A Biomechanical Double Sac (Pericardium‐Pebax) for Specially Shaped Artificial Ventricles: A Computerized Study to Evaluate Its Mechanical and Volumetric Properties

Abstract

For original ovoid shaped artificial ventricles. a biomechanical double sac consisting of a biological sac (porcine pericardium) as the blood contact interface and a synthetic sac (Pebax 3533) as the mechanical support to assume systolic-diastolic dynamic constraints was conceived. The volumetric and mechanical properties were assessed with a three-dimensional modeling of Pebax sacs and computerized simulations of their systolic distortions for both right and left ventricular configurations. The stresses and strains of these sacs were represented as quantitative mappings for a maximum end-systolic state and were below the respective threshold values above which the Pebax material is jeopardized for permanent structure impairment. After fatigue tests applied on Pebax strips under the alleged working conditions of Pebax sacs, the material structure was unchanged and maintained its intrinsic mechanical properties. The theoretical maximum stroke volumes were 74.4 cm3 and 62.4 cm' for the left and right ventricular configurations, respectively. With these mechanical and volumetric features, the biomechanical double sac concept was considered valid and could be provided for a consequent specific total artificial heart. The acknowledged needs for artificial hearts (left ventricular assist devices and total artificial hearts [TAHs]) are induced by the increases in the numbers of patients suffering from end-stage congestive heart failure refractory to medical treatment and by the lack of cardiac grafts for heart transplantations (1-3). However, their common use to satisfy such clinical needs has not yet been possible because of persistent problems despite recent progress. For example, thromboembolic events, infectious complications, anatomical mismatches, and mechanical failures have often been reported for current models and ascribed to their design and/or their biomaterials (4-8) so that it appeared to be appropriate to explore and perfect new designs and biomaterials to resolve these problems (9,lO). For this purpose, a new design of artificial ventricles unique in their truncated ovoid shapes and biomechanical double

Thermoplastic Polyamide Elastomers: Synthesis, Structures/Properties, and Applications

“…[ 57 ] Besides, Pebax also can be extensively used in producing medical tubing or polymeric stent for demanding medical procedures, which require high kink resistance and relatively high tensile strength as well as outstanding flexibility and good tear resistance. [ 100 ] Moreover, there are other more broad employments of Pebax in diverse industrial fields, e.g., the automotive, transportation, or telecommunication industries because of its great mechanical properties, easy processibility, and nice surface appearance. [ 101 ] Furthermore, on account of its tunable and extensive range of mechanical performances, Pebax also can be applied as the toughening agent for harder polymer materials or used as the strengthening agent for softer polymer materials.…”