The definition of 'elderly' may vary according to chronological, biological, psychological, and social aspects, however, most developed countries have accepted the chronological age of 65 years as a definition of 'elderly' or older person, as defined by the World Health Organization (WHO). Advances in medical science have led to an increase in life expectancy, and, consequently, the proportion of elderly people among the total population. In 2013, approximately 12.2% of the Korean population was aged over 65 years.11) With continued expansion of the aging population, and the development of less invasive and high-quality neuroimaging modalities, more elderly patients are expected to develop intracranial aneurysms.

As supportive intensive critical care and neurointerventional treatment options become more advanced, more aggressive treatment of elderly aneurysm patients is being encouraged.1) Aggressive treatment for many conditions is becoming more common, resulting in more positive outcomes.5)16)20) The aim of our study was to describe intracranial aneurysm treatments in all elderly patients treated in our institute and to observe their clinical course and immediate prognosis under aggressive therapy.

This is a retrospective, cross-sectional study from a single institution. The medical records of all patients treated at our hospital from September 2008 to December 2013 were reviewed for selection of patients aged 65 years or older who underwent microsurgical clipping or endovascular management for treatment of an intracranial aneurysm. To reduce variability, a single vascular neurosurgeon performed all microsurgical clippings and endovascular coilings in these patients. Clinical information obtained included age, sex, Hunt and Hess grade (HHG), aneurysm location, Fisher grade (FG), and treatment (microsurgical clipping, endovascular coiling). To determine which risk factors affected the functional outcome, clinical data including hypertension, diabetes, and previous medication were evaluated as well.

All eligible patients were placed in the microsurgical clipping group or the endovascular coiling group. The HHG were evaluated at admission. Clinical outcome at the time of discharge was assessed for each patient using the Glasgow outcome scale (GOS) score: favorable outcome (good recovery, GOS 5; moderate disability, GOS 4) or poor outcome (severe disability, GOS 2-3; death, GOS 1).

Statistical analysis was performed using commercially available software (SPSS version 18, SPSS Inc., Chicago, IL, United States). Univariate comparison of continuous variables with a normal distribution was performed using two sample t-tests. All categorical data were assessed by χ² test or Fisher's exact test. Logistic regression was used to test bivariate associations between variables of interest and good versus poor outcome. A p value < 0.05 was considered statistically significant.

In this study, the primary finding was that patients with high grade HHG, increasing age, and intraventricular hematoma (IVH, FG4) had poor clinical outcomes as compared to patients without these factors, which were as follows. The initial clinical presentation of patients is the highest predictive power of the outcome. In our series, the final mortality rate and percentage of severely disabled patients with high grade HHG (HHG IV, V) was 28.3% and 24.5%, respectively. A favorable outcome was achieved in 31% of treated patients, higher than the result from previously published studies.5)7) In patients with a poor clinical grade with acute hydrocephalus and significant IVH (FG4), early placement of an external ventricular drainage (EVD) prior to aneurysm securing intervention improved the level of consciousness and short-term outcome.15)17)19) This study also demonstrated that placement of an EVD improved the clinical grade and outcome.

The secondary finding is that both microsurgical clipping and coiling yielded excellent results in elderly patients with unruptured aneurysm. The overall morbidity and mortality rates were 2% and 0% in each respective treatment modality, similar to those found in the literature.3)8)12)14) Currently, there are no established guidelines for ideal management of UIAs in elderly patients. In the distribution of aneurysm sizes, larger sized unruptured aneurysms were more common in the older age group and the annual incidence of SAH was noted to be three times higher.2)6)21) Thus, some researchers have suggested that elderly patients with UIAs should be considered for active surgical intervention to improve their outcomes. Advanced age alone has been reported to increase the risk of complications in elderly patients with unruptured aneurysm undergoing microsurgical clipping or endovascular coiling.4)10) In the current study, more patients with UIAs were treated by endovascular coiling (76.5%) and the mean age was significantly older than that of the microsurgical clipping group. To our surprise, favorable results have been obtained from both treatments along with our results. Our study supports the idea that surgical treatment of UIAs in the elderly should be advocated in making decisions on the optimal treatment strategy after careful assessment of each individual's circumstances.

In the ruptured aneurysm group, nine (47.4%) patients died from 'other' causes unrelated to SAH. Among the eight patients who died, five died of pneumonia and three died of sepsis and/or multiorgan failure. According to these results, more than one-third of the patients died within the acute period of the SAH, even if it was not due to the hemorrhage. Clinical care of elderly patients is challenging because of a greater chance of pharmacological complications, cardiopulmonary dysfunction, and so on. Elderly patients who survive SAH often face prolonged management in an intensive care unit (ICU), including treatment for multiple potential neurological and medical complications.13)18) Therefore, for proper co-management of these patients, in order to handle multiple issues, it is necessary to employ a more specialized neurointensivist dedicated to the ICU.9)

This study is limited by the fact that it was a retrospective review, with a limited number of patients at a single institution and no strictly defined selection criteria for the treatment procedure along with a lack of long-term follow up results. Lack of standard treatment guidelines and sufficient prognostic domestic data concerning treatment of aneurysms in the elderly make it difficult for clinicians when it comes to deciding on the proper treatment modality in such patients. We believe that our study may provide a valuable guide to help in decision making regarding treatment enrollment of elderly patients who could benefit from treatment, despite the known challenges in the management of this age group.

According to our data, elderly patients with high grade HHG and IVH are truly associated with poor outcome, so that the indication for aggressive therapy should be considered carefully. To improve outcomes in elderly SAH patients, co-management by specialized neurointensivists who can handle patients with multiple conditions should be considered. According to our data, all elderly patients with UIAs had an excellent outcome, regardless of the treatment modality. Treatment of unruptured intracranial aneurysms can be considered in an optimistic way.