The Ross procedure is the only aortic valve replacement technique that can restore long-term survival while preserving quality-of-life. In the Ross procedure, the patient’s own pulmonary valve is placed in aortic position, forming a pulmonary autograft. The long-term durability of the Ross procedure remains limited by postoperative autograft dilatation under systemic blood pressures [1]. Although existing textile reinforcements can limit dilatation, they remain excessively stiff and fail to match the biomechanical behavior of native arterial tissue. By restricting physiological wall motion, current support strategies cause stress-shielding effects and vascular atrophy in the long-term. In this study, we develop and evaluate a mechanocompatible external support designed to stabilize autograft diameter while preserving arterial compliance [2]. Analytical analysis of arterial pressurization followed a classical continuum mechanics approach by establishing loading conditions and material properties, defining kinematics, and solving the balance equations to obtain the system stresses. Mechanocompatibility of the support was achieved by maximizing the distensibility coefficient: DC_V= (V_sys-V_dias)/(V_dias(p_sys-p_dias)) [3]. By incorporating diastolic and systolic in volume and pressure, this pulsatile metric enabled the in silico development of mechanocompatible scaffold properties. As a preclinical proof-of-concept, supported and unsupported pulmonary tissues were transplanted into rats’ abdominal aortas to mimic the mechanobiological conditions of the Ross procedure (Fig. 1). Diameters from postoperative µCT imaging and force-displacement data from ring-extension mechanical tests were used for model calibration (Table 1). Upon material optimization, the model predicts native aortic distensibility of the supported autografts, while maintaining vessel diameter. As such, our results define polymer characteristics that can prevent dilatation without compromising arterial biomechanics. This offers a translational pathway for future material development of medical textiles in cardiac surgery, with the potential to improve the long-term outcomes after the Ross procedure. References [1] Van Hoof et al. (2022). Front Cardiovasc Med. doi:10.3389/fcvm.2022.829120. [2] Vervenne et al. (2023). J Mech Behav Biomed Mater. doi:10.1016/j.jmbbm.2023.106170. [3] Vander Linden et al. (2023). JTCVS Open. doi:10.1016/j.xjon.2023.09.008.