One-Year Results of Emory-Led TAVR Study Confirm Efficacy
Vinod Thourani, MD, professor of surgery, chief of cardiothoracic surgery at Emory University Hospital Midtown, and co-director of the Emory Structural Heart and Valve Center with Emory cardiologist Vasilis Babaliaros, MD, announced the one year-results of the PARTNER II, SAPIEN 3 clinical trial on April 3rd at the American College of Cardiology's 65th Annual Scientific Session in Chicago. He was also the lead author of the study report published online by The Lancet the same day. The trial compared transcatheter aortic valve replacement (TAVR) using the latest-generation SAPIEN 3 valve to traditional surgical aortic valve replacement for intermediate-risk patients with severe aortic stenosis. The investigators found that the patients who received TAVR generally fared better.
Aortic valve replacement is the treatment of choice for aortic stenosis, which is characterized by a narrowing of the opening to the aortic valve that restricts blood flow. Traditional surgical replacement involves opening the chest, while in TAVR physicians thread the replacement valve to the heart through a catheter placed in the groin or ribs.
"This study shows the lowest mortality rate ever of any transcatheter valve platform after one year, which is very exciting for the management of aortic stenosis," says Dr. Thourani. "A previous analysis by our team showed that almost 20 percent of all patients undergoing surgical aortic valve replacement in the United States are in the intermediate-risk category, so this could have a major impact on the treatment options we have available for many of these patients."
The trial involved more than 1,000 patients who received TAVR with SAPIEN 3 at 51 U.S. hospitals between Feb. 17, 2014, and Sept. 3, 2014. Participants, who averaged nearly 82 years of age, had an STS risk score of 4 to 8, a range considered intermediate, on a scale developed by the Society of Thoracic Surgeons that quantifies the risks posed by open-heart surgery for a given patient. These patients were compared with patients randomized to receive surgical intervention between Dec. 23, 2011, and Nov 6, 2013, in a precursor study, PARTNER 2A. A prespecified propensity score analysis was applied to account for between-trial differences in baseline characteristics. The results of PARTNER 2A were similar, and published on April 2 in the New England Journal of Medicine.
In PARTNER II's primary endpoint, a composite of death, stroke, and moderate or severe aortic insufficiency (leaking of the aortic valve), TAVR was found to be superior to surgery at one year, occurring 9.2 percent less in the TAVR patients. TAVR was also superior to surgery for two out of three secondary outcomes, mortality and stroke.
As has been the case in prior studies, moderate to severe aortic insufficiency occurred less in surgery patients, and TAVR patients needed pacemakers at a slightly higher rate at one year than patients receiving surgery. However, the intermediate-risk TAVR patients in the new trial showed marked improvements in outcomes as compared to high-risk TAVR patients in previous trials.
The improved success of the SAPIEN 3 TAVR procedure in intermediate-risk TAVR patients could be due to the third-generation SAPIEN model having been modified with an outer skirt designed to reduce leaking by sealing gaps around the valve. The valve is also delivered with a smaller catheter, making it possible to perform more procedures via the femoral artery accessed through the groin, a route that is considered safer than going through the ribs.
"The improvements with the SAPIEN 3 valve have made this an easier procedure to perform, and this study shows that we can do it with extremely low complications and mortality. I believe we are on the cusp of a new indication for TAVR," Dr. Thourani says.
Patients in the trial will continue be followed for five years.
Emory was the first site in Georgia and among the first in the U.S. to begin participating in Edwards Lifesciences' multi-center studies of TAVR using its SAPIEN family of valves in 2007. Drs. Thourani and Babaliaros have been consistent co-PIs of the Emory-based studies, providing evidence and conclusions that were instrumental to the FDA's 2011 approval of the SAPIEN 1 valve for inoperable patients, as well as the FDA's 2015 approval of the SAPIEN 3 valve for the treatment of high-risk patients who are not candidates for open-heart valve replacement surgery. Use of the valve for treating intermediate-risk patients in the U.S. is not yet approved. To date, Drs. Thourani, Babaliaros, and their Emory colleagues have performed approximately 1,500 TAVR procedures, making Emory the largest TAVR provider in the Southeast.
"Transcatheter Aortic Valve Replacement Versus Surgical Valve Replacement in Intermediate-Risk Patients: A Propensity Score Analysis." Thourani VH, Kodali S, Makkar RR, Herrmann HC, Williams M, Babaliaros V, Smalling R, Lim S, Malaisrie SC, Kapadia S, Szeto WY, Greason KL, Kereiakes D, Ailawadi G, Whisenant BK, Devireddy C, Leipsic J, Hahn RT, Pibarot P, Weissman NJ, Jaber WA, Cohen DJ, Suri R, Tuzcu EM, Svensson LG, Webb JG, Moses JW, Mack MJ, Miller DC, Smith CR, Alu MC, Parvataneni R, D'Agostino RB Jr, Leon MB. Lancet. 2016 Apr 1. [Epub ahead of print]
"Transcatheter or Surgical Aortic Valve Replacement in Intermediate-Risk Patients." Leon MB, Smith CR, Mack MJ, Makkar RR, Svensson LG, Kodali SK, Thourani VH, Tuzcu EM, Miller DC, Herrmann HC, Doshi D, Cohen DJ, Pichard AD, Kapadia S, Dewey T, Babaliaros V, Szeto WY, Williams MR, Kereiakes D, Zajarias A, Greason KL, Whisenant BK, Hodson RW, Moses JW, Trento A, Brown DL, Fearon WF, Pibarot P, Hahn RT, Jaber WA, Anderson WN, Alu MC, Webb JG; PARTNER 2 Investigators. N Engl J Med. 2016 Apr 28;374(17):1609-20. Epub 2016 Apr 2.