It could indicate a lot of things...first, we'd need to know whether it was a regular stress test, or a nuclear stress test.
I failed my first nuclear stress test because I had a 99% blockage in a coronary artery and had to have a stent placed.
I failed a subsequent one about a year later because my breasts caused a shadow on the film.
Stress tests, both nuclear and "regular," can have both false positives and false negatives.
I would assume your doctor will be telling you pretty quickly what he/she thinks it means and what he/she recommends next. If not, I'd be on the phone insisting they tell me.