Anatomical Determinants and Outcomes of Small Annulus Patients Undergoing TAVR in Different ASIAN Ethnicity

Transcatheter aortic valve implantation (TAVI) presents unique challenges for Asian patients compared to Caucasians, largely due to the prevalence of small aortic annulus (SAA) defined based on Caucasians' data (430 mm²), bicuspid aortic valve (BAV), and substantial calcium deposits. No universally accepted cutoff value for defining SAA exists among Asian patients, who tend to have smaller body-built, resulting in inconsistencies across various studies. For the new-generation 20-/23-mm balloon expandable valve, a SAA is categorized as <330 mm². Additionally, Asian Japanese patients have been identified to have extremely SAA (<314 mm²), associated with unexpectedly larger residual transvalvular gradients following TAVI.

Previous research on patient prosthesis mismatch (PPM) impact within the Asian population has also shown inconsistency. The OCEAN-TAVI registry with 1,546 Japanese patients found no significant differences in one-year all-cause and cardiovascular mortality between PPM and non-PPM groups. A study on the Sapien 3 balloon expandable valve in patients with SAA (<430 mm²) found comparable clinical outcomes to non-SAA patients up to five years post-procedure, consistent with findings from a South Korean study. However, a Taiwan study involving 201 patients with PPM indicated higher rates of adverse outcomes at mid-term follow-up. Moreover, TAVI with self-expanding valves (SEV) has shown improved hemodynamic outcomes and reduced PPM incidence compared to balloon expandable valves (BEV) in patients with extreme SAA.

To date, research on inter-racial differences in TAVI among Asian populations is lacking. This multicenter registry aims to evaluate SEV versus BEV outcomes in diverse Asian patients, particularly those with extreme SAA, and to address ethnic-specific challenges in TAVI.