(I-327) Optimizing Implantable Sleeve Design for Improved Left Ventricular Function Post-Myocardial Infarction: A Computational Approach

Introduction:: Introduction: Myocardial infarction (MI) significantly contributes to adverse remodeling of the left ventricle (LV), resulting in impaired cardiac function. Implantable epicardial sleeves have emerged as a potential solution to mitigate this process [1]. Advancements in implantable epicardial sleeve design, material properties, and the introduction of novel parameters, such as geometry and architectural behavior, have shown promising results in improving cardiac function. One of the architectural behaviors explored in this study is the auxetic design, which has demonstrated unique mechanical properties. This study aims to develop a computational biventricular (BV) model based on myocardial infarcted murine hearts and a simplified spheroidal model to optimize epicardial sleeve design for improved LV function post-MI.


Materials and Methods:: Materials and methods: BV and spheroidal models integrated hyperelastic, transversely isotropic material properties and active force parameters obtained via an inverse model while employing the Frank-Starling relationship within the simulation framework [2]. The research focused on evaluating various epicardial sleeve parameters under two distinct categories: (i) geometry, involving the thickness field of the sleeve covering the epicardial surface and encompassing designs that cover different regions of the BV area (as shown in Figure 1b-e), and (ii) architecture, exploring the influence of patterns, such as auxetic surfaces (Figure 2c), on the sleeve's performance. The effects of these parameters were assessed by comparing pressure-volume (PV) loops and related parameters to a baseline model (infarct without a sleeve), which was validated against experimental data.

Results, Conclusions, and Discussions:: Results and Discussion: The preliminary results demonstrated the effectiveness of epicardial sleeves in reducing end-diastolic volume (EDV), preventing dilation, increasing stroke volume, and inhibiting stretching. Myocardial infarction (MI) significantly impacts the pressure-volume (PV) loop, as shown in Figure 3, with infarcted hearts experiencing increased EDV, end-systolic volume (ESV), and impaired cardiac function compared to healthy hearts. However, the implementation of epicardial sleeves led to a ~10% increase in ejection fraction (EF) in the BV heart, as well as improvements in LV function, such as reduced EDV, reduced ESV, and enhanced overall cardiac efficiency. Moreover, the sleeves limited further dilation and adverse remodeling. In particular, auxetic sleeves showed potential for even more significant improvements in EF and overall cardiac performance. By employing spheroidal models for auxetic designs, we achieved better control over the vast array of architectural patterns, enabling more effective optimization. Optimal outcomes were observed when the epicardial sleeve specifically covered the infarct area in an acute MI model sample. This highlights the importance of developing customized sleeve designs tailored to the unique characteristics of individual infarcted heart models, ensuring the best possible patient outcomes.


Conclusion: This study demonstrates the potential of personalized epicardial sleeve designs in improving LV function following myocardial infarction. The comprehensive approach, considering geometry, shape, architecture, and material properties, emphasizes the need for customizing the epicardial sleeve design to each patient's needs. Customized implants can enhance cardiac function and reduce adverse remodeling, ultimately improving patient outcomes. Future research should focus on integrating innovative design concepts and materials to develop patient-specific epicardial sleeve implants and evaluate their long-term effectiveness and safety in clinical settings.




Acknowledgements (Optional): : Acknowledgments: RA was supported by the NIH, under grant No. RR 00HL138288 (RA).


References (Optional): : [1] Roche, E. T., et al. "Soft robotic sleeve supports heart function." Sci. Transl. Med. 9.373 (2017): eaaf3925.

[2] Hunter, P. J., et al. "Modelling the mechanical properties of cardiac muscle." Prog. Biophys. 69.2-3 (1998): 289-331.