There are differences in bicuspid aortic valve (BAV) characteristics between Asian
and European populations, but little is known about the inter-ethnic differences in
bicuspid valve function and aortic root dimensions within the diverse Asian population.
From 1992–2017, 562 patients with index echocardiographic diagnosis of BAV in a tertiary
health care institution in Singapore were analysed according to their ethnic groups:
Chinese, Malay, Indian, and Eurasian. Study outcomes included BAV complications (infective
endocarditis, aortic dissection) and clinical outcomes (aortic valve surgery, aortic
root surgery, all-cause mortality). Total events were defined as composite outcome
of all BAV complications and outcomes. Aortic dimensions and aortic dilatation rates
were also studied.
There were 379 (67.5%) Chinese, 79 (14.0%) Malay, 73 (13.0%) Indian, and 31 (5.5%)
Eurasian patients. Type 1 BAV (58.5%) was the most prevalent BAV morphology, with
moderate-to-severe aortic stenosis (AS) (36.8%) being the most common complication
in the overall population. There was a higher prevalence of type 0 BAV in Chinese
and Indian groups, and type 1 BAV with fusion of left-right coronary cusp in Eurasian
and Malay groups (p=0.082). There was no difference in significant AS among groups.
The highest prevalence of moderate-to-severe aortic regurgitation was observed amongst
the Eurasian group, followed by Chinese, Indian, and Malay groups (p=0.033). The Chinese
group had the largest mean indexed diameters of the aortic root. Multivariable linear
regression demonstrated that only the Chinese had significantly larger indexed diameters
in the aortic annulus, sinotubular junction (STJ), and ascending aorta (AA), relative
to the Eurasian group, after adjusting for age, sex, smoking, hypertension, hyperlipidaemia,
diabetes, and aortic regurgitation. On follow-up echocardiography, there was a trend
towards the highest dilatation rates of sinus of Valsalva and STJ amongst Indian,
and AA amongst Malay groups. Kaplan-Meier curves showed the highest incidence of total
events amongst Chinese, followed by Malay, Indian and Eurasian (log-rank=9.691; p=0.021)
There were differences in BAV morphology, valve dysfunction, aortopathy, and prognosis
within the Asian population. Chinese patients had one of the highest prevalence of
significant aortic regurgitation, with the largest aortic dimensions and worst outcomes
compared with other Asian ethnicities. Closer surveillance is warranted in BAV patients
within the Asian population.