Northwell intracoronary brachytherapy for the treatment of recurrent drug eluting stent in-stent restenosis (NITDI study group)

Outcomes of Intracoronary Brachytherapy for In-Stent Restenosis

Because of limited alternative options, intracoronary brachytherapy (ICBT) continues to be used for treating in-stent restenosis (ISR). We examined the indications, characteristics, and outcomes of ICBT in consecutive patients who underwent ICBT for ISR between January 2014 and December 2023 at a tertiary care center. During the study period 343 patients underwent ICBT of 502 lesions. The median patient age was 67 [60, 74] years, 73.4% of the patients were men, 77.3% had prior myocardial infarction, and 49.4% had prior coronary artery bypass graft surgery. The most common target vessel was the right coronary artery (38.7%) and 7.37% of lesions were in bypass grafts (33 saphenous vein grafts, 4 arterial grafts). A diffuse ISR pattern was found in 76.2% of lesions. Among the study lesions, 58.0% had 2 stent layers and 20.6% had 3 or more stent layers. Technical success was achieved in 96.1% of lesions. Follow-up was available for all patients with a mean follow-up of 701.5 days. The 3-year incidence of target lesion failure (TLF), target vessel myocardial infarction, and major adverse cardiac events were 36.4%, 17.2%, and 45.6%, respectively. In multivariable analysis, higher brachytherapy radiation dose was associated with a lower risk for TLF (aHR per 10 Gy: 0.73; 95% CI 0.54-0.93; p = 0.048). Repeat ICBT procedures had a higher incidence of TLF over 3 years compared with lesions treated with ICBT for the first time (log-rank test: p = 0.008). In conclusion, the 3-year incidence of TLF after ICBT is 36.4% and was lower with higher radiation dose and higher in lesions retreated with ICBT.

Recurrent drug eluting stent, in-stent restenosis (DES-ISR): Epidemiology, pathophysiology & treatment

Coronary artery in-stent restenosis (ISR) is driven by neointimal hyperplasia and neo-atherosclerosis in previously placed stents. Drug eluting stents (DES) have been adopted as first line therapy for the initial episode of ISR. However, recurrent ISR has limited durable salvage options. In this article we review the pathophysiology, incidence, and management options of recurrent DES- ISR.

Complications of intravascular brachytherapy

INTRODUCTION

There is some evidence of a dose-response relationship for intravascular brachytherapy (IVBT) of native vessel or first-time in-stent restenosis (ISR). It has also been shown that in-field failure predominates following intravascular brachytherapy-treated lesions. Accordingly, it may be advantageous to increase the radiation dose(s) currently used. Given the rationale for escalation from currently doses, a scrutiny of the potential complications that have been reported seems timely.

METHODS

PubMed was searched from 1966 through November 21st, 2023, using the terms coronary and brachytherapy, yielding 1287 references. A 10/16/24 follow-up search of Embase, using the terms "coronary and brachytherapy and complications", yielding 511 articles. In total, 68 articles were identified as adverse event reports based on their title, or by scrutinizing articles that did not mention adverse events in their titles.

RESULTS

The best documented adverse IVBT-related event is the occurrence of late (> 1 month) thrombosis. Following identification of the risk, longer DAPT regimens were adopted, bringing the incidence to non-IVBT levels. A variety of other adverse events have been reported, including aneurysms, dissections, arterial spasm, "black holes" and vasomotor response inhibition. However, none of which were associated with adverse clinical outcomes.

CONCLUSIONS

Nearly all reports regarding IVBT-related complications are retrospective analyses of a limited number of events, subject to reporting bias. Clinically important IVBT-related complications, at current doses, appear highly unlikely.

Extreme coronary radiation doses from intravascular brachytherapy

PURPOSE

To evaluate coronary artery integrity after very high radiation doses from intravascular brachytherapy (IVBT) in the setting of source asymmetry.

METHODS

Ten patients treated for right coronary artery (RCA) in-stent restenosis (ISR) between 2017 and 2021 and for whom follow-up angiograms were available were identified from departmental records. Procedural angiograms, taken to document source position, were used to estimate vascular wall doses. The 2.5 mm proximal source marker was used to estimate the distance from source center to the media and adventitia. Distances were converted to dose (Gy) using the manufacturers' dose fall-off table, measured in water. Follow-up films were scrutinized for any sign of late vascular damage.

RESULTS

The average minimal distance from catheter center to the adjacent media and the adventitia was 0.9 mm (±0.2) mm and 1.4 mm (±0.2), respectively. The average maximum media and adventitial doses adjacent to the source were 75 Gy (±26) and 39 Gy (±14), respectively. Follow-up angiograms were available from 0.6 years to 3.9 years following IVBT (median: 1.6 years). No IVBT-treated vascular segment showed signs of degeneration, dissection or aneurysm.

CONCLUSION

IVBT vascular wall doses are frequently far higher than prescribed. The lack of complications in this unselected group of patients gives a modicum of reassurance that raising the prescription dose is unlikely to lead to a sudden appearance of complications.

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.

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.

"Back to the future: Beta radiation to treat recurrent in-stent restenosis"

When a patient presents with restenosis and two layers of previously place drug eluting stents this is a true treatment dilemma for the interventionist. Beta radiation has proven its efficacy to decrease in-stent restenosis compared to standard PCI. No drug-coated balloons are currently available in the United States for treatment of in-stent restenosis.

Intracoronary brachytherapy for the treatment of recurrent drug-eluting stent in-stent restenosis: A systematic review and meta-analysis

BACKGROUND

We performed a meta-analysis on observational studies since randomized control trials are not available. We studied intracoronary brachytherapy (ICBT) and recurrent drug eluting stent in-stent restenosis (DES-ISR) to evaluate the procedural success, target lesion revascularization (TLR), incidence of myocardial infarction (MI) and all-cause mortality at 2 years follow-up.

AIM

To perform meta-analysis for patients undergoing ICBT for recurrent DES-ISR.

METHODS

We performed a systematic search of the PubMed/MEDLINE, Cochrane and DARE databases to identify relevant articles. Studies were excluded if intra-coronary brachytherapy was used as a treatment modality for initial ISR and studies with bare metal stents. We used a random-effect model with DerSimonian & Laird method to calculate summary estimates. Heterogeneity was assessed using I² statistics.

RESULTS

A total of 6 observational studies were included in the final analysis. Procedural angiographic success following intra-coronary brachytherapy was 99.8%. Incidence of MI at 1-year was 2% and 4.1% at 2-years, respectively. The incidence of TLR 14.1% at 1-year and 22.7% at 2-years, respectively. All-cause mortality at 1- and 2-year follow-up was 3% and 7.5%, respectively.

CONCLUSION

Given the observational nature of the studies included in the analysis, heterogeneity was significantly higher for outcomes. While there are no randomized controlled trials or definitive guidelines available for recurrent ISR associated with DES, this analysis suggests that brachytherapy might be the alternative approach for recurrent DES-ISR. Randomized controlled trials are required to confirm results from this study.