Prognostic Implications of Bicuspid and Tricuspid Aortic Valve Phenotype on Progression of Moderate Aortic Stenosis and Ascending Aorta Dilatation

Chew NWS, Phua K, Ho YJ, Zhang A, Lin N, Ngiam JN, Lau YX, Teo VXY, Sia CH, Loh PH, Kuntjoro I, Wong RCC, Lee CH, Tan HC, Yeo TC, Kong WKF, Poh KK.Am J Cardiol. 2021 Dec 15;161:76-83. doi: 10.1016/j.amjcard.2021.08.050. Epub 2021 Oct 6.PMID: 34627597


Take Home Points:

  • Compared to patients with tricuspid aortic valves with a comparable degree of stenosis, patients with bicuspid aortic valve stenosis are younger and have larger aortic dimensions.
  • Over time, these patients have a comparable rate of progression of hemodynamics and aortic dimensions.
  • There was no significant difference in the rate of all-cause mortality, heart failure admission, or aortic valve replacement between these two groups.

Commentary from Dr. MC Leong (Kuala Lumpur), section editor of ACHD Journal Watch:

Bicuspid aortic valve (BAV) is the commonest congenital valvular abnormality. It is associated with aortic valve stenosis, incompetency and importantly aortopathy, manifested by dilatation of the ascending thoracic aorta. Progressive dilatation of the ascending aorta may lead to dissection of the aorta unless timely aortic root dilatation is carried out. This study examined the differences in the anatomic and hemodynamic progression of patients with moderate bicuspid aortic stenosis and its rate of ascending aortic dilatation using patients with tricuspid aortic valve (TAV) as control.


This was a single-center, retrospective study involving 288 patients (mean age: 67 ± 15 years, male: 46.5%) with at least 1 year of echocardiographic follow-up. The study defined moderate aortic stenosis (AS) as an aortic valve area of 1.0-1.5cm2while severe AS was defined as an aortic valve area < 1.0cm2. Meanwhile, rapid ascending aortic (AA) progression was defined as AA dilatation rate ≥+0.50 mm/year. All measurements were made on echocardiogram.


Baseline demographics were shown in Table 1. At baseline, no difference was seen in the severity of the aortic valve stenosis between the BAV and TAV groups. Patients in the BAV groups were younger and had larger aortic root dimensions at baseline. Over the period of 1 year, the progression of the aortic valve stenosis and aortic dimensions were comparable between the groups (Table 2). After 1 year, hemodynamics changes were again, not significantly different between the groups. However, there was a trend toward a higher prevalence of rapid progressors of AA dilatation in the BAV group (p= 0.099).


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The mean follow-up duration was 58.2 ± 40.7 months. During the follow-up period, the authors found a trend toward a higher incidence of aortic valve replacement in the BAV group (27.5%) compared with the TAV group (17.3%, p = 0.053). Those who progressed to severe AS were of younger and were more likely to require aortic valve replacement (Table 4). BAV was not found to be an independent predictor of all-cause mortality, heart failure admission, or aortic valve replacement in multivariate analyses. There were initially a lower freedom of aortic valve replacement and a higher mortality rate in the BAV group, in the Kaplan-Meier curve analyses. However, in the adjusted Kaplan-Meier curves, there were no statistically significant differences in heart failure admissions, aortic valve replacement, or all-cause mortality between the groups (Figure 1).


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The study highlighted a few salient points: (1) although there was no difference in baseline hemodynamics, patients with BAV had larger aortic root dimensions; (2) over time, there was no difference in the progression of the aortic valve severity between the BAV and TAV groups; and (3) patients with BAV were not at an increased risk of aortic valve replacement (even though the trend suggested so), heart failure and mortality. Patients with BAV may have progression of aortic dilatation at a rate comparable to those with TAV, but they progressed from a larger dimension at baseline and at a younger age underscoring the importance of close surveillance in this particular group of patients. One of the flaws of this study lies in the fact that the aortic dimensions were performed using echocardiogram rather than CT or MRI scans, which were known to have a lower rate of measurement errors (ref).



  1. Kebed K, Sun D, Addetia K, Mor-Avi V, Markuzon N, Lang RM. Measurement errors in serial echocardiographic assessments of aortic valve stenosis severity. Int J Cardiovasc Imaging. 2020;36(3):471-479.