The FDA Circulatory System Devices Panel of the Medical Devices Advisory Committee voted unanimously on 19 March 2010 in favour of approval with conditions of the Revo MRI SureScan pacing system designed as MR Conditional, or safe for use in magnetic resonance imaging (MRI) systems under specified conditions. If approved, Revo MRI has the potential to be the first FDA-approved pacing system designed for use in the MRI setting.
The FDA’s Circulatory System Devices Panel recommended Revo MRI for approval with conditions related to the planned post-market study, health care professional training, and labeling to reflect MRI scans are to be conducted with the full Revo MRI SureScan Pacing System. The FDA will consider the panel’s recommendation in its review of Revo MRI; however, it is not bound by its Advisory Committee’s recommendations.
“MRI is critical in the diagnosis of many serious conditions. However, patients with current pacemakers most often do not have access to this vital technology,” said Pat Mackin, president of the Cardiac Rhythm Disease Management business and senior vice president at Medtronic. “The result of the panel’s meeting brings Medtronic one step closer to helping address an important unmet patient need. We look forward to working with the FDA during the regulatory process so that we may provide certain pacemaker patients with access to MRI scans.”
The FDA panel reviewed safety and effectiveness data from a prospective, randomised trial at 42 centres around the world featuring 464 implanted patients. Major inclusion criteria included standard class I or II dual chamber pacemaker indication, which allowed for pacemaker-dependent patients. Patients were excluded if they had previously implanted medical devices or abandoned leads. Patients were randomised at implant to either receive an MRI or not to receive an MRI.
The primary endpoints evaluated were safety and effectiveness of the Revo MRI pacing system in the MRI environment. For safety, the MRI group was evaluated for MRI procedure-related complications through one month post MRI. The primary effectiveness endpoint tested equivalence between MRI versus control for atrial and ventricular pacing capture thresholds and atrial and ventricular sensed amplitudes through one month post MRI.
Revo MRI includes hardware modifications to the device and leads that are designed to reduce or eliminate several hazards produced by the MRI environment. In addition, since MRI scanners may cause traditional pacemakers to misinterpret MRI-generated electrical noise and withhold pacing therapy or deliver unnecessary pacing therapy, this new pacemaker includes a new SureScan feature that sets the device into an appropriate mode for the MRI environment.
The device and leads also contain radiopaque markers, viewable via X-ray, to indicate that the device is MR-Conditional. MR-Conditional is a term used to indicate that a device may be used in the MRI environment under certain conditions, such as a particular type of MRI scanner and scanner settings.