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To the Editor: In his Perspective article, Maisel (March 6 issue)¹ criticizes the response of the Food and Drug Administration (FDA) to adverse events preceding the recall of Medtronic's Sprint Fidelis implantable cardioverter–defibrillator (ICD) leads. The FDA agrees with Maisel's premise that physicians and patients should receive accurate and timely information about problems with marketed medical devices. In fact, we are increasing our efforts to issue early communications about potential problems with regulated medical products, and we have created a new Risk Communication Advisory Committee to help us do so. However, we are concerned about several statements in Maisel's article that may have misled readers.

For example, Maisel criticizes the FDA for approving changes in the Medtronic lead on the basis of bench testing rather than clinical data. FDA regulations allow manufacturers to apply for marketing of a modified device on the basis of bench testing, and many devices are approved in this way. This is not an inherently unsafe approach, as Maisel implies. In evaluating an application involving a modified device, we analyze the proposed modification, determine the potential types of failure, and tailor testing requirements accordingly. In many cases, our questions are best answered by performing appropriate engineering analyses, but in other cases, we also require clinical data.

To require that these modified devices undergo clinical trials across the board as a condition of FDA approval would limit the availability of improved products. Also, most of these trials would have insufficient power to detect small but clinically meaningful differences in performance.

Maisel also criticizes device manufacturers for continuing to market existing models while modified (and presumably improved) models await FDA approval. But there is nothing inherently wrong with doing so unless the older models pose an undue health risk. The continued marketing of Fidelis leads occurred when available data indicated that the fracture rate was similar to that of other leads. When continued monitoring of the situation showed otherwise, the lead was recalled and existing stocks were promptly called back.

Unfortunately, Maisel's article diverts attention from deeper problems. For example, how can bench testing be better designed to be predictive of clinical performance? How can postmarketing clinical registries be used more effectively as early warning systems, alerting us to low-frequency, unexpected problems with devices? And given that we cannot detect low-rate events without a steady flow of accurate information, how can physicians be persuaded to report adverse events to us promptly? We welcome thoughtful input on these issues from clinicians, patients, and the medical-device industry.

Daniel G. Schultz, M.D.
Food and Drug Administration
Rockville, MD 20850
execsec{at}fda.hhs.gov

References

1. Maisel WH. Semper fidelis -- consumer protection for patients with implanted medical devices. N Engl J Med 2008;358:985-987. [Free Full Text]

There is no "deeper" problem than the unnecessary exposure of patients to an underperforming permanently implanted medical device. Schultz outlines several important questions that must be answered in order to strengthen the device-approval and postmarketing-monitoring processes. In addition, technological advances such as remote, wireless device monitoring will, in some cases, facilitate collection of the needed performance data. More critical, however, is the need for a philosophical shift — from a medical-device industry that primarily reacts to performance failures to one that better anticipates them.

William H. Maisel, M.D., M.P.H.
Beth Israel Deaconess Medical Center
Boston, MA 02215
wmaisel{at}bidmc.harvard.edu

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