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The Take Home: ACC Scientific Sessions
Image: Brian Ellis
At the end of March, the American College of Cardiology held its annual Scientific Sessions in Washington, D.C. Cardiology Today’s Intervention was onsite and interviewed several experts on some of most talked-about interventional trials presented. Interviewees included Robert J. Applegate, MD, FSCAI, of Wake Forest School of Medicine in Winston-Salem, N.C.; James B. Hermiller, MD, FACC, of St. Vincent Hospital/The Heart Center of Indiana, Indianapolis; David Kandzari, MD, with Piedmont Heart Institute, Atlanta; Srihari S. Naidu, MD, FSCAI, of Winthrop University Hospital in Long Island, New York; J. P. Reilly, MD, FSCAI, of Ochsner Medical Center in New Orleans; and Robert Vincent, MD, FSCAI, with Children’s Healthcare of Atlanta and Emory University School of Medicine.
CoreValve HIGH RISK
Robert J.
Applegate
Applegate: The CoreValve High Risk study was a comparison of a stent valve (CoreValve, Medtronic) vs. surgical aortic valve replacement in patients with severe aortic stenosis who were at high risk for undergoing surgery. The key finding from this study presented at the ACC Scientific Sessions was that at 1 year, there was a significant decrease in mortality with TAVR (14.2% vs. 19.1%; P for superiority=.04). This finding has great ramifications for TAVR, in general, and for our patients. We also saw that there were some differences within subanalysis of complications, including higher rates of pacemaker implantation and vascular complications in the TAVR arm, and higher rates of bleeding and renal insufficiency in the surgery arm. Importantly, this was the first trial to prospectively evaluate the risk for stroke after surgery or TAVR. This has been an area of potential concern because of the size of the catheters used to introduce these valves, which is larger than what is used for routine diagnostic catheterization and PCI. There was also no difference in the absolute rates of major and all strokes, which differ a little from what we saw in the PARTNER trial.
Based on these results, if you were to pick apart the trial statistics and method, the worst you can say is that TAVR is equivalent to, if not better than, surgery. Whether TAVR is going to become the standard of care for patients with aortic stenosis, in general, is a hotly debated topic. Nevertheless, it is an exciting time for our patients.
CHOICE
Hermiller: The CHOICE trial was a modest-sized study (n=241) that looked at the effect of the CoreValve vs. the Sapien XT (Edwards Lifesciences) valve on the primary endpoint of device success. Based on the aortic insufficiency defined by angiography, device success was significantly less frequent in the CoreValve arm than in the Sapien XT arm (77.5% vs. 95.9%; RR=1.24; 95% CI, 1.12-1.37). My take on this finding is that I’m not sure the results are reflective of what we’re seeing in contemporary practice. The amount of aortic regurgitation after CoreValve implantation was moderate to severe in almost 20% of the patients. If you look in large studies, it’s more like 7% to 10%. That’s was an important question I had with this study. Although the angiography was a core lab-based measurement, most of us see a variability in the way we assess this somewhat qualitative measure. There was some echocardiography and MRI done, although there was no CORE lab adjudication. The third thing that was a bit unusual was almost 6% of the patients needed a second valve, and half the CoreValve patients had balloon valvuloplasty after the transcatheter valve was implanted; both of those are very high compared with what we’re seeing in practice. So it makes one wonder about the results in the CoreValve group, and because of this, I wouldn’t say the study is conclusive in terms of making a definitive statement that we should choose one valve over another.
MELODY TPV
Vincent: The Melody valve (Medtronic) is a transcatheter pulmonary valve used in pediatrics and adult congenital patients. The post-market study presented at the ACC Scientific Sessions was a follow-up to the humanitarian device exemption release of the Melody valve a few years ago. Investigators from 10 centers enrolled 120 patients, 100 of whom had attempted implantation. The success rate was phenomenal. There was only one patient in whom the Melody valve wasn’t implanted due to a complication during the procedure. The 1-year follow-up was excellent. There was acceptable valve function in 96.7% of patients, and although there was no surgical cohort for comparison, we know historically that even with surgically implanted valves, we don’t have 100% acceptable valve function after 6 months or a year. So this study has proven the effectiveness and safety of the Melody valve and the wonderful use of percutaneous valve implantation in children to prolong the requirement to further surgical repair. We know that it is probably a palliative procedure for many children, especially younger ones; however, we can probably extend the time to another valve-in-valve percutaneous procedure or surgical replacement of the conduit to 5, 10 or maybe even 15 to 20 years.
NEXT
David
Kandzari
Kandzari: In the 3,200-patient NEXT study, the 2-year outcomes for a biodegradable polymer biolimus-eluting stent (BP-BES; Nobori, Terumo) vs. a durable polymer everolimus-eluting stent (Xience V, Abbott Vascular/Promus, Boston Scientific) did not demonstrate any significant difference in the primary efficacy (P for noninferiority=.0001) or safety (P for noninferiority=.003) endpoints; in fact, there was almost an identical event rate across all the elements of a composite endpoint. The reasons for this, in part, are because with existing DES today, we are observing the best event outcomes with regard to safety and efficacy that we’ve ever witnessed. This may also importantly represent changes of practice that may be less quantifiable than just the stents themselves. However it may be, it raises the threshold and makes it difficult to illustrate superiority for new DES designs. Nevertheless, even with larger numbers of patients, if the trajectory of events remains the same, it would be difficult to demonstrate differences in this patient population.
ZEUS
J. P. Reilly
Reilly: At the ACC Scientific Sessions, the ZEUS investigators presented the results of their trial, in which they randomly assigned 600 patients 1:1 to an Endeavor zotarolimus-eluting stent (Medtronic) vs. a bare-metal stent. Patients were at an increased risk for bleeding, had a high thrombotic risk, or were at a normal risk for thrombosis or bleeding. Patients were then prescribed dual antiplatelet therapy based on their individual risk. Patients with a high risk for bleeding received just 1 month of therapy, as did patients with the usual risk; however, those at high thrombotic risk had their DAPT tailored to their individual needs. Most received 6 to 12 months of DAPT. There’s been a lot of concern about DES and the risk for prolonged DAPT, as we’ve generally prescribed and mandated 6 or 12 months of therapy for all patients with DES. The ZEUS investigators wanted to examine whether the Endeavor stent would allow them to prescribe a much shorter duration of DAPT, only 30 days. The result of this trial showed that the BMS group had a higher risk for MI (8.1% vs. 2.9%; P<.001), MACE (22.1% vs. 17.5%; P=.011) and stent thrombosis (4.1% vs. 2%; P=.01) than the Endeavor arm. So the conclusion for the ZEUS investigators was that the use of the Endeavor DES could safely allow practitioners to prescribe just 1 month of DAPT. If these results are corroborated, it would be a great benefit to patients at high risk for bleeding or those who need to undergo a planned or elective surgery after their stenting.
CARDIAC TROPONIN T
Srihari S. Naidu
Naidu: An interesting trial looking at troponins in the emergency room was presented at the ACC Scientific Sessions. The study included 330,000 patients from Sweden presenting to the hospital with chest pain. The idea behind the trial was to decipher if patients with a low or undetectable first troponin level were safe to discharge from the hospital. As we all know, these patients are a large proportion of ER admissions. The trial found that a little more than 4% of patients had a troponin level of less than 5, which was considered undetectable. They then tracked these patients and found that within 30 days there was only a small incidence of MI; roughly 40 of these 9,000 patients had an MI. They then evaluated whether any of these patients had ECG changes, and the vast majority who had an MI did have ECG changes, leaving only 15 of the 9,000 patients who ultimately had an MI within 30 days despite having a normal ECG and normal troponin. It’s an interesting trial because it answers, to some extent, the question of what to do with the large amount of patients coming into the ER with chest pain who have a normal ECG, and whether one single normal troponin on top of this would be enough to say they are sufficiently low risk to discharge. In the United States, we typically do two troponins because it often takes a few hours for the first one to be elevated, and we have generally not been comfortable with missing any MIs, even at the very low rate seen in this trial. Ultimately, it was a good trial and adds food for thought on where we should go in this country with troponins, namely what threshold of subsequent risk is sufficient to warrant early discharge. Importantly, it might bring up differences between how we treat patients in this country and elsewhere, and the reasons behind such differences.