TAVR Holds Strong 3 Years Into Evolut Low Risk Trial

NEW ORLEANS -- Accruing clinical data continue to suggest that the choice between transcatheter aortic valve replacement (TAVR) and surgery is not an easy one for patients at low surgical risk who are deemed suitable for either procedure by a heart team evaluation.

Three years into the Evolut Low Risk trial, patients who underwent TAVR with the self-expanding Evolut device trended toward less all-cause mortality and disabling stroke compared with patients who underwent surgical aortic valve replacement (SAVR; 7.4% vs 10.4%, HR 0.70, 95% CI 0.49-1.00, P=0.051), reported John Forrest, MD, of Yale University School of Medicine in New Haven, Connecticut.

Moreover, the absolute difference between treatment arms has remained broadly consistent over time: the primary endpoint had reached 4.3% for TAVR versus 6.3% for SAVR at 2 years (log-rank P=0.084).

Forrest presented the 3-year data at the American College of Cardiology annual meeting. A full manuscript was published in the Journal of the American College of Cardiology.

Amy Simone, PA-C, director of Marcus Heart Valve Center at Piedmont Heart Institute in Atlanta, stressed the continued importance of shared decision making between low-risk patients with aortic stenosis and their clinicians. "Low surgical risk typically denotes younger age," and these patients are "extremely savvy and come to you knowing what they like," she said during a press conference. "As we're intervening on younger and younger patients, we need data-driven conversations."

TAVR has been FDA-approved for patients with aortic stenosis of all surgical risk levels since 2019, and has since surpassed SAVR in procedural volumes across the country.

In the current study, there were no between-group differences in clinical or subclinical valve thrombosis by 3 years. As was the case at 2 years, TAVR continued to be favored in terms of valve hemodynamics and prosthesis-patient mismatch.

However, whereas SAVR resulted in more new-onset atrial fibrillation compared with TAVR (40.0% vs 13.1%, P<0.001), a risk of conduction disturbance requiring permanent pacemaker (PPM) implant was higher in the TAVR group (23.2% vs 9.1% with SAVR, P<0.001).

PPM implantation has been linked to more complications after TAVR, longer hospital stays, and higher societal costs -- though its association with early mortality and heart failure is more controversial.

"Putting in a pacemaker is not a benign thing and we should aim to decrease this as much as we can," Forrest said.

He noted that operators had been using an outdated three-cusp technique during the study, and this has since been supplanted by the cusp overlap technique in the real world. According to TVT Registry data, the incidence of PPM with self-expanding TAVR valves has indeed dropped below 10% as recently as 2020.

"In addition, since this study was completed, the Evolut R valve has been replaced with the Evolut PRO and PRO+ valves, which have an external pericardial wrap on the lower valve frame that has been shown to further reduce paravalvular regurgitation [PVR]," Forrest and colleagues wrote.

The Evolut Low Risk trial enrolled patients at 86 centers on several continents. Low-risk patients with severe aortic stenosis were randomized to TAVR with a self-expanding, supra-annular bioprosthesis (i.e., CoreValve, Evolut R, or Evolut PRO) or surgery.

The as-treated cohort in the present analysis covered 1,414 patients (mean age 74 years, approximately 35% women) with an average Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score of 2%. The number of TAVR and SAVR recipients achieving 3-year follow-up reached 704 and 624, respectively.

TAVR valve performance at 3 years was marked by a disproportionate increase in mild-or-greater PVR after TAVR. This may not be clinically relevant, however, as a landmark analysis by 1-month echocardiograms showed that those with PVR had virtually the same incidence of death or disabling stroke as those without PVR.

Yet many agree that the fuller picture of TAVR will only emerge with 10-year follow-up of low-risk patients.

Long-term device durability is a uniquely important consideration for younger patients, and early hypoattenuated leaflet thickening of TAVR valves has been linked to subsequent symptomatic hemodynamic valve deterioration.

Session discussant James Hermiller Jr., MD, a structural heart interventionalist at St. Vincent Ascension Heart Center in Indianapolis, also remarked on lifetime management of people who have undergone TAVR and need repeat access for cardiac catheterization as they get older.

Forrest reported that 24 patients in the TAVR arm of the study required percutaneous coronary intervention in the first 3 years. This was successful in all 24 cases, but about a quarter of the time the operator judged it difficult to go through the device frame.

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