364
Surg Neurol 1992;38:364-70
U nruptured Intracranial Aneurysms in Elderly Patients Tetsuji Inagawa, M.D., Hiroshi Hada, M.D., and Yukio Katoh, M.D. Department of Neurosurgery, Shimane Prefectural Central Hospital, Izumo, Japan
Inagawa T, Hada H, Katoh Y. Unruptured intracranial aneurysms in elderly patients. Surg Neurol 1992;38:364-70.
A total of 556 patients with 769 intracranial aneurysms, of which 256 were unruptured and 513 were ruptured, were included in the present study. The patients were divided into three age groups: those aged 59 years or younger, those aged 60 to 69 years, and those aged 70 years or older. Small aneurysms of 4 m m or less in diameter were more common in the series of unruptured aneurysms than in the ruptured aneurysms. The rupture rate in anterior communicating artery aneurysms was the highest, and it increased with age. A follow-up study was performed on 47 patients with 55 unruptured aneurysms, and only one giant basilar artery aneurysm ruptured during the average follow-up period of 5.2 years. Direct operation was performed on 52 patients with unruptured aneurysms. While the surgical mortality rate was 0%, the morbidity rate was 6% (three of 52 cases), which was not directly related to the patients' age. When considering surgery for unruptured aneurysms, rupture rate of aneurysms at each site is one of the most important factors, especially in elderly patients. KEYWORDS: Cerebral aneurysm; Unrupturecl aneurysm; Rupture rate; Natural history; Surgical outcome; Geriatrics
T h e diagnosis and treatment o f unruptured intracranial aneurysms are of great importance because the overall o u t c o m e of ruptured intracranial aneurysms still remains unsatisfactory [7,19,20,27]. Although autopsy studies have shown that the incidence o f unruptured incidental aneurysms is higher in older patients than in younger patients [16,29], the actual age-specific incidence of aneurysmal subarachnoid h e m o r r h a g e increases with age [18,21,26,36,38]. With an increasing older population, it is likely that neurosurgeons will see a great n u m b e r o f elderly patients with unruptured intracranial aneurysms. Although the operation for unruptured intracranial aneurysms carries a low risk o f morbidity and mortality
Address reprint requests to: Tetsuji Inagawa, M.D., Department of Neurosurgery, Shimane Prefectural Central Hospital, 116 Imaichicho, Izumo, Shimane 693, Japan. Received March 30, 1992; accepted July 8, 1992.
© 1992 by ElsevierSciencePublishingCo., Inc.
[7,11,15,22,31,33,37,39,40,46], and the surgical results for elderly patients with ruptured aneurysms have been improved [1,7,14,19,20], whether or not to operate on unruptured aneurysms discovered in old patients needs to be established. This study was conducted to examine our experience with unruptured intracranial aneurysms in elderly patients and assess the o u t c o m e o f surgical and expectant m a n a g e m e n t of such aneurysms.
Clinical Material
and Methods
During the 11-year period from 1980 to 1990, 556 patients with confirmed diagnosis o f 769 intracranial aneurysms were admitted to the D e p a r t m e n t o f N e u r o s u r gery o f Shimane Prefectural Central Hospital. O f the 769 aneurysms, 256 were unruptured: 202 were discovered in 145 patients with associated ruptured aneurysms, and 54 were discovered in 43 patients with no associated ruptured aneurysms. O f the 256 unruptured aneurysms, 250 were discovered incidentally, and six were symptomatic and of giant size. In this study, the patients were classified by age into three groups: 59 years or younger, 60 to 69 years, and 70 years or older. For these groups, a study was made o f (1) size and site o f aneurysms, (2) rupture rate of unruptured aneurysms, (3) follow-up study o f untreated unruptured aneurysms, and (4) surgical outcome for unruptured aneurysms. T h e rate o f rupture o f aneurysms at different sites was calculated by dividing the n u m b e r o f ruptured aneurysms at each location by the total n u m b e r o f a n e u r y s m s (both unruptured and ruptured) occurring at that location. The subjects o f our follow-up study were 47 patients with 55 unruptured aneurysms who were expectantly managed with no surgical treatment. T h e remaining 141 patients with unruptured aneurysms were either operated on (n -- 90), died soon after diagnosis (n -- 46), or excluded by other reasons (n = 5). T h e mean age o f this study g r o u p was 64 years (range 3 4 - 8 4 years). Eighteen patients with 20 unruptured aneurysms were no m o r e than 59 years old (mean 52 years), 11 patients with 11 aneurysms were 60 to 69 years old (mean 66 years), and 18 patients with 24 aneurysms were 70 years old or older 0090-3019/92/$5.00
Unruptured Intracranial Aneurysms in the Elderly
Surg Neurol 1992;38:364-70
365
Table 1. Size of Aneurysmsa Type of aneurysm
~4
5-9
10-14
15-19
20-24
->_25
Total
Unruptured Ruptured Total
139 (55) b 129 (25) ~ 268 (35)
87 (34) 264 (52) 351 (46)
18 (7) 81 (16) 99 (13)
3 (1) 13 (3) 16 (2)
0 (0) 3 (1) 3 (0.4)
6 (2) 19 (4) 25 (3)
253 (100) 509 (100) 762 (100)
Size of aneurysms is expressed in millimeters; number (%). The sizes of three unruptured and four ruptured aneurysms were not recorded. b Significance of difference, p < 0.01.
(mean 75 years). O f the 55 unruptured aneurysms, 34 were discovered in 29 patients with ruptured aneurysms that already had been clipped, and 21 were found in 18 patients with no associated ruptured aneurysms. The patients were followed up by personal consultations, telephone interviews, and letters. Information about possible new episodes o f subarachnoid hemorrhage and neurological symptoms were obtained from the patients or their close relatives. The follow-up period varied from 0.5 to 10.9 years, with an average of 5.1 years. The average follow-up period for patients aged 59 years or less, 60 to 69 years and 70 years or more were 5.2 years, 6.3 years, and 4.5 years, respectively. Direct operations for unruptured aneurysms were performed on 52 patients. Thirty-eight patients were 59 years old or younger, eight were 60 to 69, and six were 70 years old or older. O f the 52 patients, 30 had associated ruptured aneurysms that had been already clipped at least 1 month before the second surgery, and 22 had unruptured aneurysms alone. T h e surgical outcome 6 months after operation was assessed according to the Glasgow Outcome Scale [24]. Statistical analyses were done using the X 2 test. Results
Size and Site of Aneurysms Small aneurysms of 4 mm or less in diameter were significantly more c o m m o n in the unruptured aneurysm series than in the ruptured aneurysm series (Table 1). However, there was no significant difference among the
three age groups in the size of unruptured or ruptured aneurysms. Anterior communicating artery aneurysms were more common in the ruptured aneurysm series than in the unruptured aneurysm series (Table 2). Moreover, the incidence of unruptured anterior communicating artery aneurysms decreased with increasing age (Table 3). However, there was no significant difference in the site of unruptured aneurysms between the patients who had both ruptured and unruptured aneurysms and those who had unruptured aneurysms alone (Table 4). Table 5 shows the relationship between the site and size o f aneurysms. In the unruptured aneurysm series, the percentage o f small aneurysms o f 4 mm or less in diameter was the lowest in the middle cerebral artery; and in the ruptured aneurysm series, such small aneurysms were significantly more c o m m o n in the anterior communicating or distal anterior cerebral artery than in either the internal carotid or middle cerebral artery.
Rupture Rate of Unruptured Aneurysms In all of the three age groups, the highest rupture rate was observed in the anterior communicating artery aneurysms (Table 6). Furthermore, the rate of rupture o f the anterior communicating artery aneurysms increased with advancing age. Such a tendency was not observed in aneurysms at other sites.
Follow-up Study of Unruptured Aneurysms The sizes and sites o f the 55 unruptured aneurysms that were followed up are shown in Tables 7 and 8. The
Table 2. Site of Aneurysmsa Type of aneurysm
AComA
Distal ACA
ICA
MCA
VBA
Total
Unruptured Ruptured Total
24 (10) b 185 (37) b 209 (28)
28 (11) 30 (6) 58 (8)
96 (38) 134 (26) 230 (30)
83 (33) 133 (26) 216 (28)
21 (8) 24 (5) 45 (6)
252 (100) 506 (100) 758 (100)
Abbreviations: AComA, anterior communicating artery; ACA, anterior cerebral artery; ICA, internal carotid artery; MCA, middle cerebral artery; VBA, vertebrobasilar artery. Number (%). The sites of four unruptured and seven ruptured aneurysms were not recorded. b Significance of difference, p < 0.01.
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I n a g a w a e t al
T a b l e 3. Site of Unruptured Aneurysms in Three Age Groups ~ Age (yr)
AComA
Distal ACA
ICA
MCA
VBA
Total
-70
17 (13) b 6 (10) 1 (2) ~
16 (12) 5 (8) 7 (12)
49 (36) 18 (31) 29 (50)
43 (32) 23 (39) 17 (29)
10 (7) 7 (12) 4 (7)
135 (100) 59 (100) 58 (100)
Abbreviations: AComA, anterior communicating artery; ACA, anterior cerebral artery; ICA, internal carotid artery; MCA, middle cerebral artery; VBA, vertebrobasilar artery. Number (%). The sites of four aneurysms were not recorded. b Significance of difference, p < 0.05.
T a b l e 4. Site of Unruptured Aneurysms in Patients with Both Unruptured and Ruptured Aneurysms and with
Unruptured Aneurysms Alone a Patient classification
AComA
Distal ACA
ICA
MCA
VBA
Total
A B
17 (9) 7 (13)
24 (12) 4 (8)
70 (35) 26 (49)
70 (35) 13 (25)
18 (9) 3 (6)
199 (100) 53 (100)
Abbreviations: AComA, anterior communicating artery; ACA, anterior cerebral artery; ICA, internal carotid artery; MCA, middle cerebral artery; VBA, vertebrobasilar artery; A, patients with both unruptured and ruptured aneurysms; B, patients with unruptured aneurysms alone. ° Number (%). The sites of four unruptured aneurysms were not recorded.
T a b l e 5. Site and Size of Aneurysms a Ruptured aneurysms
Unruptured aneurysms Site of aneurysms AComA Distal ACA ICA MCA VBA
--10
3 1 12 9 2
(13) (4) (13) (11) (10)
-
Surg Neurol 1992;38:364-70
U nruptured Intracranial Aneurysms in Elderly Patients Tetsuji Inagawa, M.D., Hiroshi Hada, M.D., and Yukio Katoh, M.D. Department of Neurosurgery, Shimane Prefectural Central Hospital, Izumo, Japan
Inagawa T, Hada H, Katoh Y. Unruptured intracranial aneurysms in elderly patients. Surg Neurol 1992;38:364-70.
A total of 556 patients with 769 intracranial aneurysms, of which 256 were unruptured and 513 were ruptured, were included in the present study. The patients were divided into three age groups: those aged 59 years or younger, those aged 60 to 69 years, and those aged 70 years or older. Small aneurysms of 4 m m or less in diameter were more common in the series of unruptured aneurysms than in the ruptured aneurysms. The rupture rate in anterior communicating artery aneurysms was the highest, and it increased with age. A follow-up study was performed on 47 patients with 55 unruptured aneurysms, and only one giant basilar artery aneurysm ruptured during the average follow-up period of 5.2 years. Direct operation was performed on 52 patients with unruptured aneurysms. While the surgical mortality rate was 0%, the morbidity rate was 6% (three of 52 cases), which was not directly related to the patients' age. When considering surgery for unruptured aneurysms, rupture rate of aneurysms at each site is one of the most important factors, especially in elderly patients. KEYWORDS: Cerebral aneurysm; Unrupturecl aneurysm; Rupture rate; Natural history; Surgical outcome; Geriatrics
T h e diagnosis and treatment o f unruptured intracranial aneurysms are of great importance because the overall o u t c o m e of ruptured intracranial aneurysms still remains unsatisfactory [7,19,20,27]. Although autopsy studies have shown that the incidence o f unruptured incidental aneurysms is higher in older patients than in younger patients [16,29], the actual age-specific incidence of aneurysmal subarachnoid h e m o r r h a g e increases with age [18,21,26,36,38]. With an increasing older population, it is likely that neurosurgeons will see a great n u m b e r o f elderly patients with unruptured intracranial aneurysms. Although the operation for unruptured intracranial aneurysms carries a low risk o f morbidity and mortality
Address reprint requests to: Tetsuji Inagawa, M.D., Department of Neurosurgery, Shimane Prefectural Central Hospital, 116 Imaichicho, Izumo, Shimane 693, Japan. Received March 30, 1992; accepted July 8, 1992.
© 1992 by ElsevierSciencePublishingCo., Inc.
[7,11,15,22,31,33,37,39,40,46], and the surgical results for elderly patients with ruptured aneurysms have been improved [1,7,14,19,20], whether or not to operate on unruptured aneurysms discovered in old patients needs to be established. This study was conducted to examine our experience with unruptured intracranial aneurysms in elderly patients and assess the o u t c o m e o f surgical and expectant m a n a g e m e n t of such aneurysms.
Clinical Material
and Methods
During the 11-year period from 1980 to 1990, 556 patients with confirmed diagnosis o f 769 intracranial aneurysms were admitted to the D e p a r t m e n t o f N e u r o s u r gery o f Shimane Prefectural Central Hospital. O f the 769 aneurysms, 256 were unruptured: 202 were discovered in 145 patients with associated ruptured aneurysms, and 54 were discovered in 43 patients with no associated ruptured aneurysms. O f the 256 unruptured aneurysms, 250 were discovered incidentally, and six were symptomatic and of giant size. In this study, the patients were classified by age into three groups: 59 years or younger, 60 to 69 years, and 70 years or older. For these groups, a study was made o f (1) size and site o f aneurysms, (2) rupture rate of unruptured aneurysms, (3) follow-up study o f untreated unruptured aneurysms, and (4) surgical outcome for unruptured aneurysms. T h e rate o f rupture o f aneurysms at different sites was calculated by dividing the n u m b e r o f ruptured aneurysms at each location by the total n u m b e r o f a n e u r y s m s (both unruptured and ruptured) occurring at that location. The subjects o f our follow-up study were 47 patients with 55 unruptured aneurysms who were expectantly managed with no surgical treatment. T h e remaining 141 patients with unruptured aneurysms were either operated on (n -- 90), died soon after diagnosis (n -- 46), or excluded by other reasons (n = 5). T h e mean age o f this study g r o u p was 64 years (range 3 4 - 8 4 years). Eighteen patients with 20 unruptured aneurysms were no m o r e than 59 years old (mean 52 years), 11 patients with 11 aneurysms were 60 to 69 years old (mean 66 years), and 18 patients with 24 aneurysms were 70 years old or older 0090-3019/92/$5.00
Unruptured Intracranial Aneurysms in the Elderly
Surg Neurol 1992;38:364-70
365
Table 1. Size of Aneurysmsa Type of aneurysm
~4
5-9
10-14
15-19
20-24
->_25
Total
Unruptured Ruptured Total
139 (55) b 129 (25) ~ 268 (35)
87 (34) 264 (52) 351 (46)
18 (7) 81 (16) 99 (13)
3 (1) 13 (3) 16 (2)
0 (0) 3 (1) 3 (0.4)
6 (2) 19 (4) 25 (3)
253 (100) 509 (100) 762 (100)
Size of aneurysms is expressed in millimeters; number (%). The sizes of three unruptured and four ruptured aneurysms were not recorded. b Significance of difference, p < 0.01.
(mean 75 years). O f the 55 unruptured aneurysms, 34 were discovered in 29 patients with ruptured aneurysms that already had been clipped, and 21 were found in 18 patients with no associated ruptured aneurysms. The patients were followed up by personal consultations, telephone interviews, and letters. Information about possible new episodes o f subarachnoid hemorrhage and neurological symptoms were obtained from the patients or their close relatives. The follow-up period varied from 0.5 to 10.9 years, with an average of 5.1 years. The average follow-up period for patients aged 59 years or less, 60 to 69 years and 70 years or more were 5.2 years, 6.3 years, and 4.5 years, respectively. Direct operations for unruptured aneurysms were performed on 52 patients. Thirty-eight patients were 59 years old or younger, eight were 60 to 69, and six were 70 years old or older. O f the 52 patients, 30 had associated ruptured aneurysms that had been already clipped at least 1 month before the second surgery, and 22 had unruptured aneurysms alone. T h e surgical outcome 6 months after operation was assessed according to the Glasgow Outcome Scale [24]. Statistical analyses were done using the X 2 test. Results
Size and Site of Aneurysms Small aneurysms of 4 mm or less in diameter were significantly more c o m m o n in the unruptured aneurysm series than in the ruptured aneurysm series (Table 1). However, there was no significant difference among the
three age groups in the size of unruptured or ruptured aneurysms. Anterior communicating artery aneurysms were more common in the ruptured aneurysm series than in the unruptured aneurysm series (Table 2). Moreover, the incidence of unruptured anterior communicating artery aneurysms decreased with increasing age (Table 3). However, there was no significant difference in the site of unruptured aneurysms between the patients who had both ruptured and unruptured aneurysms and those who had unruptured aneurysms alone (Table 4). Table 5 shows the relationship between the site and size o f aneurysms. In the unruptured aneurysm series, the percentage o f small aneurysms o f 4 mm or less in diameter was the lowest in the middle cerebral artery; and in the ruptured aneurysm series, such small aneurysms were significantly more c o m m o n in the anterior communicating or distal anterior cerebral artery than in either the internal carotid or middle cerebral artery.
Rupture Rate of Unruptured Aneurysms In all of the three age groups, the highest rupture rate was observed in the anterior communicating artery aneurysms (Table 6). Furthermore, the rate of rupture o f the anterior communicating artery aneurysms increased with advancing age. Such a tendency was not observed in aneurysms at other sites.
Follow-up Study of Unruptured Aneurysms The sizes and sites o f the 55 unruptured aneurysms that were followed up are shown in Tables 7 and 8. The
Table 2. Site of Aneurysmsa Type of aneurysm
AComA
Distal ACA
ICA
MCA
VBA
Total
Unruptured Ruptured Total
24 (10) b 185 (37) b 209 (28)
28 (11) 30 (6) 58 (8)
96 (38) 134 (26) 230 (30)
83 (33) 133 (26) 216 (28)
21 (8) 24 (5) 45 (6)
252 (100) 506 (100) 758 (100)
Abbreviations: AComA, anterior communicating artery; ACA, anterior cerebral artery; ICA, internal carotid artery; MCA, middle cerebral artery; VBA, vertebrobasilar artery. Number (%). The sites of four unruptured and seven ruptured aneurysms were not recorded. b Significance of difference, p < 0.01.
366
Surg N e u r o l 1992;38:364-70
I n a g a w a e t al
T a b l e 3. Site of Unruptured Aneurysms in Three Age Groups ~ Age (yr)
AComA
Distal ACA
ICA
MCA
VBA
Total
-70
17 (13) b 6 (10) 1 (2) ~
16 (12) 5 (8) 7 (12)
49 (36) 18 (31) 29 (50)
43 (32) 23 (39) 17 (29)
10 (7) 7 (12) 4 (7)
135 (100) 59 (100) 58 (100)
Abbreviations: AComA, anterior communicating artery; ACA, anterior cerebral artery; ICA, internal carotid artery; MCA, middle cerebral artery; VBA, vertebrobasilar artery. Number (%). The sites of four aneurysms were not recorded. b Significance of difference, p < 0.05.
T a b l e 4. Site of Unruptured Aneurysms in Patients with Both Unruptured and Ruptured Aneurysms and with
Unruptured Aneurysms Alone a Patient classification
AComA
Distal ACA
ICA
MCA
VBA
Total
A B
17 (9) 7 (13)
24 (12) 4 (8)
70 (35) 26 (49)
70 (35) 13 (25)
18 (9) 3 (6)
199 (100) 53 (100)
Abbreviations: AComA, anterior communicating artery; ACA, anterior cerebral artery; ICA, internal carotid artery; MCA, middle cerebral artery; VBA, vertebrobasilar artery; A, patients with both unruptured and ruptured aneurysms; B, patients with unruptured aneurysms alone. ° Number (%). The sites of four unruptured aneurysms were not recorded.
T a b l e 5. Site and Size of Aneurysms a Ruptured aneurysms
Unruptured aneurysms Site of aneurysms AComA Distal ACA ICA MCA VBA
--10
3 1 12 9 2
(13) (4) (13) (11) (10)
-
