St. Jude files patent-infringement lawsuit against Volcano Corp.

Device maker St. Jude Medical Inc. (NYSE: STJ) is once again tangling with Volcano Corp., this time in a patent dispute over guide wires.

St. Jude has filed a lawsuit against Volcano, alleging that the San Diego company infringed on five patents related to its PressureWire technology platform for guide wires, according to a statement from Little Canada, Minnesota-based St. Jude. A guide wire is a metallic wire used to advance a catheter into a vein.

LightLab Imaging Inc., which was acquired by St. Jude in May for $90 million, is already embroiled in a legal dispute with a subsidiary of Volcano. In that case, a jury in February found that Volcano violated the terms of an exclusive contract with LightLab. Volcano said it would appeal.

The guide wire lawsuit involves Fractional Flow Reserve (FFR), an index used to evaluate the severity of blood-flow blockages in the heart. St. Jude’s PressureWire technology employs the FFR measure and the company apparently believes that Volcano’s PrimeWire does, too.

St. Jude said it has invested millions of dollars in clinical trials designed to support the use of FFR in interventional cardiology.

A Volcano spokeswoman didn’t immediately return a call.