SAN FRANCISCO — Edwards LifeSciences says its competitor Medtronic won’t take yes for an answer.

Urging the U.S. Court of Appeals for the Federal Circuit to leave a controversial preliminary injunction in place, Edwards said in a filing Thursday it’s willing to let Medtronic supply its own artificial heart valves to patients who can’t be treated with Edwards’ patented version.

But instead of working together to modify the injunction so that all patients can be served, Medtronic has run to the Federal Circuit with “scare tactics” about lives put at risk, Paul, Weiss, Rifkind, Wharton & Garrison partner Catherine Nyarady wrote in response to Medtronic’s emergency motion to stay the injunction.

“Medtronic’s hyperbolic claims of patient care are just the latest example of its disingenuous attempts to flout the patent laws,” Nyarady wrote.

Edwards says its general counsel, Aimee Weisner, reached out to Medtronic acting GC Neil Ayotte during a recess at last Friday’s court hearing on the injunction, but was rebuffed. “Mr. Ayotte stated that Medtronic would not agree to any carve-out from an injunction and that Medtronic intended to continue its commercialization of the CoreValve products,” Weisner stated in a declaration filed with Edwards’ brief.

Medtronic fiercely contested the claim it’s been uncooperative in a reply late Thursday, detailing settlement proposals it’s made and filing a declaration from senior legal director Stephen Froehle stating he has, in fact, been conferring regularly with Weisner.

Medtronic argues a carve-out is unworkable because a physician’s judgment call about which device to use on a given patient is too complex to be reduced to bright-line rules. The mere threat of the injunction, scheduled to take effect next week, has already “caused cancellations of procedures that patients and their families were relying on,” Weil, Gotshal & Manges partner Edward Reines wrote for Medtronic.

Thursday’s filings are the latest development in a case that vividly sets a private company’s patent rights against public access to potentially lifesaving technology. At issue is the fast-growing market for artificial valves that can be inserted via the transfemoral vein and inflated into place inside the aorta, without open-heart surgery. Though the devices were first approved by the Food and Drug Administration only three years ago, the market is already estimated to be worth $500 million in the United States.

U.S. District Judge Gregory Sleet of Delaware on April 11 enjoined Medtronic from selling its valves, which a jury found—and the Federal Circuit has agreed—willfully infringed a version marketed by Edwards. Sleet acknowledged that Medtronic’s CoreValve product can be used on a wider variety of patients, and that it’s “safer” and leads to “better outcomes with a lower risk of death.”

“At the same time,” Sleet said, “the court cannot downplay the strong public interest favoring enforcement of patent rights.”

He gave the parties six weeks to work out some kind of “mechanism” that will let physicians choose either device based on their clinical judgment of individual patient need. But the injunction takes effect April 22. If the Federal Circuit doesn’t stay it, Medtronic advised the Federal Circuit, “treatable patients may unnecessarily die in the name of already expired patent rights.”

On Tuesday, Sleet issued a written ruling expanding on his reasons—and his criticisms of Medtronic’s “egregious conduct”—while appearing to walk back the injunction slightly.

Sleet says Medtronic misrepresented to the court in 2010 that an injunction would be futile because the company was moving its CoreValve manufacturing out of the United States to Mexico. Instead, the company was actually ramping up U.S. production, Sleet contends.

“Medtronic disregarded the law in infringing Edwards’ patent and boldly continued to thumb its nose at the law by continuing its conduct even after being found to be a willful infringer,” Sleet wrote. “The court cannot ignore the fact that it would serve as a reward of sorts to Medtronic and an incentive for onlookers to behave as Medtronic has should the court permit Medtronic to freely commence sales of its device.”

Medtronic said Thursday it never promised to shut down U.S. production immediately, and by 2012, 90 percent of production had been shifted to Mexico.

As for the public interests at play, Sleet wrote doctors “must be permitted” to implant the Medtronic devices when patients’ aortas are so enlarged they can’t be fitted with the Edwards device. “The preliminary injunction must be tailored to the present circumstances and the considerable public interest at issue,” Sleet wrote.

The companies aren’t close to agreeing on how many patients such an exception would cover. Edwards puts it at about 750 per year while Medtronic estimates it’s closer to 5,000.

The judge’s decision followed a daylong evidentiary hearing in which Medtronic’s lawyers at Keker & Van Nest and Edwards’ at Paul Weiss grilled medical experts about the merits of Edwards’ Sapien valve, which uses a balloon to expand, versus a self-inflating valve like Medtronic’s.

“We believe that balloon-expandable is going to be the market share leading platform,” Edwards Vice President Larry Wood said under cross-examination by Keker & Van Nest partner Robert Van Nest. “But this market is so significant in size that even if self-expanding was a minority of the market, it’s still a very large opportunity and it’s an opportunity we would also like to participate in.”

“And I assume you would like to have it available for patients, too?” Van Nest asked.

Judge Sleet said in his opinion he was impressed with the testimony of University of Michigan physician George Michael Deeb, who said both companies’ heart valves are excellent, but physicians ought to be free to decide which to use on a given patient. “There are so many factors and so many permutations of factors that you can’t take it down to a simple formula,” he said.

Contact the reporter at sgraham@alm.com.