ATS is one of the 'spin off's' of the St. Jude Mechanical Valve, along with the Carbomedics Valve.
Pyrolytic Carbon which is the material used for the leaflets was invented by Jack Bokros, Ph.D., for an application in the Nuclear Power industry. Somehow he learned about heart valves and realized that his material offered several advantages over the older designs, especially the Ball in Cage designs, hence the creation of the St. Jude Valve some 30 years ago.
He has been designing Heart Valves ever since. He later founded the Medical Carbon Research Institute and used his 'latest and greatest' material to produce the On-X Valves which were introduced to the world market in 1996.
The people at On-X can tell you all you would ever want to know (and more !) about any of those Mechanical Valves. See www.onxvalves.com or www.heartvalvechoice.com or call 1-888-339-8000.
It is my understanding that the ATS and Carbomedics Valves were originally created for foreign markets but eventually were released as independent offerings in the USA.