Coronary Intravascular Brachytherapy for Recurrent Coronary Drug-Eluting Stent In-Stent Restenosis: A Systematic Review and Meta-Analysis

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.

Intracoronary Brachytherapy for Drug-Eluting Stent Restenosis: Outcomes and Clinical Correlates

Background

This study aimed to report outcomes of intracoronary brachytherapy (ICBT) in treating drug-eluting stent (DES) in-stent restenosis (ISR) and identify correlated factors.

Methods

Patients who underwent ICBT for DES ISR from 2010 to 2021 were included in this single-institution retrospective PCI registry. Patients were treated with balloon angioplasty, laser atherectomy, and/or rotational atherectomy, followed by ICBT at a dose of 18.4-25 Gy delivered at the site of ISR with dose determined by the reference vessel size. The primary outcome was 3-year target lesion failure rate (TLF). Secondary end points were 1-year TLF, target lesion revascularization (TLR), all-cause mortality, and cardiac mortality.

Results

In total, 330 consecutive patients presented with 345 treated lesions; 70% were male, age was 66 ± 11 years, 55% were diabetic patients, 62% underwent previous bypass surgery, and 89% were placed with at least 2 stent layers at the treated site. The rate of TLF was 18% at 1 year and 46% at 3 years. All-cause mortality and cardiac mortality rates were 19.8% and 12.3% at 3 years. The number of stent layers was associated with 3-year TLF (1 layer, 33.3%; 2 layers, 47.0%, >3 layers, 60.2%; P = .045). Diabetes, repeat ICBT, final percent stenosis, lesion length, and intravascular imaging use were not correlated with the primary outcome. Lower ICBT dose (P = .035) and restenosis <1 year from previous percutaneous coronary intervention (P = .044) were correlated with early (1-year) TLF.

Conclusion

ICBT for recurrent DES ISR provided low recurrence rates at 1 year, which increased substantially by 3 years. Outcomes were most closely correlated with the number of stent layers, but early restenosis and lower ICBT dose adversely affected early TLF.

Utilization of Non-Drug-Eluting Devices for Inpatient Percutaneous Coronary Intervention in the United States

There is a paucity of data on the contemporary use of non-drug-eluting devices (balloon angioplasty or bare-metal stents) in contemporary percutaneous coronary intervention (PCI) in the United States. We utilized the Nationwide Readmissions Database to identify patients hospitalized to undergo PCI with non-drug-eluting devices from 2016 to 2019. The main outcome of interest was the trends in utilization over the study years. Among 1,870,262 PCI procedures, 127,810 (6.8%) were performed with non-drug-eluting devices; 72% of these were in the setting of acute myocardial infarction (MI). The use of non-drug-eluting devices decreased throughout the study period from 12.9% of all PCI in the first quarter of 2016 to 3.4% in the last quarter of 2019 (p <0.001). Factors associated with their use included advanced age and high bleeding risk. Only a small percentage were used as a bridge to coronary artery bypass graft surgery (2%) and for treatment of in-stent restenosis (3%). The in-hospital mortality was 5.8% for the entire cohort and 6.6% when the indication for use was an acute MI. In patients presenting with an acute MI, reinfarction within 30 days was common and occurred in 18% of the patients. In conclusion, the use of non-drug-eluting devices in PCI in the United States decreased from 2016 to 2019. Factors associated with their use included old age and high bleeding risk. Due to suboptimal outcomes in patients currently being treated with non-drug-eluting devices, there remains an unmet clinical need for alternative treatment options.

A State-of-the-Art Review: The Percutaneous Treatment of Highly Calcified Lesions

Coronary artery calcification is prevalent in coronary heart disease with its progression being predictive of future adverse cardiac events. Its presence is considered to be a marker of interventional procedural complexity. Several adjunctive percutaneous coronary intervention tools, such as modifying balloons, atherectomy devices and intravascular lithotripsy, now exist to successfully treat calcified lesions. In this state-of-the-art review, a step-wise progression of strategies is described to modify coronary plaque, from well-recognised techniques to techniques that should only be considered when standard manoeuvres have proven unsuccessful. Technology has advanced greatly over the past few decades and we discuss how future technologies might shape percutaneous intervention.

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.

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.

Stent detection with very thick tissue coverage in intravascular OCT

Coronary stenting or percutaneous coronary intervention (PCI) is widely used to treat coronary artery disease. Improper deployment of stents may lead to post-PCI complication, in-stent restenosis, stent fracture and stent thrombosis. Intravascular optical coherence tomography (OCT) with micron-scale resolution provides accurate in vivo assessment of stent apposition/malapposition and neointima coverage. However, manual stent analysis is labor intensive and time consuming. Existing automated methods with intravascular OCT mainly focused on stent struts with thin tissue coverage. We developed a deep learning method to automatically analyze stents with both thin (≤0.3mm) and very thick tissue coverage (>0.3mm), and an algorithm to accurately analyze stent area for vessels with multiple stents. 25203 images from 56 OCT pullbacks and 41 patients were analyzed. Three-fold cross-validation demonstrated that the algorithm achieved a precision of 0.932±0.009 and a sensitivity of 0.939±0.007 for stents with ≤0.3mm tissue coverage, and a precision of 0.856±0.019 and a sensitivity of 0.874±0.011 for stents with >0.3mm tissue coverage. The correlation between the automatically computed and manually measured stent area is 0.954 (p<0.0001) for vessels with a single stent, and is 0.918 (p<0.0001) for vessels implanted with multiple stents. The proposed method can accurately detect stent struts with very thick tissue coverage and analyze stent area in vessels implanted with multiple stents, and can effectively facilitate the evaluation of stent implantation and post-stent tissue coverage.

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.