The FDA has allowed Medtronic to modify its CoreValve U.S. pivotal clinical trial. The revised trial will assess the CoreValve system in inoperable patients in a single-arm study with a primary endpoint of all-cause death or major stroke within 12 months. The revision also will evaluate alternate implantation routes for delivering transcatheter valves, such as the subclavian approach.

The Medtronic CoreValve U.S. trial includes two studies in different patient populations: one study of patients diagnosed as high risk for aortic valve surgery, and a second study of patients diagnosed as extreme risk. In the revised trial design, patients deemed at extreme risk will not be randomized to optimal medical management, where outcomes for these patients have been shown to be significantly worse than those treated with transcatheter valves, according to the company. Rather, this patient group will be evaluated against a performance goal derived from contemporary studies.

As previously planned, patients in the high-risk group still will be randomized one-to-one to either transcatheter aortic valve implantation with CoreValve or to surgical aortic valve replacement.

Also, Medtronic said the modified trial will now include the assessment of alternative implantation routes, including the subclavian approach, in both patient populations.

“For some patients, transfemoral access simply is not feasible due to vessel size or impairment,” said David H. Adams, MD, chair of the cardiothoracic surgery department at the Mount Sinai Medical Center and co-principal investigator of the CoreValve U.S. clinical trial.

The first implants in the Medtronic CoreValve trial occurred in December 2010. Overall, the trial will seek to enroll more than 1,300 patients at 40 U.S. clinical sites.