Correspondence Letter by Lederman et al Regarding Article, “MRI-Induced Stent Dislodgment Soon After Left Main Coronary Artery Stenting” To the Editor: It is important to dispute that magnetic resonance imaging caused coronary stent dislodgement in the patient described by Parthasarathy and colleagues.1 The BX Velocity stent used in the Cypher device in their report is composed of 316 L stainless steel,2 which is weakly ferromagnetic. According to the industry standard applied in its commercial development,3 a static magnetic field of 1.5T or 3.0T generates far less ferromagnetic attractive force on this specific device than does Earth gravity. This is far less than physiological forces imposed on an ostial coronary stent, such as from cardiac motion, coughing, and shear stress from flowing blood. For illustration, we suspended a 3.0×28 mm Cypher stent from a suture in a test apparatus resembling the ASTM-F2052 standard, positioned at the location of the highest spatial gradient of the static magnetic field of a 1.5T scanner (Aera, Siemens). This revealed a deflection of ≈5o. Extrapolating to an 8-mm stent, this corresponds to a ferromagnetic deflection force of 1.1 mg. More likely, the short ostial 3.5×8 mm left main coronary stent was ejected spontaneously or dislodged by the guiding catheter, guidewire, or intravascular ultrasound catheter used during implantation. The causality inferred from the temporal association of MRI and stent embolization is not plausible. Appropriately selected and tested devices are safe from ferromagnetic displacement during MRI using the rated static magnetic fields, even immediately after appropriate implantation.4

Sources of Funding This work was supported by the Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health (Z01-HL005062, R.J. Lederman).

Disclosures None. Robert J. Lederman, MD Toby Rogers, MD Anthony Z. Faranesh, PhD Cardiovascular and Pulmonary Branch Division of Intramural Research National Heart, Lung, and Blood Institute National Institutes of Health Bethesda, MD

References 1. Parthasarathy H, Saeed O, Marcuzzi D, Cheema AN. MRI-induced stent dislodgment soon after left main coronary artery stenting. Circ Cardiovasc Interv. 2013;6:e58–e59. 2. Cordis Corporation. Instructions for use: CYPHER sirolimus-eluting coronary stent. 2006. 3. ASTM International. Standard Test Method for Measurement of Magnetically Induced Displacement Force on Medical Devices in the Magnetic Resonance Environment. 2006;F2052–06. 4. Levine GN, Gomes AS, Arai AE, Bluemke DA, Flamm SD, Kanal E, Manning WJ, Martin ET, Smith JM, Wilke N, Shellock FS. Safety of magnetic resonance imaging in patients with cardiovascular devices: 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: endorsed by the American College of Cardiology Foundation, the North American Society for Cardiac Imaging, and the Society for Cardiovascular Magnetic Resonance. Circulation. 2007;116:2878–2891.

(Circ Cardiovasc Interv. 2014;7:128.) © 2014 American Heart Association, Inc. Circ Cardiovasc Interv is available at http://circinterventions.ahajournals.org

DOI: 10.1161/CIRCINTERVENTIONS.113.001044

Downloaded from http://circinterventions.ahajournals.org/ 128 at AUSTRALIA NATL UNIV on March 13, 2015

Letter by Lederman et al Regarding Article, ''MRI-Induced Stent Dislodgment Soon After Left Main Coronary Artery Stenting'' Robert J. Lederman, Toby Rogers and Anthony Z. Faranesh Circ Cardiovasc Interv. 2014;7:128 doi: 10.1161/CIRCINTERVENTIONS.113.001044 Circulation: Cardiovascular Interventions is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231 Copyright © 2014 American Heart Association, Inc. All rights reserved. Print ISSN: 1941-7640. Online ISSN: 1941-7632

The online version of this article, along with updated information and services, is located on the World Wide Web at: http://circinterventions.ahajournals.org/content/7/1/128

Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally published in Circulation: Cardiovascular Interventions can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office. Once the online version of the published article for which permission is being requested is located, click Request Permissions in the middle column of the Web page under Services. Further information about this process is available in the Permissions and Rights Question and Answer document. Reprints: Information about reprints can be found online at: http://www.lww.com/reprints Subscriptions: Information about subscribing to Circulation: Cardiovascular Interventions is online at: http://circinterventions.ahajournals.org//subscriptions/

Downloaded from http://circinterventions.ahajournals.org/ at AUSTRALIA NATL UNIV on March 13, 2015

Letter by Lederman et al regarding article, "MRI-induced stent dislodgment soon after left main coronary artery stenting".

Letter by Lederman et al regarding article, "MRI-induced stent dislodgment soon after left main coronary artery stenting". - PDF Download Free
412KB Sizes 0 Downloads 3 Views