I'm just wondering, if you get a blood clot in the leg (vein), can it cause a stroke (artery)?

Rarely: While it is possible for a vein blood clot to travel to the artery side of things, it would have to do this through a hole in the heart, termed an septal defect. This tests to be rare but can be diagnosed by an ultrasound est looking at the heart. I hope this helps.

Paradoxical stroke: As dr. Santin said, it is possible but fairly rare. Although 25-30% of the population has the septal defect in their heart that he mentioned, it rarely causes trouble when it is there. As a result, we don't routinely look for it, unless someone has had a stroke and, especially, if they are young and don't have other risk factors for having had a stroke.