Balloon, Self-Expanding TAVI Devices Provide Similar Results in Bicuspid Valves

For patients with bicuspid aortic valve stenosis who undergo TAVI, rates of death or stroke are similar at 3 years, as well as in the hospital and at 30 days, regardless of whether they receive a balloon-expandable or self-expanding device, newly released registry data suggest.

However, there were some differences early on: balloon-expandable transcatheter heart valves (THVs) were linked to both higher transvalvular mean gradient and more frequent annulus rupture, while self-expanding THVs were linked to more frequent moderate-to-severe aortic regurgitation and use of additional THVs, as well as a higher risk of permanent pacemaker implantation.

The results were published online earlier this month in Circulation.

Lead investigator Daniele Giacoppo, MD, PhD (University of Catania, Italy, and Mater Private Hospital, Dublin, Ireland), highlighted the fact that approximately 0.5 to 2% of the population is born with a bicuspid aortic valve. People with this anatomy are more likely to develop aortic stenosis over their lifespan, “generally 10 to 20 years earlier than in patients with tricuspid aortic valves,” a timeline that’s become more relevant as TAVI has extended to younger individuals, he said. As this broader shift has occurred, so too has the prevalence of bicuspid anatomy being seen at high-volume TAVI centers, which now exceeds 10%.

Yet, to date, “almost all randomized trials comparing transcatheter aortic valve replacement with surgical aortic valve replacement, including the more recent PARTNER 3, Evolut Low Risk, and DEDICATE-DZHK6, have systematically excluded patients with bicuspid valves because of anatomical and technical concerns,” Giacoppo told TCTMD. Also lacking are studies showing which THV type is best for use in bicuspid anatomy.

Firas Zahr, MD (Oregon Health & Science University, Portland), commenting on the paper for TCTMD, described bicuspid aortic valves as a “hot topic.”

It’s still unclear whether transcatheter or surgical aortic valve replacement is the best choice in this patient subset, he noted. “That question is still not a hundred percent answered. And of those who get treated with TAVR, [should] they get treated with balloon-expandable versus self-expanding? That question is also not a hundred percent answered.”

The current report is reassuring, said Zahr, but its findings may not apply to younger, low-risk patients. “The mean age was still patients in their 70s, . . . and the average STS score was greater than 3,” he noted. Additionally, even with the precautions taken by the researchers to adjust for baseline differences, as with any observational study there is the possibility of bias, Zahr pointed out.

When the topic is bicuspid aortic valves, selection bias might arise, he explained. “There are no universal selection criteria for those patients. An operator has agreed to treat them for whatever reason, and they agreed to treat them with either balloon or self-expanding.”

Choosing to do TAVI in the first place, then choosing which valve type to use, “ is quite complicated,” Zahr stressed. “It’s a multidisciplinary decision. It usually relies on the anatomy, the sizing, the calcium, the type of bicuspid, the state of the aortic valve, and if there is an indication for concomitant surgery.” For younger patients, durability and the possibility of future reinterventions also come into play, he said, noting that less is known about these concerns in bicuspid versus tricuspid aortic valves.

With all those intricacies in mind, this study “calls out the importance of digging deep into details” of what should drive decision-making, as well as the need for heart team input, said Zahr.

Three-Year Outcomes Similar

The retrospective analysis looked at 1,443 consecutive patients (median age 78.7 years; 39.4% women; median STS-PROM score 3.2%) with bicuspid aortic valve stenosis who underwent TAVI across 29 centers between May 2007 and December 2021. Sixty percent received balloon-expandable THVs and 40% got self-expanding.

Giacoppo and colleagues performed propensity-score matching and various other statistical methods to account for baseline differences. Rates of death or stroke, the composite primary endpoint, did not significantly differ between the two valve types.

Bicuspid Aortic Valves: Rates of Death or Stroke by TAVI Type

For death or stroke, outcomes were consistent across various clinical, anatomical, functional, and procedural characteristics.

Yet, after the procedure, patients with balloon-expandable devices had a higher risk of annulus rupture (1.3% vs 0.5%) and higher mean transvalvular gradient (10.0 vs 8.0 mm Hg). By 30 days, they were less apt to have received a permanent pacemaker (11.9% vs 18.6%). Patients with self-expanding devices, on the other hand, more often had additional valves implanted (5.3% vs 1.3%) and had more moderate/severe paravalvular regurgitation (13.1% vs 3.3%).

Giacoppo said that while the data overall indicate both valve types are effective in this population, the imbalance for some complications could help sway decision-making in certain patients, such as those with calcified bicuspid valves or smaller annular dimensions.

Both physicians who spoke with TCTMD called for randomized controlled trials pitting TAVI against SAVR in patients with bicuspid anatomy, something that might prove tricky because  not all bicuspid valves are alike. Such a trial would be worth doing, given data from the NOTION-2 trial hinting that surgery may be safer than a transcatheter approach in bicuspid valves, said Giacoppo. “This comparison should take priority.”

In the meantime, registries will continue to provide follow-up, enabling better understanding of how these patients fare over the years.

“I think the longer follow-up will tell us if what we’re doing is right or we need to adjust our strategy,” Zahr said. On top of this, “more and more real-life data is coming out in support of the use of TAVR in bicuspid. None of it gives us a free range to treat all bicuspid valves [this way], but a lot of it supports the use of TAVR in select patients with bicuspid aortic valve disease.”