Ok, I was able to find a great many abstracts for the sources cited in that article. The side effects ones were reviews of the availible ifo on studies into creatine safety.

Wasn't able to find anything about high blood pressure. The closest I could get was a story about a bodybuilder who had an ischemic stroke after taking Ma Huang, creatine and some other stuff like L-Carnitine for a while. Ma Huang = ephedra. I dont know of the guy had high blood pressure.

I found one study that examined the blood pressure of it's participants and found no effect.

If you google "effect of creatine on blood pressure" you'll get a lot of stuff.

Apparently there is no clinical evidence that creatine causes high blood pressure. Only anecdotal reports. The ideal that it might is based on the fact that it increases water retention and so may effect blood pressure in a similar way to sodium. Again, there is no evidence that this is true.