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People with bicuspid anatomy had favorable outcomes following transcatheter aortic valve replacement (TAVR) with self-expanding transcatheter heart valves, according to data from the STS/ACC TVT Registry, which was created by a collaboration between the Society of Thoracic Surgeons and the American College of Cardiology.

Among 929 people with bicuspid aortic valve (BAV) stenosis matched to peers with tricuspid anatomy, TAVR with the Evolut R or Evolut PRO -- the latter of which has an additional outer pericardial wrap to decrease paravalvular leak -- resulted in similar rates of:

• All-cause mortality at 30 days: 2.6% vs 1.7% (P=0.18)

• All-cause mortality at 1 year: 10.4% vs 12.1% (P=0.63)

• Stroke at 30 days: 3.4% vs 2.7% (P=0.41)

• Stroke at 1 year: 3.9% vs 4.4% (P=0.93)

Bicuspid TAVR was associated with no significant increase in pacemaker implants (14.3% vs 12.4%, P=0.22) and achieved the same "excellent" hemodynamics as seen in tricuspid anatomy, reported a group led by John Forrest, MD, of Yale University School of Medicine in New Haven, Connecticut.

"In patients at increased surgical risk, TAVR for bicuspid aortic valve stenosis indicates acceptable safety outcomes with low complication rates," the researchers concluded in their study published online in .

However, more patients in the bicuspid group required aortic valve reintervention at both 30 days (0.8% vs 0.1%, P=0.03) and 1 year (1.7% vs 0.3%, P=0.01).

The uptick in aortic valve reintervention could be attributed in part to an increased incidence of post-procedure moderate or severe aortic regurgitation after bicuspid TAVR (5.6% vs 2.1%, P<0.001). People who received the Evolut PRO valve had significantly less aortic regurgitation, the investigators noted.

An elevation in aortic regurgitation "suggests that there is still room to further improve and refine the technology to achieve greater safety and efficiency of TAVR in BAV stenosis," commented Didier Tchetche, MD, and Saifullah Siddiqui, MD, both of Clinique Pasteur in Toulouse, France, writing in an .

"Overall, we have observed within recent years a strong enthusiasm about TAVR as a strategy for BAV. Several reports confirm the feasibility of TAVR in BAV with satisfying short-to-mid-term outcomes," Tchetche and Siddiqui added.

For example, another registry study had shown that people with bicuspid anatomy had no difference in mortality 30 days or 1 year after TAVR with the Sapien 3 valve. Unlike Forrest and colleagues, however, that group had found a slightly higher incidence of stroke at 30 days post-TAVR compared with tricuspid peers, although this difference was no longer significant at 1 year.

"With greater experience the technical approach to TAVR in BAV has become more mature to include recommendations for balloon valvuloplasty before prosthesis deployment, avoidance of aggressive oversizing in relation to the aortic annulus diameter or the supra-annular sizing, and slow-paced deployment," the editorialists wrote.

But who exactly is a good candidate for TAVR in bicuspid anatomy? Is the aortic root anatomy the main factor for decision-making or should age be the deciding factor? These are among the questions that remain unanswered in this field, Tchetche and Siddiqui said.

Forrest's team had identified 932 patients with BAV stenosis who underwent elective TAVR in 2015-2018 according to the .

The researchers found that compared with patients getting TAVR on tricuspid valves during the same period (n=26,154), the bicuspid group was younger and had fewer cardiac comorbidities and lower STS scores at baseline. Moreover, the bicuspid group tended to start out with larger annular size and higher mean aortic valve gradients.

Propensity matching led to 929 matched pairs. The two groups were well matched except that bicuspid patients had a slower gait and were less likely to have a "hostile" mediastinum, Forrest and co-authors noted.

Bicuspid TAVR was associated with longer procedure times (113.6 vs 105.1 min, P=0.001), and fewer than 30% of those matched had received the Evolut PRO during TAVR.

Both the bicuspid and tricuspid groups had significant improvements in quality of life, as assessed by changes in Kansas City Cardiomyopathy Questionnaire scores and New York Heart Association classification, the researchers reported.

They noted that the registry study was limited by its retrospective and observational nature. In addition, the registry data had been self-reported without adjudication, and there was no stratification by Sievers Classification of bicuspid valve type. Furthermore, many patients had insufficient follow-up, with a median duration of just 79.0 days for the bicuspid group and 168.0 days for the tricuspid group.

"As the indications for TAVR have expanded to now include low-risk patients, and given that up to 50% of low-risk patients undergoing AVR are known to have bicuspid aortic valve disease, heart teams across the United States are much more likely to have patients with bicuspid aortic valve disease referred for evaluation than they were previously," Forrest and colleagues noted.

Randomized studies evaluating TAVR in low-risk patients with bicuspid aortic valve disease are needed, the team urged.

"It will be very important to continue to monitor these patients to see how the valves perform in 10 or 15 years," Forrest said in an ACC press release.

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