Department of Neurology, Baylor College of Medicine, Houston, Texas, USA.
Neurosurgery. 2011 May;68(5):1164-71; discussion 1171. doi: 10.1227/NEU.0b013e31820edbd3.
The apparent paradox of natural history data suggesting low rupture risk of small asymptomatic aneurysms and the median size of aneurysm rupture remains unexplained. Aneurysm growth rates and their potential relationship with rupture risk have not been well examined in natural history studies.
To examine the question of whether small asymptomatic aneurysms ≤ 7 mm that are followed up over time rupture and to determine the relationship between aneurysm growth and rupture.
We reviewed all publications on unruptured aneurysms published from 1966 to 2009. We then selected all aneurysms ≤ 7 mm for which measurements were reported for at least 2 time points and for which initial asymptomatic status and ultimate outcome (rupture vs unruptured) were reported. Using the Mann-Whitney U test, we compared absolute diameter annual growth rate.
Our search retrieved 64 aneurysms. Thirty aneurysms ruptured during follow-up, of which 27 were enlarged before rupture (90%). Thirty-four aneurysms did not rupture, of which 24 enlarged during follow-up (71%). There was a statistically significant trend toward larger absolute diameter growth for ruptured aneurysms vs unruptured aneurysms (3.89 ± 2.34 vs 1.79 ± 1.02 mm; P < .001), respectively. Annual growth rates for aneurysms for the 2 groups, however, were not statistically different (27.46 ± 18.76 vs 32.00 ± 29.30; P = .92).
Small aneurysms are prone to growth and rupture. Aneurysm rupture is more likely to occur in aneurysms with larger absolute diameter growth, but rupture can also occur in the absence of growth. The annual growth rate in both groups suggests that rate of growth of aneurysms is highly variable and unpredictable, justifying treatment or close diagnostic follow-up.
自然病史数据表明，小的无症状的动脉瘤破裂风险较低，而动脉瘤破裂的中位大小仍未得到解释。在自然病史研究中，尚未很好地检查动脉瘤生长速度及其与破裂风险的潜在关系。
研究随着时间的推移，小的无症状的、直径≤7 毫米的动脉瘤是否会破裂，并确定动脉瘤生长与破裂之间的关系。
我们复习了 1966 年至 2009 年期间发表的所有未破裂动脉瘤的出版物。然后选择了所有至少有 2 个时间点的测量值报告，并且初始无症状状态和最终结果（破裂与未破裂）报告的直径≤7 毫米的动脉瘤。采用 Mann-Whitney U 检验，我们比较了绝对直径的年增长率。
我们的检索检索到 64 个动脉瘤。在随访期间，有 30 个动脉瘤破裂，其中 27 个在破裂前增大（90%）。有 34 个动脉瘤未破裂，其中 24 个在随访期间增大（71%）。破裂的动脉瘤与未破裂的动脉瘤的绝对直径增长率之间存在统计学上显著的趋势（分别为 3.89 ± 2.34 毫米与 1.79 ± 1.02 毫米；P<.001）。然而，两组动脉瘤的年增长率没有统计学差异（分别为 27.46 ± 18.76 毫米与 32.00 ± 29.30 毫米；P=.92）。
小动脉瘤容易生长和破裂。在绝对直径增长率较大的动脉瘤中，动脉瘤破裂更有可能发生，但在没有生长的情况下，也可能发生破裂。两组的年增长率表明，动脉瘤的生长速度高度可变且不可预测，这证明了治疗或密切诊断随访的合理性。
