WASHINGTON Medtronic Plc's non-invasive transcatheter aortic valve replacement (TAVR) system proved as safe as traditional surgery in intermediate-risk patients in a two-year study presented on Friday, paving the way for its use in a wider patient population.
Medtronic's TAVR systems succeeded in demonstrating non-inferiority with no statistically significant difference in a combination of all-cause mortality and disabling stroke. The rate was 12.6 percent for TAVR and 14 percent for surgical valve replacement.
For death rates alone, the two procedures were virtually identical at 11.4 percent for TAVR and 11.6 percent for surgery.
For disabling stroke the difference was more pronounced at 2.6 percent for TAVR and 4.5 percent for surgery, which researchers said just missed statistical significance.
"These are excellent, outstanding results," said Dr. Michael Reardon, the study's co-primary investigator who presented the results at the American College of Cardiology scientific meeting in Washington.
TAVR systems, which spare patients open heart surgery to replace a diseased aortic valve, are considered among the most important growth drivers for Medtronic and rival Edwards Lifesciences Corp. Both companies have U.S. approvals for use in patients deemed too frail or at high-risk from surgery.
Edwards also has U.S. approval in intermediate-risk patients, or those seen as having 3-15 percent chance of not surviving surgery. Allowing TAVR use in larger groups of patients is considered critical to sales growth.
In the more than 1,600-patient trial, 84 percent of the TAVR patients received Medtronic's CoreValve system and 16 percent the smaller second generation Evolut.
"I believe this will lead to rapid approval by the FDA for CoreValve and Evolut in intermediate-risk patients," said Reardon, professor of cardiothorasic surgery at the Houston Methodist Debakey Heart and Vascular center.
He said clinical guidelines should be changed to allow TAVR use for more patients.
In a previous trial in high-risk patients, CoreValve proved superior to surgery rather than simply non-inferior.
Reardon said that did not happen this time primarily because of how well the surgery patients fared.
"This was the lowest surgical mortality we've seen in a randomized trial," he explained. "And TAVR did just as well."
In the first 30 days, patients treated with TAVR experienced lower rates of stroke, of new atrial fibrillation, less acute kidney injury, fewer transfusions and reported improved quality of life, researchers found.
"We found exceedingly low mortality at one and two years, which should give us great confidence as we move into lower risk (patients)," Reardon said.
(Reporting by Bill Berkrot; Editing by Chizu Nomiyama)