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

Drug Eluting Stent Technology

The authors discuss the mechanism of action, clinical trial data, and economic impact of both the paclitaxel and sirolimus drug eluting stents (DESs). Both DESs have been approved by the Food and Drug Administration for the treatment of native coronary arteries to prevent in-stent restenosis (ISR), which patients have experienced since the advent of balloon angioplasty and the bare metal stent. In-stent restenosis, which manifests itself as ischemic symptoms in patients, occurs as a result of the healing process after stent implantation. Until now, there has not been an effective method to prevent ISR. The sirolimus and paclitaxel DESs elute agents that act locally by different mechanisms to reduce neointimal hyperplasia, which is primarily responsible for ISR. Both DESs are capable of reducing the rate of ISR. There are certain physical and mechanistic differences between the 2 stents; the stents have not been compared head to head. Currently, they are indicated for uncomplicated native coronary lesions. Further investigation is needed to define their roles in the treatment of more complex lesions.

Use of intravascular ultrasound vs. optical coherence tomography for mechanism and patterns of in-stent restenosis among bare metal stents and drug eluting stents

This article is a perspective responses to the "Mechanisms and Patterns of Intravascular Ultrasound In-Stent Restenosis Among Bare Metal Stents and First- and Second-Generation Drug-Eluting Stents" by Goto et al., The above mentioned article outlines the use of intravascular ultrasound (IVUS) in visualizing the patterns and mechanisms of in-stent restenosis (ISR) post percutaneous coronary intervention (PCI). Although IVUS is an appropriate method of choice for this scenario, IVUS has certain limitations which can be overcome by using optical coherent tomography (OCT). OCT is not only able to overcome IVUS's limitations but is also able to provide additional information to enhance the understanding of in-stent restenotic lesions. This article also outlines the future directions for OCT both in clinical and investigation settings.

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.

Optical coherence tomography patterns of stent restenosis

BACKGROUND

Stent restenosis is an infrequent but poorly understood clinical problem in the drug-eluting stent era. The aim of the study was to evaluate the morphologic characteristics of stent restenosis by optical coherence tomography (OCT).

METHODS

Patients (n = 24, 25 vessels) presenting with angiographically documented stent restenosis were included. Quantitative OCT analysis consisted of lumen and stent area measurement and calculation of restenotic tissue area and burden. Qualitative restenotic tissue analysis included assessment of tissue structure, backscattering and symmetry, visible microvessels, lumen shape, and presence of intraluminal material.

RESULTS

By angiography, restenosis was classified as diffuse, focal, and at the margins in 9, 11, and 5 vessels, respectively. By OCT, restenotic tissue structure was layered in 52%, homogeneous in 28%, and heterogeneous in 20%. The predominant backscatter was high in 72%. Microvessels were visible in 12%. Lumen shape was irregular in 28% and there was intraluminal material in 20%. The mean restenotic tissue symmetry ratio was 0.58 +/- 0.19. Heterogeneous and low scattering restenotic tissue was more frequent in focal (45.5% and 54.5%, respectively) than in diffuse (0 and 11.1%) and margin restenosis (0 and 0%) (P = .005 for heterogeneous, P = .03 for low scattering). Restenosis patients with unstable angina symptoms presented more frequently irregular lumen shape (60 vs 6.7%, P = .007). Stents implanted </=12 months ago had more frequently restenotic tissue with layered appearance (84.6% vs 16.7%, P = .003).

CONCLUSIONS

We demonstrate the ability of OCT to identify differential patterns of restenotic tissue after stenting. This information could help in understanding the mechanism of stent restenosis.

Drug‐eluting stents for the treatment of in‐stent restenosis – ‘real world’ double centre experience in consecutive patients

OBJECTIVES

We evaluated clinical outcome of consecutive patients with in stent restenosis (ISR) treated with drug-eluting stents (DES) at two intervention centres from April 2002 to April 2004, reflecting 'real world' practice.

BACKGROUND

ISR is the major limitation to successful long-term outcome after implantation of bare metal stents during percutaneous coronary intervention (PCI). The optimal strategy for the treatment of ISR has yet to be determined.

METHODS

121 consecutive patients with significant ISR were treated with DES. Sirolimus DES were used in 60 patients and paclitaxel DES in the remainder. All patients were followed up to evaluate the incidence of major adverse cardiac events (MACE), angina class and clinically driven angiography. Data were collected between 7 and 27 months after the procedure (mean follow up of 16.5 months).

RESULTS

Overall MACE rate at 16.5 months was 13.2% (16 patients) including 4 deaths (3%). Fifteen (12.3%) patients underwent clinically driven angiography. Eight patients (6.6%) developed ISR within the treated segment, of whom, four underwent further PCI and 4 CABG. Mean Canadian angina class decreased from 2.46+/-0.7 pre-procedure to 0.69+/-0.6 at follow up. All patients achieved an improvement in angina, with 59% being rendered angina free and 87% free of MACE. There were no differences in clinical outcome in those who received a paclitaxel and sirolimus DES.

CONCLUSIONS

The use of DES implantation for the treatment of ISR is safe, effective and associated with low recurrence rates in a 'real world' large cohort of patients with a complex mix of anatomical and clinical factors.

Intracoronary β‐irradiation enhances balloon‐injury‐induced tissue factor expression in the porcine injury model

Intracoronary brachytherapy (ICBT) effectively reduces restenosis but is associated with late thrombosis. Since tissue factor (TF) is an important mediator of arterial thrombosis, we tested the hypothesis that ICBT results in persistently augmented TF expression. Coronary arteries from 12 pigs were randomized to: control (C; no injury), oversized balloon injury (BI), or BI followed by ICBT. Animals were sacrificed at 1, 7, 14, or 60 days postprocedure, and coronary arteries collected for expression analyses and immunostaining. ICBT-treated arteries had higher TF antigen and activity at all time-points compared to BI arteries (Western blot: 16 571 +/- 2090 vs 10 135 +/- 2939 densitometric units, p = 0.001; ELISA: 0.42 +/- 0.13 nM vs 0.25 +/- 0.14 nM, p = 0.001; TF activity assay: 0.303 +/- 0.11 nM vs 0.18 +/- 0.07 nM, p = 0.01; immunohistochemical staining: 30.6 +/- 6.6% vs 11.5% +/- 3.2%, p = 0.01). TF expression increased following BI, increased further following ICBT, and persisted for the duration of the study. We conclude that TF expression increases after BI, but is further increased and persists for a longer duration following ICBT, suggesting that a TF-mediated mechanism may play a role in late thrombosis following ICBT.

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.

The Sirolimus-eluting coronary stent in daily routine practice in Germany: trends in indications over the years. Results from the prospective multi-centre German Cypher Stent Registry

BACKGROUND

Drugeluting coronary stents (DES) are increasingly used during percutaneous coronary interventions (PCI). Due to limited budgets in Germany, no special reimbursement has been given for their use and therefore they were mainly used in selected patients.

METHODS

In order to determine the change in indications in patients treated with a Sirolimus-eluting stent (SES) in daily clinical practice between 2002 and 2005, we analysed data from a prospective multi-centre DES registry, the German Cypher Stent Registry.

RESULTS

From April 2002 until September 2005, 11 507 patients at 132 hospitals, who received at least one SES during their PCI, were included. Between 2002 and 2005, the median age of patients increased from 63 years to 66 years (p for trend <0.0001), whereas the prevalence of prior coronary bypass surgery (p<0.0001) and prior PCI (p<0.001) significantly decreased. Initial presentation of patients was stable over time, with a small increase of patients treated for non-ST elevation myocardial infarction (p=0.05). We found a significant increase in the treatment of complex stenoses (p<0.0001) as well as an increase in the proportion of chronic total occlusions (p<0.01). There was a steady increase in the proportion of patients treated for de novo lesions (p<0.0001), which was accompanied by a relative decrease in the proportion of patients treated for in-stent restenosis (p<0.0001). Concerning interventional characteristics a significant increase in the length of SES implanted per lesion, the numbers of SES implanted per lesion as well as an increase of the proportion of patients treated for more than one stenosis during one intervention could be observed (all p<0.0001). There was a significant decrease in the use of glycoprotein II b/IIIa antagonists during the PCI (2002: 26.5 to 14.2% in 2005, p<0.0001). MACE rates until hospital discharge did not change significantly over time.

CONCLUSIONS

Between 2002 and 2005 there were two trends in the use of SES: a) a significant increase in the use of SES for de novo lesions and b) a significant trend to use SES for longer lesions, smaller arteries, more complex lesions and more SES per lesion. In summary these findings indicate that still SES are mainly used in patients with lesions that are at high risk for restenosis.

Current understanding of coronary in-stent restenosis. Pathophysiology, clinical presentation, diagnostic work-up, and management

In-stent restenosis is the limiting entity following coronary stent implantation. It is associated with significant morbidity and cost and thus represents a major clinical and economical problem. Worldwide, approximately 250 000 in-stent restenotic lesions per year have to be dealt with. The pathophysiology of instent restenosis is multifactorial and comprises inflammation, smooth muscle cell migration and proliferation and extracellular matrix formation, all mediated by distinct molecular pathways. Instent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50% regardless of the mechanical angioplasty device used. Much more favourable results were reported for the adjunctive irradiation of the in-stent restenotic lesion, with a consistent reduction of the incidence of repeat in-stent restenosis by 50%. Data from the first clinical trials on drug-eluting stents for the treatment of in-stent restenosis have shown very much promise yielding this strategy likely to become the treatment of choice. This review outlines the histological and molecular findings of the pathophysiology, the epidemiology, the predictors and the diagnostic work-up of in-stent restenosis and puts emphasis on the various treatment options for its prevention and therapy.

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.

Predictors of outcome after sirolimus-eluting stent implantation for complex in-stent restenosis

Few data are available on the effectiveness of sirolimus-eluting stent implantation for the treatment of in-stent restenosis, and no data exist about the predictors of outcome after sirolimus-eluting stent implantation for complex in-stent restenosis (diffuse, proliferative, or total occlusion). From April 2002 to May 2004, 136 patients with 161 complex in-stent restenoses underwent sirolimus-eluting stent implantation. At 9 months, 5 patients had died (3 of cardiac and 2 of noncardiac causes), no reinfarctions had occurred, and 11 target vessel revascularization procedures had been performed. The target vessel revascularization rate was 8%, and the in-segment binary restenosis rate was 17%. The predictors of the risk of recurrence were unstable angina as the clinical presentation of in-stent restenosis, an ostial location of the target lesion, lesion length, and sirolimus-eluting stent diameter < or =2.5 mm.

Angiographic and clinical outcome for the treatment of in-stent restenosis with sirolimus-eluting stent compared to vascular brachytherapy

BACKGROUND

With the use of coronary stents for the treatment of coronary artery disease, in-stent restenosis became a major clinical problem. In this non-randomized study, we examined the use of stent-based delivery of sirolimus (rapamycin) for the treatment of in-stent restenosis in comparison to intracoronary beta-brachytherapy, regarding the clinical effectiveness and the angiographic results for the treatment of in-stent restenosis after 6-9 months.

METHODS AND RESULTS

Between July 2001 and May 2002, 28 patients (65+/-11 years) with instent restenosis were treated with intracoronary brachytherapy. Consecutively, between May 2002 and April 2003, 28 patients (65+/-10 years) with in-stent restenosis were treated with the implantation of a sirolimus-eluting stent (SES). Patients with in-stent restenosis treated by implantation of a SES had significantly lower incidence of in-stent restenosis (1/28 (3.6%) vs 10/28 (36%); p=0.007) and insegment restenosis (4/28 (14%) vs 14/28 (50%); p=0.013) compared to patients treated with brachytherapy. Target lesion and target vessel revascularization rate tended to be lower in the SES group (14 vs 25%) but did not yet reach statistical significance. One patient died in the group treated by implantation of a SES eight months after stenting, one patient suffered from myocardial infarction due to a subtotal in-stent restenosis after brachytherapy. Two patients after brachytherapy underwent surgical revascularization due to recurrent in-stent restenosis similar to the patient with in-stent restenosis after SES implantation.

CONCLUSION

In this study we show the feasibility and safety of the treatment of in-stent restenosis by implantation of sirolimus-eluting stents and demonstrate a lower incidence of recurrent in-stent restenosis as well as lower late luminal loss compared to treatment by intravascular brachytherapy.

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.

Adenovirus-Mediated Intraarterial Delivery of PTEN Inhibits Neointimal Hyperplasia

Objective— Phosphoinositide (PI) 3-kinase promotes vascular smooth muscle cell (VSMC) responses necessary for neointimal hyperplasia. We recently demonstrated that the inositol 3-phosphatase PTEN is expressed in VSMCs and that its overexpression inhibits these cellular responses. The purpose of this study was to determine the effects of adenovirus-mediated overexpression of PTEN on neointimal hyperplasia in vivo in the rat carotid injury model.

Methods and Results— Rat carotid arteries were balloon-injured and treated with a recombinant control adenovirus (AdEV) (n=6), an adenovirus encoding wild-type PTEN (AdPTEN) (n=8), or phosphate-buffered saline (sham) (n=5). Injured vessels demonstrated PTEN overexpression by Western blotting and immunohistochemistry after AdPTEN treatment. Neointimal hyperplasia was assessed 2 weeks after balloon injury and adenovirus administration. Compared with controls, AdPTEN treatment significantly decreased neointimal area and percent stenosis. To investigate the mechanisms of action of AdPTEN, vessels were harvested 3 days after balloon injury and virus infection. AdPTEN significantly increased medial cell apoptosis while decreasing proliferation of the remaining viable cells.

Conclusions— PTEN overexpression potently inhibits neointimal hyperplasia through induction of apoptosis and inhibition of medial cell proliferation. These findings suggest that modulation of PTEN expression or activity may be a viable approach to treat neointimal hyperplasia.

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.

Efficacy and safety of oral sirolimus to inhibit in-stent intimal hyperplasia

Sirolimus systemic administration has shown marked inhibition of neointimal hyperplasia (NIH) after balloon angioplasty in porcine models. In this pilot study, we tested the hypothesis that oral sirolimus is safe and effective to inhibit in-stent NIH and therefore to prevent and treat in-stent restenosis (ISR). Twelve patients (18 lesions) with high risk for ISR, including 8 ISR lesions, were admitted. One day before the procedure, patients were given a 15 mg loading dose of oral sirolimus, followed by 5 mg daily for 28 days, with weekly whole blood level measurements. The daily dose was adjusted to keep the concentration at 10-15 ng/ml. Sirolimus was well tolerated by all patients but one, who died at the end of the third week of treatment. The 4- and 8-month follow-up revealed an angiographic late loss of 0.40 +/- 0.24 and 0.67 +/- 0.45 mm (P < 0.01), respectively. At the same time points, the intravascular ultrasound in in-stent relative volumetric obstruction was 14.4% +/- 9.1% and 23.2% +/- 10.1% (P < 0.01), respectively. At 24-month clinical follow-up, adverse events were one (8.3%) death, two (11.1%) target lesion, and four (22.2%) target vessel revascularizations. In conclusion, in this small group of high-risk ISR patients, oral sirolimus inhibited NIH and therefore may be an effective strategy for the prevention and treatment of ISR.

Clinical Experiences Using Everolimus-Eluting Stents in Patients with Coronary Artery Disease

Despite the growing use of drug-eluting stents, restenosis remains to occur especially in high risk subgroups like patients with diffuse in-stent restenosis. This observation is supporting the search for new and potentially even more effective drug eluting stent systems. Everolimus has been used in conjunction with a new bioabsorbable polymer and gave promising results in initial clinical studies. In FUTURE I, a single-center, single-blinded randomized safety and feasibility study enrolling 15 patients with bare metal stents and 27 patients with everolimus-coated stents, 30-day MACE rate was 0% in both groups. In-stent late loss at six months was 0.83 mm in the control group and 0.10 mm in the everolimus group (p < 0.0001). In FUTURE II, a randomized multi-center study, a total of 64 patients were enrolled confirming safety and feasibility. After 6 months late loss was 0.85 mm in the control group and 0.12 mm in the everolimus group (p < 0.001).

Comparison of clinical and angiographic outcome of sirolimus-eluting stent implantation versus cutting balloon angioplasty for coronary in-stent restenosis

Sixty in-stent restenotic lesions were treated with sirolimus-eluting stent implantation and retrospectively compared with a group of matched lesions treated with cutting balloon angioplasty. The results indicate a good safety profile of the procedure and a 57% reduction in the incidence of recurrent restenosis in comparison with cutting balloon angioplasty.

Drug-coated Stents

Since its introduction in 1977, the success of percutaneous interventional cardiology has been limited by the occurrence of restenosis. Drug-eluting stents, particularly sirolimus- and paclitaxel-coated stents, have been shown in randomized controlled trials to dramatically reduce restenosis in single, de novo, native coronary arteries. Over the last 2 years, investigators have reported that these stents can also reduce restenosis in more complex patient situations such as in diabetics, during acute coronary syndromes, in long atherosclerotic lesions and small arteries, and even after in-stent restenosis. These outcomes increase the clinical value of this technology to "real world" practice. This article reviews the current state of our knowledge regarding drug-eluting stents and identifies areas for further research.

Two-year outcomes of repeated brachytherapy in patients with restenosis after intracoronary radiation therapy

This study compared the 2-year outcomes of repeat brachytherapy (n = 10) and conventional percutaneous intervention (n = 14) in patients with restenosis after intracoronary brachytherapy with a rhenium-188-filled balloon system. The short-term target lesion revascularization rate was significantly lower in the repeat brachytherapy group (0% vs 36%, p = 0.038), and additional target lesion revascularization was required in 2 patients with repeat brachytherapy during 2-year follow-up. There were no vascular complications related to repeat brachytherapy.

Routine sirolimus eluting stent implantation for unselected in-stent restenosis: insights from the rapamycin eluting stent evaluated at Rotterdam Cardiology Hospital (RESEARCH) registry

OBJECTIVE

To assess the effectiveness of routine sirolimus eluting stent (SES) implantation for unselected patients with in-stent restenosis and to provide preliminary information about the angiographic outcome for lesion subgroups and for different in-stent restenosis patterns.

DESIGN

Prospective, single centre registry.

SETTING

Tertiary referral centre.

PATIENTS

44 consecutive patients (53 lesions) without previous brachytherapy who were treated with SES for in-stent restenosis were evaluated. Routine angiographic follow up was obtained at six months and the incidence of major adverse cardiovascular events was evaluated.

RESULTS

At baseline, 42% of the lesions were focal, 21% diffuse, 26% proliferative, and 11% total occlusions. Small vessel size (reference diameter < or = 2.5 mm) was present in 49%, long lesions (> 20 mm) in 30%, treatment of bypass grafts in 13%, and bifurcation stenting in 18%. At follow up, post-SES restenosis was observed in 14.6%. No restenosis was observed in focal lesions. For more complex lesions, restenosis rates ranged from 20-25%. At the one year follow up, the incidence of death was 0, myocardial infarction 4.7% (n = 2), and target lesion revascularisation 16.3% (n = 7). The target lesion was revascularised because of restenosis in 11.6% (n = 5).

CONCLUSIONS

Routine SES implantation is highly effective for focal in-stent restenosis and appears to be a promising strategy for more complex patterns of restenosis.

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

The impact of the use of sirolimus-eluting stents (SESs) in the treatment of in-stent restenosis in previously irradiated sites has not been adequately evaluated. Fifteen consecutive patients who underwent percutaneous coronary interventions using SESs in lesion sites previously intervened with intracoronary radiation therapy were identified. All stents were implanted successfully, and there were no major in-hospital complications. At 30-day follow-up, there was 1 case of subacute thrombosis that led to target lesion revascularization (TLR). At 6 months, 2 patients underwent TLR because of recurrent angina with angiographic restenosis, and 1 patient underwent target vessel revascularization distally to the SES site; no other major adverse cardiac events occurred at long-term follow-up (mean 17 +/- 8 months).

Sirolimus-Eluting Coronary Stents: Novel Devices for the Management of Coronary Artery Disease

Despite major technological advances in the practice of percutaneous coronary intervention, restenosis of the treated arteries remains a challenge for many interventional cardiologists. Sirolimus is a macrolide antibiotic with potent antifungal, immunosuppressive, and antimitotic activities. Sirolimus inhibits in-stent restenosis via 2 major mechanisms of action: by blocking the process of neointimal hyperplasia by inhibiting smooth muscle cell proliferation and by inhibiting inflammatory cell activity. In pivotal clinical trials, the sirolimus-eluting stent has demonstrated significant improvements in angiographic and clinical outcomes compared with bare metal stents in patients with de novo lesions in native coronary arteries. Since the systemic exposure of sirolimus in patients who received the drug-eluting stent is minimal, adverse effects resulting from systemic exposure of sirolimus are unlikely to occur. Further studies are needed to determine the safety and effectiveness of sirolimus-eluting stents in patients with more complex coronary artery lesions. In addition, the long-term safety, efficacy, and cost-effectiveness of this novel drug-eluting device will need to be established in ongoing clinical trials. This review article focuses on the pharmacology as well as clinical studies of the sirolimus-eluting stent.

Clinical, angiographic, and procedural predictors of angiographic restenosis after sirolimus-eluting stent implantation in complex patients: an evaluation from the Rapamycin-Eluting Stent Evaluated At Rotterdam Cardiology Hospital (RESEARCH) study

BACKGROUND

The factors associated with the occurrence of restenosis after sirolimus-eluting stent (SES) implantation in complex cases are currently unknown.

METHODS AND RESULTS

A cohort of consecutive complex patients treated with SES implantation was selected according to the following criteria: (1) treatment of acute myocardial infarction, (2) treatment of in-stent restenosis, (3) 2.25-mm diameter SES, (4) left main coronary stenting, (5) chronic total occlusion, (6) stented segment >36 mm, and (7) bifurcation stenting. The present study population was composed of 238 patients (441 lesions) for whom 6-month angiographic follow-up data were obtained (70% of eligible patients). Significant clinical, angiographic, and procedural predictors of post-SES restenosis were evaluated. Binary in-segment restenosis was diagnosed in 7.9% of lesions (6.3% in-stent, 0.9% at the proximal edge, 0.7% at the distal edge). The following characteristics were identified as independent multivariate predictors: treatment of in-stent restenosis (OR 4.16, 95% CI 1.63 to 11.01; P<0.01), ostial location (OR 4.84, 95% CI 1.81 to 12.07; P<0.01), diabetes (OR 2.63, 95% CI 1.14 to 6.31; P=0.02), total stented length (per 10-mm increase; OR 1.42, 95% CI 1.21 to 1.68; P<0.01), reference diameter (per 1.0-mm increase; OR 0.46, 95% CI 0.24 to 0.87; P=0.03), and left anterior descending artery (OR 0.30, 95% CI 0.10 to 0.69; P<0.01).

CONCLUSIONS

Angiographic restenosis after SES implantation in complex patients is an infrequent event, occurring mainly in association with lesion-based characteristics and diabetes mellitus.

Contribution of stent underexpansion to recurrence after sirolimus-eluting stent implantation for in-stent restenosis

BACKGROUND

We used intravascular ultrasound (IVUS) to evaluate recurrence after sirolimus-eluting stent (SES) implantation treatment of in-stent restenosis (ISR).

METHODS AND RESULTS

Forty-eight ISR lesions (41 patients with objective evidence of ischemia) were treated with SES. Recurrent ISR was identified in 11 lesions (all focal); repeat revascularization was performed in 10. These were compared with 16 patients (19 lesions) without recurrence as documented by angiography. Nine of 11 recurrent lesions had a minimum stent area (MSA) <5.0 mm2 versus 5 of 19 nonrecurrent lesions (P=0.003); 7 of 11 recurrent lesions had an MSA <4.0 mm2 versus 4 of 19 nonrecurrent lesions (P=0.02); and 4 of 11 recurrent lesions had an MSA <3.0 mm2 versus 1 of 19 nonrecurrent lesions (P=0.03). A gap between SESs was identified in 3 of 11 recurrences versus 1 of 19 nonrecurrent lesions.

CONCLUSIONS

Stent underexpansion is a significant cause of failure after SES implantation treatment of ISR.