Calcification is the enemy of PCI—attempting to use a stent before preparing a calcified artery will likely lead to a myocardial infarction! In this case demonstration video, from our Percutaneous Coronary Interventions Essentials course, you'll learn about the methods used to deal with calcification, as well as the limitations of each.
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[00:00:00] Calcification is the enemy of PCI. If you're unable to dilate up a stenosis with a balloon, then it's impossible to treat the patient with stents. Some calcification within the wall of the artery goes completely around the artery known as circumferential calcification. Given its appearance, this is sometimes referred to as napkin ring
[00:00:30] calcification. Basically, you cannot deploy a stent unless you can crack this ring of calcification. If you try to deploy a stent without first preparing the vessel, the stent will not be able to fully expand or oppose the wall. This can lead to problems with flow in the vessel with a result in in-stent thrombosis and subsequent myocardial infarction.
[00:01:00] Calcification is particularly seen in the elderly and as the population ages, it's, therefore, more commonly encountered during PCI procedures. One technique is to use a scoring or cutting balloon to modify the ring of calcification. These balloons work by having metal on the outside of the balloon and delivering focused pressure which leads to linear tears or cracks in the calcification
[00:01:30] so that the artery can then be further expanded with a normal balloon. They can however, be hard to deliver in tight spaces due to the bulkiness of the balloon from the metal component. There are a number of scoring or cutting balloons that are commercially available. So what if we can't insert a balloon because the lesion is too tight or it still won't expand? We either have to abandon the PCI or look to other methods.
[00:02:00] In this video, you can see a rotor bar used in PCI. Rotational atherectomy or rotablation is a rotating bar that is tipped with industrial diamond and rotates very quickly around 160,000 reps per minute. This fragments the calcium into microscopic particles that are absorbed into the distal coronary circulation. Once we have modified
[00:02:30] the calcification, a normal balloon can then be used to dilate the lesion. A limitation of rotational atherectomy is that it's a complex procedure that requires considerable operator experience and training. It also necessitates the use of larger sized guiding catheters and has increased complications of dissection or no flow or slow flow within the artery. Special lubricated stainless steel rotor wires
[00:03:00] are also needed for rotational atherectomy. It is due to the heat generated by the rotating bar. These can be difficult to use and are not as easy to insert into a coronary artery when compared with normal angioplasty wires. If you can't insert a rotor wire through a lesion, you can't rotablate. Occasionally, people use laser catheters to create enough space to allow the passage of a rotor wire to continue then with rotational atherectomy.
[00:03:30] This works because laser catheters can travel over any normal workhorse wire. Whilst they can't deal with calcification on their own, lasers and then a combination of a laser followed by rotational atherectomy, also called razor, can be effective in complex calcified lesions where we cannot pass a rotor wire initially. Newer technologies include the use of sound or shockwaves to disrupt calcium in much the same way that lasertripsy is used for
[00:04:00] renal stones. Sound waves are delivered via balloon inserted over a standard wire. Limitations of this technology include the bulkiness of the balloon which may not be able to pass in severe or tight lesions.