Inter-ethnic heterogeneity in valvular morphology and aortopathy of a worldwide bicuspid aortic valve cohort referred for TAVR
Authors: Barki M , Lohani I L , Bhatt S B , Glauber M G , Guagliumi G G , Tespili M T , Ielasi A I 
Published: October 2024

Abstract

Background
Bicuspid aortic valve (BAV) represents one of the most common congenital heart disease. BAV stenosis tipycally occurs in younger, low-surgical risk patients compared to tricuspid aortic valves (TAV). With the predicted expansion of trans-catheter aortic valve replacement (TAVR) into lower-risk patients, the proportion of BAV is expected to rise. Although some observational studies have investigated the characteristics of Asian versus European patients with BAV undergoing TAVR, little is known about the inter-ethnic differences within the large and diverse Asian, African, Russian, and Caucasian population.

Purpose
To evaluate the inter-ethnic differences of aortic valve morphology, annular size and associated aortopathy, in a worldwide population of patients with severe aortic stenosis referred for TAVR.

Methods
Cardiovascular multislice computed tomography data of patients with severe aortic valve stenosis referred for TAVR worldwide were obtained from the database of the Meril Life Core Lab. Inter-ethnic and epidemiological differences in terms of valvular phenotype, annular size and aortic morphology were evaluated with particular focus on patients with BAV.

Results
Among 12,712 patients (59% male), n=3,203 subjects (25%) exhibited a BAV morphology. According to the Siever’s BAV classification, type 1 (71%, n=2,284) was the most prevalent BAV morphology and particularly Type 1a was the most common in almost all population, with 26% exhibiting a type 0 BAV, while only 3% of the patients (n= 92) had a type 2 (Table 1). A significantly higher prevalence of severe calcium score (&gt;1000 mm3) was found in patients with BAV compared with patients exhibiting a TAV morphology (51% vs. 32, p&lt;0.01). Additionally, larger ascending aorta (AA) diameter (AA &gt;40 mm) (BAV: 31% vs TAV 7%, p = 0.04), along with a higher prevalence of horizontal aorta (HA) (BAV: 20% vs TAV: 9%, p&lt;0.01) was found in patients with BAV compared with TAV. As for inter-ethnic characteristics, there was a higher prevalence of BAV in Indian and Asian Pacific populations (respectively 43% and 28%), with the African population exhibiting the lowest prevalence (7%, n= 28, p=0.02) (Table 2). In Indian patients a higher prevalence of BAV was found in an earlier age (61-70 years old) compared to Western countries (p=0.05).
Finally, smaller annular size (456±98 mm2 vs 584±99 mm2, p&lt;0.01) and lower coronary ostia height (Asia and India: RCA 14.5±3 mm, LCA 14±2.9mm vs Caucasian and Russian: RCA 16±3.2 mm, LCA 16.9±3.3mm; p&lt;0.01) were found in the Asian and Indian population when compared with Russian, African and Caucasian subjects.

Conclusions
BAV morphology, aortopathy and annular size resulted widely heterogenous according to the ethnicity and geographical origin of patients referred for TAVR worldwide. These features may lead different therapeutical decision making and outcomes following TAVR in patients with BAV.Table 1Table 2