Effectiveness of sirolimus-eluting stent implantation for treatment of in-stent restenosis after brachytherapy failure

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.

Update on drug-eluting coronary stents

The introduction of drug-eluting stents (DES) to interventional cardiology practice has resulted in a significant improvement in the long-term efficacy of percutaneous coronary interventions. DES successfully combine mechanical benefits of bare-metal stents and stabilizing the lumen, with direct delivery and the controlled elution of a pharmacologic agent to the injured vessel wall to suppress further neointimal proliferation. The dramatic reduction in restenosis has resulted in the implementation of DES in clinical practice, and has rapidly expanded the whole spectrum of successfully treatable coronary conditions, particularly in high-risk patients and complex lesions. In this review the authors present current data on DES. Currently, two types of DES are available in the USA: sirolimus-eluting stents (SES) CYPHER (Cordis Corp., FL, USA) and paclitaxel-eluting stents (PES) TAXUS (Boston Scientific, MA, USA), and many more are on the way to approval. In addition to sirolimus and paclitaxel, several other drugs have been successfully used in DES. Everolimus and ABT-578 are both analogs of sirolimus that also have immunosuppressive and antiproliferative properties. Another approach in the development of DES is to use drugs that can accelerate re-endothelialization and restore normal endothelial function following vascular injury. Recent advances in vascular gene transfer have also demonstrated potential new treatment modalities for cardiovascular disease, particularly in the treatment of vascular restenosis.

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.

Combining sirolimus-eluting stents and external irradiation in cholesterol-fed rabbits increased incomplete stent apposition and decreased re-endothelialization

Restenosis after the implantation of a drug-eluting stent or after vascular irradiation therapy shares similar physiopathological mechanisms. No experimental data are currently available on vascular wall behavior after external irradiation on arteries stented with sirolimus-eluting stents (SES). Ten New Zealand white rabbits received a 0.5% cholesterol-enriched chow for 1 month. Bilateral iliac artery stent implantation was then performed with an SES (Cypher; Cordis Corp). The animals were randomized into either an irradiated group (I, 2 Gy external x-ray irradiation, n = 5) or a control group (C, n = 5). The cholesterol-enriched chow was continued for 1 additional month after stent implantation. The stented arteries were harvested for histological analyses. The number and the percentage of incompletely apposed stents struts (IASS) were significantly higher in irradiated versus control group (3.05 +/- 0.46 vs. 1.57 +/- 0.27 IASS, P < 0.01, and 28.44% +/- 3.97% vs. 15.2% +/- 2.46% of IASS, P < 0.01, respectively). The mean neointimal thickness behind the IASS was also higher in the irradiated group (I: 28.3 +/- 2.5 microm vs. C: 18.2 +/- 2.3 microm, P < 0.01). Re-endothelialization was lower in irradiated group (I: 44.6% +/- 17.5% vs. C: 75.2% +/- 5.7%, P < 0.01). The present study revealed that low-dose external irradiation increased incomplete stent apposition and reduced re-endothelialization of SES. These results underscore the potential deleterious cumulative side effects of these 2 procedures to prevent restenosis.

A pyrrole-imidazole polyamide targeting transforming growth factor-beta1 inhibits restenosis and preserves endothelialization in the injured artery

AIMS

Although the use of drug-eluting stents (DESs) has been shown to limit neointima hyperplasia, currently available DESs may adversely affect re-endothelialization. To evaluate whether a novel gene silencer pyrrole-imidazole (PI) polyamide targeting transforming growth factor (TGF)-beta1 is a candidate agent for the DESs, we examined the effects of PI polyamide targeting the TGF-beta1 promoter on neointimal formation in rat carotid artery after balloon injury.

METHODS AND RESULTS

PI polyamide was designed to span the boundary of the AP-1 binding site of the TGF-beta1 promoter. After inducing balloon injury to arteries, incubation with PI polyamide was carried out for 10 min. Neointimal thickening and re-endothelialization were evaluated at 21 days after injury. Fluoresceinisothiocyanate-labelled PI polyamide was distributed into most of the nuclei in the injured artery without any delivery reagents. PI polyamide (100 microg) significantly inhibited neointimal thickening at 21 days after injury by 57%. PI polyamide targeting TGF-beta1 significantly decreased the expression of TGF-beta1 mRNA and protein in the artery at 3 days after injury and also suppressed the expression of connective tissue growth factor (CTGF), fibronectin, collagen type 1, and lectin-like ox-LDL receptor-1 mRNAs. A morphometric analysis showed that PI polyamide targeting TGF-beta1 accelerated re-endothelialization in the injured artery.

CONCLUSION

These findings suggest that the synthetic PI polyamide targeting the TGF-beta1 promoter may have the potential to suppress neointimal hyperplasia after arterial injury by the down-regulation of TGF-beta1 and CTGF and the reduction of the extracellular matrix. As a result, PI polyamide targeting TGF-beta1 may therefore be a potentially effective agent for the treatment of in-stent restenosis, as a candidate agent for the next-generation DES.

Novel Gene Silencer Pyrrole-Imidazole Polyamide Targeting Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 Attenuates Restenosis of the Artery After Injury

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a membrane protein that can support the binding, internalization, and proteolytic degradation of oxidized low-density lipoprotein. The LOX-1 expression increases in the neointima after balloon injury. To develop an efficient compound to inhibit LOX-1, we designed and synthesized a novel gene silencer pyrrole-imidazole (PI) polyamide targeting the rat LOX-1 gene promoter (PI polyamide to LOX-1) to the activator protein-1 binding site. We examined the effects of PI polyamide to LOX-1 on the LOX-1 promoter activity, the expression of LOX-1 mRNA and protein, and neointimal hyperplasia of the rat carotid artery after balloon injury. PI polyamide to LOX-1 significantly inhibited the rat LOX-1 promoter activity and decreased the expression of LOX-1 mRNA and protein. After balloon injury of the arteries, PI polyamide to LOX-1 was incubated for 10 minutes. Fluorescein isothiocyanate–labeled PI polyamide was distributed to almost all of the nuclei in the injured artery. PI polyamide to LOX-1 (100 μg) significantly inhibited the neointimal thickening by 58%. PI polyamide preserved the re-endothelialization in the injured artery. PI polyamide significantly inhibited the expression of LOX-1, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and matrix metalloproteinase-9 mRNAs in the injured artery. The synthetic PI polyamide to LOX-1 decreased the expression of LOX-1 and inhibited neointimal hyperplasia after arterial injury. This novel gene silencer PI polyamide to LOX-1 is, therefore, considered to be a feasible agent for the treatment of in-stent restenosis.

Use of sirolimus-eluting stents for treatment of in-stent restenosis: long-term follow-up

OBJECTIVES

The aims of this study were to assess (i) the feasibility, safety and efficacy of sirolimus-eluting stents (SESs) in treating in-stent restenosis (ISR), (ii) the risk factors for recurrent ISR, and (iii) the long-term major adverse cardiac events (MACE).

METHODS

Between May 2002 and April 2004, 100 consecutive patients with evidence of myocardial ischaemia and 112 ISRs in native coronary arteries were treated using SESs. We evaluated the rate of procedural and clinical success, the incidence of in-hospital and long-term MACE, the recurrence rate of ISR after 6-8 months, and the risk factors for recurrent ISR and follow-up MACE.

RESULTS

Forty-five percent of the lesions were directly stented. After stent implantation, the minimal lumen diameter increased from 0.51 +/- 0.32 to 2.50 +/- 0.32 mm in the stents and to 2.30 +/- 0.35 mm in the lesions (acute gain 1.99 +/- 0.37 mm). The procedural success rate was 99%. The clinical success rate was 88%. MACE occurred in 2.0% of patients during hospitalisation and in 12.8% after a median follow-up of 15.1 months (interquartile range 8.4-19.7). The recurrence rate of ISR was 11.8% after a median follow-up of 7.7 months (interquartile range 7.4-8.4). The risk for recurrent ISR was significantly higher in patients with diabetes or hypertension, in those aged more than 65 years and in female patients, as well as in the lesions with a small minimal lumen diameter. Three-vessel disease and age were risk factors for MACE.

CONCLUSIONS

This study confirms the feasibility, safety and effectiveness of using SESs to treat ISR, and identifies a risk profile for recurrent ISR and MACE.

Stent-based delivery of antisense oligodeoxynucleotides targeted to the PDGF A-chain decreases in-stent restenosis of the coronary artery

BACKGROUND

Although the use of drug-eluting stents (DESs) has been shown to limit neointima hyperplasia, currently available DESs may adversely affect reendothelialization, possibly precipitating cardiac events. We evaluated the effect of an antisense oligodeoxynucleotide (ODN) targeted to the platelet-derived growth factor (PDGF) A-chain on in-stent restenosis in pig coronary artery.

METHODS

A bare metal stent coated with phosphorothioate-linked antisense ODN or nonsense ODN, or a bare metal stent without ODN (control), was implanted in the mid segment of the left anterior descending artery (LAD). Twenty-eight days after implantation, angiography and intravascular ultrasound (IVUS) were performed, the LAD was removed, and stenosis was evaluated pathologically.

RESULTS

Volumetric stenosis ratios were 64 +/- 11.9, 44 +/- 3.4, and 26 +/- 3.8% in coronary arteries implanted with control, nonsense ODN-coated, and antisense ODN-coated stents, respectively. In angioscopic findings, the lumen surface was smooth in the stented segments in all groups. Struts of antisense ODN-coated stents were observed embedded in the neointima, whereas embedding was not observed in nonsense ODN-coated stents or control stents, indicating a decrease in hyperplasia in response to antisense ODN treatment. Pathologic findings showed 77 +/- 5.8, 68 +/- 12.2, and 38 +/- 5.3% stenosis in coronary arteries implanted with control stents, nonsense ODN-coated stents, and antisense ODN-coated stents, respectively. A continuous lining of endothelial cells was observed along the lumen of coronary arteries implanted with antisense ODN-coated stents.

CONCLUSIONS

Stent-based delivery of an antisense ODN targeted to the PDGF A-chain effectively inhibits neointima formation after stent implantation in pig coronary artery by suppressing VSMC hyperplasia and preserving endothelialization. Antisense-ODNs may provide a therapy for in-stent restenosis of the coronary artery.

Repeat intracoronary beta-brachytherapy using a rhenium-188-filled balloon catheter for recurrent restenosis in patients who failed intracoronary radiation therapy

BACKGROUND

Conventional percutaneous coronary intervention (PCI) in restenotic lesions after brachytherapy failure is associated with a high recurrence rate of restenoses and revascularizations. Intracoronary brachytherapy using a liquid rhenium-188-filled balloon in de novo or restenotic lesions safely and effectively reduced restenosis rates. We report clinical and angiographic data regarding the safety and efficacy of rhenium-188 brachytherapy in restenoses after brachytherapy failure.

METHODS

Fourteen patients with restenosis after brachytherapy failure received rhenium-188 beta-brachytherapy. Follow-up was performed angiographically after 6 months and clinically after 12 months. Primary clinical endpoint was the incidence of major adverse cardiac events (MACE) defined as any death, myocardial infarction or repeat revascularization in the target vessel within 12 months. Secondary angiographic endpoints were the binary restenosis rate and late loss in the total segment including edge effects at 6 months.

RESULTS

The prescribed dose of 22.5 Gy (n=12) or 30 Gy (n=2) was successfully delivered in all patients. In two lesions, a bare-metal stent was implanted. The mean length of the irradiated segment was 40.0+/-15.7 mm. The mean diameter of the irradiation balloon was 2.96+/-0.37 mm. Angiographic follow-up was done in 13 of 14 patients. There was no edge stenosis or coronary aneurysm. Within the total segment, late loss was 0.39+/-0.64 mm and late loss index was 0.18+/-0.40 with a binary restenosis rate of 23%. Twelve months' clinical follow-up was available in all patients, which showed a MACE rate of 7% due to one target lesion revascularization (TLR).

CONCLUSIONS

Intracoronary beta-brachytherapy with a liquid rhenium-188-filled balloon in restenoses after intracoronary radiation therapy failure including 12 months combined antiplatelet therapy is safe with respect to vessel thrombosis, late coronary occlusion or aneurysm formation. With limited use of stenting, angiographic and clinical follow-up for repeat brachytherapy were favorable and it is associated with low restenosis and target vessel revascularization rate.

Three-year follow-up after intracoronary beta-radiation therapy for in-stent restenosis

BACKGROUND

Most studies that proved intracoronary radiation therapy (IRT) to be highly effective to reduce recurrent restenosis after treatment of in-stent restenosis (ISR) have looked at time periods up to 12 months. Whether the beneficial effect from radiation is sustained during long-term follow-up remains a concern. This study sought to evaluate the effectiveness of IRT using a beta-emitter during a 3-year follow-up period.

METHODS

One hundred twenty-eight consecutive symptomatic patients (mean age, 63 +/- 11 years) with 134 in-stent restenotic lesions were treated for ISR with IRT (noncentred beta-emitter, Novoste; radiation dosis 21.1 +/- 3.1 Gy). Six-month angiographic follow-up was obtained in 104 patients (81%) with 105 lesions (78%). All patients underwent 36-month clinical follow-up.

RESULTS

Six-month angiographic restenosis rate was 22% in stent (29% in lesion) with an in-stent late loss of 0.49 +/- 0.62 mm. Target lesion resvascularization (TLR) at 6-month follow-up was performed in 23 cases (18%). MACE (death, myocardial infarction, and target vessel revascularisation) was observed in 24 patients (19%). At 36-month follow-up, TLR increased to 36 cases (28%) and MACE was observed in 47 patients (37%). In a multivariate analysis, minimal lumen diameter before treatment of ISR using IRT was the only predictor of recurrent TLR at 36 months (OR = 0.131; 95% CI, 0.068-0.254; p = 0.002). In a subgroup of patients (N = 15) without restenosis at 6-month angiography but with clinically driven recurrent late angiography (mean, 18 +/- 7 months); in-lesion late loss increased from 0.47 +/- 0.54 mm at 6 months to 1.27 +/- 0.76 mm at repeated angiography (p = 0.005).

CONCLUSION

There is a considerable number of delayed recurrent restenosis post IRT for ISR. This is due to ongoing late loss more than 6-month post IRT. The minimal lumen diameter before IRT predicts the need for recurrent TLR at 36 months.

Brachytherapy with gamma radiation of a coronary artery for in-stent restenosis may induce the regression of in-stent restenosis of an adjacent coronary artery without angioplasty. First case report and review of the literature

Here, we present a case of a 63-year-old male who presented with in-stent restenosis of two coronary arteries simultaneously (mid circumflex and proximal ramus). After the brachytherapy of the circumflex artery for in-stent restenosis, the patient refused the staged procedure for the ramus in-stent restenosis. After approximately 2 years, the patient underwent coronary angiography for recurrent chest pain. Surprisingly, the proximal ramus stent showed marked regression of in-stent restenosis. We hypothesized that the gamma brachytherapy of the circumflex artery could have induced the regression of in-stent restenosis of the adjacent ramus artery due to the deep tissue penetration of gamma radiation. Based on our observation, we believe that in the treatment of in-stent restenosis of a coronary artery, the initial balloon angioplasty may not be as important as the radiation itself. This observation warrants further study to evaluate the effect of external or internal radiation on in-stent restenosis without balloon angioplasty. If our hypothesis is confirmed, the treatment of in-stent restenosis with external radiation could substantially simplify the treatment of this disease. This case report follows a brief review of the literature.

Contemporary Stent Treatment of Coronary Bifurcations

Treatment of coronary bifurcation lesions represents a challenging area in interventional cardiology. The introduction of drug-eluting stents (DES) reduced restenosis in the main branch (MB). However, restenosis at the ostium of the side branch (SB) remains a problem. Although stenting the MB with provisional SB stenting seems to be the prevailing approach, in the era of DES various two-stent techniques emerged (crush) or were re-introduced (V or simultaneous kissing stents, crush, T, culottes, Y, skirt) to allow stenting in the SB when needed. This review describes in detail various techniques used for implantation of two stents by intention to treat.

Drug-eluting stents for the treatment of in-stent restenosis

Treatment of in-stent restenosis (ISR) remains problematic despite the widespread application of drug-eluting stents (DES). Challenging lesion cohorts such as diffuse ISR and restenosis after failed intracoronary radiation therapy (IRT) maybe best treated with DES. The overall benefit of DES appears inferior to their utility in treating de novo coronary lesions. Randomised trials comparing DES and IRT will soon be available to determine the optimal therapy for ISR. The challenge to treat ISR in the DES era is the next frontier of interventional cardiology.