PCI—loading a balloon and pre-dilatation
In this PCI video, you'll learn how to load a balloon onto a wire and deliver it into the lesion. We'll also cover how to troubleshoot the most common problems that can occur during this process.
In this video, from our Percutaneous Coronary Intervention Essentials course, you'll learn how to perform the technique of loading a balloon onto a wire and delivering it into the lesion. What if it doesn't work? What if it slips? We’ll give you all the answers! At the end of the video, we'll review the limitations of using balloon angioplasty alone and when you may need to use something more definitive–such as stenting.
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[00:00:00] Often, we pre-dilate a lesion or stenosis with a balloon before stenting. When we don't pre-dilate but go directly with a stent, we call this direct stenting. Try to choose a balloon that's the correct size for the vessel. Don't initially oversize your balloon and remember, there's always the option to go bigger. The idea is to check that the lesion will yield when pre-dilated
[00:00:30] so it will accept the stent. So conversely, don't use a really tiny balloon that won't help you decide if the lesion will yield or not. For speed, we usually use a monorail or rapid exchange balloon unless you want to swap a wire out or inject distally when an over the wire balloon may then be useful. Ensure that you receive the balloon size that you asked for. Check the packaging and also the size of the balloon hub, and remember that you are the one responsible
[00:01:00] for putting it into the patient. Never assume it's the correct size just because that's the size you asked for. The balloon is prepared or prepped with a mixture of dilute radiographic contrast which is usually achieved or a 50/50 mix of saline plus contrast and allows the balloon to be visualized to check expansion on directory guidance. Connect the balloon hub to lower lock syringe with contrast, invert the syringe, and aspirate a few times
[00:01:30] to remove air from the balloon and replace with a contrast saline mix. Top up the balloon hub with saline and connect to an indeflated device. We then tend to go full negative with the indeflator to remove any further air from the balloon system and ensure the profile of the balloon is as low as possible, and to make sure the balloon hasn't been slightly inflated inadvertently by balloon preparation. To load a balloon onto the wire,
[00:02:00] first wipe the wire with a damp cloth. My tip here is to just be very careful when wiping the wire that you don't inadvertently pull it out. When loading a balloon onto the wire, make sure it's the correct wire you're loading it onto if using more than one wire. Make sure that the wire is fixed with one hand as you slide the balloon along so that it does not move inside the patient. If it moves forward, it may cause distal vessel wide perforation. If it moves backwards,
[00:02:30] you may pull it completely out of your recently wide vessel. Ensure good communication with assistance and cath lab team. Use clear statements like, "I have the wire" or questions like, "Do you have the wire?" before you move anything or let go of any equipment. Wire husbandry is a term often used to describe looking after your wire once it's in the correct place. Wires can be slippery
[00:03:00] and easily move. Wipe the wire to keep it clean and free of blood and contrast which may impede the balloon or stent movement. But again, remember, watch when wiping the wire that you don't inadvertently pull it out of the patient. Open the O-ring enough to allow the device to be passed easily, then close quickly to prevent blood loss and record pressure tracing from the catheter. It's useful to tell the lab staff monitoring the pressure traces
[00:03:30] when the O-ring is open. I say "O-ring is open" or "O-ring is wide" and remember, they can't see what's going on in the procedure from where they're sitting behind the screens and they wonder why the pressure trace has suddenly disappeared or the pressure has dropped. Other hemostatic devices are commercially available such as [inaudible 00:03:49] OK device to name just a few. Get familiar with the one that you use regularly. Hold the indeflator dial down, come off negative
[00:04:00] and back onto neutral. Inflate in a controlled manner, reading off inflation pressures as you go or simultaneously checking the balloon is expanding on the X-ray image and that it is still over the lesion and that it has not ruptured. Sometimes, it's difficult to judge the size of a vessel accurately. Usual pre-dilation balloon inflated to a given nominal pressure and review the chart that comes with every balloon to determine its exact
[00:04:30] size when inflated. Make sure it's inflated uniformly and not restricted by the lesion or the vessel. Use this to compare with your reference angiogram to determine the diameter of the vessel in question. If the balloon inflates too quickly and the lesion does not yield or is rubbery, for example, in instant restenosis, then as it inflates, it may jump forward in the artery, so-called pipping, soaping
[00:05:00] or melon seeding. Watch for this on the X-ray, is if you see the balloon jump forward, it needs to be deflated and pulled back so it does not injure non-diseased vessel. The balloon may also melon seed by jumping backwards as well as forwards. Once repositioned over the lesion, then reinflate very slowly with gentle counter traction on the balloon shaft if it jumped forward or forward pressure if it came backwards until the balloon
[00:05:30] catches in the lesion and can be fully inflated. If it keeps happening, consider switching to a cutting or scoring balloon which may help the balloon grip inside the lesion. Watch the video as the balloon inflates. Keep your eye carefully on the length of wire visible between the tip of the guide and the first radio-opaque balloon marker. Assuming the guide or wire don't move, this won't change during balloon inflation. Can you appreciate,
[00:06:00] as the balloon is fully inflated, it comes backwards or more proximally in the artery and the distance between the guide and the balloon marker shortens. The balloon has melon seeded backwards due to a rubbery resistant lesion. We can then use the deflated balloon to assess the length of a lesion. This is shown in the video. Remember that the balloon has two radio-opaque markers at each end and these are obviously at a specified
[00:06:30] length depending on what length of balloon you've chosen. This can act as a ruler for deciding on length of lesion and subsequent choice of stent length. If the pressure in the balloon suddenly drops or you can't maintain a constant pressure or you see the balloon deflate or contrast enter the coronary artery on fluoroscopy, then it's likely that the balloon has ruptured. If this occurs, the sudden bursting
[00:07:00] especially if it was at high pressure can cause vessel perforation and dissection. If this happens, go immediately to full negative with the indeflator and remove the balloon from the artery, checking with an angiogram for any damage caused. Sometimes you'll see blood enter the hub of the balloon or the indeflator as you go negative which confirms the balloon has ruptured. Reinflating it on the trolley out of the patient will often then confirm the leak
[00:07:30] if you remain unconvinced. Remember, when deflating the balloon normally, pull the indeflator handle back to full negative and watch for air bubbles coming back from the balloon. The bigger the balloon, the longer this takes. Watch for a sudden rush of bubbles towards the end of deflation to signify the balloon is fully deflated. The balloon can then be safely removed from the artery back into the guiding catheter.