Abstract Body (Do not enter title and authors here): Background:
Recent data demonstrated a temporal increase in adoption of transcatheter aortic valve replacement (TAVR) for treating aortic stenosis (AS) across all age groups. Whether there is a differential trend in adoption of TAVR vs. surgical AVR (SAVR) according to valve type, i.e., bicuspid (BAV) vs tricuspid aortic valve (TAV), is unknown.

Methods:
The Vizient Clinical Database was queried to identify patients who underwent TAVR vs SAVR between October 2015 and November 2023. Patients who underwent AVR for aortic regurgitation or underwent concomitant surgery during SAVR were excluded. The final cohort was divided according to the valve type into BAV and TAV cohorts. National trends in TAVR vs SAVR were examined overall and across BAV and TAV cohorts stratified by different age groups (<65, 65-80, >80 years) using linear regression analysis. Logistic regression analyses were performed to examine if age and valve type are predictors of TAVR use.

Results:
Among 365,985 patients who underwent isolated AVR for AS, 248,697 (67.95%) underwent TAVR. BAV was present in 42,754 (11.7%) of the final cohort and was treated with SAVR in 85% of patients. Across all age groups, there was an uptrend in the overall use of TAVR and among both BAV and TAV cohorts. The relative rise in all TAVR use was highest in patients <65 years (157%) and in TAVR for BAV was highest in patients 65-80 years (493.93%). In 2023, SAVR was the main AVR modality in all patients <65 years (76.80%), while TAVR was the main modality in patients >80 years (97.84%). In the BAV cohort, SAVR remained the main AVR modality in patients < 65 years (92.65%) and 65-80 years (69.47%), while TAVR was the main modality in patients >80 years (82.83%). In logistic regression analysis, patients 65-80 years and >80 years were more likely to receive TAVR than younger patients <65 years, and BAV patients were less likely to receive TAVR compared to TAV patients (p < 0.05 for all).

Conclusion:
TAVR is increasingly adopted across all age group and is more commonly performed for tricuspid vs bicuspid AS. Per these contemporary national trends, SAVR remains the main AVR modality in all patients <65 years, and in BAV patients <80 years, while TAVR remains the main AVR modality in all patients > 80 years.