Clinical outcomes of peripheral artery disease (PAD) stenting, particularly in the highly dynamic regions of the femoropopliteal artery at the adductor hiatus and behind the knee, leave significant room for improvement. Despite the availability of various stent designs, few are capable of accommodating the severe deformations induced by limb flexion at these locations without causing adverse stent-artery interactions. This study employed finite element analysis and response surface methodology to optimize the geometric design of nitinol PAD stents, with the objectives of improving stent-artery apposition, reducing arterial wall stress, minimizing stress concentrations, and decreasing arterial pinching under limb flexion-induced deformations. Five geometric parameters - strut width, thickness, amplitude, number, and link amplitude - were analyzed to assess their influence on stent performance. Strut width, thickness, amplitude, and the number of struts significantly impacted arterial stress and apposition, while link amplitude had an insignificant effect. We identified two optimized stent configurations that achieved > 97% stent-artery apposition, < 0.6% of the artery with stress > 100kPa, an average arterial stress of < 29kPa, and pinching of < 1.15. The findings revealed that lower strut amplitude and reduced strut cross-sections improved apposition and stress distribution but required careful balancing to minimize arterial pinching and maintain structural integrity. This study underscores the potential of multi-objective optimization in stent design, paving the way for PAD stents that more effectively accommodate femoropopliteal biomechanics and promote favorable mechanical conditions for healing.

Abluminus DES+ sirolimus-eluting stent versus everolimus-eluting stent in patients with diabetes and coronary artery disease (ABILITY Diabetes Global): results from a multicentre, randomised controlled trial.

Chiral petal honeycomb metamaterial structures: Biomimetic design and application in vascular stents.

Abstract Cardiovascular stents restore lumen patency, yet balloon-expandable designs may expand non-uniformly and traumatize vessels. A self-expandable, biodegradable stent is designed and computationally evaluated from shape-memory polymers (SMPs): poly( L -Lactic acid) (PLLA) and poly(lactic-co-glycolic acid) (PLGA). A hexagonal-nested lattice (Ø4 mm, length 40 mm, thickness 0.4 mm; rib width 0.5 mm; rib angle 120.39°; connector length 1 mm) was modeled in SOLIDWORKS and analyzed by finite elements. Physiological internal pressure (150 mmHg ≈ 0.02 MPa) assessed radial response and foreshortening across circumferential cell counts of 5, 6, and 7. Thermo-mechanical deployment followed the SMP sequence, heat to T g , cool, crimp, holding time, reheat (T g -PLLA ≈ 64 °C), to evaluate shape fixity and recovery. Reducing cells from 7 to 5 lowered peak von Mises stress (PLLA: ∼1.33 MPa–0.89 MPa), so the five-cell design was chosen for deployment. PLLA achieved high shape fixity (95 %) and near-complete recovery (&gt;99 %) with negligible expansion stresses (10 −6 MPa), indicating controlled self-deployment. PLGA showed inferior shape-memory metrics and was not advanced to detailed stress comparison. SMP-based biodegradable stents can combine low deployment stress with adequate radial support, and the presented workflow provides a reproducible computational basis for subsequent prototyping and in vitro validation.

Stent placement has become a standard intervention for occlusive luminal diseases across both vascular and non-vascular systems. Beyond their well-established use in endovascular therapy, stents play essential roles in managing obstructions in non-vascular conduits such as the airway, esophagus, urethra, ocular outflow tract, bile duct, and colon. However, conventional permanent stents are frequently associated with complications such as migration, restenosis, infection, and granulation tissue formation, which often necessitate secondary removal procedures. To overcome these limitations, biodegradable stents have emerged as a promising alternative, providing temporary mechanical support before safely degrading in situ. In parallel, drug-eluting stents offer site-specific therapeutic delivery to modulate local tissue responses, suppress fibrosis, and reduce infection risk. Although coronary stent technologies are extensively reviewed, an integrated analysis of biodegradable and drug-eluting stent innovations for non-vascular applications remains lacking. This review addresses this gap by systematically evaluating current and emerging stent technologies for major non-vascular luminal diseases. We examine the interplay between material properties, device mechanics, and the unique pathophysiological challenges of each anatomical site. We further highlight recent advances in biodegradable and drug-eluting stent design, discuss key barriers to clinical translation, and provide a forward-looking perspective on future directions in non-vascular stent development.

ABSTRACT Biliary stenting is the primary minimally invasive therapy for biliary strictures. However, the long‐term patency of conventional plastic and self‐expandable metal stents is limited by two principal failure modes: tissue‐proliferative restenosis and nonproliferative luminal occlusion. In response to these challenges, the design of functional biliary stents has evolved significantly, marking a paradigm shift from direct “active intervention” against failure mechanisms to the development of integrative “enabling platforms.” This review systematically outlines this technological and philosophical progression. Initial “active intervention” strategies are detailed, which were designed to directly counteract stent failure. These include stents engineered to inhibit tissue proliferation through the elution of chemotherapeutic agents or the incorporation of radioactive seeds for brachytherapy. Concurrently, to prevent luminal occlusion, designs have focused on mitigating duodenal reflux, modifying surface materials to inhibit biofilm formation, and modulating the biliary microenvironment. Subsequently, the review examines the transition toward next‐generation “enabling platforms,” which leverage novel materials and advanced manufacturing. Key innovations in this domain include (1) biodegradable polymer and metal‐based stents that obviate the need for subsequent removal; (2) 3D and 4D printing technologies for fabricating patient‐specific, geometrically complex, and dynamically responsive devices; (3) tissue‐engineered stents that serve as scaffolds to guide autologous bile duct regeneration; and (4) “smart” stents integrated with sensors for real‐time monitoring of patency and the local environment. The future trajectory of biliary stent technology is toward highly integrated, personalized “theranostic” systems. These platforms will likely combine biodegradability with multimodal functionalities, including targeted drug delivery, diagnostics, and regenerative capabilities. The ultimate objective is to transform biliary stenting from a palliative, foreign body implantation into a durable, physiological reconstruction of the bile duct.

Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is an emerging alternative to percutaneous transhepatic biliary drainage (PTBD) in patients with a malignant biliary obstruction, in case of technical failure of endoscopic retrograde cholangiopancreatography (ERCP). However, this procedure is technically challenging, and dedicated stents have only recently become available. This study prospectively evaluated the safety and feasibility of EUS-HGS with a dedicated stent. This prospective single-center study included patients with inoperable malignant biliary obstruction that underwent an EUS-HGS. The primary outcome was safety. Technical and clinical success were evaluated as secondary endpoints. We used a partially covered self-expandable metal stent (pcSEMS) (30% uncovered and 70% covered) with anti-migration features. EUS-HGS was attempted in 28 patients, achieving technical and clinical success rates of 89% (25/28) and 96% (22/23), respectively. Three patients (11%) experienced grade IIIA adverse events (AEs) (all cholangitis) within 30days: two with undrained right-sided bile ducts requiring percutaneous drainage, and one patient due to blockage of a side branch at the level of the covered part of the stent for which an endoscopic stent exchange was successfully performed. Five patients died < 30days due to disease progression, none of these patients experienced procedure-related AEs. Six out of the 22 patients with clinical success developed recurrent biliary obstruction after a median of 78days (IQR 45-108). Obstruction was caused by hyperplasia at the uncovered portion of the stent (n = 3) and due to sludge obstructing the stent (n = 3). Successful re-intervention was performed in all patients. This prospective study shows that EUS-HGS with a dedicated pcSEMS is feasible and safe. Tissue hyperplasia in the uncovered part of the stent and sludge obstruction may compromise long-term stent patency. Larger, comparative prospective studies are needed to assess optimal stent design and timing of EUS-HGS within the therapeutic algorithm.

This study presents a patient-specific computational analysis of hemodynamic alterations induced by stent-assisted deformation in five cerebral aneurysm models. Using high-fidelity geometrical reconstructions and computational fluid dynamics (CFD) simulations, the effects of parent vessel deformation on Wall Shear Stress (WSS), Oscillatory Shear Index (OSI), and blood flow velocity were systematically evaluated across distinct aneurysm geometries. The results demonstrate that each model exhibited a unique hemodynamic response to deformation. Model A showed an increase in WSS and OSI, indicating enhanced flow instability; Model B remained largely insensitive, displaying negligible hemodynamic variation; Model C experienced reductions in OSI and velocity, suggesting a stabilized intra-aneurysmal environment; Model D revealed a gradual decrease and redistribution of axial velocity, reflecting attenuation of inflow momentum; and Model E exhibited a pronounced redirection of the inflow jet and asymmetric velocity field, accompanied by a moderate decline in flow magnitude. Overall, these findings emphasize the critical role of aneurysm morphology and vessel curvature in modulating post-treatment hemodynamics and reinforce the need for patient-specific computational modeling to guide stent design and placement for improved clinical outcomes in cerebral aneurysm management.

Comparative biomechanical and structural evaluation of region-specific stented and non-stented ex vivo perfused human thoracic aortas.

Vascular Response After Stenting of the Renal Arteries in Pigs Using an Absorbable Sirolimus-Eluting Polymer Scaffold.

Transcatheter mitral valve replacement (TMVR) faces challenges of stent migration and left ventricular outflow tract (LVOT) obstruction. Traditional stents fail to meet the demands of systolic high pressure, dynamic saddle-shaped annular contraction, and diastolic LVOT protection, while auxiliary anchoring devices may cause tissue damage. To address these issues, we propose a dual-layer lantern-shaped nitinol stent (L-NiTi) with a pressure-responsive diameter modulation. Using SAPIEN 3 Ultra cylindrical cobalt-chromium (C-CoCr) and cylindrical nitinol (C-NiTi) stents as controls, we constructed a finite element native valve stent prosthesis interaction model under cardiac cycle pressure loading to quantify the performance of the stents. Results showed that the L-NiTi exhibited a maximum strain of 8.9%, a 9.17% ± 3.12% loss in prosthetic leaflet area (compared to a 23% loss in controls), a 34 N increase in systolic migration resistance, and an axial displacement of 1.28mm (compared to 2.16 and 4.78mm in C-CoCr and C-NiTi controls, respectively). The improved asymmetric lantern-shaped stent maintained a 32 N increase in migration resistance while increasing the neo-LVOT area from 2.52 to 2.81 cm2. The proposed new design of stent for TMVR enhances anchoring without compromising LVOT, demonstrating translational potential for TMVR.

Design, Biomechanical Performance, and Physiological Considerations of Esophageal Stents in Relation to Esophageal Peristalsis: A Review

Background: Postoperative leakage at the esophagogastric anastomosis is a well-recognized and significant complication following esophagectomy. In the past, treatment options were largely confined to either conservative, nonsurgical management or removal of the gastric conduit with construction of a cervical esophagostomy. Over the last decade, the development of endoluminal stents and endoscopic clipping techniques has provided a less invasive alternative, enabling effective closure of leaks without the need for further surgery and preserving the continuity of the reconstructed esophagus. Methods: This report presents our initial clinical experiences with the combined use of stents and clips. It also reviews up-to-date evidence on patient selection, available stent designs, treatment success rates, procedure-related considerations, and the anticipated role of endoscopic approaches in managing postoperative esophagogastric anastomotic leakage. Results: We report 3 cases who underwent endoscopic management for esophagogastric anastomotic leak with a combination of stent and clips. The success of the procedure was determined on the extent of the defect and source management, which frequently necessitated concurrent drainage and antibiotic therapy. Conclusions: Conservative approaches have become increasingly significant in the treatment of anastomotic leaks following esophageal surgery. Our experience demonstrates that some challenging cases can be treated with a combination of endoscopic therapy methods.

Establishing an optimal first-line approach for suspected intracranial atherosclerotic disease (ICAD)-related acute large vessel occlusion (LVO) remains challenging. We developed an ICAD model using an agarose phantom to investigate the specific features of the stent retriever (SR) design for ICAD-LVO for safety use. An ICAD model that reproduced the mechanical features of plaque was developed to quantify the pull-out resistance and intraluminal injury caused by SRs. The impacts of vessel factors (ICAD existence and plaque stiffness) and SR design (non-segmented, segmented, and manually-controllable-diameter) were evaluated using this model. In the 6% agarose (as soft plaque) ICAD model, SR caused significantly higher pull-out resistance and severe intraluminal injury compared with the non-ICAD model or the 10% agarose (as hard plaque) ICAD model with almost all SRs. In the 6% ICAD model, non-segmented, rather than segmented, SRs seemed to reduce pull-out resistance and intraluminal injury. Longer SRs strengthened the benefit of non-segmented design. SRs with manually controllable diameter, when fully relaxed before retrieval, seemed to provide the safest option among all SR designs, while those with usual handling such as slight relaxation before retrieval seemed to be the most harmful due to specific deformation. Using SRs for ICAD-LVO may increase pull-out resistance and intraluminal injury, particularly in ICAD involving soft plaques. SR use safety for ICAD seems to depend largely on SR design and handling procedures of manually controllable diameter SRs.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-24696-z.

Carotid artery stenting (CAS) is an established alternative to endarterectomy, but stent fracture is an under-recognized complication with potential clinical consequences. We report a case of carotid stent fracture in a 69-year-old male with prior neck radiation, presenting with severe in-stent restenosis 10 months post-stenting. To place this case in context, a systematic review of PubMed, Embase, and Scopus (through June 2025) was conducted in line with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Ten retrospective studies (2365 patients) were included. Stent fracture was identified in 172 patients, with a pooled prevalence of 7.3%. Type I and II fractures were most common, while Type V was rare. Reported risk factors included prior neck irradiation, vessel tortuosity, long stent length, and closed-cell stent design. Fluoroscopy was the most reliable detection method. Restenosis rates varied widely (0%-36%), most patients remained asymptomatic and were managed conservatively. In conclusion, Carotid stent fracture occurs in approximately 7% of cases and is often clinically silent, though it may predispose to restenosis. Surveillance and management should be individualized, with intervention reserved for symptomatic patients or progressive disease.

BackgroundOral stents may reduce toxicities during radiation therapy for head and neck cancer (HNC). Customized 3D-printed oral stents offer faster production and achieve comparable patient-reported outcomes to conventionally fabricated stents. However, their design process remains time-consuming, lacks standardization, and relies heavily on skilled technicians. We hypothesized that semi-automating the design process for 3D-printed, mouth-opening, tongue-depressing (MOTD) stents could standardize the design workflow and decrease design time.MethodsUsing oral stent design principles established over decades by oral oncologists, we created a customized computer program (Autostent) using MATLAB to semi-automate the design process of MOTD stents. We subsequently compared Autostent to a previously described method that utilized non-automated computer-aided design. Three users designed stents for four patients with HNC enrolled in a prospective observational study. These patients were selected based on their varying dental anatomies, and each user repeatedly designed an MOTD stent for each patient three times, employing both the non-automated and semi-automated methods. Both methods were compared in terms of design time and stent volume.ResultsSemi-automation reduced the average design time by 23.6 min (51.2%, p = 0.001), regardless of user, dental anatomy, or trial number. Additionally, semi-automation decreased the average stent volume by 4.33 mL (12.9%, p = 0.016, univariate analysis). Although this reduction was not statistically significant when considering other experimental variables (p = 0.40, multivariate analysis), semi-automation did lower the variability in stent volume among users (the overall standard error of the mean decreased by 40%).ConclusionOur semi-automated workflow for designing and fabricating customized, 3D-printed MOTD stents significantly improves efficiency and reduces variability in the design. While these results indicate greater consistency compared to manual methods, further development is warranted to achieve full automation and to optimize clinical integration.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13014-025-02727-3.

Complex coronary bifurcation lesions remain challenging in percutaneous coronary intervention, with stent design and deployment strategy influencing clinical outcomes. This study compares the mechanical and hemodynamic performance of the ultrathin-strut Orsiro and thin-strut Xience Sierra stent in provisional side branch (PSB) and double kissing crush (DKC) techniques. We used finite element analyses of bifurcation stent deployment to assess malapposition, ostium clearance, and arterial wall stress for both techniques. Computational fluid dynamics simulations quantified the luminal exposure to low time-averaged endothelial shear stress (TAESS < 0.4 Pa) and high shear rates (> 1000 s⁻¹). In PSB, Orsiro showed higher malapposition (13.0% vs. 9.6%) but improved SB ostium clearance (77% vs. 64%) and lower low-TAESS exposure (30.3% vs. 33.6%) compared to Xience. Orsiro also produced higher arterial wall stresses, particularly during kissing balloon inflation. In DKC, differences in malapposition and ostium clearance diminished between stents, though Orsiro retained a hemodynamic advantage with lower low-TAESS (28.2% vs. 36.3%). Stent design influenced outcomes more strongly in PSB, where anatomical interaction and platform-specific behavior impacted both structural and hemodynamic results. In DKC, procedural complexity minimized those differences, making the stenting technique the primary performance driver. Nonetheless, Orsiro consistently preserved more favorable flow conditions. These findings highlight the need to match device selection with lesion characteristics in PSB, while in DKC, optimizing procedural steps may have a greater impact than the choice of stent platform.

Background and study aimsBiliary stents are widely used in endoscopic retrograde cholangiopancreatography (ERCP), yet their impact on the native bile microbiome under non-infectious conditions remains unclear. We aimed to characterize stent-associated alterations in the biliary microbiome using 16S rRNA gene sequencing.Patients and methodsWe analyzed bile samples collected during ERCP from 35 patients without clinical or laboratory evidence of acute cholangitis. Patients were categorized into a control group (n = 25; naïve papillae) and an endoscopic biliary stenting (EBS) group (n = 10; previously stented). Microbial composition was assessed using high-throughput 16S rRNA sequencing after propensity score matching to balance background characteristics.ResultsBeta diversity differed significantly between groups (PERMANOVA,P< 0.01), despite no significant differences in alpha diversity. The EBS group demonstrated increased relative abundance ofFirmicutesandFusobacteriota, and depletion ofProteobacteria. Notably,Enterococcuswas significantly enriched in the EBS group (log fold change 6.74;q< 0.01), whereasSphingomonaswas reduced.ConclusionsEndoscopic biliary stenting is associated with distinct bile microbiome alterations, characterized by enrichment ofEnterococcusspecies in clinically stable patients. These findings suggest that stents may predispose to opportunistic colonization, providing a potential mechanistic link to future cholangitis. Recognizing such preclinical dysbiosis may inform tailored antimicrobial strategies and future stent design.

The application of metal ureteral stents emerges as a promising therapeutic alternative for complex ureteral strictures. Nevertheless, the conventional segmented stent design predisposes to complications such as migration and urothelial hyperplasia, leading to treatment failure. This study introduced an innovative head-tail stress-free (HTSF) technique and to compare the long-term effectiveness and safety between HTSF and traditional segmented placement. This retrospective cohort analysis evaluated 417 patients undergoing ureteral stent placement (HTSF technique: n=258; traditional method: n=159) with a minimum follow-up of 24months. In the traditional group, metal stents were positioned with ≥ 2cm extension beyond stricture margins at both ends. In the HTSF group, two or more metal stents were placed to ensure that head-tail ends of stents resided within a large lumen. The median follow-up times were 32.0 and 27.0months in the traditional and HTSF groups, respectively. HTSF placement achieved a significant higher success rate (89.5% vs. 45.9%, P<0.001), a lower rate of stent migration (5.4% vs. 44.0%, P<0.001), and occlusion (1.9% vs. 6.3%, P=0.020). Under ureteroscopy, the HTSF group exhibited a lower rate of urothelial hyperplasia (1.9% vs. 29.6%, P<0.001). Furthermore, the HTSF group had a slightly lower score of Ureteral Stent Symptoms Questionnaire (USSQ) (P=0.040) and greater relief in hydronephrosis volume (P=0.013). The HTSF technique significantly improved success rates while reducing the incidence of stent migration, occlusion, and urothelial hyperplasia. Moreover, HTSF did not exacerbate stent-related symptoms and contributed to improved long-term satisfaction.

Despite advances in stent technology, in-stent restenosis remains a critical challenge following percutaneous coronary intervention. In this work, we propose a comprehensive fluid-solid computational model to simulate restenosis after drug-eluting stent implantation. We develop a three-dimensional continuum-based framework that couples the complex interplay of hemodynamics, pharmacokinetics, and restenosis-induced arterial growth. Within the arterial wall, a continuum model of cell dynamics and tissue growth predicts neointimal thickening. Drug release is modeled by direct diffusion from the abluminal stent surface and one-way absorption of hydrophobic drug from the bloodstream at the lumen-wall interface. We incorporate blood flow influence into growth mechanics through the effect of non-physiological wall shear stresses on endothelial cells morphology. Due to the short time scale inherent in the fluid model, we adopt a quasi-steady approach that efficiently homogenizes hemodynamic-related quantities over clinically relevant time scales for restenosis and drug release. We verify the components of the computational model and the quasi-steady assumption using a test case with an idealized cylindrical artery and a one-ring stent. The framework is further extended to patient-specific geometries obtained from optical coherence tomography and virtual stent implantation. Our results showcase how stent design, drug elution, and hemodynamics can collectively modulate restenosis progression, and the proposed coupling framework could, in the long term, contribute to the development of clinical decision-support tools.