I believe the main difference is that the EU focuses on the risk as Dr. Simon mentioned in his lecture. Each classification based on the medical device directive is based on risk, so to an extent, the EU is taking notice of the potential dangers of the device. However, I believe most device companies would provide the research of showing the devices safety and efficiency even if it may not be required by the EU. Most medical device companies, who spend millions on research & development would want to sell their products in the USA, which is the #1 consumer in med devices where they could make the most money, so they would have to go through the 510k/PMA process provided by the FDA.