Permanent Stents Research Articles

Asymptomatic Intracerebral Hemorrhage May Worsen Clinical Outcomes in Acute Ischemic Stroke Patients Undergoing Thrombectomy

Background: Asymptomatic intracerebral hemorrhage (AICH) is a common phenomenon in patients with acute ischemic stroke (AIS) who were treated with endovascular thrombectomy (ET). This study aimed to evaluate the clinical effects of AICH and its risk factors in this patient population. Methods: This observational study was based on a prospective registry study. AIS patients with large-vessel occlusion in the anterior circulation and treated with ET were recruited. During thrombectomy procedures, intra-arterial infusion of thrombolytics or antiplatelet and permanent stenting were used as remedial therapies. The primary outcome was the overall distribution of modified Rankin scale (mRS) 90 days after ET. Results: This study included 102 patients (61.1 ± 12.7 years old), in whom 39 patients (38.2%) experienced AICH. At 90-day follow-up, the median mRS was 2 (interquartile range [IQR] 0-3) for patients without AICH and 4 (IQR 2-6) for those with AICH (adjusted P = .005). Fourteen patients with AICH and 7 patients without AICH died, which was significantly different (35.9% versus 11.1%, adjusted P = .015). Thirty-nine patients (61.9%) without AICH and 14 patients (35.9%) with AICH achieved functional independence at 3-month follow-up (adjusted P = .117). The length of intensive care unit staying was 5 days (IQR 2-10) in patients without AICH and 8 days (IQR 3-19) in those with AICH (adjusted P = .840). In multivariate analysis, lower Alberta Stroke Program Early CT Score (ASPECTS) (adjusted P = .003) and adjunctively intra-arterial thrombolysis (adjusted P = .016) were independently associated with AICH. Conclusions: In AIS patients treated with ET AICH appears to be associated with worse functional outcomes and high mortality. Lower ASPECTS and adjectively intra-arterial thrombolysis were independent risk factors of AICH.

Need for rescue treatment and its implication: stent retriever versus contact aspiration thrombectomy

BackgroudThe need for rescue treatment (RT) may differ depending on first-line modality (stent retriever (SR) or contact aspiration (CA)) in endovascular thrombectomy (EVT). We aimed to investigate whether the type...

In vitro degradation and biocompatibility evaluation of typical biodegradable metals (Mg/Zn/Fe) for the application of tracheobronchial stenosis

Tracheobronchial obstruction in children due to benign stenosis or tracheobronchomalacia still remains a challenging matter of concern. Currently, there is 10%–20% complication rate in clinical treatment. The non-biodegradable property of silicone stents and nickel-titanium memory alloy stents take the primary responsibility for drawbacks including stimulating local granulation tissue proliferation, displacement, and stent-related infections. Permanent tracheobronchial stent will be a persistent foreign object for a long time, causing excessive secretion of tracheal mucosa, ulceration and even perforation, which is particularly unsuitable for young children with persistent tracheal growth. In this study, the degradation and biocompatibility performance of three typical biodegradable metals were investigated as potential tracheobronchial stent materials. The results exhibited that these materials showed different degradation behaviors in the simulating respiratory fluid environment compared with SBF. Except for pure iron group, high purity magnesium and zinc showed favorable cell adhesion and proliferation in three culture methodologies (direct culture, indirect culture and extraction culture). The proper corrosion rate and good biocompatibility indicated that high purity magnesium and zinc may be good candidates as tracheobronchial stent materials.

Solitaire Stent Permanent Implantation as an Effective Rescue Treatment for Emergency Large Artery Occlusion

In this study, we present our experiences on the feasibility of rescue permanent Solitaire stent placement for failed mechanical thrombectomy (MT) and our protocol to avoid ineffective stent placement. We retrospectively evaluated the data for consecutive patients admitted into the Second Affiliated Hospital of Wenzhou Medical University and 2 collaboration hospitals from August 2014 to May 2018 for emergency large artery occlusion. The baseline clinical characteristics and radiologic assessment, interventional data, clinical outcome, and angiographic follow-up data were assessed. Notably, we introduced our protocol for antegrade flow assessment before Solitaire stent detachment to ensure an effective stent implantation. Thirty-nine patients (mean age, 68.1 years, mean preprocedural National Institute of Health Scale Score, 22.1) were included, in which 34 patients had anterior circulation large artery occlusion and 5 patients had posterior circulation large artery occlusion. The MT attempts ranged from 1-5 (3.6 on average). The mean onset-to-puncture time was 4.8 hours (ranging from 2.1-7.8 hours) and the mean procedure time was 87.4 minutes (ranging from 32-124 minutes). Modified thrombolysis in cerebral infarction 2b-3 reperfusions were noted in all cases. The immediate, average postprocedure stenosis rate was 25.3%, and the average stenosis rate at the 3-month angiographic follow-up was 34.7% (data from 15 patients). Three patients died. Nineteen (48.7%) patients had good outcome (modified Rankin Scale, mRS ≤2) at the 3-month follow-up. Permanent Solitaire stent placement might be a feasible therapy for patients with MT-failed emergency large artery occlusion. For a successful revascularization, careful antegrade flow assessment before stent detachment is critical.

A retrospective, multicenter analysis of incidents associated with Axios™ lumen-apposing stents.

there is controversy with regard to the risks associated with lumen-apposing metal stents (LAMSs), with significant variations between available reports. to describe the types and proportions of complications that arise during the permanence time and removal of Axios™ LAMS. Furthermore, the relationship between patency time, therapeutic target and the presence of complications was also described. a retrospective, multicenter case series study was performed of all patients with an implanted LAMS to access extra-luminal structures during 2017. Only technically successful cases were recorded. a total of 179 patients from seven sites (range, 4-68 cases/site) were included in the study, with a mean age of 64.3 years (SD: 15.8; range: 24.6-98.8 years) and 122 (68.2%) were male. Most common indications included encapsulated necrosis (58, 32.4%), pseudocysts (31, 17.3%) and gallbladder drains (26, 14.5%). Complications during LAMS stay were reported in 19 patients (10.9%); stent lumen or gastroduodenal obstruction (8, 4.5%) and bleeding (7, 3.9%) were the most common. LAMS were not removed in 86 (48%) patients due to the following reasons: a permanent stent was used (46, 53.5%), loss to follow-up (18, 20.9%), patient demise (16, 18.6%) and stent migration (6, 7%). Five (5.4%) complications were reported during stent removal, which were three bleeds and two perforations. No association was found between stent duration and complications (p = 0.67). complications secondary to LAMS insertion are uncommon but may be serious. This study found no association between complications and stent duration.

Minimum Quantity Lubrication in Fibre Laser Processing For Permanent Stents Manufacturing

Despite Bioresorbable Stents (BRS) are the main research line nowadays, permanent stent, both Bare Metal Stents (BMS) as Drug Eluting Stents (DES) will always be useful in some patient-specific cases. To produce permanent stents the current industrial technique is the Laser Micro Cutting. However, this technology produces some thermal damages which raise the manufacture cost. Most of the works done in the last decades have tried to reduce this damages adding traditional cooling techniques. This work aims to study the fibre laser micro cutting process of SS316 tubes assisted by Minimum Quantity Lubrication (MQL). The influence of pulse power, cutting speed, and quantity of coolant upon cutting quality was studied. Cut samples were analyzed by Optical Microscopy with Nikon SMZ – 745T attached to digital camera CT3 ProgRes and a Scanning Electron Microscopy Quanta 3D FEG. MQL has demonstrated an average reduction of the dross deposition area (43.3 %), recast layer (37.8 %), kerf width (7.1 %) and heat affected zone (7.46 %) becoming in an effective, economic, and ecologic technique to reduce the thermal damages in laser manufacturing process.

Mechanical Analysis of a Novel Biodegradable Zinc Alloy Stent Based on Degradation Model

Biodegradable stents which can avoid risks caused by incompatibility between artery and permanent stents are attracting much interests. However, biodegradable stents have not been extensively applied in clinical therapy because of their insufficient scaffold performance as a result of poor Young’s Modulus of biodegradable materials and weaken structures in degradation process. In this study, a patented stent and a common stent were simulated to degrade in a 40% stenotic vesel based on a corrosion model involving uniform corrosion and stress corrosion. In the degradation process, the scaffold performance of the two stents and their functionality on reshaping diseased vessels are analyzed. The results showed that radial recoiling ratio and mass loss ratio of the common stent is 22.6% and 14.1%, respectively. In comparison, radial recoiling ratio and mass loss ratio of the common stent are definitely lower than those of the common stent, at the value of 7.19% and 3.1%. It is indicated that the patented stent still has a stronger scaffold performance compared with the common stent. Besides, with positive influence of the patented stent on stenotic vessel, a larger and flatter lumen was observed in the plaque deployed with the patented stent. It implies that mechanical performance of biodegradable stents and their functionality highly depend on their geometries. Owing to improved mechanical performance induced by structural innovation, the novel biodegradable zinc alloy stent is promised to be an alternative choice in intervention surgeries.

Comparative preclinical evaluation of a polymer-free sirolimus-eluting stent in porcine coronary arteries.

Background:Polymer-free drug-eluting stents (DES) without permanent-polymer coating may be associated with rapid vessel healing, providing a rationale to reduce dual-antiplatelet therapy (DAPT). The aim of the current study was to compare vessel healing of a polymer-free sirolimus-eluting stent (PF-SES), its bare metal stent (BMS) analogue to a permanent polymer-based sirolimus-eluting stent (SES) with proven effectiveness in porcine coronary arteries.Material and methods:An ultrathin-strut cobalt–chromium PF-SES, its BMS analogue and an SES with a permanent polymer were used to study vessel healing and their antistenotic potential. Stents were implanted in porcine coronary arteries for histopathologic analysis at 7, 28 and 180 days.In an additional in vitro study, the thrombogenicity of PF-SES was compared with a fluoropolymer-coated everolimus-eluting stent (EES) which demonstrated low stent thrombosis rates in numerous studies.Results:In the animal study, neointimal growth and injury scores were minimal and inflammation scores were low in the neointima and adventitia in all study groups. After 28 days, neointimal area was lowest in PF-SES when compared with SES and BMS (1.48 ± 0.55 mm² versus 2.43 ± 0.69 mm² versus 1.90 ± 0.85 mm², respectively, p < 0.05) and endothelialization of luminal surfaces was nearly complete in all groups, though SES show the least coverage with occasional adherent luminal inflammatory cells (p > 0.05). At 180 days, neointimal area and thickness were most pronounced in SES (p < 0.05) and comparable with BMS implantations, which were characterized by nearly completed vessel healing. PF-SES and BMS had complete endothelialization, absence of fibrin and sustained low inflammatory reaction when compared with the permanent polymer-based SES (inflammation score: PF-SES 0.41 ± 0.74 versus SES 2.52 ± 1.72 versus BMS 0.30 ± 0.65, respectively, p < 0.05 BMS versus SES). Granuloma formation and fibrin accumulation were most pronounced in SES but did not reach statistical significance, p > 0.05). In the in vitro thrombogenicity study, the PF-SES confirmed comparable antithrombogenic properties with regard to the parameters fibrin and platelet binding, and platelet aggregation when compared with the EES.Conclusions:As compared with BMS, the ultrathin-strut cobalt–chromium PF-SES showed similar endothelialization at 28 days and comparable healing characteristics at 180 days efficacious inhibition of neointimal proliferation in porcine coronary arteries with low inflammation responses and a BMS-like endothelialization at 180 days. In addition, in an in vitro model, the PF-SES also confirmed low thrombogenicity as compared with the EES.

The Ultimaster Bioresobable Polymer Sirolimus-eluting Coronary Stent. Real World Data from the Largest Australian Single-site Database

The Ultimaster stent is bioresorbable polymer sirolimus-eluting stent currently being investigated for abbreviated duration dual antiplatelet therapy in high risk bleeding patients [[1]Management of High Bleeding Risk Patients Post Bioresorbable Polymer Coated Stent Implantation With an Abbreviated Versus Prolonged DAPT Regimen (MASTER DAPT), Cardialysis et.al. European Cardiovascular Research Center. ClinicalTrials.gov Identifier: NCT03023020.Google Scholar]. We aim to review the real-world safety and performance data from Wollongong Hospital, the highest utiliser of Ultimaster stents in Australia. A retrospective analysis of 317 patients receiving a total of 536 stents from August 2017 to January 2019 was performed. Target lesion failure (TLF), a outcome of unsuccessful intervention, target vessel related myocardial infarction and cardiac death), was measured and patient specific endpoints of MACE (composite of all-cause death, myocardial infarction and stroke) and major bleeding were also measured. Outcomes were recorded until the time of writing. Of the 317 patients (mean age 67.6 ± 11.4 years and 70% male) 65.9%, 56.8% and 30.0% had hypertension, hyperlipidaemia and diabetes respectively and 59.9% were smokers. 89.3% of patients were initiated on aspirin/clopidogrel post-PCI with ticagrelor and prasugrel replacing clopidogrel in 4.7% and 5.4% respectively. 76% of stents were inserted via radial access. Average stent diameter and length was 2.95 ± 0.48mm and 21.89 ± 8.55 mm, respectively. Analysis revealed an incidence of 4.4% TLF and 8.2% MACE while the incidence of major bleeding was 3.4%. This is the first real-world study in Australia on the Ultimaster stent and results are comparable with pre-marketing randomised controlled trials [[2]Wohrle J. Markovic S. Rottbauer W. Muramatsu T. Kadota K. Vazquez-Gonzalez N. Odenstedt J. Serra A. Antoniucci D. Varenne O. Saito S. Wijns W. Bioresorbable polymer sirolimus-eluting coronary stent compared with permanent polymer everolimus-eluting coronary stent implantation for treatment of small vessel coronary artery disease: CENTURY II trial.EuroIntervention [Internet]. 2016; 12 (In: Ovid MEDLINE(R) [Internet].): e167-e174Google Scholar] proving translation of safety and efficacy into clinical application.

A Review based on Biodegradable and Bioabsorbable Stents for Coronary Artery Disease

In the treatment of atherosclerotic vascular disease, angioplasty is widely used and has made a significant progress in the recent years. Drug-eluting stents are effective as well as raising the concerns associated like restenosis. In order to solve the problem of In-stent Restenosis; biodegradable stents are modified in such a way to superfluous permanent stent. Targeted drug delivery has more powerful impact as compared to metallic stents with thin coating of drug. Numerous research groups have investigated biodegradable materials like corrosive metals, polycarbonates, polyesters & bacterial-derived polymers for developing stents. A biodegradable stent is assumed to be ideal if it can be accurately installed under the fluoroscopic regulation and detect the target lesion with a trivial endovascular torment. Likewise, the advantages of bio-absorbable polymeric stents are not correlated with late stent thrombosis and leave no stent behind, they are completely suitable for Magnetic Resonance Imaging (MRI) and Multi-Slice Computer Tomography (MSCT) imaging. This survey covers the distinctive stent line-ups and bio-absorbable stents and their potentials.

Balloons and Stents and Scaffolds: Preclinical Evaluation of Interventional Devices for Occlusive Arterial Disease.

Atherosclerosis places a significant burden on humankind; it is the leading cause of mortality globally, and for those living with atherosclerosis, it can significantly impact quality of life. Fortunately, treatment advances have effectively reduced the morbidity and mortality related to atherosclerosis, with one such modality being percutaneous intervention (PCI) to open occluded arteries. Over the 40-year history of PCI, preclinical models have played a critical role in demonstrating proof of concept, characterizing the in vivo behavior (pharmacokinetics, degradation) and providing a reasonable assurance of biologic safety of interventional devices before entering into clinical trials. Further, preclinical models may provide insight into the potential efficacy of these devices with the appropriate study design and end points. While several species have been used in the evaluation of interventional devices, the porcine model has been the principal model used in the evaluation of safety of devices for both coronary and endovascular treatments. This article reviews the fundamentals of permanent stents, transient scaffolds, and drug-coated balloons and the models, objectives, and methods used in their preclinical evaluation.

Results of stenting the left main lesions in patients with stable coronary artery disease using biodegradable polymer and permanent polymer stents

Background. Routine coronary angiography reveals about 4–10% cases of the left main lesions in patients with different forms of coronary artery disease. With the advance of stenting technologies, percutaneous coronary intervention in this type of lesions might be an alternative to coronary artery bypass grafting in some patients. Despite a significant technical progress and current generations of drug-eluting stents, the issue of optimal dual antiplatelet therapy (DAAT) duration to minimize hemorrhagic complications in the long-term period is still an open question. The problem is especially acute in the case of left main lesions. Aim. To evaluate clinical outcomes of unprotected left main stenting using Synergy stents (Boston Scientific) followed by 4-month DAAT and Xience Prime stents (Abbott Vascular) followed by 12-month DAAT.Methods. Fifty patients with stable coronary artery disease were randomized into two groups depending on the stent type (Synergy and Xience). The subjects were evaluated in 12 months after the stenting procedure.Results. 100 % success was achieved in the study. At 3-month check-up, the indicators of endothelialization, strut overlapping and late lumen bore did not statistically differ in the groups under study. During 12-month follow-up 2 cases of restenosis were recorded, one in each group, which required revascularization. The remaining cases of repeated revascularization were associated with de novo lesions. The overall major cardiac events rate was 4% in the Xience group and 8% in the Synergy group. In one case, myocardial infarction in the Synergy group was associated with the right coronary artery.Conclusion. While treating patients with left main lesions, the use of Synergy stents followed by 4-month DAAT has no lesser clinical efficacy and safety than the Xience stents followed by 12-month DAAT. Received 28 August 2018. Revised 8 October 2017. Accepted 8 November 2018. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest. Author contributionsConception and study design: R.U. Ibragimov, O.V. KrestyaninovData collection and analysis: R.U. Ibragimov, D.A. Khelimskiy, A.G. BadoyanStatistical analysis: R.U. Ibragimov, D.A. Khelimskiy, A.G. BadoyanDrafting the article: R.U. Ibragimov, D.A. Khelimskiy, A.G. BadoyanRevision of the article: R.U. Ibragimov, O.V. Krestyaninov, E.A. Pokushalov, A.B. RomanovFinal approval of the version to be published: R.U. Ibragimov, A.G. Badoyan, D.A. Khelimskiy, O.V. Krestyaninov, E.A. Pokushalov, A.B. Romanov ORCID IDE.A. Pokushalov, https://orcid.org/0000-0002-2560-5167

A systematic review and meta-analysis of observational evidence for the use of bailout self-expandable stents following failed anterior circulation stroke thrombectomy

BackgroundThe crucial role of thrombectomy in the management of emergent large vessel occlusive stroke is not disputed but there is a technical failure rate in a significant minority of patients...

Immune–inflammatory response after bioresorbable vascular scaffold implantation in patients with acute myocardial infarction with ST elevation in a long-term perspective

A higher rate of bioresorbable vascular scaffold (BVS) thrombosis has been observed after device implantation compared to implantation of permanent metallic stents in recently published studies. The mechanism of BVS thrombosis is currently under debate. To assess whether the immune-inflammatory response after BVS implantation is a potential trigger of BVS thrombosis. The PRAGUE-19 study was an academic study that enrolled consecutive patients with ST-segment elevation myocardial infarction (STEMI) with the intention to implant a BVS. A laboratory sub-study included 49 patients with an implanted BVS (of which 38 underwent the complete 2-year follow-up) and 52 patients having an implanted permanent metallic stent as the control group (of which 30 underwent the complete 2-year follow-up). Samples for inflammatory markers [high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α)] were taken before BVS or stent implantation, on days 1 and 2 after device implantation and at 1month and 2years for a clinical control. The primary combined clinical endpoint of the sub-study (death, reinfarction or target vessel revascularization) occurred in 4.08% of the BVS group and 7.69% of the control group (p = 0.442) during the 2-year follow-up period, with overall mortality of 2.04% in the BVS group and 1.92% in the control group (p = 0.966). Definite BVS thrombosis occurred in one patient in the subacute phase; there was no late or very late thrombosis. Two definite stent thromboses were observed in the control group: one inthe subacute phase and the other inthe late phase. Baseline inflammatory marker levels did not differ between the groups. Lower levels of IL-6 and hs-CRP were observed in the BVS group compared to the control group (12.02 ± 5.94 vs. 15.21 ± 5.33pg/ml; p < 0.01; 3952.9 ± 1704.75ng/ml vs. 4507.49 ± 1190.01ng/ml; p = 0.037, respectively) on days 1 and 2 (12.01 ± 6.31 vs. 13.85 ± 6.01pg/ml; p = 0.089; 4447.92 ± 1325.31ng/ml vs. 4637.03 ± 1290.99ng/ml; p = 0.255, respectively). No differences in IL-6 or hs-CRP were observed after 1month or 2years in the clinical control. Levels of TNF-α did not differ between the groups in the early period after BVS or metallic stent implantation, nor during follow-up. The immune-inflammatory response is lower during the early phase after BVS implantation compared to that after metallic stent implantation, but the responses did not differ in the long term.

Crimping-induced structural gradients explain the lasting strength of poly l-lactide bioresorbable vascular scaffolds during hydrolysis

Biodegradable polymers open the way to treatment of heart disease using transient implants (bioresorbable vascular scaffolds, BVSs) that overcome the most serious complication associated with permanent metal stents-late stent thrombosis. Here, we address the long-standing paradox that the clinically approved BVS maintains its radial strength even after 9 mo of hydrolysis, which induces a ∼40% decrease in the poly l-lactide molecular weight (Mn). X-ray microdiffraction evidence of nonuniform hydrolysis in the scaffold reveals that regions subjected to tensile stress during crimping develop a microstructure that provides strength and resists hydrolysis. These beneficial morphological changes occur where they are needed most-where stress is localized when a radial load is placed on the scaffold. We hypothesize that the observed decrease in Mn reflects the majority of the material, which is undeformed during crimping. Thus, the global measures of degradation may be decoupled from the localized, degradation-resistant regions that confer the ability to support the artery for the first several months after implantation.

TCT-230 FFR-Guided Angioplasty Using Paclitaxel-Coated Balloons Without Stents vs. Bioresorbable Scaffolds: a Randomized Clinical Trial in Stable Coronary Artery Disease

Elimination of a permanent metallic stent from standard PCI techniques is desirable, since mid- and long-term adverse reactions may be triggered by an intracoronary foreign body. Aim: To investigate two „metal-free PCI techniques using either drug-coated balloons (DCB) or bioresorbable scaffolds

Vascular response towards biodegradable sirolimus-eluting polymeric scaffolds in the porcine model

Abstract In this study, PLLA-based sirolimus-eluting polymer scaffolds and permanent bare-metal stents (316L) were implanted interventionally into both common carotid arteries (CCA) of 6 female pigs via the left common iliac artery (8F-sheath). The pigs were administered dual antiplatelet drugs peroral starting 3 days before the procedure until the end of the study. Stented CCA segments were explanted after 12 weeks, and processed for quantitative histomorphometry, and estimation of vascular inflammation and injury scores. SIR/polymer scaffolds showed a decreased residual lumen area and higher restenosis after 12 weeks (4.45 ± 2.23 mm² and 61.68 ± 22.39%) as compared to the 316L reference stent (16.53 ± 1.23 mm² and 6.65 ± 1.30%). After 12 weeks, inflammation score and vascular injury score were higher in the SIR/polymer group (1.90 ± 1.15 and 1.26 ± 0.87) compared to the 316L group (0.57 ± 0.37 and 0.83 ± 0.34).

Damage control of caval injuries in a porcine model using a retrievable Rescue stent

ObjectiveEarly hemorrhage control before the operating room is essential to reduce the significant mortality associated with traumatic injuries of the vena cava. Conventional approaches present logistical challenges on the battlefield or in the trauma bay. A retrievable stent graft would allow rapid hemorrhage control in the preoperative setting when endovascular expertise is not immediately available and without committing a patient to the limitations of current permanent stents. This study details a refined retrievable Rescue stent for percutaneous delivery that was examined in a porcine survival model of penetrating caval hemorrhage. MethodsA retrievable caval stent was reduced in delivery profile to a 9F sheath using finite element analysis. The final stent was constructed with a “petal and stem” design using nitinol wire followed by covering with polytetrafluoroethylene. Seven Yorkshire pigs (79-86 kg) underwent 22F injury of the infrarenal vena cava with intentional class II hemorrhage (1200 mL). Percutaneous deployment of the Rescue stent was used to temporize hemorrhage for 60 minutes, followed by resuscitation with cell saver blood and permanent caval repair. Hemorrhage control was documented with photography and angiography. Vital signs were recorded and laboratory values were measured out to 48 hours postoperatively. Data were examined with a repeated-measures analysis of variance. ResultsThe profile of the caval Rescue stent was successfully reduced from 16F to 9F while remaining within fracture and shape memory limits for nitinol. In addition, both rapid deployment and recapture were preserved. Following intentional hemorrhage after caval injury, animals revealed a significant drop in mean arterial pressure (average, 30 mm Hg), acidosis, and elevated lactate level compared with before injury. Compared with uncontrolled hemorrhage, which resulted in death in <9 minutes, the Rescue stent achieved hemorrhage control in <1 minute after venous access in all seven animals. All animals were successfully recovered after permanent repair. There was no significant change in levels of transaminases, bilirubin, creatinine, or hemoglobin at 48 hours compared with preinjury baseline. ConclusionsA retrievable Rescue stent achieved rapid percutaneous hemorrhage control after a significant traumatic injury of the vena cava and allowed successful recovery of all injured animals. Further development of this approach may have utility in preoperative damage control of caval injuries.

Surface fluorination of polylactide as a path to improve platelet associated hemocompatibility

Surface-induced thrombosis is still a significant clinical concern for many types of blood-contacting medical devices. In particular, protein adsorption and platelet adhesion are important events due to their ability to trigger the coagulation cascade and initiate thrombosis. Poly(lactic acid) (PLA) has been the predominant polymer used for making bioresorbable stents. Despite long-term advantages, these stents are associated with higher rates of early thrombosis compared with permanent metallic stents. To address this issue, we modified the surface of PLA with a perfluoro compound facilitated by surface activation using radio frequency (RF) plasma. Fluoropolymers have been extensively used in blood contacting materials, such as blood vessel replacements due to their reduced thrombogenicity and reduced platelet reactivity. The compositions of plasma-treated surfaces were determined by electron spectroscopy for chemical analysis (ESCA). Also, contact angle measurements, cell cytotoxicity and the degradation profile of the treated polymers are presented. Finally, relevant blood compatibility parameters, including plasma protein adsorption, platelet adhesion and morphology, were evaluated. We hypothesized that tight binding of adsorbed albumin by fluoropolymers enhances its potential for blood-contacting applications. Statement of SignificanceAlthough bioresorbable stents made from poly(lactic acid) (PLA) may have long-term clinical advantages, they have shown higher rates of early thrombosis as compared with permanent metallic stents. To improve the thromboresistance of PLA, we developed a novel method for surface fluorination of this polymer with a perfluoro compound. Fluoropolymers (e.g., expanded polytetrafluoroethylene) have long been used in blood-contacting applications due to their satisfactory clinical performance. This is the first report of PLA surface fluorination which might be applied to the fabrication of a new generation of fluorinated PLA stents with improved platelet interaction, tunable degradability and drug release capabilities. Also, we describe a general strategy for improving the platelet interactions with biomaterials based on albumin retention.

Evolution of the SYNERGY bioresorbable polymer metallic coronary stent.

The SYNERGY stent is composed of thin, platinum-chromium metal alloy struts and an ultrathin, bioabsorbable poly-DL-lactide-co-glycolide polymer limited to the abluminal strut surface which elutes everolimus prior to complete resorption within 3-4 months. SYNERGY was designed to reduce inflammation and facilitate stent healing compared with permanent polymer drug eluting stents. This review summarizes the preclinical and clinical development of SYNERGY, its integration into clinical practice and future directions.