The European Patent Office invalidated an Edwards Lifesciences Corp. patent that was used to prevent Medtronic Inc. from selling its Core­Valve transcatheter aortic valve in Germany, Medtronic said Thursday.

Edwards last August won an injunction in a German court that found the CoreValve violated the Edwards patent. But after the European Patent Office questioned the patent’s validity, another German court in November voided the initial ruling.

In the latest move, the patent office said the entire patent, called the Spenser patent, is invalid and revoked it.

“Medtronic is very pleased with this ruling as it will ensure that patients across Europe who need aortic valve replacement will have access to this lifesaving therapy,” John Liddicoat, a Medtronic senior vice president and president of its structural heart business, said in a statement.

Medtronic and Edwards are the two biggest players in sales of transcatheter aortic valves. They also are no strangers to patent litigation, both in Europe and the United States. In January, a federal court jury in Delaware ruled that Medtronic’s Core­Valve infringed on another Edwards patent, known as the Cribier patent. The jury held Medtronic liable for $393.6 million in damages.

Medtronic said it would appeal the Delaware verdict.

The CoreValve System was cleared for sale in Europe in 2007. The U.S. Food and Drug Administration in January approved the device for sale in the U.S. to patients considered at extreme risk for open heart surgery. Medtronic expects FDA approval to use Core­Valve on high risk patients later this year.

Transcatheter aortic valve replacement, or TAVR, is a less invasive way to replace diseased aortic valves. Aortic valve stenosis is a deadly narrowing of the aortic valve that obstructs blood flow from the heart. Half of those patients with aortic valve stenosis die within two years of diagnosis. An estimated 150,000 patients are diagnosed with aortic stenosis each year. One-third to one-half of those patients do not get surgery.

Some patients are considered too sick to endure the trauma of having their chests cracked open. TAVR allows doctors to insert a new valve into the heart by snaking a catheter up into the patient through an artery in the leg or through an incision in the upper body. Patients can be home from the hospital within a couple of days.