- A pair of highly anticipated studies presented at the American College of Cardiology meeting in New Orleans this weekend found low surgical risk patients did as well or better after minimally invasive transcatheter aortic valve replacement (TAVR) compared with patients who received new valves in an open heart surgical procedure.
- In the Partner 3 study comparing TAVR using Edwards Lifesciences' Sapien 3 valve to conventional surgery in 1,000 severe aortic stenosis patients, TAVR was superior to surgery at preventing death, stroke and repeat hospitalization at one year, researchers said.
- Separately, the Medtronic Evolut Low Risk trial of 1,403 patients with severe aortic stenosis showed that TAVR was as good as surgery on the primary endpoint of mortality and disabling stroke at 24 months.
Cardiologists attending the heart meeting, including those not affiliated with the studies, said the results could lead to a new standard of care. Wall Street analysts also said the class of technologies as a whole will likely benefit.
Still, Jefferies analysts gave a slight edge to Edwards in comparing the results, noting superiority in all-cause mortality over Medtronic. Edwards shares rose roughly 10% in mid-morning trade Monday, while Medtronic shares edged down around 2%.
And the market just got fiercer for Boston Scientific's Lotus, a TAVR system not yet approved in the U.S., analyst Raj Denhoy said.
"The bar has also been set higher for new technologies," Denhoy wrote in a note to clients.
The data prompted predictions that TAVR will become the preferred option for a wider population of heart valve patients.
"This is a game-changing trial, because those who were skeptical that these valves would be as good or better than really great surgery can now rest assured. A patient at low risk can say 'I want a non-surgical approach with good confidence. I do think it changes our practice'," said Kim Eagle, director of the Frankel Cardiovascular Center at the University of Michigan and editor of ACC.org, in a video posted on the ACC website.
TAVR involves threading a replacement valve through the arteries via a catheter inserted in the groin or chest. Once reserved for patients considered ineligible for open heart surgery or at high risk of death or complications, TAVR gained FDA approval for use in intermediate risk patients in August 2016. The pool of eligible patients is now expected to expand further, supported by the positive data for low surgical risk patients.
"Given this data, it now seems reasonable to consider moving TAVR in low risk patients to a class I guideline indication on par with surgery for patients with severe aortic stenosis," said Michael Reardon, chair of cardiovascular research at Houston Methodist Hospital and senior author of the Medtronic Evolut study, in a press release from ACC.
The strength of the results in the Partner 3 study surprised the research team, which had hoped TAVR would prove comparable to surgery, said lead author Martin Leon, director of the Center for Interventional Vascular Therapy at New York-Presbyterian/Columbia University Irving Medical Center.
The Partner 3 trial's primary endpoint was the combined rate of all-cause death, stroke and rehospitalization at one year after the procedure. The study showed a 46% reduction in the primary endpoint, from 15.1% in the surgical group to 8.5% with TAVR. Each component of the primary endpoint also favored TAVR.
Aortic stenosis is a condition in which the valve in the heart's main artery doesn't open efficiently, causing the heart to have to work harder to pump blood. Patients at low surgical risk comprise the majority of people who are candidates for surgery to have their aortic valve replaced.
"This is a landmark study because it involves 80% of the people who are currently being treated with surgery for aortic stenosis," Leon said in a press release. "This is beyond anything we could have expected, mostly because surgery is so good in treating aortic stenosis in these low risk patients."
In the Medtronic study, TAVR was superior to open heart surgery for major stroke, occurring in 0.8% of TAVR patients and 2.4% of surgical patients. TAVR had lower rates of all-cause mortality, at 2.4% vs. 3% for surgery, but it was not statistically significant. Hospitalization for heart failure occurred in 3.2% of TAVR patients and 6.5% of surgical patients at one year. Most patients in the study received Medtronic's CoreValve Evolut valve; 22.3% got the third-generation Evolut PRO.
Expanded use of TAVR to a lower risk population would mean more patients would be likely to get the valves at a younger age. Longer-term follow-up data are needed to determine if transcatheter valves are as durable as surgical valves, cardiologists said. The average age of patients in the Partner 3 trial was 73 years, and the average age of patients in the Evolut trial was 74 years. Both research teams plan to follow patients for 10 years.