Calcified aortic stenosis is a common cardiovascular disease whose prevalence increases with age (10% in people over 70). To date, there is no drug treatment and the only option available to patients is surgical aortic valve replacement, which usually involves implantation of a bioprosthesis (BP). The Achilles heel of this valve substrate is the irreversible structural degeneration of the aortic valve bioprosthesis (SVD), which limits its durability.

The aim of this work is to develop a model that allows the SVD to be studied in a physiological context as close as possible to that of humans.

Orthotopic implantation of a BP was performed in the Yucatan minipig, a model with good phenotypic control and metabolic properties close to those of humans. Avalus 19 BP is implanted in 18-month-old male Yucatan minipigs. The surgery was refined pre-, intra- and postoperatively before the animals were enrolled in the SVD study protocol (3-month postoperative follow-up). Echocardiography was performed during the follow-up. Explantation of the bioprostheses in the victims and analysis by histology and electron microscopy.

Eleven Yucatan minipigs (average 65.4±8.8kg) were operated on: 5 for model validation and 6 as part of the SVD study protocol. The first animals were used to refine the anaesthesia, surgical methods and resuscitation of the pig. Animals were sacrificed after 2 days and up to 3 months after surgery. Three animals died prematurely during the 3-month follow-up protocol. The ETT and histological data confirmed the relevance of the model (Fig. 1).

These preliminary data confirm the feasibility and relevance of the mini-pig model for studying the pathophysiological mechanisms associated with SVD.