Information
What is Arteriovenous Malformation (AVM)?
AVM is an anomaly in the brain's circulation, characterized by the direct transition of an artery to a vein, without a capillary bed in between (the artery and the vein, which is usually the case). The absence of capillaries in some parts of the brain causes dilated blood vessels. AVMs appear grossly as a 'tangle' of blood vessels.
脑动静脉畸形是一种先天性血管发育异常,导致动脉端与静脉端直接相通。脑动静脉畸形实际上是一团相互缠绕的管径大小不同的异常脑血管网,其内部脑动脉与静脉之间无毛细血管而直接沟通,并形成数量不等的异常血道。畸形的血管很脆弱脑动静脉畸形的血管团大小不等,团内的血管壁厚薄不匀,动脉壁的弹力纤维减少或没有,静脉壁更薄。
What are the causes of AVM?
AVM is usually a predisposed congenital condition.
脑动静脉畸形是一种先天性血管发育异常。
What are the effects of AVM?
AVMs are generally viewed as the most biologically aggressive of all the vascular malformations, possessing the greatest potential for massive haemorrhage. The progressive dilatation of the blood vessels in the brain would eventually cause them to rupture - haemorrhage. AVMs, less commonly, cause seizures.
由于畸形血管团中动静脉之间缺乏毛细血管,动脉血直接流入静脉,血流阻力骤然减少,导致局部脑动脉压下降、脑静脉压增高,并由此引发一系列血流动力学紊乱,是脑动静脉畸形出现脑出血的直接原因。大流量的血液使管壁结构异常的动脉扩张扭曲,血管壁进一步受损破坏,一旦不能承受血流压力时局部就会破裂出血。