Patients at low surgical risk who had undergone transcatheter aortic valve implantation (TAVI) for bicuspid aortic stenosis had no significant difference in mortality or stroke at 30 days or one year compared to those who had undergone TAVI for tricuspid aortic stenosis.
This was the finding of a registry-based cohort study comparing outcomes of TAVI using the Sapien 3 and Sapien 3 Ultra (Edwards Lifesciences) balloon-expandable valve, published online in the Journal of the American Medical Association (JAMA), aimed at addressing the “limited” data on outcomes of TAVI for bicuspid aortic stenosis.
“In carefully selected, low-risk patients, this minimally invasive TAVI procedure may be beneficial,” said Raj Makkar, vice president of Cardiovascular Innovation and Intervention at Cedars-Sinai (Los Angeles, USA), the study’s lead author. “We are in the midst of a transcatheter heart valve revolution and expect this particular procedure to become more and more commonplace with each passing year.”
The study’s primary outcomes were the rates of death and stroke at 30 days and one year. The secondary outcomes included procedural and in-hospital outcomes, echocardiographic outcomes, functional status (New York Heart Association [NYHA] heart failure class), and health status (the Kansas City Cardiomyopathy Questionnaire overall summary [KCCQ-OS] score; score range, 0–100 [higher scores indicate less symptom burden and better quality of life]).
A total of 3,168 propensity-matched pairs of patients, at low surgical risk, undergoing TAVI for bicuspid versus tricuspid aortic stenosis who underwent TAVI at 684 US centres were included in the study. Participants were enrolled in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapies (TVT) registry from June 2015 to October 2020. Among 159,661 patients (7,058 bicuspid, 152,603 tricuspid), 37,660 patients (3,243 bicuspid and 34,417 tricuspid) who were at low surgical risk (defined as STS risk score <3%) were included in the analysis.
Among the propensity-matched patients (mean age, 69 years; 69.8% men; mean [SD] STS-predicted risk of mortality, 1.7% [0.6%] for bicuspid and 1.7% [0.7%] for tricuspid), Makkar and colleagues found that there was no significant difference between the bicuspid and tricuspid groups’ rates of death at 30 days (0.9% vs. 0.8%; hazard ratio [HR], 1.18 [95% confidence interval [CI], 0.68‒2.03]; p=0.55) and at one year (4.6% vs. 6.6%; HR, 0.75 [95% CI, 0.55‒1.02]; p=0.06) or stroke at 30 days (1.4% vs 1.2%; HR, 1.14 [95% CI, 0.73‒1.78]; p=0.55) and at one year (2% vs. 2.1%; HR 1.03 [95% CI, 0.69‒1.53]; p=0.89).
The study team found that there were no significant differences between the bicuspid and tricuspid groups in procedural complications, valve haemodynamics (aortic valve gradient: 13.2mmHg vs. 13.5mmHg; absolute risk difference [RD], 0.3mmHg [95% CI, -0.9–0.3 mm Hg]), and moderate or severe paravalvular leak (3.4% vs. 2.1%; absolute RD, 1.3% [95% CI, -0.6–3.2%]).
Discussing the findings in JAMA, Makkar et al note that this is the first report from the STS/ACC registry on outcomes in low-risk TAVI patients with bicuspid aortic stenosis. “There are currently no ongoing randomised trials of TAVI versus surgery for the treatment of bicuspid aortic stenosis,” they note. “Given the paucity of data, patients with bicuspid aortic stenosis, especially those at low surgical risk, are often considered more suitable for surgery.”
Makkar and colleagues write that the findings of their analysis suggest that bicuspid TAVI outcomes are comparable with published surgical series on bicuspid aortic stenosis and reported 30-day mortality ranging from 0.4–2.5% in younger patients with a mean age of 55–61 years.
They add that prior reports from the same registry in patients at higher surgical risk have reported higher rates of stroke, paravalvular regurgitation, and permanent pacemaker implantation after TAVI in patients with bicuspid aortic stenosis. In the present study of patients at low surgical risk and low risk of severe aortic stenosis, the rates of stroke, paravalvular regurgitation, and permanent pacemaker implantation were not significantly different between patients with bicuspid versus tricuspid aortic stenosis. Possible explanations for this, they note, include better patient selection due to availability of surgical alternative in patients at low surgical risk, evolution of device technology (fourth-generation balloon-expandable transcatheter heart valves associated with decreased paravalvular regurgitation), and procedural technique (higher valve implantation associated with decreased pacemaker rates).
“Our hope is for this data to translate into better advocacy and decision-making among healthcare providers and patients diagnosed with bicuspid aortic stenosis,” said Makkar. “By carefully selecting low-risk surgical patients with bicuspid aortic stenosis, we can add years to life and life to years.”
