UPDATE 2-US FDA staff-Medtronic heart valve study met goals

* FDA panel to review Melody device on Wednesday

* Valve system less invasive than traditional valves

* Panel will be asked about device fractures (Recasts; Adds company comments, share price)

By Lisa Richwine

WASHINGTON, July 20 (Reuters) - An experimental Medtronic Inc (MDT.N) replacement heart valve met safety and effectiveness goals in a key study of patients born with heart defects, U.S. reviewers said in documents released on Monday.

Food and Drug Administration staff said they would ask an advisory panel, however, about fractures found in a part of the Melody heart valve device in some patients.

The product is a new type of valve implanted through less invasive means than traditional valves that require open-heart surgery. The valve is designed for patients born with heart defects that disrupt blood flow from the right ventricle to the pulmonary artery. It can be implanted by threading a tube through a leg vein to the heart.

A panel outside experts will review data on Wednesday and make recommendations about whether the device should be approved. The FDA usually follows panel advice.

In a summary prepared for the panel, FDA reviewers said the device met key goals is a Medtronic study that measured rates of successful implantation, death and serious complications.

The FDA staff, however, said they would ask the panel about the significance of fractures seen in tiny mesh tubes known as stents that are used in delivery of the valve.

A Medtronic study in U.S. patients found an 18 percent stent fracture rate, FDA reviewers said. Five of 16 patients with the fractures required a repeat procedure.

Medtronic, in a separate summary released by the FDA, said the device was intended for a small group of patients, many of them young, who have previously undergone open-heart surgery and likely will need it repeated.

Use of the Melody device may delay or prevent future surgeries, potentially reducing the number of open-heart operations over a lifetime, the company said.

Data provide "strong evidence" the Melody system "provides a probable benefit to health that outweighs the risk of injury or illness from its use," the company said.

Medtronic is seeking approval under an exemption that allows devices to be used in up to 4,000 patients per year should manufacturers demonstrate a probable benefit without unreasonable risk of harm.

If the FDA approved the device, it could help Medtronic build a presence in the relatively new market for less-invasive valve replacement, known as transcatheter replacement. Edwards Lifesciences Corp (EW.N) pioneered the technology for use in aortic valves, and Johnson & Johnson (JNJ.N) also is looking to compete in the area.

In February, Medtronic announced it was buying two privately held heart valve companies including CoreValve, a major player in transcatheter heart valve technologies.

The Melody valve already is approved in Europe and Canada.

Medtronic shares were up 2 cents to $34.69 in afternoon trading on the New York Stock Exchange.

The FDA and Medtronic documents were posted here. (Reporting by Lisa Richwine, editing by Maureen Bavdek)