Transcatheter Aortic Valve Implantation (TAVI) is as effective as surgery for patients with aortic stenosis who are classified as low risk, a major trial has shown.
TAVI is currently reserved for high-risk patients who are deemed unsuitable for surgery, but findings from a multinational trial presented at the American College of Cardiology’s 2019 annual scientific meeting in New Orleans showed no difference in the combined rate of disabling stroke or death from any cause at two years between TAVI and standard surgery.
The randomised, prospective study included 1,468 patients with a mean age of 74 years and severe, symptomatic aortic stenosis from 86 international centres including the Alfred hospital, Melbourne.
Low risk was defined as a predicted 30-day mortality of 3% or less for 30 days post-surgery.
In the trial, 725 patients received TAVI with a self-expanding device and 678 patients underwent surgical aortic valve replacement (SAVR) with bioprosthetic surgical valves.
The trial included first- and second-generation valves (3.6% CoreValve, 74.1% Evolut R, while the new third generation Evolut Pro valve was introduced late in the trial and was implanted in 22.3% of patients enrolled.
The 24-month estimated incidence of the primary end point of combined rate of disabling stroke or death from any cause was 5.3% in the TAVI group and 6.7% in the surgery group, according to results published simultaneously in NEJM.
At 30 days, patients who had undergone TAVI, as compared with surgery, had a lower incidence of disabling stroke (0.5% vs. 1.7%), bleeding complications (2.4% vs. 7.5%), acute kidney injury (0.9% vs. 2.8%), and atrial fibrillation (7.7% vs. 35.4%) and a higher incidence of moderate or severe aortic regurgitation (3.5% vs. 0.5%) and pacemaker implantation (17.4% vs. 6.1%).
The study’s senior author, Professor Michael J. Reardon, head of cardiothoracic surgery at Houston Methodist Hospital, said TAVI was superior to surgery at 30 days for outcomes of mortality or disabling stroke, quality of life and time in the hospital.
“In other words, you’re more likely to be alive without a disabling stroke, get out of the hospital sooner—in half the time—and have a better quality of life one month after getting a new valve,” he said, noting that hospital stays were twice as long for patients undergoing surgery than they were for TAVI, (6.2 days vs 2.6 days on average).
At 12 months, patients in the TAVI group had lower aortic-valve gradients than those in the surgery group (8.6 mm Hg vs. 11.2 mm Hg) and larger effective orifice areas (2.3 cm2 vs. 2.0 cm2). Hospitalisation for heart failure occurred in 3.2% of TAVI patients and 6.5% of surgical patients at one year.
Patients receiving TAVI reported significantly better quality of life, 20 vs. 9.1 at one month post-procedure. By one year, both TAVI and surgery had similar improvements in quality of life, 22.2 and 20.9, respectively.
“We’ve now looked at a broad risk spectrum of patients—those at high, intermediate and low surgical risk—and these series of trials have shown that [TAVI] is better than or as good as surgery in terms of disabling strokes and deaths from all causes. When we look at secondary outcomes of quality of life and functional recovery, these seem to favour [TAVI] at this point,” said Professor Reardon.
“Given this data, it now seems reasonable to consider moving [TAVI] in low risk patients to a class I guideline indication on par with surgery for patients with severe aortic stenosis.”
However he acknowledged that the relatively short follow up time was a limitation of the trial. And because patients with bicuspid aortic valves and those with anatomic incompatibility for TAVI valves were excluded, as were patients needing other major cardiac surgical procedures such as mitral valve repair, researchers could not say how these patients might fare.
In an analysis of the results at ACC19, Dr Dharam Kumbhani an interventional cardiologist at UT Southwestern Medical Center described the EVOLUT LOW RISK study as “a landmark trial in this field”.
“Paired with the results of the PARTNER 3 trial, these findings suggest that low surgical risk patients do as well and perhaps even better with TAVR compared with SAVR over 2 years of follow-up,” he said.
“Long-term follow-up is going to be essential to understand long-term performance and the risk of subclinical leaflet thrombosis and structural valve degeneration. If approved by the FDA, it will open up TAVR as a treatment option to a much larger pool of patients with aortic stenosis.”