BACKGROUNDER - Medtronic



BACKGROUNDER

Medtronic Revo MRI™ SureScan® Pacemaker System

The Medtronic Revo MRI™ SureScan® pacing system is the first and only MR-Conditional pacemaker system FDA approved for use in the MRI environment by the U.S. Food and Drug Administration (FDA).

MR-Conditional is a term used to indicate that a medical device may be used in the MRI under certain conditions, such as a particular type of MRI scanner and scanner settings.

New Features with Revo MRI

Revo MRI was designed with hardware modifications to the device and leads (CapSure FixTM MRI SureScan) that mitigates several hazards produced by the MRI environment. 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, when programmed before an MRI scan, sets the device into an appropriate mode for the MRI environment.

The implanted pacing system must consist solely of a Revo MRI SureScan device and two CapSureFix MRI™ SureScal Model 5086MRI leads. These new leads are modified versions of the active-fixation Medtronic CapSureFix® Novus leads. Leads are insulated wires that carry precisely timed electrical impulses from the pacemaker in the patient’s chest to a specific point on the inner heart wall.

MRI Overview and Facts

MRI scans allow physicians to make a wide range of health diagnoses by viewing highly detailed images of internal organs, blood vessels, muscle, joints, tumors, areas of infection and more. The number of MRI scans performed increases each year[i], as does the number of people with implanted cardiac devices. [ii] MRI procedures are currently not recommended in the U.S. for patients who have implanted pacemakers.

▪ Approximately 60 million MRI procedures are performed worldwide each year.[iii]

▪ In 2007, there were approximately 30 million MRI scans performed in the U.S., and its use continues to grow.[iv]

▪ Each year, approximately 320,000 people in the U.S. are implanted with a pacemaker.[v]

▪ MRI procedures are indicated for 17 percent of pacemaker patients within 12 months of device implant.[vi]

▪ It has been estimated that there is a 50 to 75 percent probability that cardiac device patients will be indicated for an MRI over the lifetime of their devices.[vii]

▪ An estimated 200,000 patients in the U.S. annually have to forego an MRI scan because they have a pacemaker.[viii]

About the MR Classification System

The American Society for Testing and Materials (ASTM) is an international standards organization that has developed a classification system for implanted and ancillary clinical devices:

▪ MR Safe: An item that poses no known hazards in all MR environments. (This would be something that contains no metal or any other type of electrical conducting surface.)

▪ MR Conditional: An item that has been demonstrated to pose no known hazards in a specific MR environment with specific conditions of use. (Revo MRI)

▪ MR Unsafe: An item that is known to pose hazards in all MR environments.

Revo MRI Clinical Trial

Following several years of studying the risks for pacemaker use in the MRI environment and preclinical testing of the pacing system, Medtronic initiated its clinical trial in February 2007. This confirmatory clinical trial of MRI use for pacemaker patients was conducted at 42 centers in the United States, Canada, Europe and the Middle East; 464 patients were implanted with a complete pacing system.

The clinical trial was a prospective, randomized, controlled, un-blinded, multi-center investigational trial. Randomization of subjects to control and MRI groups was used to provide treatment effect information.

The primary endpoints included:

▪ Safety: to assess the one month post-scan MRI-related complications.

▪ Effectiveness: to compare the changes in 1) atrial and 2) ventricular pacing capture thresholds before and one month after MRI measured at 0.5ms between the MRI and control groups.

▪ Effectiveness: to compare the changes in 1) atrial and 2) ventricular sensed amplitudes before and one month after MRI between MRI and control groups

The results of the confirmatory clinical study showed that all primary safety and effectiveness endpoints were met. Overall, there was no difference in performance between the MRI group and the control group.

###

-----------------------

[i] IMV, “Benchmark Report: MRI 2007,” IMV Medical Information Division. Des Plaines, IL. 2008.

[ii] Zhan C, Baine WB, Sedrakyan , A, et al. Cardiac device implantation in the United States from 1997

through 2004: A population-based analysis. J Gen Intern Med 2008; 23(Suppl 1): 13–19.

[iii] Sutton R, Kanal E, Wilkoff BL, Bello D, et al. Safety of magnetic resonance imaging of patients with a new Medtronic EnRhythm MRI SureScan pacing system: clinical study design. Trials 2008, 9:68

[iv] IMV, “Benchmark Report: MRI 2007,” IMV Medical Information Division. Des Plaines, IL. 2008.

[v] Zhan C, Baine WB, Sedrakyan , A, et al. Cardiac device implantation in the United States from 1997

through 2004: A population-based analysis. J Gen Intern Med 2008; 23(Suppl 1): 13–19.

[vi] Sommer T, Naehle CP, Yang A, Zeijlemaker V, et al. Strategy for safe performance of extrathoracic magnetic resonance imaging at 1.5 Tesla in the presence of cardiac pacemakers in non–pacemaker-dependent patients: A prospective study with 115 examinations. Circulation, Sep 2006; 114: 1285 - 1292.

[vii] Kalin R and Stanton MS. Current clinical issues for MRI scanning of pacemaker and defibrillator patients. PACE 2005;28:326-328.

[viii] Medtronic calculations cited in Rod Gimbel and Ted McKenna, “Safety of Implantable Pacemakers and Cardioverter Defibrillators in the Magnetic Resonance Imaging Environment,” Business Briefing: Long-Term Healthcare 2005 (2005) available at .

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download