Development of self‐expandable covered stents

Abstract

We newly developed self-expandable covered stents by combining two of our original technologies. Of these, the first is the dip-coating covering method that was developed previously for balloon-expandable stents; the other is the newly developed self-expandable Nitinol stents, namely, Sendai stents. The three types of covered stents with the expansion diameter of 4.5, 5.0, or 6.0 mm thus obtained had a laser-processed microporous elastomeric cover film (pore diameter: 100 microm, interpore distance: 250 microm). Although the film was extremely thin (approximately 15 microm), the film could be expanded without causing any damage, the strut was completely embedded within the film, and the luminal surface of the film was smooth and flat. Mechanical properties such as ideal flexibility to follow the shapes of arteries were almost retained even after covering. As appropriate drugs, the blood-contacting inner and tissue-contacting outer surfaces of the film were differentially coated with argatroban for antithrombogenicity or FK506 for anti-inflammation, respectively. The preliminary in vivo study indicated that the covered stents mounted in the delivery catheter were navigated and placed to appropriate position in the arteries, and permissible neointimal thickening after 1-month implantation was observed similarly in noncovered stents.

Autologous small‐caliber “Biotube” vascular grafts with argatroban loading: A histomorphological examination after implantation to rabbits

“…Therefore, sustained release of the drug was expected after implantation. Recently, this drug has been used as an antithrombotic coating on blood‐contacting luminal surfaces of endovascular stents, where at 1 month after implantation, thin neointimal thickening with little thrombus formation was observed 11, 12. This study demonstrated the morphogenetic changes in vascular wall construction after implantation of biotubes, and the application of biotubes as small‐caliber vascular prostheses with diameters less than 2 mm was discussed.…”

Materials, fluid dynamics, and solid mechanics aspects of coronary artery stents: A state‐of‐the‐art review

“…The concept of the self‐expandable covered stent (stent coated with a segmented polyurethane film that was made microporous using KrF excimer laser)251 should be applied to both BMSs and DESs. In the latter, the luminal and outer surfaces of the microporous covered stent could be coated with drugs that have different actions, such as an antiproliferative agent and an anticoagulant.…”

“…The work reported on the mathematical modeling of the elution of a protein from a composite core fiber/protein-loaded porous shell structure (a BRS) 169 should be expanded to the case when the bioactive agent was a drug, culminating in a validated mathematical model for the elution of a drug from a composite core fiber/drug-loaded microsphere shell structure. 99 The concept of the self-expandable covered stent (stent coated with a segmented polyurethane film that was made microporous using KrF excimer laser) 251 should be applied to both BMSs and DESs. In the latter, the luminal and outer surfaces of the microporous covered stent could be coated with drugs that have different actions, such as an antiproliferative agent and an anticoagulant.…”

Layer-by-layer biofabrication of coronary covered stents with clickable elastin-like recombinamers

“…Unfortunately, the synthetic materials originally used for covering small-caliber stents (Table 1) display limited hemocompatibility, and their use has resulted in restenosis, thrombotic [8,9] and inflammatory events [10,11]. Table 1: Materials employed for the fabrication of covered coronary stents and clinical outcomes.…”