Aortic dilation in bicuspid aortic valve disease: Flow pattern is a major contributor and differs with valve fusion type

Malenka M. Bissell, Aaron T. Hess, Luca Biasiolli, Steffan J. Glaze, Margaret Loudon, Alex Pitcher, Anne Davis, Bernard Prendergast, Michael Markl, Alex J. Barker, Stefan Neubauer, Saul G. Myerson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

286 Scopus citations


Background-Ascending aortic dilation is important in bicuspid aortic valve (BAV) disease, with increased risk of aortic dissection. We used cardiovascular MR to understand the pathophysiology better by examining the links between 3-dimensional flow abnormalities, aortic function, and aortic dilation. Methods and Results-A total of 142 subjects underwent cardiovascular MR (mean age, 40 years; 95 with BAV, 47 healthy volunteers). Patients with BAV had predominantly abnormal right-handed helical flow in the ascending aorta, larger ascending aortas (18.3±3.3 versus 15.2±2.2 mm/m2; P<0.001), and higher rotational (helical) flow (31.7±15.8 versus 2.9±3.9 mm2/s; P<0.001), systolic flow angle (23.1°±12.5° versus 7.0°±4.6°; P<0.001), and systolic wall shear stress (0.85±0.28 versus 0.59±0.17 N/m2; P<0.001) compared with healthy volunteers. BAV with right-handed flow and rightnon coronary cusp fusion (n=31) showed more severe flow abnormalities (rotational flow, 38.5±16.5 versus 27.8±12.4 mm2/s; P<0.001; systolic flow angle, 29.4°±10.9° versus 19.4°±11.4°; P<0.001; in-plane wall shear stress, 0.64±0.23 versus 0.47±0.22 N/m2; P<0.001) and larger aortas (19.5±3.4 versus 17.5±3.1 mm/m2; P<0.05) than right-left cusp fusion (n=55). Patients with BAV with normal flow patterns had similar aortic dimensions and wall shear stress to healthy volunteers and younger patients with BAV showed abnormal flow patterns but no aortic dilation, both further supporting the importance of flow pattern in the pathogenesis of aortic dilation. Aortic function measures (distensibility, aortic strain, and pulse wave velocity) were similar across all groups. Conclusions-Flow abnormalities may be a major contributor to aortic dilation in BAV. Fusion type affects the severity of flow abnormalities and may allow better risk prediction and selection of patients for earlier surgical intervention.

Original languageEnglish (US)
Pages (from-to)499-507
Number of pages9
JournalCirculation: Cardiovascular Imaging
Issue number4
StatePublished - Jul 2013


  • Aorta
  • Bicuspid aortic valve
  • Cardiac MRI
  • Vascular function
  • Wall shear stress

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine


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