Vascular Brachytherapy for 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.

Coronary intravascular brachytherapy for in-stent restenosis: A review of the contemporary literature

Intracoronary stent restenosis (ISR) is a clinically relevant challenge in the modern era. Heterogeneity in patient- and lesion-specific factors can further compound this clinical challenge. Coronary intravascular brachytherapy (IVBT) was the standard therapeutic approach for ISR prior to the advent of drug-eluting stents (DES). Despite prospective data describing the superiority of DES over IVBT for treating de novo ISR, IVBT remains a treatment option for patients with complex disease. The purpose of this review is to evaluate the historical and contemporary literature surrounding IVBT in order to elucidate its role in modern cardiac care and to describe opportunities for future investigations to improve patient selection. Herein, we provide a review of the contemporary literature describing IVBT as a safe and effective treatment option for patients with recurrent, refractory ISR after multilayer DES and no good surgical or mechanical option. Combination therapy with emerging technologies such as DCBs may further increase efficacy.

Usefulness of Intracoronary Brachytherapy for Patients With Resistant Drug-Eluting Stent Restenosis

In-stent restenosis (ISR) remains a concern even in the drug-eluting stent (DES) era and carries a high risk of recurrence. Brachytherapy is being used as an alternative treatment for resistant ISR, yet the safety and efficacy of this approach has not been well studied. We analyzed the outcomes of 101 patients who underwent coronary brachytherapy for resistant DES ISR. Baseline demographic, clinical, procedural, and outcome data were collected by phone and from electronic records. Comorbidities and overt cardiovascular disease were highly prevalent. Median previous stent layers were 2 with a maximum of 5 layers. Procedural angiographic success rate was 97% and median time to discharge was 1 day after brachytherapy. The primary outcome of target vessel revascularization was 24% at 1 year, 32% at 2 years, and 42% at 3 years. The rate of nonfatal myocardial infarction was 0% at 1 year, 3.5% at 2 years, and 6% at 3 years. The rate of all-cause mortality was 8.5% at 1 year, 12% at 2 years, and 16% at 3 years. We observed only 1 case of late stent thrombosis. After multivariable adjustment, female gender (hazard ratio 2.37, 95% confidence interval 1.02 to 5.52, p = 0.04) and diffuse ISR pattern (hazard ratio 2.95, 95% confidence interval 1.21 to 7.17, p = 0.01) were independently associated with the primary outcome. In conclusion, brachytherapy is feasible for the treatment of resistant DES ISR and is associated with high immediate procedural success and reasonable efficacy in a complex patient population. This approach might be used as an alternative for these patients.

Vascular brachytherapy versus drug-eluting stents in the treatment of in-stent restenosis: A meta-analysis of long-term outcomes

INTRODUCTION

Clinical trials have shown a short-term benefit of drug-eluting stents (DES) compared to vascular brachytherapy (VBT) for treatment of in-stent restenosis (ISR). The long-term benefits of DES vs. VBT are conflicting in the literature. This study aimed to do a meta-analysis of long-term outcomes of DES compared to VBT for treatment of ISR.

METHODS

PubMed, EMBASE, Cochrane Central and unpublished data were searched for cohort studies and randomized controlled trials (RCTs) that directly compared VBT to DES for the treatment of ISR. We evaluated the following outcomes at 2-5 years of follow-up: target lesion revascularization (TLR), target vessel revascularization (TVR), myocardial infarction (MI), stent thrombosis, cardiovascular (CV) mortality, and overall mortality. Heterogeneity was defined as I(2) values > 25%. Review Manager 5.1 was used for statistical analysis.

RESULTS

We included 1,375 patients from five studies, of which three were RCTs. VBT was used to treat ISR in 685 (49.8%) patients. After a 2-5 year follow-up, no significant differences were found between treatment groups regarding MI (P = 0.49), stent thrombosis (P = 0.86), CV mortality (P = 0.35), and overall mortality (P = 0.71). TLR (OR 2.37; CI 1.55-3.63; P < 0.001) and TVR (OR 2.23; CI 1.01-4.94; P = 0.05) were significantly increased in patients who received VBT.

CONCLUSION

This study suggests that DES are associated with decreased long-term revascularization procedures when compared to VBT for the treatment of ISR. This benefit does not appear to be associated with a significant reduction in mortality or myocardial infarction.

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.

Late results (>10 years) of intracoronary beta brachytherapy for diffuse in-stent restenosis

INTRODUCTION

Until the development of drug-eluting stents (DES), diffuse in-stent restenosis (ISR) was the main limitation of bare-metal stents in percutaneous coronary intervention (PCI). Among the different treatments available, intracoronary brachytherapy (BT) emerged as one of the most promising, although it was almost abandoned with the increasing use of DES.

OBJECTIVE

To assess the Portuguese experience with 90Sr/90Y beta brachytherapy for the treatment of diffuse ISR regarding long-term (>10 years) major adverse cardiac events (MACE) and angiographic restenosis.

METHODS

This single-center, retrospective, observational study included 12 consecutive patients treated between January and June 2001, mean age 58.6±9.9 years (range 43-77 years), 11 male. All had chronic stable angina, 75% had dyslipidemia, 58% had hypertension, 50% had peripheral arterial disease, 42% had diabetes and 50% had multivessel disease. Recurrent ISR was present in half of the patients and 11 had normal left ventricular function. After balloon dilatation, BT was performed using an Sr90/Y90 (Novoste Beta-CathTM) beta radiation source. All patients remained under dual antiplatelet therapy until scheduled nine-month follow-up angiography. Patients were followed for the occurrence of death (all-cause and cardiovascular), non-fatal myocardial infarction (MI), revascularization, stent thrombosis and angiographic restenosis. MACE were defined as the combined incidence of cardiac death, MI and urgent target vessel revascularization.

RESULTS

In all cases there was both clinical and angiographic success. In a mean follow-up of 10.9±2.5 years, 19 events occurred in seven patients: death in three (25%), only one cardiac (8.3%); ST-elevation MI in one (related to a non-target vessel) (8.3%); and 15 revascularizations in five (42%), of which nine were of the target vessel (mainly in the first two years). There was only one case of probable stent thrombosis. Angiographic restenosis at nine months was 27% (three out of 11 patients), of which two were total occlusions. Ten-year MACE-free survival was 42% (5 patients).

CONCLUSIONS

Intracoronary beta brachytherapy for the treatment of diffuse ISR in this small cohort of patients proved to be safe and efficacious, with no late adverse events related to intracoronary radiation.

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.

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.

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.