Medical Device Committee
The FDA have produced draft guidance on this topic and if you search on the FDA website you should be able to find the following title:
"Acceptance of Medical Device Clinical Data from Studies Conducted Outside the United States".
Whilst the guidance indicates that studies conducted outside the US may be accepted, experience suggests that in reality it can be very difficult to get the FDA to accept studies conducted outside the US.
The best advice is to read the guidance carefully and then discuss your study strategy directly with the FDA before committing to the study. The FDA are generally willing to discuss proposed studies and will give an indication if they would consider the proposals acceptable.