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The Take Home: EuroPCR
EuroPCR, held in Paris from May 16 to May 19, featured numerous presentations highlighting the latest research in interventional cardiology. Cardiology Today’s Intervention spoke to several presenters and attendees for their takes on the proceedings, including Editorial Board members Ted E. Feldman, MD, from Evanston Hospital, NorthShore University HealthSystem, Illinois, David J. Moliterno, MD, from the University of Kentucky, and Matthew J. Price, MD, from Scripps Clinic, La Jolla, California.
REPRISE III
Feldman: This was a trial to evaluate the safety and effectiveness of the repositionable Lotus valve platform (Boston Scientific) in 912 patients with severe aortic stenosis at extreme or high operative risk, with the aim of obtaining FDA approval. With this trial, we have the first direct head-to-head large-scale comparison of contemporary transcatheter aortic valve replacement devices.
For the primary safety endpoint, a composite of all-cause mortality, stroke, major bleeding events, acute kidney injury and major vascular complications at 30 days, the Lotus valve (Boston Scientific) showed noninferiority to the comparator self-expanding CoreValve device (Lotus, 20.3%; CoreValve, 17.2%; P for noninferiority = .003). The primary effectiveness endpoint, a composite of all-cause mortality, disabling stroke and moderate or greater paravalvular leak at 1 year, showed superiority to the CoreValve self-expanding stent (16.7% vs. 29%; P < .001). So, the primary endpoint data were very favorable.
We demonstrated that there’s another TAVR platform that has some clear benefits for patients: the virtual elimination of moderate or severe paravalvular leak as a limitation, and on the obverse, the finding that paravalvular leak in none or trace grade was present in over 85% of patients. This is very different than any of the existing TAVR devices in practice. We hope these strengths are going to be available in clinical practice.
Another distinguishing element of the repositionable valve system is the valve begins to function early during the deployment procedure, so that the need for rapid pacing or the presence of hemodynamic compromise during the deployment is rare. This makes the procedure easier for both physician and patient. And then the fact that the valve can be completely retrieved from its final locked position if need be, or repositioned, is unique. The trial finding that illustrates that is the absence of the need for a second valve during the index procedure, which is an infrequent but important problem with some of the other devices. Other advantages seen were the lack of paravalvular leak, ease of use and retrievability and repositionability.
One of the limitations of the first-generation Lotus system is a relatively high need for new permanent pacemaker implants (35.5% vs. 19.6% for CoreValve; P < .001). We saw in this trial numbers that were similar to our prior experience with this first-generation device. And it’s important to note that permanent pacemaker implants in high-risk patients such as were included in this trial have not had an impact on survival. But nonetheless, it’s an important outcome of the trial, and we’re very focused on improving this result.
The results in some individual site experiences have been much better than this due to using implant techniques aimed at keeping the valve system from interacting with the left ventricular outflow tract. There is a next-generation system that shortens from the top down in comparison to this first-generation system, which shortens from both sides toward the middle. So, shortening from both sides toward the middle causes a lot of interaction with the LV outflow tract. The top-down shortening minimizes this and the earliest results we have with the next-generation deployment system showed a hospital discharge rate of new pacemakers under 20%. This is an important part of the development of the technology, and we hope this will ultimately be the platform that’s initially approved in the United States.
ARTE
Moliterno: In brief, 222 patients that were allocated to receive either aspirin alone or aspirin plus clopidogrel after TAVR, and after a number of months of trying to enroll patients — the researchers were shooting for 300 — they decided to stop the study once reaching 222.
One of the first things the researchers found is that it’s difficult to enroll these patients in randomized studies at this point. That’s going to be one of the challenges for small, individual niche questions that people are trying to answer. Obviously, if it’s a new device, the companies that are developing the new device are going to have to come up with the funds for the research, but it’s a challenge if we’re trying to answer a question that doesn’t potentially have a lot of financial implications. Whenever we want to study aspirin, who wants to pay for it?
What they were able to show is that the events for the aspirin-alone group were not higher than the dual antiplatelet therapy group, which is a good thing, but the conundrum is that the sample size is so small that it probably wasn’t adequately powered. The rate of major or life-threatening bleeding, MI, death and ischemic stroke or transient ischemic attack was 15.3% in the DAPT group and 7.2% in the aspirin group (OR = 2.31; 95% CI, 0.95-5.62). Even with that powering, it looked numerically like the DAPT group had a higher event rate, which doesn’t always make sense to us. That’s why I can’t strongly endorse saying, “This is it. This is the answer. Now we can switch to aspirin monotherapy.”
The bleeding results were encouraging. There was statistically less major life-threatening bleeding with the aspirin alone (3.6% vs. 10.8%; OR = 3.22; 95% CI, 1.01-10.34), probably largely related to vascular access site. The reduction was largely in the first 1 or 2 days, but that all the other events, the ischemic events, be it death, MI or stroke were numerically higher in the DAPT group is encouraging for aspirin monotherapy, though again they were all similar with regard to the statistical analysis.
For those patients in whom we’re concerned about bleeding, especially periprocedural bleeding, we don’t need to preload them with clopidogrel and can probably treat them with aspirin alone. Larger-scale studies will need to be done to be certain of that, but for now, we have some comfort.
ACIST-FFR
Price: There are currently two commercially available ways to measure fractional flow reserve: the standard pressure wires and, more recently, a pressure-monitoring microcatheter (Navvus, Acist Medical Systems).
FR has been shown to improve outcomes and costs compared with the angiography-guided approach, but the uptake and use of FFR has lagged behind the robustness of the supporting data.
The advantage of the pressure-monitoring microcatheter (Navvus, Acist Medical Systems) is that it is very convenient, because the operator can advance this catheter over their own favorite coronary workhorse wire, rather than having to use a pressure wire that does not have the same characteristics or robustness of the standard coronary wire. However, in theory, the catheter itself may interfere with the coronary blood flow and therefore influence the measured FFR.
There are some unanswered questions about the microcatheterization approach. That is, there could be a potential disadvantage in that it has a larger profile than the pressure wire that may influence coronary dynamics and influence the FFR itself. The influence on hemodynamics may vary based on diameter, lesion length and lesion and vessel characteristics. The accuracy of the microcatheter had not been compared to the pressure wire in a large, prospective, multicenter study across a spectrum of vessel and lesion characteristics, so that’s what we decided to address in this trial of 169 patients.
We found that the pressure monitoring microcatheter provided a modestly low FFR value compared to the traditional pressure wire (mean difference, –0.022; 95% CI, –0.029 to –0.015) and the strongest predictor of there being a difference between the two was the physiological severity of the lesion. So, the lower the FFR, the greater the differences would be. Importantly, that means the clinical impact of the difference should be minimal across most measurements, although the operator should incorporate potential differences into their clinical decision-making Therefore, the technology is a great asset for the operator who wants to perform FFR in a convenient fashion, and allows FFR to be more broadly used.
RESOLUTE ONYX 2.0
Price: This study evaluated the performance of a zotarolimus-eluting stent designed to treat CAD in very small coronary vessels (Resolute Onyx, Medtronic) in 101 patients with CAD and vessel diameter < 2.25 mm. Up until now, we didn’t have much data regarding clinical outcomes after stenting of lesions with really small diameters.
There are not great options right now for these very small lesions, and PCI may produce bad outcomes because the vessel being so small may mean higher restenosis rates. These vessels are often also too small for CABG, so then we have to try medical therapy or other options, which may not be optimal.
The device met (Resolute Onyx, Medtronic) its performance goal. At 1 year, the rate of TLF was 5% with an upper bound of the 95% CI of 10.2%, beating the performance goal of 19% (P .001). Target lesion revascularization at 12 months was only 2%. There were also no deaths or cases of stent thrombosis.
Considering that we enrolled lesions in such extremely small vessels in this trial, the success rates were terrific. This new stent really meets an unmet clinical need for operators and patients.
Moliterno: This is the smallest DES we have. What’s impressive about these results is that nearly half the population had diabetes, yet target lesion success at 12 months was 95% among patients with a 2-mm vessel. This is phenomenal.
We have 2.25-mm stents that we could use in these patients, but they’re less attractive because there is risk for damage to the artery.
As opposed to using balloon angioplasty, a bare-metal stent or — someday in the United States — a drug-eluting balloon, this DES allows us to treat the smallest vessels yet, particularly in higher-risk cohorts such as diabetics, with a very high success rate.
AKI-MATRIX
Moliterno: In this study, the researchers looked at 8,404 patients undergoing PCI who were having radial vs. femoral access with particular interest in development of acute kidney injury. Those patients, probably for reasons related to contrast and/or embolization, had better outcomes when the access was by the radial artery. Acute kidney injury occurred in 634 patients (15.4%) with radial access and 712 patients (17.4%) with femoral access (OR = 0.87; 95% CI, 0.77-0.98). There was a greater than 25% increase in serum creatinine in 633 patients (15.4%) with radial access and 710 patients (17.3%) with femoral access (OR = 0.87; 95% CI, 0.77-0.98). A greater than 0.5 mg/dL absolute serum creatinine increase occurred in 175 patients (4.3%) from the radial access group vs. 223 patients (5.4%) in the femoral access group (OR = 0.77; 95% CI, 0.63-0.95).
The issue comes up in a small subset of patients with a concern for acute kidney injury. In those cases, we try to minimize contrast and optimize the patients’ intravascular volume as best as possible, but this was a slightly different take on that: not passing catheters across the renal arteries, per se, but just using the radial access to avoid that.
The results have some implications for clinical practice, particularly in the U.S., because we’re still slightly behind the rest of the world with regard to radial artery access.
Disclosure: Feldman reports consulting for and receiving institutional research grants from Abbott, Boston Scientific and Edwards Lifesciences. Moliterno reports no relevant financial disclosures. Price reports receiving consultant and speaker fees from Acist Medical, Medtronic and St. Jude Medical and consultant fees from Boston Scientific.