Drug-eluting stents: the past, present, and future

Coronary stent implantation links to the occurrence of eosinophilia and interstitial pneumonia: a case report and systematic review

BACKGROUND

Rapamycin has been extensively utilized for coating coronary artery stents to reduce the occurrence of restenosis, yet there has been limited research on the potential harms of rapamycin-eluting stents. Herein, We report a case of eosinophilia and interstitial pneumonia caused by a cobalt-based alloy stent eluted with rapamycin.

CASE PRESENTATION

The patient was admitted due to fever, cough, and expectoration symptoms. Previously, the patient had undergone a procedure of percutaneous coronary stent implantation in our hospital's cardiology department, which led to a gradual rise in blood eosinophil count. This time, the eosinophil count was higher than the previous admission. A chest CT scan revealed multiple flocculent density increases in both lungs and bronchiectasis. The rapamycin-eluting stents may have caused eosinophilia and interstitial pneumonia, which improved after administering corticosteroids. A systematic review of relevant literature was conducted to summarize the characteristics of interstitial pneumonia caused by drug-eluting stents.

CONCLUSION

Paclitaxel, everolimus, zotarolimus, and rapamycin are the types of drugs that can lead to drug-eluting stents, and because of the rarity of their onset, clinical doctors must be precise and prompt in diagnosing suspected cases to avoid misdiagnosis and delayed treatment.

Drug-eluting stents for coronary artery disease in the perspective of bibliometric analysis

Drug-eluting stents (DES) play a crucial role in treating coronary artery disease (CAD) by preventing restenosis. These stents are coated with drug carriers that release antiproliferative drugs within the vessel. Over the past two decades, DES have been employed in clinical practice using various materials, polymers, and drug types. Despite optimizations in their design and materials to enhance biocompatibility and antithrombotic properties, evaluating their long-term efficacy and safety necessitates improved clinical follow-up and monitoring. To delineate future research directions, this study employs a bibliometric analysis approach. We comprehensively surveyed two decades' worth of literature on DES for CAD using the Web of Science Core Collection (WOSCC). Out of 5,778 articles, we meticulously screened them based on predefined inclusion and exclusion criteria. Subsequently, we conducted an in-depth analysis encompassing annual publication trends, authorship affiliations, journal affiliations, keywords, and more. Employing tools such as Excel 2021, CiteSpace 6.2R3, VOSviewer 1.6.19, and Pajek 5.17, we harnessed bibliometric methods to derive insights from this corpus. Analysis of annual publication data indicates a recent stabilisation or even a downward trend in research output in this area. The United States emerged as the leading contributor, with Columbia University and CRF at the forefront in both publication output and citation impact. The most cited document pertained to standardized definitions for clinical endpoints in coronary stent trials. Our author analysis identifies Patrick W. Serruys as the most prolific contributor, underscoring a dynamic exchange of knowledge within the field.Moreover, the dual chart overlay illustrates a close interrelation between journals in the "Medicine," "Medical," and "Clinical" domains and those in "Health," "Nursing," and "Medicine." Frequently recurring keywords in this research landscape include DES coronary artery disease, percutaneous coronary intervention, implantation, and restenosis. This study presents a comprehensive panorama encompassing countries, research institutions, journals, keyword distributions, and contributions within the realm of DES therapy for CAD. By highlighting keywords exhibiting recent surges in frequency, we elucidate current research hotspots and frontiers, thereby furnishing novel insights to guide future researchers in this evolving field.

Drug-Coated Balloon in Primary Percutaneous Coronary Intervention

According to the latest coronary interventional guidelines, a drug-eluting stent is the recommended reperfusion therapy in primary percutaneous coronary intervention (pPCI). However, deficiencies and defects, such as in-stent restenosis (ISR), incomplete stent apposition, stent thrombosis, reinfarction after stent implantation, long-term dual antiplatelet drug use, and adverse reactions of metal implants, plague clinicians and patients. Drug-coated balloon (DCB), which delivers antiproliferative agents into the vessel wall without stent implantation and leaves no implants behind after the procedure, is a novel option for percutaneous coronary intervention and has proven to be a promising strategy in cases of ISR, small vessel coronary artery disease, and bifurcation lesions. However, most of the available experience has been gained in elective percutaneous coronary intervention, and experience in pPCI is lacking. The current evidence for the use of DCB-only in pPCI was discussed and analyzed in this review.

Drug loaded implantable devices to treat cardiovascular disease

INTRODUCTION

It is widely acknowledged that cardiovascular diseases (CVDs) continue to be the leading cause of death globally. Furthermore, CVDs are the leading cause of diminished quality of life for patients, frequently as a result of their progressive deterioration. Medical implants that release drugs into the body are active implants that do more than just provide mechanical support; they also have a therapeutic role. Primarily, this is achieved through the controlled release of active pharmaceutical ingredients (API) at the implementation site.

AREAS COVERED

In this review, the authors discuss drug-eluting stents, drug-eluting vascular grafts, and drug-eluting cardiac patches with the aim of providing a broad overview of the three most common types of cardiac implant.

EXPERT OPINION

Drug eluting implants are an ideal alternative to traditional drug delivery because they allow for accurate drug release, local drug delivery to the target tissue, and minimise the adverse side effects associated with systemic administration. Despite the fact that there are still challenges that need to be addressed, the ever-evolving new technologies are making the fabrication of drug eluting implants a rewarding therapeutic endeavour with the possibility for even greater advances.

Iron corroded granules inhibiting vascular smooth muscle cell proliferation

In-stent restenosis after interventional therapy remains a severe clinical complication. Current evidence indicates that neointimal hyperplasia induced by vascular smooth muscle cell (VSMC) proliferation is a major cause of restenosis. Thus, inhibiting VSMC proliferation is critical for preventing in-stent restenosis. The incidence of restenosis was reduced in nitrided iron-based stents (hereafter referred to as iron stents). We hypothesized that the corroded granules produced by the iron stent would prevent in-stent restenosis by inhibiting VSMC proliferation. To verify this hypothesis, we introduced a dynamic circulation device to analyze the components of corroded granules. To investigate the effects of corroded granules on VSMC proliferation, we implanted the corroded iron stent into the artery of the atherosclerotic artery stenosis model. Moreover, we explored the mechanism underlying the inhibition of VSMC proliferation by iron corroded granules. The results indicated that iron stent produced the corroded granules after implantation, and the main component of the corrosion granules was iron oxide. Remarkably, the corroded granules reduced the neointimal hyperplasia in an atherosclerotic artery stenosis model, and iron corroded granules decreased the neointimal hyperplasia by inhibiting VSMC proliferation. In addition, we revealed that corroded granules reduced VSMC proliferation by activating autophagy through the AMPK/mTOR signaling pathway. Importantly, safety of iron corroded granules was evaluated and proved to be satisfactory hemocompatibility in rabbit model. Overall, the role of corroded granules in restenosis prevention was described for the first time. This finding highlighted the implication of corroded granules produced by iron stent in inhibiting VSMC proliferation, pointing to a new direction to prevent in-stent restenosis.

Regulatory perspectives of combination products

Combination products with a wide range of clinical applications represent a unique class of medical products that are composed of more than a singular medical device or drug/biological product. The product research and development, clinical translation as well as regulatory evaluation of combination products are complex and challenging. This review firstly introduced the origin, definition and designation of combination products. Key areas of systematic regulatory review on the safety and efficacy of device-led/supervised combination products were then presented. Preclinical and clinical evaluation of combination products was discussed. Lastly, the research prospect of regulatory science for combination products was described. New tools of computational modeling and simulation, novel technologies such as artificial intelligence, needs of developing new standards, evidence-based research methods, new approaches including the designation of innovative or breakthrough medical products have been developed and could be used to assess the safety, efficacy, quality and performance of combination products. Taken together, the fast development of combination products with great potentials in healthcare provides new opportunities for the advancement of regulatory review as well as regulatory science.

Efficacy and Safety of Very Short-Term Dual Antiplatelet Therapy After Drug-Eluting Stents Implantation for Acute Coronary Syndrome: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Background and Objective: Dual antiplatelet therapy (DAPT) is the basis for preventing ischemic events after percutaneous coronary intervention (PCI), and DAPT for 12 months has been the standard strategy recommended by the guidelines. However, patients with acute coronary syndrome (ACS) have a higher risk of thrombosis, and the application of very short-term DAPT (1–3 months) in patients with ACS is consistently controversial. The purpose of this study is to explore the efficacy and safety of DAPT for 1–3 months in patients with ACS who were implanted with drug-eluting stents (DES).

Methods: We conducted a systematic review and meta-analysis of randomized controlled trials that compared the very short-term (3 months or less) with long-term (12 months or more) DAPT in patients with ACS after PCI. The randomized controlled trials were included by searching PubMed, EMBASE, and Cochrane Library database. The relative risk (RR) and 95% CIs for endpoint events were calculated by the fixed effects model, and trial sequential analysis was applied to calculate the anticipated sample size and assess the results.

Result: A total of eight randomized controlled trials with 16,492 patients who met the inclusion criteria were conducted. There were no significant statistic differences in myocardial infarction (RR 1.05, 0.82–1.35, P = 0.68), stents thrombosis (RR 1.32, 0.85–2.07, P = 0.22), all-cause death (RR 0.87, 0.66–1.13, P = 0.29), and target vessel revascularization (RR 0.93, 0.76–1.13, P = 0.47). However, there were significant differences in major bleeding (RR 0.60, 0.50–0.73, P < 0.00001) and the net adverse cardiac and cerebrovascular events (RR 0.84, 0.74–0.95, P = 0.007).

Conclusions: The strategy of DAPT for 1–3 months not only has a significant effect in patients with ACS who were implanted with DES but also reduces the risk of major bleeding. The scheme of short-term DAPT followed by P2Y₁₂ receptor inhibitor monotherapy is especially beneficial for patients with ACS. The results of this systematic review and meta-analysis are based on the application of new generation DES and new oral antiplatelet drugs in patients with ACS, which are difficult to use in the general population (Registered by PROSPERO, CRD 42020210520).

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO/, identifier: CRD 42020210520.

Quantifying stent-induced damage in coronary arteries by investigating mechanical and structural alterations

Vascular damage develops with diverging severity during and after percutaneous coronary intervention with stent placement and is the prevailing stimulus for in-stent restenosis. Previous work has failed to link mechanical data obtained in a realistic in vivo or in vitro environment with data collected during imaging processes. We investigated whether specimens of porcine right coronary arteries soften when indented with a stent strut shaped structure, and if the softening results from damage mechanisms inside the fibrillar collagen structure. To simulate the multiaxial loading scenario of a stented coronary artery, we developed the testing device 'LAESIO' that can measure differences in the stress-stretch behavior of the arterial wall before and after the indentation of a strut-like stamp. The testing protocol was optimized according to preliminary experiments, more specifically equilibrium and relaxation tests. After chemical fixation of the specimens and subsequent tissue clearing, we performed three-dimensional surface and second-harmonic generation scans on the deformed specimens. We analyzed and correlated the mechanical response with structural parameters of high-affected tissue located next to the stamp indentation and low-affected tissue beyond the injured area. The results reveal that damage mechanisms, like tissue compression as well as softening, fiber dispersion, and the lesion extent, are direction-dependent, and the severity of them is linked to the strut orientation, indentation pressure, and position. The findings highlight the need for further investigations by applying the proposed methods to human coronary arteries. Additional data and insights might help to incorporate the observed damage mechanisms into material models for finite element analyses to perform more accurate simulations of stent-implantations.

Coronary Artery Bypass Grafting vs Percutaneous Coronary Intervention in Patients With Diabetes

As percutaneous coronary intervention (PCI) continues to evolve, comparative outcomes for PCI vs coronary artery bypass grafting (CABG) remain relevant in diabetic patients. All revascularization procedures in patients with coronary artery disease and diabetes mellitus from 2010 to 2018 were included. Propensity matching was used to identify equivalent cohorts to compare revascularization strategies. Primary outcomes included 30-day, 1-year, and 5-year mortality. Multivariable analysis was used to define factors associated with major adverse cardiovascular and cerebrovascular events (MACCE). A total of 2869 patients with diabetes were divided into PCI (n = 653) and CABG (n = 2216) cohorts. Propensity matching yielded a 1:1 match consisting of 552 patients in each cohort (CABG vs PCI). Total median follow-up was 3.28 years (range: 1.83-5.00). Following propensity matching in patients with no prior PCI (1:1; n = 279), mortality remained significantly higher in the PCI cohort at 1 year (13.98% vs 7.53%; P = 0.014) and 5 years (26.88% vs 16.85%; P < 0.004). Hospital readmissions were higher for PCI patients at 1 year (16.49% vs 9.32%; P < 0.0122) and 5 years (19.71% vs 11.83%; P = 0.011). MACCE occurred more frequently in the PCI cohort (32.97% vs 21.51%; P = 0.002). Need for subsequent revascularization (6.45% vs 2.51%; P = 0.024) were significantly higher in the PCI cohort, and time interval to revascularization was significantly longer in the CABG cohort (3.48 [2.11-5.17] vs 2.62 [1.33-4.25] years; P < 0.001). The current study reports improved survival, fewer long-term hospital readmissions, and reduced MACCE and need for repeat revascularization in the CABG cohort. Given these data, patients with diabetes mellitus and coronary artery disease may fare better with surgical revascularization, compared to PCI.

Computational model of stent-based delivery from a half-embedded two-layered coating

An attempt is made in the present investigation to develop a computational model for the purpose of studying the effect of interstitial flow in the porous media on the distribution of drug eluted from a half-embedded drug-eluting stent and its retention in the presence of two-layered coating of the stent. The transport of free drug inside the coatings is considered as an unsteady diffusion process while that in the tissue as an unsteady convection-diffusion-reaction process. The bound drug is governed by an unsteady reaction process only. Immersed boundary method (IBM) in the staggered grid formulation, popularly known as marker and cell (MAC) method, has been leveraged to tackle numerically the governing equations. This model highlights the benefits of consideration of two-layered coating and does predict underlying mechanism for better efficacy by tweaking the kinetics parameters. Comparisons are also made with the results available for stent-based delivery.

Relationship Between Stent Diameter, Platelet Reactivity, and Thrombotic Events After Percutaneous Coronary Artery Revascularization

Small vessel diameter and residual platelet reactivity are independent predictors of thrombotic events after percutaneous coronary intervention (PCI). We sought to determine whether an interaction exists between residual platelet reactivity and stent diameter regarding the occurrence of stent thrombosis and other adverse events after PCI. We stratified patients in the prospective ADAPT-DES registry who underwent single-lesion PCI according to if they received a small diameter stent (SDS, defined as a stent with a diameter of 2.25 mm). Patients receiving an SDS were compared with patients receiving a stent ≥2.5 mm using Kaplan-Meier rates and multivariable Cox proportional hazards regression. We defined major adverse cardiac events (MACE) as the composite of cardiac death, myocardial infarction, and stent thrombosis (ST). Among 5,608 patients who underwent single-lesion PCI in ADAPT-DES, 222 (4.0%) patients received an SDS. Patients with an SDS were more likely than patients without an SDS to have 3-vessel disease but received, on average, fewer stents and were less likely to present with a thrombotic lesion. Receiving versus not receiving an SDS was associated with increased risk of ST (adjusted hazard ratio 4.35, 95% confidence interval 1.95 to 9.73, p <0.001) as well as MACE (adjusted hazard ratio 1.75, 95% confidence interval 1.11 to 2.75, p = 0.02). There was no statistical interaction between platelet reactivity and SDS regarding ST (p = 0.12) or MACE (p = 0.51). In conclusion, PCI with small drug-eluting stents is associated with a high risk of thrombotic events, including ST. Further studies should explore whether alternative treatment strategies are appropriate in small vessels.

Noninvasive in vivo Assessment of the Re-endothelialization Process Using Ultrasound Biomicroscopy in the Rat Carotid Artery Balloon Injury Model

OBJECTIVES

Ultrasound biomicroscopy (UBM), or ultra high-frequency ultrasound, is a technique used to assess the anatomy of small research animals. In this study, UBM was used to assess differences in intimal hyperplasia thickness as a surrogate measurement of the re-endothelialization process after carotid artery balloon injury in rats.

METHODS

Ultrasound biomicroscopic data from 3 different experiments and rat strains (Sprague Dawley, Wistar, and diabetic Goto-Kakizaki) were analyzed. All animals were subjected to carotid artery balloon injury and examined with UBM (30-70 MHz) 2 and 4 weeks after injury. Re-endothelialization on UBM was defined as the length from the carotid bifurcation to the most distal visible edge of the intimal hyperplasia. En face staining with Evans blue dye was performed at euthanasia 4 weeks after injury, followed by tissue harvesting for histochemical and immunohistochemical evaluations.

RESULTS

A significant correlation (Spearman r = 0.63; P < .0001) was identified when comparing all measurements of re-endothelialization obtained from UBM and en face staining. The findings revealed a similar pattern for all rat strains: Sprague Dawley (Spearman r = 0.70; P < .0001), Wistar (Spearman r = 0.36; P < .081), and Goto-Kakizaki (Spearman r = 0.70; P < .05). A Bland-Altman test showed agreement between en face staining and UBM. Immunohistochemical staining confirmed the presence of the endothelium in the areas detected as re-endothelialized by the UBM assessment.

CONCLUSIONS

Ultrasound biomicroscopy can be used for repeated in vivo assessment of re-endothelialization after carotid artery balloon injury in rats.

In vitro and in vivo evaluation of a dextran-graft-polybutylmethacrylate copolymer coated on CoCr metallic stent

Introduction: The major complications of stent implantation are restenosis and late stent thrombosis. PBMA polymers are used for stent coating because of their mechanical properties. We previously synthesized and characterized Dextrangraft-polybutylmethacrylate copolymer (Dex-PBMA) as a potential stent coating. In this study, we evaluated the haemocompatibility and biocompatibility properties of Dex-PBMA in vitro and in vivo. Methods: Here, we investigated: (1) the effectiveness of polymer coating under physiological conditions and its ability to release Tacrolimus®, (2) the capacity of Dex-PBMA to inhibit Staphylococcus aureus adhesion, (3) the thrombin generation and the human platelet adhesion in static and dynamic conditions, (4) the biocompatibility properties in vitro on human endothelial colony forming cells ( ECFC) and on mesenchymal stem cells (MSC) and in vivo in rat models, and (5) we implanted Dex-PBMA and Dex-PBMA_TAC coated stents in neointimal hyperplasia restenosis rabbit model. Results: Dex-PBMA coating efficiently prevented bacterial adhesion and release Tacrolimus®. Dex-PBMA exhibit haemocompatibility properties under flow and ECFC and MSC compatibility. In vivo, no pathological foreign body reaction was observed neither after intramuscular nor intravascular aortic implantation. After Dex-PBMA and Dex-PBMA_TAC coated stents 30 days implantation in a restenosis rabbit model, an endothelial cell coverage was observed and the lumen patency was preserved. Conclusion: Based on our findings, Dex-PBMA exhibited vascular compatibility and can potentially be used as a coating for metallic coronary stents.

Clinical outcomes of bioresorbable vascular scaffold to treat all-comer patients. Are patients with acute coronary syndrome better candidates for bioresorbable vascular scaffold?

BACKGROUND

Scaffold thromboses (ST) and adverse events and have been associated with bioresorbable vascular scaffolds (BVS) at long-term, but their mechanism remains unclear. We sought to evaluate patient and lesion characteristics associated with mid- to long-term outcomes in patients treated with BVS.

METHODS

This is an observational single-center, single-arm, retrospective study evaluating the performance of BVS in an all-comer population, including complex lesions (chronic total occlusions, long lesions), small vessels, and acute coronary syndromes (ACS).

RESULTS

From May 2013 to June 2015, we included 482 patients (580 lesions) that were treated with BVS implantation including 71.2% treated for ACS in the present analysis. Mean follow-up period was 816.2 ± 242.6 days. The primary endpoint was device oriented cardiac events (DOCE), defined as a composite of target-lesion revascularization (TLR), ST, target vessel myocardial infarction (TVMI) and cardiac death. Using Kaplan-Meier methods, the DOCE and ST rates at 36 months were 9.4% and 2.3%, respectively. No ST occurred between 2 and 3 years and ST occurred after 3 years, in one patient. Using multivariate analysis, ACS was the only significant predictor of lower rates of DOCE (p = 0.04, HR: 0.47, 95% CI: 0.23-0.96).

CONCLUSIONS

In this large all-comers real-world cohort, lesions treated with BVS had non-negligible rates of DOCE and ST, in line with previous published randomized trials. The occurrence of very late event was very low after 24 months. ACS patients had lower rates of DOCE.

Comparison of drug-eluting balloon versus drug-eluting stent for treatment of coronary artery disease: a meta-analysis of randomized controlled trials

Background

Drug-eluting balloons (DEB) have significant value for treating coronary artery disease (CAD). However, the merits of using DEB versus drug-eluting stents (DES) to treat CAD remain controversial. Herein, we conducted a meta-analysis to compare the safety and efficacy of DEB and DES for treatment of CAD.

Methods

We searched MEDLINE, EMBASE, and CENTRAL databases for eligible trials comparing DEB with DES for treatment of CAD. The primary endpoint was major adverse cardiac events (MACE); the secondary endpoints included in-lesion late lumen loss (LLL), binary restenosis (BR), myocardial infarction (MI), target lesion revascularization (TLR) and mortality.

Results

Twenty-three trials with a total of 2712 patients were included. There were no significant differences in the primary endpoint of MACE between the DEB and DES groups (Risk Ratio (RR) 1.19; 95% confidence interval (CI) (0.87, 1.63); P = 0.27), or in the clinical outcomes of each of MACE’s components, including TLR, MI and mortality. However, efficacy was significantly different between the DEB and DES groups, especially when we compared DEB to second-generation DES: in-lesion LLL (Mean Difference (MD) 0.11; (0.01, 0.22); P = 0.03); binary restenosis (RR 1.46; (1.00, 2.13); P = 0.05).

Conclusions

DEB is equivalent to DES in terms of safety for managing CAD, and DEB may be considered as an alternative choice for treatment of CAD.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0771-y) contains supplementary material, which is available to authorized users.

Drug delivery across length scales

Over the last century, there has been a dramatic change in the nature of therapeutic, biologically active molecules available to treat disease. Therapies have evolved from extracted natural products towards rationally designed biomolecules, including small molecules, engineered proteins and nucleic acids. The use of potent drugs which target specific organs, cells or biochemical pathways, necessitates new tools which can enable controlled delivery and dosing of these therapeutics to their biological targets. Here, we review the miniaturisation of drug delivery systems from the macro to nano-scale, focussing on controlled dosing and controlled targeting as two key parameters in drug delivery device design. We describe how the miniaturisation of these devices enables the move from repeated, systemic dosing, to on-demand, targeted delivery of therapeutic drugs and highlight areas of focus for the future.

MicroRNA-206 regulates vascular smooth muscle cell phenotypic switch and vascular neointimal formation

MiR-206 has been found to play a critical role in skeletal muscle proliferation, differentiation, and regeneration. However, little is known about the function of miR-206 in vascular smooth muscle cells (VSMCs) biology. In this study, we will investigate its roles in phenotypic switching of VSMCs and neointimal lesion formation. First, we identified the expression of miR-206 in VSMCs treated with various concentrations of TGFβ1 and in rat carotid arteries after angioplasty by using qPCR. TGFβ1 inhibited the expression of miR-206 and TGFβ1 inhibitor induced miR-206 expression. In VSMCs of injured vascular walls, miR-206 expression was upregulated. Then, we overexpressed miR-206 using lentivirus Lv-rno-mir-206 and knocked down miR-206 using LV-rno-mir-206-inhibitor in rat carotid arteries after angioplasty. Overexpression of miR-206 resulted in decreasing SM22α expression in VSMCs in vitro and knockdown of miR-206 suppressed neointimal lesion formation in vivo. Finally, ZFP580 (zinc finger protein 580) was identified as the direct target of miR-206 in VSMCs by using luciferase report assay. The results indicate that miR-206 is involved in phenotypic switching of VSMCs and neointimal lesion formation after angioplasty through targeting ZFP580. These findings may provide a novel therapeutic target in post-angioplasty restenosis.

Everolimus-Eluting Bioresorbable Vascular Scaffold in Real World Practice - A Single Center Experience

BACKGROUND

Drug-eluting stents are widely used in coronary artery intervention. However, vessel caging and very late thrombotic events are of persistent and substantial concern. Bioresorbable vascular scaffolds (BVS) were developed to deliver vascular reparative therapy, by eliminating permanent mechanical restraint. However, data regarding its clinical performance is lacking.

METHODS

After the BVS implantation procedure received national approval in May 2014, patients receiving BVS implantation until November 2014 in National Taiwan University Hospital (NTUH) were enrolled. Clinical variables, angiographic data, procedural details, and follow-up information were collected and compared with those receiving BVS at NTUH as part of the global ABSORB EXTEND trial.

RESULTS

A total of 35 patients (38 target vessels) with 48 BVS implanted after approval were enrolled, as the "real-world practice" group. Data of the 34 patients (34 target vessels) with 37 BVS implanted in the ABSORB EXTEND trial were also obtained. Differences in lesion complexity (0% type B2/C lesion in ABSORB EXTEND, versus 23.7% in real-world, p = 0.007) and lesion length (20.9 ± 6.1 mm in ABSORB EXTEND, versus 29.5 ± 15.9 mm in real-world, p = 0.008) were noted. The ischemia-driven target vessel revascularization after an average of 732 days follow-up was 11.8% in the ABSORB EXTEND trial. However, there was no ischemia-driven target lesion revascularization (TLR), no scaffold thrombosis, no myocardial infarction (MI), and no patients passed during the follow-up period. In real-world patients, there is 5.3% of MI, 2.6% ischemia-driven TLR, and 2.6% of non-fatal probable scaffold thrombosis.

CONCLUSIONS

The use of BVS in real-world practice is feasible, with clinical outcomes comparable to those in the ABSORB EXTEND trial.

Sex-based influence on clinical outcomes after drug-eluting stent implantation in real-world patients: insight from the FOCUS registry

OBJECTIVES

To investigate the impact of sex on clinical outcomes after drug-eluting stent (DES) implantation in real-world patients.

METHODS AND RESULTS

A total number of 4720 patients (3365 males and 1355 females) undergoing the second-generation cobalt-chromium sirolimus-eluting stent (CoCr-SES) implantation from the FOCUS registry were included in this analysis. The cumulative incidences of major adverse cardiovascular event (MACE) (1.5% vs. 2.4%; p = .03), cardiovascular death (0.5% vs. 1.0%; p = .02) and target vessel revascularization (TVR) (0.3% vs. 0.8%; p = .01) within six months were significantly higher in females and the risks of MACE (adjusted hazard ratio [HR] 0.5 (0.3-0.9); p = .01) and TVR (adjusted HR 0.1(0.0-0.5); p = .001) remained significant in multivariate analysis. Reversely, the cumulative incidences of MACE (5.4% vs. 4.8%; p = .04) and any revascularization (5.1% vs. 3.3%; p = .01) were significantly higher in males beyond six months and the risks of all-cause death (adjusted HR 1.6 (1.1-2.5); p = .03) and cardiovascular death (adjusted HR 1.9 (1.1-3.6); p = .03) turned out to be significant in multivariate analysis. Notes: All cumulative incidences were presented as male vs. female; all HRs were calculated as male relative to female.

CONCLUSIONS

Females were associated with higher risk of early adverse events, while, males were associated with higher risk of late adverse events. Key messages Females undergoing PCI are typically older, have more cardiovascular risk factors, while, males in need of PCI are more frequently associated with complex lesions. The overall three-year cumulative incidences of adverse events are not significantly different between males and females but numerically higher in males. Females are associated with significantly higher risks of MACE and TVR within six months, while, males are associated with significantly higher risk of all-cause mortality and cardiac mortality beyond 6 months.

Reduced duration of dual antiplatelet therapy using an improved drug-eluting stent for percutaneous coronary intervention of the left main artery in a real-world, all-comer population: Rationale and study design of the prospective randomized multicenter IDEAL-LM trial

BACKGROUND

Continuous improvements in stent technology make percutaneous coronary intervention (PCI) a potential alternative to surgery in selected patients with unprotected left main coronary artery (uLMCA) disease. The optimal duration of dual antiplatelet therapy (DAPT) in these patients remains undetermined, and in addition, new stent designs using a bioabsorbable polymer might allow shorter duration of DAPT.

STUDY DESIGN

IDEAL-LM is a prospective, randomized, multicenter study that will enroll 818 patients undergoing uLMCA PCI. Patients will be randomized in a 1:1 fashion to intravascular ultrasound-guided PCI with the novel everolimus-eluting platinum-chromium Synergy stent with a biodegradable polymer (Boston Scientific, Natick, MA) followed by 4 months of DAPT or the everolimus-eluting cobalt-chromium Xience stent (Abbott Vascular, Santa Clara, CA) followed by 12 months of DAPT. The total follow-up period will be 5 years. A subset of 100 patients will undergo optical coherence tomography at 3 months.

END POINTS

The primary end point will be major adverse cardiovascular events (composite of all-cause mortality, myocardial infarction, and ischemia-driven target vessel revascularization) at 2 years. Secondary end points will consist of the individual components of the primary end point, procedural success, a device-oriented composite end point, stent thrombosis as per Academic Research Consortium criteria, and bleeding as per Bleeding Academic Research Consortium criteria.

SUMMARY

IDEAL-LM is designed to assess the safety and efficacy of the novel Synergy stent followed by 4 months of DAPT vs the Xience stent followed by 12 months of DAPT in patients undergoing uLMCA PCI. The study will provide novel insights regarding optimal treatment strategy for patients undergoing PCI of uLMCA disease (www.clinicaltrials.gov, NCT 02303717).

Protective Aptitude of Annexin A1 in Arterial Neointima Formation in Atherosclerosis-Prone Mice-Brief Report

OBJECTIVE

Restenosis as a consequence of arterial injury is aggravated by inflammatory pathways. Here, we investigate the role of the proresolving protein annexin A1 (AnxA1) in healing after wire injury.

APPROACH AND RESULTS

Apoe^-/- and Apoe^-/-Anxa1^-/- mice were subjected to wire injury while fed a high-cholesterol diet. Subsequently, localization of AnxA1 and AnxA1 plasma levels were examined. AnxA1 was found to localize within endothelial cells and macrophages in the neointima. Levels of AnxA1 in the plasma and its lesional expression negatively correlated with neointima size, and in the absence of AnxA1, neointima formation was aggravated by the accumulation and proliferation of macrophages. In contrast, reendothelialization and smooth muscle cell infiltration were not affected in Apoe^-/-Anxa1^-/- mice.

CONCLUSIONS

AnxA1 is protective in healing after wire injury and could, therefore, be an attractive therapeutic compound to prevent from restenosis after vascular damage.

TLR3 and TLR4 as potential clinical biomarkers for in-stent restenosis in drug-eluting stents patients

In-stent restenosis is still a clinic trouble for percutaneous coronary intervention in drug-stent era. The molecular basis of restenosis is intensively associated with inflammation. TLR3 and TLR4 as innate immune factors have been proven to play a key role in atherosclerosis disease. The aim of this study is to study the TLR3 and TLR4 expressions and their downstream signaling proteins in the inflammatory process of restenosis after drug-stent therapy. mRNA and protein expression of TLR3 and TLR4 were detected in peripheral blood monocytes of primary group (n = 38), N-ISR group (n = 36) and ISR group (n = 33). Some inflammatory factors (including TLR3 and TLR4) were evaluated in serum of three groups. mRNA and protein expression of TLR3 and TLR4 and their downstream signaling proteins have shown a higher level in restenosis patients than non-restenosis patients and even primary patients who accepted first stent therapy. In serum, different from some nonspecific and downstream inflammatory factors, TLR3 and TLR4 also show a significantly higher level in ISR group compared with N-ISR group and primary group. This study provides a potential clinical biomarker for in-stent restenosis in drug-stent patients and some interesting data about the role of TLRs and their downstream signaling factors in the inflammatory process of in-stent restenosis. Compared with first stent therapy and non-restenosis patients, it is hopeful that TLR3 and TLR4 are potential noninvasive biomarkers in prognosis restenosis.

A Rat Carotid Balloon Injury Model to Test Anti-vascular Remodeling Therapeutics

The rat carotid balloon injury is a well-established surgical model that has been used to study arterial remodeling and vascular cell proliferation. It is also a valuable model system to test, and to evaluate therapeutics and drugs that negate maladaptive remodeling in the vessel. The injury, or barotrauma, in the vessel lumen caused by an inflated balloon via an inserted catheter induces subsequent neointimal growth, often leading to hyperplasia or thickening of the vessel wall that narrows, or obstructs the lumen. The method described here is sufficiently sensitive, and the results can be obtained in relatively short time (2 weeks after the surgery). The efficacy of the drug or therapeutic against the induced-remodeling can be evaluated either by the post-mortem pathological and histomorphological analysis, or by ultrasound sonography in live animals. In addition, this model system has also been used to determine the therapeutic window or the time course of the administered drug. These studies can leadto the development of a better administrative strategy and a better therapeutic outcome. The procedure described here provides a tool for translational studies that bring drug and therapeutic candidates from bench research to clinical applications.

Long-term performance of the second-generation cobalt-chromium sirolimus-eluting stents in real-world clinical practice: 3-year clinical outcomes from the prospective multicenter FOCUS registry

BACKGROUND

The short- and mid-term outcomes of the second-generation cobalt-chromium sirolimus-eluting stent (CoCr-SES) in real-world patients had been reported previously, but the long-term performance remained unclear. The objective of this analysis was to evaluate the long-term safety and efficacy of the second-generation CoCr-SES from the FOCUS registry.

METHODS

The FOCUS registry (ClinicalTrials.gov Identifier: NCT00868829) enrolled all-comers eligible to receive Firebird-2 CoCr-SES. Follow-up was continued to 3 years to evaluate long-term safety and effectiveness of the second-generation CoCr-SES in real-world practice. Results of the extended-use group and standard-use group are compared to explore performance of CoCr-SES in more severe patients with more complex lesions.

RESULTS

The rate of 3-year MACE was 7.37%, consisting of 84 cases (1.78%) of cardiac death, 166 cases (3.52%) of MI and 98 cases (2.08%) of TVR. ARC definite/probable stent thrombosis happened in 34 (0.72%) patients, only 3 new cases (<0.1%) of very late stent thrombosis was reported in the third year. Meanwhile, the difference of MACE (7.77% vs. 6.06%; P=0.058), TLF (4.71% vs. 3.49%; P=0.085) and ARC definite/probable stent thrombosis (0.83% vs. 0.37%; P=0.116) between extended-use group and standard-use group showed no significance.

CONCLUSIONS

The second-generation CoCr-SES was associated with continued low rates of 3-year MACE, TLF and stent thrombosis in a broad spectrum of patients.

Drug deposition in coronary arteries with overlapping drug-eluting stents

Drug-eluting stents are accepted as mainstream endovascular therapy, yet concerns for their safety may be under-appreciated. While failure from restenosis has dropped to below 5%, the risk of stent thrombosis and associated mortality remain relatively high. Further optimization of drug release is required to minimize thrombosis risk while maintaining therapeutic dose. The complex three-dimensional geometry of deployed stents together with the combination of diffusive and advective drug transport render an intuitive understanding of the situation exceedingly difficult. In situations such as this, computational modeling has proven essential, helping define the limits of efficacy, determine the mode and mechanism of drug release, and identify alternatives to avoid toxicity. A particularly challenging conformation is encountered in coronary arteries with overlapping stents. To study hemodynamics and drug deposition in such vessels we combined high-resolution, multi-scale ex vivo computed tomography with a flow and mass transfer computational model. This approach ensures high geometric fidelity and precise, simultaneous calculation of blood flow velocity, shear stress and drug distribution. Our calculations show that drug uptake by the arterial tissue is dependent both on the patterns of flow disruption near the wall, as well as on the relative positioning of drug-eluting struts. Overlapping stent struts lead to localized peaks of drug concentration that may increase the risk of thrombosis. Such peaks could be avoided by anisotropic stent structure or asymmetric drug release designed to yield homogeneous drug distribution along the coronary artery and, at the least, suggest that these issues need to remain in the forefront of consideration in clinical practice.

Drug-eluting balloons in the treatment of de-novo coronary lesions: a meta-analysis of randomized-controlled trials

AIM

The aim of this meta-analysis was to evaluate the efficacy of drug-eluting balloons (DEBs) plus bare-metal stents (BMS) for the treatment of de-novo coronary lesions.

METHODS AND RESULTS

Eleven trials involving 1279 patients were included in this study. The main endpoints were as follows: late lumen loss (LLL), binary restenosis, stent thrombosis (ST), and major adverse cardiovascular events (MACEs). The definition of MACEs was a composite of death, myocardial infarction (MI), and target lesion revascularization (TLR). Compared with BMS alone, DEB plus BMS showed a lower risk for LLL (P=0.007) and MACEs (P=0.010). There were no significant differences in binary restenosis (P=0.212), ST (P=0.199), death (P=0.141), MI (P=0.439), and TLR (P=0.340). Compared with drug-eluting stents (DES), DEB plus BMS could increase the risk of LLL (P=0.002) and MACEs (P=0.026). The risks of binary restenosis (P=0.113), ST (P=0.832), death (P=0.115), MI (P=0.831), and TLR (P=0.111) were similar between DEB plus BMS and DES.

CONCLUSION

DEB plus BMS was better than BMS alone in reducing LLL and MACEs, especially when dilatation was performed after stenting for de-novo coronary lesions, but it was inferior to DES. Therefore, the treatment strategy with DEB plus BMS should not be recommended for de-novo coronary lesions, except for patients who have contraindications for DES.

Re-Endothelialization Study on Endovascular Stents Seeded by Endothelial Cells through Up- or Downregulation of VEGF

We studied the effects of gene transfection of endothelial cells with vascular endothelial growth factor (VEGF) on re-endothelialization and inhibition of in-stent restenosis. Transfected endothelial cells (ECs) exposed to different VEGF levels were seeded on a stent surface for evaluation in vitro. VEGF121(++) ECs and VEGF121(--) ECs were established using lentiviral-mediated HUVECs transfection. VEGF RNA transcription level and VEGF protein expression were detected by qPCR, Western blot, and ELISA. Methyl thiazolyl tetrazolium (MTT) assay, wound healing assay, and in vitro HUVEC tube formation assay showed that VEGF overexpression promoted cell proliferation, migration, and endothelial capillary-like tube formation. Downregulation of VEGF expression inhibited these activities. Using a rotational culturing system, cells tightly adhered on the stent surface. Stents seeded with transfected ECs at different VEGF levels were implanted in abdominal aortas of New Zealand white rabbits to study re-endothelialization and inhibition of in-stent restenosis. Stents with cells exposed to excess VEGF expression were almost completely covered with cells after stent implantation for 1 week (w). In the VEGF interference group this process was delayed over 4 w due to RNAi-mediated silencing of VEGF. Cryosectioning after 12 w showed that stents seeded with HUVECs exposed to excess VEGF expression significantly reduced the neointima area and stenosis when compared with bare metal stents and stents from the VEGF interference group. Transgenic HUVECs were not found in tissues of experimental animals. Furthermore, cells from these tissues were similar to those from normal tissue. In conclusion, VEGF-mediated endothelialization was found. Furthermore, ECs exposed to VEGF overexpression reduced neointimal hyperplasia, promoted endothelialization, and reduced in-stent restenosis.

Mechanical response of cardiovascular stents under vascular dynamic bending

Backround

Currently, the effect of vascular dynamic bending (VDB) has not been fully considered when studying cardiovascular stents’ long-term mechanical properties, as the previous studies about stent’s mechanical properties mostly focus on the effect of vascular pulsation (VP). More and more clinical reports suggested that the effect of VDB have a significant impact on stent.

Methods

In this paper, an explicit-implicit coupling simulation method was applied to analyze the mechanical responses of cardiovascular stents considering the effect of VDB. The effect of VP on stent mechanical properties was also studied and compared to the effect of VDB.

Results

The results showed that the dynamic bending deformation occurred in stents due to the effect of VDB. The effects of VDB and VP resulted in alternating stress states of the stent, while the VDB alternate stresses effective on the stent were almost three times larger than that of the VP. The stress concentration under VDB mainly occurred in bridge struts and the maximal stress was located in the middle loops of the stent. However, the stress distributed uniformly in the stents under the effect of VP. Stent fracture occurred more frequently as a result of VDB with the predicted fracture position located in the bridging struts of the stent. These results are consistent with the reported data in clinical literatures. The stress of the vessel under VDB was higher, than that caused by VP.

Conclusions

The results showed that the effect of VDB has a significant impact on the stent’s stress distribution, fatigue performance and overall stress on the vessel, thus it is necessary to be considered when analyzing stent’s long-term mechanical properties. Meanwhile, the results showed that the explicit-implicit coupling simulation can be applied to analyze stent mechanical properties.

Comprehensive Proteomic Analysis of Mesenchymal Stem Cell Exosomes Reveals Modulation of Angiogenesis via Nuclear Factor-KappaB Signaling

Mesenchymal stem cells (MSC) are known to facilitate healing of ischemic tissue related diseases through proangiogenic secretory proteins. Recent studies further show that MSC derived exosomes function as paracrine effectors of angiogenesis, however, the identity of which components of the exosome proteome responsible for this effect remains elusive. To address this we used high-resolution isoelectric focusing coupled liquid chromatography tandem mass spectrometry, an unbiased high throughput proteomics approach to comprehensively characterize the proteinaceous contents of MSCs and MSC derived exosomes. We probed the proteome of MSCs and MSC derived exosomes from cells cultured under expansion conditions and under ischemic tissue simulated conditions to elucidate key angiogenic paracrine effectors present and potentially differentially expressed in these conditions. In total, 6,342 proteins were identified in MSCs and 1,927 proteins in MSC derived exosomes, representing to our knowledge the first time these proteomes have been probed comprehensively. Multilayered analyses identified several putative paracrine effectors of angiogenesis present in MSC exosomes and increased in expression in MSCs exposed to ischemic tissue-simulated conditions; these include platelet derived growth factor, epidermal growth factor, fibroblast growth factor, and most notably nuclear factor-kappaB (NFkB) signaling pathway proteins. NFkB signaling was identified as a key mediator of MSC exosome induced angiogenesis in endothelial cells by functional in vitro validation using a specific inhibitor. Collectively, the results of our proteomic analysis show that MSC derived exosomes contain a robust profile of angiogenic paracrine effectors, which have potential for the treatment of ischemic tissue-related diseases.