After taking it to the chin to report in advance the Bayesian estimates, the actual 2-year data from the EVOLUT Low Risk trial confirm that catheter aortic valve replacement (TAVR) is not inferior to surgery for the primary endpoint of death or disability stroke.
Among the 1414 patients treated, all-cause death rates or disabling Kaplan-Meier stroke at 24 months were 4.3% with TAVR and 6.3% with surgery (Pg = 0.084).
There were also no differences in the individual components of death from all causes (3.5% vs. 4.4%; log-rank Pg = .366) and deactivator trace (1.5% vs 2.7%; log record) Pg = .119).
Recent low-risk TAVR studies have raised questions about whether there is a possible recovery from surgery between 12 and 24 months, given the benefit of early mortality derived from the less invasive transcater procedure, which has led to a baseline analysis, John K. Forrest, MD, said during the virtual presentation at the Congress of the European Association of Percutaneous Cardiovascular Interventions of 2021 (EuroPCR 2021).
“Between 1 and 2 years, there was no convergence of Kaplan-Meier curves for death or disabling stroke,” with an incidence of 1.9% for the TAVR group and 2.1 % for the surgery group (log-rank Pg = .742), said Forrest, of the Yale School of Medicine, New Haven, Connecticut. “The lines were almost overlapping.”
The session moderator, Bernard Prendergast, MD, noted that Bayesian analysis, which was reported in 2019 and followed up for 12 months to predict the two-year results, generated questions and criticisms about whether this was an appropriate method, compared to traditional Kaplan-Meier analysis. “In fact, some people accused researchers of playing with this form of statistical analysis.”
To act as a “fact checker,” he called Prendergast Christopher Cook, MRC, of the PCR Clinical Research Group and Imperial College London. The key methodological question, Cook said, is whether Bayesian methods accurately predict actual clinical outcomes in this randomized clinical trial. “The simple answer to that is yes.”
He noted that Kaplan-Meier data for the primary outcome at 2 years were, in fact, numerically better than the Bayesian estimates of 5.3% in the TAVR group and 6.7% in the surgery group.
“This validates the use of original Bayesian methods to estimate patient outcomes in low-risk TAVI patients, and in fact can act as an example of where Bayesian methods can be safely applied to quickly monitor procedures and potentially transformative technologies in our patients, ”Cook said.
The rate of disabling stroke with TAVR was 1.5% in the new analysis, 1.1% in the Bayesian analysis and 2.7% in surgery, compared to 3.5 % in Bayesian analysis.
Mortality for all causes, also noted above, was 3.5% with TAVR and 4.4% with surgery, while the Bayesian estimate was 4.5% for each group.
Prendergast, of St. Thomas’ from London said the actual two-year data are reassuring in terms of the statistical tools used and complement those recently reported from low-risk patients in London. MEMBERS 3.
But, he asked, “what does this mean for practice, what does it mean for guidelines and how long do we have to wait until we are comfortable and make sure we can apply TAVI in younger, low-risk patients with a result? durable? “
Forrest said doctors can be sure these patients are “doing very well,” but that long-term follow-up is critical.
“We have to be realistic here. We will really be interested in the results in 5 and 10 years and potentially even after,” he said. “What happens to these valves when they finally fail? Will the superior hemodynamics provide us with greater durability of the valves in some way or will there be other contingencies that appear ten years later? We don’t know these answers.”
TAVR with a supra-annular and self-expanding valve (CoreValve , Evolut R, or Evolved PRO) had superior hemodynamics in the new 2-year analysis with lower aortic valve gradients (9.0 vs 11.7 mm Hg) and larger valve areas (2.2 vs 2.0 cm).2).
The mismatch between prosthesis and patient also favored TAVR, with a moderate or severe mismatch in 7.2% and 2.1%, respectively, compared with 19.1% and 4.9%, respectively. with surgery. “We know this has an impact on long-term results, so it’s important to keep that significant difference in mind here,” Forrest said.
The TAVR armor gap remains a paravalvular leak, especially a mild leak, which was significantly higher with 26.6%, compared with only 2.6% with surgery. Moderate to severe leaks were observed at 1.7% and 0.4%, respectively, reflecting TAVR improvement with new iterations, he said.
Surgery was also superior to TAVR in terms of the need for permanent pacemaker implantation (7.9% vs. 21.1%). This compares with Bayesian estimates of 6.7% and 23.0%, respectively.
Rates of myocardial infarction remained constant in both analyzes for the TAVR (2.2%) and surgery (1.6%) groups, while heart attack hospitalizations improved slightly, from 5.4% vs. 7.9%, respectively, in the Bayesian analysis to 5.3% versus 7.1%, respectively, in the new analysis.
Discussion partner Marie-Claude Morice, MD, Institut Hospitalier Jacques Cartier, Massy, France, highlighted several meta-analyzes in different at-risk patients showing “a lot of good news,” including mortality and stroke rates and the combined result that clearly favors TAVR.
“The remaining issue is the longevity of the valve, but with a 5-year follow-up we have a comparison [in high-risk patients], it’s the same, “he said.” What this illustrates is that the TAVR tide continues and we can look to the future with optimism. Are patients asymptomatic? “
Medtronic funded the study. Forrest reported support for the grant, which was part of the advisory board and hired Edwards Lifesciences and Medtronic. Prendergast has received grants from Edwards Lifesciences; and fees / consultants for Abbott, Anteris and Edwards.
The Congress of the European Association of Percutaneous Cardiovascular Interventions (EuroPCR) of 2021. Filed May 18, 2021.