Glenn Barnhart, MD – The Cox Maze IV Procedure: Principle to Practice

Video Categories: Best Practices, Lesion Set, Maze Procedure
2 YouTube Views - Published July 30, 2020
Featured Speaker: Dr. Glenn Barnhart




Video Overview

Dr. Glenn Barnhart discusses various concomitant procedures with a Cox Maze IV.


Video Transcript

For the hearing impaired members of the AFibSurgeons.org community, we have provided a written transcript below: 

Dr. Glenn Barnhart:  I want to spend just a couple minutes talking about a few general principles and specifically address non-mitral procedures. When we're doing – when you're thinking about the Maze procedure and your patient population, you want to understand a few principles of how to adopt the Maze and put it into your practice. 

What are those principles? The most important thing to remember is a primary reason for the cardiac surgery procedure Why are you there? Once you're started, you must be willing to abandon the Maze procedure if there's poor tissue quality, unexpected TEE findings, the operative technical challenges, etc. All of us as surgeons know that these issues arise almost on a weekly basis, and it's important to be willing to back out if you run into those. 

In general, I think it's important to think – to being to think about the – when you're assessing the Maze procedure and the Cox Maze IV to work from the posterior part of the heart to the anterior part of the heart, and I'm going to go into this in a little bit when it's applied to CABG, and AVR and multi-valve. 

If a bi-atrial procedure is planned, be willing to abandon the right atrial procedure if encountering technical challenges with the primary operation. Avoid prolonging the aortic cross-clamp time. The corollary to this is when first beginning, do the right atrial lesion set off the aortic cross-clamp. 

The tissue integrity should be assessed throughout the course of the operation. Abort any time. If you're having trouble and you have concerns about the tissues and how they're being handled – patient's been on steroids or whatever – steroids in my mind are not a contraindication but I think it's something to think about if you got diabetic, small little lady that needs a mitral valve and she's on steroids. That's a patient, in my mind, that I may be thinking about okay, I may have to abort this at some point. 

Let me make a point about venous cannulation. Venous cannulation strategy should be dictated by the planned operation and the guidelines indications for a Cox Maze IV. Venous cannulation should not be dictated by the primary operation alone when the CMIV is indicated. Just because somebody is having a CABG doesn't mean that I don't really want to do bi-cable cannulation. Bi-cable cannulation only adds about three to four minutes, and that should not be a hurdle for the patient not to have a Cox Maze IV if they have very serious atrial fibrillation, meaning persistent or long-standing persistence of AF. 

Let's look at CABG and see how this is different from, say, a mitral. When I do CABG operations, I go on pump and do the right PVI on pump before cross-clamp, place the aortic cross-clamp, do the left PVI, do the left atrial lesion, appendage lesion, do a limited left atriotomy. You don't have to do a huge left atriotomy. You need to see the floor, the roof, the mitral, and coronary sinus lesions. That's all you need to see. You need to be able to see the right pulmonary veins, the left pulmonary veins, and the mitral annulus. 

Depending on which grafts are being done, the right atrial lesion step is next versus the CABG. If the RIMA is being used, you must do the right atrial lesion set first because obviously you don't want that draped across the area where you're working.  

The left atrial appendage clip, the atrial clip, is placed at the end of the procedure depending upon the graft status. If you've used the left internal mammary artery on occasion, I would put that – and so we just put that to the OM or saphenous vein graft is in proximity to the left atrial appendage. I would – in most of those cases, I would not put the clip on, and I would just transect and over-sew the left atrial appendage because I worry about there being friction erosion on the LIMA, which of course coming off from the subclavian. 

For an AVR, what are the special considerations? Again, you want to do the right side pulmonary vein on pump. You want to cross-clamp. You want to put the cross-clamp on and then go examine the aortic root. Again, this gets to the principle of remembering why you're there. You want to examine the aortic root, excise the aortic valve to anticipate the amount of time is needed for the aortic valve. You may run into something, abscess that you don't know about, an unknown VSD or some reconstruction of the root that's going to be very complicated. You want to know that before you get too far deep into doing the Cox Maze IV. Complete the Maze as in the CABG and complete the AVR, place the clip. 

Let's say if you're doing a mitral valve repair, I think we've gone through this completely. We don't need to reiterate on that. If you're doing a multi-valve procedure, you're going to do the right pulmonary veins, do the aortic cross-clamp, left pulmonary veins and left atrial lesion. Again, you want to excise the AV and assess for unknown pathology. Left atriotomy, floor, roof, mitral and coronary sinus lesions – you want to place – do the mitral valve repair and clip replacement. Do the AVR and then finally finish up with the right atrial lesions, then the tricuspid valve repair. Be sure to do the right atrial lesions first before you do the tricuspid valve repair because once the ring is in place, you're not going to be able to get a complete lesion and you'll end up with a gap at the annulus. 

In summary, I think in 20 – I should say 2020 now, we must have a valid reason, I really feel, that – for not performing concomitant AF surgery in patients with a history of AF who are undergoing CABG, mitral valve repair, AVR, or CABG+AVR. This gets into what I was posing to you before. When you're sitting across the table and you're looking at your patient and you know they've had persistent or long-standing persistent atrial fibrillation, I feel that all of us should work toward looking at that patient like you're going to do an ablation procedure, a Cox Maze IV procedure, unless you find some reason not to do it rather than looking for an ideal candidate in whom to do it. Otherwise, I really feel like we're not providing an acceptable standard of care to our patients.