Hello m3krause,
I?ve found no evidence that stents contain beryllium. However,
there are a wide variety of stents, and manufacturers can change
materials over time. What kind of symptoms is your father having that
makes you suspect the stent? As you will read further down in the
answer, stents are usually covered with the patient?s own tissue in a
short time, making a mesh of the stent and arterial tissue. Had the
stent contained beryllium, and your father has a severe allergy, he
would have shown symptoms sooner than 5 years, symptoms that would
have been manifested rather quickly.
I would have hoped that your fathers pre-operative care would have
included a list of allergies. Did your father make this allergy known
to the surgeon? The best way to know for sure if his stent contained
beryllium, is to contact the surgeon for a copy of all medical
records. The brand of stent will be on the chart. Once the date made,
thebrand and model names are known, one can determine if it contained
beryllium. Some stents contain stainless steel, and some are made of
polymers (similar to nylon and plastics). Your surgeon should be able
to tell you if the stent contains beryllium.
Since beryllium is considered a carcinogen (capable of causing
cancer), it is unlikely that stents contain beryllium.
?EPA has classified beryllium as a ?probable human carcinogen.?
Although laboratory animals developed lung cancer when they breathed
beryllium mist or drank water with beryllium, evidence is less certain
that exposure to beryllium can cause cancer in people.?
http://www.aep.com/environmental/emissioncontrol/rtk/chemicalprofiles/Beryllium.pdf
?Stents are stainless steel or nytinol mesh like devices that look
similar to the spring in a pen. Stents are delivered into the coronary
artery on a catheter during a PCI procedure. They are then 'deployed'
in the artery by either expansion by a balloon or by a unique 'self
expanding' delivery design. They serve as a scaffold to prop the
inside of the artery (the lumen) open which increases blood flow to
the heart muscle.
They are permanently deployed devices that stay in the artery. They
are not removed. They ultimately become covered with cells and in
essence become part of the artery over time. One of the early
limitations to stent use was the development of 'Subacute' stent
closure which occurred when blood clots formed within the stent to
shut off blood flow to the heart muscle. Like acute closure, this
frequently resulted in a heart attack or other major complication.
Fortunately, it became recognized that stents had to be deployed
within the artery in a certain manner and that anti-platelet drugs
were necessary for the prevention of subacute closure. With modern
techniques and the use of Aspirin and oral anti-platelet drugs (Plavix
or Ticlid), subacute stent thrombosis is extremely rare occurring in
approximately 1 to 1.5%. Pictured is a Velocity Stent from Cordis.?
http://www.westsubcardiology.com/pages/cath/stents.htm
Now, some stainless steel CAN contain beryllium. Again, you will need
to know the model, manufacturer and date made of your father?s stent
to determine composition. Different formulas for stainless steel are
made, for specific purposes.
Composition of stainless steel
?The one key element that all stainless steels share is a certain
minimum percentage (by mass) of chromium: 10.5%. Although other
elements, particularly nickel and molybdenum, are added to improve
corrosion resistance, chromium is always the deciding factor. The vast
majority of steel produced in the world is carbon and alloy steel,
with the more expensive stainless steels representing a small, but
valuable niche market.
Nickel ranks as the second most important constituent in most
stainless steels. One or more of the following elements also may be
added to iron to make stainless steel: molybdenum, titanium,
columbium, aluminium, nitrogen, phosphorus, sulphur, and selenium.
Each element modifies stainless steel so it can be used for a specific
purpose.?
http://www.ulearntoday.com/magazine/physics_article1.jsp?FILE=steel
?A stent is a stainless steel mesh. It's crimped onto a balloon, and
when the balloon is expanded, the stainless steel mesh is also
expanded, and is essentially embedded into the wall of the artery, and
it acts like a tiny stainless steel scaffold to sort of buttress the
wall of the artery and keep the artery open.?
http://www.pbs.org/newshour/bb/health/jan-june01/stents_3-6.html
?REVA was founded in 1998 to develop ultra-thin, radially strong
vascular stents using tiny ratchet-like elements designed to lock the
stent open and achieve superior radial strength. The "slide and lock"
feature of REVA's stent geometry is designed to provide the strength
necessary to make the stent from polymers. Previous experiments with
bioresorbable stents have generally resulted in designs that required
energy to polymerize the stent after it was deployed, or lacked the
necessary strength to provide a satisfactory clinical outcome. Some
clinicians believe that using stents made from resorbable polymers
will allow them to treat more lesions per patient than metallic stents
or to treat different vascular diseases where metal stents are not as
desirable. REVA is developing an uncoated version of the REVA stent as
well as one coated with paclitaxel. Paclitaxel is the active agent in
Boston Scientific's TAXUS? Express2? paclitaxel-eluting coronary stent
system.?
http://www.teamreva.com/company_news_bsc.html
?Within one month, the stent becomes covered with a thin layer of the
artery?s inner lining cells. It will not be affected by a metal
detector or most mechanical equipment.
http://www.heartcenteronline.com/myheartdr/common/articles.cfm?ARTID=294
?Heart stents are typically tiny wire mesh tubes that are inserted
into blocked arteries in the heart and then expanded to increase the
diameter of the blood vessel and create a free-flowing passage for
blood. Heart stents reduce the need for repeat operations to unclog
arteries and lower the risk and severity of heart attacks and
strokes.?
http://www.heartdevice.com/
Here is a list (Not all-inclusive) of some cardiac stents
http://www.guidant.com/products/stents_us.shtml
Beryllium Allergies
http://www.madsci.org/posts/archives/nov2000/973260622.Im.r.html
I hope this has helped you. If anything is not clear, please request
an Answer Clarification, before rating. This will enable me to assist
you further on this question.
Sincerely,
Crabcakes
Search Terms
cardiac stents + beryllium
cardiac stents
coronary stents + beryllium
beryllium allergies |
Clarification of Answer by
crabcakes-ga
on
20 Jun 2005 18:56 PDT
Hmmmmm. Did your father work in an area where he was exposed to
beryllium? Has your father had any dental fillings recently? Some
dental amalgams contain beryllium.
"Provided that the control measures in the beryllium industry
are adequate, general population exposure today is mainly confined
to low levels of airborne beryllium from the combustion of fossil
fuels. In exceptional cases, where coal with an unusually high
beryllium content is burned, health problems could arise. The use
of beryllium for dental prostheses should be reconsidered, because
of the high sensitization potential of beryllium.
Cases of acute beryllium disease resulting in nasopharyngitis,
bronchitis, and severe chemical pneumonitis have drastically
decreased and, today, may only occur as a consequence of failures
in control measure systems. Chronic beryllium disease differs from
the acute form in having a latent period of several weeks to more
than 20 years; it is of long duration and progressive in severity.
The lung is mainly affected; granulomatous inflammation, associated
with dyspnoea on exertion, cough, chest pain, weight loss, and
general weakness, is the typical feature. Effects on other organs
may be of a secondary nature, rather than systemic. The great
variability in latency and the lack of dose-response may still
occur today among sensitized individuals who have experienced
exposure to a concentration of around 2 µg/m3.
Despite some deficiencies in study design and laboratory
practice, the carcinogenic activity of beryllium in different
animal species has been confirmed."
http://www.inchem.org/documents/ehc/ehc/ehc106.htm#SectionNumber:1.2
I'd be interested to know what kind of stent was used.
"Beryllium will not enter your body from skin contact with the metal
unless the skin is scraped or cut and beryllium particles become
imbedded in the wound.
www.eco-usa.net /toxics/berylium.shtml (1513 words)"
http://www.factbites.com/topics/Beryllium
I'll agree with you that the timing of the allergy and the stent is
suspicious, but it *may* be coincidental. We will never know for sure
without the manufacturer name, model of stent, and date of
manufacture.
Regards,
Crabcakes
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