Treatment of in-stent restenosis using a paclitaxel-eluting stent: acute results and long-term follow-up of a matched-pair comparison with intracoronary $beta;-radiation therapy

Health Care Monitoring and Treatment for Coronary Artery Diseases: Challenges and Issues

In-stent restenosis concerning the coronary artery refers to the blood clotting-caused re-narrowing of the blocked section of the artery, which is opened using a stent. The failure rate for stents is in the range of 10% to 15%, where they do not remain open, thereby leading to about 40% of the patients with stent implantations requiring repeat procedure within one year, despite increased risk factors and the administration of expensive medicines. Hence, today stent restenosis is a significant cause of deaths globally. Monitoring and treatment matter a lot when it comes to early diagnosis and treatment. A review of the present stent monitoring technology as well as the practical treatment for addressing stent restenosis was conducted. The problems and challenges associated with current stent monitoring technology were illustrated, along with its typical applications. Brief suggestions were given and the progress of stent implants was discussed. It was revealed that prime requisites are needed to achieve good quality implanted stent devices in terms of their size, reliability, etc. This review would positively prompt researchers to augment their efforts towards the expansion of healthcare systems. Lastly, the challenges and concerns associated with nurturing a healthcare system were deliberated with meaningful evaluations.

Linear Micro-patterned Drug Eluting Balloon (LMDEB) for Enhanced Endovascular Drug Delivery

In-stent restenosis (ISR) often occurs after applying drug eluting stents to the blood vessels suffering from atherosclerosis or thrombosis. For treatment of ISR, drug eluting balloons (DEB) have been developed to deliver anti-proliferative drugs to the lesions with ISR. However, there are still limitations of DEB such as low drug delivery efficiency and drug loss to blood flow. Although most researches have focused on alteration of drug formulation for more efficient drug delivery, there are few studies that have attempted to understand and utilize the contact modality of DEB drug delivery. Here, we developed a linear micro-patterned DEB (LMDEB) that applied higher contact pressure to enhance drug stamping to vascular tissue. Ex vivo and in vivo studies confirmed that higher contact pressure from micro-patterns increased the amount of drug delivered to the deeper regions of vessel. Finite element method simulation also showed significant increase of contact pressure between endothelium and micro-patterns. Quantitative analysis by high performance liquid chromatography indicated that LMDEBs delivered 2.3 times higher amount of drug to vascular tissue in vivo than conventional DEBs. Finally, efficacy studies using both atherosclerotic and ISR models demonstrated superior patency of diseased vessels treated with LMDEB compared to those treated with DEB.

Drug-eluting balloons versus drug-eluting stents for the management of in-stent restenosis: A meta-analysis of randomized and observational studies

OBJECTIVES

The aim of this study was to evaluate the efficacy of drug-eluting balloons (DEB) with drug-eluting stents (DES) in patients with in-stent restenosis (ISR).

BACKGROUND

DES implantation and DEB were available strategies in percutaneous coronary intervention (PCI) for ISR, but the optimal management for ISR lesions remains controversial.

METHODS

Electronic databases were searched for randomized controlled trials and observational cohort studies which reported the clinical outcomes of using DEB comparing with DES implantation in patients with ISR. Clinical endpoints such as major adverse cardiovascular events (MACE), death, and myocardial infarction were assessed.

RESULTS

Five randomized controlled trials and five observational cohort studies with 962 patients in the DEB group and 908 patients in the DES group met inclusion criteria. There was no significant difference between DEB and DES in major clinical outcomes, such as MACE (OR 1.01; 95% CI: 0.64-1.58; p=0.97; I²=0%), all-cause death (OR 1.04; 95% CI: 0.54-1.98; p=0.91; I²=0%), cardiovascular death (OR 1.44; 95% CI: 0.57-3.65; p=0.44; I²=0%), stent thrombosis (OR 0.61; 95% CI: 0.16-2.33; p=0.47; I²=0%), and myocardial infarction (OR 1.02; 95% CI: 0.53-1.94; p=0.96; I²=0%). DEB was associated with a significant increase in target lesion revascularization (OR 1.54; 95% CI: 1.10-2.15; p=0.01; I²=57%).

CONCLUSION

Treatment of ISR using DEB led to comparable clinical outcomes with DES implantation.

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.

The efficacy and safety of drug-eluting balloons for the treatment of in-stent restenosis as compared with drug-eluting stents and with conventional balloon angioplasty

BACKGROUND/AIMS

Treatment of coronary in-stent restenosis (ISR) is still associated with a high incidence of recurrence. We aimed to compare the efficacy and safety of drug-eluting balloons (DEB) for the treatment of ISR as compared with conventional balloon angioplasty (BA) and drug-eluting stents (DES).

METHODS

Between January 2006 and May 2012 a total of 177 patients (188 lesions, 64.1 ± 11.7 years old) who underwent percutaneous coronary intervention for ISR were retrospectively enrolled. Clinical outcomes were compared between patients treated with DEB (n = 58, 32.8%), conventional BA (n = 65, 36.7%), or DES (n = 54, 30.5%). The primary end point was a major adverse cardiac event (MACE), defined as a composite of cardiac death, myocardial infarction, and target lesion revascularization(TLR).

RESULTS

Baseline characteristics were not different except for a history of previous MI, which was more frequent in patients treated by conventional BA or DES than in patients treated by DEB (40.0% vs. 48.1% vs. 17.2%, respectively, p = 0.002). The total incidences of MACEs were 10.7%, 7.4%, and 15.4% in patients treated by DEB, DES, or conventional BA, respectively (p > 0.05). TLR was more frequent in patients treated by conventional BA than in patients treated by DEB or DES, but this was not statistically significant (10.8% vs. 6.9% vs. 3.7%, p > 0.05 between all group pairs, respectively).

CONCLUSIONS

This study showed that percutaneous coronary intervention using DEB might be a feasible alternative to conventional BA or DES implantation for treatment of coronary ISR. Further large-scaled, randomized study assessing long-term clinical and angiographic outcomes will be needed.

Hematopoietic stem cell capture and directional differentiation into vascular endothelial cells for metal stent-coated chitosan/hyaluronic acid loading CD133 antibody

A series of metal stents coated with chitosan/hyaluronic acid (CS/HA) loading antibodies by electrostatic self-assembled method were prepared, and the types of cells captured by antibodies and their differentiation in vascular endothelial cells (ECs) evaluated by molecular biology and scanning electron microscope. The results showed that CD133 stent can selectively capture hematopoietic stem cells (HSC),which directionally differentiate into vascular ECs in peripheral blood by (CS/HA) induction, and simultaneously inhibit migration and proliferation of immune cells and vascular smooth muscle cells (MCs). CD34 stent can capture HSC, hematopoietic progenitor cells that differentiate into vascular ECs and immune cells, promoting smooth MCs growth, leading to thrombosis, inflammation, and rejection. CD133 stent can be implanted into miniature pig heart coronary and can repair vascular damage by capturing own HSC, thus contributing to the rapid natural vascular repair, avoiding inflammation and rejection, thrombosis and restenosis. These studies demonstrated that CD133 stent of HSC capture will be an ideal coated metal stent providing a new therapeutic approach for cardiovascular and cerebrovascular disease.

Is there an alternative to systemic anticoagulation, as related to interventional biomedical devices?

To reduce the toxic effects, related clinical problems and complications such as bleeding disorders associated with systemic anticoagulation, it has been hypothesized that by coating the surfaces of medical devices, such as stents, bypass grafts, extracorporeal circuits, guide wires and catheters, there will be a significant reduction in the requirement for systemic anticoagulation or, ideally, it will no longer be necessary. However, current coating processes, even covalent ones, still result in leaching followed by reduced functionality. Alternative anticoagulants and related antiplatelet agents have been used for improvement in terms of reduced restenosis, intimal hyperphasia and device failure. This review focuses on existing heparinization processes, their application in clinical devices and the updated list of alternatives to heparinization in order to obtain a broad overview, it then highlights, in particular, the future possibilities of using heparin and related moieties to tissue engineer scaffolds.

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.

Approaches for prevention of restenosis

Coronary artery disease is characterized by a narrowing (stenosis) of the arteries that supply blood to the tissue of the heart. Continued restriction of blood flow manifests itself as angina and ultimately myocardial infarction (heart attack) for the patient. Heart bypass was once the only treatment for this condition, but over the years percutaneous coronary intervention (PCI) has become an increasingly attractive alternative to medical therapy and surgical revascularization for the treatment of coronary artery disease. A vascular stent is a medical device designed to serve as a temporary or permanent internal scaffold, to maintain or increase the lumen of a blood vessel. Metallic coronary stents were first introduced to prevent arterial dissections and to eliminate vessel recoil and intimal hyperplasia associated with PCI. Further advancement in the treatment of coronary artery disease is the development of drug-eluting stents that dramatically reduce the incidence of in-stent restenosis to less than 5%. Local drug delivery offers the advantages of allowing a relatively high local concentration of drug at the treatment site while minimizing systemic toxic effect. This review describes approaches for prevention of restenosis. It focuses on drugs for prevention of restenosis, bare metal stents, and drug-eluting stents. It also describes recent advances in bioresorbable stents. One of the chapters is dedicated to our novel composite bioresorbable drug-eluting fibers, designed to be used as basic elements in drug-eluting stents.

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.

Comparison of coronary restenosis rates in matched patients with versus without diabetes mellitus

Diabetes mellitus (DM) is an established risk factor for stent restenosis, in part as a result of the smaller vessel dimensions and longer lesions. This study compared the magnitude of acute lumen gain and late lumen loss after elective coronary stent implantation in patients with and without DM using a matched-pair analysis. A total of 133 patients with DM and 192 coronary lesions were included in this analysis. A group of 192 lesions in 182 patients without DM were matched in a pairwise fashion, stratifying for reference diameter, minimal luminal diameter, and lesion length. The binary restenosis rate at the 5-month follow-up angiography was 25% in the DM group and 14% in the non-DM group (p <0.01). Acute angiographic lumen gain (1.47 +/- 0.41 vs 1.56 +/- 0.38 mm, p = 0.03) and late lumen loss (0.64 +/- 0.42 vs 0.55 +/- 0.36 mm, p = 0.02) were significantly different between the DM and non-DM groups. In conclusion, suboptimal acute procedural results and an exaggerated neointimal proliferation contributed by about 50% to the lower net lumen gain in the DM group. Patients with DM had a significantly higher restenosis rate even when matched for preprocedural angiographic lesion dimensions. Mechanistically, inferior procedural results, as well as exaggerated neointimal proliferation, are, quantitatively, equally important in this process.

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.

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.

Drug-eluting stent implantation for treatment of recurrent renal artery in-stent restenosis

Percutaneous renal artery stenting has become the treatment of choice for renal artery stenosis. In-stent restenosis (ISR) still remains a persistent problem. Drug eluting stents have significantly reduced the incidence of ISR in coronary arteries. We report a case in which recurrent renal ISR was successfully treated with paclitaxel-eluting stent implantation, using intravascular ultrasound guidance, with maintained stent patency at 6 months.

Restenosis related to percutaneous coronary intervention has been solved?

Percutaneous coronary intervention (PCI) has become the most important revascularization method in the treatment of coronary artery disease. The major problem in PCI has been renarrowing of the dilated vessel after the procedure (restenosis). The best results in the prevention of restenosis have been obtained by covering the stent with drugs that inhibit cellular growth, thus limiting excessive scar formation inside of the stent. With drug-eluting stents, restenosis has been reduced to one-tenth compared with balloon angioplasty and to one-fourth compared to bare metal stents. Due to drug-eluting stents, PCI is an alternative to bypass surgery. However, restenosis will remain a challenge due to the increased number of procedures and more difficult disease treated with PCI.

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.

Evolution of vascular brachytherapy over time: Data from the RENO-registry analysis

OBJECTIVE

To study the evolution of procedural variations in vascular brachytherapy (VBT) and their relationship to medium-term outcome.

METHODS AND RESULTS

The RENO (European Surveillance Registry with Novoste Beta-Cath) prospectively collected procedural and clinical outcome data on 1098 patients treated with VBT. Patients were divided for this analysis into Group-I, the first 50% registered, and Group-II, the last 50% registered. Shorter 30-mm source trains were more commonly used in Group-I (p<0.001) while longer 40-mm (p=NS) and 60-mm (p<0.001) source trains were more commonly used in Group-II. Mean dwell time for radiation seeds was longer in Group-II compared to Group-I (4.20+/-1.48 min vs. 4.14+/-1.44 min; p<0.05). Mean radiation dose was higher in Group-II (19.73+/-3.33 Gy vs. 17.92+/-2.68 Gy; p<0.001). Cutting balloons were more frequently used in Group-II (p<0.001). There was significant drop in the incidence of geographic miss in Group-II (3.2% vs. 9%; p<0.00005). There were nonsignificant trends towards reduction in angiographic restenosis, target vessel (TV) revascularisation, death and major adverse cardiac events (MACE).

CONCLUSION

There has been a learning curve and evolution of VBT techniques over time. In general, there has been an increase in radiation source length, use of cutting balloons, dwell time and radiation dose. This has resulted in significant reduction of geographic miss and a trend towards improve clinical outcomes. Continued development may result in further improvement in the treatment of patients with in-stent restenosis (ISR).

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.

Drug-eluting stents have made brachytherapy obsolete

PURPOSE OF REVIEW

This manuscript reviews the controversy regarding the role of intravascular brachytherapy in the setting of growing use of drug eluting stents. The utility of intravascular brachytherapy is being rethought in relation to its use after the placement of drug eluting stents. Even with in-stent stenosis, the role of intravascular brachytherapy is decreasing primarily due to the simplicity of placement of drug eluting stents and the complexity of performing intravascular brachytherapy.

RECENT FINDINGS

The impact of drug eluting stents is already decreasing the clinical impact of in-stent stenosis. The published pivotal clinical restenosis rates from both the Pacitaxil (TAXUS IV) and Sirolimus (SIRIUS) drug eluting stents suggests that the need to perform intravascular brachytherapy will be in fewer than one in 20 patients. Recently reported registry data from Europe and the United states demonstrates the equivalence drug eluting stent implantation to intravascular brachytherapy for in-stent stenosis of bare metal stents. The role of intravascular brachytherapy for in-stent stenosis of drug eluting stents is very much in question.

SUMMARY

This manuscript reviews the impact of Drug Eluting Stents in the practice of interventional cardiology and suggests that the need for intravascular brachytherapy will significantly decrease. Whether we will need this therapy at all is very controversial.