Page 193 - Safety Risk Management for Medical Devices

172 Safety Risk Management for Medical Devices

Comparison of the risk of a medical device with the state-of-the-art is another
way to establish acceptable risk. State-of-the-art in the context of ISO 14971 [3] is
defined as “what is currently and generally accepted as good practice” [3,7]. “State-
of-the-art does not necessarily mean the most technologically advanced solution”
[3,7]. If it can be shown that for the same benefit, the risk of a medical device is
less than or equal to the state-of-the-art, then it follows that the risk of the medical
device is acceptable. Conversely, if you can show that for the same level of risk,
your product delivers more benefit, you could argue that the risk of the medical
device is acceptable.
How to determine state-of-the-art—One way is to review the literature to find
applicable published scientific papers on the same or similar devices. Sound inclusion
and exclusion criteria are very important as they may be subjected to scrutiny at a
later date.
If the medical device is a new iteration of an existing approved device that is
produced by the same manufacturer, evaluation of the relevant field data in the
manufacturer’s files could be another means of collecting data on state-of-the-art.
It should be noted that “good practice” in the definition of state-of-the-art does
not limit the scope to medical devices. If, e.g., a pharmaceutical option is the
currently and generally accepted best treatment for a disease, then the risk of that
pharmaceutical option sets the bar against which to compare the risks of a medical
device that provides a therapeutic option for the same disease.
The BXM method uses quantitative methods for risk evaluation. As such, the risk
acceptability criteria also need to be quantitative. State-of-the-art risk for each Harm
severity class is defined as the level of risk that the public accepts for therapy by com-
parable medical devices. For example, let’s say a comparable medical device which has
been in the market for some time, has a reported history of five cases of permanent,
life-threatening injury to patients on a base of 10,000 patient-years of use. Since the
predicate device is approved and continues to be marketed as a sufficiently safe device,
the risk level of 0.05% per patient-year can be construed as an acceptable risk limit
for the severity class of Critical, for that type of device/therapy.
In some cases, such as when a new and novel device is produced, or when a
significant iteration on an existing device is made to deliver novel new therapies,
state-of-the-art data may not be available. In such cases, risk acceptance criteria are
derived from evaluating clinical study data, and formal benefit risk analyses.
See Chapter 23, Benefit Risk Analysis, for more information on how to perform a
benefit risk analysis. It is noteworthy to realize that in such novel situations, the
device under analysis could establish the state-of-the-art.
Stakeholder concerns—“It is well established that the perception of risk often differs
from empirically determined risk estimates. Therefore the perception of risk from a
wide cross section of stakeholders should be taken into account when deciding what