Towards the solution for infantile aortic coarctation

Aortic coarctation is an abnormal narrowing of the aorta, the main artery of our body: a type of chronic lesion that occurs in newborns and that, if not treated, can lead to other health problems in the patient, in the short or long term. long-term, such as kidney or heart failure. The treatment of this disease can be carried out from two approaches: open-heart surgery, or the implantation of an endovascular stent, requiring frequent surgical reinterventions.

This aortic lesion occurs occasionally in newborns, due to an immaturity of the germ cells that remain in fetal size, leaving a narrowed and hardened artery. As it is a pediatric disease, children’s arteries are very small, as are the stents, so that when the child grows, and his aorta too, the implanted stents remain small. Not being able to keep up with the growth of the child, various reoperations and frequent opening of the stent are required.

In this context, the Polycoarct project arose, which aims to design and develop new polymeric stents adapted to the arterial growth needs of children affected by aortic coarctation, thus reducing or avoiding new surgical interventions.

The project is carried out by a research group led by Dr. Jordi Martorell from the Vascular Engineering and Applied Biomedicine Group (GEVAB) of the Chemical Institute of Sarrià (IQS); with the participation of Dr. Mercedes Balcells (researcher at the Harvard-MIT Center for Biomedical Engineering in the United States, and GEVAB) and Dr. Jose J. Molins, from the same GEVAB group; Dr. Andrés García, from the IQS Industrial Products Engineering Group (GEPI); and the researcher Marta Pegueroles, from the Biomaterials, Biomechanics and Tissue Engineering (BBT) research group –experts in the development of biomaterials for cardiovascular applications– and professor at the East Barcelona School of Engineering (EEBE) of the Polytechnic University of Catalonia – Barcelona Tech (UPC).

This is an ambitious project that can only be approached from a multidisciplinary perspective, with contributions from engineering, chemistry, materials science, vascular biology, and medicine. For this reason, the three-way collaboration between the IQS, the MIT and the UPC is essential for success. In addition, the project has the external support of the Sant Joan de Déu Hospital in Esplugues de Llobregat (Barcelona) and the Boston Pediatric Hospital in the United States.

A stent. (Image: UPC)

Based on their experience, the IQS researchers will create a CAD-CAM platform to replicate different types of coarctation and design and print by additive manufacturing (3D) stents with an auxetic design that fit their geometry. An auxetic material is one that presents a negative Poisson’s ratio, which implies that, when producing traction in one direction, the perpendicular section of the material increases.

On behalf of the UPC, an alternative to auxetic stents will be developed, specifically, degradable polymeric stents with shape memory, using 3D printing techniques. Shape memory polymers are capable of changing their physical shape in response to an external stimulus, such as body temperature, due to a structural change. Coatings that promote re-endothelialization will also be developed –accelerating the coating of the stent surface with endothelial cells, key to avoiding thrombosis–, facilitating its integration into the artery, to later degrade.

Likewise, it will be verified that the new stents are biocompatible and the in vivo biological response of the most promising stents will be carried out in an animal model of aortic coarctation. (Source: UPC)