NeoChord Inc. said Monday that it raised $4.7 million to develop a device that repairs leaky heart valves.

The Minnetonka-based start-up says its technology, created by heart surgeons at the Mayo Clinic in Rochester, can help the 250,000 new patients each year who suffer from mitral valve regurgitation, a progressive disease that can lead to cardiac arrest. Doctors now must cut open the chest and stop the heart before replacing the valve.

With NeoChord's technology, doctors make a small incision near the ribs and insert a device into the still-beating heart that helps the suspect valve open and close properly. The technique is much less expensive and complicated than risky heart surgery, investors say.

"We like to invest in products that will lower health care costs," said Jack Ahrens, founder and general partner of TGap Ventures, an early stage venture capital firm in Kalamazoo, Mich., and one of NeoChord's lead investors. "Anything that goes from invasive to minimally invasive is attractive."

The company's other investors include Mayo, Heron Capital, Clarian Health Ventures, and Twilight Ventures. NeoChord hopes to begin human clinical trials this summer.

Faulty heart valves have recently drawn attention from major medical device makers. In February, Medtronic Inc. said it will buy CoreValve Inc., Irvine, Calif., for at least $700 million, and Ventor Technologies Ltd. of Israel for $325 million. Both are developing new ways to replace heart valves.

In mitral valve regurgitation, a valve fails to close properly, causing blood to flow back into the heart. The heart then pumps harder, creating stress that can lead to cardiac arrest.

Spun out of Mayo in 2007, NeoChord makes an artificial chordae tendineae, or strip of muscle, that can "tether" the valve. "We're making sure the gate doesn't swing open too wide," explained NeoChord CEO John Seaberg.

Normally, doctors perform major surgery only when the disease gets really bad. NeoChord's challenge is to persuade cardiac surgeons to perform its procedure on less sick patients who don't necessarily exhibit symptoms, said Ross Meisner, managing partner of Dymedex Consulting in St. Paul.

A Mayo study published in 2005 in New England Journal of Medicine says as much.

"Delaying surgical correction until symptoms appear is problematic," the study said. "Hence, it has been suggested that surgery should be considered while patients are asymptomatic. This approach is supported by the high feasibility, low risk, and excellent long term results of valve repair."

Seaberg said the company would be satisfied if doctors used its technology only for severe cases of mitral valve regurgitation. But he acknowledges the market potential if doctors recommend the device to patients before their diseases get worse.

Thomas Lee • 612-673-7744