Maglev-fabricated long and biodegradable stent for interventional treatment of peripheral vessels.

While chronic limb-threatening ischemia is a serious peripheral artery disease, the lack of an appropriate stent significantly limits the potential of interventional treatment. In spite of much progress in coronary stents, little is towards peripheral stents, which are expected to be both long and biodegradable and thus require a breakthrough in core techniques. Herein, we develop a long and biodegradable stent with a length of up to 118 mm based on a metal-polymer composite material. To achieve a well-prepared homogeneous coating on a long stent during ultrasonic spraying, a magnetic levitation is employed. In vivo degradation of the stent is investigated in rabbit abdominal aorta/iliac arteries, and its preclinical safety is evaluated in canine infrapopliteal arteries. First-in-man implantation of the stent is carried out in the below-the-knee artery. The 13 months' follow-ups demonstrate the feasibility of the long and biodegradable stent in clinical applications.

Vascular response following implantation of the third-generation drug-eluting resorbable coronary magnesium scaffold: an intravascular imaging analysis of the BIOMAG-I first-in-human study.

BACKGROUND: The 12-month outcomes of BIOMAG-I - the first-in-human study investigating the third-generation drug-eluting resorbable magnesium scaffold (DREAMS 3G) - showed promising results regarding clinical outcomes and late lumen loss. AIMS: The current study aimed to investigate vascular healing parameters assessed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS), focusing on strut visibility, vessel and scaffold areas, and neointimal growth patterns. METHODS: This is a BIOMAG-I substudy including patients with available serial OCT and IVUS data. We conducted a frame-based analysis of OCT findings in conjunction with IVUS-derived vessel and scaffold areas, evaluating the qualitative and quantitative aspects of vascular healing. RESULTS: Among the 116 patients enrolled in this trial, 56 patients treated with DREAMS 3G were included in the analysis. At 12 months, OCT imaging revealed that 99.0% of the struts were invisible, and no malapposed struts were depicted. While the vessel area showed no significant difference between the timepoints, the minimum lumen area significantly decreased from post-percutaneous coronary intervention to 6 months (6.88 mm2 to 4.75 mm2; p<0.0001), but no significant changes were observed between 6 and 12 months. Protruding neointimal tissue (PNT) - a unique neointimal presentation observed following resorbable magnesium scaffold implantation - was observed in 89.3% of the study patients at 12 months, and its area exhibited a 47.4% decrease from 6 to 12 months. CONCLUSIONS: This imaging substudy revealed that, at 12-month follow-up, virtually all struts of the DREAMS 3G scaffold became invisible, without evident malapposition. The vascular healing response to DREAMS 3G implantation also appeared favourable up to 12 months, which is indicated by advanced strut degradation and spontaneous regressing PNT between 6 and 12 months.

Comparison of biodegradable and metallic tension-band fixation for paediatric lateral condyle fracture of the elbow.

INTRODUCTION: In our retrospective study we compared the outcomes of paediatric lateral condyle fractures of the elbow fixed by bioabsorbable pins and tension-band sutures or by metallic tension-band with K-wires. MATERIALS AND METHODS: We reviewed the data of children operated on for lateral condyle fractures between 2010 and 2020. Patients were classified as follows: 1. fractures treated with metallic (KW group), 2. fractures treated with resorbable implants (BR group). We compared the distribution of age, sex and fracture type in each group. Operative times of the two techniques were also recorded and compared. We analysed the X-rays taken one year after the injury and measured the following parameters: presence of possible non-union, varus or valgus deviation, lateral spur formation. Patients whose follow-up period was less than one year were excluded. For categorical data, group comparisons were performed with Chi-square test or Fisher's exact test, depending on the sample size. The evaluation of discrete variables was performed with Mann-Whitney U test. RESULTS: 42 patients met the above criteria. We found 19 children in the Kirschner -wire + tansion band wire (KW) group and 23 in the Bioresorbable pin + tension band suture (BR) group. There were no significant differences between the study groups in terms of age, sex, left-right ratio, number of complications, operation time, number of Jacobs II and III cases or follow-up time. The operation time was on average 5 min longer in the bioresorbable group (K-wire mean = 62.1 min, Bioresorbable mean = 67 min), this difference, however, is not statistically significant (P = 0.177). In terms of minor and major complications, there was no statistically significant difference between the two groups. (P = 0.729). CONCLUSIONS: We did not notice any difference between the complication rates of the two methods, so the real advantage of the absorbable implant technique is that no second intervention is necessary. The benefits of using biodegradable implants in various osteosynthesis techniques need further confirmation by randomised trials.

Five-year outcomes of patients with diabetes mellitus treated with a sirolimus-eluting or a biolimus-eluting stents with biodegradable polymer. From the SORT OUT VII trial.

BACKGROUND: Diabetes mellitus is associated with higher risk of target lesion failure (TLF) after percutaneous coronary intervention. We studied the 5-year outcome in patients with diabetes mellitus treated with biodegradable polymer stents. METHODS: The SORT OUT VII was a randomised trial comparing the ultrathin sirolimus-eluting Orsiro stent (O-SES) and the biolimus-eluting Nobori stent (N-BES) in an all-comer setting. Patients (n = 2525) were randomised to receive O-SES (n = 1261, diabetes: n = 236) or N-BES (n = 1264, diabetes: n = 235). Endpoints were TLF (a composite of cardiac death, target-lesion myocardial infarction (MI), target lesion revascularization (TLR)), definite stent thrombosis and a patient related outcome (all-cause mortality, MI and revascularization) within 5 years. RESULTS: Patients with diabetes mellitus had higher TLF (20.6% vs 11.0%, (Rate ratio (RR) 1.85 95% confidence interval (CI): (1.42-2.40) and patient related outcome (42.0% vs 31.0%, RR 1.43 95% CI: (1.19-1.71)) compared to patients without diabetes. Among patients with diabetes mellitus, TLF after 5 years did not differ between O-SES and N-BES (21.2% vs 20.0%), RR 1.05 95% CI: (0.70-1.58), p = 0.81). Cardiac death, MI, TLR, and definite stent thrombosis did not differ between the groups. CONCLUSION: In patients with diabetes mellitus, 5-year outcomes were similar among patients treated with biodegradable polymer O-SES or N-BES. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01879358.

Treatment of a urethral stricture by image-guided placement of a custom-made absorbable stent in a standing, sedated horse.

A 10-year-old Irish Sport Horse gelding developed complications from a general anesthesia resulting in sling support and recurrent urinary catheterization. The horse subsequently presented signs of dysuria and pollakiuria, was diagnosed with sabulous cystitis, and developed a urethral stricture from the repeated catheterizations, which was confirmed on urethroscopy. Clinical signs persisted despite conservative management with topical corticosteroids and urethral bougienage with balloon dilators. An image-guided approach was used to treat the stricture with a custom-made polydioxanone stent placed in the urethra after which the horse was able to void normally and fully empty his bladder. Repeat urethroscopy and ultrasonography 6 months after the procedure showed the stent to have completely reabsorbed with urethra remaining patent. Nineten months after the procedure, the owner reports the horse remaining at his intended level of athletic performance with no dysuria.

Rationale and design of INFINITY-SWEDEHEART: A registry-based randomized clinical trial comparing clinical outcomes of the sirolimus-eluting DynamX bioadaptor to the zotarolimus-eluting Resolute Onyx stent.

BACKGROUND: Modern drug-eluting stents have seen significant improvements, yet still create a rigid cage within the coronary artery. There is a 2% to 4% annual incidence of target lesion failure (TLF) beyond 1 year, and half of the patients experience angina after 5 years. The DynamX bioadaptor is a sirolimus-eluting, thin (71 µm) cobalt-chromium platform with helical strands that unlock and separate after in vivo degradation of the bioresorbable polymer coating. This allows the vessel to return to normal physiological function and motion, along with compensatory adaptive remodeling, which may reduce the need for reintervention and alleviate angina following percutaneous coronary intervention (PCI). METHODS: The INFINITY-SWEDEHEART trial is a single-blind, registry-based randomized clinical trial (R-RCT) to evaluate the safety and effectiveness of the DynamX bioadaptor compared to the Resolute Onyx stent in the treatment of patients with ischemic heart disease with de novo native coronary artery lesions. The R-RCT framework allows for recruitment, randomization, and pragmatic data collection of baseline demographics, medications, and clinical outcomes using existing national clinical registries integrated with the trial database. The primary objective is to demonstrate noninferiority in terms of freedom from TLF (cardiovascular death, target vessel myocardial infarction, or ischemia-driven target lesion revascularization) at 1 year. Powered secondary endpoints will be tested sequentially for superiority from 6 months to the end of follow-up (5 years) for the following: 1) TLF in all subjects, 2) target vessel failure in all subjects, and 3) TLF in subjects with acute coronary syndrome (ACS). Subsequent superiority testing will be performed at a time determined depending on the number of events, ensuring sufficient statistical power. Change in angina-related symptoms, function and quality of life will be assessed using the Seattle Angina Questionnaire-short version. Predefined sub-groups will be analyzed. In total, 2400 patients have been randomized at 20 sites in Sweden. Available baseline characteristic reveal relatively old age (68 years) and a large proportion of ACS patients including 25% STEMI and 37% NSTEMI patients. SUMMARY: The INFINITY-SWEDEHEART study is designed to evaluate the long-term safety and efficacy of the DynamX bioadaptor compared to the Resolute Onyx stent in a general PCI patient population.

In Vitro Corrosion of Polyester-Coated Magnesium Alloy under pH-Static Conditions.

The resorption rate of bioresorbable implants requires tuning to match the desired field of application. The use of Mg as implant material is highly advantageous, as it provides sufficient mechanical strength combined with its biodegradability. Consequently, the implant vanishes after it has served its intended purpose, allowing the complete restoration of natural tissue and organ function. However, a biodegradable Mg implant requires a biodegradable coating to slow the rate of Mg corrosion, as a permanent coating would negate the benefits of using Mg as an implant material. Therefore, degradable polymers are the materials of choice, especially polyester-based coatings, such as PLLA, as they have been proven in clinical practice over the long term. Within this work, the degradation retarding effect of a physical barrier in form of four clinically relevant polyester-based coatings, poly-l-lactide (PLLA), poly-l-lactide-co-glycolide (PLGA), poly(l-lactide-co-PEG) triblock copolymer (PLLA-co-PEG), and polydioxanone (PDO), is investigated in vitro under pH-static conditions using CO2 gas to compensate pH changes due to Mg corrosion. Coating thicknesses of 7.5 to 8.3 µm were comparable to commercially available stent systems. Quantitative analysis of magnesium concentration in buffered test medium by a photometric assay allows real-time monitoring. Shielding effect of different polyesters through polymer coating and formation of a protective passivation layer beneath the polymer coating was observed and characterized using SEM and EDX techniques. Our finding was that even imperfect polymer layers provide a considerable protective effect, and the used in vitro setup matches reported in vivo observations regarding elemental composition of corrosion products.

Biocompatibility and osteogenic capacity of additively manufactured biodegradable porous WE43 scaffolds: An in vivo study in a canine model.

Magnesium is the most promising absorbable metallic implant material for bone regeneration and alloy WE43 is already FDA approved for cardiovascular applications. This study investigates the cyto- and biocompatibility of novel additively manufactured (AM) porous WE43 scaffolds as well as their osteogenic potential and degradation characteristics in an orthotopic canine bone defect model. The cytocompatibility was demonstrated using modified ISO 10993-conform extract-based indirect and direct assays, respectively. Additionally, degradation rates of WE43 scaffolds were quantified in vitro prior to absorption tests in vivo. Complete blood cell counts, blood biomarker analyses, blood trace element analyses as well as multi-organ histopathology demonstrated excellent biocompatibility of porous y WE43 scaffolds for bone defect repair. Micro-CT analyses further showed a relatively higher absorption rate during the initial four weeks upon implantation (i.e., 36 % ± 19 %) than between four and 12 weeks (41 % ± 14 %), respectively. Of note, the porous WE43 implants were surrounded by newly formed bony tissue as early as four weeks after implantation when unmineralized trabecular ingrowth was detected. After 12 weeks, a substantial amount of mineralized bone was detected inside and around the gradually disappearing implants. This first study on AM porous WE43 implants in canine bone defects demonstrates the potential of this alloy for in vivo applications in humans. Our data further underscore the need to control initial bulk absorption kinetics through surface modifications.

Crevice corrosion behavior of a biodegradable Zn-Mn-Mg alloy in simulated body fluid.

Crevice corrosion at the implantation sites cannot be neglected in clinical applications of biodegradable zinc alloys as implants. In this study, a crevice corrosion protocol was designed to investigate the crevice corrosion behavior of the Zn-0.45Mn-0.2Mg (ZMM42) alloy for the first time, by varying crevice thicknesses in simulated body fluid (SBF) through immersion and electrochemical analysis. The results indicated that the ZMM42 alloy was susceptible to crevice corrosion in the range from 0.03 mm to 0.2 mm. When the crevice thickness was 0.05 mm, the crevice corrosion of the specimen became more severe compared to other thicknesses.

Comparison of surgical outcomes between bioabsorbable and metal screw fixation for distal tibial physeal fracture in children and adolescent.

PURPOSE: This study aimed to compare the surgical outcomes between bioabsorbable and metal screw fixation for distal tibial physeal fracture in children and adolescents, radiographically and clinically. METHODS: This study included consecutive 67 children and adolescents who underwent open reduction and internal fixation using metal or bioabsorbable screws for the distal tibia physeal fracture. All patients underwent preoperative radiographs, three-dimensional computed tomography scans, and postoperative follow-up teleradiogram. Patients were divided into metal (N = 40) and bioabsorbable groups (N = 27). We compared the surgical outcomes between the two groups in terms of clinical and radiographic outcomes, length of hospital stays, and medical cost. RESULTS: Follow-up duration were significantly longer in the metal group than that in the bioabsorbable group. There was no significant difference in the incidence of growth arrest after surgery and the scores of the Oxford Ankle and Foot Questionnaire between the two groups. However, the total hospital stay was significantly longer in the metal group (5.2 ± 4.8 days) compared to the bioabsorbable group (2.6 ± 0.5 days). Medical costs were significantly higher in the bioabsorbable group than in the metal group with a difference of 397 US dollars. CONCLUSIONS: The use of bioabsorbable screws exhibited therapeutic effects equivalent to that of metal screws for pediatric distal tibia physeal fractures regarding clinical and radiological outcomes. Moreover, it had the advantage of avoiding the need for repeated general anesthesia and secondary operation for implant removal. Therefore, the use of bioabsorbable screws may be a favourable surgical option for treating pediatric fractures.

Corrosion behavior, antibacterial properties and in vitro and in vivo biocompatibility of biodegradable Zn-5Cu-xMg alloy for bone-implant applications.

Reasonable optimization of degradation rate, antibacterial performance and biocompatibility is crucial for the development of biodegradable zinc alloy medical implant devices with antibacterial properties. In this study, various amounts of Mg elements were incorporated into Zn5Cu alloy to modulate the degradation rate, antibacterial properties and biocompatibility. The effects of Mg contents on the microstructure, corrosion behavior, antibacterial properties and biocompatibility of Zn-5Cu-xMg alloy were extensively investigated. The results revealed that with an increase of Mg content, the amount of Mg2Zn11 phase increased and its galvanic effect with the Zn matrix was enhanced, which accelerated the corrosion process and led to higher corrosion rate and high degradation rate of the alloy. Additionally, there was an increased release of Mg2+ and Zn2+ ions from the alloy which imparted excellent resistance against Escherichia coli and Staphylococcus aureus bacteria and improved biocompatibility, subcutaneous antibacterial and immune microenvironment regulation properties. Zn-5Cu-2 Mg exhibited superior antibacterial ability, cell compatibility, proliferation effect, subcutaneous antibacterial and immune microenvironment regulation performances, which can work as a promising candidate of biodegradable antibacterial medical implants.

Bioabsorbable, subcutaneous naltrexone implants mitigate fentanyl-induced respiratory depression at 3 months-A pilot study in male canines.

The aim of this study is to determine if extended-release, bioabsorbable, subcutaneous naltrexone (NTX) implants can mitigate respiratory depression after an intravenous injection (IV) of fentanyl. Six different BIOabsorbable Polymeric Implant Naltrexone (BIOPIN) formulations, comprising combinations of Poly-d,l-Lactic Acid (PDLLA) and/or Polycaprolactone (PCL-1 or PCL-2), were used to create subcutaneous implants. Both placebo and naltrexone implants were implanted subcutaneously in male dogs. The active naltrexone implants consisted of two doses, 644 mg and 1288 mg. A challenge with IV fentanyl was performed in 33 male dogs at 97-100 days after implantation. Following the administration of a 30 µg/kg intravenous fentanyl dose, the placebo cohort manifested a swift and profound respiratory depression with a ~50% reduction in their pre-dose respiratory rate (RR). The BIOPIN NTX-implanted dogs were exposed to escalating doses of intravenous fentanyl (30 µg/kg, 60 µg/kg, 90 µg/kg, and 120 µg/kg). In contrast, the dogs implanted with the BIOPIN naltrexone implants tolerated doses up to 60 µg/kg without significant respiratory depression (<50%) but had severe respiratory depression with fentanyl doses of 90 µg/kg and especially at 120 µg/kg. Bioabsorbable, extended-release BIOPIN naltrexone implants are effective in mitigating fentanyl-induced respiratory depression in male canines at about 3 months after implantation. This technology may also have potential for mitigating fentanyl-induced respiratory depression in humans.

Long-Term Results of Bioresorbable Vascular Scaffolds in Patients With In-Stent Restenosis: The RIBS VI Study.

BACKGROUND: In patients with in-stent restenosis (ISR) bioresorbable vascular scaffolds (BVS) provide similar results to drug-coated balloons (DCBs) but are inferior to drug-eluting stents (DES) at 1 year. However, the long-term efficacy of BVS in these patients remains unknown. OBJECTIVES: This study sought to assess the long-term safety and efficacy of BVS in patients with ISR. METHODS: RIBS VI (Restenosis Intrastent: Bioresorbable Vascular Scaffolds Treatment; NCT02672878) and RIBS VI Scoring (Restenosis Intrastent: Bioresorbable Vascular Scaffolds Treatment With Scoring Balloon; NTC03069066) are prospective multicenter studies designed to evaluate the results of BVS in patients with ISR (N = 220). The inclusion and exclusion criteria were identical to those used in the RIBS IV (ISR of DES) (Restenosis Intra-stent of Drug-eluting Stents: Drug-eluting Balloon vs Everolimus-eluting Stent; NCT01239940) and RIBS V (ISR of bare-metal stents) (Restenosis Intra-stent of Bare Metal Stents: Paclitaxel-eluting Balloon vs Everolimus-eluting Stent; NCT01239953) randomized trials (including 249 ISR patients treated with DCBs and 249 ISR patients treated with DES). A prespecified comparison of the long-term results obtained with these treatment modalities (ie, DES, DCBs, and BVS) was performed. RESULTS: Clinical follow-up at 3 years was obtained in all (100%) 718 patients. The 3-year target lesion revascularization rate after BVS was 14.1% (vs 12.9% after DCBs [not significant], and 5.2% after DES [HR: 2.80; 95% CI: 1.47-5.36; P = 0.001]). In a landmark analysis (>1 year), the target lesion revascularization rate after BVS was higher than after DES (adjusted HR: 3.41; 95% CI: 1.15-10.08) and DCBs (adjusted HR: 3.33; 95% CI: 1.14-9.70). Very late vessel thrombosis was also more frequent with BVS (BVS: 1.8%, DCBs: 0.4%, DES: 0%; P = 0.03). CONCLUSIONS: In patients with ISR, late clinical results of DES are superior to those obtained with DCBs and BVS. Beyond the first year, DCBs are safer and more effective than BVS.

All-cause claims analysis of the LATERA absorbable nasal implant vs surgical repair in patients with nasal valve collapse.

AIMS: To compare all-cause claims associated with the LATERA Absorbable Nasal Implant and surgical repair of nasal vestibular stenosis in patients with nasal valve collapse. METHODS: This retrospective cohort study utilized data from STATinMED RWD Insights. A defined set of HCPCS, ICD-10-CM and CPT codes were used to identify patients with ≥1 claim for a LATERA procedure, and patients with ≥1 claim for surgical repair between June 1, 2015- March 31, 2023. Patients with continuous capture for at least 12 months before and at least 6 months after the index date were selected. The index date was defined as earliest date of encounter for a LATERA or surgical repair procedure. Inverse probability of treatment weighting (IPTW) was used to ensure balance between cohorts. Descriptive analyses were provided for all claims data using standard summary statistics. All-cause claims were assessed during the baseline, index date, and follow-up period. Chi-squared tests and independent sample t-tests were used to assess differences in cohorts for categorical and continuous variables, respectively. RESULTS: The study population included 5,032 LATERA patients and 26,553 surgical repair patients. During the baseline and follow-up periods, the matched cohorts exhibited similar all-cause claims. On the index date, LATERA patients incurred lower claims vs. surgical repair, likely due to LATERA's ability to be implanted in the physician office setting. LATERA patients and surgical repair patients mean (SD) total costs were $9,612 [$14,930] vs $11,846 [$17,037] (p ≤ 0.0001), respectively. CONCLUSIONS: Treatment with the LATERA Absorbable Nasal Implant is a potentially cost saving option for payers on the index date compared to traditional surgical repair in patients with nasal valve collapse due to the ability to be performed in the office. All-cause claims were similar in the baseline and follow-up periods. When performed with concomitant procedures, all-cause claims during follow-up were similar between groups.

Effectiveness and Biocompatibility Evaluation of a Novel Absorbable Bone Wax Used in Bone Tissue.

This study aims to determine the hemostatic effectivity and biocompatibility of a novel absorbable bone wax in comparison with a commercially available product. Eighteen small fat-tail sheep were used to simulate clinical surface bleeding of sternal injury. Hemostasis effectiveness, the degree of bone healing, micro-computed tomography, and histopathology were evaluated over a period after the application of the material to the surgically created wound. The absorbable bone wax used in the study stopped bleeding immediately and did not affect bone healing. The histopathological results also showed that there were no complications associated with the new material. The results showed that the new absorbable bone wax used in this study was effective and biocompatible.

Effect of hematoma on early degradation behavior of magnesium after implantation.

The corrosion of magnesium (Mg)-based bioabsorbable implanting devices is influenced by implantation environment which dynamically changes by biological response including wound healing. Understanding the corrosion mechanisms along the healing process is essential for the development of Mg-based devices. In this study, a hematoma model was created in a rat femur to analyze Mg corrosion with hematoma in the early stage of implantation. Pure Mg specimen (99.9%,ϕ1.2 × 6 mm) was implanted in rat femur under either hematoma or non-hematoma conditions. After a designated period of implantation, the specimens were collected and weighed. The insoluble salts formed on the specimen surfaces were analyzed using scanning electron microscopy, energy-dispersive x-ray spectroscopy, and Raman spectroscopy on days 1, 3, and 7. The results indicate that hematomas promote Mg corrosion and change the insoluble salt precipitation. The weight loss of the hematoma group (27.31 ± 5.91 µg mm-2) was significantly larger than that of the non-hematoma group (14.77 ± 3.28 µg mm-2) on day 7. In the non-hematoma group, carbonate and phosphate were detected even on day 1, but the only latter was detected on day 7. In the hematoma group, hydroxide was detected on day 1, followed by the formation of carbonate and phosphate on days 3 and 7. The obtained results suggest the hypoxic and acidic microenvironment in hematomas accelerates the Mg corrosion immediately after implantation, and the subsequent hematoma resorption process leads to the formation of phosphate and carbonate with organic molecules. This study revealed the risk of hematomas as an acceleration factor of the corrosion of Mg-based devices leading to the early implant failure. It is important to consider this risk in the design of Mg-based devices and to optimize surgical procedures controlling hemorrhage at implantation and reducing unexpected bleeding after surgery.