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In‐stent restenosis and thrombosis remain to be long‐term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH3/O2 (2:1 molar ratio) plasma post‐treatment (TMS + NH3/O2 nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2‐year aging time were characterized by wettability assessment and x‐ray photoelectron spectroscopy (XPS). It was found that TMS + NH3/O2 nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292–1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium (MTT) assay results revealed that, after 7‐day incubation, TMS + NH3/O2 nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co‐culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH3/O2 nanocoating surfaces was 1.5‐fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH3/O2 nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5‐fold on TMS + NH3/O2 nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH3/O2 nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH3/O2 nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH3/O2 nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications. [ABSTRACT FROM AUTHOR]

The main objective of this study was to solve a multi‐objective optimization on a representative coronary stent platform with the goal of finding new geometric designs with improved biomechanical performance. The following set of metrics, calculated via finite element models, was used to quantify stent performance: vessel injury, radial recoil, bending resistance, longitudinal resistance, radial strength and prolapse index. The multi‐objective optimization problem was solved with the aid of surrogate‐based algorithms; for comparison and validation purposes, four surrogate‐based multi‐objective optimization algorithms (EIhv‐EGO, Phv‐EGO, ParEGO and SMS‐EGO) with a limited sample budget were employed and their results compared. The quality of the non‐dominated solution sets outputted by each algorithm was assessed against four quality indicators: hypervolume, R2, epsilon and generational distance. Results showed that Phv‐EGO was the algorithm that exhibited the best performance in overall terms. Afterwards, the highest quality Pareto front was chosen for an in‐depth analysis of the optimization results. The amount of correlation and conflict was quantified for each pair of objective functions. Next, through cluster analysis, one was able to identify families of solutions with similar performance behavior and to discuss the nature of the existent trade‐offs between objectives, and the trends between design parameters and solutions in a biomechanical perspective. In the end, a constrained‐based design selection was performed with the goal of finding solutions in the Pareto front with equal or better performance in all objectives against a baseline design. [ABSTRACT FROM AUTHOR]

Abstract: High‐dimensional data provide many potential confounders that may bolster the plausibility of the ignorability assumption in causal inference problems. Propensity score methods are powerful causal inference tools, which are popular in health care research and are particularly useful for high‐dimensional data. Recent interest has surrounded a Bayesian treatment of propensity scores in order to flexibly model the treatment assignment mechanism and summarize posterior quantities while incorporating variance from the treatment model. We discuss methods for Bayesian propensity score analysis of binary treatments, focusing on modern methods for high‐dimensional Bayesian regression and the propagation of uncertainty. We introduce a novel and simple estimator for the average treatment effect that capitalizes on conjugacy of the beta and binomial distributions. Through simulations, we show the utility of horseshoe priors and Bayesian additive regression trees paired with our new estimator, while demonstrating the importance of including variance from the treatment regression model. An application to cardiac stent data with almost 500 confounders and 9000 patients illustrates approaches and facilitates comparison with existing alternatives. As measured by a falsifiability endpoint, we improved confounder adjustment compared with past observational research of the same problem. [ABSTRACT FROM AUTHOR]

In this work the development of an experimental protocol to perform the in situ gel-paving of coronary stent is presented. Biocompatible aqueous blends of Pluronic F127 and sodium alginates are used as potential drug dosage system for pharmacological in situ treatment of coronary in-stent restenosis. Pluronic F127/alginate aqueous blend has the unique characteristic to be liquid at room condition and to form gel at physiological temperature. The proposed protocol is based on the blend injection on stent wall previously implanted in a flexible silicon pipe mimicking the coronary artery. Injected blend is warmed up until human body temperature achieving a soft gel, then it is reticulated by copper bivalent ions to obtain an hard gel. To test the gel paving resistance to erosion phenomena when it is exposed to fluid flux (i.e. blood flux) a dedicated device, (the Simulated Artery Device, SAD), was built to simulate the human circulatory apparatus. The SAD is an hydraulic circuit in which a buffer solution (at pH 7.4) was fluxed by a peristaltic pump through the pipe hosting the covered stent. Erosion tests were performed monitoring, by gravimetric and spectrophotometric methods, the residual mass anchored to stent mesh after given times. The obtained results showed that the in situ gel-paving developed protocol was efficacious and reliable. The gel-paving was completely eroded in a time of the same order of magnitude of the physiological period required to restore the coronary lesion (subsequent to the atheroma removal) and of a pharmacological therapy to inhibit the in-stent-restenosis pathology. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1013-1022, 2016. [ABSTRACT FROM AUTHOR]

Background Parvovirus ( PV) B19 DNA is detected in endothelial cells and may cause endothelial dysfunction, which is involved in in-stent restenosis. We aimed at performing an exploratory analysis that evaluated if PVB19 DNA at the culprit coronary stenosis would be associated with an increased rate of major adverse cardiac events ( MACE) after coronary stenting. Materials and methods Consecutive patients undergoing stent implantation for stable or unstable coronary artery disease were enroled. Serology for PVB19 infection and presence of DNA for PVB19 on balloons used for predilatation were assessed in all patients. MACE rate, as a composite of cardiac death, myocardial infarction ( MI) or clinically driven target lesion revascularization ( TLR) was obtained at 24 month follow-up. Adjusted hazard ratio ( HR) with 95% confidence interval ( CI) was calculated for variables associated with MACE. Results One hundred and nine patients [age 66 ± 10, male sex 89 (82%)] were enroled. At 24-month follow-up, 18 patients experienced a MACE. Two patients (2%) experienced MI, while 16 patients (15%) experienced clinically driven TLR. At multiple Cox regression analysis, the presence of PVB19 DNA on the balloon and the use of bare-metal stents were independent predictors of MACE [ HR 3·30, 95% CI (1·12-10·08), P = 0·03 and HR 4·19, 95% CI (1·60-10·94), P = 0·003]. Conclusions PVB19 DNA detected on the balloon used for dilatation of coronary stenosis before stent implantation is associated with MACE rate at follow-up, mainly due to clinically driven TLR. The results of this exploratory analysis should be confirmed in a larger population. [ABSTRACT FROM AUTHOR]

This study seeks to improve the mechanical performance of stents by conducting reliability performance testing and finite element method ( FEM)-based simulations for coronary stents. Three commercially available stent designs and our own new design were tested to measure the factors affecting performance, specifically foreshortening, recoil, radial force, and flexibility. The stents used in the present experiments were 3 mm in working diameter and 18 mm of working length. The results of the experiments indicate that the foreshortening of stents A, B, C, and our new design, D, was equivalent to 2.25, 0.67, 0.46, and 0.41%, respectively. The recoil of stents A, B, C, and D was 6.00, 4.35, 3.50, and 4.36%, respectively. Parallel plate radial force measurements were A, 3.72 ± 0.28 N; B, 3.81 ± 0.32 N; C, 4.35 ± 0.18 N; and D, 4.02 ± 0.24 N. Radial forces determined by applying uniform pressure in the circumferential direction were A, 28.749 ± 0.81 N; B, 32.231 ± 1.80 N; C, 34.522 ± 3.06 N; and D, 42.183 ± 2.84 N. The maximum force of crimped stent at 2.2-mm deflection was 1.01 ± 0.08 N, 0.82 ± 0.08 N, 0.92 ± 0.12 N, and 0.68 ± 0.07 N for each of stents A, B, C and D. The results of this study enabled us to identify several factors to enhance the performance of stents. In comparing these stents, we found that our design, stent D, which was designed by a collaborative team from seven universities, performed better than the commercial stents across all parameter of foreshortening, recoil, radial force, and flexibility. [ABSTRACT FROM AUTHOR]

Purpose: To introduce an analytical method for a quantitative determination of magnetic force on a coronary stent in the magnetic resonance imaging (MRI) magnet that is generally applicable to metallic implants. Magnetic forces on metallic implants in the MRI magnets are traditionally determined empirically by measuring deflection from the vertical plane at the central axis of the magnet and at the point of the largest force along the longitudinal axis of the magnet. Materials and Methods: Magnetic and chemical characterization of the stents was performed by a commercial magnetometer and energy-dispersive X-ray spectroscopy. Magnetic force on the stents fabricated of paramagnetic alloys (surgical stainless steel and cobalt-chromium) was determined by measuring the stent's magnetic dipole moment and employing the on-axis magnetic field profile of an MRI magnet. Results: The maximum force on the stainless steel stent was found to be F S,max = 0.18 mN, whereas on the cobalt-chromium stent it was F C,max = 0.06 mN. Conclusion: The magnetic force on the investigated paramagnetic stents is even smaller than the gravitational force acting on the stents in the Earth's gravity field, so that it has no physiological impact on the stented vessels. J. Magn. Reson. Imaging 2013;37:391-397. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Advances in interventional cardiology, particularly in better efficacy and safety of drug-eluting stents, have made percutaneous coronary revascularisation practical for most patients requiring revascularisation. While this has reduced the perceived need for coronary bypass surgery, it has also focused attention on the appropriate use of coronary stents and the complexity of choosing the right revascularisation strategy. To achieve the best outcomes, it would seem that collaboration rather than competition between cardiac surgeons and interventional cardiologists is necessary. [ABSTRACT FROM AUTHOR]

What's known on the subject? and What does the study add? Withdrawal of dual antiplatelet therapy before the recommended, 12 months for drug-eluting stents and 1 month for bare-metal stents increases the rate of major adverse coronary events and mortality. However, in those undergoing surgery the risk of bleeding is increased substantially for those on antiplatelet agents. Successful management in patients with coronary stents who must undergo elective or non-elective urological surgery should be a multidisciplinary decision. This article reviews the literature and recommends a protocol for clinical management of patients undergoing urological procedures after coronary stent placement. To review the literature on coronary stents and genitourinary surgery and provide a protocol for perioperative. The keywords, 'elective surgery', 'aspirin', 'clopidogrel', 'guidelines for percutaneous coronary intervention', and 'antiplatelet therapy after coronary stent placement' were used to search PubMed for any relevant articles relating to coronary stents. Recommendations were made based on the whether the procedures patients were exposed to placed them at low-, moderate- or high-bleeding risk based on the extent of the procedure. All elective procedures should be delayed for 1 month after bare-metal stent placement and 1 year after drug-eluting stent placement. In patients classified as low risk (endoscopy and laser prostatectomy), aspirin should be continued throughout the perioperative period and dual antiplatelet therapy should continue 24-48 h postoperatively, if there is no concern for active bleeding. In those classified as moderate risk (scrotal procedures, transurethral resection of bladder tumours, transurethral resection of the prostate, urinary sphincter placement) dual antiplatelet therapy should be discontinued 5-7 days before the procedure and continued within 7 days after procedure, if there is no concern for active bleeding, in consultation with cardiology. In high-risk procedures (cystectomy, nephrectomy, prostatectomy, penile prosthesis placement) dual antiplatelet therapy should be discontinued 10 days before the procedure and continued postoperatively within 7-10 days of the procedure, when there is no longer a concern for active bleeding with the assistance of a cardiologist. Coronary artery disease is becoming more prominent in our society, increasing the use of coronary stents and antiplatelet agents. With the proposed protocol, it is safe to proceed with surgical intervention in those that have adequate stent endothelialisation. [ABSTRACT FROM AUTHOR]

Objectives The drug-eluting stent (DES) was perceived as a revolutionary medical technology because of the lower risk of restenosis compared with bare metal stent (BMS). However, the safety of DES use was called into question in 2006 due to increased incidence of catastrophic late stent thrombosis. This study aims to describe coronary stent use in the DES era in New York State. Methods Using New York State statewide hospital discharge database, we conducted descriptive analysis and logistic regression to examine the independent impacts of the introduction of DES and of the DES safety concern on DES utilization, controlling for patient demographics, co-morbidities and hospital effects. Results In the first year following the introduction of DES technology, there was a 10-fold increase in the odds of DES use versus BMS use (AOR: 10.86, 95% CI: 9.84-11.99, P < 0.001). When the safety of DES use was called into question, the odds of DES utilization decreased by 75% over a 9-month period (AOR: 0.23, 95% CI: 0.20-0.26, P < 0.001). Conclusions Following the introduction of DES, there was a rapid adoption of DES by interventional cardiologists, followed by a rapid abandonment of DES when significant safety issues were raised. After the safety of DES was called into question, there was a reduction in the use of DES and in the use of stents in general. [ABSTRACT FROM AUTHOR]

The high frequency of contact allergy to gold in patients with dermatitis was established after exhaustive skin testing, determining the right test agent, the best concentration, and repeated test readings. Metallic gold in contact with skin is slowly ionized, permitting absorption and haptenisation. Contact allergy to gold is statistically correlated to the presence of dental gold. But in many case reports it has also been attributed to wearing gold jewellery, albeit not statistically demonstrated. Epicutaneous testing with gold salts increases the blood gold level, and by intramuscular injection systemic contact dermatitis is provoked in an allergic individual. In coronary heart disease, gold-coated intravascular stents have been shown to be correlated to contact allergy and even to an increased risk of restenosis. Gold is far from inert. [ABSTRACT FROM AUTHOR]

A new antithrombogenic stent using ion beam surface modification nanotechnology was evaluated. The ion stent is being developed to inhibit acute and chronic stent-related thrombosis. Thirty self-expanding mesh stents were fabricated from Ti-Ni metal wires with a dimension of 4 mm (diameter) × 25 mm (length) × 0.15 mm (thickness). Twenty stents were coated with type I collagen and irradiated with a He+ ion beam at an energy of 150 keV with fluences of 1 × 1014 ions/cm2 (ion stent group). Ten stents had no treatment (non-ion stent group). The self-expanding stents were implanted into the right and left peripheral femoral arteries of 15 beagle dogs (vessel diameter approximately 3 mm) via a 6Fr catheter under fluoroscopic guidance. Heparin (100 units/kg) was administered intravenously before implantation. Following stent implantation, no antiplatelet or anticoagulant drugs were administered. The 1-month patency rate for the non-ion stent group was 10% (1/10), and for the ion stent group it was 80% (16/20) with no anticoagulant or antiplatelet drugs given after stent implantation ( P = 0.0004 by Fisher's exact test). Ten stents remain patent after 2 years in vivo with no anticoagulant or antiplatelet drugs. These results indicate that He+ ion-implanted collagen-coated Ti-Ni self-expanding stents have excellent antithrombogenicity and biocompatibility. This ion stent is promising for coronary and cerebral stent applications. [ABSTRACT FROM AUTHOR]

The need for on-site cardiac surgery has been a component of guidelines for the practice of elective and emergency percutaneous coronary intervention (PCI). However, proportions of cases requiring emergency coronary artery bypass grafting (CABG) post-PCI have fallen. This audit of complications of PCI confirms the very low incidence of need for emergency CABG, despite increasingly complex PCI caseload. Although the availability of stents/antiplatelet pharmacotherapy probably has contributed to improved PCI outcomes, the avoidance of emergency CABG is not contingent on either extensive use of glycoprotein IIb/IIIa inhibitors or strategies of universal stenting. [ABSTRACT FROM AUTHOR]

This study was aimed to investigate the effect of sedation on plasma soluble P-selectin (sP-selectin) levels and initiation phase of coagulation following coronary intervention. A total of 58 patients with unstable angina were randomised into two groups of sedated ( n = 29) and nonsedated ( n = 29) patients. sP-Selectin, adrenaline, noradrenaline, von Willebrand factor (vWF), fibrinogen, platelet and troponin-I levels were measured before the intervention and at 30 min and 24 h after the intervention. In the sedated group, adrenaline, noradrenaline, sP-selectin and fibrinogen levels remained stable 30 min after the intervention (p > 0.05), whereas vWF level increased (p < 0.05). In the nonsedated group, 30-min sP-selectin (p < 0.001), adrenaline (p < 0.05), noradrenaline (p = 0.012), vWF (p < 0.001) and fibrinogen (p < 0.001) levels were found to be increased. Also, 24-h sP-selectin, vWF and fibrinogen levels for both groups showed significant increases when compared with the values both 30 h before (p < 0.001) and 30 min after the intervention (p < 0.001). Sedation before interventions reduces sP-selectin levels, initial phase of coagulation and, consequently, myocardial damage. [ABSTRACT FROM AUTHOR]

This single centre study was designed to demonstrate feasibility, safety and efficacy of the Vivant® Z stent (PFM AG, Cologne, Germany). Patients withde novolesion were recruited. Coronary angioplasty was performed with either direct stenting or after balloon predilatation. Repeated angiogram was performed 6 months later or earlier if clinically indicated. Between January to June 2003, a total of 50 patients were recruited (mean age 55.8 ± 9 years). A total of 52 lesions were stented successfully. Mean reference diameter was 2.77 mm (±0.59 SD, range 2.05–4.39 mm) with mean target lesion stenosis of 65.5% (±11.6 SD, range 50.1–93.3%). Forty-six lesions (88.5%) were American College of Cardiologist/American Heart Association class B/C types. Direct stenting was performed in 18 (34.6%) lesions. Mean stent diameter was 3.18 mm (±0.41 SD, range 2.5–4 mm), and mean stent length was 14.86 mm (±2.72 SD, range 9–18 mm). The procedure was complicated in only one case which involved the loss of side branch with no clinical sequelae. All treated lesions achieved Thrombolysis In Myocardial Infarction 3 flow. Mean residual diameter stenosis was 12.2% (±7.55 SD, range 0–22.6%) with acute gain of 1.72 mm (±0.50 SD, range 0.5–2.8). At 6 months, there was no major adverse cardiovascular event. Repeated angiography after 6 months showed a restenosis rate of 17% (defined as>50% diameter restenosis). Mean late loss was 0.96 mm (±0.48 SD) with loss index of 0.61 (±0.38 SD). The restenosis rate of those lesions less than 3.0 mm in diameter was 22.2% compared with 6.25% in those lesions more than 3.0 mm in diameter. The Vivant® Z stent was shown to be safe and efficacious with low restenosis rate inde novocoronary artery lesion. [ABSTRACT FROM AUTHOR]

In-stent restenosis is a complication which impairs the success of coronary stenting. Recently, it was supposed that a delayed hypersensitivity reaction to nickel and molybdenum might be one of the triggering factors in in-stent restenosis. We have analyzed the data collected in our centre with respect to this hypothesis. Altogether, 34 patients were investigated (24 male, 10 female). Patch tests were performed with the standard series of the German Contact Dermatitis Research Group and a metal series containing the metal components of 316 L stainless steel. A positive patch test reaction to nickel was observed in 4 (11.8%) patients. None of the patients showed sensitization to the other metals. Retrospective analysis was performed in 20 patients: 2 of these patients had a positive patch test reaction to nickel, one of whom had an in-stent restenosis, and the other not. Restenoses were predominantly observed in patients with negative patch test reactions to nickel (6/18 patients). Out of the patients who were investigated prospectively only one showed sensitization to nickel. Restenosis was observed in 2 patients: neither patient had nickel allergy. Although it still cannot be excluded that metal allergy may play a role in the restenosis process in coronary stenting, there is at present little evidence for it. [ABSTRACT FROM AUTHOR]

ABSTRACT A 76-year-old male patient was admitted for mitral valvuloplasty. He had suffered a myocardial infarction 7 months earlier, and two stents had been inserted in the left main coronary artery and left circumflex artery. Intraoperative transesophageal echocardiography revealed a 10 × 8 mm echogenic mass at the ostium of the left main coronary artery. We initially suspected severe atheromatous calcification at the coronary ostium, which might require aortotomy and removal, but we decided to perform an epiaortic ultrasonographic scan first to obtain better images and reevaluate. Epiaortic scanning with a linear sonographic probe identified the mass as a protruding coronary stent. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound, 43:135-137, 2015 [ABSTRACT FROM AUTHOR]

The main goal of this numerical study is to assess the impact of geometric design perturbations on the performance of a representative coronary stent platform. In this context, first, a design parameterization model was defined for the stent under study. After, a set of metrics characterizing stent performance, namely, vessel injury, radial recoil, bending resistance, longitudinal resistance, radial strength, the risk of fracture, prolapse index, and dogboning were evaluated within the context of a finite element analysis. Afterwards, accurate surrogate models were developed, using the efficient global optimization algorithm, as predictive tools in the execution of tasks that normally require a high number of model evaluations, such as global sensitivity analysis and visualization. In the end, the dependence of the output response surfaces on the geometric parameters was mechanically interpreted, which allowed us to understand the complex interplay that exists between the considered design variables and the defined performance metrics. In this work, we studied the impact of geometric design variation in the biomechanical performance of a representative coronary stent platform. The proposed methodology is based on the generation of surrogate models built on data generated by finite element models that assess the various stent's performance attributes for a certain geometric design. The surrogates are then used to perform sensitive analysis on the design variables and to visualize the output response surfaces for each performance attribute. [ABSTRACT FROM AUTHOR]

Background: Previous intravascular ultrasound studies suggested the association of stent underexpansion with increased risk of stent thrombosis and restenosis. However, no previous study has addressed the association of the suboptimal angiographic result with target-lesion revascularization (TLR) in patients receiving new-generation drug-eluting stents (DES)., Methods and Results: RESET (Randomized evaluation of sirolimus-eluting versus everolimus-eluting stent trial) and NEXT (NOBORI biolimus-eluting versus XIENCE/PROMUS everolimus-eluting stent trial) are prospective, multicenter, randomized "DES versus DES" trials; 3196 patients and 3235 patients were enrolled in the RESET and NEXT, respectively. Using the pooled individual patient-level data, the current study population consisted of 3679 patients who received single-lesion treatment using new-generation DES such as everolimus-eluting stent and biolimus-eluting stent. The study population was divided into 3 groups according to the residual in-stent % diameter stenosis (%DS) after stent implantation by offline quantitative coronary angiography assessed in a core angiographic laboratory (optimal group: %DS <10%, intermediate group: %DS=10% to 20%, suboptimal group: %DS ≧20%). The cumulative 3-year incidence of TLR was significantly higher in the suboptimal group than in the intermediate and optimal groups (9.8% versus 5.8% versus 5.7%, log-rank P =0.004). Even after adjusting for the clinical, angiographic, and procedural characteristics, the excess TLR risk of the suboptimal group relative to the optimal group remained significant (hazard ratio: 1.65, 95% confidence interval, 1.14-2.41, P =0.009). The excess TLR risk of the suboptimal group relative to the optimal group was consistently seen across all the subgroups including heavy calcification., Conclusions: The residual angiographic in-stent %DS ≥20% was associated with increased risk for TLR in patients treated with the new-generation DES., (© 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)