In vivo endothelialization and neointimal hyperplasia assessment after angioplasty of sheep carotid artery with a novel polycarbonate polyurethane patch

Abstract

The aim of this study was to compare two variants of a novel polycarbonate polyurethane prosthesis with polyethylene terephthalate (Dacron) prosthesis in an established sheep model of carotid patch angioplasty. Two variants of the polycarbonate polyurethane prosthesis were used: (1) Polycarbonate polyurethane equal (PCU-e) prosthesis consisted of a multilayered porous structure with equal internal and external layers; (2) Polycarbonate polyurethane with more porous inner layers (PCU-mp) prosthesis had more porous inner layers than external layers. Carotid patch angioplasty was performed in 12 sheep: in six sheep, the PCU-e variant and in the other six sheep, the PCU-mp variant was implanted. Dacron patches were implanted in the contralateral carotid artery of all sheep as a control. Half of the animals with each polycarbonate polyurethane variant were euthanized after two weeks and the other half after eight weeks. Cellular infiltration, endothelialization, and neointimal hyperplasia were examined. All grafts were patent, and no thrombus was seen in any of the harvested arteries. The pores of all the three patch materials allowed infiltration of inflammatory cells, capillaries, and connective tissue. After eight weeks, a nearly complete endothelialization was visible in all patch groups without an obvious difference between the three patch materials. The neointima was thinner in the PCU patches (PCU-e: 56 ± 13 µm, PCU-mp: 119 ± 60 µm) when compared to Dacron patches (156 ± 64 µm) after two weeks. After 8 weeks, a further neointimal growth was detectable, without any significant difference of neointimal thickness between the three patch materials (Dacron: 274 ± 82 µm, PCU-e: 324 ± 98 µm, PCU-mp: 235 ± 59 µm). With the novel polycarbonate polyurethane patch materials, we achieved promising functional and morphological results with 100% patency and nearly complete endothelialization. Our findings showed at least a non-inferiority of the novel polycarbonate polyurethane patch material compared to Dacron. There were no significant differences detected between the two polycarbonate polyurethane patch variants.

The novel hybrid polycarbonate polyurethane / polyester three-layered large-diameter artificial blood vessel

“…Responses to the artificial blood vessels, and the quality and velocity of endothelialization could be different between human and sheep. 16 In our study, the length of implanted artificial blood vessels is about 2 cm, which cannot well reflect the clinical application scenarios. Besides, since this experiment is the first step of this preclinical animal experiment, it is mainly to verify the hemocompatibility, histocompatibility, effectiveness, and safety of this artificial blood vessel, so there are no control groups.…”

“…Dacron) and polytetrafluoroethylene (PTFE). 16 However, the results of long-term follow up about Dacron V R grafts had demonstrated that the mismatch of biomechanical properties could cause multiple complications. 17 Hence, polyurethane (PU) artificial blood vessels were designed to reduce this mismatch between artificial blood vessels and innate arteries.…”

“…16,21,22 Inflammatory and mesenchymal cells entering the artificial blood vessel wall and endothelia covering the endo-surface of artificial blood vessels are the optimal patterns of graft healing. 16,23 Totally, endothelialization of the artificial blood vessels' inner surface has three ways: trans-anastomotic ingrowth of the innate arteries' endothelia, transmural ingrowth of the Implantation sites' capillaries, and hematogenous seeding of endothelia from the circulatory system. 16,24 To prevent thrombosis and intimal hyperplasia, it is crucial to endothelialize the artificial blood vessels' inner surface.…”

“…16,23 Totally, endothelialization of the artificial blood vessels' inner surface has three ways: trans-anastomotic ingrowth of the innate arteries' endothelia, transmural ingrowth of the Implantation sites' capillaries, and hematogenous seeding of endothelia from the circulatory system. 16,24 To prevent thrombosis and intimal hyperplasia, it is crucial to endothelialize the artificial blood vessels' inner surface. 16 The endothelia make a great difference in the coagulation process and thrombosis.…”

In vivo endothelialization and neointimal hyperplasia assessment after rabbit carotid endarterectomy with bovine pericardium

“…Yet, these studies did not clarify the difference between PC and DC after CEA. In addition, re-endothelialization on the patch has always been particularly concerning, as it is directly related to thrombosis (20). Moreover, it is also unclear whether the neointima on the patch is functional.…”