Boston Scientific Corp., the second-largest maker of heart devices, was ordered by a federal jury to pay $250 million to Medtronic Inc. for infringing patents on catheters used to install stents and break up blockages.

The jury in Marshall, Texas, delivered its verdict Tuesday after a weeklong trial and concluded that the infringement was intentional, giving U.S. District Judge T. John Ward the option to increase the award by as much as three times to $750 million. Medtronic may seek an injunction halting sales of the infringing products, said Marybeth Thorsgaard, a company spokeswoman.

"Any time you're dealing with medical devices that affects people's lives, the jury is incredibly interested," said Sam Baxter, an attorney who represented Fridley-based Medtronic. "It touches them or people that they're close to."

Medtronic, the world's largest maker of heart-rhythm devices, had claimed Boston Scientific violated patents related to balloon catheters and guidewires. Boston Scientific, based in Natick, Massachusetts, denied infringing the patents.

Matthew Wolf, an attorney for Boston Scientific, said he was "disappointed in the result." Medtronic was challenging Boston Scientific's Taxus Express2, Express2, Liberte, Maverick, Maverick2 and Quantum Maverick products.

Boston Scientific reported a net loss of $495 million last year on sales of $8.36 billion. Medtronic posted net income of $2.23 billion in the fiscal year through April on sales of $13.5 billion.

Today's verdict is the nation's sixth-largest this year, and the third-largest patent verdict of 2008. Boston Scientific lost a patent case earlier this year in Marshall when it was told to pay a New Jersey doctor $431 million.

The Medtronic patents cover angioplasty catheters with narrowed distal ends, and semicompliant angioplasty balloons, which provide strength to withstand repeated inflations allowing custom vessel sizing, the company said in a statement.