SAN FRANCISCO – A new, smaller version of the only transcatheter aortic valve available for U.S. use showed noninferior clinical outcomes and safer periprocedural results in a multicenter U.S. comparison of the new and existing devices in a total of 560 patients, raising expectations that the new valve system – the Sapien XT – will soon be on the U.S. market.
Although treatment using the Sapien XT roughly matched treatment with the existing Sapien transcatheter aortic valve in the incidence of the important adverse effect of residual moderate or severe paravalvular leak, several U.S. operators who perform transcatheter aortic valve repair (TAVR) stressed that the leak problem has begun to resolve recently as interventionalists and surgeons have found ways to minimize the issue. They also noted that availability of the new XT device will move the field a step further toward fewer leak issues, because it will allow the option of a larger, 29-mm-diameter valve, a possibility that has not been available with the original Sapien valve.
Mitchel L. Zoler/IMNG Medical Media
Dr. Martin B. Leon
"Sapien XT represents a worthwhile advance with incremental clinical value, and it is the preferred balloon-expandable transcatheter aortic valve system," said Dr. Martin B. Leon when he presented the trial data on March 10 at the annual meeting of the American College of Cardiology.
"This second-generation device has demonstrated sufficient clinical benefit for us to say it’s the preferred therapy," said Dr. Leon, professor of medicine and director of the Center for Interventional Vascular Therapy at Columbia University in New York.
"This is an evolutionary technology that is easier to use. The results are superb," commented Dr. Gary S. Mintz, an interventional cardiologist based in Washington and medical director of the Cardiovascular Research Foundation in New York.
The PARTNER II (Placement of Aortic Transcatheter Valves) cohort B trial enrolled 560 patients with aortic stenosis deemed inoperable for surgical valve replacement at 28 U.S. centers during April 2011 through February 2012. The study randomized patients to receive the Sapien XT valve or the approved Sapien valve in a prespecified noninferiority design, with a primary outcome of all-cause death, disabling stroke, or need for repeat hospitalization at 1 year after treatment. Patients averaged 84 years old, they had an average Society of Thoracic Surgeons score of about 10%, 96% had New York Heart Association class III or IV heart failure, and about 60% met the study’s criteria for frailty.
At 1-year follow-up, the combined primary endpoint occurred in 35% of patients treated with the approved valve and in 34% of patients treated with the new XT valve, a result that was not statistically significant and that met the study’s standard for noninferiority. At 1 year, as well as at 30 days after treatment, the two patient groups showed no significant difference for any of the individual components of the clinical endpoints.
However, patients treated with the XT valve had significantly fewer procedural complications, with significantly fewer major vascular events (10% with the XT device, compared with 16% with the approved valve) and significantly fewer disabling bleeding events (8% with the XT device, compared with 13% with the first-generation system), Dr. Leon reported. The category of major vascular events included perforations, dissections, and hematomas. Patients treated with the XT device also required significantly fewer episodes when the initially placed valve had to be replaced (3 replaced valve implants, compared with 10 using the approved valve), and numerically fewer aborted procedures – 2 compared with 8 using the approved valve, although this difference just missed statistical significance (P = .06). Placement of the new valve also required an average of 14 minutes less anesthesia time, a significant difference.
"It’s a smaller device. What you would expect from a smaller device is fewer vascular complications and improved procedural events," Dr. Leon said in an interview. He also highlighted the numerical difference in 30-day mortality – 5.1% with the older valve system, compared with 3.5% using the XT device. While the difference did not reach statistical significance, "to me this difference is not trivial," he said.
The difference in disabling bleeding complications is also important, commented Dr. Mintz, who was not involved in the study. "Bleeding complications are hugely disabling, especially in this older, frail population," he said.
"The big concerns from the first PARTNER trial were vascular complications, strokes, and paravalvular leaks," said Dr. Leon. "The XT device seems to address some of these issues. The vascular complications were reduced, and the stroke rate went down" compared with the first PARTNER trial (N. Engl. J. Med. 2010;363:1597-607). "What is left is the paravalvular leak issue, which is real."