St. Jude Medical Inc. said Tuesday that it has filed a patent infringement lawsuit against a California company that has developed a diagnostic tool and imaging catheters that hospitals use to determine the severity of disease in the arteries.

The suit, filed in U.S. District Court in Delaware, alleges that several products distributed by San Diego-based Volcano Corp., including PrimeWire pressure guide wire products, infringe on five St. Jude patents. The PrimeWire technology, which St. Jude acquired for $250 million from Radi Medical Systems two years ago, measures the severity of blockages leading to the heart.

The suit seeks injunctive and monetary damages.

The lawsuit filed Tuesday follows St. Jude Medical's recent acquisition of LightLab Imaging, Inc., which is already engaged in litigation against Volcano, and its wholly owned subsidiary, Axsun Technologies Inc., a supplier to LightLab.

Earlier this year, a jury in Massachusetts Superior Court reached a verdict against Volcano and Axsun Technologies, St. Jude said.

Fridley-based Medtronic Inc. was an investor in Volcano before it went public four years ago and continues to engage in various strategic partnerships with the company. Representatives from Volcano could not be reached for comment on any of the lawsuits filed against it by St. Jude.

Two former St. Jude executives serve on Volcano's board, including former Chairman and CEO Ronald Matricaria and a former president of its Cardiac Rhythm Management division, Michael Coyle.

JANET MOORE