Intravascular brachytherapy versus drug-eluting stents for the treatment of patients with drug-eluting stent restenosis

The contemporary use of intracoronary brachytherapy for instent restenosis: A review

In-stent restenosis (ISR) has been a major limitation in interventional cardiology and constitutes nearly 10 % of all percutaneous coronary interventions in the United States. Drug-eluting stent (DES) restenosis proves particularly difficult to manage and poses a high risk of recurrence and repeat intervention. Intra-coronary brachytherapy (IBT) has been traditionally viewed as a potential treatment modality for ISR. However, its use was hindered by procedural complexity, cost, and the advent of newer-generation DES. Recent data suggests promising results regarding IBT for the treatment of resistant DES-ISR. This review addresses the mechanism of action of IBT, procedural details, and associated risks and complications of its use. It will also highlight the available clinical evidence supporting the use of IBT and the future directions of its utilization in the treatment of ISR.

Drug-Eluting Stent Restenosis: Modern Approach to a Classic Challenge

In-stent restenosis (ISR) is a recognized complication following percutaneous coronary intervention in which the luminal diameter is narrowed through neointimal hyperplasia and vessel remodeling. Although rates of ISR have decreased in most recent years owing to newer generation drug-eluting stents, thinner struts, and better intravascular imaging modalities, ISR remains a prevalent dilemma that proves to be challenging to manage. Several factors have been proposed to contribute to ISR formation, including mechanical stent characteristics, technical factors during the coronary intervention, and biological aspects of drug-eluting stents. Presentation of ISR can range from asymptomatic to late myocardial infarction and could be difficult to differentiate from acute thrombus formation. No definite guidelines are present on the management of ISR. In this review, we will discuss the mechanisms underlying ISR and provide insight into patient-related and procedural risk factors contributing to ISR, in addition to highlighting common treatment approaches utilized in the management of ISR.

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.

Liposomal Nanocarriers Designed for Sub-Endothelial Matrix Targeting under Vascular Flow Conditions

Vascular interventions result in the disruption of the tunica intima and the exposure of sub-endothelial matrix proteins. Nanoparticles designed to bind to these exposed matrices could provide targeted drug delivery systems aimed at inhibiting dysfunctional vascular remodeling and improving intervention outcomes. Here, we present the progress in the development of targeted liposomal nanocarriers designed for preferential collagen IV binding under simulated static vascular flow conditions. PEGylated liposomes (PLPs), previously established as effective delivery systems in vascular cells types, served as non-targeting controls. Collagen-targeting liposomes (CT-PLPs) were formed by conjugating established collagen-binding peptides to modified lipid heads via click chemistry (CTL), and inserting them at varying mol% either at the time of PLP assembly or via micellar transfer. All groups included fluorescently labeled lipid species for imaging and quantification. Liposomes were exposed to collagen IV matrices statically or via hemodynamic flow, and binding was measured via fluorometric analyses. CT-PLPs formed with 5 mol% CTL at the time of assembly demonstrated the highest binding affinity to collagen IV under static conditions, while maintaining a nanoparticle characterization profile of ~50 nm size and a homogeneity polydispersity index (PDI) of ~0.2 favorable for clinical translation. When liposomes were exposed to collagen matrices within a pressurized flow system, empirically defined CT-PLPs demonstrated significant binding at shear stresses mimetic of physiological through pathological conditions in both the venous and arterial architectures. Furthermore, when human saphenous vein explants were perfused with liposomes within a closed bioreactor system, CT-PLPs demonstrated significant ex vivo binding to diseased vascular tissue. Ongoing studies aim to further develop CT-PLPs for controlled targeting in a rodent model of vascular injury. The CT-PLP nanocarriers established here show promise as the framework for a spatially controlled delivery platform for future application in targeted vascular therapeutics.

Is Coronary Brachytherapy Staging a Comeback for the Treatment of In-Stent Restenosis?

PURPOSE OF REVIEW

The catheter-based coronary intervention has become a well-established therapeutic modality for obstructive coronary artery disease. However, in-stent restenosis remains a significant limitation of coronary intervention despite the use of newer devices. Intravascular brachytherapy was introduced to treat recurrent in-stent restenosis but only modestly adopted. This review will discuss the mechanism of intracoronary brachytherapy, available clinical evidence of brachytherapy in recurrent in-stent restenosis treatment, and the future of coronary brachytherapy in coronary intervention.

RECENT FINDINGS

Drug-eluting stents have an inherent limitation as they leave a permanent metal layer inside an artery when deployed. Recently, drug-coated balloon technology has emerged to treat coronary artery disease as a combination of balloon angioplasty and local drug delivery without leaving a metal layer behind. Recent European guidelines recommended using drug-coated balloons when treating in-stent restenosis treatment, while the US guidelines have not yet addressed the use of drug-coated balloons in such cases. Coronary brachytherapy is a valuable addition to treat these challenging diseases despite several logistic issues. If there are newer technologies with easier setup, such as drug-coated balloons, coronary brachytherapy resurgence is improbable in the contemporary era, although it may not become obsolete.

Impact of Intravascular Brachytherapy on Patient-Reported Outcomes in Patients with Coronary Artery Disease

BACKGROUND

Intravascular brachytherapy (VBT) is an established treatment for the management of in-stent restenosis (ISR). However, whether VBT is associated with improved patient reported outcomes unknown.

METHODS

We evaluated 51 consecutive patients undergoing VBT in one or more coronary arteries from January 2018 to September 2019. Data on baseline characteristics, procedural outcomes and adverse events were obtained. All patients completed the Seattle Angina Questionnaire - 7 (SAQ-7) form before and after VBT at 1 month and 6 months.

RESULTS

The mean age was 69 ± 9 years and 29 (57%) of patients were males. Procedural success was 94.1%. The mean summary SAQ-7 score improved significantly (53.2 ± 21 vs. 83 ± 19, p < .001) at 30-days. The median Quality of Life (QoL) component of SAQ-7 score was 31.3 (Interquartile Range [IQR]: 18.8, 62.5) and improved to 82.5 (IQR: 62.5, 100), p < .001 at 30 days and 87.5 [IQR: 75, 100), p < .001 at last follow up. Likewise, the median angina frequency component of the SQL-7 score pre-VBT was 55 (IQR: 45, 80) and improved significantly to 90 (IQR: 60, 100) at 30-days, p < .001 and 100 [IQR: 68.8, 100], p = .02 at last follow up. Lastly, the median activity component of the SAQ-7 score improved from 83.3 (IQR: 60-100) to 100 (IQR: 83, 100), p = .01 at 30-days. Thus, results were evident as early as 1 month and sustained at median follow up of 17 months.

CONCLUSION

VBT is associated with improvement in patient reported outcome measures at short term and long term follow up.

Combined Vascular Brachytherapy and Stenting for the Treatment of In-Stent Restenosis

In-stent restenosis (ISR) remains a therapeutic challenge in the current drug-eluting stent (DES) era. Vascular brachytherapy (VBT) is a therapeutic option for ISR, but data about the outcomes of combination therapy with VBT and stenting for ISR lesions are sparse. We retrospectively analyzed patients who presented with ISR at our institution from 2003 through 2017. Three treatment arms were compared: VBT alone, VBT plus bare-metal stent (BMS), and VBT plus DES. Clinical, procedural, and 1-year outcome data were collected. Follow-up was obtained by phone calls and clinic visits. The patient cohort included 461 patients (764 ISR lesions). Of these, 333 patients (533 lesions) were treated with VBT alone, 89 patients (158 lesions) with VBT plus BMS, and 39 patients (73 lesions) with VBT plus DES. There were no significant differences in baseline characteristics among the 3 groups except for more patients with a remote smoking history in the VBT plus BMS (43.8%) and VBT plus DES groups (56.4%), and more patients with history of peripheral vascular disease (39.5%) and congestive heart failure (27%) in the VBT plus DES group. The most common clinical presentation was unstable angina (64.6%). In the VBT plus DES group, 10.3% of patients presented with MI, versus 5.5% in the VBT alone group and 2.2% in the VBT plus BMS group. At 1-year follow-up, the VBT plus DES group had higher rates of target vessel revascularization-major adverse cardiovascular events (38.5%) than the VBT plus BMS (21.3%) and VBT alone (15.6%) groups (p = 0.002). In conclusion, in patients with ISR, combination therapy with VBT and stenting at the same setup is associated with worse outcomes at 12 months and, if possible, should be avoided.

Current Management of In-Stent Restenosis

Despite the advent of the drug-eluting stents (DES) and improved stent design, in-stent restenosis (ISR) remains a challenging problem. The currently available options for treatment of ISR include angioplasty alone, repeat stenting with DES or drug-coated balloons. Several recent studies have compared the available options for treating ISR in an attempt to identify the preferred therapeutic strategy. In this review, we will discuss the currently available therapeutic strategies for the management of patients with ISR and the evidence supporting their use.

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.

Intracoronary Brachytherapy for Recurrent Drug-Eluting Stent Failure

OBJECTIVES

The study sought to report safety and long-term clinical efficacy of intravascular brachytherapy (VBT) for recurrent drug-eluting stent in-stent restenosis (DES-ISR).

BACKGROUND

Recurrent DES-ISR remains a therapeutic challenge, and VBT has been used selectively in recurrent DES failure.

METHODS

Patients undergoing VBT for recurrent DES-ISR were enrolled from a percutaneous coronary intervention registry. Clinical, procedural, VBT, and outcome data were collected for DES-ISR treated with radiation. Follow-up was obtained by phone call and clinic visits.

RESULTS

A total of 186 patients (283 lesions) were included. Mean age was 65 ± 11 years, and 115 (61.8%) were men. Mean time to failure from last failed DES implantation was 450.65 ± 50 days. Majority (95%) had >2 episodes of target lesion revascularization (TLR). Commonest presentation of DES-ISR was unstable angina (68, 30%). All lesions were treated with balloon angioplasty followed by VBT using Beta-Cath system (Best Vascular Inc., Springfield, Virginia) with a dose of 23 to 25 Gy at 2 mm from source center. Radiation was delivered to site of ISR, without procedural adverse events, in 99% cases. Incidence of TLR was 3.3% at 6 months, 12.1% at 1 year, 19.1% at 2 years, and 20.7% at 3 years. No subacute thrombosis event was noted. One patient had late thrombosis during a 3-year follow-up.

CONCLUSIONS

VBT for recurrent DES-ISR is safe, with low recurrence rates at 12 months post-procedure, and can be safely used as an effective short-term strategy. Overtime, there is a gradual attrition in patency requiring repeat intervention.

Intracoronary brachytherapy for in-stent restenosis of drug-eluting stents

PURPOSE

Given the limited salvage options for in-stent restenosis (ISR) of drug-eluting stents (DES), our high-volume cardiac catheterization laboratory has been performing intracoronary brachytherapy (ICBT) in patients with recurrent ISR of DES. This study analyzes their baseline characteristics and assesses the safety/toxicity of ICBT in this high-risk population.

METHODS AND MATERIALS

A retrospective analysis of patients treated with ICBT between September 2012 and December 2014 was performed. Patients with ISR twice in a single location were eligible. Procedural complications included vessel dissection, perforation, tamponade, slow/absent blood flow, and vessel closure. Postprocedural events included myocardial infarction, coronary artery bypass graft, congestive heart failure, stroke, bleeding, thrombosis, embolism, dissection, dialysis, or death occurring within 72 hours. A control group of patients with 2 episodes of ISR at 1 location who underwent percutaneous coronary intervention without ICBT was identified. Unpaired t tests and χ2 tests were used to compare the groups.

RESULTS

There were 134 (78%) patients in the ICBT group with 141 treated lesions and 37 (22%) patients in the control group. There was a high prevalence of hyperlipidemia (>95%), hypertension (>95%), and diabetes (>50%) in both groups. The groups were well-balanced with respect to age, sex, and pre-existing medical conditions, with the exception of previous coronary artery bypass graft being more common the ICBT group. Procedural complication rates were low in the control and ICBT groups (0% vs 4.5%, P = .190). Postprocedural event rates were low (<5%) in both groups. Readmission rate at 30 days was 3.7% in the ICBT group and 5.4% in the control group (P = .649).

CONCLUSIONS

This is the largest recent known series looking at ICBT for recurrent ISR of DES. ICBT is a safe treatment option with similarly low rates (<5%) of procedural and postprocedural complications compared with percutaneous coronary intervention alone. This study establishes the safety of ICBT in a high-risk patient cohort.

Management of drug eluting stent in-stent restenosis: A systematic review and meta-analysis

BACKGROUND

The optimal management for coronary drug eluting stent in-stent restenosis (DES ISR) is unclear. We performed a meta-analysis of observational and randomized studies to compare the outcomes of management of DES ISR using DES, drug eluting balloon (DEB), or balloon angioplasty (BA).

METHODS

Eligible studies (25 single arm and 13 comparative, including 4 randomized studies with a total of 7,474 patients with DES ISR) were identified using MEDLINE search and proceedings of international meetings. Outcomes studied include major adverse cardiac events (MACE), target lesion revascularization (TLR), target vessel revascularization (TVR), myocardial infarction (MI), stent thrombosis (ST), and mortality. Follow-up ranged from 0.5 to 3.5 years (mean 1.4 years).

RESULTS

The rate of TLR was significantly lower in the DES (odds ratio [OR] 0.50, 95% confidence interval [CI] 0.36-0.69) and DEB (OR 0.31, 95% CI 0.18-0.55) groups compared to BA. Similarly, TVR rate was significantly lower in the DES (OR 0.55, 95% CI 0.39-0.77) and DEB (OR 0.32, 95% CI 0.18-0.58) groups compared to BA. All other outcomes were similar between the DES/BA and DEB/BA comparisons. TLR was significantly lower in the DES group compared to BA for vessels < or > 2.75 mm.

CONCLUSION

Treatment of coronary DES ISR with DES or DEB is associated with a reduction in the risk of TLR and TVR compared to BA alone. The relative risk reduction for TLR with DES is similar to DEB. DEBs have a potential role in the treatment of DES ISR by avoiding placement of another layer of stent. © 2015 Wiley Periodicals, Inc.

A journey from CABG to drug-eluting balloon

A middle aged male underwent series of percutaneous coronary intervention (PCI) of left main stenosis for Canadian cardiovascular society (CCS) IV angina. He developed recurrent severe proliferative in-stent restenosis which was treated with different available options including drug-eluting stents and finally with drug-eluting balloons. During his treatment, challenges of PCI including left main chronic total occlusion PCI, complications like coronary perforation were encountered and treated successfully.

Bioresorbable vascular scaffold for coronary in-stent restenosis: a novel concept

The management of patients with significant in-stent restenosis (ISR) with drug-eluting stent is still not well defined. Various treatment modalities include plain old balloon angioplasty (POBA), metallic stent, cutting or scoring balloon and drug-eluting balloon (DEB). Bioresorbable vascular scaffold (BVS) is the latest technology for the treatment of de novo coronary artery lesions. The use of BVS in ISR is based on the rationale of local drug delivery as achieved by DEB without the permanent bi-layer of metal and also stabilizes dissection flaps and prevents acute recoil as provided by metallic stent. To the best of our knowledge this is the first case report of the use of BVS in patient with ISR.

In-stent restenosis of drug-eluting stents

Drug-eluting stents (DES) have emerged as an improved alternative to bare-metal stents by demonstrating reduced rates of restenosis and target lesion revascularization. This emergence has led to the unrestricted use of DES for various indications and lesions, and subsequently revealed DES in-stent restenosis as a novel interventional therapeutic dilemma. Recent insights regarding the patho-physiological processes and therapeutic alternatives have added to the accumulated knowledge regarding the appropriate approach to this phenomenon. This review aims to detail the mechanism and clinical presentation of, and therapeutic strategies for, the treatment of DES in in-stent restenosis.

Current treatment of in-stent restenosis. J Am Coll Cardiol. 2014;63:2659-2673. [PMID: 24632282 DOI: 10.1016/j.jacc.2014.02.545]

Management of patients with in-stent restenosis (ISR) remains an important clinical problem. Although drug-eluting stents (DES) have drastically reduced the incidence of ISR, treatment of DES-ISR is particularly challenging. ISR mainly results from aggressive neointimal proliferation, but recent data also suggest that neoatherosclerosis may play an important pathophysiological role. Intracoronary imaging provides unique insights to unravel the underlying substrate of ISR and may be used to guide repeated interventions. In this paper, we systematically reviewed clinical trial data with currently available therapeutic modalities, including DES and drug-coated balloons, in patients presenting with ISR within bare-metal stents or DES.

Long-term outcomes of drug-eluting stent therapy for in-stent restenosis versus de novo lesions

BACKGROUND

Drug-eluting stents (DES) are currently the most popular treatment modality for restenosis in bare metal stents and DES. This study compares risks of adverse cardiovascular events between DES-treated in-stent restenosis (ISR) and de novo lesions, an area that has not been systematically studied thus far.

METHODS AND RESULTS

One thousand three hundred consecutive ISR patients were compared with 27,211 patients with de novo lesions who underwent DES treatment during the same period at the Fu Wai Hospital in Beijing. Angiographic success rate was similar between the ISR and de novo groups (98.0% vs. 98.2%; P = 0.61). Using logistic regression to derive the propensity score model, 1,266 matched patient pairs were compared. In this adjusted model, the rate of target lesion revascularization (TLR) was significantly higher in the ISR group (19.19% vs. 2.37%; P < 0.01) during an average 17-month follow-up, while rates of cardiac death and myocardial infarction (MI) were similar (0.71% vs. 0.79%; P = 0.93 and 3.48% vs. 1.26%; P = 0.13, respectively) between groups. In multivariate regression analysis, ISR was predictive of TLR, but not of cardiac death and MI.

CONCLUSION

Compared with those with de novo lesions, patients with ISR had a higher revascularization rate after DES treatment but no significant difference in rates of cardiac death and MI.

Treatment of sirolimus-eluting stent restenosis: additional stent, balloon angioplasty, and coronary artery bypass graft

OBJECTIVE

Sirolimus-eluting stent (SES) has shown a significant efficacy in reducing restenosis after percutaneous coronary interventions. However, an increase in total number of SES use along with targeting more complex lesions generated a large number of SES restenosis. This study aimed to investigate the clinical and angiographic outcomes of different revascularization strategies for SES restenosis.

METHODS AND RESULTS

A total of 176 lesions in 149 patients were included in the study. Fifteen patients underwent coronary artery bypass graft surgery (CABG group) and the remaining patients were treated with percutaneous coronary intervention (PCI). Stent reimplantation was performed in 88 patients (Stent group), whereas 46 patients received balloon therapy (Balloon group). Among 176 lesions, major cardiac adverse event (MACE) occurred in 41 lesions (23.3%) during a median follow-up of 310 days (interquartile range: 146-517 days). The Kaplan-Meier method with a log-rank test revealed no significant difference in MACE rates between the three groups (6%, 25%, 26%, p = 0.13; CABG group, Stent group, Balloon group, respectively). However, when the Balloon group and Stent group were combined together as a PCI group, PCI group had a significantly higher rate of MACE compared with the CABG group (p = 0.04). In addition, angiographic restenosis was significantly less prevalent in the CABG group when compared with the other two groups (8%, 57%, 46%, p = 0.006; CABG group, Stent group, Balloon group, respectively).

CONCLUSIONS

CABG surgery for patients with SES restenosis is associated with the better clinical outcomes as well as better angiographic outcomes when compared with that of PCI.

Clinical Outcomes and Treatment After Drug-Eluting Stent Failure

Background—

The optimal percutaneous treatment of drug-eluting stent (DES) in-stent restenosis (ISR) and the correlates for recurrent DES ISR remain unclear.

Methods and Results—

From 2003 to 2008, 563 patients presenting with recurrent symptoms of ischemia and angiographic ISR after DES implantation were included. Of these, 327 were treated with re-DES (58.1%), 132 underwent vascular brachytherapy (23.4%), and 104 were treated with conventional balloon angioplasty (18.5%). Variables associated with target lesion revascularization at 1 year were explored by individual proportional hazard models. This population presents a high prevalence of comorbidities, including diabetes (43.7%), previous myocardial infarction (MI) (45.8%), coronary bypass graft surgery (39.2%), chronic renal failure (18.8%), and heart failure (17.3%). Baseline clinical characteristics were balanced among the 3 groups; however, patients undergoing vascular brachytherapy presented with more complex lesions and a higher prevalence of prior stent/vascular brachytherapy failure than did the rest of the population. The overall incidence of recurrent DES failure at 1-year follow-up was 12.2%, which was similar among the 3 groups ( P =0.41). The rate of the composite end point (death, Q-wave-MI and target lesion revascularization) at 1-year follow-up was 14.1% for re-DES, 17.5% for vascular brachytherapy, and 18.0% for conventional balloon angioplasty ( P =0.57). After univariable analysis tested the traditional known covariates related to ISR, none of them were associated with repeat target lesion revascularization.

Conclusions—

Recurrence of ISR after DES treatment failure is neither infrequent nor benign, and optimal therapy remains unclear and challenging. Given the absence of traditional risk factors for ISR in this population, further research is required to elucidate both the correlates involved in DES ISR and the optimal treatment for this condition.

Radiation therapy for dialysis access stenosis: unfulfilled promise or false expectations

Hemodialysis vascular access dysfunction is a major cause of morbidity and hospitalization in the hemodialysis population at a cost of well over $1 billion per annum. Venous stenosis (due to venous neointimal hyperplasia [VNH]) is the most common cause of polytetrafluroethylene PTFE) dialysis access graft and arteriovenous fistula (AVF) failure. Despite the magnitude of the clinical problem, however, there are currently no effective therapies for this condition. We and others have previously demonstrated that VNH in PTFE dialysis grafts and AVF is composed of smooth muscle cells/myofibroblasts, endothelial cells within neointimal microvessels, and peri-graft macrophages. Radiation therapy blocks the proliferation and activation of all these cell types. The current review will dissect out the available in vitro, experimental, and clinical data on the use of radiation therapy for vascular stenosis in general, and for dialysis access dysfunction in particular. It is important to try and identify whether there is still a role for radiation therapy in this specific clinical setting. We believe that this is a critically important question to answer in view of the huge unmet clinical need that is currently associated with hemodialysis vascular access dysfunction.

Long-term outcomes after the percutaneous treatment of drug-eluting stent restenosis

OBJECTIVES

This study sought to evaluate the long-term angiographic and clinical outcomes after the treatment of drug-eluting stent in-stent restenosis (DES-ISR) based on the angiographic pattern of restenosis.

BACKGROUND

Long-term outcomes after percutaneous treatment of DES-ISR are unclear.

METHODS

This study performed a retrospective analysis of 481 consecutive de novo DES-ISR lesions (n = 392) treated percutaneously between August 2002 and July 2007. The lesions were divided based on the pattern of restenosis: focal (305; 63.4%), diffuse (120; 24.9%), and occlusive (56; 11.6%).

RESULTS

The majority (65%) of patients had angina or ischemia on presentation and 13% had an acute coronary syndrome. Angiographic follow-up after treatment of DES-ISR was available in 65.5% of lesions. A second angiographic restenosis occurred in 29.1% of the focal group, 45.8% (p = 0.007) of the diffuse, and 65.6% (p < 0.0001) of the occlusive. The pattern of DES-ISR predicted the pattern of recurrence: occlusive reoccluded in 66.7%; diffuse recurred as diffuse or occlusive in 57.9%; focal as focal in 67.2%. During a median follow-up of 2.97 years (interquartile range: 2.37 to 3.89), major adverse cardiac events occurred in 32.8% of patients with no significant differences among the focal, diffuse, and occlusive groups (30.9%, 38.7%, 31.1%; p = 0.38). Diffuse restenosis was associated with a significantly higher target lesion revascularization rate compared with focal (27.1% vs. 15.8%; p = 0.008). A disparity between restenosis (65.6%) and target lesion revascularization (18.5%) rates for occlusive DES-ISR suggests that as many recurrent restenoses were occlusive, they were not retreated.

CONCLUSIONS

DES-ISR identifies a high-risk cohort that is at an increased risk of events, in particular repeat revascularization, during long-term follow-up. The initial pattern of restenosis is the most important predictor of recurrent restenosis or the need for subsequent reintervention.

Usefulness of coronary pressure measurement for functional evaluation of drug-eluting stent restenosis

Despite the widespread adoption of drug-eluting stent (DES) implantation, the optimal treatment of DES failures remains challenging. The present study evaluated the relation between quantitative angiography and the fractional flow reserve (FFR) in restenotic lesions after DES implantation and the efficacy of FFR in determining whether to treat these lesions. To assess their functional significance, the coronary pressure-derived FFR was measured in 50 DES restenotic lesions (49 patients). Additional intervention was performed in lesions with a FFR <0.8. Major adverse cardiac events were assessed at 12 months after the reintervention procedure. The mean percent diameter stenosis (%DS) was 58 ± 13%. Of the 50 lesions, 20 (40%) were deferred without additional intervention. The FFR and %DS had a negative correlation (r = -0.61, p <0.001). However, when only the lesions with diffuse-type restenosis (15 lesions) were analyzed, the degree of correlation decreased (r = -0.56, p = 0.12). Although most lesions (89%) with a %DS of ≥70 had significant functional ischemia, among 41 lesions with a %DS <70, only 20 (49%) had demonstrated functional patency. The incidence of adverse events during the 12 months of follow-up after FFR-guided treatment was 18.0% (23.3% in the FFR <0.80 group and 10.0% in FFR ≥0.80 group). In conclusion, a discrepancy was found between functional ischemia measured by the FFR and the angiographic %DS, in particular, in moderate- or diffuse-type restenotic lesions after DES implantation. The outcome of FFR-guided deferral in patients with DES in-stent restenosis seems favorable.

Drug-eluting stents vs. intracoronary brachytherapy for in-stent restenosis: a meta-analysis

BACKGROUND

It has been reported that drug-eluting stents (DES) were superior to intracoronary brachytherapy (ICBT) in patients with in-stent restenosis (ISR). However, it is unknown whether there might be differences between DES and ICBT in terms of efficacy and safety in large sample size and long-term follow-up.

HYPOTHESIS

The aim of this study was to determine whether DES implantation remains favorable in large sample size and long-term follow-up when compared with ICBT among patients with ISR.

METHODS

We conducted a search in MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials without language restrictions. A meta-analysis of 1942 cases from 12 controlled trials of DES vs ICBT for ISR was performed.

RESULTS

Drug-eluting stents were significantly more effective in reducing target-vessel revascularization (TVR) (odds ratio [OR]: 0.44, 95% confidence interval [CI]: 0.23-0.81, P = 0.009) and binary restenosis (OR: 0.34, 95% CI: 0.26-0.46, P<0.00001) compared with ICBT at midterm follow-up. There were no significant differences between DES and ICBT in cardiac death, myocardial infarction (MI), and late stent thrombosis at midterm follow-up. A statistical significance has been found between the 2 groups in TVR (OR: 0.61, 95% CI: 0.43-0.86, P = 0.005) at long-term follow-up. There were no significant differences in cardiac death and MI between the 2 groups at long-term follow-up.

CONCLUSIONS

These findings provide evidence that DES is superior to ICBT for the treatment of ISR in TVR and binary restenosis reduction, but not in cardiac death, MI, and late stent thrombosis reduction. © 2011 Wiley Periodicals, Inc. Yong-Guang Lu, MD, and Yan-Mei Chen, MD, contributed equally to this work. The authors have no funding, financial relationships, or conflicts of interest to disclose.

In-stent restenosis in the drug-eluting stent era

The introduction of the drug-eluting stent (DES) proved to be an important step forward in reducing rates of restenosis and target lesion revascularization after percutaneous coronary intervention. However, the rapid implementation of DES in standard practice and expansion of the indications for percutaneous coronary intervention to high-risk patients and complex lesions also introduced a new problem: DES in-stent restenosis (ISR), which occurs in 3% to 20% of patients, depending on patient and lesion characteristics and DES type. The clinical presentation of DES ISR is usually recurrent angina, but some patients present with acute coronary syndrome. Mechanisms of DES ISR can be biological, mechanical, and technical, and its pattern is predominantly focal. Intravascular imaging can assist in defining the mechanism and selecting treatment modalities. Based upon the current available evidence, an algorithm for the treatment approaches to DES restenosis is proposed.

In-stent restenosis

The introduction of coronary stents marked a major turning point in the practice of interventional cardiology. Whereas the efficacy of balloon angioplasty was challenged both by immediate mechanical complications and by a high incidence of restenosis, coronary stents offered cardiologists a means by which to not only augment immediate procedural success, but also to reduce the incidence of restenosis following coronary intervention. However, despite technological advances and an improved understanding of the restenotic process, the overall rate of in-stent restenosis following bare metal stent implantation remains high. Although the introduction of drug-eluting stents has further reduced the incidence of restenosis, the "real-world" application of drug-eluting stents in increasingly complex lesion and patient subsets has given way to the even greater clinical challenge of managing drug-eluting stent restenosis. Although the standard treatment of bare metal stent restenosis typically involves placement of a drug-eluting stent, the optimal therapeutic approach to drug-eluting stent restenosis remains less defined. The issue of in-stent restenosis (especially following implantation of a drug-eluting stent) remains a clinical challenge, and investigation into therapeutic options remains ongoing. As technology evolves, such investigation will likely incorporate novel approaches including drug-coated balloons novel stent designs.

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

OBJECTIVES

For patients with sirolimus-eluting stent (SES) restenosis requiring reintervention, we compared a strategy of repeat SES (Cypher, Cordis, Miami Lakes, Florida) implantation with paclitaxel-eluting stent (PES) (Taxus, Boston Scientific, Natick, Massachusetts) implantation.

BACKGROUND

Despite their high anti-restenotic efficacy, the widespread utilization of SES therapy has led to a significant absolute number of patients presenting with SES treatment failure. The optimal treatment strategy for such patients remains unclear.

METHODS

The ISAR-DESIRE 2 (Intracoronary Stenting and Angiographic Results: Drug Eluting Stents for In-Stent Restenosis 2) study was a randomized, open-label, active-controlled trial conducted among 450 patients with clinically significant in-SES restenosis at 2 centers in Munich, Germany. After pre-treatment with 600 mg clopidogrel, all patients were randomly assigned to either SES or PES implantation. The primary end point was late lumen loss, based on in-stent analysis, at 6- to 8-month follow-up angiography. Secondary end points were binary angiographic restenosis (diameter stenosis >50%) at 6- to 8-month follow-up, target lesion revascularization, the composite of death or myocardial infarction, and definite stent thrombosis at 12 months.

RESULTS

Regarding anti-restenotic efficacy, there were no differences between SES and PES in late loss (0.40 +/- 0.65 mm vs. 0.38 +/- 0.59 mm; p = 0.85), binary restenosis (19.6% vs. 20.6%; p = 0.69), or target lesion revascularization (16.6% vs. 14.6%; p = 0.52). In terms of safety outcomes, the rates of death/myocardial infarction (6.1% vs. 5.8%; p = 0.86) and stent thrombosis (0.4% vs. 0.4%; p > 0.99) were also similar.

CONCLUSIONS

In cases of SES restenosis, treatment with either repeat SES or switch to PES was associated with a comparable degree of efficacy and safety. Drug resistance at an individual patient level may play a contributory role to the somewhat higher than expected late loss observed with the SES in the current study. (Intracoronary Stenting and Angiographic Results: Drug-Eluting Stents for In-Stent Restenosis 2 [ISAR-DESIRE 2]; NCT00598715).

Coronary stenting with the sirolimus-eluting stent in patients with restenosis after intracoronary brachytherapy: results from the prospective multicentre German Cypher Stent Registry

BACKGROUND

Treatment of restenosis following intracoronary brachytherapy (ICB) is still a challenging problem. Implantation of sirolimus-eluting stents (SES) in this setting may be an option to be evaluated.

METHODS AND RESULTS

We analysed the prospective multicentre SES registry, the German Cypher Stent Registry. 7,445 patients treated with an SES during percutaneous coronary intervention (PCI) were registered. Out of these patients, 61 (0.8%) were treated for restenosis after ICB: 56 patients with completed follow-up could be evaluated. Median age was 65 years, with 80% male patients. 48% of patients had a prior myocardial infarction and 25% had already coronary bypass surgery (CABG). Type B2 lesion was present in 40% and type C lesion in 22.4%. Event rates from SES implantation until 6.6 months follow-up were death 0%, myocardial infarction 3.6%, stroke 2.1%. Target vessel revascularization rate (TVR) was 16.4%, and major adverse cardiovascular or cerebral events (MACCE) or TVR occurred in 17.9% of patients. This TVR rate was higher compared with that of other patients treated with an SES: 8.4% (P = 0.04). During 65 months follow-up MACCE or TVR occurred in 44.6% of patients.

CONCLUSIONS

The treatment of lesions after ICB occurred in 0.8% out of all patients treated with an SES. Clinical event rates during early follow-up were low. However, the TVR rate was 16.4%, which was significantly higher when compared with other SES-treated patients (8.4%, P = 0.04). The treatment of restenosis after ICB with SES seems to be safe and reasonably effective; however, there might be a late catch-up phenomenon.

Angiographic patterns of drug-eluting stent restenosis and one-year outcomes after treatment with repeated percutaneous coronary intervention

Patterns of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation and outcomes after treatment have not been studied systematically in all comers. We compared patterns of ISR and outcomes of repeated percutaneous coronary intervention in consecutive patients with DES-ISR. A total of 137 patients with 182 lesions underwent repeated percutaneous coronary intervention for DES-ISR at Columbia University Medical Center from August 2004 to April 2006. DES-ISR was treated with repeated DES placement in 84% of patients and balloon angioplasty in 16%. There was 1 stent thrombosis at 30 days, and at 1 year, major adverse cardiac events occurred in 10% of patients, driven primarily by an 8% rate of target-lesion revascularization. After exclusion of 12 patients with multiple ISR lesions, data were further analyzed from 125 patients with 152 DES-ISR lesions, of which 118 were originally treated with sirolimus-eluting stents and 34 were treated with paclitaxel-eluting stents (PES-ISR). Baseline features were well matched between the 2 groups, except that patients with PES-ISR were older. A focal pattern of ISR was observed in 69.5% of patients overall. However, patients originally treated with a PES had a significantly higher frequency of diffuse-intrastent ISR in comparison with sirolimus-eluting stent ISR (30.3% vs 13.6%, p = 0.03). In conclusion, the pattern of ISR in most DES-ISR in this unselected patient population was focal, with higher rates of diffuse intrastent restenosis seen with PES-ISR. Treatment with either repeated DES implantation or balloon angioplasty for DES-ISR was safe and associated with low overall rates of target-lesion revascularization and major adverse cardiac events at 1 year.

Treatment of drug-eluting stent restenosis with the same versus different drug-eluting stent

OBJECTIVE

The authors aimed to compare the clinical outcomes with repeat drug-eluting stent (DES) implantation utilizing the same type versus an alternate DES type for in-stent restenosis (ISR) of DES.

BACKGROUND

: DES are proven as an effective treatment for bare metal ISR.

METHODS

A cohort of 116 patients previously treated with a sirolimus-eluting stent (SES) or a paclitaxel-eluting stent (PES) who presented with angiographic ISR were treated with repeat DES. Of these, 62 (53.4%) were treated with different DES and 54 (46.6%) were treated with the same DES. This cohort was followed for clinical events at 30 days, 6 months, and 1 year.

RESULTS

Baseline characteristics were similar except for more diabetes among patients receiving the different type of DES. Of the 116, overall 16.4% of the DES were implanted for previous ISR and 2.6% had previously received brachytherapy. At 6 months, the overall target vessel revascularization (TVR) rate was 12.2% for the entire cohort. The TVR-major adverse cardiac event (MACE) rate for the patients treated with different DES was 14.5% and 16.7% for the same DES (P = 0.750). Overall TVR rate at 1 year was 28.8%. The TVR-MACE was 32.6% for different DES and 35.0% for the same DES (P = 0.814).

CONCLUSIONS

Reimplantation of DES for the treatment of DES ISR (same or different) is safe but associated with a high rate of recurrences at 1 year regardless of the initial DES type. Other treatment modalities for ISR of DES should be considered to further improve the overall TVR-MACE.