Not anymore since the health care law was passed. Pre-existing conditions aren't grounds for jack anything anymore come 2013, and aren't going to lock you out of insurance now. A little high blood pressure? Please that's a totally minor problem anyhow. However years of high blood pressure left untreated can severely damage your body or you might even stroke out!
Go to the doctor for your problems. Medical problems are best solved early. Then you often have non-medical solutions available too.
The law can still be repealed. Incoming Speaker John Boehner said (yesterday or today) it's a priority of his, and most, if not all, of the new Republican congressmembers promised to repeal the bill or parts of it.
OT, but I can't help myself. It's a priority of the GOP to bring health care repeal to a vote. That way they all get their Obamacare creds without having to actually fix anything.
If they want to actually repeal health care, they are going to have to wait until they have a Republican president, or a veto-proof majority, which won't happen until 2012 at the earliest. There may not be repeal momentum left at that point.
Slightly more on-topic, having things like this on your medical record is a concern, but I think keeping one's good health should always be more important than insurance details that may or may not make any difference.
Go to the doctor for your problems. Medical problems are best solved early. Then you often have non-medical solutions available too.