Under-expansion is a potential factor in clinical outcomes for patients with severe, symptomatic aortic stenosis (AS) receiving the ACURATE neo2 valve, results from the head-to-head ACURATE IDE trial show. Michael J. Reardon, MD, of Houston Methodist DeBakey Heart & Vascular Center, presented these results during a late-breaking trial session at the Transcatheter Cardiovascular Therapeutics (TCT) 2024 conference in Washington, DC, on Wednesday. “I’m a little disappointed,” said Roxana Mehran, MD, moderator of a news conference Wednesday at TCT. “Me too, we need more valves in the arena,” said Dr. Reardon, replying to Dr. Mehran at the news conference. Over 60 countries outside the US have the ACURATE neo2 aortic valve system (Boston Scientific) available, and over 80,000 patients around the globe have been treated with this system. Investigators in the ACURATE IDE trial compared the ACURATE neo2 valve to select commercially available balloon-expandable or self-expanding devices. The balloon-expandable devices were SAPIEN 3 (Edwards) or newer, and the self-expanding devices were Evolut (Medtronic) or newer. The ACURATE IDE trial was a prospective, multicenter, randomized study with a total of 1,500 patients assigned 1:1 to ACURATE neo2 (n=752) or mixed control (n=748). The primary endpoint was a composite of all-cause mortality, stroke or rehospitalization at 1-year. The non-inferiority tests revealed that the primary endpoint was not met. Kaplan-Meier analysis at 1-year showed ACURATE neo2 patients had higher rates of the primary endpoint (14.8%) compared with the control group (9.1%) (95% CI=2.4-9.1). A post-hoc case review of ACURATE neo2 examined the stent expansion using angiographic imaging. Non-parallel commissure posts identified under-expansion of the stent. Roughly 20% of ACURATE neo2 cases had valve frame under-expansion. These cases had turbulent flow and reduced washout due to the under-expanded stent. Additionally, an increased rate of stroke (3-fold; p<0.001) and death (2-fold, 0.054) was noted in cases with under-expanded valves. The time-to-event analysis through 1-year post-procedure included 553 ACURATE neo2 patients with expanded valve frames and 150 with under-expanded valve frames (primary endpoint=12.4% versus 18.8%, p=0.050). In ACURATE neo2 patients with expanded stents, death and stroke rates at 1-year were comparable to the control group (ACURATE neo2 deaths=3.7%, stroke=3.5%; control deaths=3.6%, stroke=3.4%). Overall, in patients with severe AS, under-expanded ACURATE neo2 valves were associated with higher rates of death and stroke at 1-year, compared with the control group. The control patients and well-expanded stents in the ACURATE neo2 group had comparable death and stroke outcomes at 1-year. Image Caption: Michael J. Reardon, MD, speaks during a news conference Wednesday at the Transcatheter Cardiovascular Therapeutics (TCT) conference in Washington, DC. Image Credit: Bailey G. Salimes, CRTonline.org