As if this weren't all complicated enough! One more interesting thing that
is emerging in the literature with the new generation(s) of drug-eluting
stents may work too well, that is they may prevent the formation of any
neointimal lining. I have seen a few isolated reports of stents more than a
year out that are completely void of any intimal, ie: still bare metal
inside the artery. This would seem problematic to me......... I agree with
Jean - we clearly do not know much about this - perhaps we simply need to be
smarter!
Bill Schroedter
Venice, Fl
-----Original Message-----
From: UVM Flownet [mailto:[log in to unmask]] On Behalf Of Jean
Primozich
Sent: Wednesday, October 12, 2005 5:12 PM
To: [log in to unmask]
Subject: Re: Carotid Stent Follow up
Gail,
Because we do not yet know the natural history of carotid stents, and
because I believe that there is much to learn about what happens to these
arteries after they are stented, I think that follow up should be done more
often than with carotid endarterectomy; perhaps every 3 months, until we
have some hard data to show that the vessels respond in the same manner as
we espect after endartectomy.
The first follow up post op study should be within one month after the
procedure and bilateral, so as to see if the contralateral side has changed
(decrease flow) due to the elimination of the stenosis on the procedure
side. (Just like with carotid endarterectomy). This should serve as a
baseline scan, at least for the stented artery, and all other follow up
studies should be compared to this study. Since we do not know what the
normal velocity is within a stent or whether it is elevated for reasons not
yet defined, we must keep in mind that this is not a "normal" vessel any
longer. It has scaffolding, i.e. the stent, making the walls potentially
stiffer and it has basically created a theoretical uniform flow channel
without a bulb. It has also been ballooned (perhaps more than once) and has
a metal structure against the walls potentially causing prolonged
inflammation and therefore potential restenosis. We just don't know the
answers yet. Which is why why we have to be very careful about using
criteria that we use for native unstented arteries and criteria that was not
validated according to the NASCET method, that is using the distal ICA as
reference. The old criteria that used the bulb as the reference, probably
should not be used with any confidence for any studies (stented or not) that
we do these days, since all of the angiograms are now being standardly read
using the distal ICA as reference.
I have included two references for criteria that I think look pretty good,
although bear in mind, these are small studies and have not been tested
prospectively or reproduced in other centers. But, nonetheless, the
velocities look like what I might think would be legitimate
(hemodynamically) in a stented vessels. I would be willing to discuss this
in more detail if you would like, perhaps on the phone. Give me a call (206)
685-3225.
References:
Stanziale, SF, et al. Determining in-stent stenosis of carotid arteries by
duplex ultrasound. J Endovasc Ther. Jun; 12(3), 2005.
Lai BK, Hobson RW, Goldstein J, et al. Carotid artery stenting:is there a
need to revise ultrasound velocity criteria?. J Vasc Surg, 2004;39.
Hope this helps,
Jean Primozich
University of Washington
Ø
----- Original Message -----
From: "Anna Marie Kupinski" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, October 12, 2005 5:59 AM
Subject: Re: Carotid Stent Follow up
> Hi Gail,
>
> We usually scan them prior to discharge or at the first post-procedure
> office visit. Then usually every 6 months. The only criteria we have
> is what we currently use for the native carotid vessels. However, our
> velocities tend to be higher so our lower cut off was raised from 125 to
> 150 cm/s.
>
> Ann Marie
>
> Ann Marie Kupinski, PhD RVT
> Technical Director, Karmody Vascular Laboratory
> The Vascular Group, PLLC
> Albany, NY 12208
> phone:518-262-5050
> fax:518-262-6686
>
>>>> [log in to unmask] 10/11/2005 7:47:52 PM >>>
>
> Need some help. Can someone tell me what the usually carotid stent
> surveillance protocol is and what criterias are being used -- Bandyk?
> Jeannie, Anne Marie... Thanks
>
>
> Gail P. Size, BS, RVT, RVS, RCVT
> Educational Coordinator
> www.VASCULAR-WEB.COM
> A Resource for Vascular Professionals
> Western Office
> 13303 S. Desert Dawn Dr.
> Pearce, AZ 856252
> Phone 520-642-1303 Fax 520-642-1304
>
>
>
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