For devices in which the ferromagnetism of the device is a significant safety concern, consideration should be given to performing the study at the lowest field strength available to reduce whatever ferromagnetic risk might be present. Most embolization coils that have been tested have been labeled as “MR safe”; the remainder that have been tested have been labeled as “MR conditional.”1 Patients who have been treated with nonferromagnetic embolization coils can undergo MR examination any time after coil implantation. For cases for which there is a clear potential clinical benefit of scanning in the days to weeks after implantation, the benefits of the MR examination will likely outweigh the risks of the examination, and MR examination should generally be performed. 2017-08-16T13:11:22Z Because of the increasing use of MR examinations, as well as the increasing number of cardiovascular devices implanted in patients, efforts by industry, working in collaboration with academia, to manufacture devices, including pacemakers and ICDs, that are specifically designed to be safe for MR examination should be continued and intensified. <> These properties of nitinol allowthe Watchman device to configure to the contours of theLAA after deployment. Therefore, particularly in cases in which there is a relative contraindication to device examination and the examination location is distinct from the device location, consultation with a person with expertise in MR physics and MR safety is recommended. 1) Confirm MRI Readiness. Fractured leads may pose a particularly high risk of thermal injury. The pacemaker/ICD should be interrogated before and after the procedure. The reader should be aware that local artifact remains an issue for many stents. In 1997, the Food and Drug Administration (FDA), Center for Devices and Radiological Health, proposed definitions for the terms “MR safe” and “MR compatible” (Table 1).25 With this terminology, MR testing of an implant or object for MR safety involved assessments of magnetic field interactions, heating, and, in some cases, induced electrical currents, whereas MR compatibility testing required all of these plus characterization of artifacts. Tr… Since its FDA approval in March 2015, the Watchman™ left atrial appendage closure device has been implanted into nearly 50,000 patients with nonvalvular atrial fibrillation (AF) as a … Inpatients should be examined for the presence of temporary devices (eg, pulmonary artery catheters or temporary pacing leads). The 9526 Reveal Plus insertable loop recorder (ILR; Medtronic) is a single-use, subcutaneously implanted programmable device that contains 2 surface electrodes used to continuously record the patient’s electrocardiogram. The implant is designed to prevent blood clots caused by atrial fibrillation (A-fib) from getting into the bloodstream. Therefore, it is unlikely that such implants would become moved or dislodged as a result of exposure to static magnetic fields of MR systems operating at up to 1.5 T. Studies of MR examination of both animals and humans with implanted IVC filters have thus far not reported complications or symptomatic filter displacement.63–68 Several animal studies have even used “real-time” MR for the placement of IVC filters.69,70, Most IVC filters that have been tested have been labeled as “MR safe”; the remainder of IVC filters that have been tested are classified as “MR conditional.”1 Patients who have been treated with nonferromagnetic IVC filters can undergo MR examination any time after filter implantation. <> The Watchman device will be pushed through the catheter into your left atrial appendage where it will self-expand into a parachute shape with a cap. In addition, a more general discussion of safety issues is also provided that uses the expertise of the writing group to synthesize the FDA labeling using the American Society for Testing and Materials terminology with the latest experimental and clinical data, as well as expert consensus opinion, to give guidance to as broad a target audience as possible for issues regarding MR safety and cardiovascular devices. In addition, it may have been necessary to evaluate the functional or operational aspects of an implant or device relative to specific MR imaging conditions. The device … Customer Service For cases in which there is a clear potential clinical benefit of scanning in the days to weeks after implantation, the benefits of the MR examination will likely outweigh the risks of the examination, and MR examination should generally be performed. <>stream It’s a parachute-shaped device that expands to the size of a quarter when implanted. The WATCHMAN and WATCHMAN FLX Devices are permanent implants designed to close the left atrial appendage in the heart in an effort to reduce the risk of stroke. Your heart may be punctured during the procedure. If the specific identity of a device cannot be confirmed, but it is believed for clinical reasons that the scan should be performed at that time, consideration should be given to performing the study at the lowest field strength available to reduce whatever ferromagnetic risk might be present. What MRI safety information does the labeling contain? Cardiac closure and left atrial appendage occluder devices are typically made from metals that include nitinol, titanium, titanium alloy, MP35N, 316L stainless steel, and 304V stainless steel. endstream Table 1. The Watchman device will be pushed through the catheter into your left atrial appendage where it will self-expand into a parachute shape with a cap. The majority of prosthetic heart valves and annuloplasty rings that have been tested have been labeled as “MR safe”; the remainder of heart valves and rings that have been tested have been labeled as “MR conditional.”1 On the basis of the above studies and findings, the presence of a prosthetic heart valve or annuloplasty ring that has been formally evaluated for MR safety should not be considered a contraindication to an MR examination at 3 T or less (and possibly even 4.7 T in some cases) any time after implantation. The device is made of nitinol (NiTi), an alloy of … endobj In patients who have been treated with a weakly ferromagnetic IVC filter (Gianturco bird nest IVC filter [Cook], stainless steel Greenfield vena cava filter [Boston Scientific]), it is advised that the patient wait at least 6 weeks before undergoing an MR examination (because these older devices initially may not be anchored as firmly in place as other devices discussed in the present report), unless there is a strong clinical indication to perform the MR examination sooner after implantation, and as long as there is no reason to suspect that the device is not positioned properly or that it is not firmly in place. Recommendations It is recommended that patients register the conditions under which the implant can safely be scanned with the MedicAlert Foundation (www.medicalert.org) or an equivalent organization. There remains confusion and controversy regarding which patients with cardiovascular devices can safely undergo MR examination. Given the risks associated with MR imaging of certain cardiovascular (as well as other) implants and devices, thorough and effective screening procedures for patients who are to undergo MR examinations are essential.3,17,24 Indeed, most MR examination adverse events are believed to be due to deficiencies in screening methods.3 Therefore, all patients should undergo a thorough screening procedure for cardiovascular and other implants and devices, including an interview with a healthcare worker specifically trained in MR safety and completion of a standardized screening form, which should then be thoroughly reviewed by the MR technologist or physician. Most coronary artery and peripheral vascular stents are composed of either 316L stainless steel or nitinol. Furthermore, many of the reported cases of MR-related injuries and most of the few fatalities that have occurred have been the result of failure to follow established safety guidelines or the use of outdated information related to the safety aspects of biomedical implants and devices. “This nonrandomized, nonadjudicated series of nearly 4000 US patients implanted with the Watchman device, included as its primary end point safety data reported by device representatives … Although 1 study discussed above found that ICDs manufactured after 2000 may be more resistant to changes in function during MR examination, this finding should not be taken as a “green light” to routinely scan patients with such ICDs. Although temporary transvenous lead heating might be minimized or avoided by scanning anatomic regions above (eg, head/brain) or below (eg, lower extremities) cardiac pacing leads, scanning of patients with temporary transvenous pacing leads (without the generator) is not recommended. For more on AHA statements and guidelines development, visit http://www.americanheart.org/presenter.jhtml?identifier=3023366. Although the gradients are much weaker than the main magnetic field, the gradients are repeatedly and rapidly turned on and off. <> Although there is a theoretical possibility of an electromagnetic interaction with a heart valve that contains metal in the disk or leaflet that could inhibit opening and closing of the mechanical heart valve prosthesis (referred to as the Lenz effect), this has never been demonstrated experimentally or reported clinically.56 Those valves and rings that have undergone testing thus far at 3 T have not demonstrated clinically significant magnetic field interaction or MR-related heating and thus have been found to be safe for clinical MR examinations.3,43. Acrobat Distiller 10.1.16 (Windows) Implantation of the stent against the vessel wall provides for immediate anchoring of the stent. However, sufficient data are not available to demonstrate MRI safety and there may be potential risks (eg, device migration, vessel damage) that could be associated with force applied to the metallic components of the Zenith AAA Endovascular Graft. Hemodynamic support devices, including intra-aortic balloon pumps, right ventricular assist devices, and left ventricular assist devices, are complex devices with variable degrees of ferromagnetic materials, moving parts, and electrical components. Instruct the patient to alert the MR system operator to any unusual sensations or problems. For the purposes of this statement, the term “ferromagnetic” is used to denote a substance that experiences an attractive force in the presence of a magnetic field. For cases in which there is a clear potential clinical benefit of scanning in the days to weeks after implantation, the benefits of the MR examination will likely outweigh the risks of the examination, and MR examination should generally be performed. The labeling approved by the FDA using the latest American Society for Testing and Materials International designation is given for each device type discussed that has been labeled with this newer terminology. Do not scan a patient without first programming the MRI … If such scanning is performed, the risks of MR scanning should be discussed specifically and clearly with the patient, and the written informed consent should specifically list risks, including (1) pacemaker/ICD dysfunction, (2) pacemaker/ICD damage, (3) arrhythmia, and (4) death. Patients who have a pacemaker or ICD should not undergo an MR study if an alternative diagnostic test is available, and MR imaging should only be considered in cases in which the potential benefit to the patient clearly outweighs the risks to the patient. endobj Watchman in the Real World: Reports on Use in High-Risk Patients and Overall Safety. The stronger the static magnetic field, the greater the magnitude of these observed perturbations. endobj This site uses cookies. Terminology applied to implants and devices relative to the MR environment has evolved over the years. “The Watchman device, which has been implanted in more than 90,000 patients globally, continues to demonstrate a reduced risk of stroke and has shown reduced bleeding post-procedure … The device has a mesh membrane that acts as a filter at the opening of the LAA to prevent blood clots from entering the bloodstream. Platinum coils, in contrast, create less local artifact, and some (but not necessarily all) do not significantly affect the quality of diagnostic information.3,18,72–75. Although patients with the Endologix AAA or Lifepath AAA stents may undergo MR imaging, because of the artifacts created by these stents, MR examination is not recommended as the modality of choice for examinations specifically targeted toward evaluation of the stent grafts. A second vote, on whether the product is effective in preventing clot … Introduction: The Watchman device for left atrial appendage occlusion (LAAO) has proven to be effective for stroke prophylaxis in atrial fibrillation patients. As a result of ferromagnetic interactions, a device may be moved, rotated, dislodged, or accelerated toward the magnet. One ex vivo study of temporary transvenous pacing leads reported temperature increases of up to 63.1°C.82 Preliminary results of a recent study confirmed that even unconnected temporary transvenous pacing (as well as permanent pacing) leads can undergo high temperature increases at 1.5 T.83 In a chronic-pacemaker animal model undergoing MR examination at 1.5 T, temperature increases of up to 20°C were measured, although pathological and histological examination did not demonstrate heat-induced damage of the myocardium.84 The MR imaging conditions that generated such elevated lead temperatures included use of the body RF coil to transmit RF energy over the area of the lead (eg, an MR examination of the chest/thorax). The degree of in-stent stenosis cannot be assessed reliably in the case of coronary stents or peripheral stents, although patency of the peripheral stent can usually be inferred from a complete assessment of the MR examination. For weakly ferromagnetic devices for which there are not currently enough data and consensus to make the recommendation that scanning can be performed safely any time after implantation, the writing group recommends that the physician weigh the risks and benefits of scanning patients with such devices on a case-by-case basis and adopt the following approach: For cases that occur in the days to weeks after device implantation in which there is a clear potential clinical benefit of scanning the patient at that time (eg, acute back pain and lower-extremity weakness after trauma), the benefits of the MR examination will likely outweigh any risks of the examination, and MR examination should generally be performed. The WATCHMAN and WATCHMAN FLX Devices are permanent implants designed to close the left atrial appendage in the heart in an effort to reduce the risk of stroke. This table represents the relationships of writing group members that may be perceived as actual or reasonably perceived conflicts of interest as reported on the Disclosure Questionnaire, which all members of the writing group are required to complete and submit. Patients with retained temporary epicardial pacing wires are believed to be able to safely undergo MR procedures, and patients do not need to be routinely screened for the presence of such wires before scanning. For cases in which there is a clear potential clinical benefit of scanning in the days to weeks after implantation, the benefits of the MR examination will likely outweigh the risks of the examination, and MR examination should generally be performed. “This nonrandomized, nonadjudicated series of nearly 4000 US patients implanted with the Watchman device, included as its primary end point safety data reported by device representatives … Team approach to reducing atrial fibrillation-related … WATCHMAN is “MRI conditional,” which means you can safely have … The Watchman LAA closure device has a self-expanding nitinol cage with a permeable polyester fabric on the surface and fixation barbs surrounding the perimeter. 3e3e17480e6a94efad2b4f46258ee8eb6ddb8512 The Watchman is inserted during an outpatient procedure through a catheter in your groin that is then fed up into your heart. To purchase additional reprints, call 843-216-2533 or e-mail [email protected]. The American Heart Association makes every effort to avoid any actual or potential conflicts of interest that may arise as a result of an outside relationship or a personal, professional, or business interest of a member of the writing panel. Advances in MR imaging over the last 2 decades have led to MR becoming an increasingly attractive imaging modality, one that provides excellent spatial resolution and multiplanar 3-dimensional analysis while not exposing patients to the risks associated with computerized tomography and invasive procedures. You may have an air embolism (air or bubbles block a blood vessel). It’s a parachute-shaped device that expands to the size of a quarter when implanted. A sterile, disk-like, device used for the non-surgical closure of cardiac defects. The issue of when patients who have been treated with weakly ferromagnetic devices may undergo MR examination has not been established definitively for every device and thus remains controversial. Many heart valve prostheses and annuloplasty rings have been evaluated to determine whether they are acceptable for patients undergoing MR examinations with scanners operating at 1.5 T or less.3,43,48,49,51 Of these, several displayed measurable yet relatively minor magnetic field interactions in relation to the static magnetic fields of the MR systems used for testing. Therefore, a careful assessment of these potential risks and the potential benefits to the patient should be completed before use of MR imaging.”46 The writing group agrees with this approach. The timing of MR examination at 3 T or less in patients with embolization coils that are weakly ferromagnetic should be weighed on a case-by-case basis. The device, when used in the MR environment, has been demonstrated to present no additional risk to the patient or other individual but may affect the quality of the diagnostic information. No matter what treatment pathways you and your team decide to follow, the conversations you have together now and in the future are essential for protecting your health and ensuring you are feeling well and able to enjoy your life. The writing committee emphasizes that efforts by industry to manufacture pacemakers and ICDs that are specifically designed to be acceptable for patients undergoing MR procedures should be intensified, an approach preferable to the current “ad hoc” methods described above. Like many other devices … At the end of the day, the panel voted unanimously that the Watchman device was safe for the indicated patient group. Therefore, for specific guidelines for specific devices, particularly when there is doubt as to the safety of scanning a patient with a given device, the reader is encouraged to refer to a more detailed source of safety information, such as dedicated Web sites,1,2 reference manuals,3 or, when available, the manufacturer’s product information. Team approach to reducing atrial fibrillation-related … Safety Topic / Subject Watchman Left Atrial Appendage Closure Device Atritech Inc. and Boston Scientific, www.bostonscientific.com . MR imaging has thus developed into a broadly applied diagnostic tool for patients with cardiovascular and other disease states, and the number of patients undergoing scanning each year is increasing. Advances in magnetic resonance (MR) imaging and MR angiography over the last 2 decades have led to MR becoming an increasingly attractive imaging modality. Those pacemakers that have been tested have been labeled as “MR unsafe.”1 At present, MR examination of non–pacemaker-dependent patients is discouraged and should only be considered in cases in which there is a strong clinical indication, in which the benefits clearly outweigh the risks, and then according to the criteria listed in the text and Table 2. Important Safety Information. Recommendations regarding the scanning of patients with permanent pacemakers and ICDs can be expected to evolve over time as more studies become available. An American Heart Association Scientific Statement From the Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology, and the Council on Cardiovascular Radiology and Intervention: © American Heart Association, Inc. All rights reserved. 32 0 obj Most coronary and peripheral vascular stents that have been tested have been labeled as “MR safe”; the remainder have been labeled as “MR conditional.”1 Tested coronary artery stents (including tested drug-eluting coronary stents) that are nonferromagnetic (all currently used coronary stents) can be safely scanned at 3 T or less any time after implantation. Regarding the safety of MR imaging in patients with sternal wires is generally to... 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