Localized Hypersensitivity and Late Coronary Thrombosis Secondary to a Sirolimus-Eluting Stent

Carotid single- and dual-layer stents reduce the wall adhesion of platelets by influencing flow and cellular transport

An ongoing thrombosis on a ruptured atherosclerotic plaque in the carotid may cause stroke. The primary treatment for patients with tandem lesion is stenting. Dual-layer stents have been introduced as an alternative to single-layer stents for elective and emergent carotid artery stenting. While the dual-layer structure shows promise in reducing plaque prolapse through the stent struts and with it the occurrence of post-procedural embolism, there are early signs that this newer generation of stents is more thrombogenic. We investigate a single- and a dual-layer stent design to assess their influence on a set of thrombosis-related flow factors in a novel setup of combined experiments and simulations. The in vitro results reveal that both stents reduce thrombus formation by approximately 50% when human anticoagulated whole blood was perfused through macrofluidic flow chambers coated with either collagen or human atherosclerotic plaque homogenates. Simulations predict that the primary cause is reduced platelet presence in the vicinity of the wall, due to the influence of stents on flow and cellular transport. Both stents significantly alter the near-wall flow conditions, modifying shear rate, shear gradient, cell-free zones, and platelet availability. Additionally, the dual-layer stent has further increased local shear rates on the inner struts. It also displays increased stagnation zones and reduced recirculation between the outer-layer struts. Finally, the dual-layer stent shows further reduced adhesion over an atherosclerotic plaque coating. The novel approach presented here can be used to improve the design optimization process of cardiovascular stents in the future by allowing an in-depth study of the emerging flow characteristics and agonist transport.

Challenges and advances in device-related thrombus in left atrial appendage occlusion

Oral anticoagulation therapy (OAC) is a mainstay for mitigating stroke and other embolic events in patients with atrial fibrillation (AF). Despite the demonstrated efficacy of OAC in reducing events, many patients are unable to tolerate OAC due to bleeding risks. Left atrial appendage occlusion (LAAO) devices were developed as implantable technologies to moderate stroke risk in patients with intolerance to OAC. Despite clinical data supporting near-comparable protection against thromboembolic events with OAC, device-related thrombus formation has emerged as a critical complication following LAAO that remains a potential limitation to the safety and efficacy of LAAO. Improved biocompatibility of LAAO devices with fluoropolymers, a well-established stent-coating technology used to reduce thrombus formation and promote endothelialization, may optimize outcomes after LAAO.

Involvement of peptidylarginine deiminase 4 in eosinophil extracellular trap formation and contribution to citrullinated histone signal in thrombi

BACKGROUND

Extracellular traps formed by neutrophils (NETs) and eosinophils (EETs) have been described in coronary thrombi, contributing to thrombus stability. A key mechanism during NET formation is histone modification by the enzyme PAD4. Citrullinated histones, the product of PAD4 activity, are often attributed to neutrophils. Eosinophils also express high levels of PAD4.

OBJECTIVES

We aimed to explore the contribution of PAD4 to EET formation.

METHODS

We performed immunohistological analyses on thrombi, including a large, intact, and eosinophil-containing thrombus retrieved from the right coronary artery using an aspiration catheter and stroke thrombi from thrombectomy retrieval. We studied eosinophils for their capability to form PAD4-dependent EETs in response to strong ET-inducing agonists as well as activated platelets and bacteria.

RESULTS

Histopathology and immunofluorescence microscopy identified a coronary thrombus rich in platelets and neutrophils, with distinct areas containing von Willebrand factor and citrullinated histone H3 (H3Cit). Eosinophils were also identified in leukocyte-rich areas. The majority of the H3Cit+ signal colocalized with myeloperoxidase, but some colocalized with eosinophil peroxidase, indicating EETs. Eosinophils isolated from healthy volunteers produced H3Cit+ EETs, indicating an involvement of PAD4 activity. The selective PAD4 inhibitor GSK484 blocked this process, supporting PAD4 dependence of H3Cit+ EET release. Citrullinated histones were also present in EETs produced in response to live Staphylococci. However, limited evidence for EETs was found in mouse models of venous thrombosis or infective endocarditis.

CONCLUSION

As in NETosis, PAD4 can catalyze the formation of EETs. Inhibition of PAD4 decreases EET formation, supporting the future utility of PAD4 inhibitors as possible antithrombotic agents.

Revolutionizing Cardiovascular Frontiers: A Dive Into Cutting-Edge Innovations in Coronary Stent Technology

Plain balloon angioplasty was the initial method used to enlarge the intracoronary lumen size. However, it was linked to acute coronary closure due to early vessel recoil. This led to the invention of coronary stents, which offer mechanical support to open and maintain the vascular lumen. Nevertheless, the metallic scaffold introduced other issues, such as thrombosis and restenosis caused by neointimal proliferation. To address these concerns, polymers were employed to cover the scaffold, acting as drug reservoirs and regulators for controlled drug release. The use of polymers prevents direct contact between blood and metallic scaffolds. Drugs within the stent were incorporated to inhibit proliferation and expedite endothelialization in the healing process. Despite these advancements, adverse effects still arise due to the inflammatory reaction caused by the polymer material. Consequently, resorbable polymers and scaffolds were later discovered, but they have limitations and are not universally applicable. Various scaffold designs, thicknesses, materials, polymer components, and drugs have their own advantages and complications. Each stent generation has been designed to address the shortcomings of the preceding generation, yet new challenges continue to emerge. Conflicting data regarding the long-term safety and efficacy of coronary stents, especially in the extended follow-up, further complicates the assessment.

Non-invasive recanalization of first-generation sirolimus-eluting stent thrombosis due to stent fracture and coronary artery aneurysm after clopidogrel treatment 15 years after implantation

In 2020, a 48-year-old male patient was admitted to our hospital due to unstable angina. In 2005, three first-generation sirolimus-eluting stents (1st-SESs) had been deployed to his right coronary artery (RCA). Over the past 10 years or so, the patient has been treated with single antiplatelet therapy using aspirin. Coronary angiography (CAG) revealed severe stenosis in the left circumflex artery (LCx) and total occlusion at the proximal portion of the stented RCA. Furthermore, fluoroscopy showed multiple 1st-SES fractures. After ad hoc percutaneous coronary intervention of the LCx, dual antiplatelet therapy (DAPT) was resumed by adding the P2Y12 inhibitor clopidogrel to aspirin. Two months later, CAG revealed complete recanalization and multiple peri-stent coronary artery aneurysms (CAAs) in the RCA. Intravascular ultrasound revealed late-acquired stent malapposition (LSM) and formation of true aneurysms. Coronary angioscopy showed the uncovered struts of the 1st-SES and mural red thrombus. DAPT was continued thereafter, and 8 months later, follow-up CAG showed no significant RCA restenosis. To date, the patient remains free from cardiovascular events. This report documents a rare case of thrombotic occlusion of a 1st-SES with LSM, CAA, and stent fractures followed by non-invasive recanalization after clopidogrel treatment 15 years after 1st-SES implantation.

Learning objective

Stent thrombosis due to stent fracture and coronary aneurysm can occur even years after first-generation sirolimus-eluting stent (1st-SES) implantation. Risk assessment using coronary imaging should be made and long-term dual antiplatelet therapy (DAPT) should be recommended in patients with a high risk of stent thrombosis after 1st-SES implantation. In cases of stent thrombosis of the 1st-SES, resuming DAPT, including P2Y12 receptor inhibitors, may be a useful non-invasive treatment option.

Value of Absolute Eosinophil Count in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention

Background and Aims

Elevated eosinophils typically indicate hypersensitive inflammation; however, their involvement in cardiovascular events remains incompletely understood. We investigated the association between the absolute eosinophil count (AEC) and major adverse cardiovascular and cerebrovascular events (MACCEs) in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). Additionally, we determine whether the integration of AEC with the SYNTAX II score could improve predictive ability.

Methods and Results

The AECs of 1711 patients with ACS undergoing PCI from June 2016 to November 2017 were analyzed on admission. All recruitments were splitted into three groups based on AEC tertiles and 101 participants underwent one or more noteworthy outcomings. The association between AEC and MACCEs (defined as a composite of cardiovascular death, myocardial infarction [MI], and stroke) was tested by Cox proportional-hazards regression analysis. After adjusting for confounders, AEC was independently associated with MACCEs (HR 11.555, 95% CI: 3.318-40.239). Patients in the lowest AEC tertile (T1) as a reference, those in the higher tertiles had an incrementally higher risk of MACCEs (T3: HR 1.848 95% CI: 1.157-2.952; P for trend=0.008). Inclusion of AEC enhanced the predictive accuracy of the SYNTAX II score for MACCEs (AUC: from 0.701 [95% CI: 0.646-0.756] to 0.728 [95% CI: 0.677-0.780]; DeLong's test, P = 0.020).

Conclusion

AEC is independently linked to MACCEs in ACS patients who underwent PCI, and adds incremental predictive information to the SYNTAX II score.

Different drugs in drug-eluting stents for peripheral artery disease: a systematic evaluation and Bayesian meta-analysis

Drug-eluting stents (DESs) have become the first-line treatment for symptomatic peripheral arterial disease (PAD). Currently, there are many types of DESs on the market. The same type of DESs has different concentrations, and various drugs in them show uneven efficacy. The selection of DESs remains controversial. This study was aimed at comparing the long-term real-world outcomes of different DESs in the treatment of peripheral arterial occlusive disease (PAOD). The databases including Cochrane Library, Embase, and PubMed were searched with a time frame until March 25, 2023. The primary patency (PP) and target lesion revascularization (TLR) at 6 months were used as the primary endpoints. A total of 32 studies (5467 patients) were eligible. At the six-month follow-up, DES-Evero 1 ug/mm2 ranked first in terms of PP, with a significant difference from BMSs (RR [95% CI] = 1.6). DES-Siro 0.9 ug/mm2, DES-Siro 1.4 ug/mm2, DES-Siro 1.95 ug/mm2, DES-PTX 0.167 ug/mm2, DES-PTX 1 ug/mm2 and covered stents (CSs) showed significantly better PPs than BMSs. In terms of TLR, DES-Siro 0.9 ug/mm2 (0.31) ranked first, and DES-Evero 1 ug/mm2 ranked last. Among the treatment modalities for PAD, different DESs showed overall encouraging results in improving PP and TLR compared with BMSs. DES-Evero 1 ug/mm2 showed the best PP, but it had the highest reintervention rate at 6 months. Sirolimus-eluting stents were not always more effective with higher concentrations of sirolimus. Among various DESs, sirolimus-eluting stents and everolimus-eluting stents were superior to paclitaxel-eluting stents.

Methods for improving the properties of zinc for the application of biodegradable vascular stents

Biodegradable stents can support vessels for an extended period, maintain vascular patency, and progressively degrade once vascular remodeling is completed, thereby reducing the constraints of traditional metal stents. An ideal degradable stent must have good mechanical properties, degradation behavior, and biocompatibility. Zinc has become a new type of biodegradable metal after magnesium and iron, owing to its suitable degradation rate and good biocompatibility. However, zinc's poor strength and ductility make it unsuitable as a vascular stent material. Therefore, this paper reviewed the primary methods for improving the overall properties of zinc. By discussing the mechanical properties, degradation behavior, and biocompatibility of various improvement strategies, we found that alloying is the most common, simple, and effective method to improve mechanical properties. Deformation processing can further improve the mechanical properties by changing the microstructures of zinc alloys. Surface modification is an important means to improve the biological activity, blood compatibility and corrosion resistance of zinc alloys. Meanwhile, structural design can not only improve the mechanical properties of the vascular stents, but also endow the stents with special properties such as negative Poisson 's ratio. Manufacturing zinc alloys with excellent degradation properties, improved mechanical properties and strong biocompatibility and exploring their mechanism of interaction with the human body remain areas for future research.

Preliminary Investigation on Efficacy and Safety of Substance P-Coated Stent for Promoting Re-Endothelialization: A Porcine Coronary Artery Restenosis Model

BACKGROUND

Current polymer-based drug-eluting stents (DESs) have fundamental issues about inflammation and delayed re-endothelializaton of the vessel wall. Substance-P (SP), which plays an important role in inflammation and endothelial cells, has not yet been applied to coronary stents. Therefore, this study compares poly lactic-co-glycolic acid (PLGA)-based everolimus-eluting stents (PLGA-EESs) versus 2-methacryloyloxyethyl phosphorylcholine (MPC)-based SP-eluting stents (MPC-SPs) in in-vitro and in-vivo models.

METHODS

The morphology of the stent surface and peptide/drug release kinetics from stents were evaluated. The in-vitro proliferative effect of SP released from MPC-SP is evaluated using human umbilical vein endothelial cell. Finally, the safety and efficacy of the stent are evaluated after inserting it into a pig's coronary artery.

RESULTS

Similar to PLGA-EES, MPC-SP had a uniform surface morphology with very thin coating layer thickness (2.074 μm). MPC-SP showed sustained drug release of SP for over 2 weeks. Endothelial cell proliferation was significantly increased in groups treated with SP (n = 3) compared with the control (n = 3) and those with everolimus (n = 3) (SP: 118.9 ± 7.61% vs. everolimus: 64.3 ± 12.37% vs. the control: 100 ± 6.64%, p < 0.05). In the animal study, the percent stenosis was higher in MPC-SP group (n = 7) compared to PLGA-EES group (n = 7) (MPC-SP: 28.6 ± 10.7% vs. PLGA-EES: 16.7 ± 6.3%, p < 0.05). MPC-SP group showed, however, lower inflammation (MPC-SP: 0.3 ± 0.26 vs. PLGA-EES: 1.2 ± 0.48, p < 0.05) and fibrin deposition (MPC-SP: 1.0 ± 0.73 vs. PLGA-EES: 1.5 ± 0.59, p < 0.05) around the stent strut. MPC-SP showed more increased expression of cluster of differentiation 31, suggesting enhanced re-endothelialization.

CONCLUSION

Compared to PLGA-EES, MPC-SP demonstrated more decreased inflammation of the vascular wall and enhanced re-endothelialization and stent coverage. Hence, MPC-SP has the potential therapeutic benefits for the treatment of coronary artery disease by solving limitations of currently available DESs.

The relation of polymer structure of stent used in patients with acute coronary syndrome revascularized by stent implantation with long-term cardiovascular events

INTRODUCTION

Drug-eluting stents (DES) have revolutionized percutaneous coronary intervention (PCI) by improving event-free survival compared to older stent designs. However, early-generation DES with polymer matrixes have raised concerns regarding late stent thrombosis due to delayed vascular healing. To address these issues, biologically bioabsorbable polymer drug-eluting stents (BP-DES) and polymer-free drug-eluting stents (PF-DES) have been developed.

AIM

The aim of the present study is to evaluate and compare the long-term effects of different stent platforms in patients with acute coronary syndrome (ACS) undergoing PCI.

MATERIAL AND METHODS

We conducted a retrospective, observational study involving 1192 ACS patients who underwent urgent PCI. Patients were treated with thin- strut DP-DES, ultra-thin strut BP-DES, or thin-strut PF-DES. The primary endpoint was a composite of cardiac death, target vessel myocardial infarction (TVMI), and clinically driven target lesion revascularization (CITLR) at 12 months and 4 years.

RESULTS

The baseline demographics and clinical characteristics of patients in the three stent subgroups were similar. No significant differences were observed in target lesion failure (TLF), cardiac mortality, TVMI, and stent thrombosis (ST) rates among the three subgroups at both 12 months and 4 years. However, beyond the first year, the rate of CITLR was significantly lower in the ultra-thin strut BP-DES subgroup compared to thin-strut DP-DES, suggesting potential long-term advantages of ultra-thin strut BP-DES. Additionally, both ultra-thin strut BP-DES and thin-strut PF-DES demonstrated lower ST rates after the first year compared to thin-strut DP-DES.

CONCLUSION

Our study highlights the potential advantages of ultra-thin strut BP-DES in reducing CITLR rates in the long term, and both ultra-thin strut BP-DES and thin-strut PF-DES demonstrate lower rates of ST beyond the first year compared to thin-strut DP-DES. However, no significant differences were observed in overall TLF, cardiac mortality and TVMI rates among the three stent subgroups at both 12 months and 4 years.

Natural history of coronary stents: 14 year follow-up of drug eluting stents versus bare metal stents

BACKGROUND

Several randomized trials have shown the effectiveness of drug-eluting stents (DES) over bare metal stents (BMS) in terms of repeat revascularization at 1 year; however long term data in this context is conflicting.

AIM

To assess the long term clinical outcomes after coronary artery stenting with drug-eluting stents and bare metal stents.

METHODS

This is a retrospective cohort study, including 100 consecutive patients with Coronary Artery Disease who underwent successful percutaneous intervention (PCI) with implantation of DES and contemporary 100 patients who underwent PCI with implantation of BMS in the years 2005 and 2006 at our center.

RESULTS

Over a median follow-up of 14 years, the primary composite outcome of major adverse cardiovascular and cerebrovascular events (MACCE) was found to be similar in both the groups [DES-37; BMS-36 (p value = 0.88)]. At 1 year of follow-up, the incidence of MACCE was significantly lower with DES group than BMS group [DES-3; BMS-10, P value = 0.04]; but the benefit was not seen at 5 years, 10 years and 14 years follow-up. The incidence of very late stent thrombosis in our study population was similar in either of the groups (p value = 0.13). Obesity and creatinine of >1.4 mg/dl were found to be the predictors of all-cause death.

CONCLUSION

In patients with coronary artery disease, the composite endpoint of MACCE for the first year after stenting was significantly lower in patients receiving DES than those receiving BMS; however, at very long term follow-up, the event rates were similar.

Biodegradable or durable polymer drug-eluting stents in patients with coronary artery disease: ten-year outcomes of the randomised NEXT Trial

BACKGROUND

There are no randomised trials reporting clinical outcomes of biodegradable polymer biolimus-eluting stents (BP-BES) and durable polymer everolimus-eluting stents (DP-EES) at 10 years.

AIMS

We aimed to compare the 10-year clinical outcomes between BP-BES and DP-EES.

METHODS

The randomised NOBORI Biolimus-Eluting Versus XIENCE/PROMUS Everolimus-eluting Stent Trial (NEXT) was originally designed to evaluate the non-inferiority of BP-BES relative to DP-EES with the primary efficacy endpoint of target lesion revascularisation (TLR) at 1 year and the primary safety endpoint of death or myocardial infarction (MI) at 3 years. In this extended follow-up study, clinical outcomes were compared from 1 year after stent implantation up to 10 years between patients with BP-BES and DP-EES.

RESULTS

From May to October 2011, NEXT enrolled a total of 3,241 patients from 98 centres in Japan. The current study population consisted of 2,417 patients (1,204 patients with BP-BES and 1,213 with DP-EES) from 66 centres that agreed to participate in the extended study. Complete 10-year follow-up was achieved in 87.5% of patients. The cumulative 10-year incidence of death or MI was 34.0% in the BP-BES group and 33.1% in the DP-EES group (hazard ratio [HR] 1.04, 95% confidence interval [CI]: 0.90-1.20; p=0.58). TLR occurred in 15.9% of patients in the BP-BES group and in 14.1% of the DP-EES group (HR 1.12, 95% CI: 0.90-1.40; p=0.32). In a landmark analysis at 1 year, the cumulative incidences of death or MI and TLR were not significantly different between the 2 groups.

CONCLUSIONS

The safety and efficacy outcomes for BP-BES were not significantly different from those for DP-EES at 1 year and up to 10 years after stent implantation.

Selection criteria in the era of perfect competition for drug-eluting stents - a survey of interventional cardiologists in Japan: the selection-DES study

BACKGROUND

More than 20 years have passed since the first company introduced drug-eluting stent (DES) in 2002, but competing companies still have improved their DESs under regulatory approval. This study aimed to investigate the criteria for interventional cardiologists performing percutaneous coronary intervention (PCI) in selecting a DES.

RESEARCH DESIGN AND METHODS

From 10 April 2023, to 30 April 2023, 3,422 cardiologists were requested to complete a questionnaire, of whom 126 responded to the survey.

RESULTS

Overall, 86.5% of the respondents used Xience cobalt-chromium everolimus-eluting stent (Xience) in > 10% of PCI procedures. For Xience, brand loyalty and calcified lesions were important independent variables for the DES selection criteria. Ultimaster sirolimus-eluting stent (Ultimaster) was not affected by the clinical data delivered by the company, whereas the respondents were shown to seek support for their activities from the Ultimaster supplier. The relationship with the company and/or sales representative and the planned surgical procedure affected the use of Coroflex ISAR NEO sirolimus-eluting polymer-free stent.

CONCLUSIONS

Patient background and lesion characteristics had little impact on the DES selection criteria, suggesting that DES performance has already reached its physical limitations to the extent that respondents may not value further improvements in performance or characteristics of DES.

Restoring endothelial function: shedding light on cardiovascular stent development

Complete endothelialization is highly important for maintaining long-term patency and avoiding subsequent complications in implanting cardiovascular stents. It not only refers to endothelial cells (ECs) fully covering the inserted stents, but also includes the newly formed endothelium, which could exert physiological functions, such as anti-thrombosis and anti-stenosis. Clinical outcomes have indicated that endothelial dysfunction, especially the insufficiency of antithrombotic and barrier functions, is responsible for stent failure. Learning from vascular pathophysiology, endothelial dysfunction on stents is closely linked to the microenvironment of ECs. Evidence points to inflammatory responses, oxidative stress, altered hemodynamic shear stress, and impaired endothelial barrier affecting the normal growth of ECs, which are the four major causes of endothelial dysfunction. The related molecular mechanisms and efforts dedicated to improving the endothelial function are emphasized in this review. From the perspective of endothelial function, the design principles, advantages, and disadvantages behind current stents are introduced to enlighten the development of new-generation stents, aiming to offer new alternatives for restoring endothelial function.

Dynamic investigation of zein-based degradable and hemocompatible coatings for drug-eluting stents: a microfluidic approach

Biodegradable stent coatings have shown great potential in terms of delivering drugs to a damaged vessel wall, and their release profiles are key elements governing the overall performance of drug-eluting stents (DESs). However, release and degradation kinetics are usually not tested under simulated physiological conditions or in dynamic environments, both essential aspects in the design of novel DESs. To bridge this gap, fused silica-based microfluidic systems, with either round or square channel cross-sections, were designed to mimic the microenvironment of a stented vessel. In particular, we fabricated and characterized microfluidic chips based on customizable channels, which were spray-coated with a naturally-derived, rutin-loaded zein solution, to perform a comprehensive study under flow conditions. Dynamic assays after 6 hours showed how the degradation of the zein matrix was affected by the cross-sectional conformation (∼69% vs. ∼61%, square and round channel, respectively) and the simulated blood fluid components (∼55%, round channel with a more viscous solution). The released amount of rutin was ∼81% vs. ∼77% and ∼78% vs. ∼74% from the square and round channels, using the less and more viscous blood-simulated fluids, respectively. Fitting the drug release data to Korsmeyer-Peppas and first-order mathematical models provided further insight into the mechanism of rutin release and coating behavior under flowing conditions. More importantly, whole blood tests with our newly developed microfluidic platforms confirmed the hemocompatibility of our zein-based coating. In detail, in-flow and static studies on the blood cell behavior showed a significant reduction of platelet adhesion (∼73%) and activation (∼93%) compared to the stainless-steel substrate, confirming the benefits of using such naturally-derived coatings to avoid clogging. Overall, our microfluidic designs can provide a key practical tool for assessing polymer degradation and drug release from degradable matrices under flowing conditions, thus aiding future studies on the development of hemocompatible, controlled-release coatings for DESs.

A novel polymer-free everolimus-eluting stent with a nitrogen-doped titanium dioxide film inhibits restenosis and thrombosis in a swine coronary model

BACKGROUND

Short-term outcomes regarding the safety and efficacy of a polymer-free everolimus-eluting stent (EES) with a nitrogen-doped titanium dioxide (N-TiO₂) film in a swine coronary model have been reported. However, the long-term results of the use of this type of stent have not yet been evaluated or compared to those of other polymer-free coronary stents. Therefore, this study aimed to determine the mid- to long-term safety and efficacy of a polymer-free EES with an N-TiO₂ film in a swine coronary model.

METHODS

Polymer-free EES with N-TiO₂ films (n = 30) and polymer-free sirolimus-eluting stents (SES; n = 30) were implanted in 30 pigs. Quantitative coronary analysis and optical coherence tomography were conducted immediately and at 1 (quantitative coronary analysis only), 3, and 6 months after stenting. Histopathologic examinations were performed at 1, 3, and 6 months after stenting.

RESULTS

The polymer-free EES group had a lower percentage of neointimal growth than the polymer-free SES group at 3 months (22.5% ± 11.4% vs. 32.1% ± 12.3%; p < 0.001). The polymer-free EES group had a lower fibrin score than the polymer-free SES group at 1 month (1.9 ± 0.45 vs. 2.5 ± 0.54; p = 0.001). The re-endothelialization rates were similar between groups. The polymer-free EES group had a lower percentage of the area of stenosis than the polymer-free SES group throughout the follow-up period.

CONCLUSIONS

The novel polymer-free EES with an N-TiO₂ film has superior safety and efficacy than the polymer-free SES at the 6-month follow-up in a swine model.

The Outcome of Ultrathin-Strut Biodegradable Polymer-Coated Sirolimus-Eluting Stents in Coronary Artery Disease Patients - A Feasibility Study

Background

Drug-eluting coronary stents with ultrathin struts and biodegradable polymers have been shown to reduce inflammation, neointimal proliferation, and thrombus formation, leading to less early and late complications in patients with coronary artery disease as compared to thinner strut and durable polymer second-generation stents. In Oman, currently, second-generation stents are used for all patients.

Objective

The purpose of this feasibility study was to evaluate the clinical safety and performance of ultrathin-strut (60 μm) biodegradable polymer-coated sirolimus-eluting stents in an all-comers patient population.

Methods

This was a prospective, observational, single-center, and single-arm investigator-initiated study from August 2018 to August 2019. Inclusion criteria: 18 years of age, patients with symptomatic coronary artery disease indicated for percutaneous coronary intervention, and stenting of at least one coronary lesion. All patients were followed clinically or telephonically at 12 months after the index procedure.

Results

A total of 88 patients were recruited in the study, but 10 patients were lost to follow-up and hence excluded from the analysis. The overall mean age was 63 ± 13 years and 78% were males. The main comorbid conditions were hypertension (58%), diabetes mellitus (49%), and hyperlipidemia (26%). Fifty-three percent presented with unstable angina or non-ST elevation myocardial infarction (MI), 10% with ST elevation MI, recent MI 16%, 18% with stable angina, and 1.3% in cardiogenic shock. The mean left ventricular ejection fraction of the cohort was 46 ± 14%. Angiographically, Type A lesions were seen in 25%, Type B in 32%, and Type C in 42%. Left anterior descending stenting was done in 44%, right coronary artery in 32%, left circumflex artery in 14%, left main in 5%, and graft stenting in 4%. Device success was 96%. Procedural success was seen in 97% of patients. At 1-year follow-up, 93% were asymptomatic; overall device-oriented clinical events were 6.8% including cardiac death in 2.7%, target-vessel MI in 2.7%, and target-lesion revascularization in 1.3% which all occurred in uncontrolled diabetic patients.

Conclusions

At index admission and 1 year, ultrathin-strut biodegradable polymer-coated sirolimus-eluting stent study showed low device-related adverse clinical events which are comparable to published data for the second-generation stents. This feasibility study shows that these stents can be used in all types of stent-indicated patients with added advantages of biodegradable polymer and ultrathin struts. In addition, measures to prevent, diagnose, and control diabetes need to be taken in Oman as this cohort of patients develop ST after stenting.

Pathologic characteristics of human venous in-stent stenosis and stent occlusion

OBJECTIVE

The objective of this study was to determine the pathologic features of venous in-stent stenosis over time occurring in bare metal stents.

METHODS

Endovascular biopsy samples were obtained prospectively from venous bare metal stents implanted in 2009 through 2018. All samples were formalin-fixed, paraffin-embedded and stained with hematoxylin and eosin. Samples were examined by a cardiovascular pathologist to estimate the amount of its constituent components, which included fresh thrombus, organizing thrombus, old thrombus, or diffuse intimal thickening (DIT), and pathologic features including calcification, neovascularization, and hemosiderin deposition. This pathologic characterization was correlated with time following stent implantation to discern time-dependence of pathologic evolution of in-stent stenosis using both descriptive statistics and binary logistic regression.

RESULTS

A total of 254 post-stent venograms with biopsies of in-stent contents from 148 unique patients were studied. Fresh thrombus and organizing thrombus were both present across all studied time intervals. Old thrombus was seen beginning at approximately 2 weeks and DIT at approximately 4 weeks. Calcification was a rare finding encountered at later time intervals. The prevalence of each component varied with time: the probability of encountering fresh thrombus (P = .010) and organizing thrombus (P = .008) decreased over time. By contrast, the probability of finding DIT (P = .002) and calcifications (P < .001) increased over time. The presence of old thrombus, neovascularization, or hemosiderin did not demonstrate time dependence. Diffuse intimal thickening was frequently seen along with organizing thrombus as well as independently, and in many instances, these two features were directly merged.

CONCLUSIONS

The evolution of human venous in-stent restenosis appears to follow a time-dependent course, suggesting a possible progressive evolution from fresh and organizing thrombus to DIT. Contrasted with the literature on arterial in-stent restenosis, vein in-stent restenosis may have an increased thrombus prevalence (both organizing and old thrombus). DIT is a primary feature of late in-stent stenosis and may explain in part why many of these lesions may not respond to thrombolytic or anticoagulant treatment alone.

Polymer Free Amphilimus Drug Eluting Stent for Infrapopliteal Arterial Disease in Patients with Critical Limb Ischemia: A New Device in the Armamentarium

Background and Objectives: Endovascular technologies have significantly improved the outcome of patients with critical limb ischemia (CLI). Drug eluting stents (DES) have documented their efficacy against percutaneous transluminal angioplasty (PTA) and bare metal stents (BMS) in infrapopliteal arterial occlusive disease. However, late in-stent neoatherosclerosis may lead to vascular lumen loss and eventually thrombosis. Polymer free DES constitute a new technology aiming to improve long term patency which their action is still under investigation. The purpose of this study is to report the mechanism of action and to provide a literature review of a novel polymer free amphilimus eluting stent (Cre8, Alvimedica, Instabul, Turkey) in infrapopliteal arterial disease. Methods: Publications listed in electronic databases, European Union Drug Regulating Authorities Clinical Trials Database, as well as scientific programmes of recent interventional vascular conferences were searched. Three studies were included. We analyzed primary and secondary patency, major amputation rate, freedom from CD-TLR, and mortality. Results: Cre8 was implanted in 79 patients with CLI. Most of the patients (n = 65) were Rutherford class 5-6 (82.3%), and diabetes mellitus (DM) was present in 66 patients (83.5%). Mean primary patency was 82.5% at 12 months. Mean lesion stented length was 20 mm and 35 mm in two studies. Mean limb salvage was 91.3% at 12 months. Freedom from CD-TLR was reported in two out of the three studies and was 96% and 83.8%. Mortality was 15% and 23.8% in the same studies, whilst it was not reported in one study. Conclusion: Stenting of infrapopliteal arteries with Cre8 is safe and feasible in patients with CLI and diabetes. All studies have shown very good primary patency and freedom from CD-TLR at 12 and 24 months. Larger observational prospective studies and randomized trials are necessary to establish long term effectiveness and clinical outcomes using the non-polymer Cre8 DES.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Optimal Antithrombotic Therapy in Patients Undergoing Percutaneous Coronary Intervention: A Focused Review on High Bleeding Risk

Dual antiplatelet therapy (DAPT) is a therapeutic cornerstone to prevent stent thrombosis following percutaneous coronary intervention (PCI) for coronary artery disease (CAD). However, the longer the DAPT duration, the higher the incidence of bleeding and mortality. Since the advent of second-generation drug-eluting stents (DES), the continuous evolution of DES has reduced the thrombotic risk and allowed for a shorter DAPT duration. On the other hand, concerns on the elevated risk of bleeding during antithrombotic therapy have been further raised due to the growing number of elderly CAD patients with multiple comorbidities. The consequent debate topic over post-PCI antithrombotic therapy has shifted from simply reducing thrombotic risk to safely minimizing bleeding risk. Due to the significant impact of bleeding on clinical outcomes, including prognosis, current guidelines on antithrombotic therapy for CAD prioritize stratification of patients at a high bleeding risk (HBR) as the top consideration in determining post-PCI antithrombotic therapy. Achieving optimal antithrombotic therapy for each patient undergoing PCI requires a better understanding of the clinical variables constituting the balance of bleeding and thrombotic risk. This review highlights relevant evidence required to optimize antithrombotic therapy for HBR patients undergoing PCI.

Hypersensitivity and in-stent restenosis in coronary stent materials

Coronary heart disease (CHD) is a type of cardiovascular disease with the highest mortality rate worldwide. Percutaneous transluminal coronary intervention (PCI) is the most effective method for treating CHD. However, in-stent restenosis (ISR), a long-term complication after PCI, affects the prognosis of patients with CHD. Previous studies have suggested that hypersensitivity reactions induced by metallic components may be one of the reasons of this complication. With the emergence of first- and second-generation drug-eluting stents (DES), the efficacy and prognosis of patients with CHD have greatly improved, and the incidence of ISR has gradually decreased to less than 10%. Nevertheless, DES components have been reported to induce hypersensitivity reactions, either individually or synergistically, and cause local inflammation and neointima formation, leading to long-term adverse cardiovascular events. In this article, we described the relationship between ISR and hypersensitivity from different perspectives, including its possible pathogenesis, and discussed their potential influencing factors and clinical significance.

Does the use of polymer-free drug eluting stents improve clinical outcomes of patients undergoing percutaneous coronary interventions?

BACKGROUND

Implantation of drug eluting stents (DES) is the mainstay treatment for patients requiring percutaneous coronary intervention (PCI). The polymer coating of DES has been associated with inflammatory response, increased arterial injury and long-term in-stent restenosis and thrombosis. Polymer-free stents (PFS) were designed to overcome limitations of polymer-coated stents (PCS). Our aim was to compare clinical outcomes of patients undergoing PCI with PFS versus contemporary PCS.

METHODS

This is a prospective, open-label registry study enrolling consecutive all-comers patients admitted to a single center and undergoing PCI using contemporary DES. Clinical outcomes were compared between patients treated with PFS and PCS. The primary endpoint was target lesion revascularization (TLR) at 12 months. Subgroup analyses were conducted for diabetic and nondiabetic patients.

RESULTS

Overall, 1664 patients were included: 928 (55.8%) of which were treated with PFS and 736 (44.2%) with PCS for 2046 and 1462 lesions, respectively. At 12 months, TLR rates were not significantly different between the groups (1.7% vs. 2.3% for PFS and PCS, respectively, P = 0.48). The use of PFS did not improve clinical outcomes among diabetic patients in comparison with PCS. Target vessel revascularization and major adverse cardiac events rates were also similar between groups, regardless of diabetes status.

CONCLUSION

Newer generation DES offer excellent results in diabetic and nondiabetic patients without significant differences in outcomes between PCS and PFS.

Polymer–Metal Composite Healthcare Materials: From Nano to Device Scale

Metals have been investigated as biomaterials for a wide range of medical applications. At nanoscale, some metals, such as gold nanoparticles, exhibit plasmonics, which have motivated researchers’ focus on biosensor development. At the device level, some metals, such as titanium, exhibit good physical properties, which could allow them to act as biomedical implants for physical support. Despite these attractive features, the non-specific delivery of metallic nanoparticles and poor tissue–device compatibility have greatly limited their performance. This review aims to illustrate the interplay between polymers and metals, and to highlight the pivotal role of polymer–metal composite/nanocomposite healthcare materials in different biomedical applications. Here, we revisit the recent plasmonic engineered platforms for biomolecules detection in cell-free samples and highlight updated nanocomposite design for (1) intracellular RNA detection, (2) photothermal therapy, and (3) nanomedicine for neurodegenerative diseases, as selected significant live cell–interactive biomedical applications. At the device scale, the rational design of polymer–metallic medical devices is of importance for dental and cardiovascular implantation to overcome the poor physical load transfer between tissues and devices, as well as implant compatibility under a dynamic fluidic environment, respectively. Finally, we conclude the treatment of these innovative polymer–metal biomedical composite designs and provide a future perspective on the aforementioned research areas.

Evolution of drug-eluting coronary stents: a back-and-forth journey from the bench-to-bedside

Coronary stents have revolutionized the treatment of coronary artery disease. Compared with balloon angioplasty, bare-metal stents effectively prevented abrupt vessel closure but were limited by in-stent restenosis due to smooth muscle cell proliferation and neointimal hyperplasia. The first-generation drug-eluting stent (DES), with its antiproliferative drug coating, offered substantial advantages over bare-metal stents as it mitigated the risk of in-stent restenosis. Nonetheless, they had several design limitations that increased the risk of late stent thrombosis. Significant advances in stent design, including thinner struts, enhanced polymers' formulation, and more potent antiproliferative agents, have led to the introduction of new-generation DES with a superior safety profile. Cardiologists have over 20 different DES types to choose from, each with its unique features and characteristics. This review highlights the evolution of stent design and summarizes the clinical data on the different stent types. We conclude by discussing the clinical implications of stent design in high-risk subsets of patients.

Early vascular healing of ultra-thin strut polymer-free sirolimus-eluting stents in acute coronary syndrome: USUI-ACS study

Ultra-thin strut polymer-free sirolimus-eluting stent (UPF-SES) have two novel characteristics, ultra-thin strut and polymer-free coating, which have the potential to achieve early re-endotherialization. However, a little is known whether early vascular healing of UPF-SES can be achieved in patients with acute coronary syndrome (ACS). The aim of this study was to evaluate the vascular healing after an implantation of UPF-SES in patients with ACS using optical coherence tomography (OCT) at 3 months after the stent implantation. From September 2020 and January 2021, a total of 31 consecutive patients presenting with ACS who underwent OCT-guided percutaneous coronary intervention (PCI) and 3 month follow-up OCT examination were enrolled in the USUI-ACS study. The endpoints of this study were neointimal strut coverage, malapposition, and mean neointimal hyperplasia (NIH) thickness at 3 month follow-up. Over a mean follow-up of 91 days after the initial PCI, the follow-up OCT was examined. The median percentage of covered struts was 98.4% and malapposed struts 0%, and the mean NIH thickness was 80 μm. UPF-SES exhibited an excellent early vascular healing at 3 months in patients with ACS.

Very Late Stent Thrombosis after Discontinuation of Antiplatelet Agents during Anticoagulation Therapy in a Patient with Peri-stent Contrast Staining after Implantation of a Second-generation Drug-eluting Stent

A 54-year-old man was admitted to our hospital due to intermittent chest pain. He had a history of acute myocardial infarction, and peri-stent contrast staining had been observed at the stent implantation site. The patient previously underwent anticoagulation therapy for left ventricular thrombus and antiplatelet therapy to prevent stent thrombosis. More than one year after implantation of a drug-eluting stent, antiplatelet drugs were discontinued, and anticoagulant alone was prescribed according to the guidelines, which resulted in very late stent thrombosis. The risks of both bleeding and thrombosis must be fully considered when deciding whether or not to discontinue antiplatelet therapy during anticoagulation therapy.

pH-Responsive Nanoparticles for Delivery of Paclitaxel to the Injury Site for Inhibiting Vascular Restenosis

A high incidence of restenosis has been reported at the site of inflammation following angioplasty and stent implantation. The anti-proliferative drug paclitaxel (PTX) could help to reduce inflammation and restenosis; however, it has poor water solubility and serious adverse side effects at high doses. Given the presence of metabolic acidosis at the site of inflammation, we hypothesized that nanoparticles that are responsive to low pH could precisely release the loaded drug at the target site. We successfully constructed pH-responsive poly(D, L-lactic-co-glycolic acid) (PLGA) nanoparticles loaded with PTX and NaHCO3 as a pH-sensitive therapeutic agent (PTX-NaHCO3-PLGA NPs). The NPs exhibited remarkable pH sensitivity and a good safety profile both in vitro in rat vascular smooth muscle cells and in vivo in Sprague Dawley rats after tail vein injection. In the rat model, the PTX-NaHCO3-PLGA NPs treatment group showed suppressed intimal proliferation following balloon-induced carotid artery injury compared with that of the saline-treated control. Overall, these results demonstrate that our newly developed pH-responsive nanodrug delivery platform has the potential to effectively inhibit restenosis.

Drug-eluting stents for the treatment of coronary artery disease: A review of recent advances

INTRODUCTION

Percutaneous coronary intervention is a widely used procedure for the treatment of coronary artery disease to relieve narrowing or occlusion and improve blood supply. Although only balloon angioplasty was performed in the early period, coronary stents were developed later and coronary drug-eluting stents were introduced to decrease in-stent restenosis, which is related to the proliferation and migration of vascular smooth muscle cells.

AREAS COVERED

The drug-eluting stents are composed of a metallic or polymeric platform, specific drug, and polymers or coating for drug release. In this article, the recent advances in drug-eluting stent technologies for the treatment of coronary artery disease and adjunctive antiplatelet therapy after drug-eluting stent implantation will be reviewed.

EXPERT OPINION

The need for further advances in drug-eluting stents or fully bioresorbable coronary scaffolds still exists to improve patient survival or clinical outcomes. The use for different actions or of combinations of drugs with several actions can be potential. Technological refinement and progress in manufacturing to improve mechanical integrity are needed, particularly for fully bioresorbable scaffolds. For antiplatelet therapy after stenting, clinical bleeding reduction strategies, such as a shortened duration of dual-antiplatelet therapy, are in progress.

Case series of coronary artery aneurysms after Everolimus eluting stent implantation and comparison with Sirolimus eluting stents

Background

Coronary artery aneurysms after drug eluting stents are rare. We present a case series of type II coronary aneurysms after implantation of Everolimus eluting stents including patients developing giant aneurysms with a toxic course.

Case presentation

Over a span of 3.5 years at our center 2572 patients were implanted Everolimus eluting stents out of which 4 patients developed coronary type II aneurysms an incidence of 0.00156 whereas 5838 patients were implanted Sirolimus eluting 2nd generation stents out of which 2 patients developed similar aneurysms with an incidence of 0.00034. The slight increase in incidence in Everolimus stents does not reach statistical significance (p = 0.054) and is limited by single centre non randomized study. We also propose a hypothesis that the slight increase in the incidence maybe due to allergy to Methacrylate present in Everolimus eluting Xience stent’s primer which is absent in other Sirolimus eluting stents used at our center but that needs to be further investigated. We also found some patients who developed giant aneurysms including Left main aneurysms. In our series operative repair of these patients had better outcomes than covered stent deployment but larger trials maybe needed to confirm the same.

Conclusions

Coronary artery aneurysms after stent implantation are rare but occasionally giant aneurysms are formed with a toxic course. The incidence and morphology of aneurysms after Everolimus and Sirolimus eluting stent deployment do not differ much.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02503-1.

A Review on Manufacturing and Post-Processing Technology of Vascular Stents

Percutaneous coronary intervention (PCI) with stent implantation is one of the most effective treatments for cardiovascular diseases (CVDs). However, there are still many complications after stent implantation. As a medical device with a complex structure and small size, the manufacture and post-processing technology greatly impact the mechanical and medical performances of stents. In this paper, the development history, material, manufacturing method, and post-processing technology of vascular stents are introduced. In particular, this paper focuses on the existing manufacturing technology and post-processing technology of vascular stents and the impact of these technologies on stent performance is described and discussed. Moreover, the future development of vascular stent manufacturing technology will be prospected and proposed.

Simultaneous Multi-Vessel Very Late Stent Thrombosis in Acute ST-Segment Elevation Myocardial Infarction

Simultaneous multi-vessel very later stent thrombosis (VLST) is a very rare complication of percutaneous coronary intervention (PCI). We present a case of simultaneous multi-vessel VLST as the cause of acute ST-segment elevation myocardial infarction (STEMI). PCI of the culprit vessel was performed at acute presentation. Resolution of in-stent thrombosis in non-culprit vessels was noted on coronary angiography 2 days later. Our case suggests that PCI for culprit lesion in acute setting may be a reasonable option for simultaneous multi-vessel VLST.

How Does Fluid Flow Influence Drug Release from Drug Filled Implants?

Drug-filled implants (DFIs) have emerged as an innovative approach to control the delivery of drugs. These devices contain the drug within the structure of the implant itself and avoid the need to include additional drug carrier materials such as a polymers, which are often associated with inflammation and delayed healing/tissue regeneration at the implant site. One common feature of in vitro experiments to generate drug release profiles is stirring or agitation of the release medium. However, the influence of the resulting fluid flow on the rate of drug release from DFIs has yet to be quantified. In this paper we consider two DFIs, which although similar in shape and size, employ different strategies to control the release of drug: a porous pin with pores on the order of μm and a pin drilled with orifices of the order of mm. We develop a multiphysics mathematical model of drug release from these DFIs, subject to fluid flow induced through stirring and show that fluid flow greatly influences the drug release profile for the orifice pin, but that the porous pin drug release profile is relatively insensitive to flow. We demonstrate that drug release from the porous pin may adequately be described through a simplified radial 1D dissolution-diffusion model, while a 3D dissolution-advection-diffusion model is required to describe drug release from the orifice pin. A sensitivity analysis reveals that that the balance of reaction-advection-diffusion in terms of key nondimensional numbers governs the overall drug release. Our findings potentially have important implications in terms of devising the most relevant experimental protocol for quantifying drug release from DFIs.

Incidence and natural history of coronary evagination after implanted biodegradable polymer sirolimus-eluting stent

Aims

The incidence and temporal change in coronary evagination (CE) after first-generation drug-eluting stent implantation is well established, whereas that after biodegradable polymer sirolimus-eluting stent (BP-SES) implantation has not yet been evaluated. The aim of this study is to assess the incidence and natural history of CE after BP-SES implantation.

Methods and results

In this multicenter registry, stable coronary lesions treated by Ultimaster BP-SES were evaluated by serial optical frequency domain imaging (OFDI) (at 0-1-12 or 0-3-12 months) and the incidence of CE was assessed. Coronary evagination was defined as the presence of an outward bulge in luminal vessel contour between apposed struts according to the following criteria: (i) evagination depth ≥10% of nominal stent diameter and (ii) evagination length ≥3.0 mm. Optical frequency domain imaging was obtained in 98, 47, 49, and 87 lesions at 0, 1, 3, and 12 months, respectively. Coronary evagination was observed in 20 (42.6%) and 12 (24.5%) lesions at 1 and 3 months, respectively, and all but one CE had resolved at 12 months. At 12 months, the mean CE area was almost zero and the mean malapposed stent area was also decreased. Comparison of the serial OFDI images indicated that CEs originated mostly from acute stent malapposition or coronary dissection behind the implanted stent.

Conclusions

In stable lesions, CE was occasionally observed with Ultimaster BP-SES at 1-3 months but mostly resolved within 12 months, without late-acquired stent malapposition. These findings suggest the safety and feasibility of biodegradable polymer coating on DES.

Overcoming challenges in refining the current generation of coronary stents

INTRODUCTION

Late stent thrombosis caused by delayed vascular healing and prolonged local inflammation were major drawbacks of 1^st generation drug-eluting stents (DES). Strut design, biocompatibility of polymer, and drug-release profiles were improved in 2^nd and 3rdgeneration DES. Accordingly, the indications for percutaneous coronary intervention with DES have been expanded to more complex patients and lesions. Despite these improvements, significant barriers such as greater flexibility in the duration of dual-antiplatelet therapy (DAPT) as well as reducing long-term stent-related events remain. To achieve ideal short- and long-term results, these existing limitations need to be overcome.

AREAS COVERED

We will discuss the current limitations of coronary DES and how they might be overcome from pathological and clinical viewpoints.

EXPERT OPINION

Optimizing DAPT duration after stent implantation and prevention of in-stent neoatherosclerosis are two major issues in current DES. Overcoming these drawbacks is a prerequisite toward achieving better short- and long-term clinical outcomes. New technologies including platform design, polymer types, and anti-proliferative agent itself might lead to further improvements. Although the initial experience with bioresorbable scaffold/stents (BRS) was disappointing, positive results of clinical studies regarding novel BRS are raising expectations. Overall, further device innovation is desired for overcoming the limitations of current DES.

3-Year Clinical Outcomes After Implantation of Permanent-Polymer Versus Polymer-Free Stent: ReCre8 Landmark Analysis

OBJECTIVES

The aim of this analysis was to assess long-term clinical outcomes of the polymer-free Amphilimus-eluting stent (PF-AES) compared with a latest generation permanent-polymer drug-eluting stent (DES) in an all-comers population.

BACKGROUND

PF-AES possess multiple properties improving targeted drug elution without the presence of polymers. Evaluation of long-term clinical performance of PF-AES versus latest generation permanent-polymer DES has not yet been performed in a large randomized trial introducing shortened dual-antiplatelet therapy.

METHODS

In this physician-initiated, multicenter, randomized, all-comers trial, patients undergoing percutaneous coronary intervention with implantation of DES were enrolled. Patients were stratified for diabetes and troponin status and randomized to implantation of a permanent-polymer zotarolimus-eluting stent (PP-ZES) or a PF-AES. Dual-antiplatelet therapy duration was 12 months in troponin-positive patients and 1 month in troponin-negative patients. A noninferiority analysis was conducted to compare the 2 arms regarding target lesion failure (TLF) between 1 and 3 years.

RESULTS

A total of 1,491 patients were randomized and treated. In this landmark analysis, between 1- and 3-year follow-up, TLF occurred in 35 patients (4.9%) in the PP-ZES arm and 37 PF-AES patients (5.1%). Clinical noninferiority of the PF-AES was confirmed, with a risk difference of 0.2% (upper limit 1-sided 95% CI: 2.2%; P_{noninferiority} = 0.0031).

CONCLUSIONS

ReCre8 (Randomized "All-Comer" Evaluation of a Permanent Polymer Resolute Integrity Stent Versus a Polymer Free Cre8 Stent) is the first randomized, multicenter trial with a head-to-head comparison of PP-ZES compared with PF-AES to investigate clinical outcomes of these new-generation DES in an all-comers population with long-term follow-up. On the basis of the present results, PF-AES are clinically noninferior to PP-ZES regarding TLF between 1 and 3 years. (Randomized "All-Comer" Evaluation of a Permanent Polymer Resolute Integrity Stent Versus a Polymer Free Cre8 Stent; NCT02328898).

Real-World Clinical Outcomes of Indigenous Biodegradable Polymer Drug-Eluting Stents

Introduction

The durable polymer has been shown to cause neoatherosclerosis, and chronic local inflammation, predisposing individuals to in-stent restenosis and stent thrombosis (ST). The biodegradable polymer stents, which degrade after the desired function of drug release is achieved, allow for endothelial healing. Indigenous coronary stent manufacturing and its use are on the rise nowadays, and their safety and efficacy have been studied in well-structured clinical trials. However, data are scarce on their safety and efficacy in the real-world clinical setting. In this study, we examine the real-world one-year performance of bioresorbable or polymer-free stents manufactured in India.

Materials and methods

This was a single-center, single-arm prospective observational study involving 210 patients undergoing intracoronary stenting using bioabsorbable or polymer-free drug-eluting stents (DES) from Indian manufacturers. All patients were followed up for 12 months prospectively for any major clinical events.

Results

The mean age of the enrolled patients was 57.04 years (IQR: 34-84 years), among which 159 (75.7%) were male; 99 (43.8%) patients had presented with acute myocardial infarction (MI). A total of 294 stents were deployed with a mean diameter of 3.1 ±0.4 mm, and a mean length of 29.4 ±9.1 mm. Two patients had experienced major adverse cardiovascular events (MACE). After three months of follow-up, one patient developed ST, and the same patient developed a cerebrovascular accident (CVA) after six months. After one year of follow-up, one patient died of cardiac causes.

Conclusion

Based on our findings, in the real-world clinical setting, the indigenously made biodegradable polymer DES are both safe and effective.

COBRA PzF™ coronary stent in clinical and preclinical studies: setting the stage for new antithrombotic strategies?

Major advances have been made in coronary artery stent technology over the last decades. Drug-eluting stents reduced in-stent restenosis and have shown better outcomes compared with bare metal stents, yet some limitations still exist to their use. Because they delay healing of the vessel wall, longer dual antiplatelet therapy is mandatory to mitigate against stent thrombosis and this limitation is most concerning in subjects at high risk for bleeding. The COBRA PzF nanocoated coronary stent has been associated with accelerated endothelialization relative to drug-eluting stents, reduced inflammation and thromboresistance in preclinical studies, suggesting more flexible dual antiplatelet therapy requirement with potential benefits especially in those at high bleeding risk. Here, we discuss the significance of COBRA PzF in light of recent experimental and clinical studies.

Comparison of long-term clinical outcomes among zotarolimus-, everolimus-, and biolimus-eluting stents in acute myocardial infarction patients with renal impairment

BACKGROUND

It is important to determine the best drug-eluting stent (DES) for acute myocardial infarction (AMI) in patients with renal impairment. In this studythe outcomes of everolimus-eluting stents (EESs), zotarolimus-eluting stents (ZESs) and biolimus-eluting stents (BESs) were evaluated.

METHODS

From the Korea Acute Myocardial Infarction-National Institutes of Health registry, a total of 1,470 AMI patients with renal impairment undergoing percutaneous coronary intervention (PCI) were enrolled (816 with EES, 345 with ZES, and 309 with BES). Renal impairment was defined as creatinine clearance < 60 mL/min/1.73 m² estimated by the Cockcroft-Gault method. Major adverse cardiac and cerebrovascular events were determined as the composite of all-cause death, non-fatal myocardial infarction (MI), cerebrovascular accident, any revascularization, rehospitalization and stent thrombosis. All clinical outcomes were analyzed.

RESULTS

The baseline characteristics of the patients revealed no significant difference between the three groups, except for Killip classification > 2, beta-blockers, lesion type, vascular approach, staged PCI, left main coronary artery (LMCA) complex lesions, LMCA PCI, and the number and length of implanted stents. In the Kaplan-Meier analysis, similar clinical outcomes were derived from the unadjusted data between the three DES groups. However, after the inverse probability of treatment weighting, a statistically significant difference was found in non-fatal MI, which implied a higher incidence of non-fatal MI in the ZES group than in the other two DES groups.

CONCLUSIONS

In AMI patients with renal impairment, there was no significant difference between the three stent groups in terms of long-term clinical outcomes, except for non-fatal MI.

Some Perspectives on Hypersensitivity to Coronary Stents

The development of coronary stents has represented a revolution in the treatment of coronary heart disease. Beyond their many advantages, stents also have their limitations and complications. Allergic reactions to coronary stents are more common than acknowledged. These stented patients are exposed to foreign substances inserted in direct contact with the coronary intima. Hypersensitivity to stent components and drugs prescribed after stent insertion together with any environmental exposure seem to contribute to these adverse reactions. Patients can present to the hospital with a wide range of symptoms and multiple complications, the most important ones being instent restenosis and stent thrombosis. Although not very common (and not always easy to identify), allergic reactions after coronary or peripheral stents should be taken into account. Careful selection of patients (for elective stent implantation) depending on the propensity to allergies, although hard to achieve, represents a key factor in reducing the number of these complications.

Target Lesion Failure With Current Drug-Eluting Stents: Evidence From a Comprehensive Network Meta-Analysis

OBJECTIVES

The aim of this study was to investigate the efficacy and safety of currently used drug-eluting stents (DES).

BACKGROUND

Head-to-head comparisons among newer DES have shown conflicting results.

METHODS

For this network meta-analysis, randomized controlled trials comparing different types of currently used DES were searched in PubMed, Scopus, and proceedings of international meetings. The primary endpoint was target lesion failure (TLF) at 1 year and at long-term follow-up.

RESULTS

Seventy-seven trials with 99,039 patients were selected for this network meta-analysis. Among the 10 DES included in the meta-analysis, 4 received the most extensive investigation: Orsiro, XIENCE, Nobori/BioMatrix, and Resolute. At 1 year, the Orsiro stent was associated with lower rates of TLF compared with XIENCE (odds ratio [OR]: 0.84; 95% confidence interval [CI]: 0.71 to 0.98; p = 0.03), Resolute (OR: 0.81; 95% CI: 0.68 to 0.95; p = 0.01), and Nobori/BioMatrix (OR: 0.81; 95% CI: 0.67 to 0.98; p = 0.03). Orsiro had the highest probability to be the best (70.8%), with a surface under the cumulative ranking curve value of 95.9%. However, after a median follow-up period of 50 months (range: 24 to 60 months), no significant difference was apparent in the rates of TLF between any DES, although Orsiro still ranked as the best stent (58.6% probability to be the best). In addition, Orsiro had a lower rate of long-term definite stent thrombosis compared with Nobori/BioMatrix (OR: 0.60; 95% CI: 0.36 to 0.98; p = 0.04) and lower rates of definite and probable stent thrombosis compared with Resolute (OR: 0.66; 95% CI: 0.45 to 0.99; p = 0.04). No differences in cardiac mortality between any DES were observed.

CONCLUSIONS

Orsiro is associated with a lower 1-year rate of TLF compared with XIENCE, Resolute, and Nobori/BioMatrix but with an attenuation of the efficacy signal at long-term follow-up.

Stent strut streamlining and thickness reduction promote endothelialization

Stent thrombosis (ST) carries a high risk of myocardial infarction and death. Lack of endothelial coverage is an important prognostic indicator of ST after stenting. While stent strut thickness is a critical factor in ST, a mechanistic understanding of its effect is limited and the role of haemodynamics is unclear. Endothelialization was tested using a wound-healing assay and five different stent strut models ranging in height between 50 and 150 µm for circular arc (CA) and rectangular (RT) geometries and a control without struts. Under static conditions, all stent strut surfaces were completely endothelialized. Reversing pulsatile disturbed flow caused full endothelialization, except for the stent strut surfaces of the 100 and 150 µm RT geometries, while fully antegrade pulsatile undisturbed flow with a higher mean wall shear stress caused only the control and the 50 µm CA geometries to be fully endothelialized. Modest streamlining and decrease in height of the stent struts improved endothelial coverage of the peri-strut and stent strut surfaces in a haemodynamics dependent manner. This study highlights the impact of the stent strut height (thickness) and geometry (shape) on the local haemodynamics, modulating reendothelialization after stenting, an important factor in reducing the risk of stent thrombosis.

Development of biodegradable zein-based bilayer coatings for drug-eluting stents

Drug-eluting stents (DES) have been widely used for the treatment of cardiovascular diseases. Nevertheless, chronic inflammation and delayed re-endothelialization still represent challenges for their clinical use. In the present work, we developed novel bilayer coatings for stent applications that could overcome these limitations, exclusively using biodegradable plant-based drugs and polymers. In particular, stainless steel surfaces were coated with rutin-loaded zein (the active layer) and cross-linked alginate (the sacrificial layer) via facile dip and spray coating methods. Various mechanical tests and analysis tools, such as infrared spectroscopy, water contact angle measurements, and scanning electron microscopy were used to characterize the coated surfaces. Degradation and release studies of the films were extensively carried out and compared. The release rate of rutin from the bilayer coating reached 66.1 ± 3.2% within 24 hours of incubation (initial burst period), while the rest of the drug was released over 21 days in a sustained manner. Antioxidant assays confirmed that rutin retained its free radical scavenging ability after being eluted in phosphate buffer at 37 °C. In vitro results with human fibroblasts and endothelial cells suggested that the coating materials and their degradation products are highly biocompatible. In conclusion, our novel drug-eluting coatings, fabricated with natural biodegradable polymers, are promising materials for DES applications, allowing a sustained drug delivery and improving the biocompatibility of cardiovascular implanted devices.

Aneurysmal degeneration of fluoropolymer-coated paclitaxel-eluting stent in the superficial femoral artery: a rising concern

BACKGROUND

Although several clinical reports demonstrated a durable patency rate after a novel fluoropolymer-coated paclitaxel-eluting stent (Eluvia; Boston Scientific, Marlborough, MA, USA) placement, aneurysmal degeneration after drug-eluting stent (Eluvia) placement has raised clinical concerns. Here, we report a case with progressive aneurysm formation on serial angiography and intravascular ultrasound over 50 months after drug-eluting stent (Eluvia) placement for a superficial femoral artery atheromatous plaque.

CASE PRESENTATION

A 79-year-old woman with right leg intermittent claudication at 100 m distance was referred to our hospital. Pre-procedural angiography showed long-segment severe stenosis from the middle-to-distal part of the right superficial femoral artery, and a 7 mm wide drug-eluting stent (Eluvia) was placed. However, the patient had a recurrence of intermittent claudication in the right lower extremity 25 months thereafter. Angiography revealed de novo stenosis in the distal part of the popliteal artery and proximal superficial femoral artery in-stent restenosis. Subsequently, the patient underwent endovascular therapy for these lesions. In addition, intravascular ultrasound at the time of endovascular therapy revealed femoral artery enlargement with a maximum vessel diameter of 10.0 mm at the distal edge of the stent. Intermittent claudication on the right side recurred again 50 months after drug-eluting stent (Eluvia). Angiography demonstrated de novo severe stenosis from the distal part of the superficial femoral artery to the middle part of the popliteal artery. Peri-stent contrast staining was found at the distal part of the drug-eluting stent (Eluvia) site. Intravascular ultrasound showed a further enlargement of maximum vessel diameter to 12.0 mm at the distal edge of the stent.

CONCLUSIONS

We report a case with progressive aneurysm degeneration on serial angiography and intravascular ultrasound over 50 months after drug-eluting stent (Eluvia) placement for a superficial femoral artery stenosis.