Development of a novel prohealing stent designed to deliver sirolimus from a biodegradable abluminal matrix

Surface modification of neurovascular stents: from bench to patient

Flow-diverting stents (FDs) for the treatment of cerebrovascular aneurysms are revolutionary. However, these devices require systemic dual antiplatelet therapy (DAPT) to reduce thromboembolic complications. Given the risk of ischemic complications as well as morbidity and contraindications associated with DAPT, demonstrating safety and efficacy for FDs either without DAPT or reducing the duration of DAPT is a priority. The former may be achieved by surface modifications that decrease device thrombogenicity, and the latter by using coatings that expedite endothelial growth. Biomimetics, commonly achieved by grafting hydrophilic and non-interacting polymers to surfaces, can mask the device surface with nature-derived coatings from circulating factors that normally activate coagulation and inflammation. One strategy is to mimic the surfaces of innocuous circulatory system components. Phosphorylcholine and glycan coatings are naturally inspired and present on the surface of all eukaryotic cell membranes. Another strategy involves linking synthetic biocompatible polymer brushes to the surface of a device that disrupts normal interaction with circulating proteins and cells. Finally, drug immobilization can also impart antithrombotic effects that counteract normal foreign body reactions in the circulatory system without systemic effects. Heparin coatings have been explored since the 1960s and used on a variety of blood contacting surfaces. This concept is now being explored for neurovascular devices. Coatings that improve endothelialization are not as clinically mature as anti-thrombogenic coatings. Coronary stents have used an anti-CD34 antibody coating to capture circulating endothelial progenitor cells on the surface, potentially accelerating endothelial integration. Similarly, coatings with CD31 analogs are being explored for neurovascular implants.

Dual-therapy CD34 antibody-covered sirolimus-eluting COMBO stents versus sirolimus-eluting Orsiro stents in patients treated with percutaneous coronary intervention: the three-year outcomes of the SORT OUT X randomised clinical trial

BACKGROUND

Target lesion failure (TLF) remains an issue with contemporary drug-eluting stents. The dual-therapy sirolimus-eluting and CD34 antibody-coated COMBO stent (DTS) was designed to improve early healing.

AIMS

We aimed to compare the 3-year outcomes of the DTS and the sirolimus-eluting Orsiro stent (SES) in all-comer patients treated with percutaneous coronary intervention.

METHODS

The SORT OUT X trial is a prospective multicentre randomised clinical trial with a registry-based follow-up comparing DTS and SES. The primary endpoint, TLF, is a composite of cardiac death, myocardial infarction or target lesion revascularisation (TLR).

RESULTS

A total of 3,146 patients were randomised to treatment with the DTS (1,578 patients) or the SES (1,568 patients). At 3 years, an intention-to-treat analysis showed that 155 patients (9.8%) who were assigned the DTS and 118 patients (7.5%) who were assigned the SES met the primary endpoint (incidence rate ratio for TLF=1.33, 95% confidence interval: 1.04-1.70; p=0.02). This difference was caused by a significantly higher TLF rate in the DTS group compared to the SES group within the first year, which was mainly explained by a higher incidence of TLR in the DTS group compared to the SES group. Of note, the TLF rates were almost identical from 1 year to 3 years in both stent groups.

CONCLUSIONS

At 3 years, the SES was superior to the DTS, mainly because the DTS was associated with an increased risk of TLF within the first year but not from 1 to 3 years.

CLINICALTRIALS

gov: NCT03216733.

In-stent restenosis after percutaneous coronary intervention: emerging knowledge on biological pathways

Percutaneous coronary intervention (PCI) has evolved significantly over the past four decades. Since its inception, in-stent restenosis (ISR)-the progressive reduction in vessel lumen diameter after PCI-has emerged as the main complication of the procedure. Although the incidence of ISR has reduced from 30% at 6 months with bare-metal stents to 7% at 4 years with drug-eluting stents (DESs), its occurrence is relevant in absolute terms because of the dimensions of the population treated with PCI. The aim of this review is to summarize the emerging understanding of the biological pathways that underlie ISR. In-stent restenosis is associated with several factors, including patient-related, genetic, anatomic, stent, lesion, and procedural characteristics. Regardless of associated factors, there are common pathophysiological pathways involving molecular phenomena triggered by the mechanical trauma caused by PCI. Such biological pathways are responses to the denudation of the intima during balloon angioplasty and involve inflammation, hypersensitivity reactions, and stem cell mobilization particularly of endothelial progenitor cells (EPCs). The results of these processes are either vessel wall healing or neointimal hyperplasia and/or neo-atherosclerosis. Unravelling the key molecular and signal pathways involved in ISR is crucial to identify appropriate therapeutic strategies aimed at abolishing the 'Achille's heel' of PCI. In this regard, we discuss novel approaches to prevent DES restenosis. Indeed, available evidence suggests that EPC-capturing stents promote rapid stent re-endothelization, which, in turn, has the potential to decrease the risk of stent thrombosis and allow the use of a shorter-duration dual antiplatelet therapy.

Rectifying disorder of extracellular matrix to suppress urethral stricture by protein nanofilm-controlled drug delivery from urinary catheter

Urethral stricture secondary to urethral injury, afflicting both patients and urologists, is initiated by excessive deposition of extracellular matrix in the submucosal and periurethral tissues. Although various anti-fibrotic drugs have been applied to urethral stricture by irrigation or submucosal injection, their clinical feasibility and effectiveness are limited. Here, to target the pathological state of the extracellular matrix, we design a protein-based nanofilm-controlled drug delivery system and assemble it on the catheter. This approach, which integrates excellent anti-biofilm properties with stable and controlled drug delivery for tens of days in one step, ensures optimal efficacy and negligible side effects while preventing biofilm-related infections. In a rabbit model of urethral injury, the anti-fibrotic catheter maintains extracellular matrix homeostasis by reducing fibroblast-derived collagen production and enhancing metalloproteinase 1-induced collagen degradation, resulting in a greater improvement in lumen stenosis than other topical therapies for urethral stricture prevention. Such facilely fabricated biocompatible coating with antibacterial contamination and sustained-drug-release functionality could not only benefit populations at high risk of urethral stricture but also serve as an advanced paradigm for a range of biomedical applications.

Impact of acute coronary syndrome on clinical outcomes after revascularization with the dual-therapy CD34 antibody-covered sirolimus-eluting Combo stent and the sirolimus-eluting Orsiro stent

OBJECTIVES

To compare the efficacy and safety of the dual-therapy CD34 antibody-covered sirolimus-eluting Combo stent (DTS) and the sirolimus-eluting Orsiro stent (O-SES) in patients with and without acute coronary syndrome (ACS) included in the SORT OUT X study.

BACKGROUND

The incidence of target lesion failure (TLF) after treatment with modern drug-eluting stents has been reported to be significantly higher in patients with ACS when compared to patients without ACS. Whether the results from the SORT OUT X study apply to patients with and without ACS remains unknown.

METHODS

In total, 3146 patients were randomized to stent implantation with DTS (n = 1578; ACS: n = 856) or O-SES (n = 1568; ACS: n = 854). The primary end point, TLF, was a composite of cardiac death, target-lesion myocardial infarction (MI), or target lesion revascularization (TLR) within 1 year.

RESULTS

At 1 year, the rate of TLF was higher in the DTS group compared to the O-SES group, both among patients with ACS (6.7% vs. 4.1%; incidence rate ratio: 1.65 [95% confidence interval, CI: 1.08-2.52]) and without ACS (6.0% vs. 3.2%; incidence rate ratio: 1.88 [95% CI: 1.13-3.14]). The differences were mainly explained by higher rates of TLR, whereas rates of cardiac death and target lesion MI did not differ significantly between the two stent groups in patients with or without ACS CONCLUSION: Compared to the O-SES, the DTS was associated with a higher risk of TLF at 12 months in patients with and without ACS. The differences were mainly explained by higher rates of TLR.

The mega COMBO collaboration: An individual patient data pooled analysis of patients undergoing PCI with COMBO stent

BACKGROUND

COMBO (OrbusNeich Medical, Hong Kong) is a dual-therapy coronary stent featuring sirolimus as antiproliferative drug and an anti-CD34+ antibody coating to attract endothelial progenitor cells favoring rapid stent re-endothelization. The Mega COMBO collaboration aimed to evaluate the performance of the COMBO stent in a large contemporary cohort of patients undergoing percutaneous coronary intervention (PCI).

METHODS

Patient-level data of subjects undergoing PCI with the COMBO stent from the REMEDEE-Trial, REMEDEE-OCT, HARMONEE, REDUCE, SORT OUT X, REMEDEE-Registry and MASCOT studies were pooled together. The primary endpoint was 1-year target lesion failure (TLF), a composite of cardiovascular death, target vessel myocardial infarction (TV-MI) or clinically driven target lesion revascularization (CD-TLR). Secondary outcomes were the individual components of the primary endpoint and stent thrombosis (ST). Endpoints were evaluated against performance goals based on the EAPCI (the European Association of Percutaneous Coronary Intervention) recommendations for new drug-eluting stents.

RESULTS

A total of 6753 patients (mean age 63.7 ± 11.4 years, 23% women) were included. At 1-year follow-up, TLF occurred in 303 (4.6%) patients. The rates of cardiovascular death, TV-MI, and CD-TLR were 1.3%, 1.8%, and 2.5%, respectively. The rate of definite/probable ST was 0.73%, early ST (<1 month) was 0.48%, while late ST (1-12 months) was 0.26%. The performance goals were met for all of the evaluated endpoints.

CONCLUSIONS

This large patient-level pooled analysis provides a comprehensive outline of the performance of the dual-therapy COMBO stent. The low rates of primary and secondary endpoints suggest that this stent technology may be a good alternative to other contemporary drug eluting coronary stent platforms.

Biofunctionalization of cardiovascular stents to induce endothelialization: Implications for in- stent thrombosis in diabetes

Stent thrombosis remains one of the main causes that lead to vascular stent failure in patients undergoing percutaneous coronary intervention (PCI). Type 2 diabetes mellitus is accompanied by endothelial dysfunction and platelet hyperactivity and is associated with suboptimal outcomes following PCI, and an increase in the incidence of late stent thrombosis. Evidence suggests that late stent thrombosis is caused by the delayed and impaired endothelialization of the lumen of the stent. The endothelium has a key role in modulating inflammation and thrombosis and maintaining homeostasis, thus restoring a functional endothelial cell layer is an important target for the prevention of stent thrombosis. Modifications using specific molecules to induce endothelial cell adhesion, proliferation and function can improve stents endothelialization and prevent thrombosis. Blood endothelial progenitor cells (EPCs) represent a potential cell source for the in situ-endothelialization of vascular conduits and stents. We aim in this review to summarize the main biofunctionalization strategies to induce the in-situ endothelialization of coronary artery stents using circulating endothelial stem cells.

Endothelial Progenitor Cells in Coronary Artery Disease: From Bench to Bedside

Endothelial progenitor cells (EPCs) are a heterogeneous group of cells present in peripheral blood at various stages of endothelial differentiation. EPCs have been extensively investigated in patients with coronary artery disease (CAD), with controversial findings both on their role in atherosclerosis progression and in the process of neointimal growth after a percutaneous coronary intervention (PCI). Despite nearly 2 decades of experimental and clinical investigations, however, the significance of EPCs in clinical practice remains unclear and poorly understood. This review provides an update on the role of EPCs in the most common clinical scenarios that are experienced by cardiologists managing patients with CAD. We here summarize the main findings on the association of EPCs with cardiovascular risk factors, coronary atherosclerosis, and myocardial ischemia. We then discuss the potential effects of EPCs in post-PCI in-stent restenosis, as well as most recent findings with EPC-coated stents. Based on the mounting evidence of the relationship between levels of EPCs and several different adverse cardiovascular events, EPCs are emerging as novel predictive biomarkers of long-term outcomes in patients with CAD.

Impact of diabetes on clinical outcomes after revascularization with the dual therapy CD34 antibody-covered sirolimus-eluting Combo stent and the sirolimus-eluting Orsiro stent

OBJECTIVES

To compare the efficacy and safety of the dual therapy CD34 antibody-covered sirolimus-eluting Combo stent (DTS) and the sirolimus-eluting Orsiro stent (SES) in patients with and without diabetes mellitus (DM) included in the Scandinavian Organization for Randomized Trials with Clinical Outcome (SORT OUT) X study.

BACKGROUND

The incidence of target lesion failure (TLF) after treatment with modern drug-eluting stents has been reported to be significantly higher in patients with DM when compared to patients without DM. Thus, whether the results from the SORT OUT X study apply to patients with and without DM remains unknown.

METHODS

In total 3146 patients were randomized to stent implantation with DTS (n = 1578; DM: n = 279) or SES (n = 1568; DM: n = 271). The primary end point, TLF, was a composite of cardiac death, target-lesion myocardial infarction (MI), or target lesion revascularization (TLR) within 1 year.

RESULTS

At 1 year, the rate of TLF was increased in the DTS group compared to the SES group, both among patients with DM (9.3% vs. 4.8%; risk difference: 4.5%; incidence rate ratio: 1.99, 95% confidence interval [CI]: 1.02-3.90) and without DM (5.7% vs. 3.5%; incidence rate ratio: 1.67, 95% CI: 1.15-2.42). The differences were mainly explained by higher rates of TLR.

CONCLUSION

Compared to the SES, the DTS was associated with an increased risk of TLF at 12 months in patients with and without DM. The differences were mainly explained by higher rates of TLR, whereas rates of cardiac death and target lesion MI did not differ significantly between the two stent groups in patients with or without DM.

Nine-month angiographic and 2-year clinical outcomes of the RECOVERY trial: A randomized study of the biodegradable polymer sirolimus-eluting COMBO dual-therapy stent versus a polymer-free sirolimus-eluting stent in Chinese patients

OBJECTIVES

We evaluated the safety and efficacy of the novel dual-therapy sirolimus-eluting and endothelial progenitor cell (EPC) capture COMBO stent.

BACKGROUND

(Very) late stent thrombosis (ST) and neo-atherosclerosis limit the performance of drug-eluting stents. The capture of EPCs accelerates stent re-endothelialization, thereby potentially decreasing the risk of restenosis and ST.

METHODS

In total, 440 patients with de novo lesions in native coronary arteries were randomized (1:1) to either receive the COMBO stent (n = 220) or Nano polymer-free sirolimus-eluting stent (n = 220). The primary endpoint was the 9-month angiographic in-segment late lumen loss (LLL). Secondary endpoints included target lesion failure (TLF), a patient-oriented composite endpoint (PoCE), and ST.

RESULTS

At 9 months, the COMBO in-segment LLL (0.29 ± 0.46 mm) was non-inferior to that of the Nano comparator stent (0.31 ± 0.44 mm; p_{non-inferiority}  < .0001). Clinical outcomes were also similar between the COMBO and Nano stents, with TLF rates of 9.3% and 7.9% (p = .61) at 12 months, and 9.4% and 8.0% (p = .62) at 24 months, respectively. The PoCE rate was 14.8% and 10.6% (p = .19) at 12 months, and 16.0% and 11.3% (p = .16) at 24 months, respectively. Ischemia-driven target lesion revascularization rates were 6.0% and 3.7% (p = .26) at 12 months, and 6.2% and 3.8% (p = .26) at 24 months, respectively. No case of ST occurred in either group.

CONCLUSIONS

The RECOVERY trial has shown the COMBO stent was effective, meeting the primary non-inferiority angiographic endpoint, and safe, with an overall low rate of clinical events in both stent groups, including no ST for up to 2 years.

Randomized Clinical Comparison of the Dual-Therapy CD34 Antibody-Covered Sirolimus-Eluting Combo Stent With the Sirolimus-Eluting Orsiro Stent in Patients Treated With Percutaneous Coronary Intervention: The SORT OUT X Trial

BACKGROUND

Target lesion failure remains an issue with contemporary drug-eluting stents. Thus, the dual-therapy sirolimus-eluting and CD34+ antibody-coated Combo stent (DTS) was designed to further improve early healing. This study aimed to investigate whether the DTS is noninferior to the sirolimus-eluting Orsiro stent (SES) in an all-comers patient population.

METHODS

The SORT OUT X (Combo Stent Versus Orsiro Stent) trial, was a large-scale, randomized, multicenter, single-blind, 2-arm, noninferiority trial with registry-based follow-up. The primary end point target lesion failure was a composite of cardiac death, myocardial infarction, or target lesion revascularization within 12 months, analyzed using intention-to-treat. The trial was powered for assessing target lesion failure noninferiority of the DTS compared with the SES with a predetermined noninferiority margin of 0.021.

RESULTS

A total of 3146 patients were randomized to treatment with the DTS (1578 patients; 2008 lesions) or SES (1568 patients; 1982 lesions). At 12 months, intention-to-treat analysis showed that 100 patients (6.3%) assigned the DTS and 58 patients (3.7%) assigned the SES met the primary end point (absolute risk difference, 2.6% [upper limit of 1-sided 95% CI, 4.1%]; P (noninferiority)=0.76). The SES was superior to the DTS (incidence rate ratios for target lesion failure, 1.74 [95% CI, 1.26-2.41]; P=0.00086). The difference was explained mainly by a higher incidence of target lesion revascularization in the DTS group compared with the SES group (53 [3.4%] vs. 24 [1.5%]; incidence rate ratio, 2.22 [95% CI, 1.37-3.61]; P=0.0012).

CONCLUSIONS

The DTS did not confirm noninferiority to the SES for target lesion failure at 12 months in an all-comer population. The SES was superior to the DTS mainly because the DTS was associated with an increased risk of target lesion revascularization. However, rates of death, cardiac death, and myocardial infarction at 12 months did not differ significantly between the 2 stent groups. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03216733.

Sex differences in 1-year clinical outcomes after percutaneous coronary intervention with COMBO stents: From the COMBO collaboration

BACKGROUND

The COMBO drug eluting stent is a novel device with luminal endothelial progenitor cell capture technology for rapid homogeneous endothelialization.

METHODS AND RESULTS

We examined for sex differences in 1-year outcomes after COMBO stenting from the COMBO collaboration, a pooled patient-level dataset from the MASCOT and REMEDEE multicenter registries. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI), or clinically driven target lesion revascularization (CD-TLR). Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods. The study included 861 (23.8%) women and 2,753 (76.2%) men. Women were older with higher prevalence of several comorbidities including diabetes mellitus. Risk of 1-year TLF was similar in both sexes (3.8% vs. 3.9%, HR 0.92, 95% CI 0.59-1.42, p = .70), without sex differences in the incidence of cardiac death (1.6% vs. 1.5%, p = .78), TV-MI (1.5% vs. 1.1%, p = .32), or CD-TLR (2.0% vs. 2.2%, p = .67). Definite or probable ST occurred in 0.4% women and 1.0% men (HR 0.26, 95% CI 0.06-1.11, p = .069).

CONCLUSIONS

Despite greater clinical risks at baseline, women treated with COMBO stents had similarly low 1-year TLF and other ischemic outcomes compared to men.

Coronary endothelial and microvascular function distal to polymer-free and endothelial cell-capturing drug-eluting stents. The randomized FUNCOMBO trial

INTRODUCTION AND OBJECTIVES

The vasomotor function of new-generation drug-eluting stents designed to enhance stent healing and reendothelialization is unknown. This study aimed to compare the endothelial function of the infarct-related artery (IRA) treated with bioactive circulating endothelial progenitor cell-capturing sirolimus-eluting stents (COMBO) vs polymer-free biolimus-eluting stents (BioFreedom) in ST-segment elevation myocardial infarction patients at 6 months. Secondary objectives were to compare the microcirculatory function of the IRA and stent healing at 6 months.

METHODS

Sixty patients were randomized to bioactive sirolimus-eluting stent vs polymer-free biolimus-eluting stents implantation. At 6 months, patients underwent coronary angiography with vasomotor, microcirculatory and optical coherence tomography examinations. Endothelial dysfunction of the distal coronary segment was defined as ≥ 4% vasoconstriction to intracoronary acetylcholine infusion.

RESULTS

Endothelial dysfunction was similarly observed between groups (64.0% vs 62.5%, respectively; P=.913). Mean lumen diameter decreased by 16.0 ±20.2% vs 16.1 ±21.6% during acetylcholine infusion (P=.983). Microcirculatory function was similar in the 2 groups: coronary flow reserve was 3.23 ±1.77 vs 3.23±1.62 (P=.992) and the index of microcirculatory resistance was 24.8±16.8 vs 21.3±12.0 (P=.440). Optical coherence tomography findings were similar: uncovered struts (2.3% vs 3.2%; P=.466), malapposed struts (0.1% vs 0.3%; P=.519) and major evaginations (7.1% vs 5.6%; P=.708) were observed in few cases.

CONCLUSIONS

Endothelial dysfunction of the IRA was frequent and was similarly observed with new-generation drug-eluting stents designed to enhance stent reendothelialization at 6 months. Endothelial dysfunction was observed despite almost preserved microcirculatory function and complete stent coverage. Larger and clinically powered studies are needed to assess the role of residual endothelial dysfunction in ST-segment elevation myocardial infarction patients. Registered in ClinicalTrials.gov: NCT04202172.

One-Year COMBO Stent Outcomes in Acute Coronary Syndrome: from the COMBO Collaboration

PURPOSE

The COMBO biodegradable polymer sirolimus-eluting stent includes endothelial progenitor cell capture (EPC) technology for rapid endothelialization, which may offer advantage in acute coronary syndromes (ACS). We sought to analyze the performance of the COMBO stent by ACS status and ACS subtype.

METHODS

The COMBO collaboration (n = 3614) is a patient-level pooled dataset from the MASCOT and REMEDEE registries. We evaluated outcomes by ACS status, and ACS subtype in patients with ST segment elevation myocardial infarction (STEMI) or non-STEMI (NSTEMI) versus unstable angina (UA). The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization. Secondary outcomes included stent thrombosis (ST).

RESULTS

We compared 1965 (54%) ACS and 1649 (46.0%) non-ACS patients. ACS presentations included 40% (n = 789) STEMI, 31% (n = 600) NSTEMI, and 29% (n = 576) UA patients. Risk of 1-year TLF was greater in ACS patients (4.5% vs. 3.3%, HR 1.51 95% CI 1.01-2.25, p = 0.045) without significant differences in definite/probable ST (1.1% vs 0.5%, HR 2.40, 95% CI 0.91-6.31, p = 0.08). One-year TLF was similar in STEMI, NSTEMI, and UA (4.8% vs 4.8% vs. 3.7%, p = 0.60), but definite/probable ST was higher in STEMI patients (1.9% vs 0.5% vs 0.7%, p = 0.03). Adjusted outcomes were not different in MI versus UA patients.

CONCLUSIONS

Despite the novel EPC capture technology, COMBO stent PCI was associated with somewhat greater risk of 1-year TLF in ACS than in non-ACS patients, without significant differences in stent thrombosis. No differences were observed in 1-year TLF among ACS subtypes.

Drug eluting implants in pharmaceutical development and clinical practice

Introduction: Drug eluting implants offer patient convenience and improved compliance through less frequent dosing, eliminating repeated, painful injections and providing localized, site specific delivery with applications in contraception, ophthalmology, and oncology.Areas covered: This review provides an overview of available implant products, design approaches, biodegradable and non-biodegradable polymeric materials, and fabrication techniques with a focus on commercial applications and industrial drug product development. Developing trends in the field, including expanded availability of suitable excipients, development of novel materials, scaled down manufacturing process, and a wider understanding of the implant development process are discussed and point to opportunities for differentiated drug eluting implant products.Expert opinion: In the future, long-acting implants will be important clinical tools for prophylaxis and treatment of global health challenges, especially for infectious diseases, to reduce the cost and difficulty of treating chronic indications, and to prolong local delivery in difficult to administer parts of the body. These products will help improve patient safety, adherence, and comfort.

Phenolic-amine chemistry mediated synergistic modification with polyphenols and thrombin inhibitor for combating the thrombosis and inflammation of cardiovascular stents

Antithrombogenicity, anti-inflammation, and rapid re-endothelialization are central requirements for the long-term success of cardiovascular stents. In this work, a plant-inspired phenolic-amine chemistry strategy was developed to combine the biological functions of a plant polyphenol, tannic acid (TA), and the thrombin inhibitor bivalirudin (BVLD) for tailoring the desired multiple surface functionalities of cardiovascular stents. To realize the synergistic modification of TA and BVLD on a stent surface, an amine-bearing coating of plasma polymerized allylamine was firstly prepared on the stent surface, followed by the sequential conjugation of TA and BVLD in alkaline solution based on phenolic-amine chemistry (i.e., Michael addition reaction). TA and BVLD were successfully immobilized onto the stent surface with considerable amounts of 330 ± 12 and 930 ± 80 ng/cm², respectively. The abundant phenolic hydroxyl groups of TA imparted the stent with ability to suppress inflammation. Meanwhile, BVLD provided an antithrombogenic and endothelial-friendly microenvironment. As a result, the combined functions of the TA and BVLD facilitate the rapid stent re-endothelialization for reduced intimal hyperplasia in vivo, and may be a promising strategy to address the clinical complications associated with restenosis and late stent thrombosis.

One-year clinical outcomes in patients with chronic kidney disease treated with COMBO stents: From the COMBO collaboration

BACKGROUND

Chronic kidney disease (CKD) patients undergoing percutaneous coronary intervention (PCI) experience greater ischemic events including clinically driven target lesion revascularization (CD-TLR). Whether the COMBO biodegradable-polymer sirolimus-eluting stent promotes better outcomes in these patients by virtue of endothelial progenitor cell capture technology is unknown.

OBJECTIVE

We examined one-year outcomes by CKD status from the COMBO collaboration.

METHODS

The COMBO collaboration was a patient-level pooled dataset from the REMEDEE and MASCOT registries (3,614 patients) of all-comers undergoing attempted COMBO stent PCI. The primary endpoint was one-year target lesion failure (TLF), composite of cardiac death, target-vessel myocardial infarction (TV-MI) or CD-TLR. Secondary endpoints included stent thrombosis (ST).

RESULTS

The study included 6.4% (n = 231) CKD and 93.6% (n = 3,361) non-CKD patients. CKD patients were older and included more women with greater prevalence of several comorbidities but similar rate of acute coronary syndrome (50.6% vs. 54.5%, p = .26). CKD patients underwent radial PCI less often (56.1% vs. 70.3%, p < .001) and received clopidogrel (78.6% vs. 68.3%) more often (p = .004). One-year TLF occurred in 7.9% CKD vs. 3.7% non-CKD patients, p = .001. CKD patients also demonstrated greater incidence of cardiac death (6.2% vs. 1.2%, p < .0001), TV-MI (2.7% vs. 1.1%, p = .04) but similar CD-TLR (2.7% vs 2.2%, p = .61) and definite/probable ST (1.4% vs. 0.8%, p = .42), compared to non-CKD patients.

CONCLUSIONS

CKD patients treated with COMBO stents had significantly greater incidence of one-year TLF compared to non-CKD patients driven by cardiac death and to a lesser extent TV-MI but not CD-TLR. They had similar rates of definite/probable ST.

1-Year COMBO stent outcomes stratified by the PARIS bleeding prediction score: From the MASCOT registry

Background

The COMBO stent is a biodegradable-polymer sirolimus-eluting stent with endothelial progenitor cell capture technology for faster endothelialization.

Objective

We analyzed COMBO stent outcomes in relation to bleeding risk using the PARIS bleeding score.

Methods

MASCOT was an international registry of all-comers undergoing attempted COMBO stent implantation. We stratified patients as low bleeding-risk (LBR) for PARIS score ≤ 3 and intermediate-to-high (IHBR) for score > 3 based on baseline age, body mass index, anemia, current smoking, chronic kidney disease and need for triple therapy. Primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, myocardial infarction (MI) not clearly attributed to a non-target vessel or clinically-driven target lesion revascularization (TLR). Bleeding was adjudicated using the Bleeding Academic Research Consortium (BARC) definition. Dual antiplatelet therapy (DAPT) cessation was independently adjudicated.

Results

The study included 56% (n = 1270) LBR and 44% (n = 1009) IHBR patients. Incidence of 1-year TLF was higher in IHBR patients (4.1% vs. 2.6%, p = 0.047) driven by cardiac death (1.7% vs. 0.7%, p = 0.029) with similar rates of MI (1.8% vs. 1.1%, p = 0.17), TLR (1.5% vs. 1.6%, p = 0.89) and definite/ probable stent thrombosis (1.2% vs. 0.6%, p = 0.16). Incidence of 1-year major BARC 3 or 5 bleeding was significantly higher in IHBR patients (2.3% vs. 0.9%, p = 0.0094), as was the incidence of DAPT cessation (29.3% vs. 22.8%, p < 0.01), driven by physician-guided discontinuation.

Conclusions

Patients with intermediate-to-high PARIS bleeding risk in the MASCOT registry experienced greater incidence of 1-year TLF, major bleeding and DAPT cessation than LBR patients, without significant differences in stent thrombosis.

Single and multi-functional coating strategies for enhancing the biocompatibility and tissue integration of blood-contacting medical implants

Device-associated clot formation and poor tissue integration are ongoing problems with permanent and temporary implantable medical devices. These complications lead to increased rates of mortality and morbidity and impose a burden on healthcare systems. In this review, we outline the current approaches for developing single and multi-functional surface coating techniques that aim to circumvent the limitations associated with existing blood-contacting medical devices. We focus on surface coatings that possess dual hemocompatibility and biofunctionality features and discuss their advantages and shortcomings to providing a biocompatible and biodynamic interface between the medical implant and blood. Lastly, we outline the newly developed surface modification techniques that use lubricant-infused coatings and discuss their unique potential and limitations in mitigating medical device-associated complications.

1-Year Outcomes with COMBO Stents in Small-Vessel Coronary Disease: Subgroup Analysis From the COMBO Collaboration

BACKGROUND

Small vessel diameter is associated with higher risk of target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). The COMBO sirolimus-eluting biodegradable-polymer stent has a proprietary anti-CD34 antibody layer to enhance homogeneous endothelialization, which may be advantageous in treating small vessels.

OBJECTIVE

We examined for differences in 1-year clinical outcomes after PCI by maximum implanted stent diameter from the COMBO collaboration.

METHODS

The COMBO collaboration (n = 3614) is a patient-level pooled dataset of patients undergoing PCI with COMBO stents in the MASCOT and REMEDEE multicenter registries. Stent diameter was available in 3590 (99.3%) patients. We compared patients receiving COMBO stents <3 mm versus ≥3 mm. The primary endpoint was 1-year target lesion failure (TLF), composite of cardiac death, target vessel-myocardial infarction (TV-MI) or clinically driven TLR. Secondary outcomes included stent thrombosis (ST). Adjusted outcomes were assessed using Cox regression methods.

RESULTS

The study included 792 (22%) patients with small stents <3 mm and 2798 (78%) patients with large stents ≥3 mm. Small stent patients included more women with lower body mass index and higher prevalence of diabetes but similar prevalence of acute coronary syndrome. Risk of 1-year TLF was similar in small and large stent groups (4.4% vs. 3.8%, HR 1.12, 95% CI 0.74-1.72, p = 0.58). There were no differences in the rates of cardiac death (1.7% vs. 1.5%, p = 0.74), TV-MI (1.4% vs. 1.2%, p = 0.58) or TLR (2.7% vs. 2.1%, p = 0.31). Definite or probable ST occurred in 1.3% of the small stent and 0.7% of the large stent PCI patients, p = 0.14, HR 2.13, 95% CI 0.93-5.00, p = 0.07.

CONCLUSIONS

One-year ischemic outcomes after COMBO PCI were similar irrespective of stent diameter in this all-comers international cohort.

Device profile of the Resolute Onyx Zotarolimus eluting coronary stent system for the treatment of coronary artery disease: overview of its safety and efficacy

Introduction: The increasing complexity of patients undergoing percutaneous coronary intervention (PCI) regarding both coronary anatomy and comorbidities requires dedicated devices. The Resolute Onyx (R-Onyx, Medtronic, CA, USA) stent is a novel durable polymer zotarolimus-eluting stent (ZES) promising better deliverability, increased radiopacity and lower thrombogenicity.Areas covered: In this review, we discuss device features, preclinical evidence, and clinical studies including patients treated with R-Onyx. The BIONYX and Onyx ONE studies were two major landmark trials demonstrating non-inferiority of R-Onyx as compared to other latest generation devices. We also elaborate on alternative innovations in drug-eluting stent (DES) technology and how R-Onyx fits into this field.Expert opinion: R-Onyx is designed to address the challenges of contemporary PCI, but evidence on its clinical performance is largely derived from studies on older generation devices from the ZES family. Nonetheless, all clinical studies on R-Onyx consistently show excellent outcomes, with particularly low rates of stent thrombosis, making it a promising candidate for short dual antiplatelet regimens. In addition, R-Onyx is available with a wide range of stent diameters allowing accurate sizing for both very small and very large coronary vessels.

Capturing Endothelial Cells by Coronary Stents - From Histology to Clinical Outcomes

Introduction of drug-eluting stents (DES) in the therapy of patients with coronary artery disease resulted in the significant reduction of in-stent restenosis compared to bare-metal stent (BMS) treatment. However, the high incidence of late stent thrombosis with DES emerged as one of the safety concerns after their implantation. Enhancing stent endothelization by improved early healing and neointimal strut coverage emerged as possible solution for this late complication. Endothelial progenitor cells (EPC) capturing stents are designed to promote in situ endothelization with immobilized, antihuman, anti-CD34 antibodies attached to the luminal stent surface. Anti-CD34 antibodies target and capture EPC from circulation, which further differentiate into vascular endothelial cells and form functional endothelial layer on the stent surface. These cells are also capable of secreting pro-angiogenic factors that stimulate local endothelial cells to proliferate and migrate. Preclinical and clinical studies proved feasibility, efficacy and safety of EPC capturing stents in stable and high-risk patients with coronary artery disease. Rapid and extensive endothelization of EPC capturing stents translated into favorable profile of clinical outcomes, comparable to efficacy of BMSs and DESs. Therefore, we here present the most important results from the experimental and clinical studies that explored ECP capturing strategy to enhance endothelization, reduce the incidence of instent thrombosis and improve outcomes of patients with coronary artery disease, along with the future perspectives in this promising therapeutic approach.

The REMEDEE trial: 5-Year results on a novel combined sirolimus-eluting and endothelial progenitor cells capturing stent

OBJECTIVES

To evaluate the long-term safety and efficacy of the novel combined sirolimus-eluting endothelial progenitor cell capture Combo stent (OrbusNeich, Fort Lauderdale, FL) at 5 years in the REMEDEE (Randomized study to Evaluate the safety and effectiveness of an abluMinal sirolimus coated bio-Engineered stEnt) trial.

BACKGROUND

Drug-eluting stents have limited restenosis and reintervention but are complicated by late and very late thrombosis and accelerated neoatherosclerosis. Alternative or adjunctive technologies are needed to address these limitations.

METHODS

A total of 183 patients with de novo lesions in native coronary arteries were randomized 2:1 to Combo (n = 124) or Taxus Liberté (n = 59). Primary endpoint was 9 month angiographic in-stent late lumen loss and the secondary endpoint was the occurrence of major adverse events (MACE) through 5-year follow-up.

RESULTS

Compared with Taxus, after 5 years the Combo stent was associated with similar rates of MACE (18.3% vs. 16.9%, p = .89), cardiac death (0.8% vs. 5.1%, p = .07), myocardial infarction (4.1% vs. 3.4%, p = .81), target lesion (9.4% vs. 10.2%, p = .78), and target vessel revascularization (14.4% vs. 11.9%, p = .73). No cases of definite stent thrombosis were reported in the Combo group. The follow-up rate at 5 years was 97.7%.

CONCLUSION

At 5-year follow-up, the Combo stent remained clinically safe and effective with an overall low rate of MACE comparable to Taxus.

Automated stent coverage analysis in intravascular OCT (IVOCT) image volumes using a support vector machine and mesh growing

Absence of vascular-stent tissue coverage by IVOCT is a biomarker for potential stent-related thrombosis. We developed highly-automated algorithms to classify covered and uncovered struts and quantitatively evaluate stent apposition. We trained a machine learning model on 7,125 images, and included an active learning, relabeling step to improve noisy labels. We obtained uncovered strut classification sensitivity/specificity (94%/90%) comparable to analyst inter-and-intra-observer variability and AUC (0.97), and tissue coverage thickness measurement arguably better than the commercial product. By comparing classification models from regular and relabeled data sets, we observed robustness of the support vector machine to noisy data. A graph-based algorithm detected clusters of uncovered struts thought to pose a greater risk than isolated uncovered struts. The software enables highly-automated, objective, repeatable, comprehensive stent analysis.

Comparisons of early vascular reactions in biodegradable and durable polymer-based drug-eluting stents in the porcine coronary artery

Current drug-eluting stents have abluminal polymer coating; however, thrombus formation in these compared with that in uniformly coated stents remains controversial. We evaluated thrombus formation and early endothelialization after using abluminal biodegradable polymer-coated sirolimus- (BP-SES), and everolimus-eluting stents (BP-EES) versus a durable polymer-coated everolimus-eluting stent (DP-EES) in an in vivo setting. BP-SES, BP-EES, and DP-EES (n = 6 each) were implanted in coronary arteries of 12 mini-pigs that were then sacrificed after 7 and 10 days. Stents were stained with hematoxylin and eosin, and a combined Verhoeff and Masson trichrome stain. Areas of fibrin deposition were digitally detected and measured with off-line morphometric software. Stents were investigated for re-endothelialization by transmission electron microscopy. At 7 days, histological analysis revealed the lowest area of fibrin deposition in BP-SES (BP-SES vs. BP-EES vs. DP-EES; 0.10 ± 0.06 mm2 vs. 0.15 ± 0.07 mm2 vs. 0.19 ± 0.06 mm2, p = 0.0004). At 10 days, the area of fibrin deposition was significantly greater in DP-EES (0.13 ± 0.04 mm2 vs. 0.14 ± 0.05 mm2 vs. 0.19 ± 0.08 mm2, p = 0.007). Endothelial cells in BP-SES demonstrated a significantly greater number of tight junctions than those in DP-EES according to by transmission electron microscopy for both days (p<0.05). Various parameters, including an inflammatory reaction and neointimal formation, were comparable among the groups at 7 and 10 days. An abluminal biodegradable polymer-coated SES showed the least fibrin deposition and greatest endothelial cell recovery at an early stage following implantation in the coronary arteries of mini-pigs.

Clinical Outcomes One Year and Beyond After Combination Sirolimus-Eluting Endothelial Progenitor Cell Capture Stenting During Primary Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction

BACKGROUND/PURPOSE

Primary percutaneous coronary intervention (PCI) during acute ST-segment elevation myocardial infarction (STEMI) represents a thrombotic milieu and is associated with delayed healing after stenting. The pro-healing combination sirolimus eluting endothelial progenitor cell (EPC) capture stents encourage early endothelialization after stenting and may be beneficial in the STEMI population. We aim to evaluate the clinical outcomes one year and beyond for patients with STEMI who received the combination sirolimus eluting EPC capture stents during primary PCI.

METHODS/MATERIAL

All STEMI patients implanted with combination sirolimus eluting EPC capture stents during primary PCI from November 2013 to December 2016 were enrolled. The primary outcome was target lesion failure (TLF) at in-hospital, one-month, one-year and beyond one year.

RESULTS

A total of 260 consecutive STEMI patients (283 lesions) were implanted with 313 combination sirolimus eluting EPC capture stents during primary PCI. Mean age was 56.1 ± 11.2 years and 88.8% were male. One in ten patients (10.9%) had cardiogenic shock on presentation, 7.3% needed mechanical ventilation and 7.7% had intra-aortic balloon pump inserted. A total of 97.9% of lesions achieve final TIMI 3 flow. Device success was seen in all patients. At extended follow up period (median 23.4 months), the clinical outcomes were TLF 8.8%, major adverse cardiovascular events 10.8%, cardiac mortality 4.2%, target vessel myocardial infarction 3.4%, target lesion revascularization 3.8%, and definite stent thrombosis 1.9%.

CONCLUSIONS

This study demonstrated acceptable clinical outcomes for an all-comers STEMI patients undergoing primary PCI with the use of combination sirolimus eluting EPC cell capture stents.

The dual-therapy COMBO stent: a rationale for a light dual antiplatelet therapy treatment

The COMBO stent is a new, sirolimus-eluting bioresorbable polymer, bioengineered stent. This technology combines the advantages of second-generation drug-eluting stents with the endothelial progenitor cell capture technology mediated by the anti-CD34 antibody coating on the COMBO luminal surface. This dual technology should improve vessel endothelium regeneration and may lay the biological basis for a short dual antiplatelet therapy course. As new evidence is adding on the safety and efficacy of this stent compared with first- and second-generation drug-eluting stents and across a variety of patient populations, aim of this review is to summarize available clinical experience and future perspective with this device.

The effects of stenting on coronary endothelium from a molecular biological view: Time for improvement?

Coronary artery stenting following balloon angioplasty represents the gold standard in revascularization of coronary artery stenoses. However, stent deployment as well as percutaneous transluminal coronary angioplasty (PTCA) alone causes severe injury of vascular endothelium. The damaged endothelium is intrinsically repaired by locally derived endothelial cells and by circulating endothelial progenitor cells from the blood, leading to re‐population of the denuded regions within several weeks to months. However, the process of re‐endothelialization is often incomplete or dysfunctional, promoting in‐stent thrombosis and restenosis. The molecular and biomechanical mechanisms that influence the process of re‐endothelialization in stented segments are incompletely understood. Once the endothelium is restored, endothelial function might still be impaired. Several strategies have been followed to improve endothelial function after coronary stenting. In this review, the effects of stenting on coronary endothelium are outlined and current and future strategies to improve endothelial function after stent deployment are discussed.

Randomized clinical comparison of the dual-therapy CD34 antibody-covered sirolimus-eluting Combo stent with the sirolimus-eluting Orsiro stent in patients treated with percutaneous coronary intervention: Rationale and study design of the Scandinavian Organization for Randomized Trials with Clinical Outcome (SORT OUT) X trial

BACKGROUND

The Combo stent (OrbusNeich, Hoevelaken, the Netherlands) combining an abluminal, bioabsorbable polymer eluting sirolimus with a luminal CD34+ antibody to capture endothelial progenitor cells has been developed to further improve safety and efficacy of coronary interventions. We have designed a large-scale registry-based randomized clinical trial to compare the Combo stent to the Orsiro stent (Biotronik, Bülach, Switzerland) in patients undergoing percutaneous coronary intervention.

METHODS

The SORT OUT X study will randomly assign 3,140 patients to treatment with Combo or Orsiro stents at 3 sites in Western Denmark. Patients are eligible if they are ≥18 years old, have chronic stable coronary artery disease or acute coronary syndromes, and have ≥1 coronary lesion with >50% diameter stenosis requiring treatment with a drug-eluting stent. The primary end point target lesion failure is a composite of cardiac death, myocardial infarction (not related to other than index lesion), or target lesion revascularization within 12 months. Clinically driven event detection will be derived from validated Danish registries. An event rate of 4.2% is assumed in each stent group. With a sample size of 1,570 patients in each treatment arm, a 2-group large-sample normal approximation test of proportions with a 1-sided 5% significance level will have 90% power to detect noninferiority of the Combo stent compared with the Orsiro stent with a predetermined noninferiority margin of 2.1%.

CONCLUSION

The SORT OUT X trial will determine whether the dual-therapy Combo stent is noninferior to the Orsiro stent with respect to clinically driven events (ClinicalTrials.govNCT03216733).

Adiponectin as a potential therapeutic target for the treatment of restenosis

Restenosis is a pathologic re-narrowing of a coronary artery lesion after mechanical injury. Its pathophysiological mechanisms have not been fully elucidated at present, but are thought to include inflammation, vascular smooth muscle cell (VSMC) proliferation, and matrix remodeling, beginning with insufficient endothelium healing. Restenosis presents with angina symptoms or acute coronary syndromes and lead to a revascularization, either with coronary artery bypass or repeat percutaneous coronary intervention. Some studies have reported that hypoadiponectinemia has been an independent risk factor for the onset of acute coronary syndromes and restenosis. Accumulating evidence shows that low concentrations of adiponectin may be involved in impairing endothelium functions, inflammation, and VSMC proliferation that lead to restenosis. Preclinical studies have proven that adiponectin promotes endothelium healing, effectively inhibits inflammation, and maintains contractile phenotypes of VSMCs, indicating that it may be developed as a new therapeutic target for the treatment of restenosis.

Histopathological comparison of biodegradable polymer and permanent polymer based sirolimus eluting stents in a porcine model of coronary stent implantation

Biodegradable stent coatings were recently introduced as a potential solution to overcome sustained inflammatory responses observed with permanent polymer-based drug-eluting stents. In a preliminary study, selected biodegradable or permanent polymer-based sirolimus-eluting stent (SES) formulations were screened for effectiveness in comparison to bare metal stents (BMS) at 28 days. Subsequently, the most favourable SES formulation was compared to commercially available SES (CypherTM) at 28,90 and 180 days to investigate the histopathologic response as well as tissue, blood and organ pharmacokinetics. Overlapping SES implantation was conducted to evaluate vascular healing at 28 days in this particular setting. SES with biodegradable poly (L-lactide) polymer (PLLA) or poly(lactide-co-glycolide) showed the most favourable outcome with regards to reductions in neointimal area in comparison to BMS at 28 days. The PLLA SES showed a similar reduction in neointimal area compared to CypherTM at 28 days, with significant greater reductions at 90 and 180 days (1.7 ± 0.7 mm2 vs. 3.1 ± 1.5 mm2, p=0.03 and 1.8 ± 1.2 mm2 vs. 3.0 ± 1.5 mm2, p=0.01, respectively). Sirolimus vascular tissue concentrations were detectable up to 90 days following implantation. Overlapping stented segments showed favourable histopathologic results with respect to fibrin deposition and endothelialisation at 28 days. In conclusion, the use of PLLA as drugeluting matrix resulted in mild inflammatory responses in the presence of effective sirolimus tissue concentrations. The greater efficacy observed at long-term follow-up in PLLA SES compared to CypherTM may be a multifactorial result of stent design, polymer biocompatibility and improved release kinetics.

In vivo delivery and long-term tissue retention of nano-encapsulated sirolimus using a novel porous balloon angioplasty system

AIMS

Among antirestenotic compounds, sirolimus displays a superior safety profile compared to paclitaxel, but its pharmacokinetic properties make it a challenging therapeutic candidate for single-time delivery. Herein we evaluate the feasibility of delivery, long-term retention and vascular effects of sirolimus nanoparticles delivered through a novel porous angioplasty balloon in normal porcine arteries and in a swine model of in-stent restenosis (ISR).

METHODS AND RESULTS

Sirolimus nanoparticle formulation was delivered via porous balloon angioplasty to 753 coronary artery segments for pharmacokinetic studies and 26 segments for biological effect of sirolimus delivery in different clinical scenarios (de novo [n=8], ISR [n=6] and following stent implantation [n=12]). Sirolimus coronary artery concentrations were above the target therapeutic level of 1 ng/mg after 26 days, and were >100-fold higher in coronary artery treatment sites than in distal myocardium and remote tissues at all time points. At 28 days, reduction in percent stenosis in formulation-treated sites compared to balloon angioplasty treatment was noted in all three clinical scenarios, with the largest effect seen in the de novo study.

CONCLUSIONS

Local coronary delivery of sirolimus nanoparticles in the porcine model using a novel porous balloon delivery system achieved therapeutic long-term intra-arterial drug levels without significant systemic residual exposure.

Progenitor Cells for Arterial Repair: Incremental Advancements towards Therapeutic Reality

Coronary revascularization remains the standard treatment for obstructive coronary artery disease and can be accomplished by either percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery. Considerable advances have rendered PCI the most common form of revascularization and improved clinical outcomes. However, numerous challenges to modern PCI remain, namely, in-stent restenosis and stent thrombosis, underscoring the importance of understanding the vessel wall response to injury to identify targets for intervention. Among recent promising discoveries, endothelial progenitor cells (EPCs) have garnered considerable interest given an increasing appreciation of their role in vascular homeostasis and their ability to promote vascular repair after stent placement. Circulating EPC numbers have been inversely correlated with cardiovascular risk, while administration of EPCs in humans has demonstrated improved clinical outcomes. Despite these encouraging results, however, advancing EPCs as a therapeutic modality has been hampered by a fundamental roadblock: what constitutes an EPC? We review current definitions and sources of EPCs as well as the proposed mechanisms of EPC-mediated vascular repair. Additionally, we discuss the current state of EPCs as therapeutic agents, focusing on endogenous augmentation and transplantation.