Steven Filby, MD, gives a case presentation on optimizing percutaneous LAAO procedure.
Good morning everybody these are my partners disclosures. So imaging for left atrial appendage closure is it's absolutely essential just like it is for any structural procedure. Both pre procedural planning for the procedure itself and to to follow the patient in surveillance conventionally. Pre procedural planning and the device implantation is done with T. And most sites. But C. T. Offers many advantages over T. C. T. Gives you fast noninvasive acquisition. You get ice a tropic data, high spatial resolution three D. Multi player capabilities. And if you consider the absolute complexity of this left atrial appendage this this structure has a myriad of sizes and shapes, Trebek relation and pregnant tissue. All this affects the device going into the appendage. Keep in mind as well that the left atrial appendage is seldom circular and we're putting a circular device into that space. Only about 5% is it circular? Also keep in mind. T. E. is not benign. In this study, 50 patients undergoing structural intervention with T. 86% had some esophageal injury and 40% of those were complex including laceration and hematoma. In addition, I don't know if this is going to play but in addition C. T. Allows us to do fusion which is where we delineate and draw out the left atrial appendage and overlay that on real time telescopic imaging to guide our procedure. So for all these reasons are center moved from this grainy gray scale imaging known as T. E. To cardiac C. T. A. For a pre procedural planning. So our approach using C. T. A. And ice is only employed in about 5% of us sites we do CT pre planning conscious sedation in our device deployment under inter cardiac echo. What we found in shifting from A. T. E. Guided approach from 2017 to 2019. We shifted in 2020 to a C. T. Ice approach. Fewer devices used per procedure. And that's important because that means we're getting it right the first time we're putting in a device it fits it works and we're done with the procedure. The more devices that means you're taking out a device, your instrument in the appendage. It's potentially more injurious to the patient. Keep in mind the left atrial appendage tissue is on average about .6 mm. So very very thin tissue And our procedural success rate went up to 100%. So this is one experience that we published in our sizing methodology and it was based on area derived diameter. So we're using C. T. Coming up with an area derived diameter and making our choice and device selection based on that. And that was really that came from our experience using Tavern right. We used to use T for Tavern device selection and then we had this idea that well seldom is the aortic cannula circular. So to better understand that morphology we use CT and I would challenge you to think of any site today that uses T. E. To this day for Tavern device selection. So these two shapes have the same diameter and most places use maximum diameter for device selection but they have different areas. So with an area derived diameter we came up with successful deployment and 98.5% of our procedures average number of devices 1.0 we're getting it right every single time and the algorithm that we showed predicted the appropriate device 91%. So this was the accompanying editorial sort of a sort of a call to arms because Seti is not being performed as widely as it should. And this editorial called for many of the same advantages that I'm speaking of. So we shifted then from using C. T. For for pre procedural planning and incorporated our plans or our workflow to have C. T follow up in surveillance. So we're using it both to plan our procedure and to follow the device at four months. And this has really helped to inform our decision making for planning the procedure as well. Because one thing that we came up with is is that if the appendages particularly elliptical or if the device is depth limited. If the appendages depth limited, the device tends to shift and can't and it creates exposure of the frame fabric seen through which we see leak. So what you see on this on the on the right panel there is that the face of the devices through um boast but there's contrast getting around it. So this is significant leak. What we want to see with a good closure is absolute no no, no contrast whatsoever. Complete thrombosis of the appendage. So we shifted now and we're using an area derived diameter. And if there's a choice between two devices within the appropriate compression range 10-30% we're going with the lower of the two compressed devices that's less likely to tilt shift and cause this leak. So some of the advantages that have emerged, improved procedural efficiency with ct over ice, improved accuracy, possibly safer. And with our initial experience that we published, we noticed that patients were bored the next day. We were keeping them overnight. They were wanting to go home. So we started sending these patients home and this was around covid as well. So we shifted to a same day program, same day discharge program. We took a step back. We codified our approach. We came up with an algorithm, a systematic way of doing this. And this is our initial published experience. The patients were coming back so we're effectively planning the procedure. It was more effective. It was safer, they were able to be discharged because we were not using general anesthesia. We were not doing esophageal intubation. The patients were going home the same day. Not only that, but we saved money which the hospital likes 15% cost reduction with that protocol. So our success rates have been great devices per procedure just about 1.0 length of case even in a training institution less than average. And it's fueled our program growth. What we've seen is reduced bed occupancy, reduce costs, reduce complication that further drove increase in program growth. That really paid it forward and improve patient satisfaction. That's not something that we've directly measured. But when the contrast shortage occurred a few months back we started average and we started informing patients that we're going to go back and use T. E. Again and patients this is not a symptom driven therapy. So patients said well we'll wait we're gonna wait for the contract because we don't want to have a T. So we, in in conjunction with working with our advanced imaging colleagues came up with a protocol using M. R. I. And this is from data that we published that we presented just recently a T. C. T. First experience using cardiac M. R. I. To for pre procedural planning for left atrial appendage closure turns out it's pretty good. It's about as good as T. About 80% accurate in device selection based on cardiac M. R. I. Measurements. So new developments what's coming down the pipeline. Well three d. and 40 ice certainly attractive where you can place the ice probe in the left atrium and get circumferential measurements and volumetric assessment gives you a lot more information than the to de ice probe. And then there's also this purpose driven software that's been developed with true plan and fi ops and this is an example of what we can get with True plan. You get three D. Segmentation, you get automatic sizing compression estimates, report generation, it can plan your trans septal puncture this assessment can be ruled out and you can simulate the working views that you utilize for your procedure. Other technologies coming down the pipeline may offer more conform a ble devices. So right now, every single millimeter matters when you're choosing a device. If you're off a few millimeters you can have the advice pop out of place. It can't it can tilt it can cause leak. Obviously if it's too small it can release. So some devices that are coming down the pipeline may be more compliant. So there could be more of a one size fits all approach for this procedure that that remains to be seen. So just briefly, I'll finally get to my case example now how much do I have? Two minutes? That's great. I did. Well, okay, so this is this is sort of real time pre procedural planning using C. T. I'm squaring off across the left atrial appendage. I'm identifying it and putting my planes across on the NPR images. You can see it's a pretty complex appendage morphology so it's a reverse chicken wing with a proximal lobe. I'm able to size it, choose a device placed that device in the appendage. See how it simulates when I can move it around and see how it's going to potentially predict how it's going, how it's going to fit into that space. You can see in the bottom right panel that's a 3D reconstruction. So I'm looking at the device inside the appendage as it relates to my predicted landing zone. Just in the interest of time I'm going to go through And I can predict my working angle. So you can see here this is the on the left is the angle that that's simulated by my true plan prediction Elio one card 11. And this is the image that I obtained during my angiogram. During the procedure. I can plan my transept all. I can figure out exactly where on the fossa that I'm going to puncture and get the best co actuality for delivering my device. And here the devices placed. You know, despite the complexity of that anatomy we have a very good position covering both the proximal lobe and the distal appendage. And with ice on the right panel you can see that there's no leak around the device. So seti is superior clearly to T. E. In defining the left atrial appendage anatomy it allows for better pre procedural planning including the trans septal puncture proved improve patient experience improves procedural success efficiency and resource utilization. It certainly should at this time be the preferred imaging modality for planning. Left atrial appendage closure, it hasn't been as widely adopted as you would expect and part of that is due to a lack of familiarity and comfort with CT technology, but with increased utilization of ice and a shift towards a combined Ct ice strategy, as well as the expansion of this purpose driven software that we spoke of. I think you're gonna see CT expansion for this procedure in the future. Thank you very much.