Co-Founder at Playerize
Very little. At the angel/seed stage, they're investing in the founders, so there's no expectation of patents, etc... They might check that you're incorporated in good standing, and ensure you have a solid startup/corporate lawyer, and have good employment and IP ownership agreements with your staff and contractors, and that's about it.
I know some accelerators and angels (eg. Vancouver's GrowLab) actively seek founders from other countries - they've had mutliple startups come through from Romania for example. Also, 500Startups is working very hard to expand internationally, even launching programs in India, etc. Reach out to those organizations.