A Risk-Characterization Framework for Decision-Making at the Food and Drug Administration (2011) / Chapter Skim
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5 Case Study of a Strategic-Investment Decision
5 Case Study of a Strategic-Investment Decision
Pages 92-110
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From page 92... ...
The case study simply provides an illustration of how the committee's framework might be used for a strategicinvestment decision. FRAMING THE ISSUE: MEDICAL DEVICES AND POSTMARKET SURVEILLANCE The FDA Center for Devices and Radiological Health regulates an estimated 220,000 devices, reviews around 3,500-4,000 new products each year, and monitors some 1,000 product recalls each year.
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From page 93... ...
: INTERMACS® (Interagency Registry for Mechanically Assisted Circulatory Support) is a national registry for patients who are receiving mechanical circulatory-support device therapy to treat advanced heart failure.
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From page 94... ...
. The strategic-investment decision considered here is whether FDA keeps the reporting system as it is or invests in enhanced postmarket surveillance of two specific medical devices -- artificial knees and VADs.
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From page 95... ...
Artificial Knees Artificial knees provide increased mobility and decreased pain and are generally implanted in adult patients with relatively good health. The mortality risk due to the knee replacement is primarily in the 90-day postoperative period.
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From page 96... ...
(1,000-5,000) Populations of concern Most of the exposed population are elderly; women The exposed population consists entirely of are twice as likely as men to receive implants; other people with advanced heart failure; men are 4 populations with higher than average exposure are times as likely as women to require the implants people suffering from arthritis Mortality Number of deaths per year 6,000 Reduce the uncertainty 300 Reduce the uncertainty (3,000-150,000)
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From page 97... ...
For risks associated with living 5-10% of problems 10-20% of problems Less than 5% of patients have the ability to with the implants with implanted with implanted control or reduce the risks associated with an artificial knees can be artificial knees can be implanted VAD after surgery reduced or managed reduced or managed through personal through personal action by patients action by patients Ability to Ability of informed institution to 10-25% of adverse 25-75% of adverse About 90% of adverse effects caused by VADs detect adverse detect population-level effects health effects caused health effects caused would be detected and correctly attributed health effects associated with product being by artificial knees by artificial knees evaluated could be detected and could be detected and successfully attributed successfully attributed Ability to Probability that an informed 80% 90% 80% 90% mitigate adverse institution will be able to reduce health effects or mitigate any adverse health effects associated with the specific product being evaluated if such a problem is known to exist a If the sole VAD on the market is recalled, there would be no more implants.
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From page 98... ...
The committee assumed that artificial knees are in use for about 20 years and that some patients die of causes unrelated to the implants and some require revisions. The committee made a direct judgment that the number of people receiving or living with one or two artificial knees in a given year is about 5 million but could range from 2 million to 8 million.
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From page 99... ...
There are a variety of mortality estimates in the literature (see Table 5-2 for selected values) , from which the committee estimated 0.5% 90-day postoperative mortality rate.
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From page 100... ...
The high estimate accounts for the fact that a large exposed population of 5 million who live with the devices presents the potential for a large number of people to die from some sort of implant-related complications. Potential severe adverse effects of artificial knees include the perioperative risk of serious complications and the potential for adverse effects after implantation that may lead to the need for surgical intervention, such as patellofemoral complications, arterial thrombosis, and loosening.
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From page 101... ...
Because artificial knees have been in use for many years, much of the potential improvement in patient selection and monitoring may have already been attained, so the committee estimated negligible change in the number of adverse effects that would occur because of the added surveillance of the implants, at least in the short term. Personal Controllability The primary methods by which people can eliminate or reduce their own personal risk of death or serious 90-day postoperative adverse effects are by declining to have the knee replacement and by careful selection of hospitals and
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From page 102... ...
Ability to Detect Adverse Health Effects Artificial knees that have been implanted more than a few years are examined when a patient chooses to return to an orthopedist; examinations are recommended every 2-3 years. However, the patient may not detect some problems or might not see an orthopedist about a possible problem even if walking becomes more difficult.
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From page 103... ...
Ventricular Assist Devices VADs are medical devices implanted in patients who have advanced heart failure and are ineligible for heart transplantation. They are electromechanical systems designed to assume the work of a patient's left ventricle, improve coronary arterial perfusion, and provide systemic blood flow to all tissues and or
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From page 104... ...
Exposed Population For this case study, the committee considered only people who have advanced heart failure, who are generally not eligible for cardiac transplantation, and who may have a permanent VAD implanted. About 20,000-30,000 people may be eligible for VADs, but their use is not yet widespread, so the actual number of people exposed is much smaller than the population of potential VAD recipients.
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From page 105... ...
Less severe adverse health effects that could follow VAD implantation include effects that would follow hospital release, such as drive-line infection, arrhythmia, renal or hepatic effects, thrombosis, and faulty battery or connections. In the current system, the committee assumed that 50% of those living with VADs experienced such effects, or 1,500 people experiencing less severe adverse health effects each year.
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From page 106... ...
Accordingly, Table 5-1 contains a brief description of the expected reduction in the uncertainty in the number of deaths and other adverse effects associated with the enhanced surveillance system rather than precise numbers. Because the current system of postmarket surveillance of VADs is already quite comprehensive and the patient population is small, the expected benefits of the enhanced system compared with the current system are smaller than in the case of artificial knees, for which the enhanced system is much more rigorous than the current one.
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From page 107... ...
Ability to Mitigate Adverse Health Effects As noted above, medical devices are highly regulated, and VADs are monitored carefully. However, VAD patients are generally in advanced heart failure and are more susceptible to surgical risks and to adverse events after implantation than are recipients of artificial knees.
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From page 108... ...
Finally, the committee notes that during the development of this case study, several issues related to medical devices arose that would probably be relevant for other device-related decisions. They include the speed with which health outcomes can be improved if a problem is detected, potentially measured as time between detection and correction; sustained health benefits of a medical implant and the performance of alternatives to the implant, which would be of particular relevance if FDA were evaluating decisions that could change the availability of the implant for potential recipients; and time-dependent projections of levels of exposure and health effects, especially for new products or ones whose use is growing or shrinking.
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From page 109... ...
2009a. Reporting Adverse Events (Medical Devices)
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From page 110... ...
2009. Advanced heart failure treated with continuous flow left ventricular assist device.
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