Sirolimus and Paclitaxel on polymer-based drug-eluting stents: similar but different

Expanding indications for drug-coated balloons in coronary artery disease

INTRODUCTION

Despite technical advances in percutaneous coronary intervention (PCI) and new iterations of drug-eluting stents (DES), complications still occur, including stent thrombosis and in-stent restenosis (ISR). Drug-coated balloons (DCBs) provide a promising option for the treatment of coronary lesions - particularly when DES are undesirable or contraindicated - allowing for PCI without the implantation of metallic devices, thus adhering to the 'leave nothing behind' principle.

AREAS COVERED

A comprehensive literature search has been performed on PubMed, Web of Science and Cochrane, up to November 2024, with no significant restrictions. This article provides an overview of available DCB and summarizes the evidence supporting their use in different settings, including ISR, small-vessel disease, de novo large-vessel disease, and bifurcations.

EXPERT OPINION

Trials of DCB are heterogeneous with respect to population, sample size, follow-up, anatomical pattern, and device used. Furthermore, they usually have limited statistical power for clinical endpoints. Based on current knowledge, DES may be preferrable for DES-ISR, de novo lesions in large vessels and for the treatment of the main branch in true bifurcations, with DCB approved for small-vessel disease and selected ISR lesions. Ongoing trials are expected to provide definitive insights into the efficacy and safety of DCB in different scenarios.

Efficacy and Safety of Sirolimus-Coated Balloon Angioplasty in De Novo Lesions in Large Coronary Vessels: A Propensity Score-Matched Study

BACKGROUND

Evidence regarding drug-coated balloon (DCB)-only angioplasty in de novo lesions of large vessels is still limited and mainly focused on paclitaxel-coated balloon. We aimed to analyze the safety and efficacy of sirolimus-coated balloon (SCB)-only angioplasty in de novo lesions in large vessels compared to drug-eluting stent (DES).

METHODS

In this retrospective, dual-center, case-control study, we enrolled all consecutive patients treated between January 2022 and January 2024 with SCB-only angioplasty in de novo lesion in large vessel (> 2.75 mm) compared to a propensity-score matched contemporary population treated with DES. The primary endpoint was the rate of target lesion revascularization (TLR), while secondary endpoints were cardiac death (CD), target vessel revascularization (TVR), myocardial infarction (MI), and target lesion failure (TLF), defined as a composite of them.

RESULTS

The mean age was 70.1 ± 9.8 years in the SCB group (n = 92) and 67.9 ± 9.6 years in the DES group (n = 92) (p = 0.76). The median follow-up was 19.5 ± 12 months in the SCB group and 20.1 ± 13.1 months in the DES group (p = 0.47). TLR occurred in 6.7% of patients in the SCB group and 5.6% in the DES group (p = 0.75). The incidence of MI, TVR, and TLF were similar between the two groups (4.3% vs 3.3%, p = 0.7, 2.2% vs 3.4%, p = 0.65% and 9.8% vs 8.7%, p = 0.79). CD occurred in 4.3% in the SCB group, compared to 3.3% in the DES group (p = 0.70).

CONCLUSION

Our study suggests that SCB angioplasty is both safe and effective in the treatment of de novo lesions of large vessels compared with DES.

Real-World 12-Month Outcomes with Sirolimus-Coated Balloon Angioplasty for Complex Femoropopliteal Disease

Background: Sirolimus-coated balloons (SCBs) have emerged as a promising alternative to paclitaxel-coated devices for the treatment of femoropopliteal lesions. However, real-world data on SCB performance in also complex peripheral arterial disease remains unknown. We sought to evaluate the safety and 12-month clinical outcomes of the Selution SLR™ balloon angioplasty in a challenging real-world patient cohort. Methods: This single-center, retrospective observational study with prospective follow-up included 21 patients with symptomatic peripheral arterial disease treated with the Selution SLR™ SCB (Med. Alliance, SA, Mont-sur-Rolle, Switzerland) after vessel preparation with rotational atherectomy, between October 2023 and November 2024. The primary endpoints were technical success, 12-month primary patency, and target lesion revascularization (TLR). Secondary endpoints included major adverse cardiac events (MACE), major adverse limb events (MALE), and changes in Rutherford classification and ankle-brachial index (ABI). Results: The median age was 79 years, with 47.6% of patients over 80 years old. Most patients presented with advanced peripheral atherosclerotic disease (PAD) (Rutherford category V, 47.6%). Lesions were predominantly occlusive (76.2%), with a median length of 130 mm and severe/moderate calcified in 71.4% of cases. Technical success was achieved in 95.2% of procedures. The 12-month primary patency was 95%, with a TLR-Rate of 5%. No major amputations or cardiovascular deaths occurred. Significant improvements in Rutherford category and ABI were maintained at 12 months. Conclusions: In this real-world cohort of patients with complex PAD, vessel preparation-assisted Selution SLR™ angioplasty demonstrated safety and promising 12-month outcomes. These findings support the use of SCBs in also challenging peripheral interventions, though larger-scale data and further follow up are needed in order to establish SCBs' role as crucial in the treatment algorithm of PAD.

Moving away from metal: Step toward the future with bioresorbable vascular scaffolds and novel antiproliferative agents

Background

Peripheral arterial disease (PAD) is a common source of morbidity and mortality globally and is expected to raise increase in prevalence. Many endovascular techniques exist to manage PAD; however, there remains room for improvement, especially as it relates to below-the-knee vessels. Recent evidence and devices are leading to a resurgence of interest in bioresorbable vascular scaffolds and the -limus family of antiproliferative drugs in the PAD treatment space.

Methods

This nonsystematic review examines emerging technology for treatment of PAD with a specific focus on below-the-knee vessels and bioresorbable vascular scaffolds. Additional emerging and early technology such as novel delivery platforms are also briefly discussed with directions of future research highlighted.

Results

Bioresorbable vascular scaffold biomechanics and history are highlighted. Foundational knowledge of antiproliferative agents and evolving agents in peripheral vascular disease are also described.

Conclusions

Bioresorbable vascular scaffolds are an additional endovascular tool for the treatment of peripheral vascular disease. The integration with an antiproliferative agent may result in improved patency and performance; however, there is a paucity of data in the literature at present.

Is the axiom of balloon angioplasty, "the more you gain the more you lose," still true in the era of DCB with paclitaxel?

Balloon angioplasty achieves luminal enlargement by fracturing the atherosclerotic intima at its point of least resistance, thereby creating a dissection plane and space with dehiscence of the intima from the media. This barotraumatic dissection triggers an inflammatory and proliferative reaction, resulting in a restenosis process at medium-term. In the era of plain old balloon angioplasty, quantitative angiographic studies at follow-up demonstrated that - the greater the acute luminal gain was after balloon angioplasty, the greater the late luminal loss was at follow-up. The interventional cardiologists coined the following motto "the more you gain, the more you lose". However, in the current era of drug coated balloon (DCB), it appears that this vexing conundrum could have been abrogated. A recently published DCB study in small de novo vessel has demonstrated that there was a slightly negative correlation between the volume of dissection assessed by optical coherence tomography and the angiographic late luminal loss (now gain) after Paclitaxel coated balloon treatment. In other words, the barotraumatic dissection does not necessarily herald a restenosis process in the era of DCB. This article revisits the mechanism of balloon angioplasty and explores how DCB with Paclitaxel may change the paradigm of balloon angioplasty as default treatment in CAD percutaneous treatment.

Drug-coated balloons for coronary artery disease: An updated review with future perspectives

Since the advent of coronary stents, two of the most common long-term complications after percutaneous coronary intervention (PCI) are in-stent restenosis (ISR) and stent thrombosis (ST). Although the rates of ST have been nearly abolished and ISR rates have declined with the current gold-standard second-generation drug-eluting stents (DES), late ISR of DES remains a valid concern in the field of interventional cardiology. The drug-coated balloon (DCB) is a non-stent technology that relies on the concept of targeted homogeneous drug delivery from an inflated balloon to restore luminal vascularity, treat atherosclerosis, and overcome some limitations of PCI, including ISR and prolonged dual antiplatelet therapy to prevent ST by leaving nothing behind. Most clinical evidence on coronary DCBs predominantly comes from small, randomized data and registries using paclitaxel DCBs for ISR and de novo lesions in the coronary space. Since 2014, outside the United States, DCBs have been approved for the treatment of ISR, with a class I recommendation by the European Society of Cardiology. The Food and Drug Administration very recently approved the Agent DCB to treat ISR in patients with coronary artery disease in the US. Additionally, recent randomized clinical data also showed DCB's safety and efficacy for the treatment of de novo small-vessel disease and high-bleeding-risk patients, while their role for other clinical situations including acute coronary syndrome, large-vessel disease, bifurcation lesions, and long-diffuse distal lesions is currently under investigation. Herein, we review the evidence-based role of DCBs in the treatment of coronary lesions and offer future perspectives.

Paclitaxel-coated versus sirolimus-coated balloon angioplasty for coronary artery disease: A systematic review and meta-analysis

BACKGROUND

Although use of sirolimus-based analogs has shown superiority over paclitaxel in drug-eluting stents, the relative efficacy of these two agents released from drug-coated balloons (DCB) is unclear. The present meta-analysis is aimed to compare outcomes after percutaneous coronary intervention (PCI) with paclitaxel-coated balloons (PCB) versus sirolimus-coated balloons (SCB) for either in-stent restenosis or native de novo lesions.

METHODS

The study outcomes were 1) target lesion failure (TLF), a composite of cardiac death, target vessel myocardial infarction, or target lesion revascularization, and 2) follow-up angiographic parameters including late lumen loss (LLL), diameter stenosis, and minimal lumen diameter (MLD). Pooled odds ratios (OR) and weighted mean differences (WMD) with 95% confidence intervals (CI) were calculated by using random-effects models.

RESULTS

A search of PubMed, EMBASE, and Cochrane Library from their inception to January 2024 identified five randomized clinical trials and three observational studies with a total of 1861 patients (889 in PCB and 972 in SCB groups). During 9-12 months of follow-up, there was no significant difference in TLF (OR 1.01, 95% CI 0.75-1.35) between the two groups. On follow-up angiography at 6-9 months, MLD (WMD 0.10, 95% CI 0.02-0.17) was larger in PCB but there was no statistically significant difference in LLL (WMD -0.11, 95% CI -0.23-0.02) and diameter stenosis (WMD -3.33, 95% CI -8.11-1.45).

CONCLUSIONS

Among patients undergoing DCB-only PCI, the risk of TLF was similar during 9-12 months of follow-up after PCB and SCB treatment. However, the MLD was larger favoring PCB over SCB on follow-up angiography.

MagicTouch PTA Sirolimus-Coated Balloon for Femoropopliteal and Below-the-Knee Disease: 3-Year Outcomes of the XTOSI Trial

BACKGROUND

Sirolimus-coated balloon (SCB) is a potential treatment option for peripheral arterial disease (PAD). There are currently no long-term clinical data for this novel treatment for PAD. We present the 3-year results of the first-in-human study of MagicTouch PTA SCB for treatment of PAD for both femoropopliteal and below-the-knee arteries.

METHODS

The XTOSI pilot study is a prospective, single-arm, open-label, single-center trial evaluating MagicTouch PTA SCB for symptomatic PAD. Assessments through 3 years included freedom from clinically driven target lesion revascularization (CD-TLR), freedom from major amputation, amputation-free survival (AFS), overall survival, and ulcer-free status.

RESULTS

At 3 years, the overall freedom from CD-TLR was 84.4%, freedom from major amputation was 86.1%, AFS was 63.3%, overall survival was 63.3%, and ulcer-free status in remaining survivors with intact limbs was 100%. For femoropopliteal lesions, at 3 years, the freedom from CD-TLR was 92.9%, freedom from major amputation was 93.3%, AFS was 70%, and overall survival was 70%. For below-the-knee lesions, at 3 years, the freedom from CD-TLR was 77.8%, freedom from major amputation was 81.0%, AFS was 58.6%, and overall survival was 58.6%.

CONCLUSIONS

SCB in the XTOSI pilot study showed promising clinical results sustained to 3 years, and no long-term safety concerns were raised. Randomized trials are currently ongoing to investigate the safety and efficacy of SCB for treatment of PAD.

Outcomes With Limus- vs Paclitaxel-Coated Balloons for Percutaneous Coronary Intervention: Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Randomized controlled trials (RCTs) examining the outcomes with limus drug-coated balloons (DCBs) vs paclitaxel DCBs were small and underpowered for clinical endpoints.

OBJECTIVES

This study sought to compare the angiographic and clinical outcomes with limus DCBs vs paclitaxel DCBs for percutaneous coronary intervention (PCI).

METHODS

An electronic search of Medline, EMBASE, and Cochrane databases was performed through January 2024 for RCTs comparing limus DCBs vs paclitaxel DCBs for PCI. The primary endpoint was clinically driven target lesion revascularization (TLR). The secondary endpoints were late angiographic findings. Summary estimates were constructed using a random effects model.

RESULTS

Six RCTs with 821 patients were included; 446 patients received a limus DCB, and 375 patients received a paclitaxel DCB. There was no difference between limus DCBs and paclitaxel DCBs in the incidence of TLR at a mean of 13.4 months (10.3% vs 7.8%; risk ratio [RR]: 1.32; 95% CI: 0.84-2.08). Subgroup analysis suggested no significant interaction among studies for de novo coronary lesions vs in-stent restenosis (Pinteraction = 0.58). There were no differences in the risk of major adverse cardiovascular events, cardiac mortality, or target vessel myocardial infarction between groups. However, limus DCBs were associated with a higher risk of binary restenosis (RR: 1.89; 95% CI: 1.14-3.12), late lumen loss (mean difference = 0.16; 95% CI: 0.03-0.28), and a smaller minimum lumen diameter (mean difference = -0.12; 95% CI: -0.22 to -0.02) at late follow-up. In addition, late lumen enlargement occurred more frequently (50% vs 27.5%; RR: 0.59; 95% CI: 0.45-0.77) with paclitaxel DCBs.

CONCLUSIONS

Among patients undergoing DCB-only PCI, there were no differences in the risk of clinically driven TLR and other clinical outcomes between limus DCBs and paclitaxel DCBs. However, paclitaxel DCBs were associated with better late angiographic outcomes. These findings support the need for future trials to establish the role of new-generation limus DCBs for PCI.

Efficacy and Safety of Dual Paclitaxel and Sirolimus Nanoparticle-Coated Balloon

We evaluated a novel dual active pharmaceutical ingredient (API) drug-coated balloon (DCB), which consists of a coating of nanoparticles encapsulating low-dose paclitaxel (PTX) in combination with sirolimus in a synergistic ratio. Compared to the PTX DCB, the dual API DCB demonstrated similar inhibition of cell proliferation in vitro but at a significantly lower total drug dose (over 13 times lower than sirolimus nanoparticles). Animal experiments demonstrated that the dual API DCB is more effective in inhibiting intimal cell proliferation with insignificant downstream embolic effects and myocardial damage compared to the PTX DCB. These findings indicate that dual API DCBs have a high potential to demonstrate improved clinical outcomes and a greater safety profile than the PTX DCBs.

Investigating the anti-atherosclerotic effects and potential mechanism of Dalbergia odorifera in ApoE-deficient mice using network pharmacology combined with metabolomics

Dalbergia odorifera (DO) is a precious rosewood species in Southern Asia, and its heartwood is used in China as an official plant for invigorating blood circulation and eliminating stasis. This study aims to evaluate the efficacy of DO on atherosclerosis (AS), and further explore its active components and potential mechanisms. The apolipoprotein-E (ApoE)-deficient mice fed a high-fat diet were used as model animals, and the pathological changes in mice with or without DO treatment were compared to evaluate the pharmacodynamics of DO on AS. The mechanisms were preliminarily expounded by combining with metabolomics and network pharmacology. Moreover, the bioactive components and targets were assessed by cell experiments and molecular docking, respectively. Our findings suggested that DO significantly modulated blood lipid levels and alleviated intimal hyperplasia in atherosclerotic-lesioned mice, and the mechanisms may involve the regulation of 18 metabolites that changed during the progression of AS, thus affecting 3 major metabolic pathways and 3 major signaling pathways. Moreover, the interactions between 16 compounds with anti-proliferative effect and hub targets in the 3 signaling pathways were verified using molecular docking. Collectively, our findings preliminarily support the therapeutic effect of DO in atherosclerosis, meanwhile explore the active constituents and potential pharmacological mechanisms, which is conducive to its reasonable exploitation and utilization.

Passivation protein-adhesion platform promoting stent reendothelialization using two-electron-assisted oxidation of polyphenols

Superhydrophilic surfaces play an important role in nature. Inspired by this, scientists have designed various superhydrophilic materials that are widely used in the field of biomaterials, such as PEG molecular brushes and zwitterionic materials. However, superhydrophilic coatings with only anti-fouling properties do not satisfy the requirements for rapid reendothelialization of cardiovascular stent surfaces. Herein, a novel polyphenol superhydrophilic surface with passivated protein-adsorption properties was developed using two-electron oxidation of dopamine and polyphenols. This coating has a multiscale effects: 1) macroscopically: anti-fouling properties of superhydrophilic; 2) microscopically: protein adhesion properties of active groups (quinone-, amino-, hydroxyphenyl groups and aromatic ring). Polyphenols not only enhance the ability of coating to passivate protein-adsorption, but also make the coating have polyphenol-related biological functions. Therefore, the polyphenol and passivated protein-adsorption platform together maintain the stability of the scaffold microenvironment. This, in turn, provides favorable conditions for the growth of endothelial cells on the scaffold surface. In vivo implantation of the coated stents into the abdominal aorta resulted in uniform and dense endothelial cells covering the surface of the neointima. Moreover, new endothelial cells secreted large amounts of functional endothelial nitric oxide synthase like healthy endothelial cells. These results indicate that the polyphenol superhydrophilic coating potentially resists intra-stent restenosis and promotes surface reendothelialization. Hence, polyphenol superhydrophilic coatings with passivated protein-adsorption properties constructed by two-electron-assisted oxidation are a highly effective and versatile surface-modification strategy for implantable cardiovascular devices.

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.

Synchrotron microtomography reveals insights into the degradation kinetics of bio-degradable coronary magnesium scaffolds

Bioresorbable magnesium scaffolds are a promising future treatment option for coronary artery stenosis, especially for young adults. Due to the degradation of these scaffolds (<1 year), long-term device-related clinical events could be reduced compared to treatments with conventional drug eluting stents. First clinical trials indicate a return of vasomotion after one year, which may be associated with improved long-term clinical outcomes. However, even after decades of development, the degradation process, ideal degradation time and biological response in vivo are still not fully understood. The present study investigates the in vivo degradation of magnesium scaffolds in the coronary arteries of pigs influenced by different strut thicknesses and the presence of antiproliferative drugs. Due to high 3D image contrast of synchrotron-based micro-CT with phase contrast (SR-μCT), a qualitative and quantitative evaluation of the degradation morphology of magnesium scaffolds was obtained. For the segmentation of the μCT images a convolutional network architecture (U-net) was exploited, demonstrating the huge potential of merging high resolution SR-μCT with deep learning (DL) supported data analysis. In total, 30 scaffolds, made of the rare earth alloy Resoloy®, with different strut designs were implanted into the coronary arteries of 10 domestic pigs for 28 days using drug-coated or uncoated angioplasty balloons for post-dilatation. The degradation morphology was analyzed using scanning electron microscopy, energy dispersive x-ray spectroscopy and SR-μCT. The data from these methods were then related to data from angiography, optical coherence tomography and histology. A thinner strut size (95 vs. 130 μm) and the presence of paclitaxel indicated a slower degradation rate at 28 d in vivo, which positively influences the late lumen loss (0.5 and 0.6 mm vs. 1.0 and 1.1 mm) and recoil values (0 and 1.7% vs. 6.1 and 22%).

A Prospective Randomized Trial Comparing Sirolimus-Coated Balloon With Paclitaxel-Coated Balloon in De Novo Small Vessels

BACKGROUND

There are no data comparing sirolimus-coated balloons (SCBs [MagicTouch, Concept Medical]) to paclitaxel-coated balloons (PCBs [SeQuent Please Neo, B. Braun]) for the treatment of de novo small vessel disease (SVD).

OBJECTIVES

This study sought to compare quantitative coronary angiographic outcomes at 6 months after treatment of de novo SVD with a PCB or SCB.

METHODS

This prospective, multicenter, noninferiority trial randomized 121 patients (129 SVD lesions) to treatment with an SCB or PCB, with balloon sizing determined using optical coherence tomography. The primary endpoint was noninferiority for the 6-month angiographic net lumen gain.

RESULTS

Angiographic follow-up was completed in 109 (90.1%) patients in the per-protocol analysis. The mean ± SD angiographic net gains were 0.25 ± 0.40 mm with SCBs vs 0.48 ± 0.37 mm with PCBs, resulting in SCBs failing to meet the 0.30 mm criterion for noninferiority (Pnoninferiority = 0.173), with an absolute difference of -0.23 mm (95% CI: -0.37 to -0.09) secondary to a smaller late loss (0.00 ± 0.32 mm vs 0.32 ± 0.47 mm; P < 0.001) and more frequent late lumen enlargement (53.7% vs 30.0%; OR: 2.60; 95% CI: 1.22-5.67; P = 0.014) with PCBs. Binary restenosis rates were 32.8% and 12.5% following treatment with SCBs and PCBs, respectively (OR: 3.41; 95% CI: 1.36-9.44; P = 0.012). The mean angiography-derived fractional flow ratio at follow-up was 0.86 ± 0.15 following treatment with SCBs and 0.91 ± 0.09 following PCBs (P = 0.026); a fractional flow ratio ≤0.80 occurred in 13 and 5 vessels after treatment with SCBs and PCBs, respectively.

CONCLUSIONS

The SCB MagicTouch failed to demonstrate noninferiority for angiographic net lumen gain at 6 months compared to the PCB SeQuent Please Neo.

Surface Engineering of Bioactive Coatings for Improved Stent Hemocompatibility: A Comprehensive Review

Cardiovascular diseases continue to be a major contributor to illness and death on a global scale, and the implementation of stents has given rise to a revolutionary transformation in the field of interventional cardiology. The thrombotic and restenosis complications associated with stent implantation pose ongoing challenges. In recent years, bioactive coatings have emerged as a promising strategy to enhance stent hemocompatibility and reduce thrombogenicity. This review article provides an overview of the surface engineering techniques employed to improve the hemocompatibility of stents and reduce thrombus formation. It explores the mechanisms underlying thrombosis and discusses the factors influencing platelet activation and fibrin formation on stent surfaces. Various bioactive coatings, including anticoagulant agents, antiplatelet agents, and surface modifications, are discussed in detail, highlighting their potential in reducing thrombogenicity. This article also highlights a multitude of surface modification techniques which can be harnessed to enhance stent hemocompatibility including plasma treatment, physical vapor deposition (PVD), chemical vapor deposition (CVD), and electrodeposition. These techniques offer precise control over surface properties such as roughness, charge, and composition. The ultimate goal is to reduce platelet adhesion, tailor wettability, or facilitate the controlled release of bioactive agents. Evaluation methods for assessing hemocompatibility and thrombogenicity are also reviewed, ranging from in vitro assays to animal models. Recent advances in the field, such as nanotechnology-based coatings and bioactive coatings with controlled drug release systems, are highlighted. Surface engineering of bioactive coatings holds great promise for enhancing the long-term outcomes of stent implantation by enhancing hemocompatibility and reducing thrombogenicity. Future research directions and potential clinical applications are discussed, underscoring the need for continued advancements in this field.

Pre-clinical investigation of liquid sirolimus for local drug delivery

Introduction

Sirolimus is currently being explored as an alternative drug to paclitaxel for the treatment of peripheral artery disease (PAD). To date, sirolimus has only been used as drug coatings for stents and balloons and no studies have yet demonstrated the delivery of sirolimus in liquid form. The purpose of this pilot study was to investigate the feasibility of the delivery of liquid sirolimus into arterial segments in a benchtop peripheral artery bioreactor.

Methods

The feasibility to deliver liquid therapy was first tested on four drug delivery devices using a fluorescently tagged liquid drug and an ex vivo porcine artery benchtop model. The four devices included the Bullfrog micro-infusion device, ClearWay RX catheter, Occlusion perfusion catheter (OPC), and the targeted adjustable pharmaceutical administration system (TAPAS). Penetration of the fluorescently tagged drug was measured via microscopic imaging and quantification of the depth of drug penetration into all device-treated tissue. Based on the penetration outcome, we then selected a single device to deliver liquid sirolimus into the ex vivo porcine artery model undergoing physiological flow and pressure conditions. The liquid sirolimus-treated arteries were collected from the ex vivo bioreactor at 1- and 24-hour post-delivery and arterial drug retention analyzed by liquid chromatography-tandem mass spectrometry.

Results

Fluorescent microscopy demonstrated that drug delivery with the OPC had greater drug penetration into the medial wall as compared to other devices (OPC: 234 ± 161 µm; TAPAS: 127 ± 68 µm; ClearWay: 118 ± 77 µm; Bullfrog: 2.12 ± 3.78 µm; p = 0.098). The results of the ex vivo flow-circuit bench top model showed that the OPC device successfully delivered the liquid sirolimus at 1-hour (5.17 ± 4.48 ng/mg) and 24-hour (0.78 ± 0.55 ng/mg).

Conclusions

These results demonstrate for the first time the ability to deliver liquid sirolimus directly to the medial layer of an artery via a liquid delivery catheter.

Liquid Metal-Based Flexible Bioelectrodes for Management of In-Stent-Restenosis: Potential Application

Although vascular stents have been widely used in clinical practice, there is still a risk of in-stent restenosis after their implantation. Combining conventional vascular stents with liquid metal-based electrodes with impedance detection, irreversible electroporation, and blood pressure detection provides a new direction to completely solve the restenosis problem. Compared with conventional rigid electrodes, liquid metal-based electrodes combine high conductivity and stretchability, and are more compliant with the implantation process of vascular stents and remain in the vasculature for a long period of time. This perspective reviews the types and development of conventional vascular stents and proposes a novel stent that integrates liquid metal-based electrodes on conventional vascular stents. This vascular stent has three major functions of prediction, detection and treatment, and is expected to be a new generation of cardiovascular implant with intelligent sensing and real-time monitoring.

Osteopontin is a key regulator of vascular smooth muscle cell proliferation in the outflow vein of arteriovenous fistulas

OBJECTIVES

Despite advances in the maintenance of arteriovenous fistulas (AVFs), the patency rates remain suboptimal. Most AVFs fail due to outflow vein stenosis; however, the underlying mechanism of AVF stenosis remains unclear. The present study aimed to identify key factors associated with AVF outflow stenosis.

METHODS

We obtained gene expression profiling data for the outflow vein of AVF from three Gene Expression Omnibus database datasets (GSE39488, GSE97377, and GSE116268) and analyzed the common differentially expressed genes (DEGs). We evaluated a common DEG in an aortocaval mouse model and the stenotic outflow veins of AVFs collected from patients. Furthermore, we isolated vascular smooth muscle cells (VSMCs) from the inferior vena cava (IVC) of wild-type (WT) and osteopontin (Opn)-knockout (KO) mice and assessed the proliferation of VSMCs following stimulation with platelet-derived growth factors (PDGFs).

RESULTS

OPN was the only common upregulated DEG among all datasets. OPN was expressed in the medial layer of the outflow vein of AVF in aortocaval mouse models and co-stained with the VSMC marker (α-smooth muscle actin). OPN expression was markedly increased in the VSMCs of stenotic outflow veins of AVF collected from patients undergoing hemodialysis compared to presurgical veins acquired during AVF formation surgery. PDGF-induced VSMC proliferation was significantly increased in the VSMCs isolated from the IVC of WT mice but not in those isolated from the IVC of Opn-KO mice.

CONCLUSIONS

OPN may be a key gene involved in VSMC proliferation in the AVF outflow veins and a therapeutic target to improve the AVF patency rate.

Coronary Drug-Coated Balloons for De Novo and In-Stent Restenosis Indications

Drug-coated balloons are approved outside the United States, not only for the treatment of peripheral arteries but also for coronary arteries. This review describes the technological basics, the scenarios of clinical application, and the current available data from clinical trials for the different coronary indications.

Intervention with selution SLR™ Agent Balloon for Endovascular Latent Limus therapy for failing AV Fistulas (ISABELLA) Trial: Protocol for a pilot clinical study and pre-clinical results

BACKGROUND

The aim of this pilot clinical study is to evaluate the safety and efficacy of the Selution Sustained Limus Release (SLR)™ sirolimus-coated balloon (M.A. MedAlliance SA, Nyon, Switzerland) for improving the patency of failing arterio-venous fistulas (AVF) in hemodialysis patients. We also present herein a pre-clinical pharmacokinetic and safety evaluation of Selution™ to justify its first use in hemodialysis patients for endovascular access salvage.

METHODS AND RESULTS

This is an investigator-initiated prospective single-center, non-blinded single-arm trial. Forty patients with clinically significant de novo or recurrent stenoses in a mature AVF circuit will be recruited. All stenotic lesions will be prepared with high pressure non-compliant conventional balloon angioplasty (CBA) prior to deployment of the Sustained-Release Selution™ sirolimus drug-eluting balloon. The primary efficacy endpoint is 6-month target lesion primary patency and the primary safety endpoint is freedom from localized or systemic serious adverse events through 30 days. Secondary endpoints of interest include technical and clinical success rates and circuit access patency at 3 and 6 months. Follow-up will occur for 2 years for those patients whose AVFs remain patent. Pharmacokinetic and histological animal safety studies performed with the Selution™ coating formulation showed prolonged arterial tissue retention of sirolimus with therapeutic levels up to 60 days and non-toxic and rapidly declining blood levels. Histological results in animal models demonstrated safety, freedom from intraluminal thrombus, reduction in restenosis by sirolimus elution compared to CBA, and no evidence of embolic phenomena indicative of adverse particulate effects.

DISCUSSION

Long release sirolimus coated balloons may serve as a promising novel alternative therapy to paclitaxel-based technology for treating conduit stenosis secondary to neointimal hyperplasia. Pre-clinical pharmacokinetic and histological animal data are encouraging and provide suggestion of safety and efficacy in this setting. This single-center trial will provide a first step toward demonstration of efficacy and safety of this device for treatment of stenotic fistulas.

Modeling Dual Drug Delivery from Eluting Stents: The Influence of Non-Linear Binding Competition and Non-Uniform Drug Loading

OBJECTIVE

There is increasing interest in simultaneous endovascular delivery of more than one drug from a drug-loaded stent into a diseased artery. There may be an opportunity to obtain a therapeutically desirable uptake profile of the two drugs over time by appropriate design of the initial drug distribution in the stent. Due to the non-linear, coupled nature of diffusion and reversible specific/non-specific binding of both drugs as well as competition between the drugs for a fixed binding site density, a comprehensive numerical investigation of this problem is critically needed.

METHODS

This paper presents numerical computation of dual drug delivery in a stent-artery system, accounting for diffusion as well as specific and non-specific reversible binding. The governing differential equations are discretized in space, followed by integration over time using a stiff numerical solver. Three different cases of initial dual drug distribution are considered.

RESULTS

For the particular case of sirolimus and paclitaxel, results show that competition for a limited non-specific binding site density and the significant difference in the forward/backward reaction coefficients play a key role in determining the nature of drug uptake. The nature of initial distribution of the two drugs in the stent is also found to influence the binding process, which can potentially be used to engineer a desirable dual drug uptake profile.

CONCLUSIONS

These results help improve the fundamental understanding of endovascular dual drug delivery. In addition, the numerical technique and results presented here may be helpful for designing and optimizing other drug delivery problems as well.

Efficacy and Safety of TiNO-Coated Stents versus Drug-Eluting Stents in Acute Coronary Syndrome: Systematic Literature Review and Meta-Analysis

(1) Background: Practice guidelines define drug-eluting stents (DES) as the standard of care in coronary percutaneous coronary intervention (PCI), including in acute coronary syndrome (ACS). This is based on comparisons with bare-metal stents (BMS). However, non-drug-eluting titanium-nitride-oxide-coated stents (TiNOS) have not been taken into account. The objective of this study is to determine whether TiNOS can be used as an alternative to DES in ACS. (2) Methods: A prospective systematic literature review (SLR), conducted according to the PRISMA guidelines, was performed, wherein multiple literature databases from 2018 and 2022 were searched. Prospective, randomised, controlled trials comparing outcomes after PCI with TiNOS vs. DES in any coronary artery disease (CAD) were searched. Clinical outcomes were meta-analytic pooled risk ratios (RR) of device-oriented Major Adverse Cardiac Events (MACE) and their components. The analysis stratified outcomes reported with ACS-only vs. ACS jointly with chronic coronary syndrome (CCS). (3) Results: Five RCTs were eligible, comprising 1855 patients with TiNOS vs. 1363 with DES at a 1-year follow-up. Three enrolled patients presented with ACS only and two with ACS or CCS. The latter accounted for most of the patients. The one-year pooled RRs in those three RCTs were as follows: MACE 0.93 [0.72, 1.20], recurrent myocardial infarction (MI) 0.48 [0.31, 0.73], cardiac death (CD) 0.66 [0.33, 1.31], clinically driven target lesion revascularization (TLR) 1.55 [1.10, 2.19], and stent thrombosis (ST) 0.35 [0.20, 0.64]. Those results were robust to a sensitivity analysis. The evidence certainty was high in MACE and moderate or low in the other endpoints. (4) Conclusions: TiNOS are a non-inferior and safe alternative to DES in patients with ACS.

How does the Nature of an Excipient and an Atheroma Influence Drug-Coated Balloon Therapy?

The advent of drug-eluting stents and drug-coated balloons have significantly improved the clinical outcome of patients with vascular occlusions. However, ischemic vascular disease remains the most common cause of death worldwide. Improving the current treatment modalities demands a better understanding of the processes which govern drug uptake and retention in blood vessels. In this study, we evaluated the influence of urea and butyryl-trihexyl citrate, as excipients, on the efficacy of drug-coated balloon therapy. An integrated approach, utilizing both in-vitro and in-silico methods, was used to quantify the tracking loss, vessel adhesion, drug release, uptake, and distribution associated with the treatment. Moreover, a parametric study was used to evaluate the potential influence of different types of lesions on drug-coated balloon therapy. Despite the significantly higher tracking loss (urea: 35.5% vs. butyryl-trihexyl citrate: 8.13%) observed in the urea-based balloons, the drug uptake was almost two times greater than with its hydrophobic counterpart. Non-calcified lesions were found to delay the transmural propagation of sirolimus while calcification was shown to limit the retentive potential of lesions. Ultimately this study helps to elucidate how different excipients and types of lesions may influence the efficacy of drug-coated balloon therapy.

Drug-Eluting Stents are Associated with Superior Mid-Term Outcomes for the Treatment of Infrainguinal Bypass Graft Stenoses

BACKGROUND

We previously demonstrated that everolimus drug-eluting stents (eDES) have reasonable short-term patency for the treatment of infrainguinal bypass stenoses. The aim of this study is to compare mid-term outcomes of eDES, plain balloon angioplasty (PTA), percutaneous cutting balloon (PCB), and drug-coated balloon (DCB) interventions for failing infrainguinal bypasses.

METHODS

We conducted a retrospective review of patients with infrainguinal bypass stenoses treated by endovascular intervention (August 2010-August 2021). The primary outcome was primary patency (PP). Secondary outcomes were primary-assisted patency (PAP), secondary patency (SP), limb salvage (LS), and mortality. Outcomes were compared by treatment using Kaplan-Meier curves with log-rank tests and Cox proportional hazards models adjusting for baseline differences between groups.

RESULTS

Seventy-two consecutive patients with 152 discrete infrainguinal bypass graft stenoses were identified. Mean age was 65.1 ± 10.6 years, 55.6% were male, and 48.6% were Black. In total, 81.9% of patients were originally treated for chronic limb-threatening ischemia, and 57.2% of distal anastomoses were to tibial or pedal targets. Of 152 lesions, 44.1% (n = 67) were treated with PTA, 17.8% (n = 27) with PCB, 20.4% (n = 31) with DCB, and 17.8% (n = 27) with eDES. Median follow-up was 28.5 months (interquartile range 11.5-51.9). There was no difference in bypass configuration, conduit choice, or stenosis location (proximal anastomosis, mid-bypass, distal anastomosis) between groups. At 24 months postintervention, PP was significantly better for eDES (72.9%, 95% confidence interval [CI] 49.8-85.6), followed by PCB (55.9%, 95% CI 34.2-72.9), PTA (34.4%, 95% CI 21.7-47.4), and DCB (33.6%, 95% CI 14.5-53.9) (P = 0.03). PAP, LS, and mortality did not significantly differ between modalities (P > 0.05). After risk adjustment, eDES was associated with the lowest risk of PP loss (hazard ratio versus PTA 0.15, 95% CI 0.05-0.47).

CONCLUSIONS

eDES is associated with superior 24-month patency rates compared to other endovascular technologies, and should be considered a primary therapy modality for the treatment of infrainguinal bypass graft stenoses.

Sirolimus-coated balloon versus everolimus-eluting stent in de novo coronary artery disease: Rationale and design of the TRANSFORM II randomized clinical trial

BACKGROUND

Percutaneous coronary intervention (PCI) with drug-eluting stent (DES) implantation is a widely adopted strategy for the treatment of de novo coronary artery disease. DES implantation conveys an inherent risk for short- and long-term complications, including in-stent restenosis and stent thrombosis. Drug-coated balloons are emerging as an alternative approach to fulfill the "leaving nothing behind" principle and avoid long-term DES-related complications.

DESIGN

TRANSFORM II is an investigator-initiated, multicenter, noninferiority, randomized clinical trial, testing a sirolimus-coated balloon (SCB) versus the standard of care for native coronary vessels with a 2-3 mm diameter, in terms of 12-month target lesion failure (TLF; primary endpoint) and net adverse cardiovascular events (coprimary endpoint). Patients undergoing PCI will be randomized to be treated with either SCB or new-generation everolimus-eluting stent and will be followed up clinically for up to 60 months. Assuming a TLF rate of 8% at 12 months with DES, a sample size of 1325 patients was chosen to ensure an 80% power to detect a 1.5% lower incidence in the SCB group with a type I error rate of 0.05. The TRANSFORM II trial is registered on clinicaltrials.gov (identification number NCT04893291). Several substudies, including an optical coherence tomography assessment at 9 months (intracoronary imaging substudy), will investigate the study device in different clinical and lesion settings.

CONCLUSIONS

The randomized TRANSFORM II trial will determine whether a novel SCB is noninferior to a current everolimus-eluting stent when adopted for the treatment of de novo lesions in coronary vessels with a diameter between 2 and 3 mm.

Medikamentenbeschichtete Ballons bei PAVK

Paclitaxel-beschichtete Ballons bei femoropoplitealen Läsionen Für die Behandlung femoropoplitealer Gefäßläsionen, bei Verschlusslängen unter 25 cm sowie bei längeren Verschlüssen (wenn kein Venenmaterial vorliegt und/oder das Operationsrisiko hoch ist), wird die endovaskuläre Therapie empfohlen. Um Restenosierungen und Reinterventionen zu vermeiden, wird dabei die Verwendung von medikamentenbeschichteten Ballons empfohlen. Durch die Weiterentwicklung des Ballondesigns kann die Effektivität noch gesteigert werden.

Paclitaxel-beschichtete Ballons bei infrapoplitealen Läsionen Im Stadium der kritischen Extremitäten-Ischämie wird bei infrapoplitealen Gefäßläsionen primär ebenfalls ein endovaskulärer Therapieansatz empfohlen. Aufgrund von inkonsistenten, teilweise widersprüchlichen Ergebnissen verschiedener klinischer Studien, kann der Vorteil medikamentenbeschichteter Ballons bei der Angioplastie infrapoplitealer Arterien bislang nicht ausreichend beurteilt werden.

Sicherheitsaspekt Paclitaxel-beschichteter Ballons Zahlreiche Real-World-Studien und Nachauswertungen prospektiver Studien konnten den in einer früheren Metaanalyse postulierten Zusammenhang einer höheren Mortalität nach Anwendung Paclitaxel-beschichteter Devices weder bestätigen noch einen möglichen Pathomechanismus oder eine Dosis-Wirkungs-Beziehung aufzeigen. Dennoch wurden die Empfehlungen des Bundesinstituts für Arzneimittel und Medizinprodukte (BfArM) zur sorgfältigen Nutzen-Risiko-Abwägung und Aufklärungspflicht noch nicht angepasst.

Sirolimus-beschichtete Ballons Mit dem Zytostatikum Sirolimus steht eine weitere antiproliferativ und zusätzlich antientzündlich wirkende Substanz zur Vermeidung von Restenosierungen bei femoropoplitealen und infrapoplitealen Läsionen zur Verfügung. Die therapeutische Breite von Sirolimus ist zwar größer als die von Paclitaxel, dennoch ist die Gewebeabsorption und -retention von Sirolimus deutlich schwieriger. Erste Ergebnisse aus kleineren Studien, die die Sicherheit und Effektivität Sirolimus-beschichteter Ballons untersuchten, sind vielversprechend, müssen allerdings noch in großen, prospektiven, randomisierten Studien bewiesen werden.

Rapamycin and Paclitaxel Affect Human Aortic Smooth Muscle Cells-Derived Foam Cells Viability and Proliferation

INTRODUCTION

Drug-eluting stents (DES) coated with rapamycin or paclitaxel as antiproliferative substances significantly reduced the incidence of clinical restenosis and had fewer side effects after percutaneous coronary intervention. However, DES coated with rapamycin or paclitaxel still cause restenosis due to abnormal tissue growth which remained a therapeutic problem, particularly in certain subgroups, possibly due to drug concentrations. This study examined the impact of different concentrations of rapamycin and paclitaxel on cytokine, cell viability and proliferation in human aortic smooth muscle cells (HASMC)-derived foam cells.

METHODS

The foam cell model was established in vitro by incubating HASMC with 20 µg/mL oxidized low-density lipoprotein (ox-LDL) for 48 hours. Subsequently, foam cells were treated with different concentrations (0.01 µg/mL, 0.1 µg/mL, 0.5 µg/mL, 1 µg/mL, 5 µg/mL and 10 µg/mL) of rapamycin or paclitaxel for 48 hours, to measure cytokine, cell viability and proliferation by ELISA and MTT, respectively. Finally, viability and proliferation were measured by MTT after the foam cells were treated with 1 µg/mL rapamycin or paclitaxel combined with cytokine antibody for 48 hours.

RESULTS

After incubation of HASMC with ox-LDL, the ratios of cholesterol ester and total cholesterol increased significantly (55.29%) (P<0.01). Lipid staining with Oil Red O showed many lipid vacuoles and red dye particles in the cells. Meanwhile, cell viability and proliferation significantly increased compared with the control. This indicated that HASMC had been transformed into foam cells (P<0.01) while rapamycin or paclitaxel concentrations ≥0.1 µg/mL can significantly decrease the foam cell proliferation (P<0.05 or P<0.01), and 1 µg/mL of rapamycin or paclitaxel appeared the most effective concentration. As for cytokines, rapamycin or paclitaxel concentrations ≥1 ug/mL could significantly increase the level of inflammatory cytokines IL-6 (P<0.05 or P<0.01), which was enhanced with the increase of drug concentration. However, rapamycin or paclitaxel concentrations ≥1 µg/mL could significantly reduce the levels of anti-inflammatory cytokines IL-35 and transforming growth factor beta (TGF-β) (P<0.05 or P<0.01), which decreased with the increase of drug concentration. In addition, rapamycin or paclitaxel combined with anti-IL-1β, anti-IL-6, anti- TNF-α or anti-IL-35 had no significant effect on foam cell proliferation compared to the drug alone. However, rapamycin or paclitaxel combined with anti-IL-10 or anti-TGF-β can significantly enhance foam cell proliferation (P<0.01). In addition, there was no difference in the effects of the same concentrations of rapamycin and paclitaxel on foam cells.

CONCLUSION

Although rapamycin or paclitaxel can reduce foam cell proliferation, too high or too low concentrations could decrease effectiveness. In particular, a high dose can induce foam cells to increase inflammatory cytokines secretion, reduce anti-inflammatory cytokines secretion, and thus affect the inhibiting proliferation. For rapamycin- and paclitaxel-eluting stents, this conclusion may explain the clinical observation of in-stent restenosis after percutaneous coronary intervention. DES coated with an appropriate concentration of rapamycin or paclitaxel may, at least to some extent, contribute significantly to reducing incidence of late in-stent restenosis.

Slow-flow phenomena following lower limb paclitaxel- and sirolimus-coated balloon angioplasty in the setting of chronic limb threatening ischaemia-a case series

The Achilles heel of plain old balloon angioplasty (POBA) is neointimal hyperplasia (NIH) and restenosis, caused from the barotrauma of ballooning. Drug-coated balloons using a paclitaxel-based platform (PCB) have been shown to retard the restenotic process, using the anti-proliferative effects of paclitaxel, and give longer vessel patency. This is important in the setting of chronic limb threatening ischemia (CLTI) and for the protracted wound healing process in these frail patients. However, during PCB application, more than 50% of the drug is lost downstream, a phenomenon termed particulate embolization. This is thought to account for the slow- or no-flow phenomenon encountered after PCB use. Recent data suggest that slow-flow phenomenon was associated with a lower target lesion revascularisation rate and worse amputation free survival (AFS). The use of sirolimus coated balloons (SCB) to impede the NIH cascade has been less well studied but recent data suggested excellent short-term efficacy and found no slow flow phenomenon with their use in the tibial arteries in CLTI patients. Aim of this case series is to highlight the difference in flow phenomena using PCB and SCB elution in the setting of CLTI. We evaluated the use of parametric colour coding and time attenuation curves (TAC) as a quantitative measure of blood flow. SCB may have an advantage over PCB use in the peripheral vasculature because of a reduced incidence of slow flow phenomenon following drug elution.

MagicTouch PTA Sirolimus Coated Balloon for Femoropopliteal and Below the Knee Disease: Results From XTOSI Pilot Study Up To 12 Months

INTRODUCTION

Sirolimus coated balloon (SCB) is a promising treatment option to prevent restenosis for peripheral arterial occlusive disease (PAOD). This is a pilot first-in-human study of MagicTouch percutaneous transluminal angioplasty (PTA) SCB for treatment of PAOD for both femoropopliteal and below the knee arteries (BTK).

MATERIAL AND METHODS

Xtreme Touch-Neo [MagicTouch PTA] Sirolimus Coated Balloon (XTOSI) pilot study is a prospective, single-arm, open-label, single-center trial evaluating MagicTouch PTA SCB for symptomatic PAOD. Primary endpoint was defined as primary patency at 6 months (duplex ultrasound peak systolic velocity ratio ≤2.4). Secondary endpoints included clinically driven target lesion revascularization (CD-TLR), amputation free survival (AFS), all-cause mortality, and limb salvage success.

RESULTS

Fifty patients were recruited. The mean age was 67 (n=31 [62%] males). SCB was applied to femoropopliteal in 20 patients (40%) and BTK in 30 patients (60%). Majority of treatments (94%) were performed for limb salvage indications (Rutherford scores 5 or 6). This was a high risk cohort, in which 90% had diabetes, 36% had coronary artery disease, 20% had end stage renal failure, and American Society of Anaesthesiologists (ASA) score was 3 or more in 80%. Mean lesion length treated was 227±81 mm, of which 36% were total occlusions. Technical and device success were both 100%. At 30 days, mortality was 2% and major limb amputation was also 2%. Six-month primary patency was 80% (88.2% for femoropopliteal; 74% for BTK). At 12 months, freedom from CD-TLR was 89.7% (94.1% for femoropopliteal; 86.3% for BTK), AFS was 81.6% (90.0% for femoropopliteal; 75.9% for BTK), all-cause mortality was 14.3% (10.0% for femoropopliteal; 17.2% for BTK), and limb salvage success was 92.9% (94.4% for femoropopliteal; 91.7% for BTK). There was a statistically significant increase between baseline and 6-month toe pressures for both femoropopliteal (57.3±23.3 mm Hg vs 82.5±37.8 mm Hg; p<.001) and BTK lesions (52.8±19.2 mm Hg vs 70.7±37 mm Hg; p<.037). At 12 months, wound healing rate was 33/39 (84.6%).

CONCLUSIONS

MagicTouch PTA SCB in the XTOSI study showed promising 6-month primary patency and encouraging 12-month freedom from CD-TLR, AFS, and limb salvage rates. No early safety concerns were raised. Randomized trials are needed to investigate the safety and efficacy of SCB for treatment of PAOD.

Nanoparticles eluting stents for coronary intervention: Formulation, characterization and in vitro evaluation

Coronary artery disease (CAD) is currently a leading cause of death worldwide. In the history of percutaneous coronary intervention for the treatment of CAD, a drug-eluting stent (DES) is recognized as a revolutionary technology that has the unique ability to significantly reduce restenosis and provide both mechanical and biological solutions simultaneously to the target lesion. The aim of the research work was to design and fabricate DES coated with a nanoparticulate drug formulation. Sirolimus, an inhibitor of the smooth muscle cell (SMC) proliferation and migration, was encapsulated in polymeric nanoparticles. The nanoparticle formulation was characterized for various physicochemical parameters. Cell viability and cell uptake studies were performed using human coronary artery smooth muscle cells (HCASMCs). The developed nanoparticle formulation showed enhanced efficacy compared to plain drug solution and exhibited time-dependent uptake into the HCASMCs. The developed nanoparticle formulation was coated on the FlexinniumTM ultra-thin cobalt-chromium alloy coronary stent platform. The nanoparticle coated stents were characterized for morphology and residual solvent analysis. In-vitro drug release was also evaluated. Ex-vivo arterial permeation was carried out to evaluate the nanoparticle uptake from the surface of the stents. The characterization studies together corroborated that the developed nanoparticle coated stent can be a promising replacement of the current drug-eluting stents.

Targeting Autophagy with Natural Compounds in Cancer: A Renewed Perspective from Molecular Mechanisms to Targeted Therapy

Natural products are well-characterized to have pharmacological or biological activities that can be of therapeutic benefits for cancer therapy, which also provide an important source of inspiration for discovery of potential novel small-molecule drugs. In the past three decades, accumulating evidence has revealed that natural products can modulate a series of key autophagic signaling pathways and display therapeutic effects in different types of human cancers. In this review, we focus on summarizing some representative natural active compounds, mainly including curcumin, resveratrol, paclitaxel, Bufalin, and Ursolic acid that may ultimately trigger cancer cell death through the regulation of some key autophagic signaling pathways, such as RAS-RAF-MEK-ERK, PI3K-AKT-mTOR, AMPK, ULK1, Beclin-1, Atg5 and p53. Taken together, these inspiring findings would shed light on exploiting more natural compounds as candidate small-molecule drugs, by targeting the crucial pathways of autophagy for the future cancer therapy.

[Innovations in the endovascular treatment of peripheral arterial disease]

The cooperation of physicians, engineers and other sciences results in a steady launching of effective tools for vascular treatment, which further support the dominating position of endovascular therapy in the field of PAD. Parallel to the treatment options, non-radiation based image guidance is another area, where innovation helps to reduce radiation burden for patient and staff members without losing procedural quality and despite a growing number of radiation based procedures. Meanwhile, the available portfolio of endovascular tools allows to treat every vessel segment with results comparable to or even better then open surgery. This survey presents new techniques, tools and recently published results from related trials, which will probably have further influence on PAD treatment in the coming years.

Drug-Coated Balloon for Arteriovenous Access Stenosis in Hemodialysis Patients

Hemodialysis access stenosis is a pervasive problem that occurs due to the physiology of the high-flow circuit. Stenosis occurs due to endothelial and smooth muscle injuries that result in neointimal hyperplasia. Percutaneous transluminal angioplasty is the standard treatment for dialysis access-induced stenosis. Unfortunately, it is also associated with vessel wall trauma, which causes further intimal hyperplasia and restenosis. Data from randomized controlled trials (RCTs) and systematic reviews of the use of drug-coated balloons (DCBs) for dialysis access stenosis have been controversial. While several single-center trials or RCTs have reported safe and effective use of DCBs, conflicting results still exist. Furthermore, paclitaxel is known to be associated with an increased mortality risk. Herein, we review the current evidence on the role of DCBs in the treatment of dialysis access stenosis.

Impact of diabetes mellitus on vascular healing process after everolimus-eluting stent implantation: An optical coherence tomography study

BACKGROUND/PURPOSE

To study the impact of diabetes mellitus (DM) on vascular healing process after implantation of everolimus-eluting stent (EES).

METHODS/MATERIALS

Data from 3 prospective studies (HEAL-EES, REVER, and RESERVOIR), including patients with EES implantation and OCT follow-up, were merged. Differences in vascular healing process assessed by OCT were compared between DM and non-DM using generalized estimating equations. Neointimal proliferation, neointimal signal pattern (high, low, and layered), and uncovered/malapposed struts were evaluated.

RESULTS

A total of 96 lesions (61 DM lesions and 35 non-DM lesions) were included. Mean OCT follow-up time was 8.9 ± 1.5 months and comparable between groups. DM were older, high frequently female and acute coronary syndrome, and received smaller stent than non-DM. No differences were observed in quantitative vascular healing process between groups. However, DM exhibited higher low and layered signal pattern neointima compared to non-DM at lesion level (p = 0.030) and cross-section level (p < 0.001). Uncovered/malapposed struts were comparable between groups.

CONCLUSIONS

Quantitative vascular healing process was comparable between groups. However, DM was significantly associated with low signal pattern, which is characteristic of focal inflammation, after EES implantation. Further study might be required to study relationship between neointimal signal pattern and clinical events.

World's First Experience Treating TASC II C and D Tibial Occlusive Disease Using the Selution SLR Sirolimus-Eluting Balloon: Six-Month Results From the PRESTIGE Study

Purpose:

The performance of sirolimus-coated devices has not been studied in patients with chronic limb-threatening ischemia patients. PRESTIGE aims to investigate the 6-month efficacy and safety profile of the Selution Sustained Limus Release (SLR) sirolimus-eluting balloon for treatment of TASC II C and D tibial occlusive lesions in patients with CLTI.

Materials and Methods:

PRESTIGE is a pilot prospective, nonrandomized, single-arm, multi-investigator, single-center clinical study. Endpoints were adverse event-free survival at 1 month, technical success rate, primary tibial patency at 6 months, limb salvage success, target lesion revascularization (TLR), and amputation free survival (AFS).

Results:

A total of 25 patients were included. There were 17 (68.0%) males; mean age, 63.7±9.73 years. CLTI severity was based on the Rutherford scale (R5=25/25; 100.0%). Significant comorbidities included diabetes mellitus (n=22; 88.0%) and end-stage renal failure (n=11; 44.0%). A total of 33 atherosclerotic lesions were treated (TASC II D=15 (45.5%)). Mean lesion length treated was 191±111 mm. Technical success was 100%. Primary tibial patency at 6 months was 22/27 (81.5%) and freedom from clinically driven TLR was 25/30 (83.3%). AFS was 21/25 (84.0%; 3 deaths and 1 major lower extremity amputation). Mean Rutherford score improved from 5.00 at baseline to 1.14±2.10 (p<0.05) at 6 months. There was a wound healing rate of 13/22 (59.1%) and 17/21 (81.0%) at 3 and 6 months respectively.

Conclusions:

Selution SLR drug-eluting balloon is a safe and efficacious modality in treating complex tibial arterial occlusive lesions in what is an otherwise frail cohort of CLTI patients, with a high prevalence of diabetes and end-stage renal failure. Technical and clinical success rates are high and 6-month target lesion patency and AFS are more than satisfactory.

Do we really understand how drug eluted from stents modulates arterial healing?

The advent of drug-eluting stents (DES) has revolutionised the treatment of coronary artery disease. These devices, coated with anti-proliferative drugs, are deployed into stenosed or occluded vessels, compressing the plaque to restore natural blood flow, whilst simultaneously combating the evolution of restenotic tissue. Since the development of the first stent, extensive research has investigated how further advancements in stent technology can improve patient outcome. Mathematical and computational modelling has featured heavily, with models focussing on structural mechanics, computational fluid dynamics, drug elution kinetics and subsequent binding within the arterial wall; often considered separately. Smooth Muscle Cell (SMC) proliferation and neointimal growth are key features of the healing process following stent deployment. However, models which depict the action of drug on these processes are lacking. In this article, we start by reviewing current models of cell growth, which predominantly emanate from cancer research, and available published data on SMC proliferation, before presenting a series of mathematical models of varying complexity to detail the action of drug on SMC growth in vitro. Our results highlight that, at least for Sodium Salicylate and Paclitaxel, the current state-of-the-art nonlinear saturable binding model is incapable of capturing the proliferative response of SMCs across a range of drug doses and exposure times. Our findings potentially have important implications on the interpretation of current computational models and their future use to optimise and control drug release from DES and drug-coated balloons.

Paclitaxel- and Sirolimus-coated Balloons in Peripheral Artery Disease Treatment: Current Perspectives and Concerns

Drug-coated balloons (DCBs) have become an established therapy for the treatment of above-the-knee peripheral artery disease. The paclitaxel DCB has shown clinical benefit in terms of patency and freedom from re-intervention in multiple randomised trials. However, a recent meta-analysis has suggested an association between mortality and the use of paclitaxel-coated devices. Sirolimus is another potential choice of anti-proliferative agent for use in DCBs because of its wider therapeutic index and lower risk for dose-dependent toxicity. More recently, encapsulating sirolimus in micro-reservoirs or polymers has facilitated the development of effective sirolimus DCBs, some of which are available in Europe and Asia. In this review, the authors focus on paclitaxel and sirolimus DCB technologies from the standpoint of drug characteristics and clinical trials.

Significant difference between sirolimus and paclitaxel nanoparticles in anti-proliferation effect in normoxia and hypoxia: The basis of better selection of atherosclerosis treatment

Compared with paclitaxel, sirolimus has been more used in the treatment of vascular restenosis gradually as an anti-proliferative drug, but few basic studies have elucidated its mechanism. The anti-proliferative effects of sirolimus or paclitaxel have been demonstrated by numerous studies under normoxia, but few studies have been achieved focusing hypoxia. In this study, porcine carotid artery injury model and classical cobalt chloride hypoxia cell model were established. Sirolimus nanoparticles (SRM-NPs), paclitaxel nanoparticles (PTX-NPs) and blank nanoparticles (Blank-NPs) were prepared respectively. The effect of RPM-NPs on the degree of stenosis, proliferative index and the expression of PCNA after 28 days of porcine carotid artery injury model was evaluated. Compared with saline group and SRM groups, SRM-NPs group suppressed vascular stenosis, proliferative index and the expression of PCNA (P < 0.01 and P < 0.05). Endothelial cell (EC) and smooth muscle cell (SMC) were pre-treated with cobaltous chloride, followed by SRM-NPs, PTX-NPs, Blank-NPs or PBS control treating, the effects on cell proliferation, HIF-1 expression and glycolysis were detected. SRM-NPs could inhibit EC and SMC proliferation under hypoxia, while PTX-NPs couldn't (P < 0.001). Significant differences between sirolimus and paclitaxel NPs in anti-proliferation effect under normoxia and hypoxia may due to the different inhibitory effects on HIF-1α expression and glycolysis. In conclusion, these results suggest that sirolimus can inhibit the proliferation of hypoxic cells more effectively than paclitaxel. These observations may provide a basis for understanding clinical vascular stenosis therapeutic differences between rapamycin and paclitaxel.

Influence of Drug Incorporation on the Physico-Chemical Properties of Poly(l-Lactide) Implant Coating Matrices-A Systematic Study

Local drug delivery has become indispensable in biomedical engineering with stents being ideal carrier platforms. While local drug release is superior to systemic administration in many fields, the incorporation of drugs into polymers may influence the physico-chemical properties of said matrix. This is of particular relevance as minimally invasive implantation is frequently accompanied by mechanical stresses on the implant and coating. Thus, drug incorporation into polymers may result in a susceptibility to potentially life-threatening implant failure. We investigated spray-coated poly-l-lactide (PLLA)/drug blends using thermal measurements (DSC) and tensile tests to determine the influence of selected drugs, namely sirolimus, paclitaxel, dexamethasone, and cyclosporine A, on the physico-chemical properties of the polymer. For all drugs and PLLA/drug ratios, an increase in tensile strength was observed. As for sirolimus and dexamethasone, PLLA/drug mixed phase systems were identified by shifted drug melting peaks at 200 °C and 240 °C, respectively, whereas paclitaxel and dexamethasone led to cold crystallization. Cyclosporine A did not affect matrix thermal properties. Altogether, our data provide a contribution towards an understanding of the complex interaction between PLLA and different drugs. Our results hold implications regarding the necessity of target-oriented thermal treatment to ensure the shelf life and performance of stent coatings.

[Use of drug-coated balloons for interventions on bifurcation lesions of coronary arteries]

Interventions on bifurcation lesions of the coronary bed are one of the most complicated tasks of interventional cardiology. Recent trends are toward active study of using drug-eluting balloons for interventions in this type of lesions. Using such technique makes it possible to minimize the risks associated with implantation of stents in sites of coronary artery bifurcations with good angiographic results. This article is a review of the literature data concerning the use of drug-coated balloons in interventions on bifurcation lesions of the coronary bed, discussing peculiarities of the balloon catheter design, dynamics of delivery of an antiproliferative drug to the vascular wall. This is followed by considering the experience with using innovative sirolimus-coated balloon catheters, as well as future perspectives of these devices for interventions in coronary artery bifurcation lesions.

Early (6 months) results of a pilot prospective study to investigate the efficacy and safety of sirolimus coated balloon angioplasty for dysfunctional arterio-venous fistulas: MAgicTouch Intervention Leap for Dialysis Access (MATILDA) Trial

Background

The aim of this pilot study was to evaluate the safety and efficacy of the MagicTouch™ sirolimus-coated balloon (SCB) catheter (Concept Medical Inc., Tampa, FL, US) on improving the patency of failing arterio-venous fistulas (AVF) with de novo and recurrent stenoses. MATILDA reports early outcomes at 3- and 6 months post intervention.

Methods

Single-centre, single-arm prospective pilot study of 33 (18 males; mean age 64.7±11.6 years) end-stage renal failure Asian patients with a dysfunctional AVF, who underwent SCB angioplasty between May 2019-January 2020. All procedures were performed under local anaesthetic without sedation and as day surgery. All patients were prescribed dual antiplatelet therapy for 3 months and followed up with Duplex ultrasound at 3 and 6 months.

Results

47 stenotic target lesions treated and 24/33 (72.7%) patients were for restenosis. Main indications for intervention was low/dropping access flow (21/33; 63.6%) and most common target lesion was in the juxta-anastomosis (19/47; 40.4%). There was 100% technical and procedural success. There were no peri-procedural complications related to the SCB. The target lesion primary patency rates at 3 and 6 months were 46/47 (97.9%) and 29/35 (82.9%) respectively. Circuit access patency rates at 3 and 6 months were 31/33 (93.9%) and 17/25 (68%) respectively. There was one (2.9%) death at 6 months and 4/33 (12.1%) overall to date, all from patients’ underlying co-morbidities.

Conclusions

SCB angioplasty for dysfunctional AVF circuits is a safe and efficacious modality in Asian haemodialysis patients at six months comparable if not better than the paclitaxel data reported to date in the literature.

Six-Month Outcomes From the First-in-Human, Single-Arm SELUTION Sustained-Limus-Release Drug-Eluting Balloon Trial in Femoropopliteal Lesions

Purpose: To evaluate the safety and efficacy of the novel SELUTION sustained-limus-release (SLR) drug-eluting balloon (DEB) in the treatment of femoropopliteal lesions. Materials and Methods: Between October 2016 and May 2017, 50 subjects (mean age 69.6±10.4 years; 29 men) with symptomatic moderate to severe lower limb ischemia (Rutherford categories 2 or 3) were enrolled at 4 German centers for the SELUTION SLR first-in-human trial (ClinicalTrials.gov NCT02941224). The SELUTION SLR utilizes micro-reservoirs (biodegradable polymer spheres containing sirolimus) embedded within an amphipathic membrane coated onto an angioplasty balloon. The biodegradable reservoirs are transferred to the target vessel lumen during brief balloon inflation. The primary trial objective was comparison of angiographic late lumen loss at 6 months against an objective performance criterion (OPC) value of 1.04 mm for uncoated balloon angioplasty. Secondary endpoints included device, procedural, and clinical success; clinical and imaging assessments of primary patency and restenosis; functional assessments including Rutherford category and ankle-brachial index (ABI); and major adverse events [composite of cardiovascular mortality, index limb amputation, target limb thrombosis, and clinically-driven target lesion revascularization (CD-TLR)]. Results: At 6 months, median angiographic late lumen loss following SELUTION SLR treatment was 0.19 mm (range -1.16 to 3.07). Mean angiographic late lumen loss (n=34) was 0.29±0.84 mm (95% CI -0.01 to 0.58), significantly lower than the 1.04-mm OPC value (p<0.001). The rate of primary patency by duplex ultrasound was 88.4%, and freedom from angiographic binary restenosis was 91.2%. Through 6 months, there was significant improvement over baseline in Rutherford categories (p<0.001) and in ABI measurements (p<0.001). A single case (2%) of CD-TLR occurred at 5 months. There were no other major adverse events. Conclusion: Through 6 months, the SELUTION SLR DEB appears to inhibit restenosis effectively and safely, improving outcomes in subjects with symptomatic femoropopliteal disease.

The SELUTION SLR™ drug-eluting balloon system for the treatment of symptomatic femoropopliteal lesions

Endovascular treatment has become first line therapy for the treatment of femoropopliteal disease. Drug-coated devices play a key role in maintaining vessel patency. In the past antiproliferative coating of drug-coated balloons (DCBs) exclusively consisted of paclitaxel. Use of limus drugs was limited by a short residency time in the vessel wall. Besides the drug, the SELUTION SLR™ drug-eluting balloon system consists of a coating formulation of four excipients. The first excipient is a biodegradable polymer (poly(lactic-co-glycolic acid)) that is intermixed with the sirolimus to form micro-reservoirs and regulates drug release via matrix degradation. This review summarizes the existing pre-clinical and clinical literature on treatment of femoropopliteal artery lesions with the SELUTION SLR DCB.