Endovascular thrombectomy and repair of suprarenal inferior vena cava thrombosis: A case series.

OBJECTIVES: The objective of this study is to document the combined use of catheter-based thrombectomy/thrombolysis with endovascular repair of high-risk segments of the inferior vena cava in the setting of iatrogenic and traumatic injuries. While the use of endovascular techniques to treat caval thrombosis is well documented and often preferred due to its minimally invasive nature, there is still little literature that focuses on the nuances related to injury of high mortality areas of the IVC as a result of major trauma, transplant, and other surgical interventions. METHODS: An IRB-approved retrospective review of all patients undergoing IVC thrombectomy was performed at a single tertiary care academic center between January 2018 and July 2021. Cases were subsequently selected based on those who underwent primary mechanical thrombectomy followed by endovascular stenting (or angioplasty). Among this cohort, four patients who underwent this procedure in the context of iatrogenic and traumatic injuries were included. RESULTS: All four patients undergoing primary mechanical thrombectomy followed by endovascular stenting (or angioplasty) due to IVC thrombus and/or stenosis were technically successful with immediate positive clinical outcomes. CONCLUSIONS: Mechanical thrombectomy in conjunction with IVC recanalization via stenting may be a useful intervention with promising technical success and positive clinical outcomes for occlusive thrombosis and IVC stenosis.

Two-stage degradation and novel functional endothelium characteristics of a 3-D printed bioresorbable scaffold.

Bioresorbable scaffolds have emerged as a new generation of vascular implants for the treatment of atherosclerosis, and designed to provide a temporary scaffold that is subsequently absorbed by blood vessels over time. Presently, there is insufficient data on the biological and mechanical responses of blood vessels accompanied by bioresorbable scaffolds (BRS) degradation. Therefore, it is necessary to investigate the inflexion point of degradation, the response of blood vessels, and the pathophysiological process of vascular, as results of such studies will be of great value for the design of next generation of BRS. In this study, abdominal aortas of SD rats were received 3-D printed poly-l-actide vascular scaffolds (PLS) for various durations up to 12 months. The response of PLS implanted aorta went through two distinct processes: (1) the neointima with desirable barrier function was obtained in 1 month, accompanied with slow degradation, inflammation, and intimal hyperplasia; (2) significant degradation occurred from 6 months, accompanied with decreasing inflammation and intimal hyperplasia, while the extracellular matrix recovered to normal vessels which indicate the positive remodeling. These in vivo results indicate that 6 months is a key turning point. This "two-stage degradation and vascular characteristics" is proposed to elucidate the long-term effects of PLS on vascular repair and demonstrated the potential of PLS in promoting endothelium function and positive remodeling, which highlights the benefits of PLS and shed some light in the future researches, such as drug combination coatings design.

Effects of different positions of intravascular stent implantation in stenosed vessels on in-stent restenosis: An experimental and numerical simulation study.

Percutaneous coronary intervention (PCI) has been widely used in the treatment of atherosclerosis, while in-stent restenosis (ISR) has not been completely resolved. Studies have shown that changes in intravascular mechanical environment are related to ISR. Hence, an in-depth understanding of the effects of stent intervention on vascular mechanics is important for clinically optimizing stent implantation and relieving ISR. Nine rabbits with stenotic carotid artery were collected by balloon injury. Intravascular stents were implanted into different longitudinal positions (proximal, middle and distal relative to the stenotic area) of the stenotic vessels for numerical simulations. Optical coherence tomography (OCT) scanning was performed to reconstruct the three-dimensional configuration of the stented carotid artery and blood flow velocity waveforms were collected by Doppler ultrasound. The numerical simulations were performed through direct solution of Naiver-Stokes equation in ANSYS. Results showed that the distributions of time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and relative residual time (RRT) in near-end segment were distinctively different from other regions of the stent which considered to promote restenosis for all three models. Spearman rank-correlation analysis showed a significant correlation between hemodynamic descriptors and the stent longitudinal positions (rTAWSS = -0.718, rOSI = 0.898, rRRT = 0.818, p < 0.01). Histology results of the near-end segment showed neointima thickening deepened with the longitudinal positions of stent which was consistent with the numerical simulations. The results suggest that stent implantation can promote restenosis at the near-end segment. As the stenting position moves to distal end, the impact on ISR is more significant.

[Endothelial injury and its repair strategies after intravascular stents implantation].

Coronary atherosclerotic heart disease is a serious threat to human life and health. In recent years, the main treatment for it is to implant the intravascular stent into the lesion to support blood vessels and reconstruct blood supply. However, a large number of experimental results showed that mechanical injury and anti-proliferative drugs caused great damage after stent implantation, and increased in-stent restenosis and late thrombosis risk. Thus, maintaining the integrity and normal function of the endothelium can significantly reduce the rate of thrombosis and restenosis. Stem cell mobilization, homing, differentiation and proliferation are the main mechanisms of endothelial repair after vascular stent implantation. Vascular factor and mechanical microenvironmental changes in implanted sites have a certain effect on re-endothelialization. In this paper, the process of injury caused by stent implantation, the repair mechanism after injury and its influencing factors are expounded in detail. And repairing strategies are analyzed and summarized. This review provides a reference for overcoming the in-stent restenosis, endothelialization delay and late thrombosis during the interventional treatment, as well as for designing drug-eluting and biodegradation stents.

Endothelial injury and its repair strategies after intravascular stents implantation / 生物医学工程学杂志

Coronary atherosclerotic heart disease is a serious threat to human life and health. In recent years, the main treatment for it is to implant the intravascular stent into the lesion to support blood vessels and reconstruct blood supply. However, a large number of experimental results showed that mechanical injury and anti-proliferative drugs caused great damage after stent implantation, and increased in-stent restenosis and late thrombosis risk. Thus, maintaining the integrity and normal function of the endothelium can significantly reduce the rate of thrombosis and restenosis. Stem cell mobilization, homing, differentiation and proliferation are the main mechanisms of endothelial repair after vascular stent implantation. Vascular factor and mechanical microenvironmental changes in implanted sites have a certain effect on re-endothelialization. In this paper, the process of injury caused by stent implantation, the repair mechanism after injury and its influencing factors are expounded in detail. And repairing strategies are analyzed and summarized. This review provides a reference for overcoming the in-stent restenosis, endothelialization delay and late thrombosis during the interventional treatment, as well as for designing drug-eluting and biodegradation stents.

Atomic layer deposition enhanced grafting of phosphorylcholine on stainless steel for intravascular stents.

In-stent restenosis (ISR) and re-endothelialization delay are two major issues of intravascular stent in terms of clinical safety and effects. Construction of mimetic cell membrane surface on stents using phosphorylcholine have been regarded as one of the most powerful strategies to resolve these two issues and improve the performance of stents. In this study, atomic layer deposition (ALD) technology, which is widely used in semiconductor industry, was utilized to fabricate ultra-thin layer (10nm) of alumina (Al2O3) on 316L stainless steel (SS), then the alumina covered surface was modified with 3-aminopropyltriethoxysilane (APS) and 2-methacryloyloxyethyl phosphorylcholine (MPC) sequentially in order to produce phosphorylcholine mimetic cell membrane surface. The pristine and modified surfaces were characterized using X-ray photoelectron spectroscopy, atomic force microscope and water contact angle measurement. Furthermore, the abilities of protein adsorption, platelet adhesion and cell proliferation on the surfaces were investigated. It was found that alumina layer can significantly enhance the surface grafting of APS and MPC on SS; and in turn efficiently inhibit protein adsorption and platelet adhesion, and promote the attachment and proliferation of human umbilical vein endothelial cells (HUVEC) on the surfaces. In association with the fact that the deposition of alumina layer is also beneficial to the improvement of adhesion and integrity of drug-carrying polymer coating on drug eluting stents, we expect that ALD technology can largely assist in the modifications on inert metallic surfaces and benefit implantable medical devices, especially intravascular stents.

Evaluation of hemocompatibility of a new biopolymer material for bioabsorbable stents used for children with vascular stenosis in vitro / 临床儿科杂志

Objective To evaluate the hemocompatibility of polydioxanone(PDO)bioabsorbable stents.Methods Whole blood clotting time,prothrombin time(PT),activated partial thromboplastin time(APTT),platelet adhesion and hemolysis were used to evaluate the hemocompatibility of PDO bioabsorbable stents,and the results were compared with those of 316L stainless stents which are widely used clinically.Results The anticoagulant property of PDO bioabsorbable stents was similar to that of 316L stainless stents.Both PDO bioabsorbable and 316L stainless stents were not prone to activate blood coagulation factors.Compared with 316L stainless stents,PDO bioabsorbable stents had weaker platelet adhesion and activation.Hemolysis ratios of two groups were less than 5%.Conclusions PDO bioabsorbable stents had good hemocompatibility in vitro.