Self-expanding TAVR noninferior to SAVR in intermediate-risk AS patients
Transcatheter aortic valve replacement (TAVR) with a self-expanding prosthesis is noninferior to surgical aortic valve replacement (SAVR) in terms of death from any cause or disabling stroke at 2 years in intermediate-risk patients with severe aortic stenosis (AS), according to data from the SURTAVI* trial presented at the ACC.17 held in Washington, DC, US.
“We know that in patients that are at high surgical risk, TAVR with the self-expanding valve is superior to surgery,” said lead author Professor Michael Reardon of the Methodist DeBakey Heart and Vascular Center in Houston, Texas, US. “What we don’t know yet is the comparative efficacy as we move down the risk scale to lower surgical risk.”
The prospective multicentre study included 1,746 patients (mean age 79.8 years) with symptomatic, severe AS at intermediate surgical risk, who were randomized to self-expanding TAVR (n=879) or SAVR (n=867). Patients were stratified by their need for revascularization in the analysis, unlike the previous PARTNER** trial which stratified patients by the access route of the catheter. [ACC.17, abstract LB-16607; N Engl J Med 2017;doi:10.1056/NEJMoa1700456]
At 24 months, the primary endpoint comprising a composite of disabling stroke or all-cause mortality occurred at a lower rate in patients who underwent TAVR than SAVR (12.6 percent vs 14.0 percent), with a posterior probability of noninferiority of >0.999, which according to Reardon, corresponds to a one-sided p<0.001.
“TAVR was just as good as surgery, but it was not statistically superior to it,” said Reardon, attributing the difficulty to meet superiority to the low mortality rate in the surgical group, despite TAVR having a favourable disabling stroke rate over SAVR at 2 years (2.6 percent vs 4.5 percent).
The two approaches showed different safety and complication profile, with the TAVR group having lower rates of acute kidney injury (stage 2 or 3), atrial fibrillation, transfusion needs, and superior quality of life than the SAVR group at 30 days, but higher rates of major vascular complication, residual aortic regurgitation and pacemaker implantation, although the need for new pacemaker was not associated with increased mortality.
In addition, TAVR resulted in significantly improved aortic-valve (AV) haemodynamics with lower mean gradients and larger AV areas than SAVR through 24 months follow-up.
“These are outstanding data,” said Reardon. “The guidelines were just updated and for intermediate-risk, TAVR is now a 2a, but with this data it will need updating and [should even get] a class 1 indication.”
Nonetheless, cardiologists should not confuse the favourable results for intermediate-risk group as an “OK” to treat patients younger and earlier in life, cautioned session chair Dr Valentin Fuster, who is also the editor-in-chief of the Journal of the American College of Cardiology.
"While this study further supports the safety and efficacy of TAVR in intermediate risk patients, demonstration of comparable long term durability of TAVR compared to SAVR out to 10 years and beyond is critical to decision making in younger individuals," said Professor Kim Eagle, director of the Frankel Cardiovascular Center at the University of Michigan in Ann Arbor, Michigan, US, who is also the editor-in-chief of ACC.org.
Following the presentation, the FDA has approved the CoreValve Evolut Pro device used for TAVR in 16 percent of the study patients.