Partner IA: What It Means for Surgeons

Abstract

Since commercialization of transcatheter aortic valves in 2007, there have been an estimated 40,000 valves implanted in patients in 42 countries outside of the United States. Despite this extensive experience, there has been only one randomized controlled trial completed and a second one that is currently underway. The completed trial, the Partner Trial, was a randomized trial of the Edwards Lifesciences Sapien Valve, a bovine pericardial tissue valve mounted in a balloon deployable stainless steel stent. The Partner Trial was in fact 2 parallel trials of patients with severe aortic stenosis deemed to be either inoperable or at high risk for surgical aortic valve replacement (AVR) who were randomized against separate control groups. Inoperable patients, termed Cohort B, were randomized to transfemoral (TF) transcatheter aortic valve replacement (TAVR) or medical therapy, which included balloon valvuloplasty in 84% of patients.1 Three hundred fifty-eight patients were randomized equally between the 2 groups. The primary trial end point was superiority, and patients who received the transcatheter valve had an absolute 20% survival benefit at 1 year over control patients who received medical therapy only. These results were presented in July 2011 to an Expert Advisory Panel to the U.S. Food and Drug Administration, which recommended regulatory approval.2 That approval was granted in November 2011, and this valve is now available for commercial implantation for inoperable patients in the United States. The other arm of the trial, so-called Partner Cohort A, randomized 699 patients to TAVR by a TF approach or if they were not candidates for a TF approach to a transapical (TA) approach.3 That cohort of the trial resulted in 2 arms in which 244 patients received a TF valve and were compared with 248 surgical AVR controls. Those patients who were not candidates for the TF approach were random-