma (an area of swelling caused by a collection of blood)
  • Stroke Aphasia (loss of the ability to speak or understand speech)
  • Infection
  • Rupture of previously unruptured aneurysm

There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your doctor before the procedure.

Before the procedure

Your doctor explains the coiling procedure to you, and you can ask any questions you have. We ask you to sign a consent form giving us permission to do the procedure. Please read the form carefully and ask a member of your healthcare team if you don't understand something.

Tell a member of your healthcare team if you have ever had a reaction to any contrast dye or are allergic to:

  • Iodine
  • Any medications
  • Latex
  • Tape
  • Any anesthesia (local or general)

Before the procedure, you need to fast (go without eating or drinking) for a certain time. Your doctor will tell you whether you should fast a few hours or overnight before the procedure.

If you are pregnant or think you may be pregnant, tell your doctor. Tell your doctor about all medications you take, including prescription and over-the-counter (non-prescription) medications and any herbal supplements or vitamins. Tell your doctor if you have a history of bleeding disorders or are taking any anticoagulant (blood-thinning) medications, aspirin or other medications that affect blood clotting. You may need to stop these medications before the procedure. Your doctor may do a blood test before the procedure to determine how long it takes your blood to clot. You might also have other blood tests.

During the procedure

If you have a coiling procedure, you stay in t he hospital overnight. How long you stay in the hospital depends on several factors, including:

  • Your brain or stroke condition
  • Your general health
  • How you respond to the procedure
  • Your doctor's decisions about your condition and treatment
  • Other factors

You usually have coiling under general anesthesia (you're asleep and don't remember the procedure when you wake up). Some people have the procedure with local anesthesia and sedation (numbing medicine and medicine to make you relax and minimize discomfort). Talk to your doctor about the best option for you.

  1. Before the procedure, we ask you to remove any clothing, jewelry, hairpins, dentures or other objects that may interfere with the procedure. You wear a hospital gown. We remind you to empty your bladder (use the bathroom) before the procedure starts.
  2. You lie on your back on an X-ray table with an intravenous (IV) line in your hand or arm. You are connected to an EKG monitor that records the electrical activity of your heart during the procedure using small, adhesive electrodes. Your vital signs (heart rate, blood pressure and breathing rate) and neurological signs are monitored during the procedure. You have a catheter (thin, hollow tube) in your bladder to drain urine.
  3. Your doctor checks your pulses in the area where the catheter will be inserted and marks them with a marker. After the procedure, your healthcare team will check for these pulses to make sure you have normal circulation to your leg.
  4. The skin over the injection site is cleaned and a local anesthetic (numbing medicine) is injected. Your doctor makes a small incision (cut) in the skin to reach your artery. A catheter (thin, hollow tube) is placed in the artery in your groin and guided through the blood vessel into the brain. Your doctor uses an X-ray to guide the catheter.
  5. Once the catheter reaches the affected artery in your brain, contrast dye is injected to make the aneurysm and blood vessels around it visible on X-ray. The aneurysm is measured and its shape and other characteristics are determined and recorded. Once your doctor has enough information about the aneurysm, a microcatheter (smaller catheter) is placed in the first catheter. A coil is attached to the microcatheter, and an X-ray is used to make sure the catheter is in the right place inside your body.
  6. When the microcatheter reaches the aneurysm, your doctor places the coil in the aneurysm. When the coil is completely inserted, a small electrical current is used to separate the coil from the catheter. Your doctor puts in as many coils as needed to completely seal off the aneurysm. The coils form a mesh-like structure inside the aneurysm. After the aneurysm is filled with coils, additional X-rays are taken to make sure the aneurysm is sealed off.
  7. Once the aneurysm is sealed off, the catheter is removed. To prevent bleeding, the insertion site may be closed with a device that uses collagen (a biological substance) to seal the opening. It can also be closed with stitches or by hand pressure on the area. Your doctor chooses the best option for you. The insertion site is bandaged, and your healthcare team may place a small sandbag or bag of fluid over the bandage to prevent bleeding.

After the procedure

After the procedure, you go to the recovery room or the intensive care unit (ICU) for observation, depending on your particular situation. If the coiling procedure was performed for a ruptured aneurysm, you usually go to the ICU for recovery and observation. If your aneurysm was not ruptured and your condition is otherwise stable, you may go home a day or two after the procedure.

You lie flat in bed for as long as 12 to 24 hours after the procedure. A nurse will monitor your vital signs, the insertion site and your blood circulation and sensation (feeling) in the affected leg or arm. You may be given pain medication for pain or discomfort from the procedure or from having to lie flat and still for a long time. You can eat normally after the procedure unless your doctor tells you differently. Once you have recovered in the hospital, you usually go home. If you had a ruptured aneurysm, you might go to a rehabilitation facility to continue recovering from damage caused by the rupture.

At home

Your doctor will tell you when you can return to work and other normal activities. Immediately after the procedure, you might need to avoid vigorous activity. Ask your doctor or OHSU Stroke Center team member which activities are safe after a coiling procedure.

Call your doctor if you have:

  • Fever or chills
  • Increased pain, redness, swelling or bleeding or other fluid draining from the insertion site
  • Coolness, numbness or tingling or other changes in the leg or arm used in the procedure
  • Any changes in bodily functions or neurological changes, such as extreme headache, seizure or loss of consciousness

You usually have a cerebral angiogram (X-ray examination of blood vessels in your skull) at certain times after the coiling procedure. This tells your doctor how well the coils are working. You may have the first angiogram about one month after the procedure, and additional cerebral angiograms or other imaging scans later. Your OHSU Stroke Center doctor will talk with you about how often you need these imaging tests.

More information about coiling

The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your physician. Please consult your physician with any questions or concerns you may have regarding your condition.

This page contains links to other websites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these websites, nor do these sites endorse the information contained here.

American Association of Neurological Surgeons

American Stroke Association

Brain Aneurysm Foundation

National Institute of Neurological Disorders and Stroke

National Institutes of Health (NIH)

National Library of Medicine

National Stroke Association