Show #6, July 2002
Show #6, July 2002
|FDA Approves Combination Cardioverter and Defibrillator for Heart Failure Patients|
FDA recently approved a new implantable defibrillator for certain heart failure patients that can also deliver cardiac resynchronization therapy. It's called the Contak CD, and it's made by the Guidant Corporation of St. Paul, Minnesota.
It's intended for patients at risk for life-threatening heart rhythm problems who also have symptoms of advanced heart failure that are not adequately controlled with medication.
The device consists of a pulse generator that's usually implanted under the skin beneath the scapula. Three leads from the pulse generator are threaded through a vein to the heart. One goes in the right atrium, one goes in the right ventricle, and one goes in a coronary vein that overlies the left ventricle.
Heart failure patients who are candidates for this device are at risk for serious arrhythmias. When the device is performing its defibrillator function, it senses these arrhythmias and delivers a low energy shock to restore normal rhythm. In this way, it treats sudden cardiac arrest.
These patients also have lost normal synchronization in the contractions of the left and right ventricles. When the device is performing its cardiac resynchronization function, it coordinates and normalizes the contractions of the ventricles. This may improve cardiac output and thus mitigate some of the symptoms of heart failure, such as fatigue and shortness of breath.
This device should not be used in patients whose heart failure is reversible, or who can be treated successfully with medication.
FDA's approval of the device was based on two multicenter clinical studies conducted by the manufacturer, involving about 700 patients over a period of about six months. The results showed that the patients in whom the resynchronization feature was used experienced improved exercise capacity and quality of life. However, the studies did not show whether or not the device ultimately affected patient survival.
FDA is requiring the manufacturer to conduct a post-marketing study of 1,000 patients over a three-year period to determine the product's effect on patient mortality, and to better evaluate long-term safety.
- CONTAK CD® pulse generator and the EASYTRAK® left ventricular coronary venous lead - P010012. May 2, 2002.
|New Product for Treating Burn Scars|
FDA recently approved the use of a product to treat severe scars in burn patients by helping the body to regenerate normal dermal tissue. Severe burn scars can be disabling because they lack elasticity. This prevents normal stretching of the skin and interferes with mobility.
The product, the Integra Dermal Regeneration Template, is manufactured by Integra LifeSciences Corporation of Plainsboro, New Jersey. It was previously approved for burn treatment to help repair the skin.
It's a membrane system that's placed over the scar site after the damaged tissue is removed. It consists of two layers. The deeper layer, called the dermal layer, is a lattice of cross-linked collagen fibers that acts as a template to help organize the regeneration of dermal tissue. This layer is left in place and gradually absorbed.
The outer layer, made of silicone, acts like a synthetic epidermis. It helps to close the wound, giving strength to the deeper layer, and limiting moisture loss. This outer layer is removed after several weeks and replaced with a thin skin graft.
FDA's approval was based on a clinical study of safety and effectiveness performed in Europe, in which 30 scarred areas were successfully treated in 20 patients who had had severe burns.
This product should not be used on patients sensitive to bovine derivatives or chondroitin.
|FDA Assesses Safety of DEHP Plasticizer|
FDA is issuing a Public Health Notification informing practitioners and facilities about a possible hazard to patients when medical devices containing the chemical DEHP are used.
DEHP is a common ingredient in plastics made of PVC, or polyvinyl chloride. DEHP acts as a softener to keep the plastic from becoming hard and brittle. Everyone is exposed to PVC plastic everyday and thus to low levels of DEHP. Of course these PVC plastics are used in many medical devices, such as IV bags and various kinds of tubing. Patients can absorb DEHP from some of these devices, and that's where the potential problem lies.
The FDA notification explains that exposure to DEHP has produced a range of adverse effects in laboratory animals, but the ones of greatest concern are effects on the development of the reproductive system and normal sperm in young male animals. The notification points out that there are no reports of these kinds of effects in humans, but there are no studies to rule them out.
Two factors determine the degree of risk to patients. The first is the patient's sensitivity to DEHP. The FDA notification states that based on the animal data we just talked about, male neonates, along with male fetuses and males at puberty would appear to be the most sensitive groups. The second factor is the amount of DEHP received by the patient, and this is determined largely by the type of procedure performed.
That being the case, the FDA compared the exposure to DEHP from various medical procedures, and identified several that would deliver the highest exposure to patients. These include exchange transfusion, ECMO, TPN when lipids are in a PVC bag, and enteral nutrition.
The FDA notification recommends that when these high-exposure procedures are done on male neonates, male fetuses, and males at puberty you should consider using PVC devices that don't contain DEHP, or using devices made of other materials than PVC, such as silicone, polyethylene or polyurethane. What about other patients, who are presumably at lower risk? For these patients, the notification states that the decision to use DEHP alternatives must take into account the medical advantages and drawbacks of the substitute materials, and their availability. The FDA notification stresses that high exposure procedures should not be avoided simply because of DEHP exposure. The risk of not doing a needed medical procedure would be far greater than the risk from DEHP.
If you'd like to see FDA's complete safety assessment of DEHP, you'll find it on our web site.
- FDA Public Health Notification: PVC Devices Containing the Plasticizer DEHP. July 12, 2002.
- Safety Assessment of Di(2-ethylhexyl)phthalate (DEHP) Released from PVC Medical Devices.
|FDA Cites Drawbacks of Whole Body CT Scanning|
Lots of people are interested these days in whole-body CT scanning, where healthy people can walk in and be screened for a variety of disease conditions. This type of screening is being widely promoted, and it's had great deal of coverage in the press. Here's some information you may want to pass along to your patients.
Proponents of whole body CT screening claim that it enables people without symptoms to find out as early as possible about diseases they may have, so that they can get early treatment. They cite peace of mind as another benefit - that is, the comfort in finding out that the scan has not detected a disease.
But there are serious drawbacks to whole body CT screening for healthy persons, and the FDA is recommending that people consider those drawbacks before they decide to have one of these scans.
First of all, no manufacturer has submitted data to the FDA that demonstrate that this kind of screening is safe and effective. Statements by facilities that perform these scans that imply that the FDA has somehow "approved" or "cleared" or "certified" CT devices for screening are simply not true.
There's also the issue of false positives and false negatives. False positive results, in which the scan indicates abnormalities that don't exist, can lead to more tests and medical procedures, some of those carry their own hazards. And ironically, instead of providing peace of mind, they induce needless anxiety. False negative results, in which the scan fails to pick up an abnormality, can lead to a false sense of security, and they cause an inappropriate peace of mind - which can be dangerous because it can prevent the person from getting proper diagnosis. The point to remember is that these whole body CT scans we don't have good data on how often these false positives and false negatives occur.
And last but not least, these whole body scans deliver a radiation dose much larger than most conventional diagnostic x-ray procedures. And that brings up its own long-term health hazard. The principal radiation risk from medical x-rays, including CT, is the possibility of slightly increasing the probability of developing cancer later in life. For a patient with a real medical need, the benefit of the x-ray procedure far outweighs the risk, even when the radiation dose is relatively high. But with these whole body CT scans, where the benefit is doubtful, the potential harm from the radiation may be greater than the presumed benefit from the scan.
FDA isn't the only organization concerned about this issue. The American College of Radiology, the American College of Cardiology, and the American Heart Association do not recommend whole body CT screening for healthy, asymptomatic people.
Here's what the ACR had to say in a recent press release:
The American College of Radiology at this time, does not believe there is sufficient scientific evidence to justify recommending total body CT screening for patients with no symptoms or a family history suggesting disease. To date there is no evidence that total body CT screening is cost effective or is effective in prolonging life. The ACR is concerned that this procedure will lead to the discovery of numerous findings that will not ultimately affect patients' health, but will result in increased patient anxiety, unnecessary follow-up examinations and treatments and wasted expense.
Bear in mind that CT scans are a valuable and proven diagnostic tool when used to help detect and diagnose specific diseases in patients who have symptoms. The concern here is using these devices for screening in healthy, asymptomatic people. The bottom line is to think twice before undergoing whole body CT scans, because the harm may outweigh the benefit.
- Brochure: Full-Body CT Scans - What You Need to Know.
- Whole Body Scanning Using Computed Tomography (CT). April 17, 2002.
|Cell Phone Safety|
Here is another concern that patients may have. Those who use cell phones may wonder whether the radiofrequency energy emitted by these phones might be harmful to their health. If your patients have questions about this, there's now a place you can find answers. The FDA and the Federal Communications Commission, or FCC, have recently created a joint website called, Cell Phone Facts. It provides information about the safety of cell phones, how they work, and how they're regulated.
- Cell Phone Facts; Consumer Information on Wireless Phones.
- FCC News Release: FDA-FCC Cellular Phone and RadioFrequency Energy Website Posted for Public Use and Comment. May 8, 2002.
|FDA Launches a New Campaign about Diabetes|
Diabetes affects more than 17 million Americans, and women are at higher risk than men. Yet many of them don't know they have diabetes. And so to raise women's awareness of diabetes, FDA's Office of Women's Health, in conjunction with the U.S. Department of Health and Human Services, has recently launched a nationwide campaign called "Take Time to Care About Diabetes."
The three key messages are:
* Get tested for diabetes
* Watch what you eat and get exercise, and
* Use medication wisely.
The campaign is being co-sponsored by the American Diabetes Association and the National Association of Chain Drug Stores. As part of the campaign, 10 cities across the country where there's a high rate of diabetes will be having various screening events. Free educational materials and Diabetic Management Kits will also be available in grocery stores and pharmacies.
The campaign will stress the need for women to recognize the early signs of diabetes, to see their doctor about detection, and to understand the serious complications of this disease, such as heart attack, stroke, blindness, loss of limbs, and difficulties during pregnancy.
|You Can Discuss Medical Device Issues with FDA|
FDA's Center for Devices and Radiological Health is looking for people who have an interest in medical devices or radiation-emitting products, so they can be invited to discuss policy issues about these devices. To do that, FDA maintains a database of people interested in interacting with us. You can join the database by going to this story on our web site. It's easy, and there's no charge. Once you've signed up, we can get in touch with you when an issue we want to discuss comes up.
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