Assessing microstructural damage in paediatric aortic coarctation tissue during benchtop balloon angioplasty and stenting

Endovascular stenting of native aortic coarctation has become standard treatment for children and young adults due to the shorter hospital stay and recovery time, lower procedural risk and less invasive nature. However, despite these advantages, neonatal coarctation remains a surgically treated lesion, owing to the challenges of vessel growth and stent design. Plain old balloon angioplasty (POBA) of neonatal coarctation has been used as a treatment modality in the past but concern around vessel damage and aneurysm formation limited its widespread adoption. To-date, stenting has often been preferred over POBA treatment to minimise tissue damage but very little evidence has been gathered to establish the degree of tissue damage during intravascular procedures in neonatal coarctation tissue. The aim of this study was to perform balloon angioplasty and stenting on coarctation the aorta samples harvested at the time of surgery from neonatal patients and visualise the deformation under ultrasound guidance. From this, the novel collagen hybridizing peptide (CHP) was used to assess the level of collage denaturation and microstructural damage this tissue experienced when undergoing these procedures. The results demonstrate that balloon angioplasty singularly is not a viable treatment option at maintaining the lumen diameter unless higher levels of stretch are achieved to permanently deform the tissue. Five out of six neonatal coarctation samples were successfully stented with no stent failure, proving that stent insertion is a viable option to achieve the desired lumen diameter. In addition, for both procedures, increased collagen damage was observed with higher tissue strain. Overall, this work would suggest stent placement as the best option to achieve reliable lumen gain and to limit the level of the level of collagen damage when stretching the tissue to achieve the required lumen diameter.