Most doctors, although aware of "white coat syndrome" don't really care. If you have the increased BP when seeing the doctor, you are likely to have the same problem at other times during your normal day. I guess if you had an irrational fear of doctors this might be significant, but being stressed at the doctor is no different than being stressed at work, with the spouse, etc.
I actually have a rationally-based but extreme fear of doctors. In my case, since what I often have is abnormally low blood pressure, this means that sometimes at the doctor's office my blood pressure goes up to the normal range.
There is very little that can stress me out more than going to the doctor, because my lack of standard body language and facial expression has made dealing with medical problems a nightmare (I get accused of having psychiatric problems instead, but whenever they do tests they find that not only is the problem there but it's extremely severe by the time I know to complain about it -- this is what happens when your response to pain does not involve much if any change in body language or facial expression). I am developmentally disabled and my unusual behavior makes a lot of doctors confused about me and likely to do highly unpleasant things to me in the meantime. After a few instances in which one is derided, ridiculed, even sent home with Thorazine, and then has to get to the point of near-death before anyone catches anything (and has this happen over and over and each time the initial complaint proves legitimate), one starts to fear going to the doctor.