OHSU

Cerebral Aneurysms

An aneurysm is a small bubble that forms on the wall of an artery, a blood vessel that carries blood to the brain. The aneurysm has a thin wall, compared to the thicker wall of a normal brain artery. This thin walled bubble is prone to rupturing.

What causes brain aneurysms?

An aneurysm is the result of a weakness in the wall of a blood vessel. High blood pressure and smoking are some factors that may cause weakness in the wall of an artery, leading to aneurysms. Some brain aneurysms seem to occur in families, and there may be a genetic cause. Most aneurysms occur without any known cause. Other than controlling high blood pressure and stopping smoking, there is little a patient can do to help stop the growth and formation of aneurysms.

How long has my aneurysm been present?

Unless you have had imaging studies of your brain showing the growth of an aneurysm, we cannot tell how long an aneurysm has been present. It may have been there for years, or as short a several months. No one really knows.

What can go wrong with aneurysms?

We are mostly concerned about two things when you have an aneurysm, bleeding and enlargement. An aneurysm can break and cause bleeding in the brain. This bleeding is a type of stroke called “subarachnoid hemorrhage”, abbreviated “SAH”. An aneurysm can also enlarge and cause pressure on either the brain itself or nerves that arise from the brain, and typically go to muscles in the face, eye, or neck.

What is the chance my aneurysm will bleed if it has not bled in the past?

The exact risk of bleeding for your aneurysm cannot be known. Very small aneurysms (1-2 mm) seem to have very little risk of bleeding.  We generally advise patients that aneurysms of a certain size have a chance of bleeding that may be less than one percent up to several percent per year. This is the risk that the aneurysm will bleed between now and one year from now. If you follow that aneurysm over the course of several years, the chance of bleeding is higher because you are exposed to the risk for a longer time. As an example to explain this reasoning, consider that you have a chance of getting in a car wreck when driving ten miles. The chance of getting in a wreck is higher if you drive one hundred miles

What happens if my aneurysm bleeds, and how do I know it has happened?

When an aneurysm bleeds, it usually causes the sudden onset of the worst headache of your life. Typically the headache is different from any headache you have ever had, especially in terms of its severity. Often there is nausea and vomiting. If the bleeding is severe patients often lose consciousness. A bleeding aneurysm can cause serious problems. In about a third of the cases, successful treatment can lead to a complete recovery. In about a third of cases, the patient will survive but may go on to have a bad stroke. In the remaining third, the bleed is ultimately fatal.

What is the chance my aneurysm will continue to enlarge, and will that increase the risk of bleeding?

Sometimes we can do tests that show aneurysms grow, but often they remain about the same size, sometimes for years. We generally think that an aneurysm that grows is dangerous. Even aneurysms that do not grow still have a risk of bleeding. If an aneurysm is growing and causing effects, the aneurysm will generally continue to enlarge and cause more problems.

What happens if my aneurysm enlarges but does not bleed, and how do I know this has happened?

When an aneurysm enlarges, usually it occurs over a fairly long period of time, weeks or months, sometimes years. The signs and symptoms of an enlarging aneurysm may be slow to develop. If the nerves to your eye are affected, you may notice decreased vision in one eye, occasionally both. Double vision is fairly common. Some patients complain of headaches that are not their usual type. Often these headaches occur behind one of their eyes. Typically these headaches are not as severe as when an aneurysm bleeds, but still bad. Depending on the location of an aneurysm, weakness in the arms, legs, and hands or on one side of the body may occur.

Can all aneurysms be treated with coils, and how is that decided?

Most but not all aneurysms can be safely and effectively treated with coils. The decision about how to treat an aneurysm is made based on an angiogram. CT Angiography (CTA), Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiography (MRA) can give some idea about how to treat an aneurysm, but those tests are usually not reliable enough to make the final decision.

Why are stents used in the treatment of an aneurysm?

Some aneurysms have a wide neck that could result in the coil falling out of the aneurysm into the main artery, but can still be safely and effectively treated with coils.  In this case we can still treat your aneurysm by placing a stent in the artery.  The stent is a scaffold of metal that holds the coils in place inside the aneurysm.  The stent is approved for brain aneurysm treatment. Usually we start you on Plavix 75 mg and aspirin 325mg five days prior and also on the morning of your treatment. Alternatively we would give you Plavix 600 mg and aspirin 325 mg the day before your surgery. If a stent is used you need to be pretreated with aspirin and Plavix before the procedure and then after the procedure Plavix will be taken for 3 months and aspirin for 6 months.

How do your treat a brain aneurysm with coils?

The first step in treatment of aneurysms with coils is to do an angiogram. We have prepared another handout that describes a cerebral angiogram you should read this. When we treat an aneurysm with coils, we generally have the patient completely asleep and an anesthesiologist present to monitor the patient. Patients are placed under general anesthesia because it makes the procedure safe and more comfortable for the patient. After the patient is asleep, a small, thin, hollow, soft tube called a “catheter” is placed in the artery in the leg, and navigated over a wire gently through the arteries in the body to about the level of your chin, and the wire is pulled out, and the catheter left in place. This catheter is about 1/8 of an inch wide, but long enough to reach from the leg to the neck. Depending on where the aneurysm is located, the catheter is put in the carotid artery in the front of your neck, or the vertebral artery in the back of your neck. Placement of the tube is done by continuously watching the tube move through the body on an X-ray monitor. Once this catheter is placed, a much smaller catheter, called a “microcatheter”, is gently pushed over a smaller, very soft wire through the first larger catheter. The microcatheter is very thin, soft and also hollow. It is navigated through the arteries in the neck, and into the artery in the brain where the aneurysm is located. This movement is all done while continuously viewing the catheter movement on the X-ray monitor. The advanced angiography equipment we have at OHSU allows us to see the blood vessel, the aneurysm, and the microcatheter all together continuously from the front and the side. The microcatheter is then gently guided into the aneurysm itself, so that the tip is outside the normal artery, going through the neck of the aneurysm, and into the aneurysm itself. The wire over which the microcatheter is advanced is then removed, leaving the hollow microcatheter in place, with the tip in the aneurysm. After the microcatheter is in the aneurysm, soft metal coils made of platinum are gently pushed into the aneurysm. These coils wind and bend because they are very soft, and fill up the aneurysm. Several coils may be placed in the aneurysm to completely fill it. Once we have filled the aneurysm with coils, the microcatheter is removed from the aneurysm and pulled out of the body. The catheter in the neck is used to take more pictures, and then removed by pulling it out at the leg. After the catheter is removed from the leg, a suture is generally used to close the hole in the artery in the leg, where the catheter was introduced through the skin. This suture is under the skin and does not need to be removed.

How does the coil treat the aneurysm, and how quickly is it effective?

Once the coils are in the aneurysm and the microcatheter removed, blood begins to clot on the coils since the coils are a foreign body. Clotting happens very quickly, within hours, and provides protection against bleeding. Over the next six weeks, the clot changes into scar tissue that provides more protection from bleeding. The clot that forms is good in that it leads to the closure of the aneurysm, and eventually changes into firm scar. There is a risk that clots can form and fall out of the aneurysm into the normal artery, blocking flow. This is a risk and can cause a stroke. By keeping the coils well inside the aneurysm, often with a stent, this risk is low. Occasionally the scar forms but the aneurysm still enlarges at the neck. In this case additional treatment may be necessary in the future.

What should my family and friends do when I am undergoing treatment?

There is a waiting room on the 11th floor of OHSU hospital by the elevators called Family Waiting Room.  If the phone rings, they should answer it. Your family does not have to spend all their time in this waiting area, they are free to wander as they wish, however this is the only place we can give updates. These procedures typically take 2 to 4 hours, occasionally longer. When we have completed the treatment we will discuss the results with your family and friends if you want us to do so. At that time we try to return any films you have brought with you, and give you copy of your current treatment angiogram. We will send word out when we start the procedure, and give updates at least hourly.

What should I do the day before I have my aneurysm coiled and the day of the procedure?

The procedures are done with a general anesthetic, and you should have nothing by mouth from midnight onward the day of the procedure. If you do eat or drink the anesthesiologist will cancel your case for that day. You will be instructed about any medicines you normally take. If we discussed placing a stent in the artery to help treat your aneurysm, you should be taking aspirin and Plavix the day before your procedure, and also when you first wake up on the day of your procedure. We will try to give you a time that you will be at the hospital on the day of your treatment. If you are the first case you should come to the 9th floor admissions desk in OHSU Hospital at 06:30AM, and from there you will be directed two floors up to the 11th floor Interventional Recovery Unit (IRU).  Your family or friends can accompany you. If you are scheduled for a later start, you may be able to come in later. We rely on the anesthesiologist to give us the starting time, and we do not know that time until the afternoon prior to your procedure. You should bring any films you did not leave with us. Please leave a number we can contact you at the night before the procedure, especially if you are coming in from out of town. You can expect some delays, so bring a book, and be prepared to wait, although we will try to keep that wait to a minimum. Please call Barbara at 503-494-7736 at 3:00 pm the day before your procedure to find out what time to come into the hospital.

What should I bring with me?

You should bring an updated list of your medications and doses, and the names addresses, and phone numbers of your primary care physician and any doctors you want us to send a report to.

What happens right after the aneurysm is treated with coils?

The anesthesiologist will usually wake you up in the radiology department, although patients often have no memory of waking up until they go to their hospital room. You will be watched overnight in the intensive care unit (ICU). That night the nurses will check you on very frequently and you will not get much rest. We would like you to get out of bed that same day if your leg is stable from the arterial puncture. You may eat but for the first meal you will only have liquids, as some patients are nauseated. It is okay if you do not eat. If you are doing well you may go home the next day. If you have pain you will be given pain medicines, although pain is usually mild. Some headache pain is very common, as is soreness at the groin for several days. Your family and friends can visit you once you have awoken from the anesthesia and are in the ICU. Generally, most patients go home the day after the procedure around 10:00am

What about after I am discharged from the hospital?

You can expect to feel very tired for several days after the treatment, mostly as you recover from the general anesthetic. We encourage you to resume normal activities as soon as possible. Walking is a great exercise to regain strength. If your aneurysm had bled you may have some increased limitation on your activity, if it had not bled early activity is encouraged. We would like for you to return to our clinic the next week to answer any questions you have. If you live far away we can often do the follow-up by phone, although we prefer to see you back in clinic.

What are the risks of treating aneurysms using coils?

We are treating your aneurysm because we think the risks of the aneurysm untreated are higher than the risks of treatment. Still, there are risks of this therapy you need to be aware of and accept before having your aneurysm treated. The major concerns we have treating your aneurysm with coils are: causing bleeding from the aneurysm, blocking off normal blood vessels in the brain and causing a stroke, and incompletely treating your aneurysm. We do everything possible that we can to prevent these problems, but even in experienced hands these risks still are present. Aneurysms have thin walls compared to normal blood vessels and there is the chance it can rupture during treatment. We try to avoid this problem by being very careful with the catheters and coils, and the risk of bleeding is low. However, bleeding is a bad complication and can lead to loss of life or stroke. The aneurysm is not a normal artery and blocking it off is usually very safe. However, if a normal artery is blocked off during the course of treatment that can cause a stroke. Strokes can cause paralysis, blindness, loss of the ability to speak, and even loss of life. Normal arteries can be blocked off if a clot forms and plugs up a normal artery, or if a coil falls out of the aneurysm and blocks off a normal artery. The risk of this is also low. Coil treatment of aneurysms is done to prevent bleeding and growth of aneurysms. It appears to be very safe and effective, but in some instances the aneurysm can continue to grow. If this problem occurs the aneurysm may be retreated with coils, or we sometimes recommend surgery in this instance. Some embolization procedures can be lengthy, and the x-rays can cause temporary hair loss. If you experience this hair loss, be assured that it will grow back.  The typical places for this hair loss are on the back of the head or above the right ear.

There are also the risks of the angiogram, which in our hands is a very safe procedure. The other handout describing angiography goes into more detail on the risks of this procedure.

With these kinds of risks, why should I have my aneurysm treated?

An untreated aneurysm has the risks of bleeding into your brain.  Or enlargement. We think the risk of having an untreated aneurysm is greater than the risk of treatment.

What sort of followup do I need for my aneurysm after it is treated with coils?

After your procedure we will send a letter and reports of your treatment to your primary care physician and referring doctors. We encourage you to follow-up with them. We will give you selected pictures from your treatment, and would like for you to show them to your doctors. You may keep these or give them to your doctor. We generally recommend that you have a follow-up angiogram 3-6 months after treatment of your aneurysm, to insure it is not continuing to grow. This recommendation is often altered depending on your age, medical history, or individual circumstances. Another study would be done 6 months to one year later.

If the neuroform stent has been placed, you should take aspirin (325 mg, one adult tablet) for 6 months, and Plavix (75 mg) for 3 months.

Can aneurysms grow back after treatment?

Yes, and that is why it is important for you to have follow-up as listed above. Fortunately regrowth of aneurysms can be treated with additional coils, usually in a straightforward fashion. It is unlikely your aneurysm will ever need additional treatment.

How long have aneurysms been treated with coils, and how much experience do you have doing this treatment?

The treatment of aneurysms using coils was first described around 1990. Before that time small balloons were placed in aneurysms and then inflated, leading to closure of the aneurysm. This technology was very commonly used in the Soviet Union, where surgery for aneurysms was not particularly successful. The currently available coils have replaced that technology. The Neurointerventional Service at Oregon Health & Science University, under the directions of Drs. Stanley Barnwell, Gary Nesbit, Bryan Petersen, Aclan Dogan, and David Lee, was one of ten centers in the U.S. involved in the initial trial determining the safety and effectiveness of treating aneurysms with coils. This trial began at OHSU in 1992 and approval by the FDA for this therapy was given in September 1995. At OHSU, as of November 2004, we have performed over 1500 embolizations of aneurysms using coils. Experience with this technique is the most critical factor leading to a successful treatment.

What are coils and stents made from and what does that mean?

The coils we use for aneurysms are made from platinum. Platinum never breaks down in the body and will remain forever.  It is safe to have MRI’s if the coils are used, as they do not affect that test. You can also have CT scans, but the coils will cause artifacts on a brain scan. There have been no untoward reactions to platinum coils; they do not cause allergic reactions. The Neuroform stent is made of a metal that is similar to platinum in its stability and MRI compatibility.

Do I have other options for treatment of my aneurysm other than coils?

Currently aneurysms are treated by either surgery, which involves a brain operation to place a clip on the aneurysm from outside the blood vessel, or by coiling. Some aneurysms are better managed by surgery, others by coiling. Some aneurysms are difficult to treat by either method and in that case no treatment, other than observation, may be the best option. We will discuss these options with you, and the ultimate decision on how to treat an aneurysm lies with the patient and/or their family.

What if I have more than one aneurysm?

About 10% of patients have more than one aneurysm. These other aneurysms can sometimes be treated with coils, surgery, or sometimes we just recommend following these other aneurysms by MRI or MRA, especially if they are small.

If you cannot treat my aneurysm with coils, then what?

Depending on a variety of circumstances, your aneurysm may be suitable for treatment with surgery, or in some instances we may recommend no treatment. Lasers and radiation have no role in the treatment of brain aneurysms.

Is there research ongoing on new treatments for aneurysms?

Yes, there are many medical device companies working on new therapies for aneurysms. Some of these therapies utilize stents, glues, and new types of coils. The Neurointerventional service is actively involved in research activities in aneurysm and stroke therapy.

How do I contact you after the procedure?

During the day we can be reached at 503-494-7736.
If it is after hours please call the paging operator at 503-494-9000 and ask for the Neurointerventional services or the Neurosurgeon on call to be paged.
If it is an emergency go to the nearest emergency room.