Background and aims: Transcatheter aortic valve implantation (TAVI) has become the first choice to treat older patients with severe symptomatic aortic stenosis (AS). This study aimed to compare TAVI with surgery in low-risk patients ≤ 75 years of age, including both tricuspid and bicuspid AS.

Methods: The NOTION-2 trial enrolled and 1:1 randomized low-risk patients aged ≤ 75 years with severe symptomatic AS to TAVI or surgery. The primary endpoint was a composite of all-cause mortality, stroke or rehospitalization (related to the procedure, valve or heart failure) at 12 months.

Results: A total of 370 patients were enrolled with a mean age of 71.1 years and a median Society of Thoracic Surgeons risk score of 1.1%. A total of 100 patients had bicuspid AS. The 1-year incidence of the primary endpoint was 10.2% in the TAVI group and 7.1% in the surgery group (absolute risk difference 3.1%; 95% confidence interval [CI], -2.7% to 8.8%; hazard ratio (HR) 1.4, 95% CI: 0.7 to 2.9; p=0.3). Patients with TAVI, when compared to surgery, had lower risk of major bleeding and new-onset atrial fibrillation and higher risk of non-disabling stroke, permanent pacemaker implantation and moderate-or-greater paravalvular regurgitation. The risk of the primary composite endpoint was 8.7% and 8.3% in patients with tricuspid AS (HR 1.0, 95% CI: 0.5 to 2.3) and 14.3% and 3.9% in patients with bicuspid AS (HR 3.8, 95% CI: 0.8 to 18.5) treated with TAVI or surgery, respectively (P for interaction=0.1).

Conclusions: Among low-risk patients aged ≤ 75 years with severe symptomatic AS, the rate of the composite of death, stroke, or rehospitalization at one year was similar between TAVI and surgery. TAVI outcomes in young bicuspid AS patients warrant caution and should be further investigated. (NOTION-2, ClinicalTrials.gov, NCT02825134).