Impact of Stent-Graft Oversizing on the Thoracic Aorta:<b>Experimental Study in a Porcine Model</b>

Sincos, Igor Rafael; Aun, Ricardo; Silva, Erasmo Simão da; Belczak, Sérgio Quilici; Higuchi, Maria de Lourdes; Gornati, Vitor Cervantes; Gigglio, Pedro Nogueira; Baptista, Anna Paula Weinhardt; Figueiredo, Luiz Francisco Poli de

doi:10.1583/11-3470.1

Cited by 24 publications

(29 citation statements)

References 13 publications

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“…1,7 However, data are limited on the interaction between the stent-graft and the aortic wall with regard to biomechanics and inflammatory and structural changes. [8][9][10][11][12][13] In this study, we analyzed histological alterations 5 days after TEVAR in a porcine model and found significant aortic wall thinning and luminal necrosis in every specimen covered by the stent.…”

Section: Discussionmentioning

confidence: 95%

“…Histological evaluation of the specimens covered by the stent showed stretching of the elastic and collagen fibers, which is a structural correlate of strain. A recent animal study conducted by Sincos et al 11 performed 2 biomechanical tests to evaluate the effect of different levels of stent-graft oversizing (up to 40%) on nonatherosclerotic aortas 4 weeks after implantation. Maximum supported strength, maximum tension, and stress of the aortic wall all were reduced proportional to the degree of oversizing in all groups.…”

Section: Discussionmentioning

confidence: 99%

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Early Histological Changes in the Porcine Aortic Media After Thoracic Stent-Graft Implantation

Scheumann

Heilmann²,

Beyersdorf³

et al. 2012

Journal of Endovascular Therapy

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¤ ¤Purpose: To describe the histological findings in the aortic wall 5 days after thoracic endovascular aortic repair (TEVAR) in a porcine model. Methods: Two overlapping stent-grafts were implanted in each of 6 juvenile pigs, covering the entire descending thoracic aorta (DTA). On the 5 th postoperative day, tissue samples were taken from the DTA in each animal. Medial thickness and medial necrosis were quantified and compared to measurements from the aortas of 6 control animals. Results: Significant medial thinning was observed in stent-covered regions in the test animals. At the proximal landing zone, aortic wall thickness changed from 1387668 to 782674 mm within the covered aortic segment (p50.028); at the distal landing site, the wall thickness was 365667 mm within the stent and 501657 mm distally (p50.028). In the overlap zone, the aortic wall measured 5246122 vs. 1053677 mm in native controls (p50.004). Aortic thickness proximal to the graft did not differ from the proximal region of native aortas (1468696 vs. 1513680 mm, p50.423), but the aorta was significantly thinner distal to the stent (707638 vs. 815652 mm, p50.004). Laminar necrosis constituted 38%67% of the media in the proximal landing zone, 54%64% in the overlap zone, and 46%613% in the distal landing zone. Conclusion: In this porcine model, significant medial thinning and necrosis of the stented aorta was observed. The findings suggest an early phase of vulnerability of the aortic wall, before scarring and adaptive changes have strengthened the residual aorta.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Early Histological Changes in the Porcine Aortic Media After Thoracic Stent-Graft Implantation

Scheumann

Heilmann²,

Beyersdorf³

et al. 2012

Journal of Endovascular Therapy

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“…One adaptation is a considerable loss of elasticity, especially at the area of compression, regardless of the percentage of oversizing [62]. The same study showed that the max strength sustained and the stress supported by fragments of the aortic wall suffered a linear and progressive loss with increased oversizing [62]. This change can be contributed to a reorganization and change in quantity of collagen and elastic fibers distributed around the apposition sites.…”

Section: Histology Of the Attachment Sites And Oversizingmentioning

confidence: 89%

“…When a stent graft is implanted, a foreign body reaction can result. One adaptation is a considerable loss of elasticity, especially at the area of compression, regardless of the percentage of oversizing [62]. The same study showed that the max strength sustained and the stress supported by fragments of the aortic wall suffered a linear and progressive loss with increased oversizing [62].…”

Section: Histology Of the Attachment Sites And Oversizingmentioning

confidence: 90%

“…This change can be contributed to a reorganization and change in quantity of collagen and elastic fibers distributed around the apposition sites. In particular, collagen increases in the aortic wall irrespective of the degree of oversizing [62] On the other hand, the amount of muscle fibers decrease in the inner third of the wall with more oversizing [62]. Importantly, oversizing >40% showed evidence of disruption of the fiber content and formation of an aneurysm within the aortic wall [63].…”

Section: Histology Of the Attachment Sites And Oversizingmentioning

confidence: 99%

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Endograft Sizing for Abdominal Aortic Aneurysms

Sher¹,

Tadros²

2017

Aortic Aneurysm

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While a tight seal and fixation of aortic stent-grafts to the vessel wall are vital for positive outcomes in treating abdominal aortic aneurysms (AAAs), optimal aortic stent-graft sizing for endovascular aneurysm repair (EVAR) remains debatable. We performed a holistic review of the data surrounding the sizing of endografts using instructions for use (IFU) guidelines, as well as experimental, computational, and clinical studies. Most clinical studies that have investigated the role of sizing and outcomes are limited by the strict selection criteria, or the inability to account for the multitude of confounders associated with sizing. Currently, oversizing of endografts between 10 and 20% remains safe and favored, but sizing outside the IFU guidelines frequently occurs. Oversizing up to 25% appears to be associated with decreased rates of proximal endoleak and aneurysm sac enlargement, while excessive oversizing (>30%) has been linked to graft infolding, collapse, and aortic dilatation. It is unclear, however, whether there is an association between oversizing associated with neck dilatation and graft migration. During sizing, surgeons should take an individual approach and consider several factors including device type, calcification and/or thrombus of apposition site, hemodynamics, and aortoiliac morphology.

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Percutaneous endovascular delivery of calcium chloride to the intact porcine carotid artery: A novel animal model of arterial calcification

Abrão

Campos

Cavalcante

et al. 2020

Cathet Cardio Intervent

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Objective: The present study evaluated the effect of endovascular administration of calcium chloride to the carotid artery of swines, to create a model of arterial calcification. Methods: Fifteen Large White pigs were used for the study. Via endovascular treatment, carotid arteries were exposed during 9 min to either calcium chloride (experimental artery) or saline (control artery) with the use of the TAPAS catheter. Intravascular ultrasound (IVUS) imaging was obtained at baseline, postprocedure and at 30 days. Optical coherence tomography (OCT) imaging was obtained in vitro after carotids were harvested. Longitudinally cut parallel arterial segments were placed in a system of delicate clamps and underwent uniaxial strain test. All arteries underwent histopathological examination. Results: Calcium chloride treated segments showed extensive circumferential parietal calcification evident on both IVUS and OCT. Reduction in minimal lumen area on IVUS was evident in experimental arteries both at 24 hr and 30 days postprocedure. Histopathologic assessment (Von Kossa stain) confirmed medial calcification with mild intimal thickening. Biomechanical testing showed treated segments to have smaller breaking strength and less elastic deformation than controls. Conclusion: We developed a nonexpensive, reproducible model of early carotid medial calcification in pigs. Our model has the potential to help the development of research to unravel mechanisms underlying arterial calcification, the use of current or new devices to treat calcified lesions as well as to serve as an option for training interventionalists on the use of such devices.

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Impact of Stent-Graft Oversizing on the Thoracic Aorta:Experimental Study in a Porcine Model

Cited by 24 publications

References 13 publications

Early Histological Changes in the Porcine Aortic Media After Thoracic Stent-Graft Implantation

Early Histological Changes in the Porcine Aortic Media After Thoracic Stent-Graft Implantation

Endograft Sizing for Abdominal Aortic Aneurysms

Percutaneous endovascular delivery of calcium chloride to the intact porcine carotid artery: A novel animal model of arterial calcification

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