A Review on Manufacturing and Post-Processing Technology of Vascular Stents

Percutaneous coronary intervention (PCI) with stent implantation is one of the most effective treatments for cardiovascular diseases (CVDs). However, there are still many complications after stent implantation. As a medical device with a complex structure and small size, the manufacture and post-processing technology greatly impact the mechanical and medical performances of stents. In this paper, the development history, material, manufacturing method, and post-processing technology of vascular stents are introduced. In particular, this paper focuses on the existing manufacturing technology and post-processing technology of vascular stents and the impact of these technologies on stent performance is described and discussed. Moreover, the future development of vascular stent manufacturing technology will be prospected and proposed.

A tough nitric oxide-eluting hydrogel coating suppresses neointimal hyperplasia on vascular stent

Vascular stent is viewed as one of the greatest advancements in interventional cardiology. However, current approved stents suffer from in-stent restenosis associated with neointimal hyperplasia or stent thrombosis. Herein, we develop a nitric oxide-eluting (NOE) hydrogel coating for vascular stents inspired by the biological functions of nitric oxide for cardiovascular system. Our NOE hydrogel is mechanically tough and could selectively facilitate the adhesion of endothelial cells. Besides, it is non-thrombotic and capable of inhibiting smooth muscle cells. Transcriptome analysis unravels the NOE hydrogel could modulate the inflammatory response and induce the relaxation of smooth muscle cells. In vivo study further demonstrates vascular stents coated with it promote rapid restoration of native endothelium, and persistently suppress inflammation and neointimal hyperplasia in both leporine and swine models. We expect such NOE hydrogel will open an avenue to the surface engineering of vascular implants for better clinical outcomes.

Immobilization of Glycogen Synthase Kinase-3β Inhibitor on 316L Stainless Steel via Polydopamine to Accelerate Endothelialization

The coverage of stents with healthy endothelium is crucial to the success of cardiovascular stent implantation. Immobilizing bioactive molecules on stents is an effective strategy to generate such stents. Glycogen synthase kinase-3β inhibitor (GSKi) is a bioactive molecule that can effectively accelerate vascular endothelialization. In this work, GSKi was covalently conjugated on 316L stainless steel through polydopamine to develop a stable bioactive surface. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and water contact angle results revealed the successful introduction of GSKi onto 316L stainless steel. The GSKi coating did not obviously affect the hemocompatibility of plates. The adhesion and proliferation of human coronary artery endothelial cells (HCAECs) on stainless steel was significantly promoted by the addition of GSKi. In summary, this work provides a universal and stable strategy of immobilizing GSKi on the stent surface. This method has the potential for widespread application in the modification of vascular stents.

Bio-Performance of Hydrothermally and Plasma-Treated Titanium: The New Generation of Vascular Stents

The research presented herein follows an urgent global need for the development of novel surface engineering techniques that would allow the fabrication of next-generation cardiovascular stents, which would drastically reduce cardiovascular diseases (CVD). The combination of hydrothermal treatment (HT) and treatment with highly reactive oxygen plasma (P) allowed for the formation of an oxygen-rich nanostructured surface. The morphology, surface roughness, chemical composition and wettability of the newly prepared oxide layer on the Ti substrate were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDX), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle (WCA) analysis. The alteration of surface characteristics influenced the material’s bio-performance; platelet aggregation and activation was reduced on surfaces treated by hydrothermal treatment, as well as after plasma treatment. Moreover, it was shown that surfaces treated by both treatment procedures (HT and P) promoted the adhesion and proliferation of vascular endothelial cells, while at the same time inhibiting the adhesion and proliferation of vascular smooth muscle cells. The combination of both techniques presents a novel approach for the fabrication of vascular implants, with superior characteristics.

EP.WE.962Pre-emptive arterial stenting with covered vascular stents to prevent mycotic haemorrhage in infected fields following failed kidney and pancreas transplants prior to graft explant

Aims Allograft nephrectomy and pancreatectomy present a significant surgical challenge in contaminated surgical fields, with risks of post-operative pseudoaneurysms and mycotic bleeds. We report on our experience of prophylactic endovascular stenting shortly before or after allograft nephrectoym and pancreatectomy to reduce the risk of subsequent pseudoaneurysm formation from the donor arterial conduit. Methods A retrospective analysis of all patients undergoing arterial stenting by interventional radiology prior to graft explant in our unit was performed. Results Twelve patients were identified, 6 of whom had undergone kidney transplant and 6 simultaneous pancreas kidney transplant (SPK) with an average age of 46. Iliac stenting was prophylactic in 7 patients, for pseudoaneurysm (28%), graft pancreatitis (28%), acute rejection (28%), enteric anastomotic leak (16%) and transplant pyelonephritis (14%). Therapeutic stenting was performed in 5 patients, all of whom had ruptured pseudoaneurysms. Post-operative 30-day mortality occurred in 1 patient resulting from an acute on chronic limb ischaemia and subsequent sepsis and death. Of the remaining patients, none experienced complications from stenting. 9 of the 12 stented patients remain alive, with the 3 mortalities resulting from other pathology not relating to stenting. Conclusion Prophylactic iliac stenting around the time of graft excision in inflamed or infected fields provides a safe and effective technique to completely exclude the donor arterial stump, with no subsequent vascular complications reported within our series. Preventing mycotic aneurysm formation in this way may mitigate the risk of potentially catastrophic post-operative mycotic arterial bleeds.