Ismail El-Hamamsy, MD, PhD, Professor of Cardiovascular Surgery, discusses The Ross Procedure, providing a step-by-step guide to optimize long-term durability and reviews what is new in the literature on this procedure. This Grand Rounds presentation from the Department of Cardiovascular Surgery at the Icahn School of Medicine will enable viewers to:
• Describe the surgical steps of the Ross Procedure
• Summarize possible operative pitfalls and anatomic limitations associated with the Ross procedure Good morning everybody and thank you for joining this morning's talk. As you know for any repair reconstructive operations. Um Technical details really matter not just in terms of safety of the operation, but really in terms of long term durability of the operation and the ross procedure is no different than any of these operations. Um So the focus of this morning's presentation will really be on all the little step by step. Technical details which are really all based around understanding of the anatomy of the aortic root for optimizing long term durability after the ross procedure. Mhm. This is my ross experience. So what I will tell you today are lessons learned from the literature and also lessons learned from my own practice and experience with the ross procedure. But the main principles when performing the ross are that a the pulmonary autographed is a living structure and like any living structure, it is capable of adaptive remodeling to its new environment. So although we take the pulmonary autographed from a low pressure system, it can adapt to the higher pressures on the left side. However early autograph dilatation begets late autograph dilatation. So the key principle is to really avoid this early dilatation of the autographed and I'll show you how we do that. The other important principle is that if we have a normal or if we can preserve a normal annular diameter and a normal sign of tubular junction diameter, there will be no aortic regurgitation and val function will be very durable over the long term. So stabilizing the analysts and the S. D. J. R. Two of the key points when performing a ross procedure and finally, patients with aortic regurgitation have been shown to be associated with a higher risk of re operation in the long term, but that comes with similar survival benefit in the long term as well. So in other words, the re operation maybe a bump on the road but it does not impact the survival benefit observed with the ross procedure. And again like I said, this presentation will all be technique except for the next three slides. But I'll just show you some of the data around they are because I think there are a lot of misconceptions around that. This is from Tyrone David series of 200 plus Ross patients. And what he showed was two things Patients that had a large or dilated aortic annuals pre operatively as defined by an annualized diameter of 27 mm or more, had a higher rate of re operation at 15 years after surgery. And similarly patients who were operated for aortic insufficiency as opposed to aortic stenosis, also had a higher rate of re operation in the long term. That being said, if you look at the rate of re operation in these patients At 15 years, patients with a I had a freedom from Riyadh of 84%. In other words, about a one annual re operation rate for patients who are in their thirties at the time of surgery. So certainly very good durability data, although higher than patients with is nevertheless not a reason to abandon the rust and patients with aortic regards, but rather it cause to improve the surgical technique and understand why these patients come back for re operation. And in this state of the art review published a couple of years ago in Jack. Ah All of these are the largest long term series of Ross patients published in the last 10 years or so. And what you'll notice is that in all of these series, the rates of patients with pure Ai or mixed say ranged anywhere from 20 to 50 in all of these series. And yet survival of these patients altogether was exactly identical to that of the general population at 15 and 20 years. Of course, these are highly selected patients. But what I'm trying to say is that aortic regurgitation in and of itself is not does not impact survival in the long term, but perhaps a causes a slightly higher rate of re operation. So, in terms of rust durability of one is to think of a spectrum of risk of re operation. In the long term, the highest risk would be in patients with aortic regurgitation with a dilated aortic analysts and a mismatch between the aortic analysts and the pulmonary analysts. And on the other end of the spectrum, you have the Ideal patients in whom the Ross is a particularly durable operation, patients over the age of 50 female patients, patients with isolated aortic stenosis and patients with normal aortic dimensions. So now in the next slides, I will really go step by step as how we do the ross procedure in order to try to mitigate the risk of autographed annotation and re operation in patients after the ross. And this was all published in much more detail in this paper in the annals of thoracic surgery a couple of years ago. The first step when performing a ross is to calculate the aorta very distantly into the aortic arch. The reason being twofold. First, it keeps the cross clamp high in the order to and away from the above the pulmonary bifurcation. So it leaves more aortic space. And it also makes the distal pulmonary anastomosis much easier at the time of harvest because of the because of how distal the cancellation site is. All of these patients are calculated over a wire under trans thoracic are sorry transfer of Fiji electrocardiograph IQ guidance. Looking at the wire in the descending aorta and using this cannula which is pushed and um into the aorta and placed in the approximate descending aorta. Once that is done, the orders clamped and the heart is stopped and then the valve analysis and assessment is performed. As you can see here this is a unique aortic valve with the typical left non commissioner place posterior lee. One of the more important elements that I look at is symmetry of the commissioner and the two Raffaele's that you can see here. You see the two anterior placed Raffaele's and the Commissioner post. Eerily in these patients with unique aspect or sometimes bicuspid aortic valves. The Commissioner and the Raffaele's may not be positioned At 120°.. And when implanting the pulmonary autographed, it is very important to avoid simply following the landmarks on the patient's aortic side because the commissioners on the pulmonary valve will always be positioned at 120°.. So very careful assessment of where these are positions and replacement or repositioning of the com assures is important when implanting the pulmonary autographed. The next step is coronary mobilization. This is just a little schematic to show. Um the principle is really to mobilize it in a rectangular shape, leaving about 2-3 mm around the coronary. Awesome. The reason why I like to mobilize it in rectangle is this, avoid avoid any potential tor shin of the coronary at the time of re implantation. And I always put a future at 12:00 again, just to mark where the north of the coronary is principal when re implanting coronary. As in any route surgery is to avoid any tension portion or Qingqing. And this rectangular shape and that little future will avoid the torch in component of it. So as you can see the scissors are brought down On either side of the left main here, leaving about two on both sides of the left main and extending the incision Just about two below the Austin of the coronary artery. One of the important principles is to avoid leaving too much tissue below the coronary awesome itself because that can cause some stenosis during diastolic and then to mobilise the coronary, you need to remember that the what we're trying to do is mobilize the aorta away from the coronary rather than the coronary away from the aorta. So with the low grade Kateri you stay away from the coronary course itself, but rather just burn parallel to the aortic root. And that detaches the coronary from its implantation to the aortic root. And it mobilizes it just enough to be able to re implant it in its respective sinus without any torch in uh and without causing any kink. Which can happen if the, if there's over mobilization of the coronary, particularly along the first few millimeters in its course, you see the right here has been uh fashion and rectangle shape. And then here we with the coterie we'd just mobilize the aorta away from the coronary. And we really stay away from doing any mobilization around the coronary or around a few, the first few millimeters of the coronary takeoff. You see here at the base of the right ventricle. This is all you need to do to mobilize that right coronary artery and you keep it in its in its sheath, which avoids any qingqing and avoids having to implant the right coronary, very high up in the aortic root. The next step is harvesting the pulmonary autographed. You can see here there's a sucker that pulls the heart down, which linearize is the pulmonary artery. And we use the right pulmonary artery as a landmark and make the initial incision a few millimeters proximal to the epa. And then fully transect the pulmonary artery as you can see here. Once the transaction is complete, the pulmonary arteries then lifted off the plane of the heart of the horizontal plane into in a vertical fashion. And that allows to to take the pulmonary artery away from the left main artery that you can see here in the back. So there's very loose connective tissue keeping the pulmonary artery on the bed of the heart. And this is just undone with low grade Kateri as you can see here. And what we try and do is keep the forceps right there, pulling in this direction, the assistant pulls the autographed vertically. And all this little loose connective tissue is undone until we reach the base of the heart or the base of the infant tubular muscle, posterior. Early as you can see here in that video, once you start seeing that muscle, you know that you are below the plane of the actual pulmonary valve and there's no need to dissect any further than that. You see the osteo of the left main, right here. The course of the left main will be somewhere like here like this. Um It splits into L. A. D. And circum flex right about there and then the first sector will be will take rise right about where the coterie is right now, but again by staying very close to the pulmonary artery and working your way down gradually with low grade katari and pushing the that connective tissue that really and does it without, or at least with very minimal risk of any coronary injury, whether to the left main the lady or the first step to you see here all that infant tubular muscle in the back. Once you've reached that, you know that you were below the pulmonary valve here, we're showing the course of the left main. You see the Austrian right there and then it runs post seriously. So you see that there's a lot of distance between the pot. Once it's been lifted off the plane of the heart. And you can see the lady there laterally to the to the next step is then examining the leaflets themselves. So the important thing is to make sure that we have a try commissioner pulmonary valve, We look inside, make sure we have three Commissioners and three leaflets that there are no major ministrations in the preliminary casts. Once that is done then we mark our proximal incision. And what I what I do is go just below the nature of the non facing leaflet right there. So looking from the inside, going about five millimeters below the nader because it's the lowest point in the in the valve insertion and then crossing into the R. V. O. T. You see the insertion point right there. What I'm drawing with the pen would be the position of the hinge point of the leaflets along the pulmonary analysts. And so by going below the lowest point, if you then cut in a uh in a straight line, you are sure to be below all of the leaflets and not to injure them as opposed to making the initial incision below the commissioner, In which case there's always a risk slight risk of injuring the nature of the bottom of the leaflet. On the pulmonary side. The R. V. O. T. Is then open and under direct vision. It is completely mobilized and cut, looking inside and always staying very close to the leaflets. There's no advantage in taking a lot of muscle away from the right ventricle, so staying just about 3 to 5 millimeters below the hinge point of the leaflets. And then once you reach this posterior portion, this is where it becomes septal muscle. So then we just connect the two edges, bye cutting the into the right ventricular portion of that intervention, regular septum. And then just carving the the that plane in the back. To harvest the autographed fully. And you can see that the the Kateri cuts in a plane that is horizontal to the, to the floor if you want. In a way that that uh dissection plane in the back is a flat dissection plane and you're not digging into the inter ventricular septum, which then would pose a risk in terms of injuring the first septal artery. The first step to lies right about where the katari is. Now, it arises from the L. A. D. And crosses through the septum and makes its way into the right ventricular and Bacardi. Um Right about here. It's usually it rises or it makes it to the surface about one centimeter below the nature of that non facing leaflet. So again, by staying about five millimeters close to the hinge point and by keeping that dissection plane horizontal, it is very rare that that first step to will be injured. Then the next step is implanting the autographed on the aortic side, and the approximate future line is really important. One of the early mistakes that were made with the ross procedure was living a long sleeve of muscle under the insertion of the leaflets on the pulmonary side and just sewing that onto the aortic analyst. What that does is that then sits the pulmonary autographed in a sucre annular position. And remember anatomically the recruit and the pulmonary roots are two very different structures. While the aortic analyst has a very thick fibrous portion to it, the pulmonary analyst has no fibrous portion to it. In fact, it is pushed upward by that infant popular muscle. It does not sit within the fiber skeleton of the heart unlike the three other valves. And you can see that even that infant popular muscle creeps into the base of the pulmonary artery right there. Once we harvest that pulmonary artery, that muscle becomes completely de vascular arised and necrotic and provides no structural support to the pulmonary route. And therefore it's really important to trim that muscle very short, leaving no more than 2-3 mm below the insertion of the leaflets. And importantly, it's important to implant that pulmonary valve within the aortic annuals or inside the bot so that the native aortic annuals actually acts as a support to the pulmonary valve. So you see, once we've harvested the autographed, we further uh, respect that excess muscle below the insertion of the leaflets, leaving no more than a couple of millimeters. And we also scallop it to give it a crown shape such as the aortic normal aortic analysts looks like. And then in terms of the infra annular placement of the pulmonary autographed on the aortic side. As I mentioned earlier, what we want is really to implant that pulmonary autographed deep below the the aortic analysts as opposed to putting it above the arctic angelus to do so. The futures are we use interrupted for a protein futures to do this approximate future line. Uh It distributes the stress better. But importantly, it allows very precise placement of each and every one of these futures by placing it inside the L. V. O. T. On the aortic side and by placing it right at the hinge point on the pulmonary side. The one point that I will stress is commissioners symmetry as I mentioned earlier, especially in patients with unique custody aortic valves as well as those with bicuspid aortic valves, particularly the type zero bicuspid aortic valves. It is important to take a sizer that has three markers at 120°.. Place it inside the aortic root and make sure that whichever three uh locations we used for the Nioka measures are placed symmetrically and one to another because otherwise we induce or cause distortion within the pulmonary autograph and that will cause valvular dysfunction. Um This is the sequence of future placement. I started in the nature of the right, working my way towards the right, left, common, sure, and then completing the left sinus and then starting again at the nature of the right and then finishing off with the non coronary sinus. This is what the future replacement looks like on the pulmonary autographed side. Um On the left side is just a diagram. This pretending to be the prelims future. It goes in right at the hinge point of the pulmonary autographed and it comes out in a tangential fashion, trying to exit at a level slightly higher then the insurgent point of the leaflet and that really pushes the autographed again inside the aortic root or inside the arctic analysts. This is what it looks like on the autographed side. You see these futures are all placed individually from inside out and on the aortic side you will see that the future is placed comes in very close to the analysts and comes out very deep in the L. G. O. T. To ensure that the future is that the autographed is really pushed in. And you see here we see the hinge point and then we traveled tangentially through that wall to push the autographed deep in the L. Vot again, this is another illustration. You see the future coming out deep in the L. V. O. T. And on the autograph side you will see that the right at the hinge point right there and then the tissues pulled so that the future comes out at a level higher than the insertion of the leaflet. Once all of these futures are past, the autographed is then lowered into position is parachuted down and each of these futures is tied individually. This uh ensures a really him a static structure line. It is exceedingly rare. There's any bleeding from that structure line. There is no uh pericardium or filter any other thing required, at least for him, a static purposes. And it also distributes the attention and it allows the route to expand in a very symmetrical shape during Sicily. In terms of coronary re implantation, it is rather simple in the ross. You just place it exactly in its uh its corresponding sinus right in the body of the sinus itself. Because the autographed is very flexible. Unlike a background graft, there's no need to over think the positioning of the coronaries. I really just place them in the middle of the sinus of al salva unless the native coronaries have any anomalies in terms of their origins at themselves. Mm The hole in the autograph can be kept rather small again because the autographed is quite stretchy and I use a six Oprah lean structure as you can see here to re implant. This is the left main being implanted and then the right will be implanted there after this is the left main button. After implantation on the in the left coronary sinus of the pulmonary autographed. The same thing is done in the right coronary button and you can see that the whole is spoked really in the body of the sinus itself. Um although the coronary always seems to be wanting to sit much higher. But the reality is that the autographed, once the operation is complete will lie, will lie horizontal and that will pull the coronary up so there's no need to overdo implanting the coronary high. And importantly, it allows to trim the pulmonary autographed right at the level of the sign and tubular junction as I'll show you in just a bit. The implantation is pretty similar with the six proteins future no difference there again, this is living tissue on living tissue. They're very him. A static and very flexible structures. You see the small connell branch here close to the austin of the right. These are often present and often sacrificed at the time of surgery with no impact on either ventricular function or in terms of everything in these patients. After we've done this, we move over to the right side and complete pulmonary hama graft implantation. And the two principles for pulmonary home a graft implantation are 12 oversize the home a graph. So we only use home a graph size 28 or higher. Because we do know that some of in some patients there is an inflammatory reaction that that occurs in the first 6 to 12 months after surgery, which can lead to hama graft stenosis, particularly at the super valvular level, by implanting an oversized home A graph. This really mitigates the impact of that from a human dynamic standpoint. And then secondly, we try to avoid any purse stringing again at that distant future line where some of that super valvular stenosis is sometimes observed. Um This is what a home a graft looks like looks like. We now use the secularized hama graphs which have uh significantly reduced that risk of early inflammatory reaction. And early home a graft dysfunction in patients. Um I mark the lateral and medial side so that the home a graft can be implanted in an anatomical position. We transacted right there just before the bifurcation so similar to what we did on the patient side. And then we will start with the distal sertraline and follow with the proximal structure line. So you see the assistant pulls the heart down with the sucker there it creates or it opens that space between the R. V. O. T. And the dystopia. And that makes this distal anastomosis much easier. Also having the clamp high up makes the distal anastomosis and that view much more open than if you calculate lower on the order and the climb then sits in your way as you're doing this anastomosis. Um It's a running five Oprah lean structure which is um interrupted uh 33 spots again to avoid the per stringing effect. Once the distal sertraline is completed, as you can see here, then we move over to the approximate switcher line. Um The main principle, in terms of the proximal sertraline is to avoid avoid the first septal artery. I'm showing it here in this particular case. It was a really good illustration because it was very superficial. And so the main principle is for these futures when you go through the septal muscle there, especially in the first lateral half of that septal portion to take the future is very a partial thickness through that septal muscle, so as to avoid grabbing the first septal artery when doing so. The reality, the reality is that even if the first septal artery were injured at the time of surgery, which is a very rare event. But if it were, it really would not cause as dramatic and impact as the literature would have it. Um I think the early results uh with early failures, we're more due to my cardio protection and other elements than first septal artery injury. We know that now from alcohol septal ablation of the septal arteries, we know that when we come off pump and patients are paste and the septum does not move. This does not prevent patients from having normal or preserved human dynamics. That being said, all efforts are made to avoid injuring that first step to. And as you can see as you move more towards the aortic side on the, on that inter ventricular septum, the futures can be taken deeper because there are no branches that are at risk of being injured. And then this is just a pure continuous future line that completes the pulmonary home a graft. Now we move back to the aortic side to the distal future line, and the main principle is to cut the autographed very short or flush at the signing tubular junction. One of the early mistakes was to leave a lot of pulmonary artery distal to the sign and tubular junction. And that was at risk of dilating once under uh systemic pressures, which would then stretch design and tubular junction and induce aortic regurgitation. So we leave no more than 2 to 3 millimeters above the Commissioners, which will be included in the digital future line. I interpose a background graft a very short background graph between the autographed and the native distal is sending aorta anytime. There is sending aorta exceeds about 36 millimeters in diameter. Or if there's any mismatch between the distal a sending aorta and the pulmonary artery S. T. J. So as to avoid against stretching that sign of tubular junction. And also to make sure that we stabilised that S. T. J. In case the native aorta were to dilate over time. Once again, we cannot overstress the importance of careful commissioners symmetry, not just at the level of the proximal future line, but also at the level of the S. D. J. Making sure that the three commissioners sit at 120 degrees because any asymmetry will cause the commissioner's not to stand straight. And that can also induce prolapse of one of the cast or a. I. So to do so. Before doing the distant future line. You see these three structures that were placed there were placed right above the three commissioners on the pulmonary autographed and then all excess tissue above those will be totally resected, leaving really just uh the sinuses of val salva on the pulmonary autographed side and not leaving any sucre commission ral ph tissue that would be at risk of dilating under systemic pressures. So you see we use these curved scissors which allow us to go circumferential E and respect that entire pulmonary tissue above the com assures. And then what we're left with is really just purely sinuses of val salva. Um in terms of pulmonary tissue on the aortic side. And then here we mark this dacron graft. Is patient specifically had a hemi arch replacement which was performed earlier. And the graft is then marked at three uh symmetrical positions at 37 and 11 o'clock which will correspond to the three commercials on the pulmonary autographed. This is a five running pro lean switcher and you see the switches are passed very carefully through the autographed. That tissue is very thin. Obviously in any of these needle holes can cause a bleeding at the end of the operation. So it's important to really respect the tissue. Follow the needle and um and not and keep the sweltering very tight so that it seemed ecstatic. Now how do we prevent the sinuses of al sada from dilating? We've now spoken about the aortic analysts the sign of tubular junction. Well two things. One is we wrap the native autographed with the patient's own tissue so we always leave the native non coronary sinus completely intact on the outside. We don't split it. And once the operation is finished, as you can see here there's a short interposition graft between the native aorta and the autographed at the bottom here. That native non coronary sinus will be tacked uh along uh the dacron above the distal future line between the autographed and the background. And similarly that lip of the commissioner tissue between the left and right commercials will also be tacked onto that background graft. And that will provide native jacket ng of the autographed along the non coronary sinus along the left right, commit. Sure and uh prevent uh sinus politician. But I would say probably the most important element is early uh and sustained blood pressure control Immediately after the operation and for the first 6 to 12 months after surgery. The reason being, as I mentioned in one of the main principles of this operation, this is a living tissue and therefore it can adapt to new conditions. And we know that the autograph from X plants shows adaptation the tissue itself from a cellular level and an extra cellular matrix level is more akin to aortic tissue than pulmonary tissue late after X plantation. And so what we do is once we take the cross clamp off, we do not allow systolic pressures to exceed about 1 10 millimeters of mercury. And we keep that for the first 6 to 12 months using beta blockers. As first line therapy to decrease DP DT. And what we do is we make sure that we have a remote patient centered blood pressure monitoring system where patients have an app on their smartphones That records their blood pressures on a daily basis and any time it exceeds the desire target of 1 10 of mercury with just the medication accordingly. this is one example of a patient that left the hospital with adequate blood pressure control and as he resumed his activities, you see the blood pressure started rising into the 1 31 40 range. We immediately adjusted his blood pressure medication once, twice and three times until we reached adequate blood pressure control Under 110 of Mercury for the ensuing months. From our experience in about 60% of patients, um all of whom leave the hospital with adequate blood pressure control. Almost two thirds will require at least one blood pressure medication adjustment specifically during the first 2 to 3 weeks after discharge. And on average is about 1.5 times that the patients need to be adjusted. And the last point I will talk about over the next five minutes is how now do we tailor the ross procedure for patients with aortic regurgitation? I mentioned earlier that this was one of the risk factors for higher risk of re operation so we can improve on that. And there are many uh different groups have proposed different approaches to mitigating the risk of autographed allocation and patients who present with aortic regurgitation, one of which is using an inclusion technique within the native aortic root. This is a very reliable and robust approach, But it eliminates a lot of patients from being candidates for the Ross. Because the native aortic uh geometry dictates whether a patient can have a Ross or not. And in some patients, particularly those with unique aspect valves with coronaries that can be placed more at 180° from each other, it can be more challenging. Another approach is to put everything inside a background tube, um that will obviously prevent any sinus salutation. But I think it may not be the best approach because it eliminates the dynamism of the autographed route, which is really the whole rationale behind performing this operation. Our proposed approach is to use rather a an extra aortic annual plastic to support the approximate future line a background graft. As I showed you to support the sign of tubular junction and the native jacket, ng with the native aortic tissue along the non coronary sinus and between the left and right commissars. The aortic cannula plastic is therefore used in all patients who present with ai or patients with mixed essay I with the predominance of aortic regurgitation and patients who have a dilated aortic aneurysms And those who have a mismatch between the aortic and pulmonary analysts of more than two. This is what it looks like technically speaking. Um If we open an aortic root, we place six mattress futures from the inside. We pledge at them. They go at the bottom of the three natures and at the bottom of the three commissioners, ensuring that the one between the right and the nun sits higher up so as to avoid the conduction tissue. But the idea is really to stabilize the basil ring and to sit the autographed at the end within that. And we've shown in previous studies that that is very effective at reducing the size of the annuals and at maintaining it over time. This is what ultimately looks like with the ring sitting on the outside of the or recruit. But step by step after we've dissected all the way around the roots, down to the level of the basal ring. Similar to what one would do with a valve sparing procedure. Um 620 Esteban pledged that futures are placed along the basal ring in the horizontal plane from the inside to the outside. So you see here this one is going right at the bottom of the left, right, commit. Sure. And then this one between the right and the nun. We place it just a little higher so as to avoid the conduction tissue and avoid any need for pacemaker implantation in these patients. And then we use a background tube from which we cut About 3-4 rings, which will then constitute the annual plastic ring, which will sit on the outside. The way we choose the size of that ring is according to the size of the pulmonary analysts. We oversize the ring by about 5-6 mm versus the pulmonary annular diameters, so as to account for the thickness of aortic tissue on both sides. Now the ring is then lowered down after the futures have been placed through the ring and the ring will be tied around a Hager dilator, um which is the same size as the pulmonary analyst diameter size. So you see the ring is sitting on the outside, along the basal ring of the of the heart. And then once the switchers are tired, you see here the annual plastic, you see the and this becomes more circular and it has we have reduced the size of that and it really does not dilate over time. So this is a very robust and stable way to stabilize the aortic aneurysm over time. So briefly this is really these are all the technical points for the step by step ross procedure. And I think that all of these are tailored not just to ensure safety of the operation, but really to try to ensure long term durability of the operation. We have learned many lessons and I think that the results to come will continue to improve over the known literature. And we're continuing to follow our patients systematically to continue to learn lessons and to improve the technique. But I think surgical technique is intimately related to long term durability in the ross. It requires a clear understanding not only of the static but also the dynamic anatomy of the aortic root and how it relates to the pulmonary route. Early adaptation is very important, after the ross, and we have to avoid early dilatation at all costs, and I showed you blood pressure measurement is really key in terms of ensuring that early adaptive remodeling of the pulmonary autographed. And finally, I think a tailored approach can further improve outcomes in patients with aortic regurgitation. Thank you very much for your attention and look forward to your questions.