Cordis Corp. and Wyeth sued a pair of medical device giants, Abbott and Boston Scientific Corp., alleging infringement of a coatings patent for coronary stents.

It’s the latest chapter in the never-ending stent wars, which have seen a number of lawsuits and settlements in recent months.

A small version of Cordis Corp.‘s Cypher drug-eluting stent won approval from the Food & Drug Administration for treating blockages in small blood vessels.

The Bridgewater, N.J.-based Johnson & Johnson subsidiary said the federal watchdog’s approval of its 2.25mm Cypher sirolimus-eluting coronary stent was based on a quartet of studies comparing it to bare-metal stents.

Boston Scientific Corp. returned fire to Medtronic and Abbott, aiming to counter the rivals’ claims that their stents outperform BoSci’s older Taxus model.

Abbott threw another grenade Boston Scientific‘s way with a study showing its Xience V drug-eluting stent outperforms BoSci’s Taxus.

The news follows a Medtronic study that company touted earlier today, showing that its Endeavor stent is safer than the Taxus.

Medtronic Inc. lobbed another grenade in the ongoing stent wars, touting a long-term study it says shows that its Endeavor drug-eluting stent is safer than rival Boston Scientific Corp.‘s Taxus.

Medtronic said the three-year results from the Endeavor IV trial comparing its zotarolimus‐eluting stent and BoSci’s paclitaxel‐eluting stent in 1,548 patients show a nearly 50 percent reduction in the risk of heart attack or cardiac death with the Endeavor stent.

Boston Scientific Corp. enrolled more than 1,500 patients in the Platinum clinical trial of its Promus Element drug-eluting stent, two months ahead of schedule, setting the stage for approval applications to the Food & Drug Administration and the Japanese Ministry of Health, Labor and Welfare.

The Natick, Mass.-based medical devices giant said the workhorse trial is a global, randomized, pivotal controlled study of its platinum chromium Promus Element everolimus-eluting stent involving 1,532 patients at more than 140 sites worldwide.

Abbott said it’s planning a fourth-quarter launch for its Xience V everolimus-eluting coronary stent (PDF), after the Chinese State Food and Drug Administration approved the device to treat coronary artery disease.

Abbott Laboratories opened up a new front in the long-running stent wars, with the official launch of its Xience Prime drug-eluting stent in Europe.

The announcement was made at the European Society of Cardiology Congress in Barcelona, Spain. Chicago-based Abbott received CE Mark approval for the device in June.