Endovascular Coiling

What is endovascular coiling?

Healthcare providers use endovascular coiling, a form of endovascular embolization, to block blood flow into an aneurysm. An aneurysm is a weakened area in the wall of an artery. If an aneurysm ruptures, it can cause life-threatening bleeding and brain damage. Preventing blood flow into an aneurysm helps to keep it from rupturing.


For endovascular coiling, healthcare providers use a catheter, a long, thin tube inserted into a groin artery. The catheter is advanced into the affected brain artery where the coil is deployed. X-rays help guide the catheter into the artery. The coils are made of soft platinum metal, and are shaped like a spring. These coils are very small and thin, ranging in size from about twice the width of a human hair to less than one hair's width.

Healthcare providers also use coiling to treat a condition called arteriovenous malformation, or AVM. An AVM is an abnormal connection between an artery and a vein. It may happen in the brain, spinal cord, or elsewhere in the body.

Why might I need endovascular coiling?

Healthcare providers most commonly use coiling to treat a cerebral aneurysm at risk for rupturing. In some cases, they may use it to repair a ruptured aneurysm.

There may be other reasons for your healthcare provider to recommend a coiling procedure.

What are the risks of endovascular coiling?

If you are pregnant or think you may be pregnant, you should tell your healthcare provider.

There is a risk for allergic reaction to the dye injected to allow the aneurysm to be viewed on X-ray. People who are allergic to or sensitive to medicines, contrast dye, or iodine should tell the radiologist or technologist. People with kidney failure or other kidney problems should tell the radiologist.

People who take anticoagulant (blood-thinning) medicines, such as aspirin, warfarin, clopidogrel, or others, should tell their healthcare providers before the procedure. These medicines may be stopped for one or more days before the procedure.

Because the procedure involves the blood vessels and blood flow of the brain, there is a risk for complications involving the brain. These complications may include:

  • Loss of consciousness
  • Stroke or transient ischemic attack (TIA, a temporary stroke-like condition)
  • Paralysis of one half of the body
  • Blood clot
  • Bleeding
  • An area of swelling caused by a collection of blood (hematoma)
  • Loss of the ability or speak or the ability to understand speech (aphasia)
  • Infection
  • Rupture of unruptured aneurysm
  • Higher chance of an aneurysm recurring

There may be other risks depending on your specific medical condition. Discuss any concerns with your healthcare provider before the procedure.

How do I get ready for an endovascular coiling?

  • Your healthcare provider will tell you about the procedure and offer you a chance to ask any questions.
  • You will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.
  • Tell your healthcare provider if you have ever had a reaction to any contrast dye, or if you are allergic to iodine.
  • Tell your healthcare provider if you are sensitive to or are allergic to any medicines, latex, tape, or anesthetic agents (local and general).
  • You will need to fast for a certain period before the procedure. Your healthcare provider will tell you how long to fast, whether for a few hours or overnight.
  • Tell your healthcare provider if you are pregnant or think you may be pregnant.
  • Tell your healthcare provider of all medicines (prescribed and over-the-counter) and herbal supplements that you are taking.
  • Tell your healthcare provider if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medicines, aspirin, or other medicines that affect blood clotting. It may be necessary for you to stop these medicines before the procedure.
  • Your healthcare provider may request a blood test before the procedure to determine how long it takes your blood to clot. Other blood tests may be done as well.
  • Based on your medical condition, your healthcare provider may request other specific preparation.

What happens during an endovascular coiling?

You will need to stay in the hospital for a coiling procedure. Procedures may vary depending on your condition and your healthcare provider's practices.

Your procedure may be done by one or both of these specialists:

  • Neurosurgeon. This healthcare provider specializes in surgery and treatment of the nervous system
  • Interventional radiologist. This healthcare provider specializes in diagnostic and treatment methods using radiology techniques.

During the procedure, you are asleep under general anesthesia. In some situations, it may be done under local anesthesia.

Generally, a coiling procedure follows this process:

  • You will be asked to remove any clothing, jewelry, hairpins, dentures, or other objects that may interfere with the procedure, and will be given a hospital gown to wear.
  • You will be given time to empty your bladder prior to the start of the procedure.
  • You will be positioned on your back on the X-ray table.
  • An intravenous (IV) line will be started in your hand or arm.
  • You will be connected to an electrocardiogram (ECG) monitor that records the electrical activity of the heart. Your vital signs (heart rate, blood pressure, and breathing rate) and neurological signs will be monitored during the procedure.
  • A catheter may be inserted into your bladder to drain urine.
  • The radiologist or neurosurgeon will check your pulses below the groin site where the catheter will be inserted and mark them with a marker so that the circulation to the limb below the site can be checked after the procedure.
  • The skin over the injection site will be cleansed. A local anesthetic will be injected.
  • A small incision will be made in the skin to expose the artery in the groin.
  • A catheter will be inserted into the artery in your groin using a guide wire. The catheter will be guided through the blood vessel into the brain using fluoroscopy (a special type of X-ray, similar to an X-ray "movie").
  • Once the catheter has been guided to the affected artery in the brain, contrast dye will be injected to make the aneurysm and surrounding blood vessels visible on X-ray.
  • The aneurysm will be measured and its shape and other characteristics will be recorded.
  • Next, a smaller catheter will be inserted into the initial catheter.
  • Once the catheter has reached the aneurysm, the healthcare provider will manipulate the coil into the aneurysm.
  • When the coil has been completely inserted into the aneurysm, the coil is separated from the catheter.
  • The healthcare provider will insert as many coils as needed to completely seal off the aneurysm. The coils will form a mesh-like structure inside the aneurysm.
  • After the aneurysm has been "packed" with coils, additional X-ray images will be taken to make sure the aneurysm has been sealed off. The coil is left in place permanently in the aneurysm.
  • Once the aneurysm has been sealed off, the catheter will be removed. After the insertion site stops bleeding, a dressing will be applied.

What happens after an endovascular coiling?

In the hospital

After the procedure, you may be taken to the recovery room or the intensive care unit (ICU) for observation. If the coiling procedure was done for a ruptured aneurysm, you will most likely be taken to the ICU for recovery and observation. If the coiling procedure was done for an unruptured aneurysm and your condition is otherwise stable, you may be able to go home a day or two after the procedure.

You will remain flat in bed for as long as 12 to 24 hours after the procedure. A nurse will monitor your vital signs, neurological signs, the insertion site, and circulation or sensation in the affected leg.

You may be given pain medicine for pain or discomfort from the procedure or from having to lie flat and still for a prolonged period.

You may resume your usual diet after the procedure, unless your healthcare provider decides otherwise.

Once you have recovered, you may be able to go home, unless your healthcare provider decides otherwise. In some cases, after a procedure for a ruptured aneurysm, a transfer to a rehabilitation facility may be necessary to help continue recovery from damage that may have happened as a result of the ruptured aneurysm.

At home

You may be advised not to do any strenuous activities. Your healthcare provider will instruct you about when you can return to work and resume normal activities. Tell your healthcare provider if you experience any of the following:

  • Fever and/or chills
  • Increased pain, redness, swelling, or bleeding or other drainage from the insertion site
  • Coolness, numbness and/or tingling, or other changes in the affected extremity
  • Any changes in bodily functions or neurological changes, such as extreme headache, seizure, or loss of consciousness

Generally, a cerebral angiogram will be done periodically after the procedure make sure the coiling is working. The first angiogram may be done about one month after the procedure. Additional cerebral angiograms and/or other imaging procedures, such as MRI or MRA may be done at intervals to be determined by your healthcare provider based on your condition and the results of previous post-coiling imaging procedures.

Your healthcare provider may give you other specific instructions about what you should do after an endovascular coiling.

Next steps

Before you agree to the test or the procedure make sure you know:

  • The name of the test or procedure
  • The reason you are having the test or procedure
  • What results to expect and what they mean
  • The risks and benefits of the test or procedure
  • What the possible side effects or complications are
  • When and where you are to have the test or procedure
  • Who will do the test or procedure and what that person’s qualifications are
  • What would happen if you did not have the test or procedure
  • Any alternative tests or procedures to think about
  • When and how will you get the results
  • Who to call after the test or procedure if you have questions or problems
  • How much will you have to pay for the test or procedure