流行病学概况在1963年卒中列为美国第三位死亡原因。估计约有200万以上的人口曾经有过卒中而存活者。据美国心脏病学会报道,起源于颈动脉系统的卒中患者死亡率为20％,存活者在二年内的复发率达60％。颈动脉病变的临床结局不一,这是由于其有效的侧枝循环差异极大的缘故。最重要的侧枝为Willis氏环。在一般人口中,所谓正常形态的“环”约占15～ Epidemiological profile Stroke was listed as the third leading cause of death in the United States in 1963. It is estimated that more than 2 million people have had stroke survivors. According to the American College of Cardiology, the death rate from a stroke patient with a carotid-derived system is 20% and the survivors’ recurrence rate is 60% within two years. The clinical outcome of carotid artery disease is mixed, due to the significant differences in the collateral circulation. The most important branch is the Willis ring. In the general population, the so-called normal form of “ring” accounts for about 15 ~