Don't believe the hype.
It's certainly possible that at some point the Chinese could stop buying U.S. debt and, therefore, drive up interest rates. But every time I ask the question of true experts in the field (as opposed to inside-the-Beltway types who are interested in scoring political points), I get an answer that makes far more sense and is based on facts rather than fear-mongering.
Chuck Lieberman, who as I've said before is one of the economists whose words I always consider carefully, has an easy-to-read take on this issue that is worth a few minutes of your time.
If you don't have time to read the whole thing, here's the money quote: