Updated: Apr 21, 2019
The over-the-wire (OTW) technique for IVC filter placement was designed to improve the deployment and subsequent positioning of IVC filters while minimizing complications such as filter tilting. In episode 35 of the BackTable Podcast, Dr. David Mobley discusses IVC filter stabilization techniques during guidewire removal, periprocedural insight, and preferred vascular access sites for OTW IVC filter deployment.
The BackTable Brief
Following IVC filter deployment, careful removal of the Bentson guidewire is critical to prevent filter tiliting; abutting the dilator and sheath against the inferior aspect of the filter stabilizes it when removing the wire.
Dr. Mobley prefers using the OTW technique during femoral access cases, however, he uses traditional techniques when jugular access is obtained.
Cavography following IVC filter placement is not required, yet Dr. Mobley performs it to visualize the IVC and confirm filter positioning regardless of the IVC filter deployment technique.
Current ACR-SIR-SPR guidelines recommend patient reassessment for the timing of filter removal 3-6 months after initial placement; Dr. Mobley suggests reevaluation sooner than three months may be beneficial.
Dr. Mobley prefers using the exchange length Bentson guidewire for OTW IVC filter deployment, though he has used the stiff Amplatz guidewire successfully as well.
Disclaimer: The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
Minimizing Filter Tilt During Bentson Guidewire Removal
Careful removal of the Bentson guidewire after IVC filter deployment is critical to prevent filter tilting. There may be occasional tension when removing the Bentson guidewire, which is caused by the guidewire catching on the edge of the filter. Dr. Mobley suggests abutting the dilator and sheath against the inferior aspect of the filter’s apex to stabilize it. Performing this technique while removing the Bentson guidewire minimizes filter displacement after it has been deployed. One of the most important things for the deployment is once your filter is deployed, you'll see that it's very stable in the IVC. So what you have is, you have a sheath that's been pulled down, it's usually a couple of centimeters below the deployed filter. Your dilator will be pretty much within that sheath, or just a little beyond, or maybe a centimeter below the lowest level of the legs and you'll still have that wire up into the SVC. One of the most important things is the removal of that wire through that filter. What you do is you keep tension, and keep the dilator, and sheath right where they are, and you gently pull down on the exchange length wire that you have. Usually, it comes out with no tension, very easily.
Every once in awhile, the very small micro loops that these steel Bentson wires are made of can get caught and cause friction on the edge of this filter. And so under fluoro, you'll see that the filter is pulled down and you'll feel that tension pulling down. If that happens, what's happening is, you've got show us enough of a tilt for there to be friction on the edge of the filter and the wire. What you need to do is, keep that sheath in the same place. Push the dilator up into the sub apex where the wire goes in inferiorly through that hole. It supports the filter and just puts it off its axis, so that it takes that tension of the Bentson wire edge off of that. And I've never not been able to pull it out easily.
[Michael Barraza] That makes sense. With the position of your sheath, it's not going to displace the filter either.
[David Mobley] It doesn't. It's just a touch of tension, just to push it off to get it off its axis. That's probably the crux of the very end because you're deployed, you're done and you start pulling and then you can definitely pull down, and causing extra tilt on that filter.
What is the best access point to use when using OTW IVC filter guidance?
The OTW technique can be utilized through any access as long as there is a straight longitudinal course to the IVC, says Dr. Mobley. Stent deployment from femoral access sites may be associated with increased tilting when compared to jugular access deployment. For this reason, Dr. Mobley prefers to use the OTW technique when deploying from a femoral access point. For cases requiring jugular access he continues to use traditional IVC filter placement techniques.
[Michael Barraza] My understanding is that you should be able to do this from really any access that you could place the filter from as long as you have that straight longitudinal course.
[David Mobley] Absolutely. We tried it once or twice from a jugular access, and we tried it from both femorals. However, when we were looking at this, we really just wanted to study it from one area that most people use in the country. That's either the right jugular or right femoral, and since the femoral seemed to have more tilting, that's what we decided to compare it to.
[Michael Barraza] Is this the primary filter you guys are using or is it a good mix?
[David Mobley] We used to have more of an even mix between all the filters, but with this study and working with it, we are definitely primarily using Option filters. However, we are an academic center, we train residents and fellows and they need to understand how to use different filters, and how they feel, and how they deploy. We do have a little bit of a distribution between various filters, but primarily we're using Options.
[Michael Barraza] Okay. And when you're placing them personally, do you prefer to do them over the wire?
[David Mobley] If I go femorally, I do them over the wire. If I go jugularly, I don't go over the wire.
What type of wire is used for OTW filter placement?
[David Mobley] I tried a few of them with the stiff Amplatz and it worked just as well. I didn't see any difference. Since I had started with the exchange Bentson, I just kept going with that. But the stiff Amplatz works very nicely as well.
Do you do a repeat cavogram after OTW filter placement?
[David Mobley] I do them regularly, yes. I did it every time when we were doing the study. Some of my partners do it and some of them don't. I routinely do whether I go juggularly over the wire, not over the wire, or transfemorally. I routinely do a post-positioning a cavogram.
When do you bring patients back for filter retrievals?
[David Mobley] It depends. We try to get them back within three to six months, sooner than that is even better. But generally speaking, with the patients that we have here, whether it's postsurgical or whatever it happens to be, they tend to need a higher level or a longer follow out with their treatments. For us, even though we'd like to catch them before three months, we usually catch them when we do and I'd say between three and six months.
Dr. David Mobley is a practicing interventional radiologist at Columbia University in New York.
Dr. Michael Barraza is a practicing interventional radiologist at Radiology Alliance in Nashville, Tennessee.
Cite this podcast:
BackTable, LLC (Producer). (2018, November 12). Ep 35 – OTW Technique for IVC Filter Placement [Audio podcast]. Retrieved from http://www.backtable.com/podcasts
The Materials available on the BackTable Blog are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
The podcast referenced in this article was sponsored by Argon Medical Devices.