Shares of medical device maker Medtronic Inc fell as much as 6 percent after a U.S. court temporarily halted sales of its aortic heart valve replacement system in the country.
The ruling, by the Federal District Court of Delaware on Friday, was made following earlier court decisions that found Medtronic's CoreValve to have infringed on rival Edwards Lifesciences Corp's transcatheter heart valve patents.
Edwards Lifesciences shares rose as much as 16 percent in early trading to their highest in nearly a year.
The court agreed to postpone implementation of the ruling for seven days to allow Medtronic to appeal.
The court also ordered both companies to come to an agreement that would help physicians at facilities currently trained on CoreValve to make a clinical judgment as to which device to implant.
Analysts said the ruling came as a surprise and that the court would still have to weigh the injunction against the "public interest."
"How does a judge take a product off the market that has shown an ability to reduce mortality?" J.P. Morgan analysts wrote in a note to clients.
Medtronic's CoreValve system for replacing diseased aortic heart valves led to a significantly higher survival rate after one year than traditional open heart surgery in patients deemed at high risk of death during surgery, according to data the company presented at a conference in March.
CoreValve won U.S. approval in January to treat patients deemed too frail to endure open heart surgery, becoming the first such device to compete against Edwards Lifesciences' Sapien valve in the United States.
Medtronic shares were down 2 percent at $57.86 in morning trade on the New York Stock Exchange, while those of Edwards were up 14 percent at $83.22. (