April 5, 2011 – Death rates are similar at one year for a catheter-based aortic valve replacement procedure and conventional surgery in older high-risk patients. Results from Cohort A of the PARTNER trial found that survival of patients treated with the Edwards Sapien transcatheter aortic valve was equivalent to those treated with surgical aortic valve replacement in the head-to-head comparison.
The data were presented at the American College of Cardiology's (ACC) 60th Annual Scientific Session and Expo in New Orleans this week.
“Large-scale, randomized comparisons of new interventional procedures to gold-standard surgical procedures have seldom been done,” said Craig R. Smith, M.D., chief of the Division of Cardiothoracic Surgery, New York-Presbyterian Hospital/Columbia University Medical Center, and the study’s co-principal investigator. “This is the ideal opportunity, because surgical AVR is one of the most effective operations surgeons offer, and TAVR is the most exciting new treatment for aortic stenosis in the past two to three decades.”
In patients with aortic stenosis at high risk for surgery, transcatheter aortic valve replacement (TAVR) was non-inferior to surgical aortic valve replacement (AVR) for all-cause mortality at one year, 24.2 percent versus 26.8 percent, respectively. In addition, mortality at 30 days was lower than expected in both arms of the trial, with TAVR at 3.4 percent and AVR at 6.5 percent. The observed mortality in these AVR patients was lower than the predicted risk of operative mortality of 11.8 percent. Even with this early generation device and limited operator experience, the TAVR mortality was the lowest reported in any multi-center series of clinical data for the valve.
"It is a highly significant demonstration for transcatheter aortic valve repair for non-inferiority with surgery," Smith said.
TAVR’s centerpiece is a wire mesh stent encasing three sutured-on valve flaps called leaflets, made from cow tissue and treated to cut down on calcium deposits that cause stenosis. Cardiologists deliver the bioprosthetic valve to its target location with a catheter guided from a leg artery to the heart (transfemoral access; TF) or through the ribs (transapical access; TA) if peripheral arteries are not large enough. Like standard valve replacement, this procedure is performed under general anesthesia.
A total of 699 high-risk older patients with severe aortic stenosis were randomly assigned at 26 centers to TAVR or to AVR. The median age was 84.1 years. The TAVR group totaled 348 patients (244 TF, 104 TA); 350 patients were in the AVR group. Patient characteristics were similar overall across cohorts, but the patients assigned to TA TAVR had a higher risk profile. Endpoints included death from any cause at one year (primary endpoint), stroke and major vascular and bleeding events.
Although 30-day results favored TAVR for all-cause deaths (3.4 percent vs. 6.5 percent) and improvement in symptoms, both rates were similar at one year. Major strokes were higher for TAVR at both 30 days (3.8 percent vs. 2.1 percent) and one year (5.1 vs. 2.4 percent). At 30 days major vascular complications also were much more common after TAVR (11 vs. 3.2 percent), but the TAVR group’s rates were much lower for major bleeding (9.3 vs. 19.5 percent) and new-onset irregular heart rhythms of atrial fibrillation (8.6 vs. 16 percent). Para-valvular regurgitation – leaks alongside or near the valve – occurred more often after TAVR as well.
“These results clearly show that TAVR is an excellent alternative to surgical AVR in high-risk patients,” Smith said. “Recommendations to individual patients will need to weigh the appeal of avoiding open-heart surgery, with its known risks, against less invasive TAVR with different and less well understood risks, as well as the absence of long term follow-up. Future trials will help delineate the role of TAVR in intermediate risk patients.”
A follow-up PARTNER II Trial was approved in February 2011 to test the next generation of this novel valve and a different catheter delivery system against the valve and delivery method used in the first PARTNER Trial.
The trial is funded by Edwards Lifesciences, Inc. Smith has no financial relationship with the company.
The Road to U.S. Market Approval
"We are enthusiastic that this trial clearly demonstrates the promise of a less-invasive treatment for patients at high risk for surgery,” said Michael A. Mussallem, Edwards' chairman and CEO. “Although this therapy is still relatively new and rapidly evolving, it is impressive that the patient outcomes are similar to the well-established standard of open heart
Edwards expects to submit the data from Cohort A of the PARTNER trial to the U.S. Food and Drug Administration (FDA) in the second quarter. Results from the inoperable Cohort B of the trial also met the primary endpoints and were published in The New England Journal of Medicine. These data are currently under review by the FDA.
For more information: www.edwards.com