St. Jude Medical (NYSE:STJ) researchers implanted the 1st patient with a larger-sized Portico transcatheter aortic valve as part of the medical device maker’s ongoing Portico TF EU trial.

The trial was launched to evaluate the 23 mm valve and has been expanded to include the 25 mm valve as well. The data from the study will support a bid for European regulatory approval for the Portico valve, according to a press release.

St. Jude plans to implant up to 50 patients in the 25 mm arm of the trial, which cardiovascular & ablation technologies president Frank Callaghan called "another major milestone" for the company’s TAVI program.

The healthcare giant in November 2012 won CE Mark approval in the European Union for its Portico TAVI system, pitting St. Jude against Edwards Lifesciences (NYSE:EW) and arch-rival Medtronic (NYSE:MDT) in the TAVI market across the pond.

St. Jude now faces a pair of entrenched competitors in Europe and another rival, Boston Scientific(NYSE:BSX), waiting in the wings along with several smaller contestants.

Medtronic’s CoreValve TAVI was first to market, hitting European shelves in 2007. Edwards Lifesciences wasn’t far behind, putting its Sapien TAVI in the EuroZone a few months later and beating CoreValve to the U.S. market late last year.

California-based Direct Flow Medical joined the game this year, landing CE Mark approval for a metal-free TAVI system that the company says "virtually eliminates aortic regurgitation."