<International Circulation>:In recent years， attempts to explore the value of blood pressure levels closer to the heart， the so called central blood pressures， suggests that noninvasive measurements of central aortic blood pressures may have benefit. Doctor， would you please introduce the basics of central blood pressure measurements?

      Prof.Bakris:Well， central blood pressure is really the pressure that the heart， the brain， and the kidney see because it’s the pressure in the aorta. And because the aorta is a big tube and its pumping blood out into smaller tubes， the smaller tubes are of course going to have higher resistance. So if you are measuring brachial blood pressure that’s a much smaller tube than the central large artery and the more pliable the vessel is the less likely there is to be a difference. The stiffer the vessel is the more likely there is to be a difference. And of course these people using wrist cuffs that are measuring blood pressure at the radial artery are going to get even more inaccurate data. And actually inaccurate in the sense that those pressures are going to be higher than what the central pressure is. The danger is that if you start treating those pressures， especially in the elderly or people with very stiff vessels， you’re going to further reduce the central pressure which already may be lower. And by doing that， the brain may not see the pressure it’s normally wanting to see and likewise you may get lightheaded or you may get dizzy or you may have those kinds of symptoms， that’s not for sure， that’s at this point a hypothesis. Gary Mitchell has shown that very little differences in hyperdynamic circulation there may be greater differences but I think that this is all still investigational and still needs to be sorted out better.