Story

Hi, my name is Nad Classie. I'm one of the interventional radiologists at Imperial College in London. I'm going to give you a short presentation on cable filters. We're going to discuss some of the underlying disease pathologies that warrant an implantation of this device and then I'm going to show you the two different methods for deployment and then we'll discuss retrieval. Now cable filters are primarily a prophylactic device. They're inserted either prior to major surgery in patients who say have trauma, pelvic fractures and other high-risk procedures which will require them to be bed-bound after surgery so as a preventative measure of thromboembolic disease. They can also be used in patients who have had established thromboembolic disease and either receiving intervention for that or are unable to go on to anticoagulant therapy. The device that we'll be discussing is the Cooke Select device and it can be deployed by two options, either through the venous system in the leg or from the jugular. This is the device and in its present form it's mounted so that it can be delivered through the legs. At the end of the procedure the cable filter ideally needs to be just below the level of the renal veins which are here and the hook which is part of the retrieval system is always pointing cranially. The filter comes preloaded on a delivery system that warrants deployment from the limbs but this can then be switched to a jugular platform quite easily by attaching the hook to the top of the filter. Deployment involves initially a caveogram which is performed at the time of deployment to see where the filter is best placed and to establish the extent of embolic disease. To give you an idea of how this is deployed. I'm just going to give you a synopsis on how it's delivered from the jugular. So having established the jugular access which is done under auto-time control, the system is then introduced and on this cable model the system is introduced from the SVC through the heart down to the region way we want to deploy the actual filter. Through this delivery system you can actually perform the initial cavogram and this gives us an idea of what the anatomy looks like. You can also delineate the level of the renal vessels at this point. Once you have the delivery system in the right position, the introducer is removed and the deployment is then performed through a cartridge mechanism which houses the filter. This has been preloaded now to allow the filter to be deployed from the jugular and as I say this other system shows it the other way around from the leg veins. The system has a non-leak valve which then allows you to introduce the filter delivery mechanism and once you've delineated the level of your renal vessels, the system can be locked in place. The system is advanced to where you want the filter to be deployed and a locking mechanism here allows the filter to be released. Once that's in place, then the mechanism is designed to unsheathe, deploying the filter And when you're happy with your position, a little bit of tension on the filter allows you to deploy it straight and then you just release with the one click and everything else can come away. So that's the filter in position now. Removal is pretty similar but it's always done from a jugular axis and involves a sheath which is introduced. This can then allow the hook at the top of the filter to be snared using what's called a gooseneck snare. This is all controlled by the operator at the upper end. The idea really being is to snare the hook. And once you have the hook snared, then the delivery mechanism just advances over it to retrieve the filter, and then that's all removed through the sheath, which is maintained in place. Afterwards, everything comes out and you maintain haemostasis by compression.