SAN FRANCISCO — The acquisition of privately-owned, venture capital-backed Ardian (Mountain View, California) in January 2011 by Medtronic (MDT; Minneapolis) for $800 million in cash upfront, plus commercial milestones equal to the annual revenue growth through the end of Medtronic's fiscal year 2015 sent shockwaves through the cardiology and medical device communities (Medical Device Daily, Dec. 1, 2010).