Asymptomatic Right MCA Aneurysm

Contributor:

Dr. Chris Ekong

Consultants:

Dr. Mike Tymianski
Dr. Michael Schwartz
Dr. R Willinsky
Dr. J Max Findlay

Case 4

Age: 43

Sex: Female

History: She presented to an ENT surgeon in April 2000 with symptoms of sinusitis. CT of the head was done and showed a globular right sylvian mass. This was suspected to be an aneurysm. An angiogram was therefore organised.

Comments:

To Neurorovascular Internet Rounds Group - September 23, 2000

Gentlemen:

Please find enclosed, CT and angio on a 43 year old lady with asymptomatic 8mm right MCA aneurysm. Would you clip it, coil it, or leave it alone?

Your brief commens would be appreciated.

NB: As usual, your comments will be posted for teaching purposes.

Yours sincerely,

Chris

Dr. Max Findley, Neurosurgeon, Edmonton - October 2, 2000

Chris:

I would recommend surgical repair of this aneurysm. At age 43, with at least 35 more years to live, and with an aneurysm that is 8 mm in size, I think that her life time risk of bleeding from this aneurysm (which can be estimated to be between .5 and 1% per year and even higher if she is a smoker) is at least 20%. That is using the equation of cummulative probability and I am taking into consideration not only the ISUIA, but also the recent paper from Finland in the Journal of Neurosurgery, September issue, with Juvela as the first author

Our experience, and I believe the experience of many others, is that middle cerebral artery aneurysms are suboptimal for endovascular repair, often, owing to the broad bifurcation of the M1 segment which becomes "taken up" into the dome of he aneurysm. Yours truly,

Max

Dr. Cameron MacDougall, Neurosurgeon, Phoenix, - October 2, 2000

Chris:

Middle cerebral bifurcation aneurysms tend to be a little tricky for endovascular coiling because it is often difficult to define the neck relative to the parent vessel. The image provided for this case suggest that this aneurysm is relatively broad necked and may actually incorporate the parent vessels. Even if this were not the case I believe that for this individual the appropriate options are surgical clipping or no treatment. The natural history debate continues to rage and the issue with respect to this patient is really a matter of what one belives is the natural history of this aneurysm. If one believes Wiebers data is the most accurate reflection of the natural history then probably no treatment is indicated. By comparison if one feels that the data of Juvela et al (J Neurosurg 93: 379-387, 2000) is more consistent with clinical observations then I believe that this woman would undergo surgical clipping of the aneurysm. I think that the natural history is likely to be worse than what Wiebers has suggested and would recommend surgical clipping. Best,

Cameron MacDougall

Robert Willinsky, Neuroradiologist, Toronto - October 2, 2000

Dear Chris:

My inclination is that the patient be treated. I would not recommend endovasuclar treatment since the aneurysm appears to have a wide neck and the morphology is not suitable for a remodelling technique. In addition, the thrombolic complications related to GDC treatment are higher in this location compared to other locations. Is the patient a smoker? If she is she should be encouraged to stop smoking. Thanks for asking me to comment on this case. Best Regards,

Bob

Dr. Mike Tymianski, Neurosurgeon, Toronto - October 2, 2000

Chris:

1. To treat or not to treat?

Difficult question in the light of the range of published studies. Each has been quoted for-or-against treatment, depending on "mood". In th end, I have chosen to explain to the patient the range of studies out there, and to indicate that according to the present liturature, the risk of hemorrhage from an asymptomatic aneurysm > 6mm but < 10mm is somewhere in the range of 0.05 to 2.3% a year. Unfortunately, I do not have the ability, based on current literature to narrow things down any further. Thus, the patients must make up their minds about whether or not they are willing to live with this risk range.

2. If to treat:

In a young patient such as this, I would be biasd towards offering a definitive treatment. Until endovascular therapy is shown to last, I would offer surgery for an aneurysm like this one. I believe that the risks of surgery for this aneurysm are at least as low as those of endovascular. I would also explain the availability of endovascular treatmet, and explain that this may also be an option, depending on the technical feasibility of coiling. If it is an option, I would advise the patient that he/she will need a follow up angiogram at 6 months and at 3 years of the initail result is perfect. If it is not perfect, the frequency of folow up angiography may need to be adjusted. For this particular aneurysm, it appears that the neck is broad, and arises from trifurcation. If coiling is to be considered, I would ask the patient to undergo 3-D angiography to better define the toporgraphy of the aneurysm neck. We have found this to be an increasingly useful tool in our diagnostic and therapeutic plans. I think that the opinion about feasibility of (perfect) coiling may vary among neuroradiologists.

Please let us know what you did. Best,

Mike T

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