Medical device maker Medtronic has recalled 7,300 devices used to implant heart valves, including 540 in the United States, after receiving reports that the systems contained particles that could cause health problems.

The Evolut R transcatheter ­aortic valve and the special kit used to implant it were approved for ­commercial sale domestically last June. In the U.S., only systems that were intended for use in clinical ­trials by the Minnesota-run device firm were recalled.

"In the U.S., no affected loading systems had been released commercially. All of the affected loading systems have already been removed from the market," Medtronic spokeswoman Wendy Dougherty said in an e-mail Friday. "Most importantly, there had been no reports of any adverse patient effects due to this issue and no further action is required of health care professionals."

She cautioned that the recall affected just the 74 product lots listed in the notice sent to doctors last month. On Wednesday, the Food and Drug Administration characterized the letter as a Class I recall because the agency decided there was a reasonable probability of adverse health consequences if the device is used.

The Evolut R is among a high-growth class of devices called transcatheter aortic valve replacements, which allow doctors to implant new heart valves without open-chest ­surgery. The valves are folded up inside a narrow tube that is advanced to the heart from an incision in the leg. It's approved to treat patients whose aortic valves are so severely narrowed that they limit the flow of blood through the heart, potentially leading to heart failure.

The valve itself was not recalled. Rather, Medtronic's "Urgent Field Safety Notice" — posted online by German regulators — says the company received eight reports of ­particulate matter in the EnVeo R Loading System that is used to implant the valve in the heart.

"While Medtronic has received only eight reports of particulate identified from the loading system, with no reports of adverse patient effects, bench testing has demonstrated a higher prevalence of particulate and the potential for its transfer to the TAV," or transcatheter aortic valve, the safety notice says.

The particles could have caused a blockage in a patient's blood stream called an embolism, the letter days. Dougherty wrote that the issue has since been resolved "with the introduction of a process improvement in ­manufacturing."

Joe Carlson • 612-673-4779

Twitter: @_JoeCarlson