Bioresorbable Scaffold Research Articles

Additive Manufacturing of Biodegradable Molybdenum - From Powder to Vascular Stent.

Magnesium, iron, and zinc-based biodegradable metals are widely recognized as promising candidate materials for the next generation of bioresorbable stent (BVS). However, none of those metal BVSs are perfect at this stage. Here, a brand-new BVS based on a novel biodegradable metal (Molybdenum, Mo) through additive manufacturing is developed. Nearly full-dense and crack-free thin-wall Mo is directly manufactured through selective laser melting (SLM) with fine Mo powder. Systemic analyses considering the forming quality, wall-thickness, microstructure, mechanical properties, and in vitro degradation behaviors are performed. Then, Mo-based thin-strut (≤ 100µm) stents are successfully obtained through an optimized single-track laser melting route. The SLMed thin-wall Mo owns comparable strength to its Mg and Zn based counterparts (as-drawn), while, it exhibits remarkable biocompatibility in vitro. Vessel related cells are well adhered and spread on SLMed Mo, and it exhibits a low risk of hemolysis and thrombus. The SLMed stent is compatible to vessel tissues in rat abdominal aorta, and it can provide sufficient support in an animal model as an extravascular stent. This work possibly opens a new era of manufacturing Mo-based stents through additive manufacturing.

Conceptualizing Scaffold Guided Breast Tissue Regeneration in a Preclinical Large Animal Model.

Scaffold-guided breast tissue regeneration (SGBTR) can transform both reconstructive and cosmetic breast surgery. Implant-based surgery is the most common method. However, there are inherent limitations, as it involves replacement of tissue rather than regeneration. Regenerating autologous soft tissue has the potential to provide a more like-for-like reconstruction with minimal morbidity. Our SGBTR approach regenerates soft tissue by implanting additively manufactured bioresorbable scaffolds filled with autologous fat graft. A pre-clinical large animal study was conducted by implanting 100 mL breast scaffolds (n = 55) made from medical-grade polycaprolactone into 11 minipigs for 12 months. Various treatment groups were investigated where immediate or delayed autologous fat graft, as well as platelet rich plasma, were added to the scaffolds. Computed tomography and magnetic resonance imaging were performed on explanted scaffolds to determine the volume and distribution of the regenerated tissue. Histological analysis was performed to confirm the tissue type. At 12 months, we were able to regenerate and sustain a mean soft tissue volume of 60.9 ± 4.5 mL (95% CI) across all treatment groups. There was no evidence of capsule formation. There were no immediate or long-term post-operative complications. In conclusion, we were able to regenerate clinically relevant soft tissue volumes utilizing SGBTR in a pre-clinical large animal model.

Sirolimus-eluting iron bioresorbable scaffold versus cobalt-chromium everolimus-eluting stents in patients with coronary artery disease: Rationale and design of the IRONMAN-II trial

BackgroundThe previous first-in-human study established the preliminary safety and effectiveness of the novel thin-strut iron bioresorbable scaffold (IBS). The current study aims to directly compare the imaging and physiological efficacy, and clinical outcomes of IBS with contemporary metallic drug-eluting stents (DES). MethodsA total of 518 patients were randomly allocated to treatment with IBS (257 patients) or metallic DES (261 patients) from 36 centers in China. The study is powered to test noninferiority of the IBS compared with the metallic everolimus-eluting stent in terms of the primary endpoint of in-segment late lumen loss at 2 years, and major secondary endpoints including 2-year quantitative flow ratio and cross-sectional mean flow area measured by optical coherence tomography (OCT) (limited to the OCT subgroup, 25 patients in each group). ConclusionThis will be the first powered randomized trial investigating the safety and efficacy of the novel thin-strut IBS compared to a contemporary metallic DES. The findings will provide valuable evidence for future research of this kind and the application of metallic bioresorbable scaffolds.

Developing Zn-2Cu-xLi (x < 0.1 wt %) alloys with suitable mechanical properties, degradation behaviors and cytocompatibility for vascular stents

Biodegradable Zn alloys show great potential for vascular stents due to their moderate degradation rates and acceptable biocompatibility. However, the poor mechanical properties limit their applications. In this study, low alloyed Zn-2Cu-xLi (x = 0.004, 0.01, 0.07 wt %) alloys with favorable mechanical properties were developed. The microstructure consists of fine equiaxed η-Zn grains, micron, submicron-sized and coherent nano ε-CuZn4 phases. The introduced Li exists as a solute in the η-Zn matrix and ε-CuZn4 phase, and results in the increase of ε-CuZn4 volume fraction, the refinement of grains and more uniform distribution of grain sizes. As Li content increases, the strength of alloys is dramatically improved by grain boundary strengthening, precipitate strengthening of ε-CuZn4 and solid solution strengthening of Li. Zn-2Cu-0.07Li alloy has the optimal mechanical properties with a tensile yield strength of 321.8 MPa, ultimate tensile strength of 362.3 MPa and fracture elongation of 28.0 %, exceeding the benchmark of stents. It also has favorable mechanical property stability, weak tension compression yield asymmetry and strain rate sensitivity. It exhibits uniform degradation and a little improved degradation rate of 89.5 μm∙year−1, due to the improved electrochemical activity by increased ε-CuZn4 volume fraction, and generates Li2CO3 and LiOH. It shows favorable cytocompatibility without adverse influence on endothelial cell viability by trace Li+. The fabricated microtubes show favorable mechanical properties, and stents exhibit an average radial strength of 118 kPa. The present study indicates that Zn-2Cu-0.07Li alloy is a potential and promising candidate for vascular stent applications. Statement of significanceZn alloys are promising candidates for biodegradable vascular stents. However, improving their mechanical properties is challenging. Combining the advantages of Cu and trace Li, Zn-2Cu-xLi (x < 0.1 wt %) alloys were developed for stents. As Li increases, the strength of alloys is dramatically improved by refined grains, increased volume fraction of ε-CuZn4 and solid solution of Li. Zn-2Cu-0.07Li alloy exhibits a TYS exceeding 320 MPa, UTS exceeding 360 MPa and fracture EL of nearly 30 %. It shows favorable mechanical stability, degradation behaviors and cytocompatibility. The alloy was fabricated into microtubes and stents for mechanical property tests to verify application feasibility for the first time. This indicates that Zn-2Cu-0.07Li alloy has great potential for vascular stent applications.

Biodegradable Biliary Stents. Materials and Methods for Evaluating Functional Properties. A Review

Biodegradable Biliary Stents. Materials and Methods for Evaluating Functional Properties. A Review

A biodegradable polymer stent with high radial performance: Potential for treatment of portal vein stenosis

AbstractBiodegradable polymer stents have a wide application prospect in the treatment of vascular stenosis diseases. However, weak radial performance of polymer stents hinders the treatment of the diseases with high demand for radial supporting, such as portal vein stenosis. According to previous research, the constraint mode between monofilaments is a key factor that affects the radial performance of polymer braided stent. In this work, a series of Poly(l‐lactic acid) (PLLA) stents with the elastomer coating were prepared by ultrasonic spraying process to realize the constraints of monofilament cross points. The results are showed that the radial stiffness and peak force of the coated stent are significantly increased, up to 28 and 35 times higher than that of the bare stent. It is found that the cross points are constrained by the coating, which improves the constraining force between the monofilaments resulting in the increase of the radial force during the deformation process. More importantly, the mechanism of action between the radial force of the coated stent and the mechanical performance of elastic coating has been proposed, revealing a significant positive correlation between them. The radial force of the coated stent could be quantitatively regulated by the six‐arm poly(l‐lactide‐co‐ε‐caprolactone) (6SPLCL) coating cross‐linked by Hexamethylene diisocyanate (HDI) in different proportions. Finally, we build a mechanical model of stents and find that there is a consistency between the theoretical curve and the actual curve trend. This provides further research and expands the application scope for improving the radial supporting performance of the biodegradable polymer stent.

Degrees of Inflammation in the Treatment of Subglottic Stenosis in a Rabbit Model: Histopathological Assessment of a Novel Bioabsorbable Ultra-high Ductility Magnesium Alloy Stent

ObjectiveUtilizing a novel histopathological scoring system and subglottic stenosis (SGS) rabbit model, we aimed to compare degrees of inflammation and severity of narrowing in the subglottis between two minimally invasive therapeutic modalities: endoscopic balloon dilation (EBD) alone versus EBD with placement of a bioabsorbable ultra-high ductility magnesium (UHD-Mg) alloy stent. MethodsSGS was induced endoscopically via microsuspension laryngoscopy in 23 New Zealand white rabbits. The control group (n = 11) underwent EBD alone, the study arm (n = 12) underwent EBD with implantation of bioabsorbable UHD-Mg alloy stents. Rabbits were euthanized at 2-, 3-, and 6-weeks after SGS induction, coinciding with wound healing stages. Using Optical Coherence Tomography (OCT), cross-sectional areas of airways were compared to calculate the mean percentage of intraluminal area at sequential time points. A novel histopathological scoring system was used to analyze frozen sections of laryngotracheal complexes. The degree of inflammation was quantified by scoring changes in inflammatory cell infiltration, epithelial ulceration/metaplasia, subepithelial edema/fibrosis, and capillary number/dilation. Univariate analysis was utilized to analyze these markers. ResultsWe found rabbits implanted with the bioabsorbable UHD-Mg alloy stent had statistically significantly higher scores in categories of hyperplastic change (stents vs controls: 1.48 vs 0.46 p < 0.001), squamous metaplasia (22 vs 5 p < 0.001), and neutrophils/fibrin in lumen (31 vs 8, p < 0.001). Rabbits who received EBD alone had higher scores of subepithelial edema and fibrosis (2.70 vs 3.49, p < 0.0256). The stented rabbits demonstrated significantly increased mean percent stenosis by intraluminal mean area compared to controls at 2 weeks (88.56 vs 58.98, p = 0.032), however at all other time points there was no significant difference between intraluminal subglottic stenosis by mean percent stenosis area. DiscussionRabbits with SGS treated with UHD-Mg alloy stents demonstrated histopathologic findings suggestive of lower levels of tracheal fibrosis. This could indicate a reduced tendency towards the development of stenosis when compared to EBD alone. There was not a difference in luminal size between stent and non-stented rabbits at the six-week end point. Histologically, however, overall the use of bioabsorbable UHD-Mg alloy stenting elicited a greater tissue response at the level of the superficial mucosa rather than fibrosis of the lamina propria seen in the stented rabbits. This suggests more favorable healing and less of a tendency towards fibrosis and stenosis even though there may not be a benefit from a luminal size standpoint during this early healing period. Compared to known complications of currently available non-bioabsorbable metal or silicone-based stents, this proof-of-concept investigation highlights the potential use of a novel biodegradable UHD-Mg stent as a therapeutic modality for pediatric SGS.

One-Month Dual Antiplatelet Therapy Followed by P2Y12 Inhibitor Monotherapy After Biodegradable Polymer Drug-Eluting Stent Implantation - The REIWA Region-Wide Registry.

The safety and feasibility of using 1-month dual antiplatelet therapy (DAPT) followed by P2Y12inhibitor monotherapy for patients after percutaneous coronary intervention (PCI) with thin-strut biodegradable polymer drug-eluting stents (BP-DES) in daily clinical practice remain uncertain.Methods and Results: The REIWA region-wide registry is a prospective study conducted in 1 PCI center and 9 local hospitals in northern Japan. A total of 1,202 patients who successfully underwent final PCI using BP-DES (Synergy: n=400; Ultimaster: n=401; Orsiro: n=401), were enrolled in the registry, and received 1-month DAPT followed by P2Y12inhibitor (prasugrel 3.75 mg/day or clopidogrel 75 mg/day) monotherapy. The primary endpoint was a composite of cardiovascular and bleeding events at 12 months, including cardiovascular death, myocardial infarction (MI), definite stent thrombosis (ST), ischemic or hemorrhagic stroke, and Thrombolysis in Myocardial Infarction (TIMI) major or minor bleeding. Based on the results of a previous study, we set the performance goal at 5.0%. Over the 1-year follow-up, the primary endpoint occurred in 3.08% of patients, which was lower than the predefined performance goal (Pnon-inferiority<0.0001). Notably, definite ST occurred in only 1 patient (0.08%) within 1 year (at 258 days). No differences were observed in the primary endpoint between stent types. The REIWA region-wide registry suggests that 1-month DAPT followed by P2Y12inhibitor monotherapy is safe and feasible for Japanese patients with BP-DES.

Symmetrical structure design of PLGA Biodegradable sinus stents and structure optimization based on surrogate models.

This study aims to enhance the degradation uniformity of PLGA sinus stents to minimize fracture risk caused by stress corrosion. Symmetric stent structures were introduced and compared to sinusoidal structure in terms of stress and degradation uniformity during implantation and degradation processes. Three surrogate models were employed to optimize the honeycomb-like structure. Results showed honeycomb-like structures exhibited the superior stress distribution and highest degradation uniformity. The kriging model achieved the smallest error and degradation uniformity of 83.24%. In conclusion, enhancing the symmetry of stent structures improves degradation uniformity, and the kriging model has potential for the optimization of stent structures.

Peripheral vascular bioresorbable scaffolds: Past, present, and future

As peripheral vascular disease affects more and more people in the world, interventional treatment of peripheral blood vessels evolves from percutaneous transluminal angioplasty to bioresorbable vascular scaffolds (BVS). At present, the materials of peripheral vascular bioresorbable scaffolds mainly include polymers and metal materials, and have achieved certain clinical application effects. Examples of these BVS are provided, and their advantages and defects are discussed. Poly-L-lactic acid is most commonly used in polymer BVS. There have been some polymer BVS entering clinical research for peripheral blood vessels since the 10 s, and have various outcomes. Metal materials for BVS mainly include magnesium alloy, iron alloy, and zinc alloy. The improved magnesium alloy BVS show excellent antiplatelet adhesion ability and can reduce the formation of acute stent thrombosis in clinical research. The iron alloy BVS and zinc alloy BVS also show excellent performance in animal experiments. The drug coating of BVS is expected to be improved. Finally, prospects of future development are highlighted. With the continuous improvement of manufacturing and drug-coating process, their therapeutic effect is expected to continue to improve.

Two-Year Outcomes for Patients with Non-ST-Elevation Acute Coronary Syndrome Treated with Magmaris and Absorb Bioresorbable Scaffolds in Large-Vessel Lesions.

The acute coronary syndrome (ACS) continues to be a fundamental indication for revascularization by percutaneous coronary intervention (PCI). Drug-eluting stent (DES) implantation remains a part of contemporary practice but permanent caging of the vascular structure with the metallic stent structure may increase the rate of device-related adverse clinical events. As an alternative to classic metallic DESs, the bioresorbable scaffolds (BRSs) have emerged as a temporary vascular support technology. We evaluated the mid-term outcomes of two generations of bioresorbable scaffolds-Absorb (Abbott-Vascular, Chicago, IL, USA) and Magmaris (Biotronik, Germany)-in patients with non-ST-elevation ACS. The study cohort consisted of 193 subjects after Magmaris implantation and 160 patients following Absorb implantation in large-vessel lesions. At 2 years, a significantly lower rate of a primary outcome (cardiac death, myocardial infarction, stent thrombosis) was observed with Magmaris (5.2% vs. 15%; p = 0.002). In addition, we observed a significantly lower rate of MI in the target vessel (2.6% vs. 9.4%; p = 0.009) and a lower rate of scaffold thrombosis (0% vs. 3.7%; p = 0.008). The TLF rate between the two groups was not significantly different. Magmaris demonstrated a good safety profile and more favorable clinical outcomes when compared to Absorb in patients with non-ST-elevation ACS.

In Silico Evaluation of In Vivo Degradation Kinetics of Poly(Lactic Acid) Vascular Stent Devices.

Biodegradable vascular stents (BVS) are deemed as great potential alternatives for overcoming the inherent limitations of permanent metallic stents in the treatment of coronary artery diseases. The current study aimed to comprehensively compare the mechanical behaviors of four poly(lactic acid) (PLA) BVS designs with varying geometries via numerical methods and to clarify the optimal BVS selection. Four PLA BVS (i.e., Absorb, DESolve, Igaki-Tamai, and Fantom) were first constructed. A degradation model was refined by simply including the fatigue effect induced by pulsatile blood pressures, and an explicit solver was employed to simulate the crimping and degradation behaviors of the four PLA BVS. The degradation dynamics here were characterized by four indices. The results indicated that the stent designs affected crimping and degradation behaviors. Compared to the other three stents, the DESolve stent had the greatest radial stiffness in the crimping simulation and the best diameter maintenance ability despite its faster degradation; moreover, the stent was considered to perform better according to a pilot scoring system. The current work provides a theoretical method for studying and understanding the degradation dynamics of the PLA BVS, and it could be helpful for the design of next-generation BVS.

REVASCULARIZATION WITHOUT DES: A CASE REPORT ABOUT METALLIC–LESS REVASCULARIZATION TECHNIQUES

Abstract Rational 56 years old patient, admitted to our service for myocardial infarction without ST elevation. In medical history he had dyslipidaemia, hypertension and familiarity for cardiovascular disease, without previous cardiological problems. The patient went to the ER for chest pain, started after his work shift. When admitted to the ER, the patient was still symptomatic for chest pain, with resolution after 3 hours after somministration of analgesics, with normal pressure and heart rate. An ECG was performed, without relevant findings, at the blood exams significative movement of cardiac troponins. At the echocardiogram apical hypokinesia of left ventricle with preserved ejection fraction. Technical Resolution Coronarography was performed, with evidence of severe diffuse atheromatic disease of the left anterior descending artery (LAD) at the proximal segment and sub–occlusive stenosis at the middle segment. Due to the diffuseness of the atherosclerotic disease on the LAD, which would have required a complete stenting of the artery, which using classical Drug Eluted Stents would have led to a complete metallization of the artery, in such a young patient who does not have medical history suggesting a progression of the atheromatic disease, metallic–less techniques were chosen. The two lesions were pre–dilatated with a non–compliant (NC) balloon. The proximal lesion was treated with a bioresorbable scaffold (BVS) Magmaris 3x25 mm, post–dilatated with a NC balloon, without complications. The distal segment was treated with a Drug Eluting Balloon (DEB) Pantera Lux 2.5x20 mm, expanded for 90 seconds, with evidence of focal dissection, not flow limiting.At the clinical follow–up performed at one and three months, the patient was asymptomatic for angina, without any cardiovascular event. Clinical Implications When facing coronaropathy in a young patient, it is a good option to treat the coronary with techniques that do not leave metallic material in the arteries, which exposes young patients to a higher rate of complications if compared to older patients. When it is preferred to use this kind of techniques, the options can be DEB or BVS. As seen in this case report, often the DEB can lead to complications. It’s well–known that every DEB complication needs a DES to fix it. However, little is proven and studied about the use of BVS on de–novo lesions and on coronary injuries as complications of “conventional” PCI, as well as those derived from DEB delivery.

Biodegradable tracheal stents: our ten-year experience with adult patients

BackgroundBiodegradable (BD) stents made from polydioxanone have been used only in human airways. These stents combine the advantages of classical tracheal stents, and fewer side effects are expected due to their biocompatibility and their time-limited presence in airways. However, new clinical consequences have arisen. Here, the authors share their experiences with BD stents for tracheal indications, focusing on their safety and efficacy.MethodsThis was a retrospective review of a collected database of adult patients who underwent implantation of biodegradable tracheal stents between September 2013 and December 2022 at the Department of Respiratory Medicine of the 1st Faculty of Medicine in Prague and Thomayer University Hospital. The indications included functionally significant nonmalignant tracheal stenosis and tracheomalacia. Self-expandable, biodegradable, polydioxanone tracheal stents manufactured by ELLA-CS Ltd. (Hradec Kralove, Czech Republic) were implanted during rigid bronchoscopy under general anaesthesia. All patients were followed up in the department and were provided with the necessary care. The main efficacy and safety parameters and relationships were analysed using descriptive statistics and Fisher´s exact, Wilcoxon and Kruskal‒Wallis tests.ResultsA total of 65 stents were implanted in 47 adult patients. During the first two months after implantation, when adequate function was expected, the stent was found to be effective in 26 out of 39 patients who completed this period (66.7%). The clinical effectiveness reached 89.7%, as early restenoses were mostly mild and necessitated treatment in only 4 patients. The frequencies of significant mucostasis, migration and granulation tissue growth were 2.6%, 7.5% and 23.1%, respectively, during this period. Thirty-four participants completed the half-year follow-up period after the first or second stent insertion, and some were followed up beyond this period. Poor control of symptoms, the development of restenosis and the need for interventions were characteristic of this period as the stents degraded. Twenty-two patients who experienced remodelling or stabilization of the tracheal lumen achieved a stent-free state. Seven patients underwent subsequent surgical treatment.ConclusionsBD stents are safe and provide adequate tracheal support until they begin to degrade. The use of BD stents necessitates close monitoring of patients and accurate treatment of possible restenosis.Trial registrationBased on project NT14146 – Biodegradable stents in the management of the large airways (2013–2015, MZ0/NT), registered on May 1, 2013, in the Research and Development and Innovation Information System of the Czech Republic and at ClinicalTrials.gov (reg. no. NCT02620319, December 2, 2015).

Thrombogenicity of biodegradable metals

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent metals. While numerous biodegradable metal alloys have been developed and characterized in animal models, knowledge of their blood reactivity and thrombogenicity remains unknown. Metal hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis risk. In this study, four pure metals, widely used as degradable base materials (Fe, Zn, Mg, and Mo), and three alloys commonly used in cardiovascular devices [NiTi, CoCr, and stainless steel (SS)] were evaluated. This work examined how each of these metals activate platelets, coagulation factors, and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt model. Testing found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood, platelet and fibrin attachment to Mg was markedly reduced. Additionally, Fe and Mo trended toward higher platelet attachment and contact pathway activation. Overall, the results suggest that Mg may delay clot initiation, but not eliminate clot formation, indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

3D printed stents using Fused deposition modelling

3D printing has emerged as an appealing technology for designing and manufacturing bioresorbable stents. This innovative technology enables the creation of a diverse range of stent structures with specific features and intricate geometries, significantly impacting their mechanical properties and potentially affect clinical performance. In this study, we investigated the influence of various processing parameters during the 3D printing process and assess their effects on stent quality. Fused Deposition Modelling (FDM) was chosen as the 3D printing technology, with a focus on optimizing the printing of a novel chevron-strut stent design. Printing parameters were systematically investigated to understand their individual contributions to overall stent quality. The findings reveal the significance of print speed (6.5 mm/s) as a pivotal factor, influencing strut width and the difference between the Computer Aided Design (CAD) volume to calculated volume of stent. Furthermore, the optimization of printing parameters such as travel speed (200 mm/s), and line width (0.2 mm) led to the fabrication of stent with strut widths of 400 μm. However, it is important to also consider other parameters for comprehensive print optimization. In conclusion, by exercising control over the print process parameters, it becomes feasible to produce stents that closely align with the original CAD designs.

One-Year Outcomes of Biodegradable Polymer-Coated Sirolimus-Eluting Coronary Stent in Acute Coronary Syndrome: A Patient-Level Pooled Analysis from Two Indian Registries

Introduction: This pooled analysis was conducted to assess the clinical safety and performance of the Supra family (Sahajanand Medical Technologies Ltd., Surat, India) of sirolimus-eluting stents (SES) in patients with acute coronary syndromes (ACSs) including ST-segment elevation myocardial infarction (STEMI) from two real-world all-comers Indian registries at 1 year. Methods: We evaluated 1,824 patients with ACS who underwent percutaneous coronary intervention with the Supra family of SES from two real-world Indian registries (891 patients from T-Flex registry and 933 patients from Tetriflex real-world registry). The primary endpoint was the incidence of target lesion failure (TLF) defined as a composite of cardiac death, target-vessel myocardial infarction (TV-MI), and target lesion revascularization (TLR) at 1-year follow-up. The safety endpoint was stent thrombosis at 1-year follow-up. Results: Among a total of 1,824 patients with ACS, 689 (37.8%) patients presented with STEMI. In ACS and STEMI groups, 47.6% and 41.8% patients had multivessel disease, respectively. Of 2,128 lesions in ACS group, 76.7% lesions were type B2/C and 16.2% lesions were totally occluded. In the STEMI group, out of 784 treated lesions, 76.7% were type B2/C lesions and 21.9% were totally occluded. At 1-year follow-up, incidence of TLF was 5.3% (cardiac death: 0.9%, TV-MI: 2.5%, TLR: 1.9%) in patients with ACS and 6.2% (cardiac death: 1.4%, TV-MI: 2.1%, TLR: 2.7%) in patients with STEMI. The 1-year rate of definite/probable stent thrombosis was 0.3% and 0.7% in patients with ACS and STEMI, respectively. Conclusion: This patient-level pooled analysis provides evidence for the safe and effective use of the Supra family of SES in complex patient populations such as ACS and even in STEMI with favorable rates of TLF and stent thrombosis at 1-year follow-up.

Safety and efficacy of the latest generation biodegradable polymer-coated ultrathin sirolimus-eluting stent in the treatment of coronary artery disease in a European all-comer population with or without high bleeding risk: The Cruz HBR Registry.

The latest generation ultrathin Supraflex Cruz (Sahajanand Medical Technologies Limited, Surat, India) sirolimus-eluting stent (SES) has shown early healing properties and represents an attractive percutaneous coronary intervention (PCI) device in a high bleeding risk (HBR) population. The aim of this Cruz HBR registry was to assess safety and efficacy of the Supraflex Cruz SES in a large cohort of all-comer patients, of whom about one third were patients at HBR. Patients undergoing PCI were enrolled in this prospective, multi-centre, open label registry and stratified into non-HBR and HBR groups. The primary endpoint was a device-oriented composite endpoint (DOCE), a composite of cardiovascular death, myocardial infarction not clearly attributable to a non-target vessel and clinically driven target lesion revascularization within 12 months after PCI. The predefined aims were to show non-inferiority of the non-HBR group to the Supraflex arm of the TALENT Trial, and of the HBR group to polymer-free biolimus-coated stent arm of LEADERS FREE Trial. A total of 1203 patients were enrolled across 26 European centers, including a significant proportion (38.7%; N.=466) of HBR patients. A total of 1745 lesions were treated in 1203 patients and 2235 stents were implanted. The DOCE occurred within the total cohort in 5.8% of patients with a significant difference between HBR patients and non-HBR patients (8.1% vs. 4.4%; P<0.001). All-cause mortality at 12 months was significantly (P<0.0001) different among HBR (9.0%) and non-HBR patients (1.7%), respectively. At 12 months, the overall incidence of definite and probable stent thrombosis was 1.0%. Major bleeding occurred in 5.9% patients of the HBR group. These results met the non-inferiority criteria with respect to the TALENT trial for the non-HBR group (P<0.0001), and the LEADERS FREE trial for the HBR group (P<0.0001). The Cruz HBR registry confirms that PCI with the Supraflex Cruz SES is associated with a favorable clinical outcome in an all-comer population, including complex patients with HBR.

Bioabsorbable ureteral stents: current state-of-the-art

Ureteral stenting is one of the main methods for draining the upper urinary tract. The main drawbacks associated with the use of ureteral stents include high treatment costs, stent-associated symptoms, "forgotten" ureteral stents, encrustation, and polymer recycling after stent removal. Biodegradable ureteral stents may be solution for mentioned problems, offering several advantages: (1) avoidance of stent removal, reducing invasion procedures and health costs; (2) prevention of "forgotten" stents; (3) improvement of quality of life; (4) reduction in carbon footprint. This article presents a literature review of the recent developments in biodegradable stent technology.

Feasibility assessment of polyvinyl alcohol-based bioresorbable cardiovascular stents manufactured via solvent-cast direct writing extrusion

BackgroundBioresorbable stents represent a promising approach in cardiovascular interventions compared to drug-eluting stents. Additive manufacturing, particularly ink deposition, offers customization and versatility. This study delves into the potential of solvent cast direct-write 3D printing to fabricate cardiovascular stents using environmentally friendly solvents. MethodologyPolyvinyl alcohol, a biocompatible synthetic polymer that dissolves in water, was investigated as a suitable material for stent fabrication. The polymer was deposited on a rotating mandrel and subsequently crosslinked to establish a pseudostable state. Test specimens and stents were fabricated for characterization of both the material and stent dynamics. ResultsThis outcome is potentially suitable for deployment in the human body environment and adaptable to various biomedical applications, such as drug delivery patches or implants. The research optimized the fabrication of various stent geometries using polyvinyl alcohol and evaluated the kinetics of the working environment of these stents. Specifically, the 8-cell diamond stent showed remarkable characteristics, such as a high overexpansion of more than 0.5 mm, a compression force of 0.02 N and an elastic recovery of 88.85 %, with a strut thickness of 50.25 μm. Additionally, the study discusses the possibility of sterilizing polyvinyl alcohol with different methods, ethanol and autoclave were selected. ConclusionsThe results indicate that autoclaving leads to an increase in crystallinity. This yields a decrease in water absorption and an increase in mechanical properties. These results suggest that polyvinyl alcohol-based stents fabricated by solvent-cast direct writing are potential candidates for bioresorbable stent design.