Dublin-based Medtronic plc. has invested considerable resources into its renal denervation program, but the company has not completed its regulatory journey for the U.S. market just yet. Medtronic failed to persuade an FDA advisory committee of the virtues of its Symplicity Spyral device due to inconsistent results from the two major studies presented at the hearing but vowed to keep working on the application despite the sustained headwinds.