Three-dimensional transoesophageal echocardiography of the aortic valve and root: changes in aortic root dilation and aortic regurgitation.

Aims: It has been hypothesized that in response to dilation of the aortic root, the aortic valve cusps may remodel to prevent aortic regurgitation (AR). The aim of the present study was to evaluate the association between aortic cusp dimensions and aortic root geometry.

Methods and results: Three-dimensional transoesophageal echocardiography was performed in 40 patients with aortic root dilation (mean age 57 ± 12 years, 75% men, 35% bicuspid aortic valve) and 20 controls with a normal aortic root (mean age 61 ± 13 years, 65% men). Aortic valve geometry was measured, and the ratio between closed cusp area and sinotubular junction (STJ) area as a measure of the aortic cusp remodelling relative to the aortic root dilation was assessed. Patients with aortic root dilation with tricuspid aortic valve (n = 26) showed significant increase in aortic cusp size. However, the closed cusp area to STJ area ratio was smaller in dilated aortic roots [0.88 (95% confidence interval: 0.78-0.98)] compared with normal aortic roots [1.22 (95% confidence interval: 1.02-1.41); P = 0.002]. In addition, in patients with central AR, there was insufficient cusp tissue, as suggested by a closed cusp area to STJ area ratio of 0.75 (95% confidence interval: 0.67-0.82), compared with relative excess of cusp tissue in eccentric AR with a ratio of 1.14 (95% confidence interval: 1.01-1.27; P < 0.001).

Conclusion: Aortic root dilation was associated with significant increase in aortic valve cusp size. However, this increase seemed insufficient to match aortic root size, particularly in central AR, whereas in eccentric AR, there was relative abundance of cusp tissue resulting in relative cusp prolapse.