<International Circulation>: What is the genesis of this dysfunction? Are there specific risk factors that we can isolate?
　　Dr Bairey Merz: Microvascular is related to risk factors although less than half of the prevalence is accounted for by traditional risk factors that we know (cigarette smoking， hypertension， dyslipidemia， diabetes， etc). It is not explained by diabetes which is the logical leap but it does not appear to be explained by diabetes. There is another whole dark side of the moon of microvascular dysfunction that we don’t what the etiologic pathways are. It may be primary problems of smooth muscle. It may be genetic polymorphisms. We have heard at this meeting about eNOS， nitric oxide pathways. We have done similar work in WISE and we have been able to demonstrate that a specific arginine flip does cull out endothelial dysfunction in women who otherwise have completely normal coronary arteries. So there are probably genetic pathways. We have also hypothesized that there are autonomic nervous system dysfunctional pathways. We think there are overlaps between this microvascular dysfunction and things like Takotsubos， which is believed to be a catecholamine storm， abnormal baroreceptor and autonomic nervous system response. So probably brain and neural pathways may also be involved and the research is ongoing.