P Gabriel Steg, MD; Jean-Philippe Collet, MD, PhD

Disclosures

June 30, 2016

Editor's Note: The following is an edited translation of the transcript from a video discussion on Medscape France that focused on the Congress of the European Association of Percutaneous Cardiovascular Interventions (EuroPCR) 2016 conference.

Gabriel Steg, MD: I'm Gabriel Steg from the Bichat Hospital in Paris, and I'm pleased to have with me today Jean-Philippe Collet from the Pitié-Salpêtrière Hospital for a discussion of EuroPCR 2016. EuroPCR is the main European interventional cardiology conference, basically the counterpart of TCT in the United States. Obviously, we won't be able to give you a complete report on the conference, but there are a few major emerging trends and some news that grabbed our attention that we would like to tell you about. Jean-Philippe Collet, what has stood out or impressed you?

Prof Collet: As for the hot lines, two things are particularly noteworthy. One is Philip Urban's study, the LEADERS FREE ACS trial[1] which compared a drug-coated polymer-free stent (BioFreedom, Biosensors) with bare-metal stents. This subanalysis included ACS patients at high risk of bleeding, and it used a very short course of dual antiplatelet therapy (1 month). The polymer-free stent was beneficial in this group of patients with ACS, who accounted for over 25% of the main trial population.[2] There was a trend toward a reduction in mortality, which confirms that the technology can also be used in the highest-risk patients who will not necessarily receive a prolonged course of dual antiplatelet therapy. I think this underscores the superiority of drug-coated stents.

Prof Steg: It's been said that there are no longer any indications for bare-metal stents.

Prof Collet: Exactly, especially in patients in whom they used to be implanted.

Prof Steg: Which is paradoxical. We didn't dare implant drug-eluting stents in patients at high bleeding risk, and now they seem to be the ones who should be getting the latest generations of drug-eluting stents.

Prof Collet: That's quite right. The trend is growing, and I think it's going to become standard practice.

Transcatheter Aortic Valve Implantation/Replacement (TAVI/TAVR)

Prof Collet: The second noteworthy topic is structural valves. The subject of the "Great Debate" at EuroPCR was extending the indications for transcatheter aortic-valve implantation (TAVI) to lower-risk patients. We have data on TAVI in intermediate-risk patients,[3] but then there are low-risk patients—that is, patients with an STS score of less than 4, who are good candidates for conventional surgery but who are also good candidates for a potential TAVI. Given that they are younger patients, this raises the question of the durability of these bioprostheses.

Prof Steg: Because previously, patients would die before their valves did, but if we move to lower-risk patients, they will probably outlive them.

Prof Collet: That's right. Furthermore, the higher-risk patients died mainly from other causes. We clearly saw that in the TAVI series such as PARTNER-1[4] where nearly 70% of the deaths were due to noncardiovascular causes. We see now that the situation can change and the durability of these bioprostheses is a real issue. We don't have a lot of long-term data.

Prof Steg: That's right. There was a series presented with 10-year data[5] that are rather reassuring. It was the series with the longest-term results.

Prof Collet: It's rather reassuring. We have to decide how to evaluate durability. One way to do this is to look at the gradients: in nearly 40% of patients, there is an increase in the gradient over time, which can be a sign of deterioration or thrombosis. The best way to assess that is with computed tomography [CT]. I think that we should start evaluating our patients better, in particular, with 4D computed tomography, to see exactly what's going on. Is it bioprosthesis deterioration? Is it pannus? Or is it thrombus? We know that the therapeutic approach will differ accordingly.

Prof Steg: We're still in the dark about the post-TAVI prosthetic thromboses that have been reported.[6] These thromboses are asymptomatic in the vast majority of cases, and we still don't know what the mechanism is or their consequences.

Prof Collet: The consequences probably aren't all that serious; we're still talking about a small series of a few dozen patients. What we do know is that anticoagulation therapy restored leaflet motion. It raises the question: should anticoagulation therapy be the default treatment in these patients, given that it wasn't standard for surgical bioprostheses, unless the patient had an indication, such as atrial fibrillation?

Prof Steg: You're conducting a study in this area with anticoagulation therapy, which should give us some valuable information, since there will be an anticoagulant group and a nonanticoagulant group.

Prof Collet: That's right. It's the ATLANTIS study. It's starting very soon and will involve a mix of patients: low risk, high risk, and those with or without an indication for anticoagulation (with or without an antiplatelet agent). The issue is especially relevant to TAVI, because unlike with surgical bioprostheses, the native valve remains in place. That can be prothrombogenic. There are a lot of tissue factors and a sort of mesh around it that could promote thrombosis.

Prof Steg: Let's continue on the subject of TAVI. There are those who propose prophylactic therapy in asymptomatic individuals. Are we going to consider performing TAVI in people who have no symptoms but who have severe aortic stenosis? The analogy that's often made is that of mitral insufficiency, where prophylactic surgery is necessary to prevent degradation of left ventricular function. If we treat these patients earlier, we would achieve better outcomes. On the other hand, the prognosis for patients with severe calcified aortic stenosis is excellent. There is the temptation, which I will refer to as the temptation to deviate. I think it's still rather provocative.

Prof Collet: It is provocative. There will have to be studies done in asymptomatic patients. I agree that there is a comparison to mitral disease, but there's also a comparison to coronary artery disease in the asymptomatic patient. We're having difficulty demonstrating benefits for percutaneous coronary intervention in asymptomatic patients. TAVI interventions are not benign. Even though the risk of complications is low, implanting a device in an aortic position is not without consequences in terms of the risk of stroke or thrombosis. This is an issue to be watched.

Prof Steg: With regard to patients with coronary artery disease, we've talked about the advances and the dramatic results that continue to be achieved with the latest generations of drug-eluting stents. We've seen a proliferation of data on bioresorbable stents or bioresorbable scaffolds, but once again, these are small series with short follow-up. We've seen very little randomized controlled trial data. Another area experiencing an incredible explosion in equipment and techniques is PCI for chronic total occlusions, or CTOs. What was previously a fairly esoteric field that interested the CTO clubs, a few fanatics, if I can call them that, has now become a veritable passion.

Prof Collet: That's partly due to advances in equipment because manufacturers often anticipate our needs. A proctoring system has been put in place and there are now highly educational CTO programs, so more operators are learning to do these procedures. With the great strides in equipment, and now that nearly 80% of cases use an antegrade approach, there are fewer risks. Not all patients are candidates for the retrograde approach, and the subintimal approach is also developing because of the availability of dedicated equipment. I think we're witnessing a technological revolution.

That said, some aspects of the procedure have become very complex. There's also a piece missing from the puzzle—namely, long-term outcomes data. It's basically the treatment of stable coronary artery disease. Are we successfully improving the clinical course of these patients, who, in most cases, are also symptomatic? I think we know that there are benefits in terms of quality of life. But what benefits are we achieving in terms of survival? That's the question.

Prof Steg: The paradox is that we've learned to perform a complicated procedure but aren't yet sure that it serves some purpose.

Prof Collet: We need long-term data. We've seen this with angioplasty in stable coronary artery disease. We need to show that there's a mortality benefit with the new technologies in patients considered at medium risk. It will take practice, and I think we're going to succeed.

Prof Steg: I think there should be a randomized, prospective trial comparing medical treatment and angioplasty in patients with CTOs.

Prof Collet: Such a study would settle the issue. We need data like that for practice guidelines and heart-team discussions.

Prof Steg: One last topic that's all the buzz right now is invasive and noninvasive coronary imaging. We have an invasive diagnostic imaging arsenal, with echocardiography, virtual histology intravascular ultrasound, optical coherence tomography, and near-infrared spectroscopy. Now we're witnessing the development of incredible noninvasive tools with practically the same technologies and practically the same quality of plaque images and evaluations. They are very impressive both for imaging the coronary arteries and for image reconstruction and merging for structural elements. The advances in imaging for interventional cardiology discussed at this conference are quite amazing.

Prof Collet: Absolutely. Computed tomography can be used to determine the fractional flow reserve. We can use algorithms to do 4D CT to reconstruct flows, something that we were able to do with MRI. This is going to improve the assessment of stenoses with CT scans. The second thing you mentioned was image merging. The interventional cardiologist who does structural heart now visualizes more from a somewhat surgical perspective. Previously we weren't trained to do this. When we work on mitral valves, it's not angiography that guides us, but rather 3D echo.

Prof Steg: Interventional cardiologists will also have to start using echocardiography.

Prof Collet: We're actually going to become inseparable from the echocardiographer. The echocardiographer is going to help select patients and play an active role in interventions.

Prof Steg: This has been a good 10-minute partial overview of a very big conference. It's an excellent conference, both in terms of education and scientific news. I hope to see you at the 2017 edition.

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