We read with interest the recent case report by Reghunathan et al entitled, "Endovascular retrieval of a CardioMEMS heart failure system" that describes the nonsurgical removal of a CardioMEMS HF sensor [1]. The CardioMEMS HF device was approved for use in the United States by the Federal Drug Agency in May, 2014, following which a 1200 patient registry was initiated and completed in 2018. To date, approximately 10,000 devices have been implanted within the United States. Sensor implantation requires use of a 0.18 inch over the wire system and a 12-French sheath. The radiographic appearance of the CardioMEMS device is unique with a central body of the sensor, surrounded by 2 radio-opaque nitinol loops that maintain apposition to the adjacent pulmonary artery wall. Following sensor implant, it is assumed that endothelization of the nitinol hoops occur such that clopidogrel therapy is only required for 30 days.
Removal of "unknown" foreign bodies is problematic as sheath size required for removal and the most appropriate portion of the foreign body to snare is unknown. It is not surprising that the authors could not withdraw the device thru a 9-French sheath given that a 12-French sheath is required for placement [2]. Removal of the device, snare and sheath en-bloc may have inadvertently seeded the subcutaneous tissue with additional Candida. Although culture of the device yielded Candida, it is unclear if the device was the source of the infection or was seeded during the process of fungemia. Given that the device was removed and the patient died 5 days later suggests that the device may have not been the source of the infection. A tagged white blood cell scan may have been useful to confirm clear infection of the CardioMEMS sensor, prior to the attempted removal. Removal of the device may have also resulted in injury to the relatively thin pulmonary artery wall. Figure 4 shows tissue adherent to the nitinol loops. It would be useful to know which portion of the pulmonary artery wall were present within this tissue—intima, media, or adventia. The authors do not comment on the amount of force required for device removal—excessive force with disruption of the pulmonary artery wall could potentially lead to pulmonary artery rupture and/or perforation; which may be devastating complications. Although CardioMEMS sensor removal should not be advocated, an approach based upon knowledge of the device would involve use of a long 14- or 16-French sheath placed just proximal to the device, use of a snare to contact the proximal nitinol loop with containment of the device in a coaxial manner within the long sheath, with subsequent removal of the device within the sheath in order to reduce the possibility of device embolization through the right heart and/or contralateral pulmonary artery.
Footnotes
Conflicts of Interest: Dr. Shavelle receives research support from Abbott, Abiomed and National Institutes of Health and is a consultant for Abbott, the manufacturer of the CardioMEMS system. Dr. Jermyn receives research support from Abbott and Novartis and is a consultant for Abbott, the manufacturer of the CardioMEMS system.
Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.radcr.2019.03.005.
Appendix. Supplementary materials
References
- 1.Reghunathan A., Chick J.F.B., Gemmete J.J., Hage A., Mahn J., Khaja M.S. Endovascular retrieval of a CardioMEMS heart failure system. Radiol Case Rep. 2018;13(2):386–388. doi: 10.1016/j.radcr.2018.01.013. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Shavelle D., Jermyn R. The CardioMEMS heart failure sensor: a procedural guide for implanting physicians. J Invasive Cardiol. 2016;28(7):273–279. [PubMed] [Google Scholar]
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