Quantitative assessment of microstructural damage in paediatric aortic coarctation tissue during benchtop balloon angioplasty and stenting

Endovascular stenting of native coarctation of the aorta (CoA) has become the standard treatment for children and young adults due to its less invasive nature and faster recovery times. Despite these advantages, neonatal CoA is still surgically treated, owing to the challenges of vessel growth and limited available stent designs. Plain old balloon angioplasty (POBA) of neonatal coarctation has been used in the past but concern around vessel damage and aneurysm formation has limited its widespread adoption. To-date, stenting has often been preferred over POBA in other anatomies, but little evidence has been gathered to establish the degree of tissue damage during intravascular procedures in neonatal CoA. The aim of this ex vivo study was to perform balloon angioplasty and stenting on neonatal CoA samples harvested from surgery and visualise the deformation under ultrasound guidance. Collagen hybridizing peptide (CHP) was used to assess the level of collagen damage in the tissue following these procedures. The results demonstrate that balloon angioplasty alone is not a viable treatment option for maintaining vessel patency unless very high levels of stretch are achieved to permanently deform the tissue. Five out of six neonatal coarctation samples were successfully stented with no stent failures, showing that stent insertion is a viable option to achieve the desired lumen diameter. Both procedures, however, induced considerable collagen damage. Overall, this study shows that stenting CoA tissue can achieve the desired lumen gain, however, a staged approach to stent expansion may be preferred to reduce collagen damage in the tissue.