International Circulation: What method should be used in assessment of intracranial arterial disorders?

　　David Wang: That is an interesting question because currently we are trying to figure out who are the people who will be at risk to develop stroke， that is the ultimate event that you try to prevent. So intracranial atherosclerotic disease is a known risk factor for stroke. The problem is to what degree the stenosis， is it 50% or 90% that places the patient at risk for stroke. It is something that is still unclear， to measure the degree of stenosis there is a good methodology and method to evaluate people for risk if the patient has sclerotic disease. A large sclerotic disease like coronary artery disease， the risk is higher if you have a higher degree of stenosis. Should you use the same principals for people with intracranial arterial stenosis? We are not quite sure because for example in trials， there is certain degrees seen in a number of patients， patients with 60% stenosis actually have higher degree and chance of having stroke while there are patients with 80% who have a lower chance of stroke so that means when you have intracranial atherosclerotic disease using the degree of stenosis to evaluate the risk is maybe a little too simple and may not be as accurate so therefore there are other ways of evaluating such risk. For example， we can now check out the hemodynamics and surrounding stenosis. We should also check the collaterals， that means the area of stenosis could be any other vessel in the network.  Without networking， without collaterals， maybe you have a higher risk. Other ways to evaluate people at risk would be perfusion and blood flow studies. Lastly， we can evaluate the plaque itself. Atherosclerotic plaque may be another good way of looking at intracranial arterial stenosis. Obviously the brain is slightly different than anywhere else because there are smaller vessels in the head that are losing certain layers， such as the elastic layer. When we lose the elastic layer， then when we form the atherosclerotic plaque the characteristics of the plaque and the chance of forming a thrombosis is maybe a little different from the plaque in other vessels. Using the way of detecting the degree of stenosis and the intracranial arteries is maybe one of the ways of evaluating patient’s risk of stroke but it may not be the only way. Maybe there are other ways.

　　《国际循环》：评估颅内动脉疾病的方法有哪些？

　　David Wang教授：这是一个非常有趣的问题，因为我们真的在努力寻找哪些卒中高危人群，进而预防最终卒中事件的发生。颅内动脉粥样硬化性疾病是卒中的已知危险因素。但问题是，到底何种程度的狭窄，颅内动脉狭窄50%还是90%时患者才具有较高的卒中发生风险。目前，这一问题尚无确切答案。对患有颅内动脉粥样硬化性疾病的患者，我们已经有了很好的方法来评估其卒中风险。对较大的粥样硬化性疾病如冠状动脉疾病而言，动脉狭窄越严重，患者卒中风险越高。这种情况是否适用于颅内动脉狭窄患者？对此，我们还不是非常清楚。因为有试验发现，一些狭窄程度仅为60%的患者即存在较高的卒中风险，而有些狭窄80%的患者卒中风险却更低。这提示，对伴有颅内动脉粥样硬化性疾病的患者而言，采用狭窄程度来评估卒中风险可能还是有些过于简单了，也不是太准确，因此我们需要采用其他方法来评估其卒中风险。例如，我们可以检查患者的血流动力学及周围狭窄情况以及侧支循环情况。如果没有侧支循环的话，可能患者就会面临较高的卒中风险。此外，我们还可以通过灌注及血流研究来评估患者的卒中风险。最后，我们还可以对斑块本身进行评估。动脉粥样硬化斑块可能是寻找颅内动脉狭窄的一种非常好的方法。很显然，与其他部位相比，大脑是略有不同的，因为头部的血管更为细小，没有弹性层等特定血管层。与其他血管不同，血管缺乏弹性层时一旦形成动脉粥样硬化斑块，则斑块的特点及发生血栓的几率都有所不同。评估颅内动脉的狭窄程度可能是评估患者卒中风险的一种方法，但肯定不是唯一方法。我们还有很多其他方法可用。