Safe Medical Devices for Children (2006) / Chapter Skim
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6 Adequacy of Pediatric Postmarket Surveillance Studies
6 Adequacy of Pediatric Postmarket Surveillance Studies
Pages 199-228
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From page 199... ...
(Bartlett, 1985; Bartlett et al., 2000; University of Michigan, 2005) The history of ECMO, which involves a complex system of medical devices, is interesting for a number of reasons.
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From page 200... ...
When successful, innovative medical devices such as those involved in the ECMO procedure can offer dramatic cures, sustain life until another therapy is available, slow the progression of disease, or ease the distress caused by an incurable condition. Long-term and even relatively short-term exposure to a device -- and the surgical or other procedures associated with its use -- can, however, alter a child's development in complex ways.
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From page 201... ...
. Section 522 Postmarket Surveillance Studies Chapter 5 reported that FDA officials identified only two Section 522 Postmarket Surveillance studies that they had ordered in recent years following the approval or clearance of a medical device.
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From page 202... ...
. The postapproval study was to collect 5-year follow-up data on at least 180 children to assess adverse events as well as evaluate treatment outcome (reflux grade)
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From page 203... ...
For the adults implanted with the device during clinical trials, the average duration of pump support was about 3 months. The committee also learned incidentally about one voluntary postmarket study involving children.
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From page 204... ...
Conversations with FDA staff and committee review of individual device approvals indicate that clinical studies to support approval or clearance of medical devices generally last 1 to 2 years. Individual research participants may be followed for shorter periods if, for example, patients are entered into the study at different times following diagnosis.
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From page 205... ...
. FIGURE 6.1 Evolution of the Vertical Expandable Prosthetic Titanium Rib (VEPTR)
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From page 206... ...
In sum, if the narrative for an adverse event report said something like "problems with implant functioning arose after the child jumped off the sofa and bumped her head," no existing code or feasible search strategy would identify this incident as related to children's active lifestyle. Similar difficulties limit the feasibility and value of searching the database for reports that might identify adverse events related to growth and development.
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From page 207... ...
With respect to growth and development, the committee determined that locating relevant clinical studies would, by and large, require deviceby-device or condition-by-condition literature searches and device-by-device and condition-by-condition considerations of whether possibly relevant studies are "of long enough duration" to evaluate the impact of child's growth and development on the performance of an implant or to assess the effects of an implant or other medical device on the way a child grows and develops. Such a search strategy was beyond the committee's resources.
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From page 208... ...
Although specifics will vary depending on the device, premarket testing of medical devices that require clearance or approval may entail a series of evaluations that usually involve nonclinical in vitro testing (also called laboratory or bench testing) and that may extend through tests with animals, possibly cadavers, and then humans.
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From page 209... ...
Some constraints on research, however, relate less to methodological or technical challenges than to marketing or financial concerns. For example, as is true for other medical products, once a device is approved or cleared, a manufacturer may not be enthusiastic about studying additional uses or populations because such studies could provide negative information that could, in turn, lead to labeling restrictions or even market withdrawal.
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From page 210... ...
This brief review of study designs is intended to further illustrate the options and challenges of medical device studies. Appendix D discusses in more depth the objectives, characteristics, and limitations of major study designs and data analysis techniques (e.g., data mining)
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From page 211... ...
Such studies are sometimes prospective but more often retrospective, that is, based on information already existing in medical records, billing databases, or other sources. The brief overview below starts with experimental studies, not because they are commonly used for postmarket studies of medical devices but because they are considered the benchmark for valid evaluations of clinical care.
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From page 212... ...
The phenomenon of the learning curve points to another complexity of device trials. Unlike the administration of many drugs in clinical trials, the use of an implant or other device in a trial may depend on a surgical or other procedure that requires new skills or involves unusual elements that must be learned.
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From page 213... ...
If such practical clinical trials included medical devices used with children, they could help narrow the knowledge gaps that especially characterize pediatric use of many medical devices. Observational and Other Study Designs Many device studies involve observational designs, in which access to an intervention or comparison group is not under an investigator's control.
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From page 214... ...
Such findings may suggest the need for closer monitoring of certain patient characteristics or adaptations in a device or aspects of its use. Fortunately, child deaths are relatively uncommon, and many critically ill children treated with innovative medical devices survive into adulthood.
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From page 215... ...
Although FDA is supportive of other registry studies such as those organized by professional societies, the agency's primary focus is on registries associated with postmarket studies that they have required or voluntarily negotiated with manufacturers. Some registries are diagnosis-based and include information about people with a diagnosis who receive certain interventions and people with the diagnosis who do not.
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From page 216... ...
Each center contributed $2,000 to the project and donated the time of personnel to fill out the forms, and the University of Alabama at Birmingham hosted the database. The group has been able to obtain outside funding for some studies, including a study of ventricular assist devices as a bridge to transplantation, but funding for major studies is an ongoing concern.
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From page 217... ...
NIH has, in the committee's experience, only reluctantly supported registries and then primarily to encourage the orderly transition of a new technology into clinical practice. Ideally, a registry to support clinical studies would be managed by an independent third-party, but the funding for such outside management may only be forthcoming after a registry has been created and shown promise.
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From page 218... ...
The difficulties for device surveillance and epidemiology created by coding limitations is captured by the following comment by a researcher on problems encountered in determining the specific model of an ultrasound device used for many obstetrical patients, even though investigators knew when and where the procedure occurred. "We needed to contact each obstetrics office and ask a busy person to find and read to us the make and model information, [and]
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From page 219... ...
Adequacy of Reporting of Information from Device Studies Even when clinical studies of medical devices are undertaken, the reporting of key information about the study procedures and outcomes is often too limited to assess the results or the quality of the research procedures that produced them. For example, the summary information of safety and effectiveness published with approvals of PMAs is helpful, but the summaries are not easy to review and they vary in how fully and clearly they describe key aspects of the studies.
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From page 220... ...
should likewise support the development work necessary to expand the core capacity for epidemiologic research on device safety. Combined with more precise recording of device information in the patient record, these steps should reduce the barriers to needed long-term postmarket studies of medical device safety and effectiveness.
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From page 221... ...
ADEQUACY OF PEDIATRIC POSTMARKET SURVEILLANCE STUDIES 221 developmental needs and characteristics face some additional constraints (see, e.g., IOM, 2004a; FDA, 2004p)
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From page 222... ...
Nonetheless, the clinical research networks funded by the National Institute for Child Health and Human Development and other NIH units might be better utilized to support the systematic assessment of medical devices used with children. In addition, surgical and device-oriented specialties should be encouraged to place greater value on the systematic evaluation of medical devices and associated procedures used with children.
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From page 223... ...
Because pediatric issues with implants and other medical devices have
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From page 224... ...
The usefulness of additional FDA advice or discussion on pediatric questions should be systematically evaluated in a number of areas, potentially including orthopedics, craniofacial fixation devices, and material biocompatibility. Recommendation 6.1: FDA should develop additional guidance for its own staff as well as for manufacturers and investigators on the iden tification and evaluation of pediatric questions or concerns at all stages in the design and evaluation of medical devices used with children.
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From page 225... ...
FDA should also work with agencies such as the Agency for Healthcare Research and Quality and university- and industry-based methodologists to strengthen methods and tools for epidemiologic research on medical device safety. FDA and others could also benefit from more comprehensive information about registries and similar resources that would, in some fashion, track pediatric experience with medical devices.
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From page 226... ...
It can and should work cooperatively with manufacturers to find ways to collect additional, valid information on products that raise concerns about long-term outcomes. It can also encourage pediatric professional societies, academic medical centers, and clinical researchers to get more involved in postmarket device surveillance, for example, by cooperating to create well-designed registries for important medical devices (or device-relevant diagnoses)
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From page 227... ...
Recommendation 6.6: FDA should collaborate with the National Insti tutes of Health, the Agency for Healthcare Research and Quality, and other research funding agencies and interested parties to define a re search agenda and priorities for the evaluation of the short- and long term safety and effectiveness of medical devices used with growing and developing children. A conference sponsored by funding agencies would be a constructive first step in constructing a research agenda for pediatric device safety and effectiveness.
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From page 228... ...
The recommendations presented above clearly require that many, in addition to FDA, share responsibility for the development of better information about the safety and effectiveness of medical devices used with children. This theme of shared responsibility is reiterated and expanded in the next chapter.
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