SANTA ROSA -- Direct Flow Medical, Inc. has started the first patient enrollment study in the U.S.  for its Aortic Heart Valve System that treats aortic regurgitation, which could significantly lessen the need for open-heart surgery on certain patients.

The Santa Rosa-based developer of transcatheter heart valves, founded in 2004, has developed an aortic valve with a "metal-free frame and flexible, low-profile delivery system," which differs from traditional aortic heart valve replacement that often requires highly invasive open-heart surgery.

The trial will follow 30 patients at six medical centers throughout the country:  UC, Davis Medical Center, Columbia University Medical Center in New York, Henry Ford Hospital in Detroit, the Cleveland Clinic, Washington University Hospital in St. Louis and Northwestern University Hospital in Chicago.

Boston Scientific and Edwards LifeSciences are working on similar aortic valves. So far, Edwards Lifesciences has undertaken the U.S.  Pivotal Trial and its valve is commercially available in the U.S. Boston Scientific has not yet reach the U.S. clinical trial stage,  a key step before obtaining Food and Drug Administration approval, according to Dr. Charles Davidson, a consultant for Direct Flow and clinical chief of cardiology at Northwestern.

Direct Flow has received $75 million in venture capital.

Dr. Davidson likened the advancement in aortic valves to that of heart stents, which were widely hailed when they first rolled out but evolved quickly to become drug-eluting stents that better addressed certain clinical issues. Likewise with aortic valves, Direct Flow's device helps correct some issues associated with current commercial valves and patients with aortic stenosis, he said.

"The first-generation devices were revolutionary in treating patients with severe aortic stenosis," Dr. Davidson said. "Those were really kind of groundbreaking and set the stage for a whole new treatment of patients. It's a disease not well treated with medicine. But there were certain limitations with those devices. One of them was there was significant leaking around the valve, called aortic regurgitation. And that leaking has led to an increase in death after the procedure."

Aortic stenosis is a congenital condition where the opening of the aortic valve is narrowed, which decreases blood flow from the heart to the rest of the body.

Another issue with current available valves, Dr. Davidson said, is that once implanted, they're nearly impossible to retrieve or replace.

"You basically had to leave it in the patient," Dr. Davidson said. "The next generation valves and Direct Flow really address those issues. It virtually eliminated aortic regurgitation," and related vascular and bleeding complications.

Rather than performing open-heart surgery, the Direct Flow valve is inserted via a tube through the femoral artery near the groin, Dr. Davidson said. "It's a much less invasive surgery," he said. Direct Flow has received CE Mark approval in the European Union earlier this year and has studied patients there. It found that 99 percent of patients were alive 30 days after the procedure, and only 4 percent had significant vascular complications.

The U.S. trials commenced about a week ago. Early next year, a Pivotal Trial will take place, which could bring FDA approval within a couple of years.

Principal investigators for the current trial are Murat Tuzcu, M.D., vice chairman of the Department of Cardiology at Cleveland Clinic, and Patrick McCarthy, M.D., director of the Bluhm Cardiovascular Institute and chief of cardiac surgery at Northwestern Memorial Hospital.

"After surgical aortic valve replacement, aortic regurgitation is rare. We need that same level of assurance after a transcatheter procedure, and we look forward to matching those results in this study of the Direct Flow Medical System," said Dr. McCarthy.

William O’Neill, M.D., medical director of the Center for Structural Heart Disease at Henry Ford Hospital performed the first Direct Flow Medical case in the U.S. "The team at Henry Ford Hospital is pleased to be the first in the U.S. to implant the Direct Flow Medical heart valve," said Dr. O'Neill. "A device that is repositionable and able to pass through smaller diameter blood vessels is an important advance in the next generation of transcatheter aortic valve replacement systems. This could help patients who have not been good candidates for earlier [transcatheter aortic valve replacement] devices."Direct Flow Medical investors include EDF Ventures, New Leaf Venture Partners, Spray Venture Partners, Foundation Medical Partners, VantagePoint Venture Partners, and ePlanet Venture Partners.

Direct Flow has 142 employees worldwide.