LAUSR

Editorial for “Global Aortic Pulse Wave Velocity in Bicuspid Aortopathy Similar to Controls but Elevated With Aortic Valve Stenosis” It is well known that bicuspid aortic valve (BAV) is a common type of adult congenital heart disease, with an incidence of 0.5% to 1.4%. Evidence shows that the form of aortic dilation that occurs in patients with BAV is variable, with heterogeneous molecular mechanisms, hemorheology, and clinical characteristics. To date, it remains an in-depth exploration of how complications arise in patients with BAV. Questions remain about how to measure the relationship between altered wall structure and BAV-mediated hemodynamics. Catheter measurement is regarded as the gold standard for assessing the development of aortic pressure waves, but published studies have provided preliminary evidence of a role for pulse wave velocity (PWV) in evaluating blood flow based on flow waveform measurements in either single 2-dimensional (2D) planes or using other techniques that transect the aorta. Despite the efforts of many researchers who have investigated global aortic PWV in patients with bicuspid aortopathy (vascular stiffness), using 2D or 3D flow magnetic resonance imaging (MRI), techniques for investigating global aortic PWV in bicuspid aortopathy still have limitations. Therefore, the 4D MRI data PWV has been proposed as a tool for evaluating bicuspid aortopathy. The 4D MRI data PWV calculation with full volumetric coverage may be an advantage over standard 2D or 3D techniques for the oftendistorted route of the aorta in patients with atherosclerosis. In this issue of JMRI, Johnson et al describe the use of a PWV methodology based on 4D flow MRI as a surrogate method of analysis for aortic stiffness. The researchers found that the severity of aortic stenosis and patient age were directly associated with increased PWV. The authors came to the following significant conclusions: 1) older age in groups of patients with BAV and normal tricuspid aortic valves is significantly correlated with elevated PWV; 2) minimal differences exist between patients with nonstenotic BAV and either healthy individuals or patients with nonstenotic tricuspid aortic valves. The conclusions of this study have significant value for clinical application. However, 4D flow MRI with low temporal resolution only detects flow transit times over shorter segments of the aorta, and the local stiffness measurement cannot be fully used to accurately analyze and understand the changes between local blood flow and stiffness. Further study with a large cohort may improve our understanding of the relationship between altered flow and altered vessel biomechanics.