SAN FRANCISCO—All-cause and cardiovascular mortality were similar for transcatheter aortic valve replacement (TAVR) compared to open-heart surgery in high-risk older patients at three years with no increased risk of stroke after 30 days, according to three-year data from the PARTNER study presented March 11 at the American College of Cardiology’s (ACC) scientific session.
The PARTNER I study assigned 699 high-risk patients with faulty aortic valves to standard surgery (351 patients) or TAVR (348 patients). At three years, all-cause mortality was nearly identical in both groups: 44.8 percent for standard surgery compared to 44.2 percent for TAVR. Cardiovascular mortality rates also were statistically indistinguishable at 30.2 percent for standard surgery and 30.1 percent for TAVR.
Both groups displayed similar improvements in symptoms that have been maintained for three years, reported the study’s lead author, Vinod H. Thourani, MD, of the division of cardiothoracic surgery at Emory University School of Medicine in Atlanta, during the trial presentation.
With the much higher stroke rate reported for TAVR at 30 days, Thourani said that the other concern in this study has been whether a higher stroke risk would persist beyond that 30-day periprocedural window. This did not appear true at two or three years, as the TAVR stroke rates were 6 percent at one year, 7.7 percent at two years and 8.2 percent at three years, compared with 3.2 percent, 4.9 percent and 9.3 percent for standard surgery.
“At three years, the surgery group’s stroke rate has caught up with and slightly surpassed the TAVR rate but not to statistical significance,” he said. “Initially, when we implanted the valves in 2006 and 2007, we were concerned that we would continue to see strokes. That is not what we have seen at two and three years, even though most TAVR patients are taken off of clopidogrel at six months.”
To the quality of life question, 80 percent of patients in both arms reported symptom relief.
However, paravalvular leaks were common soon after the procedure and were overwhelmingly higher in the TAVR group, and even mild aortic leakage is associated with a higher mortality rate after any valve replacement procedure, Thourani noted. In fact, the echocardiographic analysis revealed that post-procedural paravalvular aortic regurgitation was frequent after TAVR (mild-mod-severe in approximately 50 percent patients) without important changes during three-year follow-up. Even mild post-procedural aortic regurgitation (paravalvular and total aortic regurgitation) was associated with increased subsequent mortality.
“However, we learned that the paravalvular are not increasing over time, they are staying stable and not getting worse,” said Thourani.
Study panelist Michael A. Quinones, MD, of Methodist DeBakey Cardiology Associates in Houston, noted a difference between the paravalvular leaks from randomized trial vs. registry data in Europe. In contrast to the PARTNER findings, registries are not showing that the leaks actually lead to worse clinical outcomes, he said.
Addressing the durability question of the valves, study panelist Christopher P. Cannon, MD, of Brigham and Women’s Hospital in Boston, said that there is comfort to know that they “aren’t falling apart at three years.” Thourani added that these patients were followed out to a minimum of three years.
“Are we at the stage that we can clinically assess which patients are appropriate for CABG vs. surgery?” asked study panelist Michael Mack, MD, medical director of cardiovascular services and director of transplantation for Medical City Dallas Hospital in Houston.
“Clinically, we are already doing that,” said Thourani, noting that the TVT Registry will also inform those decisions for guideline recommendations.
Quinones concluded that these findings reinforce the fact that “TAVR is here to stay.”