If you don't have intellectual-property protection, you might as well give it away. You may not make more money with it, but you won't make anything without it. The basic kinds of intellectual-property protection include trademarks, copyrights and trade secrets, as well as patents. The pharmaceutical industries and medical-products industries are very mature and very savvy in how they do business. Very often it goes well beyond just getting a patent.
Patents generally protect either a device or a method of use.
In Medtronic's case, the suit centered around the Wiktor stent, a device used to prop open previously clogged arteries. Some inventions are protected by numerous patents. Often a drug or device gets a new patent with each modification or improvement. They may not be great leaps, but there are modifications and improvements. Each time, you are able to amend and refile the case.