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Table of Contents    
Year : 2015  |  Volume : 63  |  Issue : 6  |  Page : 826-828

Unruptured intracranial aneurysms

Department of Neurosurgery, Institute of Neurosciences, Kolkata, West Bengal, India

Date of Web Publication20-Nov-2015

Correspondence Address:
Robin Sengupta
Department of Neurosurgery, Institute of Neurosciences, Kolkata, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0028-3886.170064

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How to cite this article:
Sengupta R. Unruptured intracranial aneurysms. Neurol India 2015;63:826-8

How to cite this URL:
Sengupta R. Unruptured intracranial aneurysms. Neurol India [serial online] 2015 [cited 2022 Aug 19];63:826-8. Available from: https://www.neurologyindia.com/text.asp?2015/63/6/826/170064

A 56-year-old woman came to my clinic for an opinion in January 2013 for an unruptured aneurysm detected while she was being investigated for a nonspecific headache. The computed tomographic (CT) angiogram demonstrated a 9-mm diameter posterior communicating artery aneurysm on one side, and another 3-mm diameter carotid-ophthalmic aneurysm on the opposite side. The posterior communicating artery aneurysm had a good neck suitable for both clipping as well as coiling. My advice was to treat the posterior communicating artery aneurysm. Her family was not convinced. However, after some months, she consulted an endovascular neuroradiologist who arranged for coiling.

Two days before the date of coiling, she suffered a massive subarachnoid hemorrhage and was admitted to a local hospital. Her CT scan showed subarachnoid hemorrhage with dilated ventricles. Her condition remained critical, and no specific treatment was given. Twenty-four hours after the ictus, she was transferred under my care.

At admission, she had Hunt and Hess grade V subarachnoid hemorrhage. An emergency ventricular drainage was instituted, and the aneurysm was coiled. She recovered after a prolonged hospital stay, with hemiparesis and some cognitive impairment.

The fear of further hemorrhage from the much smaller carotid-ophthalmic aneurysm prompted its coiling too. This case history provides a number of lessons in the management of unruptured intracranial aneurysms (UIAs).

UIA is a source of great confusion among the caregivers as well as anxiety for the patient, a target for unnecessary treatment, and as yet, an unsolved problem as far as their appropriate management is concerned. Once detected, the physicians in general are unsure of giving correct advise to the patient about its significance, and even less so, about its management. If a person comes to know that he/she is having an aneurysm in the brain, which may be described as a 'bomb that can burst', serious anxiety accompanies the diagnosis until it is treated. However, the treatment may be unnecessary, harmful, or beyond the patient's means.

The surveillence for UIAs is a recent phenomenon. In 9% of the brain, one or more unruptured aneurysm had been found when looked for, on routine postmortem examination in the elderly.[1],[2]

However, with the large-scale use of imaging methods, more and more UIAs are now being detected. It is now accepted that just more than 3% of the population harbors an UIA in their brain. Nevertheless, the incidence of subarachnoid hemorrhage from an unruptured aneurysm is only 0.25%, and the incidence of UIAs causing pressure effects on neighborhood structures in the population is extremely small.[3] Therefore, a large number of UIAs will remain totally harmless and neither need to be treated nor should be a cause for anxiety.

Once detected, however, there are two questions in the mind of the patient and the caregivers for which there should be a clear answer. First, should a particular UIA be treated? Second, if treatment is required, what is the best mode of treatment among the three management modalities: Observation, surgical clipping, or endovascular treatment?

The factors increasing the propensity of UIAs to rupture have not yet been resolved. However, from the available knowledge, an increased risk of rupture may be ascertained from the following factors:[4],[5],[6]

  • Size of the aneurysm being 7 mm or more in diameter [7]
  • Location of the aneurysm being in the anterior communicating artery region. The author contends that most of the aneurysms found ruptured in this location are less than 7 mm in diameter, and hence, this location may have some clinical significance
  • Previous history of subarachnoid hemorrhage
  • Documented increase in the size of aneurysm during follow-up.

The treatment chosen for a particular UIA must be rational, effective, and with acceptable risk. Observation alone after an informed consent may be recommended if that is the patient's preference. Observation only will be a rational decision if the aneurysm is smaller than 7 mm in diameter, the patient is elderly, if there are associated illnesses that considerably increase the risk of surgery, or the patient is not prepared to accept any risk. For a preferred choice of surgical clipping, the following factors should be stressed:

  • It is effective with Class I evidence
  • Risk of surgery is acceptable and is much lesser in the hands of a high-volume operator but is much more in uncommon locations such as the posterior circulation
  • It is more invasive, as vessels in the brain need to be exposed
  • It is less expensive.

In a meta-analysis, Ruan et al.,[8] have shown that clipping has 1% mortality with a 95% obliteration rate in aneurysms that are surgically accessible. However, a single-center experience by Song et al.,[9] demonstrated extremely good results, with the morbidity being 0.25% and the mortality being 0.3%.

In the case of endovascular therapy, the factors of importance are as follows:

  • It can be recommended as effective with Class II evidence
  • The procedural risk is acceptable and is less for a high volume operator
  • It is less invasive and hence more user friendly
  • It is more expensive.

In a meta-analysis, Ruan et al.,[8] demonstrated that the endovascular treatment was associated with a 2% mortality and only 82% obliteration rate, whereas in a retrospective study, Song et al.,[9] have shown a morbidity of 0.8% with a mortality of 0%.

In the long-term follow-up of patients in the International Subarachnoid Aneurysm Trial (ISAT),[3] the endovascular group faired better at 10 years than the neurosurgery group. As the case selection was very specific, the results cannot be accepted as significant.

The information regarding UIAs and their management should be available to the patient. This should be followed by a joint consultation between the neurosurgeon and the endovascular surgeon, along with the family physician, if available (the presence of the family physician is needed to avoid a biased view from any quarter). In a country like India, the cost of therapy for conditions with an uncertain course, such as an UIA, should be taken into account. Finally, any caregiver wishing to be updated regarding the present state of knowledge related to UIAs must read the review by Ambekar and Pandey published in the current issue of Neurology India.[10]

In the case history that I started with, the patient had an unruptured aneurysm of significant size. The family, however, did not accept the advice to undergo intervention for several months. There was no urgency on the part of the endovascular specialist to coil the aneurysm, which resulted in its rupture. After all her suffering from massive hemorrhage, the family insisted on coiling the carotid-ophthalmic aneurysm of insignificant size owing to the unnecessary fear of bleeding from it. The author contends that if the natural history of UIAs according to their location is studied, a small aneurysm in the carotid-ophthalmic area or the middle cerebral bifurcation in the elderly comprises the largest number of unruptured aneurysms found.

The author finds the recommendation of American Stroke Association [11] invaluable but contends that the jury has still not come to a consensus regarding the final management protocol for UIAs.

  References Top

Menghini VV, Brown RD Jr, Sicks JD, O'Fallon WM, Wiebers DO. Incidence and prevalence of intracranial aneurysm and hemorrhage in Olmsted County, Minnesota, 1965 to 1995. Neurology 1998;51:405-11.  Back to cited text no. 1
Sengupta RP, Mc Allister VL. Subarachnoid Hemorrhage. Berlin: Springer-Verleg; 1986. p. 41.  Back to cited text no. 2
Molyneux AJ, Birks J, Clarke A, Sneade M, Kerr RS. The durability of endovascular coiling versus neurosurgical clipping of ruptured cerebral aneurysms: 18-year follow-up of the UK cohort of the International Subarachnoid Aneurysm Trial (ISAT). Lancet 2015;385:691-7.  Back to cited text no. 3
Backes D, Vergouwen MD, Tiel Groenestege AT, Bor AS, Velthuis BK, Greving JP, et al. PHASES score for prediction of intracranial aneurysm growth. Stroke 2015;46:1221-6.  Back to cited text no. 4
Greving JP, Wermer MJ, Brown RD Jr, Morita A, Juvela S, Yonekura M, et al. Development of the PHASES score for prediction of risk of rupture of intracranial aneurysms: A pooled analysis of six prospective cohort studies. Lancet Neurol 2014;13:59-66.  Back to cited text no. 5
Juvela S, Poussa K, Lehto H, Porras M. Natural history of unruptured intracranial aneurysms: A long-term follow-up study. Stroke 2013;44:2414-21.  Back to cited text no. 6
Unruptured intracranial aneurysms—Risk of rupture and risks of surgical intervention. International Study of Unruptured Intracranial Aneurysms Investigators: N Engl J Med 1998;339:1725-33.  Back to cited text no. 7
Ruan C, Long H, Sun H, He M, Yang K, Zhang H, et al. Endovascular coiling vs. surgical clipping for unruptured intracranial aneurysm: A meta-analysis. Br J Neurosurg 2015;29:485-92.  Back to cited text no. 8
Song J, Kim BS, Shin YS. Treatment outcomes of unruptured intracranial aneurysm; experience of 1231 consecutive aneurysms. Acta Neurochir (Wien) 2015;157:1303-11.  Back to cited text no. 9
Ambekar S, Pandey P. Treatment of unruptured intracranial aneurysms—Current perspective. Neurol India 2015;63:853-60.  Back to cited text no. 10
Thompson BG, Brown RD Jr, Amin-Hanjani S, Broderick JP, Cockroft KM, Connolly ES Jr, et al. Guidelines for the management of patients with unruptured intracranial aneurysms: A guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2015;46:2368-400.  Back to cited text no. 11


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