NEW ORLEANS, April 3: A new type of heart valve replacement using a bioprosthetic implant made of cow tissue showed similar survival rates as open heart surgery and extended life expectancy, US researchers said on Sunday.

The new catheter-inserting technique is less invasive than conventional surgery and may be a promising option for severely ill patients, but also carries greater risk of stroke and other heart complications. The method lowered costs involved with re-hospitalisation in frail, elderly patients and was found to increase life expectancy by as much as 1.9 years, said the research presented at the American College of Cardiology conference.

The study compared results among 699 patients with a median age of 84, who were assigned to either transcatheter aortic valve replacement or open heart surgery to replace the aortic valve.

All the patients suffered from severe aortic stenosis, a clogged valve that impedes the pathway of oxygen-rich blood by making the heart work harder to pump blood through a narrowing opening.

The condition affects nine per cent of Americans over 65. Without treatment, up to half of patients die within two years.

The TAVR process involves taking a wire mesh stent that holds three stitched-in valve flaps made of cow tissue, and inserting that into the heart via a catheter in a leg artery or under the rib cage. The bioprosthetic, called the Edwards SAPIEN heart valve, is made by Edwards Lifesciences in California.—AFP