Biology subjects

Stergiopulos, N.

Publications and source records attributed to Stergiopulos, N..

2 recordsLinked to original sources

bioRxiv2023

In vivo evaluation of a novel compliance-matching vascular graft

BackgroundThe mismatch of elastic properties between the arterial tissue and the vascular grafts, commonly called compliance mismatch, is responsible for many deleterious post-operative complications. Currently, there is an absence of prostheses that conform with the compliance of healthy aortas. ObjectivesWe proposed a novel compliance-matching graft design, composed of a standard aortic graft surrounded by an optimized Nickel-Titanium compliance-augmenting layer. We aimed to evaluate the in vivo performance of the novel grafts in a swine model and compare it to the native aorta and to gold-standard aortic grafts. MethodsWe replaced the thoracic aorta of six domestic pigs with compliance-matching grafts under cardiopulmonary bypass. We removed the compliance-regulating layer of the compliant grafts, so that gold-standard grafts remained implanted. ResultsThe compliance-matching grafts were implanted without surgical complications and without inducing post-operative hypertension by maintaining systolic pressure (11% increase), aortic pulse wave velocity (17% decrease) and aortic distensibility (40% increase) at healthy levels. The gold-standard grafts caused a significant rise in systolic pressure (47%), pulse pressure (126%) and pulse wave velocity (64%). ConclusionsOur novel compliant grafts could diminish the complications caused by compliance-mismatch and they could surpass the clinical performance of existing prostheses. The proposed grafts comprise a step towards optimized treatment and improved life expectancy of patients subjected to aortic replacement.

bioengineering↗

bioRxiv2022

Wet Adhesive Hydrogels to Correct Malacic Trachea (Tracheomalacia): A Proof of Concept

Tracheomalacia (TM) is a condition in which the anterior part of the trachea consisting of cartilage and/or the posterior part consisting muscle are too soft to ensure its mechanical support. This situation may result in an excessive and potentially lethal collapse of the airway in the newborns. Current treatment techniques include tracheal reconstruction, tracheoplasty, endo- and extraluminal stents, but are all facing important limitations. To reduce the shortcomings of actual TM treatments, this work proposes a new strategy by wrapping an adhesive hydrogel patch extraluminally around a malacic trachea. To validate this approach, first a numerical model revealed that a hydrogel patch with sufficient mechanical and adhesion strength can potentially preserve the tracheas physiological shape. Accordingly, a new hydrogel formulation was synthesized employing the hydroxyethyl acrylamide (HEAam) and polyethylene glycol methacrylate (PEGDMA) as main polymer network and crosslinker, respectively. These hydrogels provide excellent adhesion on wet tracheal surfaces, thanks to a two-step photo-polymerization approach. Ex vivo experiments revealed that the developed adhesive hydrogel patches can restrain the collapsing of malacic trachea under applied negative pressure. This study, to be confirmed by in vivo studies, is open to the possibility of a new treatment in the difficult clinical situation of tracheomalacia in newborns.

bioengineering↗