Multiscale, patient-specific computational fluid dynamics models predict formation of neointimal hyperplasia in saphenous vein grafts

Donadoni, Francesca; Pichardo‐Almarza, César; Homer‐Vanniasinkam, Shervanthi; Dardik, Alan; Díaz‐Zuccarini, Vanessa

doi:10.1016/j.jvscit.2019.09.009

Cited by 11 publications

(14 citation statements)

References 28 publications

(34 reference statements)

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“…As mentioned above, external factors unrelated to the physical properties of Biotubes were considered because the stenosis of Biotubes occurred locally and was delayed. Simulations of saphenous vein graft stenosis after lower extremity bypass surgery using computational fluid dynamics [ 20 , 21 , 22 ] and a discussion of the angle and shape of the anastomosis [ 23 ] have been reported, and the phenomenon of IH in the vascular graft was discussed from a fluid dynamics perspective. Flow geometrical changes, stagnation, and turbulence are risks in the local graft area because bypass surgery is essentially an artificial blood flow design that differs from the line of a native artery.…”

Section: Discussionmentioning

confidence: 99%

Carotid Artery Bypass Surgery of In-Body Tissue Architecture-Induced Small-Diameter Biotube in a Goat Model: A Pilot Study

Umeno,

Mori,

Iwai

et al. 2024

Bioengineering

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Biotubes are autologous tubular tissues developed within a patient’s body through in-body tissue architecture, and they demonstrate high potential for early clinical application as a vascular replacement. In this pilot study, we used large animals to perform implantation experiments in preparation for preclinical testing of Biotube. The biological response after Biotube implantation was histologically evaluated. The designed Biotubes (length: 50 cm, internal diameter: 4 mm, and wall thickness: 0.85 mm) were obtained by embedding molds on the backs of six goats for a predetermined period (1–5 months). The same goats underwent bypass surgery on the carotid arteries using Biotubes (average length: 12 cm). After implantation, echocardiography was used to periodically monitor patency and blood flow velocity. The maximum observation period was 6 months, and tissue analysis was conducted after graft removal, including the anastomosis. All molds generated Biotubes that exceeded the tensile strength of normal goat carotid arteries, and eight randomly selected Biotubes were implanted. Thrombotic occlusion occurred immediately postoperatively (1 tube) if anticoagulation was insufficient, and two tubes, with insufficient Biotube strength (<5 N), were ruptured within a week. Five tubes maintained patency for >2 months without aneurysm formation. The spots far from the anastomosis became stenosed within 3 months (3 tubes) when Biotubes had a wide intensity distribution, but the shape of the remaining two tubes remained unchanged for 6 months. The entire length of the bypass region was walled with an αSMA-positive cell layer, and an endothelial cell layer covered most of the lumen at 2 months. Complete endothelial laying of the luminal surface was obtained at 3 months after implantation, and a vascular wall structure similar to that of native blood vessels was formed, which was maintained even at 6 months. The stenosis was indicated to be caused by fibrin adhesion on the luminal surface, migration of repair macrophages, and granulation formation due to the overproliferation of αSMA-positive fibroblasts. We revealed the importance of Biotubes that are homogeneous, demonstrate a tensile strength > 5 N, and are implanted under appropriate antithrombotic conditions to achieve long-term patency of Biotube. Further, we clarified the Biotube regeneration process and the mechanism of stenosis. Finally, we obtained the necessary conditions for a confirmatory implant study planned shortly.

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Section: Discussionmentioning

confidence: 99%

Carotid Artery Bypass Surgery of In-Body Tissue Architecture-Induced Small-Diameter Biotube in a Goat Model: A Pilot Study

Umeno,

Mori,

Iwai

et al. 2024

Bioengineering

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“…184,185 Computational simulations in models with deformable walls suggest that neointimal growth is linked to regions with both low WSS and a high OSI, where such regions do not localize to any particular graft position and exhibit significant heterogeneity in the degree of stenosis. 186,187 However, simulations with larger patient cohorts using these methods are necessary to establish clear thresholds, as the degree of patient-to-patient variability limits the extrapolation of these results to inform clinical decisions.…”

Section: Vascular Graft Performance In the Surgical Settingmentioning

confidence: 99%

Hemodynamics and Wall Mechanics of Vascular Graft Failure

Szafron,

Heng,

Boyd

et al. 2024

ATVB

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Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix. In this review, we outline experimental and computational tools used to quantify metrics of biomechanical loading in vascular grafts and highlight those that show potential in predicting graft failure for diverse disease contexts. We include metrics derived from both fluid and solid mechanics that drive feedback loops between mechanobiological processes and changes in the biomechanical state that govern the natural history of vascular grafts. As illustrative examples, we consider application-specific coronary artery bypass grafts, peripheral vascular grafts, and tissue-engineered vascular grafts for congenital heart surgery as each of these involves unique circulatory environments, loading magnitudes, and graft materials.

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“…Abnormal blood flow in the graft has long been known as a key impairment factor that alters graft healing and overall patency ( Schwarz et al, 2021 ). Computational flow dynamics tools, with the inputs of graft location, diameter, length and/or compliance together with graft design, have been applied to predict not only flow conditions but also consequent remodeling of a graft ( Lu et al, 2014 ; Ramachandra et al, 2017 ; Donadoni et al, 2020 ). Variations in these physical characteristics of a graft delicately influence local fluid stresses in a blood vessel or a graft.…”

Section: Factors Impairing Healing or Regeneration Around Vascular Gr...mentioning

confidence: 99%

Strategies to counteract adverse remodeling of vascular graft: A 3D view of current graft innovations

Tan

Boodagh

Parthiban

et al. 2023

Front. Bioeng. Biotechnol.

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Vascular grafts are widely used for vascular surgeries, to bypass a diseased artery or function as a vascular access for hemodialysis. Bioengineered or tissue-engineered vascular grafts have long been envisioned to take the place of bioinert synthetic grafts and even vein grafts under certain clinical circumstances. However, host responses to a graft device induce adverse remodeling, to varied degrees depending on the graft property and host’s developmental and health conditions. This in turn leads to invention or failure. Herein, we have mapped out the relationship between the design constraints and outcomes for vascular grafts, by analyzing impairment factors involved in the adverse graft remodeling. Strategies to tackle these impairment factors and counteract adverse healing are then summarized by outlining the research landscape of graft innovations in three dimensions—cell technology, scaffold technology and graft translation. Such a comprehensive view of cell and scaffold technological innovations in the translational context may benefit the future advancements in vascular grafts. From this perspective, we conclude the review with recommendations for future design endeavors.

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Multiscale, patient-specific computational fluid dynamics models predict formation of neointimal hyperplasia in saphenous vein grafts

Cited by 11 publications

References 28 publications

Carotid Artery Bypass Surgery of In-Body Tissue Architecture-Induced Small-Diameter Biotube in a Goat Model: A Pilot Study

Carotid Artery Bypass Surgery of In-Body Tissue Architecture-Induced Small-Diameter Biotube in a Goat Model: A Pilot Study

Hemodynamics and Wall Mechanics of Vascular Graft Failure

Strategies to counteract adverse remodeling of vascular graft: A 3D view of current graft innovations

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