Dr Charanjit (Chet) Rihal: Hi, I'm Dr Chet Rihal, chair of the division of cardiovascular diseases at Mayo Clinic Rochester. Welcome to Mayo Clinic's collaboration with theheart.org on Medscape. Today, we're going to have an exciting panel discussion about novel options for revascularization for multivessel coronary artery disease. Joining me today are my colleagues, Dr Rajiv Gulati, interventional cardiologist here at Mayo. Rajiv, welcome.
Dr Rajiv Gulati: Thank you.
Dr Rihal: And Dr Alberto Pochettino, my colleague from the division of cardiovascular surgery here at Mayo. Alberto, welcome.
Dr Alberto Pochettino: Thank you.
Recent Advances in Revascularization
Dr Rihal: Alberto, let me start with you. What would you say are the most important recent advances in coronary revascularization?
Dr Pochettino: I think one of the most important transitions—it's not necessarily new—is the use of arterial conduits more frequently. The tradition has been, for many years, to use it to the left anterior descending artery (LAD) only, and it has been shown that use of multiple arterial conduits to other territory does have a benefit. That has been the transition I've seen throughout the cardiovascular practice.
Dr Rihal: How often is total arterial revascularization being done now?
Dr Pochettino: Well, if you look at the national trend it is still a minority. If you exclude left internal mammary artery (LIMA) to the LAD, which is done routinely in most places, any additional arterial conduit, using the [Society of Thoracic Surgeons] STS database as a measure, it is still in the 10% to 15% rate.[1,2]So it's still very low. The penetrance to the general practice of cardiac surgeons has not been as good as it should be.
Dr Rihal: Now what's the holdup? Are pump times longer? Is it more technically challenging?
Dr Pochettino: It's a good question, and I think there are at least two factors. The first one—it is a real issue—is that multiple arterial conduit is more difficult to do. In the real world, cardiac surgeons don't like to make their life more difficult than they have to.
The second one is, we as cardiac surgeons, like everybody else, are being judged on our results. Most of the focus of the results is short term: 30-day mortality, infection rate, hospital stay. Clearly, the introduction of bilateral mammary increases all of those risk factors. So there is a disincentive on the part of the regulators, if you want to look at it that way. If your risk of sternal infection goes from 1% to 2%—which it does when you use bilateral internal mammary in a nondiabetic—that is a strike against you. As a surgeon, you don't want that strike. If you use it bilateral mammary in a diabetic, it may go as high as 10%. Which surgeon wants to have their infection rate at 10%?
If you look at long-term results, clearly, that's where the benefit is. But we are judged on short-term results. There is incentive for not doing something that, short term, increases your risk and lowers your result. I think that's a big drive that has been very difficult for cardiac surgeons, especially in a small institution, to get over.
Dr Rihal: This is a very important observation. Rajiv, in the field of interventional cardiology, what would you say have been the most important advances in multivessel revascularization in recent years?
Dr Gulati: I think, in recent times, probably three things have changed or continued to change. The change in drug-eluting stents from the first generation to the second generation, I think, has been a real advance. We weren't sure at first. We thought there was going to be an incremental change, but now with data, we're recognizing that the first-generation drug-eluting stents were a problem. They were the ones plagued with risk of late and very late stent thrombosis, [an observation] we are all now very in tune with. The transition to second-generation stents has really been a paradigm shift, I would say. We now know, with data, that the second-generation drug-eluting stents have a much better safety profile. The rate of late stent thrombosis of these stents is lower than bare-metal stents. That's a big shift.And the rate of very late stent thrombosis doesn't seem to be a concern with the second-generation drug-eluting stents.
The second thing is a growing understanding of the role of clinical characteristics and patient values and preferences in choice of revascularization. We are seeing a lot more elderly patients now with complex calcific disease but also with major comorbidities that may influence the choice of revascularization. For many patients, stroke is a concern—as is procedure-related stroke and time-out-of-hospital recovery time—and these are the factors that are often influencing our decision to go with percutaneous coronary intervention [PCI], perhaps more than bypass, in some circumstances.
The third is a move in the anatomic subsets that we're now more comfortable dealing with—in PCI, I would say, left main. Increasingly now, there are data supporting PCI in left main[3,4]in certain anatomic subsets. And now, perhaps most recently, is chronic total occlusion.[5]We have newer techniques learned from overseas and finessed in the US. Our rates of success in getting across and successful results in chronic total occlusions are much higher than before, and our ability to do complete revascularization has changed significantly over the past 2 years and will continue to improve over the next few years.
Second-Generation DES vs CABG
Dr Rihal: Rajiv, you talked about the second-generation stents and how they are much better than the first-generation drug-eluting stents, which I think we would all concur with. Do you think they're quite ready yet to take on bypass surgery head-to-head? We do have some new trials addressing that question. I'd like to ask both of you what you think of that?
Dr Gulati: Yes, it's interesting, philosophically, we see a trial come out comparing PCI with bypass surgery, and then we respond, "Well, gosh, we have better stents than we did back in the day when we did that trial." It seems to be an ongoing thing, and it will continue to be ongoing.
We do have some recent studies—one large registry comparison between two registries[6]and also one randomized trial from East Asia comparing the second-generation drug-eluting stents in multivessel disease with bypass grafting.[7] To be fair, bypass grafting still came out on top in terms of the composite end point. So I don't think we're able to say that the second-generation drug-eluting stents have completely changed the way we approach multivessel disease.
Dr Rihal: Let me turn now to you, Alberto. Now that you've heard this discussion about how every generation, these stents are getting better and better, and the differences and outcomes between multivessel bypass surgery and multivessel PCI are narrowing. What are the key clinical and anatomic factors that you use in counseling patients as to which technique may be best?
Dr Pochettino: When I think of using bypass surgery in a patient, I think of long-term benefit because, short term, it's pretty clear that a good drug-eluting stent can do as well as surgery. So, I talk to the patient. A young individual who may have a risky interventional bifurcation lesion or something like that, where I could offer a better long-term result with, of course, the price of surgery, especially if I have available arterial conduits, then that's the way I'm thinking.
[Conversely,] if the person would not get that benefit—say, an elderly individual who has all sorts of comorbidities—I would only address that patient surgically if there is such technical difficulty in addressing it with a drug-eluting stent or with another interventional technique.
So, the first class of patients are young individuals who have a good long-term lifestyle benefit as well as survival benefit. And then, of course, there are technical issues related to which targets. Can we get them in one way or the other? What's the risk of one vs the other? So those are technical issues that we often have to talk about and what makes most sense.
Dr Rihal: Thank you. Rajiv, what are the technical and clinical characteristics that you use in counseling patients?
Dr Gulati: I think, increasingly, clinical features, so diabetes. Every trial of diabetes in multivessel disease favors bypass grafting, and the recent FREEDOM trial supports that.[8]Increasingly, it is hard to make an argument for PCI in multivessel disease in a diabetic who is otherwise doing well, even straightforward PCI. But the mortality benefit with bypass grafting is really quite clear there. I think one has to be strongly persuaded to do PCI in that population.
[As for] the extent of disease, in every trial, patients with diffuse multivessel disease do not do well with PCI. Patients come back with myocardial infarction [MI], mortality concerns, repeat revascularization. Diffuse multivessel disease, I think, is the domain of the surgeons, and we've learned a lot from the older SYNTAX trial[9]in that regard. The patients with the high SYNTAX scores, complex diffuse disease, do better with surgery.
Where Does the Hybrid Approach Fit In
Dr Rihal: As patients are getting older with more complicated disease, what is the role of hybrid approaches due to this complex disease? Alberto, do you see any role for this, or is it just too complicated logistically?
Dr Pochettino: I think it has a role, and the role is in the complex patient with multiple difficult targets as well as lack of conduits. It is not unusual for a 70- or 80-year-old to have very poor veins. You have only two mammaries, and the question is: How are you going to use both mammaries, or maybe just one? The radials are typically not usable. There is vascular disease that, late in life, affects the radial. You're limited to what you can offer that would work long term.
You do the best you can with what you have. Then, having other techniques available to address some of the other territories makes sense in that setting. In a young patient who has available conduits that would benefit them long term (that you know you're going to rely on and they're going to do well), then I would say the pendulum is more on the surgical side. But those patients are not as many as we would like. A lot of the patients are in that sort of complex, no-conduit or marginal-conduit situation, with a lot of disease. So that's where the hybrid approach would make sense.
Dr Rihal: I think we're all in agreement that patients with a large burden of atherosclerotic disease—severe three-vessel disease or diffuse disease, for example—are best served with bypass surgery. But, Rajiv, one of the advances and observations in recent years has been in patients with isolated left main disease who appear to do equally well with PCI. Is that because they don't have as much atherosclerosis overall? And what do you think is the role of left main PCI now?
Dr Gulati: Yes, I suspect that's the most likely mechanistic explanation. An isolated left main lesion, with not much atheroma elsewhere, can be the most straightforward of PCIs. It can be a 2-minute PCI. We can infer from the benefits of surgery—which are always fewer myocardial infarctions and fewer repeat revascularizations—that if you don't have that atheroma burden to begin with, you're not going to achieve the benefit from surgery of fewer MIs and fewer revascularization repeats. I think PCI probably is favorable for left main or at least as good as coronary artery bypass grafting [CABG] in the absence of severe atheroma elsewhere.
Dr Rihal: From carefully selected left mains?
Dr Gulati: From carefully selected left main, anatomic left main disease, and lack of severe diffuse disease elsewhere.
Dr Rihal: Alberto, what do you think of that?
Dr Pochettino: I think it's very interesting that isolated left main disease does well with an interventional approach. To me, it makes me think that a lot of isolated left main disease is ultimately an extension of aortic atherosclerotic, not coronary atherosclerotic, and the perfect example would be Takayasu arteritis. I've seen a number of patients, I've operated on a few, where their only coronary disease is right at the ostium of the right and the left. Beyond that, there is nothing that is abnormal.
Obviously, that's the extreme, but there is such an entity as aortic disease and certainly, the left main relies on the aorta as a significant component of what its substrate is. In that setting, it makes sense that it would behave differently from your standard coronary disease where disease is much further downstream.
Off-Pump Bypass Out of Fashion?
Dr Rihal: Let me ask you another technical-type question. What's the role of off-pump bypass surgery? A lot of us are concerned that some of the morbidity associated with bypass surgery is actually due to the pump. So, what about eliminating the pump? What's your feeling on that? What's the roll of off-pump surgery?
Dr Pochettino: It's an interesting question on a personal level. When I started my practice in the late 90s, as a young surgeon—this was the beginning of off-pump—I embraced the off-pump technology. In fact, I was the first surgeon, at the time I was in Philadelphia, doing off-pump CABG in Philadelphia, and I developed quite a large practice.
Eventually, I realized that I was mostly treating myself and my referrals. When I looked at my results—I did it for about 5 years and then retrospectively looked at my results—they were really no different compared with on-pump, in terms of length of stay, perioperative events, neurologic events.
It almost became an inside argument among surgeons and cardiologists. The patient was kind of an innocent bystander who was sort of allowing us to do our thing, as it were. I came to a personal realization that my priority is to do the best job that would get the best long-term result. There is no question in my mind, having done many hundreds of off-pump CABGs, that the technical ability of doing a perfect anastomosis with a still heart is better. There's no doubt in my mind.
Ultimately, I changed my practice. The priority is, in my mind, especially in the world of drug-eluting stents (these are as good as they are going to get) to get the perfect anastomosis and get a perfect result, technically. Now, there is a role for off-pump CABG in patients who have heavily calcified aorta, who have very severe cerebrovascular disease. So, I still find a place for that technique in the very advanced high-risk patient for neurologic events. So I think that's the role that I still accept. But in patients who have your average run-of-the-mill cerebrovascular risk—we all have some risk—my priority is to get the perfect job on a technical anastomosis, and I think you can do a better job with a still heart.
That's my personal approach. If you look at the STS database, there was an early enthusiasm for the technique that has sort of plateaued.[10] If you look across the country, there haven't been more than 15% of the CABGs done that have been at that level. Essentially, there are surgeons who learn that technique. They are comfortable and they do it, while the rest of them don't.
So that's the way it's turned out. Personally, I think if that's what you do and that's your routine, then you should do it that way because you're going to do it poorly in a different way. You should not alternate it. That doesn't make sense, except for that high-risk population.And that's my personal experience over a couple of decades.
Dr Rihal: I think that's a great commonsense approach to answer to that question. Rajiv, as bypass surgery becomes less invasive, PCI appears to be getting more invasive. What's the role, in your practice, of supported PCI? I know in the cath lab, you've got lots of different support devices from balloon pumps, [extracorporeal membrane oxygenation] ECMO, tandem hearts, etc. What is the role of these in high-risk PCI?
Dr Gulati: On the one hand, having PCI we've got true transition to the radial approach and think we're minimally invasive, but you're absolutely right. In the complex, high-risk, particularly elderly patients with poor LV function, we're now increasingly using periprocedural support with large-bore transfemoral sheaths. The role, I think, still remains to be determined.
We're learning, increasingly, that there's probably less of a role for the old-fashioned balloon pump in terms of support during a PCI. The hemodynamics don't really fit, with particular benefit; the clinical outcomes are either equivalent or not as good.[11,12] They're certainly not better with balloon-pump–supported PCI. The real question is whether the more sophisticated devices are going to provide benefit. There's the Impella pump device. There are newer heart-rate devices, extracorporeal membrane oxygenation, tandem heart, as you say. In certain circumstances—anecdotally, I can say, unquestionably—patients have done better with them who would have done poorly without them, anecdotally. But the aggregate data, I think it remains to be seen.
One of the problems is, how do you randomize patients who you perceive to be at such high risk that you want to put in a device? Do you say, "Gosh, can I say there's equipoise there or randomize?" Many trials have been done when the patients have not been so high risk. I don't know if we'll ever get a randomized trial in the old-fashioned sense that tells us exactly what to do, but I do believe there is a role, an increasing role, for periprocedural support.
Dr Rihal: Thank you. Joining me today have been Dr Alberto Pochettino, my colleague from cardiovascular surgery, and Dr Rajiv Gulati, my colleague from interventional cardiology, both here at Mayo Clinic. It's been a fascinating discussion.
To sum up, we talked about multivessel revascularization and recent advances. Both of my colleagues pointed out the critical role of angiographic, anatomic, and clinical characteristics in helping guide revascularization choices, particularly the extent and diffuse nature of coronary disease, in the presence or absence of diabetes mellitus, as the data all point and continue to point to the superiority of bypass surgery among diabetic patients and those with diffuse three-vessel coronary disease.
Dr Gulati then pointed out the increasing role and the favorable data supporting PCI for isolated left main disease—a procedure, I believe, that is going to become increasingly commonplace here in the United States. Dr Pochettino also talked about the role of off-pump bypass surgery and made some very cogent points about attaining the perfect anastomosis for the best long-term results. And finally, Dr Gulati talked about the role of mechanical circulatory support for high-risk PCI, a subset that's growing and will continue to grow as our patients get older and the LV functions get poorer. I hope this discussion was as enjoyable for you as it was for me. So, again, thank you, Alberto, thank you, Rajiv, and thank you all for tuning in today.
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Mayo Clinic
Cite this: Rajiv Gulati, Alberto Pochettino, Charanjit Rihal. Multivessel Revascularization: Still the Surgeons' Domain? - Medscape - Apr 22, 2016.
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