Mitchell P, Jakubowski J
Department of Neurological Surgery, N Floor, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
J Neurol Neurosurg Psychiatry. 2000 Dec;69(6):760-7. doi: 10.1136/jnnp.69.6.760.
The recent publication of the results of the international study on unruptured intracranial aneurysms highlighted a paradox: there do not seem to be enough unruptured aneurysms in the population to account for the observed incidence of subarachnoid haemorrhage. Some authors have suggested that the answer to this paradox is that most aneurysms that bleed do so shortly after formation. This would mean that the bulk of subarachnoid haemorrhages come from recently formed rather than long standing aneurysms. This paradox and proposed answer are examined. The available statistics on the incidence of subarachnoid haemorrhage, the prevalence of unruptured aneurysms, and the risk of bleeding from unruptured aneurysms are used to place a maximum on the time interval between aneurysm formation and rupture. For aneurysms less than 10 mm in diameter in persons with no history of subarachnoid haemorrhage, an estimate of less than 42 weeks was made. The null hypothesis that such aneurysms pose a constant risk with time is rejected with p <10(-9). In larger aneurysms the risk seems to be constant with time.
近期关于未破裂颅内动脉瘤的国际研究结果公布，凸显了一个矛盾之处：人群中未破裂动脉瘤的数量似乎不足以解释观察到的蛛网膜下腔出血发病率。一些作者认为，这个矛盾的答案是大多数出血的动脉瘤在形成后不久就会出血。这意味着大部分蛛网膜下腔出血来自新形成的动脉瘤，而非长期存在的动脉瘤。本文对这一矛盾及提出的答案进行了探讨。利用蛛网膜下腔出血发病率、未破裂动脉瘤患病率以及未破裂动脉瘤出血风险的现有统计数据，来确定动脉瘤形成与破裂之间的最大时间间隔。对于无蛛网膜下腔出血病史的直径小于10毫米的动脉瘤，估计时间间隔小于42周。时间对这类动脉瘤出血风险无影响的原假设被拒绝，p值<10(-9)。对于较大的动脉瘤，其风险似乎随时间保持恒定。
