N Engl J Med. 2012 Jun 28;366(26):2474-82. doi: 10.1056/NEJMoa1113260.
The natural history of unruptured cerebral aneurysms has not been clearly defined.
From January 2001 through April 2004, we enrolled patients with newly identified, unruptured cerebral aneurysms in Japan. Information on the rupture of aneurysms, deaths, and the results of periodic follow-up examinations were recorded. We included 5720 patients 20 years of age or older (mean age, 62.5 years; 68% women) who had saccular aneurysms that were 3 mm or more in the largest dimension and who initially presented with no more than a slight disability.
Of the 6697 aneurysms studied, 91% were discovered incidentally. Most aneurysms were in the middle cerebral arteries (36%) and the internal carotid arteries (34%). The mean (±SD) size of the aneurysms was 5.7±3.6 mm. During a follow-up period that included 11,660 aneurysm-years, ruptures were documented in 111 patients, with an annual rate of rupture of 0.95% (95% confidence interval [CI], 0.79 to 1.15). The risk of rupture increased with increasing size of the aneurysm. With aneurysms that were 3 to 4 mm in size as the reference, the hazard ratios for size categories were as follows: 5 to 6 mm, 1.13 (95% CI, 0.58 to 2.22); 7 to 9 mm, 3.35 (95% CI, 1.87 to 6.00); 10 to 24 mm, 9.09 (95% CI, 5.25 to 15.74); and 25 mm or larger, 76.26 (95% CI, 32.76 to 177.54). As compared with aneurysms in the middle cerebral arteries, those in the posterior and anterior communicating arteries were more likely to rupture (hazard ratio, 1.90 [95% CI, 1.12 to 3.21] and 2.02 [95% CI, 1.13 to 3.58], respectively). Aneurysms with a daughter sac (an irregular protrusion of the wall of the aneurysm) were also more likely to rupture (hazard ratio, 1.63; 95% CI, 1.08 to 2.48).
This study showed that the natural course of unruptured cerebral aneurysms varies according to the size, location, and shape of the aneurysm. (Funded by the Ministry of Health, Labor, and Welfare in Japan and others; UCAS Japan UMIN-CTR number, C000000418.).
未破裂脑动脉瘤的自然史尚未明确界定。
2001 年 1 月至 2004 年 4 月期间，我们在日本招募了新诊断为未破裂脑动脉瘤的患者。记录动脉瘤破裂、死亡和定期随访检查的结果。我们纳入了 5720 名年龄在 20 岁及以上（平均年龄 62.5 岁，68%为女性）的患者，这些患者有最大直径为 3 毫米或以上的囊状动脉瘤，最初表现为仅有轻微残疾。
在研究的 6697 个动脉瘤中，91%是偶然发现的。大多数动脉瘤位于大脑中动脉（36%）和颈内动脉（34%）。动脉瘤的平均（±SD）大小为 5.7±3.6 毫米。在包括 11660 个动脉瘤年的随访期间，有 111 名患者发生了破裂，破裂年发生率为 0.95%（95%置信区间[CI]，0.79 至 1.15）。动脉瘤破裂的风险随动脉瘤大小的增加而增加。以 3 至 4 毫米大小的动脉瘤为参照，大小分类的危险比如下：5 至 6 毫米，1.13（95%CI，0.58 至 2.22）；7 至 9 毫米，3.35（95%CI，1.87 至 6.00）；10 至 24 毫米，9.09（95%CI，5.25 至 15.74）；25 毫米或更大，76.26（95%CI，32.76 至 177.54）。与大脑中动脉的动脉瘤相比，后交通和前交通动脉的动脉瘤更易破裂（危险比分别为 1.90（95%CI，1.12 至 3.21）和 2.02（95%CI，1.13 至 3.58））。有子囊（动脉瘤壁的不规则突起）的动脉瘤也更容易破裂（危险比为 1.63；95%CI，1.08 至 2.48）。
本研究表明，未破裂脑动脉瘤的自然病程随动脉瘤的大小、位置和形状而变化。（由日本厚生劳动省和其他机构资助；UCAS Japan UMIN-CTR 编号，C000000418。）
