Clinical outcomes for sirolimus-eluting stent implantation and vascular brachytherapy for the treatment of in-stent restenosis

High nitrogen stainless steel drug-eluting stent - Assessment of pharmacokinetics and preclinical safety in vivo

Pharmacokinetic analyses were performed using 20 pigs for 120-days implantation, while one sirolimus-eluting stent was implanted into one of their coronary artery. At different time points, the residual sirolimus on the stent, delivered locally (to artery wall), regionally (to adjacent and downstream muscle) and systemically (to plasma and visceral organs), was detected throughout 120 days. Preclinical safety evaluation was performed using 32 pigs for 180-days implantation to study the safety of metal platform material and the effectiveness of sirolimus eluting coating on the HNS stent. The neointima area, restenosis rate and inflammatory grade for HNS and control group stents were detected and analyzed. Approximately 80% sirolimus was eluted from the sirolimus-eluting stents after 30-days implantation in vivo. Additionally, there was sustained sirolimus in the artery wall, cardiac muscle and heart throughout 120-days implantation, and sirolimus accumulated to the peak at 90-days implantation. It was inferred that the sirolimus eluting stent in this study was covered by neointima before 90-days implantation, indicating that the sirolimus eluting coating on the HNS stent was safe and effective. Very little sirolimus was distributed in visceral organs after 14-days implantation. HNS sirolimus-eluting stent exhibited lower restenosis rate and lower inflammatory grade than control group, which verified that the sirolimus-eluting coating design in this study was reasonable and practical. In addition, there were no significant difference in restenosis rate and inflammatory score between HNS bare-metal stent and drug-eluting stents, illustrating that HNS has good bio-compatibility and is suitable to use as coronary artery stent material.

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First time to investigate the pharmacokinetics of drug eluting stents for 120 days, found the relationship between the pharmacokinetics and tissue response, which has been rarely reported.

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Verified that the drug-eluting stent made of high nitrogen stainless steel endothelialization finished after 90 days implantation, without endothelialization delay.

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HNS has been proved that it is a better biocompatibility and bio-safe metal platform material, owing better property to be used in clinic.

Everolimus-eluting versus paclitaxel-eluting stents for treatment of bare metal stent restenosis

First-generation drug-eluting stents have been proved to be very effective for the treatment of bare metal stent in-stent restenosis (BMS ISR). The efficacy of second-generation drug-eluting stents in this setting remains less well defined. The present study compared the long-term clinical outcome after treatment of BMS ISR using the second-generation everolimus-eluting stent (EES) to that after treatment using the paclitaxel-eluting stent (PES). A total of 174 patients with BMS ISR underwent percutaneous coronary intervention using a PES (95 patients) or an EES (79 patients) from 2003 to 2010. The patients in the PES and EES groups were followed up for 42.2 ± 22.2 and 18.3 ± 8.2 months, respectively. The primary end point of the study was survival free of major adverse cardiac events at 1 year. The secondary end points were survival free of the need for revascularization of the target lesion and definite stent thrombosis. The baseline clinical and angiographic parameters were comparable between the 2 groups. The freedom from major adverse cardiac event rate at 1 year of follow-up was 4.5% and 13.6% (p = 0.0663) for the EES and PES groups, respectively. The target lesion revascularization (TLR) rates were greater in the PES group at 1 year of follow-up compared to the EES group (1% vs 11.5%, p = 0.0193). The rate of myocardial infarction, death, and definite stent thrombosis for the EES and PES groups at 1 year of follow-up was 0% versus 4.2% (p = 0.0984), 3% versus 2.1% (p = 0.6855), and 0% versus 2.1% (p = 0.2382), respectively. The use of a PES for treatment of ISR was the only independent predictor of recurrent TLR at 1 year of follow-up (odds ratios 1.11, 95% confidence interval 1.05 to 1.18; p = 0.0193). During the complete follow-up period, the rates of TLR, myocardial infarction, death, major adverse cardiac events, and definite stent thrombosis were not different between the 2 treatment groups. In conclusion, EES resulted in reduced rates of TLR at 1 year of follow-up compared to PES when used for treatment of BMS ISR. However, at long-term follow-up, the event rates between EES and PES were comparable after treatment of BMS ISR.

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.

Preventing restenosis in early drug-eluting stent era: recent developments and future perspectives

Restenosis is the major limitation of the successful therapy of percutaneous coronary intervention (PCI) for patients with coronary artery disease. The problem was appreciated in the late 1970s to early 1980s. Only in recent years, anti-restenotic therapy has achieved a breakthrough with the development of drug-eluting stents. Here, we provide an overview about pathological mechanisms of restenosis after PCI. Present therapeutic approaches to overcome restenosis and recent clinical results are revisited, and some major concerns in the post-drug-eluting stent era are discussed.

3-year follow-up of the SISR (Sirolimus-Eluting Stents Versus Vascular Brachytherapy for In-Stent Restenosis) trial

OBJECTIVES

The aim of this study was to evaluate long-term outcome of patients treated for in-stent restenosis of bare-metal stents (BMS).

BACKGROUND

Treatment of restenosis of BMS is characterized by high recurrence rates. Vascular brachytherapy (VBT) improved outcome although late catch-up events were documented. Drug-eluting stents tested against VBT in this setting were found superior for at least the first year; superiority at longer follow-up is uncertain.

METHODS

We evaluated 3-year outcome of the multicenter SISR (Sirolimus-Eluting Stents Versus Vascular Brachytherapy for In-Stent Restenosis) trial, which randomized patients with restenosis of BMS to either a sirolimus-eluting stents (SES) or VBT.

RESULTS

Target vessel failure (cardiac death, infarction, or target vessel revascularization [TVR]) at 9 months as previously reported was significantly improved with SES. Kaplan-Meier analysis at 3 years documented that survival free from target lesion revascularization (TLR) and TVR continues to be significantly improved with SES: freedom from TLR 81.0% versus 71.6% (log-rank p = 0.018), and TVR 78.2% versus 68.8% (log-rank p = 0.022), SES versus VBT. At 3 years, target vessel failure and major adverse cardiac events (death, infarction, emergency coronary artery bypass grafting, or repeat TLR) remained improved with SES, but did not reach statistical significance. There was no statistically significant difference in definite or probable stent thrombosis (3.5% for SES, 2.4% for VBT; p = 0.758).

CONCLUSIONS

At 3 years of follow-up, after treatment of in-stent restenosis of BMS, patients treated with SES have improved survival free of TLR and TVR compared with patients treated with VBT. Stent thrombosis rates are not different between the 2 groups but are higher than reported in trials of treatment of de novo lesions.

A new wave in treatment of vascular occlusive disease: biodegradable stents--clinical experience and scientific principles

Stent-based therapies in percutaneous vascular intervention are associated with significant long-term complications related to in-stent restenosis. A growing body of literature demonstrates the feasibility of biodegradable materials for endovascular stents, which may, in theory, circumvent many of the immunologic and inflammatory response issues seen with long-term metallic stent failure in coronary and peripheral applications. This review describes the history of endovascular stents and the challenges encountered with metallic, drug-eluting, and biodegradable stents. A review of the basic engineering principles of biodegradable stents is provided, along with a discussion of the cellular mechanisms of restenosis.

Long-term follow-up of patients with sirolimus-eluting stents for treatment of bare-metal in-stent restenosis

BACKGROUND

Limited data is available on the long-term outcome after sirolimus-eluting stent (SES) implantation for in-stent restenosis.

METHODS

In 3 centers, consecutive patients (n=100) with percutaneous coronary intervention (PCI) for in-stent restenosis (n=110) were treated with SES: 28 lesions were focal, 40 diffuse, 17 proliferative, and 15 totally occluded (reference vessel diameter: 3.0+/-0.2 mm, lesion length: 13.8+/-5.7 mm).

RESULTS

SES implantation was successful in all patients. The mean follow-up was 50+/-12 months. The main univariate predictive factor of definite (4%) or probable (4%) SES thrombosis was revascularization without SES in a non-target site during the initial procedure (p<0.01). Repeated target lesion revascularization (TLR) was performed in 8 patients (8%) at 1 year, in 10 patients (10%) at 4 years. A cardiac event related to the SES occurred in 14 patients (14%) at one year, 17 patients (17%) at 4 years, and were associated with unstable angina (p<0.05), multivessel disease (p<0.02) and revascularization without SES in another site of the target vessel during the initial procedure (p<0.01).

CONCLUSIONS

SESs are effective at 4 years in the treatment of high risk patients with complex in-stent restenosis, with a low risk of TLR but a high risk of stent thrombosis. Most of cardiac events related to the target vessel occur during the first year, and are associated to a revascularization without SES in another site during the first procedure.

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.

Comparison of six-month angiographic and three-year outcomes after sirolimus-eluting stent implantation versus brachytherapy for bare metal in-stent restenosis

To evaluate long-term effectiveness of sirolimus-eluting stent (SES) implantation for diffuse bare metal in-stent restenosis (ISR), we compared 6-month angiographic and long-term (3-year) clinical outcomes of SES implantation and intracoronary brachytherapy (ICBT). SES implantation for diffuse ISR was performed in 120 consecutive patients and their results were compared with those from 240 patients treated with beta-radiation with balloons filled with rhenium-188 and mercaptoacetyltriglycine. The radiation dose was 15 or 18 Gy at a depth of 1.0 mm into the vessel wall. The primary end point was 3-year major adverse cardiac events including myocardial infarction, cardiac death, and target lesion revascularization. The 2 groups were similar in baseline clinical and angiographic characteristics. Lesion lengths were 25.1 +/- 14.2 mm in the SES group and 24.5 +/- 10.4 mm in the ICBT group (p = 0.15). In-stent acute gain was greater in the SES group than in the ICBT group (2.23 +/- 0.62 vs 1.91 +/- 0.54 mm, p <0.001). We obtained 6-month angiographic follow-up in 287 patients (79.7%). In-segment angiographic restenoses were 7.4% (7 of 94) in the SES group and 26.4% (51 of 193) in the ICBT group (p <0.05). Two myocardial infarctions (1 in each group) and 5 deaths (4 in SES group, 1 in ICBT group) occurred during 3-year follow-up. At 3 years, survival rates without target lesion revascularization (94.1 +/- 2.2% vs 84.6 +/- 2.3%, p = 0.011) and major adverse cardiac events (92.5 +/- 2.4% vs 84.2 +/- 2.4%, respectively, p = 0.03) were higher in the SES than in the ICBT group. In conclusion, compared with ICBT, SES implantation for diffuse ISR is more effective in decreasing recurrent restenosis and improving long-term outcomes.

Drug-eluting stent: a review and update

The development of stent has been a major advance in the treatment of obstructive coronary artery disease since the introduction of balloon angioplasty. However, neointimal hyperplasia occurring within the stent leading to in-stent restenosis is a main obstacle in the long-term success of percutaneous coronary intervention (PCI). The recent introduction of drug-eluting stents (DES) contributes a major breakthrough to interventional cardiology. Many large randomized clinical trials using DES have shown a remarkable reduction in angiographic restenosis and target vessel revascularization when compared with bare metal stents. The results of these trials also appear to be supported by evidence from everyday practice and noncontrolled clinical trials. However, the expanded applications of DES, especially in treating complex lesions such as left main trunk, bifurcation, saphenous vein graft lesions, or in-stent restenosis, are still under evaluation with ongoing studies. With the availability of different types of DES in the market, the issue of cost should not be a deterrent and DES will eventually be an economically viable option for all patients. The adoption of DES in all percutaneous coronary intervention may become a reality in the near future. In this review article, we summarize the recent development and progress of DES as well as compare and update the results of clinical trials.

Characterizing the spectrum of in-stent restenosis: implications for contemporary treatment

BACKGROUND

Reports addressing treatment of in-stent restenosis (ISR) are principally derived from clinical trials.

OBJECTIVES

To characterize the spectrum of ISR in an unselected population, and to explore clinical and angiographic factors determining management.

METHODS

During a prespecified six-month period before the introduction of drug-eluting stents, consecutive cases of ISR that were identified during clinically driven cardiac catheterization at five hospitals offering all approved treatment modalities for ISR were prospectively registered.

RESULTS

ISR was identified in 363 patients; 301 (84%) had one ISR lesion and 62 (16%) had multiple lesions. Unstable clinical presentations accounted for 51%, including 15% with ST-elevation myocardial infarction. The median interval (25th, 75th percentiles) from stent insertion to angiographic diagnosis of ISR was eight months (Q1,Q3: 4,15), with a median stented length of 18 mm (Q1,Q3: 15,28). The majority of lesions (60%) displayed a diffuse ISR pattern (Mehran types 2 and 3). ISR type was independent of time to re-presentation, diabetes, arterial territory and total stent length. Treatment included percutaneous coronary intervention (PCI) alone (n=139 [38%]), PCI with brachytherapy (n=105 [29%]), medical therapy (n=60 [17%]) and coronary artery bypass graft surgery (n=59 [16%]). Medical therapy was associated with small vessel size and recurrent ISR, and coronary artery bypass graft surgery was associated with multiple lesions, as well as diffuse, occlusive and recurrent ISR. For patients treated percutaneously, PCI treatment alone was more common for focal restenosis and after ST-elevation myocardial infarction, and brachytherapy was the more common treatment for diffuse and recurrent ISR, and stable angina.

CONCLUSIONS

These data provide a benchmark description of the spectrum of ISR with which the impact of drug-eluting stents may be compared and better understood.

Feasibility and safety of intra-coronary Beta irradiation with 144Ce/Pr for prevention of restenosis after percutaneous transluminal coronary angioplasty of in-stent restenotic lesions

BACKGROUND

Endovascular brachytherapy is a proven and efficacious treatment of coronary in-stent restenosis with established long-term benefit. Owing to its complexity and logistic inconveniences, brachytherapy did not find wide acceptance, especially in the current drug-eluting stents era. We conducted a single center, non-randomized pilot trial with 144Ce/Pr, utilizing a new high-energy Beta emitting source, for prevention of restenosis after percutaneous treatment of in-stent restenotic lesions.

METHODS AND RESULTS

Thirty consecutive patients presenting in-stent restenosis were enrolled in the study. After conventional balloon angioplasty, 144Ce/Pr was applied to the dilated coronary segment at a dose of 21Gy. Technical feasibility, safety and efficacy of 144Ce/Pr at 9 months clinical and angiographic follow-up were tested. Thirty-seven arterial segments were irradiated with 100% technical success and no in-hospital major adverse cardiac events (MACE). Five MACE were observed (13.5% of the treated segments) during 9 months follow-up, including four target lesion revascularizations and one episode of acute coronary syndrome secondary to sudden late thrombotic occlusion of the irradiated segment.

CONCLUSIONS

The study confirmed the safety and the feasibility of the intra-coronary Beta irradiation utilizing the 144Ce/Pr source. It also shows some practical advantages compared to traditional Gamma or other Beta sources. Considering the high-risk restenosis profile of the selected patients (i.e. diffuse in-stent restenosis, bifurcation lesions, small vessels) these results are encouraging in terms of restenosis prevention. Late acute thrombosis remains a problem requiring further improvement.

Comparison between drug-eluting stents and beta-radiation for the treatment of diffuse in-stent restenosis: clinical and angiographic outcomes

BACKGROUND

Initial reports on drug-eluting stents (DES) for the treatment for in-stent restenosis (ISR) show very good outcomes. Nevertheless, few data are available on direct comparison with intracoronary brachytherapy (IBT). The aim of this study was to compare brachytherapy and DES in treatment of diffuse ISR.

METHODS

One hundred forty-one consecutive patients with diffuse ISR were treated with IBT (68 patients; beta (90Sr/90Y) emitters) or with DES (73 patients; 32 with sirolimus-eluting and 41 with paclitaxel-eluting stents). Angiographic and clinical follow-up was scheduled within 9 months.

RESULTS

The first 74 lesions were treated with IBT (group 1) and the latter 74 with DES (group 2). The two groups were well matched for clinical/angiographic characteristics. At follow-up, restenosis rates were 37.8% (28/74) in IBT group and 14.9% (11/74) in DES group (P = .0028). A diffuse pattern of recurrence was more frequent after IBT (20/74 vs 6/74, P = .005). A worse outcome after IBT was associated with the "edge effect," accounting for most failures. Recurrence within the original restenotic stent was similar in both groups (12.9% vs 14.9% in groups 1 and 2 respectively, P = .8).

CONCLUSIONS

Drug-eluting stents are more effective than IBT with beta-irradiation in reducing recurrence rates after treatment of diffuse ISR. In case of failure, the pattern of restenosis is more benign after treatment with DES.

The role of radiation therapy in benign diseases

Although adequate prospective data are lacking, radiation therapy seems to be effective for many benign diseases and remains one of the treatment modalities in the armamentarium of medical professionals. Just as medication has potential adverse effects, and surgery has attendant morbidity, irradiation sometimes can be associated with acute and chronic sequelae. In selecting the mode of treatment, most radiation oncologists consider the particular problem to be addressed and the goal of therapy in the individual patient. It is the careful and judicial use of any therapy that identifies the professional. With an understanding of the current clinical data, treatment techniques, cost, and potential detriment, the goal is to provide long-term control of the disease while minimizing unnecessary treatment and potential risks of side effects. The art lies in balancing benefits against risks.

A randomized comparison of sirolimus-eluting stent with balloon angioplasty in patients with in-stent restenosis: results of the Restenosis Intrastent: Balloon Angioplasty Versus Elective Sirolimus-Eluting Stenting (RIBS-II) trial

OBJECTIVES

We sought to assess the effectiveness of sirolimus-eluting stents (SES) in patients with in-stent restenosis (ISR).

BACKGROUND

Treatment of patients with ISR remains a challenge.

METHODS

The Restenosis Intrastent: Balloon Angioplasty Versus Elective Sirolimus-Eluting Stenting (RIBS-II) study is a multicenter randomized trial conducted in 150 patients with ISR (76 allocated to SES and 74 to balloon angioplasty [BA]). The primary end point was recurrent restenosis rate at nine months. Secondary end points included prespecified subgroup analysis, lumen volume on intravascular ultrasound (IVUS), and a composite of major clinical events at one year.

RESULTS

Angiographic success was obtained in all patients. At 9-month angiographic follow-up (96% of eligible patients) minimal lumen diameter was larger (2.52 mm [interquartile range (IQR) 2.09 to 2.81] vs. 1.54 mm [IQR 0.91 to 2.05]; p < 0.001) and recurrent restenosis rate was lower (11% vs. 39%; p < 0.001) in the SES group. Prespecified subgroup analyses were consistent with the main outcome measure. Lumen volume on IVUS at 9 months was also larger (279 mm3 [IQR 227 to 300] vs. 197 mm3 [IQR 177 to 230]; p < 0.001) in the SES group. At one-year clinical follow-up (100% of patients), the event-free survival (freedom from death, myocardial infarction, and target vessel revascularization) was significantly improved in the SES group (88% vs. 69%; p < 0.004) as the result of a lower requirement for target vessel revascularization (11% vs. 30%; p < 0.003).

CONCLUSIONS

In patients with ISR, the use of SES provides superior long-term clinical, angiographic, and IVUS outcome than BA treatment.

Restenosis following implantation of bare metal coronary stents: pathophysiology and pathways involved in the vascular response to injury

This review summarizes the restenotic process that occurs after the implantation of bare metal coronary stents. The pathology of in-stent restenosis is distinct from that seen after balloon angioplasty and is characterized by neointimal proliferation and extracellular matrix deposition. The degree of neointimal proliferation is proportional to the amount of injury, the intensity of the inflammatory infiltrate and the association of stent struts with lipid-filled plaque. In-stent restenosis also appears to be associated with systemic markers of inflammation. Shear stress has an important influence on restenosis as does the presence and adhesiveness of vascular progenitor cells. Clinical predictors (e.g., artery size, stent length, diabetes, and gender) may affect the incidence of restenosis seen after stent placement. A number of catheter-based interventions have been used to treat in-stent restenosis. Although preliminary data suggest that the use of drug-eluting stents may be effective, only intracoronary radiation has shown consistent efficacy in randomized trials.

Predictive factors of cardiac events after implantation of sirolimus-eluting stents for treatment of in-stent restenosis

BACKGROUND

The factors associated with recurrent restenosis after SES implantation for in-stent restenosis are unknown. This study aimed to assess the clinical outcome and to analyse predictive factors of cardiac events in patients with in-stent restenosis treated with Sirolimus-eluting stent (SES).

METHODS

In 3 centers, consecutive patients (n = 100) with elective indication to percutaneous coronary intervention (PCI) for in-stent restenosis (n = 110) were treated with SES: 28 lesions were focal, 40 diffuse, 17 proliferative, and 15 showed total occlusion.

RESULTS

SES implantation was successful in all patients, without complication during the first hospital stay. The mean follow-up was 15 (10-24) months. A cardiac event related to the target vessel occurred in 24 (24%) patients, and was associated with dialysis status (p < 0.05), lower ejection fraction (p < 0.05) and revascularization without SES in another site (p < 0.0001). A cardiac event related to the SES occurred in 11 (11%) patients, secondary to an acute or sub-acute thrombosis of the SES (2%), to a late occlusion of the target vessel (4%) or to a non-occlusive restenosis of the SES (5%), and was associated with unstable angina (p < 0.01), multivessel disease (p < 0.03) and revascularization without SES in another site (p < 0.03). No cardiac event related to the SES occurred in patients with direct stenting. Target lesion revascularization for in-SES restenosis or occlusion of the target vessel was performed in 7 (7%) patients, and was associated with unstable angina (p < 0.01) and revascularization without SES in another site (p < 0.01). Target vessel revascularization was needed in 20 patients (20%), related to dialysis status (p < 0.01) and a revascularization without SES in another site (p < .0001).

CONCLUSIONS

SESs are effective in the treatment of high risk patients with complex in-stent restenosis. Most of cardiac events during follow-up are related to a revascularization without SES in another site.

Drug-Eluting Stents

Percutaneous coronary intervention has evolved dramatically over the past 25 years as coronary stents replaced stand-alone balloon angioplasty. Improvements in stents were made in the 1990s, but a breakthrough occurred in early 2000 with the development of stents that eluted pharmacology agents directly into the vessel wall by means of a controlled release from a durable polymer coating. Various drug-eluting stents were developed,each varying with its delivery platform, polymer coating (or absence of coating),and drug selected for elution. This article describes the clinically available and late developmental drug-eluting stent programs targeted for treating patients who have coronary artery disease.

Treatment of in-stent restenosis with sirolimus-eluting-stents—

Treatment of in-stent restenosis (ISR) remains a therapeutic challenge since many pharmacological and mechanical approaches have shown disappointing results except for brachytherapy. Drug-eluting stents (DES) have been reported to effectively reduce ISR in de novo lesions. We studied 55 consecutive patients with ISR in native coronary arteries and 7 with ISR in saphenous vein grafts (SVG) with elective indication for percutaneous coronary intervention (PCI), who underwent successful implantation with DES. No in-hospital postprocedural major adverse cardiac events were observed. All but one patient (n=61) underwent an angiographic follow-up at 183+/-30 days. Grade of stenosis was assessed by quantitative coronary angiography (QCA) at index procedure and at control angiography. Restenosis (>50%) occurred in 5 patients (8.2%). Target vessel revascularization was performed in an additional 4 patients. Minimal intimal hyperplasia was observed in all segments covered by DES (late loss 0.08+/-0.37 mm, loss index 0.11+/-0.47). One patient suffered from subacute stent thrombosis due to discontinuation of clopidogrel medication. At six month follow-up two patients had died. Death was not related to a restenosis in the treated segment. Conclusion Our experiences with DES treatment of ISR lesions show good angiographic and clinical results at index procedure and at the 6 month follow-up with low sub acute thrombosis rate as compared with existing treatment modalities. Restenosis rate seems to be at least as low as reported for brachytherapy.

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.

The Road to Bioabsorbable Stents: Reaching Clinical Reality?

This article provides an overview of the evolution of revascularization devices since Grüntzig's initial introduction of balloon angioplasty in 1977. In-stent restenosis (ISR) is the major shortcoming of conventional (permanent-implant) stent therapy; even with the innovation and promising benefits of drug-eluting stents, management of ISR is very difficult. ISR is mainly caused by the interaction between the blood and the stent surface and a permanent mechanical irritation of the vascular tissue. Thus stenting technology has moved toward the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely biodegrade in the long term. Preclinical and first clinical experiences with bioabsorbable magnesium stents are discussed.

Use of drug-eluting stents for the treatment of in-stent restenosis in routine clinical practice

BACKGROUND

Although target lesion revascularization (TLR) has been dramatically decreased by using drug-eluting stents (DESs) in de-novo lesions, their efficacy for in-stent restenosis (ISR) has not yet been well established.

METHODS

We retrospectively analysed patients treated for ISR with DESs from three referral hospitals.

RESULTS

Eighty-seven consecutive patients, from June 2002 to April 2004, were included, with a mean age of 64+/-11 years; 83% were men, 32% had diabetes, 47% had had a previous myocardial infarction and 16% had low left ventricular ejection fraction. Angiographic characteristics were as follows: mean vessel diameter, 3.05+/-0.4 mm; lesion length, 17.8+/-7.7 mm; diameter stenosis, 84.0+/-10.7%; and complex lesion, 81%. The restenosis was focal in 45%, diffuse/proliferative in 51.3% and total occlusion in 3.7% of the cases. Sirolimus- and paclitaxel-eluting stents were used in 42 and 58% of the patients, respectively. Stent diameter was 3.1+/-0.3 mm and the length was 26.1+/-5.8 mm. Angiographic success was achieved in all patients, with one patient experiencing a post-procedural non-Q-wave myocardial infarction. At 6-month clinical follow-up, two patients had died from non-cardiac deaths, five had experienced a new TLR (5.7%, four percutaneous and one coronary artery bypass graft) and eight (9.2%) had had major adverse cardiac events. A stress test was performed in 60% of the population; target vessel ischemia was observed in one patient (3.3%).

CONCLUSION

In this non-select cohort of patients, the use of DESs is a safe and effective strategy for ISR lesions.

Brachytherapy for restenosis after stenting for coronary artery disease: its role in the drug-eluting stent era

PURPOSE OF REVIEW

Recent years have brought remarkable changes to the field of interventional cardiology. The need for repeat intervention due to restenosis, the most vexing long-term failure of percutaneous coronary intervention, has been significantly reduced owing to the introduction of two major advances, the vascular brachytherapy (VBT) and the drug-eluting stents (DES).

RECENT FINDINGS

Vascular brachytherapy has demonstrated its efficacy in limiting recurrence of existing in-stent restenosis. The past 2 years have sealed its reputation, with a variety of studies demonstrating its superiority over conventional therapy in challenging patient subsets with high risk for restenosis recurrence. Moreover, the long-term follow-up confirmed durability of this therapy, and the failures of VBT were characterized as easy to treat. Conversely, DES have shown spectacular efficacy at primarily preventing the first restenosis episode following the initial stent placement. Consequently, the role of VBT may be minimized, as the overall need for repeat revascularization is diminished as a result of the wide acceptance of DES. Furthermore, if the capacity of DES to treat in-stent restenosis is confirmed in randomized trials, they may eventually supersede VBT as the therapy of choice for in-stent restenosis.

SUMMARY

At present, VBT is the proven and durable therapeutic choice for patients with complex, diffuse in-stent restenosis who would otherwise have a very poor prognosis for long-term event-free survival. DES have emerged as remarkably effective in minimizing the first restenosis occurrence; they also represent a promising and competitive alternative to VBT for the treatment of in-stent restenosis.

Effectiveness and Safety of Sirolimus-Eluting Stents in the Treatment of Restenosis After Coronary Stent Placement

Background— In-stent restenosis is notoriously difficult to treat by repeat catheter intervention because of its propensity for aggressive recurrent neointimal formation. This study sought to assess the effectiveness and safety of the sirolimus-eluting stent in the treatment of in-stent restenosis.

Methods and Results— The study was designed as a prospective multicenter registry. We included 162 patients with in-stent restenosis of a native coronary artery who had a clinical indication for repeat intervention. Patients were scheduled for follow-up angiography at 6 months. The primary end point was in-lesion late loss. Follow-up angiography was performed in 155 patients. We obtained an in-lesion late loss of 0.08±0.49 mm and a binary restenosis rate of 9.7% (15/155), which prompted reintervention in 7.4% (12/162) at 9 months. The 9-month rate of death was 1.2% (2/162) and that of nonfatal myocardial infarction was 1.2% (2/162).

Conclusions— Sirolimus-eluting stents were highly efficacious and safe in the treatment of in-stent restenosis. Our study provides rationale for the use of sirolimus-eluting stents in the treatment of in-stent restenosis.

Superiority of sirolimus eluting stent compared with intracoronary beta radiation for treatment of in-stent restenosis: a matched comparison

OBJECTIVE

To compare acute and follow up clinical and angiographic results after treatment of in-stent restenosis (ISR) by sirolimus eluting stents (SES) with results obtained after intracoronary radiation therapy (IRT).

DESIGN

Matched pair analysis.

METHODS

62 consecutive ISR lesions (< 30 mm lesion length, reference diameter < 3.5 mm) in 62 patients were treated with SES. From a database of 174 lesions (n = 141 patients) treated for ISR by intracoronary beta radiation, 62 lesions (62 patients) were pair matched with the SES group for diabetes mellitus, lesion length, vessel size, and pattern of ISR. Six month angiographic and 12 month clinical follow up results were obtained.

RESULTS

Baseline clinical and angiographic characteristics were similar between the groups (not significant). SES implantation resulted in significantly lower postprocedural in-lesion diameter stenosis than did IRT (mean (SD) 14.2 (9.5)% v 21.1 (10.6)%, p = 0.001), significantly higher minimum lumen diameter at follow up (1.91 (0.58) v 1.55 (0.72) mm, p = 0.005), and a higher net gain (1.16 (0.55) v 0.77 (0.70) mm, p = 0.002). Angiographic binary in-lesion restenosis rate at six months was 11% in the SES group and 29% in the IRT group (p = 0.046). In 16 ISR lesions SES were used after failed IRT and in 46 lesions for first time ISR. In-lesion late loss was higher after use of SES for failed IRT than after use of SES for first time ISR (0.61 (0.67) mm v 0.24 (0.41) mm, p = 0.018). In a multivariate analysis prior failed IRT was the only independent predictor for recurrent restenosis after SES for ISR (p = 0.052, odds ratio 5.8). Six patients (10%) in the SES group and 17 patients (27%) in the IRT group underwent target lesion revascularisation during the 12 months of follow up (p = 0.022).

CONCLUSIONS

In this non-randomised matched cohort SES achieved acute and follow up results superior to IRT for treatment of ISR even if cases of failed IRT are included. Failed IRT is a predictor of impaired SES effectiveness.

Guidelines for percutaneous coronary interventions. The Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology

In patients with stable CAD, PCI can be considered a valuable initial mode of revascularization in all patients with objective large ischaemia in the presence of almost every lesion subset, with only one exception: chronic total occlusions that cannot be crossed. In early studies, there was a small survival advantage with CABG surgery compared with PCI without stenting. The addition of stents and newer adjunctive medications improved the outcome for PCI. The decision to recommend PCI or CABG surgery will be guided by technical improvements in cardiology or surgery, local expertise, and patients' preference. However, until proved otherwise, PCI should be used only with reservation in diabetics with multi-vessel disease and in patients with unprotected left main stenosis. The use of drug-eluting stents might change this situation. Patients presenting with NSTE-ACS (UA or NSTEMI) have to be stratified first for their risk of acute thrombotic complications. A clear benefit from early angiography (<48 h) and, when needed, PCI or CABG surgery has been reported only in the high-risk groups. Deferral of intervention does not improve outcome. Routine stenting is recommended on the basis of the predictability of the result and its immediate safety. In patients with STEMI, primary PCI should be the treatment of choice in patients presenting in a hospital with PCI facility and an experienced team. Patients with contra-indications to thrombolysis should be immediately transferred for primary PCI, because this might be their only chance for quickly opening the coronary artery. In cardiogenic shock, emergency PCI for complete revascularization may be life-saving and should be considered at an early stage. Compared with thrombolysis, randomized trials that transferred the patients for primary PCI to a 'heart attack centre' observed a better clinical outcome, despite transport times leading to a significantly longer delay between randomization and start of the treatment. The superiority of primary PCI over thrombolysis seems to be especially clinically relevant for the time interval between 3 and 12 h after onset of chest pain or other symptoms on the basis of its superior preservation of myocardium. Furthermore, with increasing time to presentation, major-adverse-cardiac-event rates increase after thrombolysis, but appear to remain relatively stable after primary PCI. Within the first 3 h after onset of chest pain or other symptoms, both reperfusion strategies seem equally effective in reducing infarct size and mortality. Therefore, thrombolysis is still a viable alternative to primary PCI, if it can be delivered within 3 h after onset of chest pain or other symptoms. Primary PCI compared with thrombolysis significantly reduced stroke. Overall, we prefer primary PCI over thrombolysis in the first 3 h of chest pain to prevent stroke, and in patients presenting 3-12 h after the onset of chest pain, to salvage myocardium and also to prevent stroke. At the moment, there is no evidence to recommend facilitated PCI. Rescue PCI is recommended, if thrombolysis failed within 45-60 min after starting the administration. After successful thrombolysis, the use of routine coronary angiography within 24 h and PCI, if applicable, is recommended even in asymptomatic patients without demonstrable ischaemia to improve patients' outcome. If a PCI centre is not available within 24 h, patients who have received successful thrombolysis with evidence of spontaneous or inducible ischaemia before discharge should be referred to coronary angiography and revascularized accordingly--independent of 'maximal' medical therapy.

Relationship of Late Loss in Lumen Diameter to Coronary Restenosis in Sirolimus-Eluting Stents

Background— Observed rates of restenosis after drug-eluting stenting are low (<10%). Identification of a reliable and powerful angiographic end point will be useful in future trials.

Methods and Results— Late loss (postprocedural minimum lumen diameter minus 8-month minimum lumen diameter) was measured in the angiographic cohorts of the SIRIUS (n=703) and E-SIRIUS (n=308) trials. Two techniques, the standard normal approximation and an optimized power transformation, were used to predict binary angiographic restenosis rates and compare them with observed restenosis rates. The mean in-stent late loss observed in the SIRIUS trial was 0.17±0.45 mm (sirolimus) versus 1.00±0.70 mm (control). If a normal distribution was assumed, late loss accurately estimated in-stent binary angiographic restenosis for the control arm (predicted 35.4% versus observed 35.4%) but underestimated it in the sirolimus arm (predicted 0.6% versus observed 3.2%). Power transformation improved the reliability of the estimate in the sirolimus arm (predicted 3.2% [CI 1.0% to 6.7%]) with similar improvements in the E-SIRIUS trial (predicted 4.0% [CI 1.2% to 7.0%] versus observed 3.9%). In the sirolimus-eluting stent arm, in-stent late loss correlated better with target-lesion revascularization than in-segment late loss (c-statistic=0.915 versus 0.665).

Conclusions— Because distributions of late loss with a low mean are right-skewed, the use of a transformation improves the accuracy of predicting low binary restenosis rates. Late loss is monotonically correlated with the probability of restenosis and yields a more efficient estimate of the restenosis process in the era of lower binary restenosis rates.

The impact of the introduction of drug-eluting stents on the clinical practice of surgical and percutaneous treatment of coronary artery disease

AIMS

Sirolimus-eluting stents (SES) have recently been shown to reduce restenosis in selected patients. The impact of this new stent on the use of coronary bypass graft (CABG) surgery or percutaneous coronary intervention (PCI) in clinical practice is yet unknown. Therefore, we investigated the impact of SES on the clinical practice of CABG and PCI in a series of unselected consecutive patients.

METHODS AND RESULTS

Between April and October 2002, a policy of SES implantation for all procedures has been instituted in our hospital. In total, 798 patients were referred to PCI and 275 to CABG (SES group). A control group was composed of all interventions (806 PCI and 314 CABG) performed during the preceding 6 months (pre-SES). The main outcome was the occurrence of major adverse cardiac events (MACE) at 15 months. In the SES era, a significant shift was noted in the PCI group towards more multi-vessel stenting (28 vs. 24%; P<0.05), more bifurcation stenting (18 vs. 7%; P<0.0001), and the use of more stents (1.9 vs. 1.5; P<0.05). In the PCI elective patients, a shift was noted towards more three-vessel disease (pre-SES: 16% vs. SES: 23%; P=0.02). Furthermore, we observed a shift in the CABG group towards more impaired LV function (pre-SES: 34% vs. SES: 41%; P=0.02) and towards more three-vessel disease (pre-SES: 67% vs. SES: 75%; P=0.03). Overall, the cumulative MACE percentages at 1 year after coronary revascularization (PCI and CABG combined) decreased from 16.8 to 13.8% (P=0.03). The cumulative MACE percentages in the pure SES group and the pre-SES bare metal stent group at 12 months were 15.6 and 19.8%, respectively (P<0.01).

CONCLUSION

The introduction of the SES has certainly had an impact on the treatment strategy of coronary artery disease (CAD). Increased use of these stents allows more complex coronary anatomy to be treated by PCI, and results in lower repeat revascularization rates.

Contemporary use of drug-eluting stents

Since the era of balloon angioplasty, stents have been a revolutionary advance in the treatment of severe coronary artery disease. However, one of the major limitations is in-stent restenosis. Although brachytherapy was found to be an effective treatment, the goal remains to develop a kind of stent that will not restenose. The emergence of drug-eluting stents provided a novel solution for the reduction of restenosis. The currently approved indication for drug-eluting stents by the US Food and Drug Administration is for discrete, de novo lesions in native vessels with reference vessel diameters of 2.5 to 3.5 mm. However, in the worldwide daily practice, there have been numerous off-label uses of drug-eluting stents, and their long-term follow-up and experience in more complex lesions are accumulating. This article reviews the current off-label uses of drug-eluting stents. The majority of the supporting data are from registry and observational studies, yet many studies are limited by small sample sizes. Therefore, large, prospective, randomized, double-blind, and controlled trials are definitely warranted to further support current practice. Nevertheless, the "real world" unrestricted uses of drug-eluting stents seem to be the current trend in the interventional field.

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.

Late thrombosis following treatment of in-stent restenosis with drug-eluting stents after discontinuation of antiplatelet therapy

Drug-eluting stent usage has become commonplace for the percutaneous treatment of de novo coronary lesions, but the safety and efficacy profile for their evolving usage in restenotic lesions is largely unknown. We report three cases of angiographically confirmed drug-eluting stent thrombosis following treatment of restenotic lesions that occurred late (193, 237, and 535 days) and shortly after interruption of antiplatelet therapy. All three patients suffered ST elevation myocardial infarction, and there was one death. Further studies are necessary to better define the associated risk and ideal duration of antiplatelet therapy necessary in this cohort of patients with restenotic lesions.