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Consumers and health professionals are advised that Medtronic Australasia, in consultation with the TGA, has issued a hazard alert for its Mosaic Porcine Aortic Bioprosthesis Model 305 due to the potential for implanting oversized valves.
To address the issue, Medtronic Australasia is recalling resources used to select appropriately sized devices for implantation.
The Mosaic Porcine Aortic Bioprosthesis Model 305 is an artificial valve used to replace faulty aortic heart valves. The artificial valve incorporates synthetic materials and porcine heart valve tissue.
The implantation of oversized prosthetic valves can potentially result in the valve not functioning optimally. This problem has occurred at a rate of 0.33% (3.3 reports per 1000 aortic valves).
An investigation has found that the sizing chart and associated sizing tools (known as 'obturators' or 'sizers') may have contributed to the selection of larger-than-optimal implants. Medtronic Australasia is recalling the resources and will replace them with updated versions.
The hazard alert and recall only affect the Medtronic Mosaic Porcine Aortic Bioprosthesis Model 305 (all sizes and configurations, Standard and Ultra) and its associated sizing materials. Mosaic Mitral Bioprosthesis Model 310 is not affected.
Information for consumers
If you, or someone you care for, have received a porcine aortic bioprosthesis and you are concerned about this issue, contact the treating surgeon or cardiologist for advice.
The issue is not common, affecting 0.33% of aortic implants using the Mosaic Porcine Aortic Bioprosthesis Model 305.
Information for surgeons and cardiologists
Medtronic Australasia has written to cardiologists and surgeons advising them of the issue.
Surgeons and cardiologists should continue to follow-up with their patients as per their usual practice and in accordance with published guidelines.
Medtronic Australasia has updated both the iEOA Mosaic Aortic Bioprosthesis sizing chart and Mosaic obturators/sizers. The Instructions for Use for the modified Mosaic obturators/sizers has been updated to include the new sizing chart (iEOA chart).
Surgeons are advised to begin using the new iEOA sizing chart and modified Mosaic obturators/sizers for future implantations.
A Medtronic Australasia field representative will contact surgeons about the new obturator/sizer set and sizing chart. If you have not been contacted or want to order the new materials directly, contact Medtronic Australasia on 1800 668 670.
Information for health professionals
Medtronic Australasia has written to cardiologists and surgeons advising them of the issue.
If you are treating a patient who has received a Mosaic Porcine Aortic Bioprosthesis Model 305, reassure them that it is not common (occurring at a rate of 0.33%).
Be alert to the issue in your clinical decision-making and consider referring the patient to a relevant specialist, if required.
Additional information
Implantation of substantially oversized Mosaic Porcine Aortic Bioprostheses Model 305 can potentially lead to cases of higher-than-expected transvalvular gradients. Higher-than-expected transvalvular gradients (>25 mmHg) associated with the Mosaic Procine Aortic Bioprosthesis Model 305 have occurred at a rate of 0.33% (3.3 reports per 1000 aortic implants). A subset of these valves have required explantation within five years of implantation at an overall occurrence rate of 0.1% (one explant per 1000 aortic implants).
Specifically, considerable oversizing, or implanting a valve substantially larger than the native aortic annulus, can result in the alteration of normal leaflet movement as blood flowing through the native annulus might not properly match the size and/or shape of the inflow of the Mosaic Porcine Aortic Bioprosthesis Model 305.
Reporting problems
Consumers and health professionals are encouraged to report problems with medical devices. Your report will contribute to the TGA's monitoring of these products. For more information see the TGA Incident Reporting and Investigation Scheme (IRIS).
The TGA cannot give advice about an individual's medical condition. You are strongly encouraged to talk with a health professional if you are concerned about a possible adverse event associated with a medical device.