Randomized trial of paclitaxel- versus sirolimus-eluting stents for treatment of coronary restenosis in sirolimus-eluting stents: the ISAR-DESIRE 2 (Intracoronary Stenting and Angiographic Results: Drug Eluting Stents for In-Stent Restenosis 2) study

Long-term outcomes of DCB and DES for the treatment of in-stent restenosis in relation to the vessel size

BACKGROUND

Percutaneous coronary intervention (PCI) with drug-coated balloons (DCB) or drug-eluting stents (DES) are well-established treatments for in-stent restenosis, however little is known about the impact of vessel size on the outcomes. The study aimed to evaluate the efficacy and safety profile of DCB versus DES in DES in-stent restenosis depending on the vessel size.

METHODS

Consecutive patients with DES in-stent restenosis who underwent PCI between January 2010 and February 2018 entered the registry with a long-term follow-up. Patients who received DCB at the index procedure were compared with those who received DES in three subgroups depending on the vessel size (≤2.5 mm; 2.5-3.5 mm; >3.5 mm). Data were analyzed using propensity score matching and Kaplan-Meier estimator plots.

RESULTS

Among 1,374 patients with DES in-stent restenosis, 615 were treated with DES and 759 with DCB. After propensity score matching, we analyzed 752 patients in the DES and DCB groups at a long-term follow-up. The risk of DOCE did not differ significantly between the DES and DCB groups, both in the overall population (HR 0.85; 95%CI [0.58; 1.26], log-rank p = 0.41) and when divided into small (HR 0.84; 95%CI [0.36; 1.95], log-rank p = 0.70), medium-sized (HR 0.90; 95%CI [0.49; 1.65], log-rank p = 0.73), and large-sized (HR 0.81; 95%CI [0.42; 1.53], log-rank p = 0.50) coronary arteries. The incidence of all-cause death was significantly higher in the overall DES population (HR 4.03; 95%CI [2.40; 6.79], log-rank p < 0.001) and subgroup of small (HR 5.54; 95%CI [1.80; 17.02], log-rank p = 0.003), medium-sized (HR 4.37; 95%CI [1.92; 9.94], log-rank p = 0.009) and large-sized coronary arteries (HR 3.26; 95%CI [1.35; 7.86], log-rank p = 0.02).

CONCLUSIONS

DES and DCB strategies are comparable methods of treating ISR regardless of the diameter of the treated vessel in a long-term follow-up.

Current Management of In-Stent Restenosis

In-stent restenosis (ISR) remains the primary cause of target lesion failure following percutaneous coronary intervention (PCI), resulting in 10-year incidences of target lesion revascularization at a rate of approximately 20%. The treatment of ISR is challenging due to its inherent propensity for recurrence and varying susceptibility to available strategies, influenced by a complex interplay between clinical and lesion-specific conditions. Given the multiple mechanisms contributing to the development of ISR, proper identification of the underlying substrate, especially by using intravascular imaging, becomes pivotal as it can indicate distinct therapeutic requirements. Among standalone treatments, drug-coated balloon (DCB) angioplasty and drug-eluting stent (DES) implantation have been the most effective. The main advantage of a DCB-based approach is the avoidance of an additional metallic layer, which may otherwise enhance neointimal hyperplasia, provide the substratum for developing neoatherosclerosis, and expose the patient to a persistently higher risk of coronary ischemic events. On the other hand, target vessel scaffolding by DES implantation confers relevant mechanical advantages over DCB angioplasty, generally resulting in larger luminal gain, while drug elution from the stent surface ensures the inhibition of neointimal hyperplasia. Nevertheless, repeat stenting with DES also implies an additional permanent metallic layer that may reiterate and promote the mechanisms leading to ISR. Against this background, the selection of either DCB or DES on a patient- and lesion-specific basis as well as the implementation of adjuvant treatments, including cutting/scoring balloons, intravascular lithotripsy, and rotational atherectomy, hold the potential to improve the effectiveness of ISR treatment over time. In this review, we comprehensively assessed the available evidence from randomized trials to define contemporary interventional treatment of ISR and provide insights for future directions.

Comparative efficacy of interventional therapies and devices for coronary in-stent restenosis: A systematic review and network meta-analysis of randomized controlled trials

Background

In-stent restenosis (ISR) has become a significant obstacle to interventional therapy for atherosclerotic cardiovascular disease. The optimal percutaneous coronary intervention (PCI) strategy for patients with coronary ISR remains controversial. This network meta-analysis (NMA) was aimed to compare and estimate the effectiveness of different PCI strategies and commercial devices for the treatment of patients with coronary ISR.

Methods

In present study, we systematically searched PubMed, Embase, Web of Science, and Cochrane Library from database inception to October 20, 2022, to identify randomized controlled trials. We included studies comparing various PCI strategies for the treatment of any type of coronary ISR. The study was registered with PROSPERO, CRD 42022364308.

Results

We included 44 eligible trials including 8479 patients, 39 trials comparing the treatment effects of 10 PCIs, and 5 trials comparing the efficacy between different types of drug-eluting stent (DES) or drug-coated balloon (DCB) devices. Among the PCIs, everolimus-eluting stent was the optimal strategy considering target lesion revascularization (TLR), percent diameter stenosis (%DS), and binary restenosis (BR), and sirolimus-coated balloon was the optimal strategy considering late lumen loss (LLL). In the comparison of commercial devices, the combination strategy excimer laser coronary angioplasty plus SeQuent Please paclitaxel-coated balloon showed promising therapeutic prospects.

Conclusions

DCB and DES remain the preferred treatment strategies for coronary ISR, considering both the primary clinical outcome (TLR) and the angiographic outcomes (LLL, BR, %DS). Personalized combination interventions including DCB or DES hold promise as a novel potential treatment pattern for coronary ISR.

In-Stent Restenosis Overview: From Intravascular Imaging to Optimal Percutaneous Coronary Intervention Management

Despite ongoing progress in stent technology and deployment techniques, in-stent restenosis (ISR) still remains a major issue following percutaneous coronary intervention (PCI) and accounts for 10.6% of all interventions in the United States. With the continuous rise in ISR risk factors such as obesity and diabetes, along with an increase in the treatment of complex lesions with high-risk percutaneous coronary intervention (CHIP), a substantial growth in ISR burden is expected. This review aims to provide insight into the mechanisms, classification, and management of ISR, with a focus on exploring innovative approaches to tackle this complication comprehensively, along with a special section addressing the approach to complex calcified lesions.

SCAI Expert Consensus Statement on Management of In-Stent Restenosis and Stent Thrombosis

Stent failure remains the major drawback to the use of coronary stents as a revascularization strategy. Recent advances in imaging have substantially improved our understanding of the mechanisms underlying these occurrences, which have in common numerous clinical risk factors and mechanical elements at the time of stent implantation. In-stent restenosis remains a common clinical problem despite numerous improvements in-stent design and polymer coatings over the past 2 decades. It generates significant health care cost and is associated with an increased risk of death and rehospitalization. Stent thrombosis causes abrupt closure of the stented artery and therefore carries a high risk of myocardial infarction and death. This Society for Cardiovascular Angiography & Interventions (SCAI) Expert Consensus Statement suggests updated practical algorithmic approaches to in-stent restenosis and stent thrombosis. A pragmatic outline of assessment and management of patients presenting with stent failure is presented. A new SCAI classification that is time-sensitive with mechanistic implications of in-stent restenosis is proposed. Emphasis is placed on frequent use of intracoronary imaging and assessment of timing to determine the precise etiology because that information is crucial to guide selection of the best treatment option. SCAI recommends image-guided coronary stenting at the time of initial implantation to minimize the occurrence of stent failure. When in-stent restenosis and stent thrombosis are encountered, imaging should be strongly considered to optimize the subsequent approach.

Derivation and validation of the ISAR score to predict the risk of repeat percutaneous coronary intervention for recurrent drug-eluting stent restenosis

BACKGROUND

The treatment of drug-eluting stent (DES) in-stent restenosis (ISR) is challenging as it has a high risk of recurrence.

AIMS

The aim of this analysis was to develop and validate a model to predict the risk of repeat percutaneous coronary intervention (PCI) for recurrent DES-ISR.

METHODS

A retrospective, observational analysis was performed including consecutive patients treated with PCI for DES-ISR at two centres in Germany. Included patients were randomly divided into training and validation cohorts. Two regression analyses identified factors associated with repeat PCI for recurrent DES-ISR up to 1 year. The discriminative ability of the resultant model was then compared to a benchmark ISR classification model using bootstrap resampling. A classification and regression tree analysis and a numerical scoring system (the ISAR score) were used to predict the risk of repeat PCI for recurrent DES-ISR based on the identified predictors.

RESULTS

We included 1,986 patients in the current analysis, divided randomly into training (1,471 patients, 1,778 lesions) and validation (515 patients, 614 lesions) cohorts. Four factor variables (a non-focal ISR pattern, a time interval to ISR of <6 months, ISR of the left circumflex artery and ISR in a calcified vessel) were associated with repeat PCI for recurrent DES-ISR at 1-year follow-up. On bootstrap resampling analysis, the C-statistic for the model including these four variables was 0.60 (95% confidence interval [CI]: 0.57-0.63), whereas the C-statistic for the benchmark ISR classification model was 0.54 (95% CI: 0.52-0.57), a difference that was statistically significant (delta C-statistic 0.062; 95% CI: 0.035-0.094; p<0.001). The cumulative incidence of repeat PCI for recurrent DES-ISR was over three times higher in DES-ISR lesions with an ISAR score of ≥3 in comparison to lesions with an ISAR score of 0.

CONCLUSIONS

This study developed and validated a risk prediction model for repeat PCI for recurrent DES-ISR at 1-year follow-up. This model served to generate the ISAR score, a standardised tool that can be used to predict the 1-year risk of repeat PCI for recurrent DES-ISR.

Management of failed stenting of the unprotected left main coronary artery

Percutaneous coronary intervention (PCI) is increasingly accepted as treatment for unprotected left main coronary artery (ULMCA) disease especially in those patients who are unsuitable for cardiac surgery. Treatment of any stent failure is associated with increased complexity and worse clinical outcomes when compared with de novo lesion revascularization. Intracoronary imaging has provided new insight into mechanisms of stent failure and treatment options have developed considerably over the last decade. There is paucity of evidence on the management strategy for stent failure in the specific setting of ULMCA. Treating any left main with PCI requires careful consideration and consequently treatment of failed stents in ULMCA is complex and provides unique challenges. Consequently, we provide an overview of ULMCA stent failure, proposing a tailored algorithm to guide best management and decision in daily clinical practice, with a special focus on intracoronary imaging characterization of causal mechanisms and specific technical and procedural considerations.

Intravascular Imaging for Guiding In-Stent Restenosis and Stent Thrombosis Therapy

Advances in stent technology and the design of endovascular devices with thinner struts, anti-inflammatory and antithrombotic polymers, and better drug kinetics have enhanced the safety and efficacy of the second-generation drug-eluting stents and broadened their use in the therapy of high-risk patients and complex anatomies. However, despite these developments, in-stent restenosis and stent thrombosis remain the Achilles' heel of percutaneous coronary intervention, with their cumulative incidence reaching up to 10% at 5 years following percutaneous coronary intervention. The treatment of stent failure poses challenges and is associated with a worse prognosis than conventional percutaneous coronary intervention. Several studies have recently highlighted the value of intravascular imaging in identifying causes of stent failure, underscored its role in treatment planning, and registries have shown that its use may be associated with better clinical outcomes. The present review aims to summarize the evidence in the field; it discusses the value of intravascular imaging in identifying the mechanisms of in-stent restenosis and stent thrombosis in assessing the morphological characteristics of neointima tissue that appears to determine long-term outcomes in evaluating procedural results, and presents the findings of studies supporting its value in guiding therapy in stent failure.

Coronary Stenting: Reflections on a 35-Year Journey

Stenting was introduced as a therapy for coronary artery disease 35 years ago, and is currently the most commonly performed minimally invasive procedure globally. Percutaneous coronary revascularization, initially with plain old balloon angioplasty and later with stenting, has dramatically affected the outcomes of acute myocardial infarction and acute coronary syndromes. Coronary stenting is probably the most intensively studied therapy in medicine on the basis of the number of randomized clinical trials for a broad range of indications. Continuous improvements in stent materials, design, and coatings concurrent with procedural innovations have truly been awe-inspiring. The story of stenting is replete with high points and some low points, such as the initial experience with stent thrombosis and restenosis, and the more recent disappointment with bioabsorbable scaffolds. History has shown rapid growth of stent use with expansion of indications followed by contraction of some uses in response to clinical trial evidence in support of bypass surgery or medical therapy. In this review we trace the constantly evolving story of the coronary stent from the earliest experience until the present time. Undoubtedly, future iterations of stent design and materials will continue to move the stent story forward.

Coronary In-Stent Restenosis: JACC State-of-the-Art Review

The introduction and subsequent iterations of drug-eluting stent technologies have substantially improved the efficacy and safety of percutaneous coronary interventions. However, the incidence of in-stent restenosis (ISR) and the resultant need for repeated revascularization still occur at a rate of 1%-2% per year. Given that millions of drug-eluting stents are implanted each year around the globe, ISR can be considered as a pathologic entity of public health significance. The mechanisms of ISR are multifactorial. Since the first description of the angiographic patterns of ISR, the advent of intracoronary imaging has further elucidated the mechanisms and patterns of ISR. The armamentarium and treatment strategies of ISR have also evolved over time. Currently, an individualized approach using intracoronary imaging to characterize the underlying substrate of ISR is recommended. In this paper, we comprehensively reviewed the incidence, mechanisms, and imaging characterization of ISR and propose a contemporary treatment algorithm.

Glycaemic Control in Patients Undergoing Percutaneous Coronary Intervention: What Is the Role for the Novel Antidiabetic Agents? A Comprehensive Review of Basic Science and Clinical Data

Coronary artery disease (CAD) remains one of the most important causes of morbidity and mortality worldwide, and revascularization through percutaneous coronary interventions (PCI) significantly improves survival. In this setting, poor glycaemic control, regardless of diabetes, has been associated with increased incidence of peri-procedural and long-term complications and worse prognosis. Novel antidiabetic agents have represented a paradigm shift in managing patients with diabetes and cardiovascular diseases. However, limited data are reported so far in patients undergoing coronary stenting. This review intends to provide an overview of the biological mechanisms underlying hyperglycaemia-induced vascular damage and the contrasting actions of new antidiabetic drugs. We summarize existing evidence on the effects of these drugs in the setting of PCI, addressing pre-clinical and clinical studies and drug-drug interactions with antiplatelet agents, thus highlighting new opportunities for optimal long-term management of these patients.

Management of in-stent restenosis

In-stent restenosis (ISR) remains the most common cause of stent failure after percutaneous coronary intervention (PCI). Recent data suggest that ISR-PCI accounts for 5-10% of all PCI procedures performed in current clinical practice. This State-of-the-Art review will primarily focus on the management of ISR but will begin by briefly discussing diagnosis and classification. We then move on to detail the evidence base underpinning the various therapeutic strategies for ISR before finishing with a proposed ISR management algorithm based on current scientific data.

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

The impact of J-CTO score on in-stent chronic total occlusion percutaneous coronary intervention

AIM

The purpose of this study was to investigate the impact of J-CTO (Multicenter Chronic Total Occlusion Registry of Japan) score on in-stent chronic total occlusion (IS-CTO) percutaneous coronary intervention (PCI).

METHODS

A retrospective data collection was conducted on 474 patients undergoing a difficult IS-CTO PCI from January 2015 to December 2018. The primary endpoint (major adverse cardiovascular events [MACE]) consisted of target-vessel myocardial infarction (MI), cardiac death or ischemia-driven target-vessel revascularisation (TVR) at follow-up. The cut-off points were estimated by the Youden index.

RESULTS

The overall procedural success rate was 77.6%. On multivariable analysis, factors including proximal bending (beta coefficient [β] = 3.465), tortuosity (β = 3.064), stent under expansion (β = 3.109) and poor distal landing zone (β = 1.959) were associated with technical failure via antegrade approach but not the J-CTO score (OR = 0.632; 95% CI [0.352-1.134]; P = .124). After a median follow-up of 30 months (interquartile range: 17-42 months), multivariable analysis revealed that receiving >18 months of dual antiplatelet therapy (DAPT) was an independent predictor of decreased risk of MACE (HR: 2.690; 95% CI: 1.346-5.347; P = .005). But the J-CTO score was not an independent predictor of MACE (HR: 1.018; 95% CI: 0.728-1.424; P = .917).

CONCLUSIONS

J-CTO score system is not a helpful tool to predict the technical success of difficult IS-CTO PCI via antegrade approach, nor does it correlate with long-term outcomes in patients undergoing IS-CTO PCI. Nevertheless, factors associated with technical failure include proximal bending of ≥30 degrees, under expansion of ≥10 mm, moderate or severe tortuosity (bending) ≥20 and poor distal target. Long-term DAPT therapy contributes significantly to decreased MACE.

Influences of Stent Design on In-Stent Restenosis and Major Cardiac Outcomes: A Scoping Review and Meta-Analysis

Thanks to the developments in implantable biomaterial technologies, invasive operating procedures, and widespread applications especially in vascular disease treatment, a milestone for interventional surgery was achieved with the introduction of vascular stents. Despite vascular stents providing a solution for embolisms, this technology includes various challenges, such as mechanical, electro-chemical complications, or in-stent restenosis (ISR) risks with long-term usage. Therefore, further development of biomaterial technologies is vital to overcome such risks and problems. For this purpose, recent research has focused mainly on the applications of surface modification techniques on biomaterials and vascular stents to increase their hemocompatibility. ISR risk has been reduced with the development and prevalent usage of the art technology stent designs of drug-eluting and biodegradable stents. Nevertheless, their problems have not been overcome completely. Furthermore, patients using drug-eluting stents are faced with further clinical challenges. Therefore, the bare metal stent, which is the first form of the vascular stent technology and includes the highest ISR risk, is still in common usage for vascular treatment applications. For this reason, further research is necessary to solve the remaining vital problems. In this scoping review, stent-based major cardiac events including ISR are analyzed depending on different designs and material selection in stent manufacturing. Recent and novel approaches to overcome such challenges are stated in detail.

Results of paclitaxel-drug-coated balloons (Pantera Lux) for coronary in-stent restenosis: Italian experience from REGistry of Paclitaxel Eluting Balloon in ISR study

AIMS

Drug-eluting stent (DES) implantation is an effective treatment of in-stent restenosis (ISR). However, literature data indicate that drug-coated balloons (DCBs) may be a valid alternative, particularly for recurrent ISR. We sought to evaluate clinical results on the long-term efficacy of a new DCB for ISR treatment.

METHODS

One hundred and ninety-nine patients were treated with paclitaxel drug-coated balloons (Pantera Lux, Biotronik, Switzerland) in the Italian REGistry of Paclitaxel Eluting Balloon in ISR (REGPEB study). Clinical follow-up was scheduled at 1 and 12 months. A subgroup of patients received adjunctive 5-year follow-up. Primary end point was Major Adverse Cardiac Events (MACE) at 1 year.

RESULTS

A total of 214 ISR coronary lesions were treated (75.4% DES-ISR). Mean time between stent implantation and DCB treatment is 41 months. DCBs were successfully delivered in 99% of the cases; crossover to a DES occurred in 3% of cases. Procedural success rate was 98.5%. Clinical success rate was 98.5%. First-month follow-up compliance was 98% and freedom from MACE was 96.9%. Twelve-month follow-up compliance was 89.3% with a freedom from MACE rate of 87.3% (CI: 81.3-91.5%). Five-year long-term follow-up showed 65.2% of freedom from MACE.

CONCLUSION

Our study confirms that Pantera Lux treatment is effective and well tolerated in ISR, showing good acute and long/very long-term results in the treatment of complex lesions (DES and late ISR).

The Use of Bioactive Polymers for Intervention and Tissue Engineering: The New Frontier for Cardiovascular Therapy

Coronary heart disease remains one of the leading causes of death in most countries. Healthcare improvements have seen a shift in the presentation of disease with a reducing number of ST-segment elevation myocardial infarctions (STEMIs), largely due to earlier reperfusion strategies such as percutaneous coronary intervention (PCI). Stents have revolutionized the care of these patients, but the long-term effects of these devices have been brought to the fore. The conceptual and technologic evolution of these devices from bare-metal stents led to the creation and wide application of drug-eluting stents; further research introduced the idea of polymer-based resorbable stents. We look at the evolution of stents and the multiple advantages and disadvantages offered by each of the different polymers used to make stents in order to identify what the stent of the future may consist of whilst highlighting properties that are beneficial to the patient alongside the role of the surgeon, the cardiologist, engineers, chemists, and biophysicists in creating the ideal stent.

Long-term outcomes of percutaneous coronary intervention for in-stent chronic total occlusion

BACKGROUND

The development of the technique has improved the success rate of percutaneous coronary intervention (PCI) for in-stent chronic total occlusion (IS-CTO). However, long-term outcomes remain unclear. The present study sought to investigate long-term outcomes of PCI for IS-CTO.

METHODS

A total of 474 IS-CTO patients were enrolled at two cardiac centers from 2015 to 2018 retrospectively. These patients were allocated into either successful or failed IS-CTO PCI groups. The primary endpoint (major adverse cardiac events [MACE]) consisted of recurrent angina pectoris (RAP), target-vessel myocardial infarction (MI), heart failure, cardiac death, or ischemia-driven target-vessel revascularization (TVR) at follow-up. Multivariable Cox regression analysis was used to investigate the association between treatment appropriateness and clinical outcomes.

RESULTS

A total of 367 patients were successfully treated with IS-CTO PCI while 107 patients had failed recanalization. After a median follow-up of 30 months (interquartile range: 17-42 months), no significant difference was observed between the two groups for the following parameters: cardiac death (successful PCI vs. failed PCI: 0.9% vs. 2.7%; adjusted hazard ratio [HR]: 1.442; 95% confidence interval [CI]: 0.21-9.887; P = 0.709), RAP (successful PCI vs. failed PCI: 40.8% vs. 40.0%; adjusted HR: 1.025; 95% CI: 0.683-1.538; P = 0.905), heart failure (successful PCI vs. failed PCI: 6.1% vs. 2.7%; adjusted HR: 0.281; 95% CI: 0.065-1.206; P = 0.088), target-vessel related MI (successful PCI vs. failed PCI: 1.5% vs. 2.7%; adjusted HR: 1.150; 95% CI: 0.221-5.995; P = 0.868), MACE (successful PCI vs. failed PCI: 44.2% vs. 45.3%; adjusted HR: 1.052; 95% CI: 0.717-1.543; P = 0.797). More patients were free of angina in the successful IS-CTO PCI group compared with failed PCI in the first (80.4% vs. 60%, P < 0.01) and second years (73.3% vs. 60.0%, P = 0.02) following up. Successful IS-CTO PCI had a lower incidence of MACE in the first and second years (20.2% vs. 40.0%, P < 0.01; 27.9% vs. 41.3%, P = 0.023) compared with failed PCI. After a median follow-up of 30 months, the reocclusion rate was 28.5% and TVR was 26.1% in the successful IS-CTO PCI group. Receiving >18 months of dual antiplatelet therapy (DAPT) was an independent predictor of decreased risk of TVR (HR: 2.682; 95% CI: 1.295-5.578; P = 0.008) or MACE (without TVR) (HR: 1.898; 95% CI: 1.036-3.479; P = 0.038) in successful IS-CTO PCI.

CONCLUSIONS

After a median follow-up of 30 months, the successful IS-CTO PCI group had MACE similar to that of the failed PCI group. However, the successful IS-CTO PCI group had improved angina symptoms and were free from requiring coronary artery bypass grafting in the first or second years. To decrease MACE, DAPT was found to be essential and recommended for at least 18 months for IS-CTO PCI.

Release mechanisms and applications of drug delivery systems for extended-release

INTRODUCTION

Drug delivery systems with extended-release profiles are ideal in improving patient compliance with enhanced efficacy. To develop devices capable of a prolonged delivery kinetics, it is crucial to understand the various underlying mechanisms contributing to extended drug release and the impact thereof on modulating the long-term performance of such systems in a practical application environment.

AREAS COVERED

This review article intends to provide a comprehensive summary of release mechanisms in extended-release drug delivery systems, particularly polymer-based systems; however, other material types will also be mentioned. Selected current research in the delivery of small molecule drugs and macromolecules is highlighted. Emphasis is placed on the combined impact of different release mechanisms and drug properties on the long-term release kinetics in vitro and in vivo.

EXPERT OPINION

The development of drug delivery systems over an extended duration is promising but also challenging when considering the numerous interrelated delivery-related parameters. Achieving a well-controlled extended drug release requires advanced techniques to minimize burst release and lag phase, a better understanding of the dynamic interrelationship between drug properties and release profiles over time, and a thorough elucidation of the impact of multiple in vivo conditions to methodically evaluate the eventual clinical efficacy.

Clinical Outcomes of Drug-Eluting versus Bare-Metal In-Stent Restenosis after the Treatment of Drug-Eluting Stent or Drug-Eluting Balloon: A Systematic Review and Meta-Analysis

Background

Although drug-eluting stents (DES) have reduced the rates of in-stent restenosis (ISR) compared with bare-metal stents (BMS), DES related ISR (DES-ISR) still occurs and outcomes of DES-ISR remain unclear. The objective of this meta-analysis was to investigate the long-term clinical outcomes of patients with DES-ISR compared with patients with BMS related ISR (BMS-ISR) after the treatment of DES or drug-eluting balloon (DEB). Methods and results. We searched the literature in the main electronic databases including PUBMED, EMBASE, Cochrane Library, and Web of Science. The primary endpoints were target lesion revascularization (TLR) and target vessel revascularization (TVR). The secondary endpoints included all cause death (ACD), cardiac death (CD), myocardial infarction (MI), stent thrombosis or re-in-stent restenosis (ST/RE-ISR), and major adverse cardiovascular events (MACEs). A total of 19 studies with 6256 participants were finally included in this meta-analysis. Results showed that the rates of TLR (P < 0.00001), TVR (P < 0.00001), CD (P=0.02), ST/RE-ISR (P < 0.00001), and MACEs (P < 0.00001) were significantly higher in the DES-ISR group than in the BMS-ISR group. No significant differences were found between the two groups in the rates of MI (P=0.05) and ACD (P=0.21).

Conclusions

Our study demonstrated that patients with DES-ISR had worse clinical outcomes at the long-term follow-up than patients with BMS-ISR after the treatment of DES or DEB, suggesting that DES and DEB may be more effective for BMS-ISR than that for DES-ISR. Positive prevention of DES-ISR is indispensable and further studies concentrating on detecting the predictors of outcomes of DES-ISR are required.

3-Year Clinical Follow-Up of the RIBS IV Clinical Trial: A Prospective Randomized Study of Drug-Eluting Balloons Versus Everolimus-Eluting Stents in Patients With In-Stent Restenosis in Coronary Arteries Previously Treated With Drug-Eluting Stents

OBJECTIVES

This study sought to compare the long-term safety and efficacy of drug-eluting balloons (DEB) and everolimus-eluting stents (EES) in patients with in-stent restenosis (ISR) of drug-eluting stents (DES).

BACKGROUND

Treatment of patients with DES-ISR remains a challenge.

METHODS

The RIBS IV (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloons vs Everolimus-Eluting Stents) trial is a prospective multicenter randomized clinical trial comparing DEB and EES in patients with DES-ISR. The pre-specified comparison of the 3-year clinical outcomes obtained with these interventions is the main objective of the present study.

RESULTS

A total of 309 patients with DES-ISR were randomized to DEB (n = 154) or EES (n = 155). At angiographic follow-up, the in-segment minimal lumen diameter was larger in the EES arm (2.03 ± 0.7 mm vs. 1.80 ± 0.6 mm; p < 0.01). Three-year clinical follow-up was obtained in all enrolled patients (100%). The combined clinical outcome measure of cardiac death, myocardial infarction and target lesion revascularization was significantly reduced in the EES arm (19 [12.3%] vs. 31 [20.1%]; p = 0.04; hazard ratio: 0.57 [95% confidence interval: 0.34 to 0.96]), driven by a lower need for target lesion revascularization (11 [7.1%] vs. 24 [15.6%]; p = 0.015; hazard ratio: 0.43 [95% confidence interval: 0.21 to 0.87]). The need for "late" (>1 year) target lesion revascularization (2.6% vs. 4%) and target vessel revascularization (4% vs. 6.6%) was similar in the 2 arms. Rates of cardiac death (3.9% vs. 3.2%), myocardial infarction (2.6% vs. 4.5%), and stent thrombosis (1.3% vs. 2.6%) at 3 years were also similar in both arms.

CONCLUSIONS

The 3-year clinical follow-up of this randomized clinical trial demonstrates that in patients with DES-ISR, EES reduce the need for repeat interventions compared with DEB. (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloons vs Everolimus-Eluting Stents [RIBS IV]; NCT01239940).

Drug-coated balloon treatment in coronary artery disease: Recommendations from an Asia-Pacific Consensus Group

Coronary artery disease (CAD) is currently the leading cause of death globally, and the prevalence of this disease is growing more rapidly in the Asia-Pacific region than in Western countries. Although the use of metal coronary stents has rapidly increased thanks to the advancement of safety and efficacy of newer generation drug eluting stent (DES), patients are still negatively affected by some the inherent limitations of this type of treatment, such as stent thrombosis or restenosis, including neoatherosclerosis, and the obligatory use of dual antiplatelet therapy (DAPT) with unknown optimal duration. Drug-coated balloon (DCB) treatment is based on a leave-nothing-behind concept and therefore it is not limited by stent thrombosis and long-term DAPT; it directly delivers an anti-proliferative drug which is coated on a balloon after improving coronary blood flow. At present, DCB treatment is recommended as the first-line treatment option in metal stent-related restenosis linked to DES and bare metal stent. For de novo coronary lesions, the application of DCB treatment is extended further, for conditions such as small vessel disease, bifurcation lesions, and chronic total occlusion lesions, and others. Recently, several reports have suggested that fractional flow reserve guided DCB application was safe for larger coronary artery lesions and showed good long-term outcomes. Therefore, the aim of these recommendations of the consensus group was to provide adequate guidelines for patients with CAD based on objective evidence, and to extend the application of DCB to a wider variety of coronary diseases and guide their most effective and correct use in actual clinical practice.

Contemporary Management of Stent Failure: Part One

The occurrence of in-stent restenosis (ISR) still remains a daunting challenge in the current era, despite advancements in coronary intervention technology. The authors explore the underlying pathophysiology and mechanisms behind ISR, and describe how the use of different diagnostic tools helps to best elucidate these. They propose a simplistic algorithm to manage ISR, including a focus on how treatment strategies should be selected and a description of the contemporary technologies available. This article aims to provide a comprehensive outline of ISR that can be translated into evidence-based routine clinical practice, with the aim of providing the best outcomes for patients.

In-Stent Restenosis of Drug-Eluting Stents Compared With a Matched Group of Patients With De Novo Coronary Artery Stenosis

Drug-eluting stents (DES) significantly reduced the incidence of in-stent restenosis (ISR). However, ISR still exists in the contemporary DES era. Previously deemed to be a benign process, ISR leads to complex presentation and intervention. This study aimed to compare the presentation and outcome of DES-ISR versus de novo lesions. We performed a retrospective analysis of 11,666 patients receiving percutaneous coronary intervention from 2003 to 2017 and divided them into 2 groups by de novo stenosis and ISR. They were matched based on common cardiovascular risk factors at a 4:1 ratio, respectively. After matching, a total of 1,888 patients with 3,126 de novo lesions and 472 patients with 508 ISR lesions were analyzed. Patients with ISR presented more often with unstable angina (61% vs 45%, p <0.001) and less often with myocardial infarction (6% vs 14%, p <0.001). One-year composite major adverse cardiovascular event, defined as death, Q-wave myocardial infarction, and target vessel revascularization, was 10% in the de novo group and 17% in the ISR group (hazard ratio 1.98, 95% confidential interval 1.58 to 2.46, p <0.001). After adjusting for myocardial infarction presentation, hazard ratio of major adverse cardiovascular events was still higher for the ISR group at 1 year (2.03, 95% confidential interval 1.62 to 2.55, p <0.001). ISR of DES remains a therapeutic challenge and leads to complex presentation and worse outcomes compared with matched de novo patients. These data show that DES-ISR demands better appreciation and prevention with more precise stent technique and should motivate the continued development of fully bioresorbable scaffolds.

Impact of hyperuricemia on clinical outcomes after percutaneous coronary intervention for in-stent restenosis

Background

There have been limited data on the impact of hyperuricemia on long-term clinical outcomes after percutaneous coronary intervention (PCI) for in-stent restenosis (ISR).

Methods

From January 2009 to July 2015, 317 patients who underwent repeat PCI for ISR were divided into two groups: patients with normal serum uric acid (UA) levels (normal UA group) and patients with higher serum UA levels (higher UA group). The higher UA group included patients with serum UA levels > 6.8 mg/dL or patients who were taking anti-hyperuricemic medication.

Results

During a median follow-up period of 1088 days, the cumulative incidence rates of major adverse event (MAE), including a composite of all-cause death, non-fatal myocardial infarction, and any revascularization, were similar between the two groups (higher UA 36.4% vs. normal UA 29.9%, p = 0.389, log-rank p = 0.367). Follow-up angiographic data showed similar outcomes of late lumen loss (0.8 ± 0.9 mm vs. 0.8 ± 1.1 mm, p = 0.895) and binary restenosis rate (28.1% vs. 34.7%, p = 0.622). Multivariate Cox regression analysis indicated higher levels of low-density lipoprotein cholesterol (hazard ratio [HR] 1.011, 95% confidence interval [CI] 1.003–1.019, p = 0.006) and lower left ventricular ejection fraction (HR 0.972, 95% CI 0.948–0.996, p = 0.022), but not UA levels, to be the independent risk predictors of MAE.

Conclusion

Hyperuricemia is not associated with poor clinical outcomes after repeat PCI for ISR lesions.

Electronic supplementary material

The online version of this article (10.1186/s12872-018-0840-2) contains supplementary material, which is available to authorized users.

Neointimal Modification With Scoring Balloon and Efficacy of Drug-Coated Balloon Therapy in Patients With Restenosis in Drug-Eluting Coronary Stents: A Randomized Controlled Trial

OBJECTIVES

The aim of this study was to compare neointimal modification with scoring balloon pre-dilation before drug-coated balloon (DCB) versus DCB standard therapy in patients presenting with drug-eluting stent (DES) restenosis.

BACKGROUND

DCB angioplasty for the treatment of coronary drug-eluting stent restenosis has demonstrated encouraging results. The efficacy of DCB treatment relies on rapid initial drug transfer and tissue retention of the antiproliferative drug. Neointimal modification with scoring balloon pre-dilation may enhance the efficacy of DCB therapy.

METHODS

In this randomized, open-label, active-controlled trial, 252 patients with clinically significant DES restenosis were enrolled at 4 centers in Germany. Patients undergoing DCB angioplasty were randomly assigned to treatment with scoring balloon pre-dilation or standard therapy. The primary endpoint of the study was in-segment percentage diameter stenosis on 6- to 8-month follow-up angiography. The secondary endpoints included binary angiographic restenosis and late lumen loss on follow-up angiography, the combined incidence of death or myocardial infarction, target lesion revascularization, and target lesion thrombosis at 1 year.

RESULTS

Follow-up angiographic data at 6 to 8 months were available for 203 patients (80.6%). Scoring balloon pre-dilation compared with standard therapy showed significantly lower rates with respect to the primary endpoint (35.0 ± 16.8% vs. 40.4 ± 21.4%; p = 0.047) and binary angiographic restenosis (18.5% vs. 32.0%; p = 0.026). Late lumen loss was numerically lower after scoring balloon pre-dilation compared with standard therapy (0.31 ± 59 mm vs. 0.41 ± 0.74 mm; p = 0.27). There was no difference between the groups in the incidence of death or myocardial infarction (4.0% vs. 3.4%; p = 0.73). Scoring balloon versus standard therapy showed comparable rates of target lesion revascularization (16.2% vs. 21.8%; p = 0.26). No target lesion thrombosis occurred out to 1 year.

CONCLUSIONS

In patients presenting with drug-eluting stent restenosis, neointimal modification with scoring balloon improves the antirestenotic efficacy of DCB therapy. (Intracoronary Stenting and Angiographic Results: Optimizing Treatment of Drug Eluting Stent In-Stent Restenosis 4 [ISAR-DESIRE 4]; NCT01632371).

Percutaneous coronary intervention of lesions with in-stent restenosis: A report from the ADAPT-DES study

BACKGROUND

There is a paucity of data from large contemporary cohorts of patients with in-stent restenosis (ISR) treated with drug-eluting stents (DESs), and no studies have examined the impact of high platelet reactivity (HPR) on the occurrence of ischemic events after ISR percutaneous coronary intervention (PCI) with DESs. We sought to report outcomes after PCI of ISR lesions and its association with HPR.

METHODS

Patients in the prospective, multicenter ADAPT-DES study were stratified according to whether they had ISR versus non-ISR PCI. Two-year outcomes were compared between the groups using Cox proportional hazards models. HPR was defined as on-clopidogrel P2Y12 platelet reaction units >208 as measured by the VerifyNow assay; target vessel failure (TVF) was defined as the composite of all-cause death, myocardial infarction, or ischemia-driven target vessel revascularization.

RESULTS

Among the 8,582 patients included in the ADAPT-DES study, 840 (9.8%) patients underwent successful ISR PCI. ISR PCI was independently associated with a higher 2-year risk of TVF (adjusted hazard ratio [HR] 1.95; 95% CI 1.68-2.27; P<.001) and stent thrombosis (adjusted HR 1.95; 95% CI 1.08-3.51; P=.027) but not bleeding (adjusted HR 0.94; 95% CI 0.73-1.21; P=.64). There was no statistical interaction between HPR and ISR versus non-ISR PCI in regard to TVF (adjusted P_interaction=.81).

CONCLUSIONS

ISR PCI is associated with a considerably higher risk of 2-year adverse ischemic events, with HPR conferring similar risk in ISR and non-ISR PCI. More effective therapeutic strategies for managing ISR lesions are necessary.

Comparative assessment of three drug eluting stents with different platforms but with the same biodegradable polymer and the drug based on quantitative coronary angiography and optical coherence tomography at 12-month follow-up

The aim of this study was to compare neointima proliferation in three drug-eluting stents (DES) produced by the same company (Balton, Poland) which are covered with a biodegradable polymer and elute sirolimus (concentration: 1.0 and 1.2 µg/mm²), but have different stent platforms and strut thickness: stainless steel Prolim^® (115 µm) and BiOSS LIM^® (120 µm) and cobalt-chromium Alex^® (70 µm). We analyzed data of patients with quantitative coronary angiography (QCA) and optical coherence tomography (OCT) at 12 months from BiOSS LIM Registry, Prolim Registry and Alex OCT clinical trial. There were 56 patients enrolled, in whom 29 Prolim^® stents were deployed, in 11-BiOSS LIM^® and in 16-Alex stents. The late lumen loss was the smallest in Prolim^® subgroup (0.26 ± 0.17 mm) and did not differ from Alex^® subgroup (0.28 ± 0.47 mm). This parameter was significantly bigger in BiOSS^® subgroup (0.38 ± 0.19 mm; p < 0.05). In OCT analysis there was no statistically significant difference between Prolim^® and Alex^® subgroups in terms of mean neointima burden (24.6 ± 8.6 vs. 19.27 ± 8.11%) and neointima volume (28.16 ± 15.10 vs. 24.51 ± 17.64 mm³). In BiOSS^® group mean neointima burden (30.9 ± 6.2%) and mean neointima volume (44.9 ± 4.9 mm³) were significantly larger. The morphological analysis revealed that in most cases in all groups the neointima was homogenous with plaque presence only around stent struts. In the QCA and OCT analysis regular DES (Prolim^® and Alex^®) obtained similar results, whereas more pronounced response from the vessel wall was found in the BiOSS^® subgroup.

Predictors of Recurrent In-Stent Restenosis After Paclitaxel-Coated Balloon Angioplasty

BACKGROUND

Although paclitaxel-coated balloon (PCB) angioplasty is an effective procedure for in-stent restenosis (ISR) after coronary stenting, recurrent ISR after PCB angioplasty still occurs. The aim of this study was to evaluate the predictors of recurrent ISR after PCB angioplasty for ISR.Methods and Results:A total of 157 ISR lesions treated with PCB angioplasty from January 2014 to May 2015 were retrospectively examined. Recurrent ISR was judged on 6-month follow-up angiography. Clinical, angiographic and procedural parameters were evaluated as possible predictors of recurrent ISR. Recurrent ISR occurred in 13.9% of lesions after PCB angioplasty. On multivariate analysis the following independent predictors of recurrent ISR were identified: (1) smaller acute gain after initial ballooning (OR, 3.06; 95% CI: 1.08-8.71; P=0.04); (2) geographic mismatch between PCB position and initial ballooning (OR, 5.59; 95% CI: 1.64-19.1; P=0.006); and (3) use of percutaneous transluminal coronary rotational atherectomy (PTCRA) at primary percutaneous coronary intervention (PCI; OR, 5.53; 95% CI: 1.89-16.2; P=0.002).

CONCLUSIONS

Optimal expansion at initial ballooning before PCB angioplasty and careful positioning of PCB are important technical tips to prevent recurrent ISR after PCB angioplasty. Recurrent ISR occurred more frequently in severely calcified lesions that required PTCRA at primary PCI.

Unimolecular Micelle-Based Hybrid System for Perivascular Drug Delivery Produces Long-Term Efficacy for Neointima Attenuation in Rats

At present, there are no clinical options for preventing neointima-caused (re)stenosis after open surgery such as bypass surgery for treating flow-limiting vascular disease. Perivascular drug delivery is a promising strategy, but in translational research, it remains a major challenge to achieve long-term (e.g., > 3 months) anti(re)stenotic efficacy. In this study, we engineered a unique drug delivery system consisting of durable unimolecular micelles, formed by single multiarm star amphiphilic block copolymers with only covalent bonds, and a thermosensitive hydrogel formed by a poly(lactide-co-glycolide)-poly(ethylene glycol)-poly(lactide-co-glycolide) triblock copolymer (abbreviated as triblock gel) that is stable for about 4 weeks in vitro. The drug-containing unimolecular micelles (UMs) suspended in Triblock gel were able to sustain rapamycin release for over 4 months. Remarkably, even 3 months after perivascular application of the rapamycin-loaded micelles in Triblock gel in the rat model, the intimal/medial area ratio (a restenosis measure) was still 80% inhibited compared to the control treated with empty micelle/gel (no drug). This could not be achieved by applying rapamycin in Triblock gel alone, which reduced the intimal/medial ratio only by 27%. In summary, we created a new UM/Triblock gel hybrid system for perivascular drug delivery, which produced a rare feat of 3-month restenosis inhibition in animal tests. This system exhibits a real potential for further translation into an anti(re)stenotic application with open surgery.

Restenosis of the Coronary Arteries: Past, Present, Future Directions

Restenosis is a pathologic response to vascular injury, characterized by neointimal hyperplasia and progressive narrowing of a stented vessel segment. Although advances in stent design have led to a dramatic reduction in the incidence of restenosis, it continues to represent the most common cause of target lesion failure following percutaneous coronary intervention. Efforts to maximize restenosis prevention, through careful consideration of modifiable risk factors and an individualized approach, are critical, as restenosis, once established, can be particularly difficult to treat. Novel approaches are on the horizon that have the potential to alter the natural history of this stubborn disease.

Treatment options for stent restenosis: insights from intracoronary imaging, clinical trials, and registries

Although drug-eluting stents (DES) have markedly reduced the incidence of stent restenosis (SR), the increased number and complexity of percutaneous coronary interventions performed worldwide explain the sustained prevalence of SR. Intracoronary imaging techniques remain essential tools to unravel the underlying mechanical causes potentially leading to SR. Current clinical trial data suggest that DES are the most effective therapy for the management of both bare-metal stents SR and DES-SR. In this setting, however, drug-eluting balloons represent a valid therapeutic alternative with the attractive advantage of not requiring the implantation of an additional metallic layer. In this review, we will discuss trial data on the historical evolution and the evidence supporting currently available therapeutic modalities for patients with bare-metal stents SR or DES-SR.

Drug-coated balloons for the treatment of in-stent restenosis in diabetic patients: A review of currently available scientific data

After the introduction of drug eluting stent (DES) the rate of in-stent restenosis (ISR) has decreased if compared to the BMS era; however, treatment of patients with ISR remained a major issue for the interventional cardiologist. DES has been largely used with good results also as second layer for the treatment of ISR, but the overall percentage of patients suffering from restenosis still remains high, especially in some subgroups of patients as ones with diabetes mellitus (DM). In this clinical scenario, drug coated balloon (DCB) has been gaining an important role for the treatment of ISR. In fact, it allows to release an antiproliferative drug, namely paclitaxel, without the addition of a second metallic strut, which can lead to a persistent inflammatory stimulus and further narrow the vessel. This could be an advantage in patients with an already increased systemic inflammatory burden and stiffer vessels as those with DM. Despite differences in terms of efficacy and safety between DES and DCB have already been evaluated in different clinical trials, just few of these focused on diabetic patients. The aim of this paper is to review the available data for treatment of ISR both with DES, DCB, and a comparison between these two devices, in patients affected by DM. © 2017 Wiley Periodicals, Inc.

Drug-eluting balloon versus second-generation drug-eluting stent for the treatment of restenotic lesions involving coronary bifurcations

AIMS

To report clinical outcomes in patients treated with drug-eluting balloon (DEB) versus second-generation drug-eluting stent (DES) for in-stent restenosis (ISR) involving a bifurcation lesion.

METHODS AND RESULTS

Between February 2007 and November 2012, 167 bifurcation restenoses in 158 patients were treated with either DEB (n=73) or second-generation DES (n=85). The EuroSCORE was significantly higher in the DEB group (4.2±3.8 vs. 2.8±2.1, p=0.004). Regarding restenosed stent type, second-generation DES was more frequently seen in the DEB group (26.9% vs. 6.7%, p<0.001). In this group, there was also a trend towards more frequent stenting for a previous ISR (stent-in-stent) as compared with the DES group (25.6% vs. 15.6%, p=0.074). Over a median follow-up period of 701 days, there was no significant difference in major adverse cardiac events (MACE), defined as cardiac death, myocardial infarction including periprocedural myocardial infarction, target vessel revascularisation, between the two groups (p=0.585). Independent predictors of MACE on multivariate Cox regression analysis included stent-in-stent (HR: 2.16; 95% CI: 1.11 to 4.20; p=0.023) and true bifurcation lesions (HR: 2.98; 95% CI: 1.45 to 6.14; p=0.001).

CONCLUSIONS

DEB for bifurcation restenosis may be an acceptable treatment option, especially in cases where repeat stenting has not already been performed for the treatment of a previous restenosis.

Recurrent in-stent restenosis, certainty of its origin, uncertainty about treatment

Treatment of recurrent in-stent restenosis is a real brainteaser for the interventional cardiologist who cannot resort to the guidelines to have indications about the type of treatment to be preferred. The use of intracoronary imaging may provide insights into the underlying mechanisms of this complication and use of drug-coated balloons may be a valid alternative and especially a thoughtful treatment when the repeated and perseverant use of drug-eluting stents clearly fails. In this setting, we present a review of the literature about this interesting topic, going deep into the heart of the problem, its origin and possible treatment options.

Understanding and managing in-stent restenosis: a review of clinical data, from pathogenesis to treatment

The lumen diameter reduction after percutaneous coronary intervention (PCI) is well known as "restenosis". This phenomenon is due to vessel remodeling/recoil in case of no-stent strategy or, in case of stent employ, "neointimal proliferation" that consists in an excessive tissue proliferation in the luminal surface of the stent otherwise by a further new-occurring atherosclerotic process called "neoatherosclerosis". The exact incidence of in-stent restenosis (ISR) is not easy to determine caused by different clinical, angiographic and operative factors. In the pre-stent era the occurrence of restenosis ranged between 32-55% of all angioplasties, and drop to successively 17-41% in the bare metal stents (BMS) era. The advent of drug-eluting stent (DES), especially 2nd generation, and drug-coated balloon (DCB) further reduce restenosis rate until <10%. We here review the main characteristics of this common complication of coronary interventions, from its pathogenesis to the most appropriate treatment strategy.

Efficacy of various percutaneous interventions for in-stent restenosis: comprehensive network meta-analysis of randomized controlled trials

BACKGROUND

In-stent restenosis (ISR) remains a difficult problem in interventional cardiology. The relative efficacy and safety of available interventions is not clear. We aimed to perform a network meta-analysis using both direct evidence and indirect evidence to compare all available interventions.

METHODS AND RESULTS

We systematically searched electronic databases for randomized trials comparing ≥2 treatments for ISR. A network meta-analysis was performed using a Bayesian approach. Eleven treatments were compared in 31 studies with 8157 patient-years follow-up. Compared with balloon angioplasty, everolimus-eluting stent (hazard ratio [95% credibility interval], 0.13 [0.048-0.35]), paclitaxel-eluting balloon (0.32 [0.20-0.49]), paclitaxel-eluting cutting balloon (0.054 [0.0017-0.5]), paclitaxel-eluting stent (0.39 [0.24-0.62]), and sirolimus-eluting stent (0.32 [0.18-0.50]) are associated with lower target vessel revascularization. Balloon angioplasty is not different from cutting balloon (0.73 [0.31-1.5]), excimer laser (0.89 [0.29-2.7]), rotational atherectomy (0.96 [0.53-1.7]), and vascular brachytherapy (0.60 [0.35-1.0]). In drug-eluting stent ISR, balloon angioplasty was inferior to everolimus-eluting stent (0.19 [0.049-0.76]), paclitaxel-eluting balloon (0.43 [0.18-0.80]), paclitaxel-eluting stent (0.35 [0.13-0.76]), and sirolimus-eluting stent (0.36 [0.11-0.86]) for target vessel revascularization. There was no difference between treatments in probable or definitive stent thrombosis. The results of binary restenosis and target lesion revascularization were similar. Paclitaxel-eluting cutting balloon, everolimus-eluting stent, and paclitaxel-eluting balloon have the highest probability of being in the top 3 treatments based on low target lesion revascularization, but there was no statistical significant difference between them.

CONCLUSIONS

Balloon angioplasty is inferior to all drug-eluting treatments for ISR, including drug-eluting stent ISR. Drug-eluting stent, particularly everolimus-eluting stent, or paclitaxel-eluting cutting balloon and paclitaxel-eluting balloon should be preferred for treating ISR.