SAN DIEGO—So it wasn’t a fluke. Two-year results from the CoreValve pivotal trial for high-risk patients with severe aortic stenosis reaffirmed that the transcatheter aortic valve replacement (TAVR) device is superior to standard surgery. The results were presented March 15 at the American College of Cardiology scientific session.
“Our survival advantage that we saw at one year is both durable and sustainable, and in fact it is actually widening over time,” presenter Michael J. Reardon, MD, of Houston Methodist Hospital, told Cardiovascular Business. “That is a really provocative thought. What is three years going to look like? Will it continue to widen?”
The CoreValve U.S. Pivotal High Risk Trial randomized 390 high-risk patients to receive TAVR treatment using Medtronic’s self-expanding CoreValve device and 357 to surgical aortic valve replacement between February 2011 and September 2012. At one year, the all-cause mortality rate for the TAVR group was 14.2 percent vs. 19.1 percent for the surgical group. By two years, the rate was 22.2 percent vs. 28.6 percent. TAVR achieved a 6.5 percent relative benefit over surgical aortic valve replacement.
The one-year results unveiled at ACC.14 met noninferiority and superiority endpoints for all-cause mortality. But some physicians at that conference questioned whether slight differences in deaths would challenge the margin that favored TAVR. “There was a lot of discussion about how robust was our superiority,” Reardon recalled.
For stroke, the difference between the two treatments widened from year one to year two. At year one, 12.5 percent of the surgical group experienced stroke compared with 8.7 percent of the TAVR group. One year later, that gap widened to 16.6 percent vs. 10.9 percent. “That means TAVR is actually, for all stroke, superior to surgery,” he said.
Major stroke was also higher in the surgery group, but it did not reach statistical significance. By year two, stroke and all-cause mortality together reached a difference of 8.6 percent, which was statistically significant.
Based on echo studies evaluated in a core lab, hemodynamically TAVR beat out surgery at every point. “It has been sustained at a consistent level and we have not seen any valve deterioration at any point,” he said. “The rate of structural valve deterioration is at least in the time frame we looked at is going to be very low, if you implant these valves properly.”
For complications, TAVR was more commonly associated with vascular injuries and the need for pacemakers. Disabling or life-threatening bleeding with transfusion, new or worsening atrial fibrillation acute kidney injury were more common with surgery. “Each one of those has early risk to life and ongoing late risk to life,” he said.
TAVR with the CoreValve device also proved superior in all subgroup analyses. “The data suggest that TAVR with the self-expanding transcatheter heart valve really is the preferred alternative in this group,” Reardon said at the late-breaking clinical trial presentation. “It sets the bar and it sets the bar high.”
Several panelists and Reardon commented on the differences between the CoreValve and PARTNER trials. PARTNER, which preceded the CoreValve trials, was the pivotal trial for Edwards Lifesciences’ Sapien TAVR valve. CoreValve used 3D CT imaging and more valve sizes and based stroke on National Institutes of Health Stroke Scale scores.
At a press release, Athena Poppas, MD, of Rhode Island Hospital in Providence, summed it up. “This really does move the needle forward,” she said, adding that durability will remain a question going forward.
Medtronic funded the study.