未破裂脳動脈瘤の自然歴および治療リスクに関するEvidence
文献の報告をまとめると、まず破裂率に関しては、ISUIA以外の報告では未破裂脳動脈瘤年間破裂率は１〜２．３％とされています。ちなみにISUIAでは破裂動脈瘤に合併しないものでは、0.05%以下、合併するものでは0.5%という結果が出されています。
2002年度にISUIAでは前向き研究を学会報告し くも膜下出血に合併しない例でも7mm〜9mmの大きさのものの破裂率は年間0.7％、また10ミリ以上のものは1年目の破裂率が7％、25ミリ以上では17％と極めて高いことを修正報告しています。したがって特に大型の未破裂脳動脈瘤では注意が必要です｡
破裂をおきやすくする因子として、喫煙、大きさ、多発性、女性、後頭蓋窩、症候性のもの等が挙げられます。
治療リスクに関しては、一般に治療後の合併症率は4.2〜17.5%、死亡率は0.3〜3.8%と報告されています。治療成績を悪化させる因子として、年齢、瘤の大きさ、瘤の部位、多発性などが示唆されています。
（森田、桐野：EMBジャーナル10月号、2000 より改変）
表1：未破裂脳動脈瘤の診療に用いられる破裂率に関するEvidence
| Study, year | Case No Series No Follow-up | SAH cases | Rupture rate |
| Symptomatic cases | Factors ## | ||
| Juvela, 1993 | 142 Pt 181 Anmean 13.9yr | Y | 1%/yr |
| Y | Younger age(NS) Size*Grown* | ||
| Wiebers, 1987 | 130 Pt 161 Anmean 8.3 yr | N | 0<1cm 29%≧1cmfor all years |
| Y | Size* Older year(NS) |
||
| Yasui, 1996, 1997 | 234( of 360) Pt mean 75 months 1969〜1992 | Y | 25(6.9%) of 360 2.3%/ yr |
| ? | Multiple* | ||
| Rinkel, 1998 | 3907 Pt-Yr 9 series | Y | 1.9%/yr |
| Y | Symptomatic* Women* Larger* Posterior circulation* Additional(NS) |
||
| ISUIA Group 1, 1998 | 727 Pt 53 centers | N | 0.05%/yr < 1cm 1%/year ≧ 1cm |
| Y | Size* | ||
| ISUIA Group 2,1998 | 722 Pt 53 centersTotal 12023Pt-Yr | Y | 0.5%/yr < 1cm 1%/year ≧ 1cm |
| Y | None | ||
| Juvela, 2000 | 142Pt 181 Anmedian 19.7yr2575 Pt-Yr | Y Only 11;Non SAH | 1.3%/yr |
| Y(6) | Smoking (p=0.005)* Age (p=0.01)* Size (P-0.05)* |
#: JA; Journal Article, MA; Meta-Analysis, MS; Multicenter Study
##: Factors associated with increased risk of hemorrhage
* shown statistical significance(p<0.05)
表2：未破裂脳動脈瘤の診療に用いられる治療リスクに関するEvidence
| Study, year | Case NoSeries No | SAH cases | Surgery risk |
| Symptomatic cases | Factors## | ||
| Wirth, 1983 | 107 Pt 119 An12 centers | Y | Mortality: 0 Morbidity: 6.5% |
| N | Size Location (ACom,IC-Bif) | ||
| Solomon, 1994 | 202 Pt | Y | Mortality:0 Morbidity:7% |
| Y | Size | ||
| King, 1994 | 733 Pt 28 series | Y | Mortality: 1% (0.4〜2.0) Morbidity:4.1% (2.8〜5.8) |
| N | None | ||
| Raaymakers, 1998 | 2460 Pt 61 studies | Y | Mortality: 2.6% (2.0〜3.3) Morbidity: 10.9% (9.6〜12.2) |
| Y | Older publication* Giant * Posterior circulation* |
||
| ISUIA Group 1,1998 | 798 Pt 53 centers | N | Mortality: 3.8% Morbidity: 17.5%(1mo) 15.7%(1yr) |
| Y | Older age* | ||
| ISUIA Group 2,1998 | 197 Pt 53 centers | Y | Mortality:1.0%, Morbidity:13.6% (1mo), 13.1% (1yr) |
| Y | None | ||
| Orz, 2000 | 310 Pt | Y | Mortality 0.3% Morbidity:5% |
| Y | Size>15mm* Posterior circulation* Multiple * |
#: JA; Journal Article, MA; Meta-Analysis, MS; Multicenter Study
##: Factors associated with increased risk of surgical complication
＊shown statistical significance(p<0.05)
文献
- 1.
Juvela S, Porres M, Heiskanen O: Natural history of unruptured intracranial aneurysms.
J Neurosurg 79: 174-182, 1993.
- 2.
Wiebers DO, Whisnant JP, Sundt TM Jr, et al: The significance of unruptured intracranial
saccular aneurysms. J Neurosurg 66: 23-29, 1987.
- 3. Wirth FP, Laws ER, Jr, Piepgras DG, et al: Surgical treatment of incidental
intracranial aneurysms. Neurosurgery 507-511, 1983 .
- 4. Solomon RA, Fink ME, Pile-Spellman J: Surgical management of unruptured intracranial
aneurysms. J Neurosurg 80: 440-446, 1994
- 5. Orz YI, Hongo K, Tanaka Y, et al: Risks of surgery for patients with unruptured
intracranial aneurysms. Surg Neurol 53: 21-29, 2000 .
- 6. Rinkel GJE, Djibuti M, Algra A, et al.: Prevalence and risks of rupture of
intracranial aneurysms. A systemic review. Stroke 29: 251-256, 1998.
- 7. Raaymakers TWM, Rinkel GJE, Limburg M, et al.: Mortality and morbidity for unruptured
intracranial aneurysms. A meta analysis. Stroke 29: 1531-1538, 1998.
- 8. King JT, Berlin JA, Flamm ES: Morbidity and mortality from elective surgery for
asymptomatic, unruptured, intracranial aneurysms: a meta-analysis. J Neurosurg 81:
837-842, 1994.
- 9. King JT Jr, Glick HA, Mason TJ, et al: Elective surgery for asymptomatic unruptured ,
intracranial aneurysms: a cost-effectiveness analysis. J Neurosurg 83: 403-412, 1995.
- 10.
International Study of Unruptured Intracranial Aneurysms Investigators: Unruptured
Intracranial Aneurysms-risk of rupture and risks of surgical intervention. N Engl J Med
340: 1439-1442, 1998.
- 11. The New England Journal of Medicine report on unruptured intracranial aneurysms: a
critique. Surg Neurol 51: 227-229, 1999.
- 12. Raaymarkers TWM, MARS study group: Functional outcome and quality of life after
angiography and operation for unruptured intracranial aneurysms. J Neurol Neurosurg
Psychiatry 68: 571-576, 2000.
- 13. Juvela S, Porras M, Poussa K: Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture. J Neurosurg 93; 379-387, 2000
