4D-flow MRI derived wall shear stress for the risk stratification of bicuspid aortic valve aortopathy: A systematic review

Abstract

PurposeCurrent intervention guidelines for bicuspid aortic valve (BAV) associated ascending aorta (AAo) dilatation are suboptimal predictors of clinical outcome. There is growing interest in identifying better biomarkers such as wall shear stress (WSS) to help risk stratify BAV aortopathy. The aim of the systematic review is to synthesize existing evidence of the relationship between WSS and aortopathy in the BAV population.MethodsA comprehensive literature search of available major databases was performed in May 2022 to include studies that used four-dimensional flow cardiac magnetic resonance (4D-flow) MRI to quantify WSS in the AAo in adult BAV populations. Summary results and statistical analysis were provided for key numerical results. A narrative summary was provided to assess similarities between studies.ResultsA total of 26 studies that satisfied selection criteria and quality assessment were included in the review. The presence of BAV resulted in significantly elevated WSS magnitude and circumferential WSS, but not axial WSS. The presence of aortic stenosis had additional impact on WSS and flow alterations. BAV phenotypes were associated with different WSS distributions and flow profiles. Altered protein expression in the AAo wall associated with WSS supported the contribution of altered hemodynamics to aortopathy in addition to genetic factors.ConclusionWSS has the potential to be a valid biomarker for BAV aortopathy. Future work would benefit from larger study cohorts with longitudinal evaluations to further characterize WSS association with aortopathy, mortality, and morbidities.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022337077, identifier CRD42022337077.

Methods: Aortic wall deformation assessment by ultrafast ultrasound imaging: Application to bicuspid aortic valve associated aortopathy

“…Aortic wall alterations are indeed at least partly related to the flow constraints applied (Bollache et al, 2018). The use of wall shear stress measurement, as shown in 4D flow MRI (Guala et al, 2022;Kiema et al, 2022;Soulat et al, 2022;Qin et al, 2023), is thus particularly useful, although yet to be available with echocardiography. An appealing prospect is the use of ultrasound innovations in the field flow mapping to combine aortic wall markers, such as stiffness, and wall shear stress, to appreciate better the causative phenomena of aortic remodeling and aneurysmal progression (Cai et al, 2019;Kainuma et al, 2022).…”

Medical Radiology: Current Progress

“…MRA combined with 4D flow MRI offers an advantage over dynamic CTA in imaging the whole aorta with no radiation burden; however, its sensitivity in detecting endoleaks has yet to be determined, and further large-scale studies are necessary to determine its optimal use. Additionally, the 4D flow may underestimate WSS due to spatial resolution limitations [39]. The clinical use of 4D-flow MRI has become avaible only recently.…”

Medical Radiology in Italy: Current Progress

“…Additionally, assessments of wall shear stress, pulse-wave velocity, and pressure gradients can be performed alongside blood flow estimation. MRA combined with 4D flow MRI offers an advantage over dynamic CTA in imaging the whole aorta with no radiation burden; however, its sensitivity in detecting endoleaks has yet to be determined, and further large-scale studies are necessary to determine its optimal use (Qin et al, 2023).…”