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People with bicuspid aortic stenosis had an early disadvantage for stroke after getting transcatheter aortic valve replacement (TAVR) with a balloon-expandable valve, researchers found from the TVT Registry.

Whereas post-TAVR mortality rates were similar between Sapien 3 recipients with two- and three-leaflet anatomy, early stroke was more common with bicuspid valves before reaching statistical equivalency at 1 year:

• 30-day mortality: 2.6% vs 2.5% (HR 1.04, 95% CI 0.74-1.47)
• 1-year mortality: 10.5% vs 12.0% (HR 0.90, 95% CI 0.73-1.10)
• 30-day stroke: 2.5% vs 1.6% (HR 1.57, 95% CI 1.06-2.33)
• 1-year stroke: 3.4% vs 3.1% (HR 1.28, 95% CI 0.91-1.79)

The bicuspid group also experienced significantly more procedural complications requiring open heart surgery (0.9% vs 0.4%), according to a group led by Raj Makkar, MD, of Cedars-Sinai Medical Center in Los Angeles, in a preliminary report in the June 11 issue of .

The paper emphasized the 30-day excess in strokes with bicuspid valves, whereas the 1 year similarities were the focus when Makkar and colleagues initially reported these outcomes at the American College of Cardiology meeting in March.

"Because of the potential for selection bias and the absence of a control group treated surgically for bicuspid stenosis, randomized trials are needed to adequately assess the efficacy and safety of transcatheter aortic valve replacement for bicuspid aortic stenosis," the authors said.

Nevertheless, they suggested the use of embolic protection devices to potentially reduce TAVR-related strokes among people who have bicuspid anatomy.

"TAVR for bicuspid aortic stenosis presents both anatomic and clinical challenges. The concern for suboptimal valve expansion in an orifice with 2 commissures (in lieu of 3 commissures) and the resultant paravalvular regurgitation was the main reason for exclusion of bicuspid aortic stenosis from TAVR trials," they noted.

Even the landmark low-risk trials reported this year excluded patients with bicuspid anatomy, Makkar's group added.

"In addition, these valves are often heavily calcified, accompanied by raphe (fusion between adjacent cusps) and have concomitant aortopathy (dilatation of the ascending aorta), which may require additional surgical treatment of the aorta," according to the authors.

Complicating things further is the question of whether a randomized trial can now even be conducted properly, commented Colin Barker, MD, of Vanderbilt University in Nashville, Tennessee, and Michael Reardon, MD, of Houston Methodist Hospital, in an .

"For instance, 4 years ago a randomized trial comparing surgery vs TAVR among patients with bicuspid aortic valve with severe aortic stenosis would have been possible and highly informative. Today, however, there may be concerns about the ability to enroll any patients other than those at low-risk. Even then, the target population for randomization would be younger patients (for whom less data on TAVR are available) and even that will likely be difficult," the editorialists wrote.

Makkar and colleagues collected data on 81,822 TAVR patients getting the Sapien 3 device at 552 U.S. centers in 2015-2018. Of almost all these consecutive patients, nearly 3% had bicuspid anatomy.

This subset of individuals showed greater need for the largest prostheses and, during their procedures, suffered more conversion to surgery and annulus ruptures.

Outcomes were compared between groups via 2,691 propensity-score matched pairs that had comparable baseline characteristics. These patients had a median age of 74, and women accounted for 39.1%. The average Society of Thoracic Surgery-predicted risk of mortality was about 5% for both bicuspid and tricuspid arms.

The researchers noted no between-group differences in valve hemodynamics, paravalvular aortic regurgitation at 30 days and 1 year, nor improvement in quality of life at 1 year.

"The results of this study may not be applicable to all patients with bicuspid aortic stenosis, since the operators may have excluded patients with challenging anatomical features that may increase the risk of procedural complications," Makkar's group cautioned.

"Additionally, surgeons are well aware that different bicuspid aortic valve phenotypes carry differing risk of aortopathy (dilatation of the ascending aorta) that would be better treated with suggesting surgery as a better current option," according to Barker and Reardon.