Three-year results from the Evolut trial seem to provide more reassurance on the use of transcatheter aortic valve replacement (TAVR) in low-surgical-risk patients.

The 3-year results show that low-surgical-risk patients undergoing aortic valve replacement continue to show lower rates of all-cause mortality and disabling stroke with TAVR compared with surgery.

The rates of all-cause mortality or disabling stroke (the primary endpoint) at 3 years were 7.4% with TAVR and 10.4% with surgery.

Rates of new pacemaker implantation continued to be higher after TAVR and the frequency of new onset atrial fibrillation was more common after surgery.

“At 3 years, the rate of all-cause mortality or disabling stroke after TAVR with the Evolut valve compared very favorably to surgery. The absolute difference between treatment arms remained consistent with a 30% relative reduction in the hazard of death or disabling stroke, with a P value that just missed statistical significance,” said Evolut investigator John Forrest, MD, Yale University School of Medicine, New Haven, Connecticut.

“The Kaplan-Meier curves show what we’ve come to expect — an early separation of the curves — but what’s unique here, and seen for the first time, is that the early separation is maintained at year 1, and year 2, and between years 2 and 3 the curve didn’t start to come together, but if anything separated a little,” Forrest commented. 

“Both components of the primary endpoint — all cause mortality and disabling stroke — numerically favor TAVR. The separation of the curves for stroke are maintained, and if anything, we see a further slight separation of the curves as we go forward out to 3 years in terms of all-cause mortality,” he added.  

Forrest presented the 3-year results from the Evolut trial this past weekend at the American College of Cardiology (ACC) Scientific Session/World Congress of Cardiology (WCC) 2023. They were simultaneously published online in the Journal of the American College of Cardiology.

Forrest also reported that TAVR patients continued to have better valve hemodynamics at 3 years and very low rates of valve thrombosis; moreover, rates of moderate or greater paravalvular regurgitation and paravalvular leak (factors that can affect valve durability) were also low, although mild paravalvular regurgitation was higher with TAVR.

“In these low-risk patients the durability of the valve is going to be critically important,” Forrest commented. “The excellent valve performance and durable outcomes out to 3 years in low-risk patients affirms the role of TAVR in this population,” he concluded.

On how these results may affect clinical practice, Forrest said: “I think in the US these results reaffirm what we are doing. It gives us confidence to continue treating low-risk patients and being comfortable with that.”

He added: “Outside the US, the guidelines are a little different. Maybe we should reconsider some of these guidelines based on these data.”

Commenting on these new results for theheart.org | Medscape Cardiology, David Moliterno, MD, Gill Heart and Vascular Institute, Lexington, Kentucky who is not involved in the TAVR studies, said: “The results provide a little more reassurance…that will go a little way further.”

“Uncertainty remains regarding long-term durability of the transcatheter valve in low-risk patients who are generally younger and likely more active than higher-risk cohorts,” he added. “The current 3-year results provide more confidence as the outcome curves for death and disabling stroke are trending in the right direction for TAVR vs surgery.”

Moliterno pointed out that while rates of paravalvular regurgitation and permanent pacemaker placement are decreasing with newer generation Evolut devices and implantation techniques, he noted that according to the US Social Security Administration, patients aged 74 years as enrolled in this low-risk cohort have an additional life expectancy of approximately 12 years. “So, we have more device durability (and coronary access feasibility) to prove.”

In his presentation, Forrest explained that TAVR is now approved in the US for all patients with aortic stenosis regardless of surgical risk and has become the dominant form of aortic valve replacement. Current ACC/AHA guidelines recommend that heart teams utilize a shared decision-making process when discussing aortic valve replacement with patients aged 65-80 years. In younger, lower-risk patients, the faster recovery and short-term benefits after TAVR must be balanced with long-term durability; however, only limited intermediate and long-term data exist to guide such discussions in this patient population.

The Evolut Low Risk trial randomly assigned 1414 patients in need of aortic valve replacement to TAVR with a self-expanding, supra-annular valve or surgery. Results at 1 and 2 years have shown a similar benefit in the primary endpoint of all-cause mortality/disabling stroke for the less invasive TAVR procedure.  

The current 3-year results suggest the benefit appears to be maintained out for another year. 

The main results show that the rate of death or disabling stroke was 7.4% in the TAVR group vs 10.4% in the surgery group, giving a hazard ratio of 0.70 (P = .051).

In the JACC paper, the authors report that the absolute difference between treatment arms for all-cause mortality or disabling stroke remained broadly consistent over time: -1.8% at year 1; -2.0% at year 2; and -2.9% at year 3.

Other key results on valve durability show that mild paravalvular regurgitation was increased in the TAVR group (20.3%) vs 2.5% with surgery. However, rates of moderate or greater paravalvular regurgitation for both groups were below 1% and not significantly different between groups.

Patients who underwent TAVR had significantly improved valve hemodynamics (mean gradient 9.1 mm Hg TAVR vs. 12.1 mm Hg surgery; P < .001) at 3 years.

However, pacemaker placement was much higher in the TAVR group (23.2%) compared with 9.1% in the surgery group.

On the other hand, the surgery group had a greater incidence of atrial fibrillation (40%) vs 13% with TAVR.

Quality-of-life results looked good in both groups.

“As we’ve come to expect, patients recover more quickly after TAVR, so at 30 days their quality of life is better than those who have undergone surgery,” Forrest commented. “But by 1 year, both groups are doing exceptionally well and, remarkably, here by 3 years both groups have greater than a 20-point increase in their KCCQ score, showing a very large improvement in quality of life.”

Discussant of these latest results at the ACC late-breaking trials session, James Hermiller, MD, St. Vincent Ascension Heart Center, Indianapolis, Indiana, said: “This 3-year data continues to demonstrate that the gift of TAVR keeps giving.”

Noting that the divergence in the effect curves was primarily driven by mortality rather than stroke, he asked whether this was cardiac or noncardiac mortality that was reduced.

Forrest responded: “It was a fairly equal contribution — a little bit more cardiac death. We have to remember that although the average age in this study was 74, there were some patients over 80 who were still low-surgical-risk included so we are going to see noncardiac death as well.”

High Pacemaker Rate With TAVR

Hermiller drew attention to the high pacemaker rate in the TAVR group and asked how these patients fared in comparison to those who didn’t need a pacemaker.

Forrest replied: “I think it’s fair to say that putting in a pacemaker is not a benign procedure.  Patients who got a pacemaker did slightly worse than those who didn’t get a pacemaker, so we need to try to drive that rate down.”

He added that the number of patients needing a pacemaker after TAVR has come down with new implantation techniques and new generation valves.

“We realize that using a cusp overlap technique can significantly reduce the need for a pacemaker, and we see from registry data that with the use of this new technique the need for a pacemaker has dropped down to 8%-9%, significantly less than seen in this study,” Forrest commented.    

Hermiller also asked about how TAVR affects future access for catheterization or percutaneous coronary intervention (PCI).  

Forrest noted that 24 patients in the TAVR group required PCI in first 3 years, and all the PCI procedures had been successful. He noted that operators reported the procedure to be easy or moderately easy in about 75%-80% of cases and difficult in about 20% of patients. “So, it is slightly more challenging to engage the coronaries and have to go through the frame, but it is very feasible.”

Forrest concluded that: “These results provide patients and heart teams important data to aid in the shared decision-making process.”

But he acknowledged that longer term data are still needed. “And the potential impact that hemodynamics, valve design, new pacemakers, and other secondary endpoints have on long-term outcomes will be important to follow in this group of low-risk patients.”

The Evolut Low Risk trial was funded by Medtronic. Forrest has received grant support/research contracts and consultant fees/honoraria/speakers bureau fees from Edwards Lifesciences and Medtronic.

American College of Cardiology (ACC) Scientific Session/World Congress of Cardiology (WCC) 2023. Late-Breaking Clinical Trials. Presented March 5, 2023.

J Am Coll Cardiol. Published online March 5, 2023.  Abstract

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