* Sapien XT, Sapien show similar death, stroke rates at 1 yr * Fewer complications seen with newer XT model after 30 days By Bill Berkrot SAN FRANCISCO, March 10 (Reuters) - A smaller, redesigned version of Edwards Lifesciences' non-invasive heart valve replacement system called Sapien XT performed well and led to fewer complications than the original Sapien, according to data from a clinical trial presented on Sunday. Both versions, known as transcatheter aortic valve replacements (TAVR), allow surgeons to replace diseased heart valves by threading the new valve into place through an artery via a catheter, sparing patients chest cracking, open heart surgery. The XT has been available in Europe since 2010, while only the more cumbersome version, which the company and physicians consider to be obsolete, is still being used in the United States as Edwards compiles data it will use to seek U.S. approval for the new model. "With the new device, we can treat patients who have smaller vessels with less injury and less trauma and the valve positioning is more precise," said Dr. Martin Leon, a co-lead researcher of the study of 560 patients deemed too frail to endure open heart surgery. The study, which was presented at the American College of Cardiology scientific meeting in San Francisco, was designed to show that the XT is non-inferior, or at least as safe and effective, as the older version. The study's primary goal looked at a combination of death, stroke and need to be readmitted to a hospital after one year, and the results were nearly identical for the two systems, researchers said. The death rate at one year was 22.5 percent for the Sapien XT and 23.7 percent for Sapien. After one year, 5.9 percent of those who got the newer model had suffered a stroke compared with 5.7 percent for the old version. Vascular complications were reduced by 40 percent with the newer model, researchers found. Because there had been concerns about complications, especially strokes, closer to the time of the procedure with the original Sapien trials, researchers provided detailed 30-day results and were encouraged by what they found. "All the things you expect from a smaller device were born out here," Leon said. At 30 days after implantation the rate of death for any cause was 3.5 percent for Sapien XT compared with 5.1 percent for the original device. While the result favored the XT, the difference was not deemed to be statistically significant. "It's about the lowest 30-day mortality I have ever seen in TAVR and it happens to be in the sickest of the sick patients, so even though it's not statistically significant, directionally it's encouraging," Leon, director of the Center for Interventional Vascular Therapy at Columbia University Medical Center in New York, said in an interview. Patients in the study had a mean age of 84, had severe aortic valve disease and more than 96 percent suffered from moderate to severe heart failure. "I think these results are superb," said Dr. Gary Mintz, chief medical officer of the New York-based Cardiovascular Research Foundation, who was not involved in the study. "It's fundamentally a better, easier device to use," he said of the XT. Strokes at 30 days was low and nearly identical at 3.2 percent for Sapien XT and 3 percent for the original Sapien, which was also much lower than in prior Sapien trials. "We frankly didn't expect that there would be an important difference in stroke. What is encouraging is when you compare it to the Partner 1 study the stroke rates are almost half in both arms, so stroke rates seem to be going down," Leon said, referring to an earlier Sapien trial. There was a statistically significant reduction in major valvular complications, including vessel perforations and dissections, at 9.5 percent for XT and 15.2 percent with Sapien. There was also a statistically significant reduction in anesthesia time as patients spent less time on the operating table if they were getting the smaller device. Other measures also favored the new model. With Sapien there were 10 cases in which a second valve had to be implanted compared with three for the XT, and there were eight aborted procedures with Sapien versus two with XT. "We are very pleased to see improved outcomes in both the Sapien and Sapien XT patients, as compared to results from earlier trials," Larry Wood, head of transcatheter heart valves for Edwards, said in a statement. "The Sapien XT valve was designed to reduce complications of the TAVR procedure, and we believe this has been demonstrated by today's results." The transcatheter valves are widely considered to be Edwards' most important product line. The market for transcatheter aortic valve replacements is expected to reach $2 billion by 2016, according to BMO Capital Markets analyst Joanne Wuensch, and that will almost surely grow with the aging of the enormous baby boom population. In the fourth quarter, Edwards reported transcatheter heart valve sales rose 73 percent to $161 million.