Small Stents Research Articles

Effect of Retrievable Stent Size on Endovascular Treatment of Acute Ischemic Stroke: A Multicenter Study.

In clinical practice, stent diameter is one of the variable properties important for endovascular treatment. A consensus guideline for stent retriever size selection has yet to be established. The aim of this study was to investigate the effects of different diameters of Solitaire retrievers on outcomes. Of 628 patients enrolled from the Endovascular Treatment for Acute Anterior Circulation Ischemic Stroke Registry, 256 were treated with the Solitaire 4-mm device and 372, with the 6-mm device. We matched patients treated with the 2 stent sizes using propensity score analysis. The successful outcome was reperfusion as measured by the modified Thrombolysis in Cerebral Infarction score immediately postprocedure and the dichotomized modified Rankin Scale score at 90 days. Symptomatic intracerebral hemorrhage and in-hospital mortality were also recorded. After propensity score analysis, group outcomes did not differ. In addition, in patients with atherosclerosis-related occlusion, a higher reperfusion rate (P = .021) was observed in the Solitaire 4 group, as well as a shorter time interval (P = .002) and fewer passes (P = .025). Independent predictors of successful reperfusion in patients with atherosclerotic disease on logistic analysis were the small stent (OR, 3.217; 95% CI, 1.129-9.162; P = .029) and the propensity score acting as a covariate (OR, 52.84; 95% CI, 3.468-805.018; P = .004). We found no evidence of a differential effect of intra-arterial therapy based on the size of Solitaire retrievers. In patients with atherosclerotic disease, favorable reperfusion was associated with deployment of a small stent.

The use of small stents to delay surgical intervention in very young children with critical congenital heart disease

Introduction: Surgery in very young children with critical obstructive congenital heart disease has a high morbidity and mortality. The aim of this study was to determine whether the use of small stents is feasible and if it could delay surgery. Materials and methods: Nineteen children were included in a retrospective review spanning 7 years. Patients were included in circumstances where surgery needed to be delayed and the use of a small stent could alleviate the underlying obstruction. Results: All attempts at stenting were successful (100%). Indications were diverse and included: aortic obstruction (n=9), right ventricular outfl ow tract obstruction (n=3), systemic-to-pulmonary artery shunt occlusion (n=5), infradiaphragmatic pulmonary vein obstruction (n=1) and salvage of a discontinuous left pulmonary artery (n=1). Reasons patients were not fi t for surgical intervention included: low weight (n=4), poor general clinical condition (n=12), surgical technical diffi culty (n=2) and unavailability of a critical care bed (n=1). Median age and weight at procedure was 4.6 months (range: 0.1 - 18.3) and 4.5kg (range: 1.7 - 9.5), respectively. Pressure gradients and saturations showed signifi cant improvement post stenting. Periprocedural complications were few (n=3) and there were no fatalities. Last follow-up was at a median of 7.8 months (range: 0.1 -9.0) post initial procedure. Nine cases proceeded to corrective surgery. Surgery was delayed by a median 13.5 months (range: 0.3 - 69.0 months) and weight increased to a median of 10.3kg (p<0.001). Five cases demised at a median of 73 days (range: 1 - 422) post initial stent placement, most at home secondary to unknown causes. Four patients remain in follow-up. One patient was lost to follow-up. Conclusion: The placement of stents in small, ill children is feasible. It immediately relieves the obstruction and improves the general clinical condition. Surgery can be delayed for weeks or months, thus giving the opportunity for somatic growth.

Interaction of primary human trabecular meshwork cells with metal alloy candidates for microinvasive glaucoma surgery.

Microinvasive glaucoma surgery (MIGS) is a relatively new addition to the glaucoma treatment paradigm. Small metallic stents are inserted into the trabecular meshwork in order to increase aqueous humour drainage. MIGS procedures are rapidly being adopted owing to a more favourable side effect profile when compared with traditional surgery. Remarkably, this rapid rate of utilization has occurred without any published studies on the effect of metal alloys used in these stents on human trabecular meshwork cells (HTMCs). Therefore, this study aimed to determine the effect of candidate metal alloys for MIGS on HTMC morphology, viability and function. Human trabecular meshwork cells were cultured on the surfaces of titanium (polished and sandblasted), a titanium-nickel (nitinol) alloy and glass (as control substratum). Fluorescence imaging was used to assess cell morphology and spreading. A lactate dehydrogenase cytotoxicity assay, cell death detection ELISA, MTT cell viability assay, BrdU cell proliferation assay and fibronectin ELISA were also conducted. Cells cultured on sandblasted titanium exhibited significantly greater spreading than cells cultured on other substrata. In comparison, HTMCs cultured on nitinol displayed poor spreading. Significantly more cell death, by both necrosis and apoptosis, occurred on nitinol than on titanium and glass. Also, cell viability and proliferation were suppressed on nitinol compared with titanium or glass. Finally, HTMCs on both titanium and nitinol produced greater amounts of fibronectin than cells grown on glass. Substratum topography and metal alloy composition were found to impact morphology, viability and function of primary HTMC cultures.

Abstract 13847: Impact of the Unzipping Technique on Pulmonary Artery Structure and Growth

Introduction: With the unzipping technique, small diameter stents are implanted to relieve pulmonary artery (PA) stenosis, subsequently dilated, fractured and re-stented with large stents dilatable to adult PA diameters. The unzipping technique is utilized in clinical practice with undefined long term results. This study assessed the impact of unzipping on PA structure and growth. Methods: Twelve piglets with left PA (LPA) stenosis underwent the unzipping sequence at 6, 10 and 18 weeks of age and were compared to normal controls and controls with untreated LPA stenosis. 2D and 3D rotational angiography pre/post interventions and PA histology was performed on all animals. Results: Eleven of twelve animals completed the three catheterizations. One stent (4 mm implant diameter) could not be crossed at the second procedure. Following the interventions, the diameter of the unzipped LPA was similar to the proximal LPA of normal controls (14 mm ± 1.2 vs 14.7 mm ± 1, p = 0.19). The diameter of the distal LPA was larger in normal controls, compared to interventions and controls with untreated LPA stenosis (14.6 mm ± 0.9 vs 11.6 mm ± 1.9, vs 10 mm ± 1.2, p &lt; .01). Diameters of six 1 st order LPA branches were similar between normal controls and interventions, and larger than the branch diameters in the stenosis controls. Right PA (RPA) dimensions were larger in controls with untreated stenosis, compared to normal controls and interventions (17.8 mm ± 1.2 vs 16.2 mm ± .9 vs 16 ± 1.7 mm p&lt;0.05). RPA 1 st order branching diameters were similar for normal controls and interventions. RPA 1 st order branch diameters in stenosis controls were larger for 3 of 6 branches compared to normal controls and 1 of 6 compared to interventions. Histologically, the distal LPA displayed uniform fibrointimal proliferation and smooth muscle hypertrophy in pigs with both interventions and untreated stenosis. Focal RPA fibrointimal proliferation was noted in stenosis and intervention animals. Conclusion: PA growth distal to the unzipped segment is partially compromised, yet 1 st order branch diameters are normal and significantly larger, compared to untreated stenosis. Histological vascular abnormalities are noted bilaterally in stenosis animals which do not normalize following the unzipping technique.

TCT-565 Fate of irregular protrusion after second-generation drug-eluting stent implantation: Serial optical coherence tomography study

Previous optical coherence tomography (OCT) study reported that irregular protrusion (IP), defined as protrusion of material with an irregular surface into lumen between stent struts, and small minimal stent area (MSA) at post drug-eluting stent (DES) implantation were independent predictors of 1-

The Use and Outcomes of Small, Medium and Large Premounted Stents in Pediatric and Congenital Heart Disease.

We sought to describe the use and outcomes of small, medium and large premounted stents in patients with congenital heart disease, including incidence of and risk factors for re-intervention and development of in-stent stenosis. Premounted stents offer several advantages over traditional manually crimped bare-metal stents, especially in small patients. There are no data describing the medium-term effectiveness and outcomes of premounted stents in congenital heart disease. We performed a single-center retrospective review of all small, medium and large premounted stents implanted over an 8-year period. Premounted stents were implanted in 71 vessels within 59 patients with a 97% success rate. Regardless of implantation site, premounted stent implantation resulted in significant improvements in vessel size and pressure gradient (p<0.0001). Over a median follow-up duration of 3.1years [interquartile range (IQR) 1.3-5.2], 25 patients (43%) required re-intervention (18 catheter based, 3 surgical and 4 hybrid) at a median time of 1.4years (IQR 0.9-3.0) from implant. Factors associated with re-intervention included age ≤1.9years [hazard ratio (HR) 2.4, p=0.03], weight ≤11.5kg (HR 2.5, p=0.03) and bare-metal premounted stents compared to covered premounted stents (HR 4.2, p=0.001). In-stent stenosis was diagnosed in 42% of premounted stents which underwent follow-up angiography. No identified characteristics were associated with in-stent stenosis, including "oversizing" the premounted stent. Small, medium and large premounted stents are effective in treating vascular stenosis in congenital heart disease. Frequent follow-up is required, especially in smaller patients with expected somatic growth, and to evaluate forin-stent stenosiswhich occurs in nearly half of premounted stents.

Preventing Post-ERCP Pancreatitis: Update 2016.

Post-ERCP remains a major challenge, although significant progress has been made in predicting risk and methods of prevention. Facets of post-ERCP pancreatitis can be divided into the four "P's": they are patient-related factors, procedure-related factors, pancreatic stents, and pharmacoprophylaxis. New information about risk factors includes a description of IPMN as a patient-related risk, with smoking and chronic liver disease as protective factors. Procedure-related factors include one or more deep passages of a guidewire into the pancreatic duct as a salient risk, perhaps outweighing difficult cannulation or contrast injection, but one that can be mitigated by placement of a pancreatic stent. In addition, placement of transpapillary metallic stents has emerged as an independent risk for post-ERCP pancreatitis (PEP). Although there has been a rising wave of enthusiasm for rectal NSAIDs as a kind of panacea for prevention of post-ERCP pancreatitis, the newest data question their efficacy in unselected cohorts. Pancreatic stent placement remains the most proven and reliable method of preventing post-ERCP pancreatitis in both mixed- and high-risk ERCP. Success at placement of protective pancreatic stents is a paramount for safety and efficacy, and technical expertise at placing pancreatic stents widely among centers. The use of specialized techniques including very small caliber guidewires and stents is necessary to approach 100% success.

Application of combined-type Y-shaped covered metallic stents for the treatment of gastrotracheal fistulas and gastrobronchial fistulas

ObjectiveTo determine the safety and feasibility of combined-type integrated Y-shaped self-expanding covered metallic stents to treat gastrotracheal fistulas (GTFs) and gastrobronchial fistulas (GBFs). MethodsWe retrospectively reviewed the data of 10 patients with postoperative GTFs or GBFs. Depending on the size and location of the fistula and the airway diameter, we custom-designed 2 or 3 stents for each patient. The combined-type stents consisted of a large and a small Y-shaped stent. Under fluoroscopic guidance, the small stent was inserted into the distal part of the involved airway. Then, the large stent was placed at the trachea and carina. The large stent partly overlapped the main body of the small stent. ResultsAll stents were successfully inserted at the first attempt. Esophageal and airway radiography showed no contrast agent leakage, indicating that the fistula was fully sealed. After the procedure, the patients could resume eating without coughing, and their quality of life improved. Each patient was fully followed up. Six patients died at 3.2 to 8 months of tumors (4 patients), hemoptysis (1 patient), or pulmonary infection (1 patient). In 1 patient, the carinal fistula enlarged 4 months after stenting, and another small Y-shaped stent was inserted to seal the fistula. This patient and the remaining 3 patients are still alive. ConclusionsDeployment of the combined-type Y-shaped integrated self-expanding covered metallic stent proved to be an effective, safe, and minimally invasive procedure for complex GTFs and GBFs. Our patients tolerated the stents well and had good palliation of their symptoms.

Real world experience of GenXSync and trade; sirolimus eluting coronary stent system in patients with long coronary lesions: outcome of the GEL registry

Background: The study aimed to assess the immediate (procedural outcome) and long- term clinical (Cumulative hierarchical MACE up to 2 years) and angiographic outcomes (late lumen loss at 8 months) in the patients undergoing angioplasty with at least one 40 mm GenXSync™ SES. (Indian Study Regulatory ID CTRI/2014/07/004783). Methods: This single centre prospective study included 26 real-world coronary artery disease (CAD) patients with long and very long lesions (38 lesions, 48 stents). All patients were treated with one or more 40 mm GenxSync™ sirolimus eluting stent (SES). All the subjects were followed up for 2 years including angiographic follow-up at 8 months. Angiography data was evaluated and reported by an independent angiographic core-lab. Subset analyses were performed for all 40mm long stents and 40mm with small diameter stents. Results: The procedural success was observed in 94%. The acute gain was 2.25±0.53mm in stent and 2.09±0.71mm in segment despite of long and complex lesions including CTO. At 2 years, there was only 1 (3.84%) MACE (binary restenosis at 8 months) and stent thrombosis. At 8 months late lumen loss was in-segment 0.15±0.30mm and in-stent 0.14±0.17mm (p = 0.06). The 40mm stents subset, revealed acute gain of 2.21±0.58mm in-stent and 2.01±0.74mm in-segment. The late loss was 0.16± 0.31mm and 0.13±0.17mm in-stent and in-segment respectively. In 40mm stent with small diameter subset, the acute gain was 2.19±0.42mm in-stent and 1.69 ± 0.59mm in-segment and late lumen loss was 0.10±0.18mm in-segment and 0.13± 0.33mm in-stent. Conclusions: The results of real world long lesions PCI revealed efficacy, safety and procedural success observed with GenXSync™ stent comparable to other reported studies.

Impact of an advanced image-based monoenergetic reconstruction algorithm on coronary stent visualization using third generation dual-source dual-energy CT: a phantom study

To evaluate the impact of an advanced monoenergetic (ME) reconstruction algorithm on CT coronary stent imaging in a phantom model. Three stents with lumen diameters of 2.25, 3.0 and 3.5mm were examined with a third-generation dual-source dual-energy CT (DECT). Tube potential was set at 90/Sn150kV for DE and 70, 90 or 120kV for single-energy (SE) acquisitions and advanced modelled iterative reconstruction was used. Overall, 23 reconstructions were evaluated for each stent including three SE acquisitions and ten advanced and standard ME images with virtual photon energies from 40 to 130keV, respectively. In-stent luminal diameter was measured and compared to nominal lumen diameter to determine stent lumen visibility. Contrast-to-noise ratio was calculated. Advanced ME reconstructions substantially increased lumen visibility in comparison to SE for stents ≤3mm. 130keV images produced the best mean lumen visibility: 86% for the 2.25mm stent (82% for standard ME and 64% for SE) and 82% for the 3.0mm stent (77% for standard ME and 69% for SE). Mean DLP for SE 120kV and DE acquisitions were 114.4 ± 9.8 and 58.9 ± 2.2mGy × cm, respectively. DECT with advanced ME reconstructions improves the in-lumen visibility of small stents in comparison with standard ME and SE imaging. • An advanced image-based monoenergetic reconstruction algorithm improves lumen visualization in stents ≤3.0mm. • Application of high keV reconstructions significantly improves in-stent lumen visualization. • DECT acquisition resulted in49 % radiation dose reduction compared with 120kV SE.

The influence of porosity on the hemocompatibility of polyhedral oligomeric silsesquioxane poly (caprolactone-urea) urethane

BackgroundThe physio-chemical properties of blood contacting biomaterials play an important role in determining their hemocompatibility. It is shown in literature that surface roughness and porosity have significant effect on hemocompatibility. In this study, we use a biocompatible, low thrombogenic nanocomposite polymer called POSS-PCU to test this hypothesis: would porosity compromise the hemocompatibility of POSS-PCU. We compared the hemocompatibility of POSS-PCU films of various pore sizes with PTFE, which is a commercially available material used in most blood contacting devices. MethodsSterilized POSS-PCU films with different size pores were prepared as samples and porous PTFE film were selected as control. And all samples were subjected to SEM for topograpgy, mechanical test for characterization and hemocompatibility tests to evaluate contact activation, platelet adhesion and activation, as well as whole blood clotting response to the samples. ResultsWCA significantly increased with the pore size of POSS-PCU film, whereas both tensile stress and strain decreased significantly as the sizes of pores increased. However, when compared to PTFE film with same size pores, POSS-PCU films showed both higher tensile stress and strain. Pore size had little impact over POSS-PCU's surface chemistry groups as tested by FTIR analysis. Contact activation and platelet adhesion essay also showed no significant difference between different POSS-PCU samples. However, in whole blood reactions, POSS-PCU with pores size around 2–5μm showed higher BCI than plain films and those with pores size around 35–45μm. POSS-PCU showed lower thrombogencity and higher hemocompatibility comparing with porous PTFE on the aspects of platelet activation, adhesion and whole blood reaction. Summary and conclusionsPOSS-PCU polymer films as a biomaterial in chronic blood contacting implants show significant lower thrombogencity and higher hemocompatibility than porous PTFE film. It is desirable as a coating or covering material in small diameter stents for treating cardiovascular diseases, cerebral vascular diseases and peripheral arterial diseases.

Incidence and Clinical Significance of Poststent Optical Coherence Tomography Findings: One-Year Follow-Up Study From a Multicenter Registry.

Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown. A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel-related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm(2) in a drug-eluting stent or <5.6 mm(2) in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points (P=0.003 and P=0.012, respectively). Abnormal poststent OCT findings were frequent. Irregular protrusion and small minimal stent area were independent predictors of 1-year device-oriented clinical end points, which were primarily driven by target lesion revascularization.

Multistenting during balloon-assisted ERCP using small diameter plastic stents in patients with surgically altered upper gastrointestinal anatomy.

Multistenting during balloon-assisted ERCP using small diameter plastic stents in patients with surgically altered upper gastrointestinal anatomy.

Current and Novel Imaging Techniques in Coronary CT.

Multidetector coronary computed tomography (CT), which is widely performed to assess coronary artery disease noninvasively and accurately, provides excellent image quality. Use of electrocardiography (ECG)-controlled tube current modulation and low tube voltage can reduce patient exposure to nephrotoxic contrast media and carcinogenic radiation when using standard coronary CT with a retrospective ECG-gated helical scan. Various imaging techniques are expected to overcome the limitations of standard coronary CT, which also include insufficient spatial and temporal resolution, beam-hardening artifacts, limited coronary plaque characterization, and an inability to allow functional assessment of coronary stenosis. Use of a step-and-shoot scan, iterative reconstruction, and a high-pitch dual-source helical scan can further reduce radiation dose. Dual-energy CT can improve contrast medium enhancement and reasonably reduce the contrast dose when combined with noise reduction with the use of iterative reconstruction. High-definition CT can improve spatial resolution and diagnostic evaluation of small or peripheral coronary vessels and coronary stents. Dual-source CT and a motion correction algorithm can improve temporal resolution and reduce coronary motion artifacts. Whole-heart coverage with 320-detector CT and an intelligent boundary registration algorithm can eliminate stair-step artifacts. By decreasing beam hardening and enabling material decomposition, dual-energy CT is expected to remove or reduce the depiction of coronary calcification to improve intraluminal evaluation of calcified vessels and to provide detailed analysis of coronary plaque components and accurate qualitative and quantitative assessment of myocardial perfusion. Fractional flow reserve derived from coronary CT is a state-of-the-art noninvasive technique for accurately identifying myocardial ischemia beyond coronary CT. Understanding these techniques is important to enhance the value of coronary CT for assessment of coronary artery disease.

Feasibility of Stent Fracture and Expansion in the Palliation of Branch Pulmonary Artery Stenosis

Branch pulmonary artery stenosis (BPAS) is a common consequence of the repair of congenital heart disease in pediatric patients. Although a small stent may be placed to relieve the BPAS, this intervention is temporary as these patients will eventually outgrow the stent. The purpose of our study was to investigate the feasibility of a proposed method of catheter‐based palliation of BPAS with 1) placement of a small stainless steel stent followed by 2) repeat catheterizations with sequential dilation and eventual fracturing of the stent and 3) restenting of the BPAS with a larger, expandable stent. We first compared the bench‐top fracture pattern of the 5mm Paramount Mini GPS stent with the in‐vivo fracture pattern in a piglet model of BPAS in which a 4 mm Gortex band was placed around the left pulmonary artery at 3 weeks of age. The 5 mm stent fractured on its horizontal axis at 12 mm and 12 ATM and the vertical axis at 14 mm and 16 ATM. In‐vivo, a 7 mm Paramount stent was placed two weeks post‐surgical creation of the BPAS and expansion was performed at 7 and 11 weeks (73kg). This stent also fractured on it horizontal axis after dilation to 12 mm diameter but was unable to be fractured on the vertical axis despite high pressure balloon dilation to 16 mm and 20 ATM. The stent substantially for‐shortened without vertical fracture, documented with fluoroscopy and necropsy. In subsequent studies to be presented here, we will examine the impact of restenting and subsequent stent expansion on vascular growth and right heart function.

CT Evaluation of Small-Diameter Coronary Artery Stents: Effect of an Integrated Circuit Detector with Iterative Reconstruction.

To use suitable objective methods of analysis to assess the influence of the combination of an integrated-circuit computed tomographic (CT) detector and iterative reconstruction (IR) algorithms on the visualization of small (≤3-mm) coronary artery stents. By using a moving heart phantom, 18 data sets obtained from three coronary artery stents with small diameters were investigated. A second-generation dual-source CT system equipped with an integrated-circuit detector was used. Images were reconstructed with filtered back-projection (FBP) and IR at a section thickness of 0.75 mm (FBP75 and IR75, respectively) and IR at a section thickness of 0.50 mm (IR50). Multirow intensity profiles in Hounsfield units were modeled by using a sum-of-Gaussians fit to analyze in-plane image characteristics. Out-of-plane image characteristics were analyzed with z upslope of multicolumn intensity profiles in Hounsfield units. Statistical analysis was conducted with one-way analysis of variance and the Student t test. Independent of stent diameter and heart rate, IR75 resulted in significantly increased xy sharpness, signal-to-noise ratio, and contrast-to-noise ratio, as well as decreased blurring and noise compared with FBP75 (eg, 2.25-mm stent, 0 beats per minute; xy sharpness, 278.2 vs 252.3; signal-to-noise ratio, 46.6 vs 33.5; contrast-to-noise ratio, 26.0 vs 16.8; blurring, 1.4 vs 1.5; noise, 15.4 vs 21.2; all P < .001). In the z direction, the upslopes were substantially higher in the IR50 reconstructions (2.25-mm stent: IR50, 94.0; IR75, 53.1; and FBP75, 48.1; P < .001). The implementation of an integrated-circuit CT detector provides substantially sharper out-of-plane resolution of coronary artery stents at 0.5-mm section thickness, while the use of iterative image reconstruction mostly improves in-plane stent visualization.

0176: Intraoperative pulmonary artery stenting for management of pulmonary artery stenosis in children with congenital heart diseases: a single center 5-year experience

Patients with Congenital Heart Diseases (CHD) often suffer from severe pulmonary artery (PA) stenosis. Management of PA stenosis is challenging for surgeons. The purpose of this study was to assess the results of intraoperative pulmonary artery stenting, performed additionally to, or instead of, conventional surgical angioplasty. Between January 2008 and August 2013, 31 children with hypoplastic or stenosed PA, median age of 23 months (range 6 days to 15 years), and median weight of 11,8kg (range 2,8 to 63kg), underwent intraoperative placement of stents in PA. Patients had pulmonary atresia (15) tetralogy of Fallot (10) troncus arteriosus (4), and complex CHD (2). The aim of the concomitant surgical procedure was palliative surgery (10), complete repair (12), or improvement of right ventricular outflow tract after complete repair (9). A total of 42 balloon-expandable stents were deployed in left or right PA. Maximum balloon diameters ranged from 3 to 16mm (mean=9). Post-operative mortality was 9,6% (3 patients) and 2 patients did not have complete follow-up. Eighteen patients underwent angiographic control, at a mean follow-up of 15 months (± SD 10 months) after surgery. Mean PA diameter increased from 5,19 to 7,57mm (p<0,001). Eight patients did not have angiography to date because routine echocardiography follow-up showed patent pulmonary arteries, with low residual gradient. Two patients (7,6%) needed a reoperation for severe intra-stent stenosis. Nine patients (34,6%) had repeated dilatation, performed percutaneously or during further intervention to complete repair of their CHD. Intraoperative stenting of PA is an effective option to prevent recoil and external compression. However, smaller stents seem to be at higher risk of intra-stent proliferation.

Prospective, multi-center evaluation of a silicon carbide coated cobalt chromium bare metal stent for percutaneous coronary interventions: two-year results of the ENERGY Registry.

Novel bare metal stents with improved stent design may become a viable alternative to drug-eluting stents in certain patient groups, particularly, when long-term dual antiplatelet therapy should be avoided. The ENERGY registry aimed to assess the safety and benefits of a cobalt-chromium thin strut bare metal stent with a passive coating in a large series of patients under real-world conditions. This prospective registry recruited 1016 patients with 1074 lesions in 48 centers from April to November 2010. The primary endpoint was the rate of major adverse cardiac events (MACEs), a composite of cardiac death, myocardial infarction and clinically driven target lesion revascularization. More than half of the lesions (61.0%) were type A/B1 lesions, mean lesion length was 14.5±6.5mm and mean reference vessel diameter 3.2±0.5mm. MACE rates at 6, 12 and 24months were 4.9%, 8.1% and 9.4%, target lesion revascularization rates 2.8%, 4.9% and 5.4% and definite stent thrombosis rates 0.5%, 0.6% and 0.6%. Subgroups showed significant differences in baseline and procedural characteristics which did not translate into significantly different clinical outcomes. Specifically, MACE rates at 24months were 13.5% in diabetics, 8.6% in small stents and 9.6% in acute coronary syndrome patients. The population of ENERGY reflects real-world conditions with bare metal stents being mainly used in simple lesions. In this setting, percutaneous coronary intervention using a cobalt-chromium thin strut bare metal stent with a passive coating showed very good results up to 24months. (ClinicalTrials.gov:NCT01056120) SUMMARY FOR ANNOTATED TABLE OF CONTENTS: The ENERGY international registry evaluated the safety and benefits of a cobalt-chromium thin strut bare metal stent with passive coating in 1016 patients under real-world conditions until 2years. Results were encouraging with a low composite rate of cardiac death, myocardial infarction and clinically driven target lesion revascularization, even in the pre-defined high risk groups of diabetes, stents ≤2.75mm and acute coronary syndrome.

Coronary stent occlusion: reverse attenuation gradient sign observed at computed tomography angiography improves diagnostic performance.

To evaluate the incidence and diagnostic performance of reverse attenuation gradient (RAG) sign in patients with coronary stent occlusion. We retrospectively included patients with suspected restenosis who underwent both coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA) within 2 weeks. Stent occlusion at CCTA was defined as (1) complete contrast filling defect of large calibre stents (at least 3 mm), or (2) presence of RAG sign in patients with small calibre stents (less than 3 mm) or (3) presence of RAG sign in patients with non-diagnostic image quality of stents. The diagnostic performance of RAG sign was further assessed by comparison to ICA results. A total of 162 patients with 231 implanted stents were included. ICA confirmed stent occlusion in 59 patients (99 stents). RAG sign was present in 59.3% (35/59) of all stent occlusions. As shown by patient-based analysis, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of our diagnostic criteria for detection of stent occlusion were 79.7% (47/59), 100% (103/103), 100% (47/47) and 89.6% (103/115) respectively. Superior diagnostic performance was confirmed by receiver operating characteristic (ROC) analysis with an area under the curve of 0.898. RAG sign observed at CCTA in patients with coronary stenting represents reverse collateral flow distal to stents and is highly specific to indicate stent occlusion. • RAG sign in patients with previous stents represents retrograde collateral flow. • RAG sign in patients with previous stents indicates stent occlusion. • RAG sign improves detection of stent occlusion in small calibre stents.

Auxetic polyurethane stents and stent-grafts for the palliative treatment of squamous cell carcinomas of the proximal and mid oesophagus: A novel fabrication route

Squamous cell carcinoma is usually cancer of the upper oesophagus and is very aggressive cancer. The cancer of the cervical oesophagus causes a serious complication called dysphagia, which is difficulty in eating or swallowing and which is indicative of incurability. Oesophageal stents have been used as a relatively better palliative method for patients who are suffering from advanced stage squamous cell carcinomas of oesophagus and also for the effective relief of dysphagia. There are still problems in currently available self-expanding metals and plastic stents, which are associated with high rates of early and late complications. This research work is aimed to use Auxetic (rotating-squares) geometry for the production of a novel Auxetic oesophageal stents and stent-grafts relevant to the palliative treatment of squamous cell carcinomas of the proximal and mid oesophagus and also for the prevention of dysphagia. This study also endeavoured to manufacture a significantly small diameter Auxetic oesophageal stent and stent-graft. In order to easily deploy the Auxetic stent orally using a commercial balloon dilatational catheter, and hence it also obviates the need of an expensive dedicated delivery system. A novel manufacturing route was employed in this research to develop both Auxetic films and Auxetic oesophageal stents, which ranged from conventional subtractive techniques to new generative manufacturing methods. Polyurethane was selected as a material for the fabrication of Auxetic films and Auxetic oesophageal stents because of its good biocompatibility and non-toxicological properties. The developed Auxetic films were later used for the fabrication of seamed Auxetic oesophageal stents. The flexible polyurethane tubular grafts were also attached to the inner luminal side of the seamless Auxetic oesophageal stents, in order to prevent tumour in-growth.