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Background: We have developed a tissue engineered cardiac patch derived from a 3-dimensional (3D) myocardial tissue reinforced with extracellular matrix in an effort to enhance in situ myocardial regeneration. The feasibility of the patch was evaluated in a porcine model by various modalities to assess both the constructive and functional aspects of regeneration., Methods: A spheroid-based 3D multicellular tissue was created using a 3D net mold system that incorporated cardiomyocytes and embryonic fibroblast cells. The 3D multicellular tissue was incorporated with extracellular matrix sheets and surgically implanted into the right ventricle of a healthy porcine model (n = 4). After 60 days, the implanted patches were evaluated by cardiac magnetic resonance imaging and electroanatomic mapping studies as well as by post-euthanasia analyses, including measurements of mechanical viscoelasticity., Results: Cardiac magnetic resonance imaging revealed improved regional tissue perfusion in the patch area. Electroanatomic mapping exhibited regenerated electrical conductivity in the patch, as evidenced by relatively preserved voltage regions (1.11 ± 0.8 mV) in comparison to the normal right ventricle (4.7 ± 2.8 mV). Histologic and tissue analyses confirmed repopulation of site-specific host cells, including premature cardiomyocytes and active vasculogenesis. These findings were supported by quantitative reverse transcription-polymerase chain reaction., Conclusions: The tissue engineered cardiac patch effectively facilitated in situ constructive and functional myocardial regeneration, characterized by increased regional tissue perfusion and positive electrical activity in the porcine model., Competing Interests: DISCLOSURES The authors have no conflicts of interest to disclose.

Fibrosing mediastinitis (FM) is a rare, potentially progressive disease resulting from an idiosyncratic immune response to a variety of stimuli that lead to fibrous infiltration of the mediastinum and possible narrowing of the bronchovascular structures. We report an unusual case of FM in a pediatric patient presenting as myopericarditis and progressing to pericardial thickening and encasement of the mediastinal vascular structures needing surgical intervention. Imaging, including transthoracic echocardiography, cardiac computed tomography, and cardiac magnetic resonance played a crucial role in the diagnosis, assessment, and follow-up. Contrast-enhanced computed tomography can be especially helpful to demonstrate potential findings associated with FM., Competing Interests: The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2024 The Authors.)

Competing Interests: The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

Aortic thrombus formation in children is uncommon, particularly in an otherwise healthy pediatric patient. Thromboembolism of such thrombi resulting in subsequent ST-segment elevation myocardial infarction is, thus, exceedingly rare. ( Level of Difficulty: Intermediate. )., Competing Interests: The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Background: Patient-specific, 3-dimensional printed, tissue engineered vascular grafts (3DTEVGs) are manufactured to optimize hemodynamic performance and to accommodate growth. We evaluate growth outcomes of 3DTEVGs compared with standard grafts for pulmonary artery reconstruction in porcine models., Methods: Magnetic resonance imaging (MRI) with 4-dimensional flow data was acquired in porcine models (n = 8). 3DTEVGs guided in design by computational flow dynamics were implanted (n = 4), with polytetrafluorethylene grafts used as controls (n = 4). Postoperative MRI and histologic features of explanted grafts were evaluated after 10 weeks., Results: All pigs survived, with evidence of patent grafts on postoperative MRI. Graft inner diameter changes were 0.47 ± 2.31 mm in 3DTEVGs and -4.61 ± 2.15 mm in controls ( P  = .018). Mean main pulmonary artery wall shear stress was significantly lower in 3DTEVGs (7.12 ± 4.21 Pa) than in controls (18.15 ± 8.37 Pa; P  = .0396). Histologic evaluation of 3DTEVGs showed a single layer of endothelial cells, an organized smooth muscle layer, and collagen deposition with a remaining scaffold area of 21.37% ± 20.46%., Conclusions: Our patient-specific 3DTEVGs demonstrated optimal anatomic fit while maintaining ideal flow dynamics and promoting appropriate neovessel formation., (© 2023 The Authors.)

Objective: Many patients who require hemodialysis treatment will often require a prosthetic graft after multiple surgeries. However, the patency rate of grafts currently available commercially has not been satisfactory. Tissue engineering vascular grafts (TEVGs) are biodegradable scaffolds created to promote autologous cell proliferation and functional neotissue regeneration and, accordingly, have antithrombogenicity. Therefore, TEVGs can be an alternative prosthesis for small diameter grafts. However, owing to the limitations of the graft materials, most TEVGs are rigid and can easily kink when implanted in limited spaces, precluding future clinical application. Previously, we developed a novel corrugated nanofiber graft to prevent graft kinking. Reinforcement of these grafts to ensure their safety is required in a preclinical study. In the present study, three types of reinforcement were applied, and their effectiveness was examined using large animals., Methods: In the present study, three different reinforcements for the graft composed of corrugated poly-ε-caprolactone (PCL) blended with poly(L-lactide-co-ε-caprolactone) (PLCL) created with electrospinning were evaluated: 1) a polydioxanone suture, 2) a 2-0 polypropylene suture, 3) a polyethylene terephthalate/polyurethane (PET/PU) outer layer, and PCL/PLCL as the control. These different grafts were then implanted in a U-shape between the carotid artery and jugular vein in seven ovine models for a total of 14 grafts during a 3-month period. In evaluating the different reinforcements, the main factors considered were cell proliferation and a lack of graft dilation, which were evaluated using ultrasound examinations and histologic and mechanical analysis., Results: No kinking of the grafts occurred. Overall, re-endothelialization was observed in all the grafts at 3 months after surgery without graft rupture or calcification. The PCL/PLCL grafts and PCL/PLCL grafts with a polydioxanone suture showed high cell infiltration; however, they had become dilated 10 weeks after surgery. In contrast, the PCL/PLCL graft with the 2-0 suture and the PCL/PLCL graft covered with a PET/PU layer did not show any graft expansion. The PCL/PLCL graft covered with a PET/PU layer showed less cell infiltration than that of the PCL/PLCL graft., Conclusions: Reinforcement is required to create grafts that can withstand arterial pressure. Reinforcement with suture materials has the potential to maintain cell infiltration into the graft, which could improve the neotissue formation of the graft., (© 2022 by the Society for Vascular Surgery. Published by Elsevier Inc.)

Objective: Prosthetic grafts are often needed in open vascular procedures. However, the smaller diameter prosthetic grafts (<6 mm) have low patency and often result in complications from infection. Tissue-engineered vascular grafts (TEVGs) are a promising replacement for small diameter prosthetic grafts. TEVGs start as a biodegradable scaffold to promote autologous cell proliferation and functional neotissue regeneration. Owing to the limitations of graft materials; however, most TEVGs are rigid and easily kinked when implanted in limited spaces, which precludes clinical application. We have developed a novel corrugated nanofiber graft to prevent kinking., Methods: TEVGs with corrugated walls (5-mm internal diameter by 10 cm length) were created by electrospinning a blend of poly-ε-caprolactone and poly(L-lactide-co-caprolactone). The biodegradable grafts were then implanted between the carotid artery and the external jugular vein in a U-shape using an ovine model. TEVGs were implanted on both the left and right side of a sheep (n = 4, grafts = 8). The grafts were explanted 1 month after implantation and inspected with mechanical and histologic analyses. Graft patency was confirmed by measuring graft diameter and blood flow velocity using ultrasound, which was performed on day 4 and every following week after implantation., Results: All sheep survived postoperatively except for one sheep that died of acute heart failure 2 weeks after implantation. The graft patency rate was 87.5% (seven grafts out of eight) with one graft becoming occluded in the early phase after implantation. There was no significant kinking of the grafts. Overall, endothelial cells were observed in the grafts 1 month after the surgeries without graft rupture, calcification, or aneurysmal change., Conclusions: Our novel corrugated nanofiber vascular graft displayed neotissue formation without kinking in large animal model., (© 2020 by the Society for Vascular Surgery. Published by Elsevier Inc.)