Balloon angioplasty for the treatment of coronary in-stent restenosis: immediate results and 6-month angiographic recurrent restenosis rate

Critical evaluation of stents in coronary angioplasty: a systematic review

BACKGROUND

Coronary stents are routinely placed in the treatment and prophylaxis of coronary artery disease (CAD). Current coronary stent designs are prone to developing blockages: in-stent thrombosis (IST) and in-stent re-stenosis (ISR). This is a systematic review of the design of current coronary stent models, their structural properties and their modes of application, with a focus on their associated risks of IST and ISR. The primary aim of this review is to identify the best stent design features for reducing the risk of IST and ISR. To review the three major types of stents used in clinical settings today, determining best and relevant clinical practice by exploring which types and features of offer improved patient outcomes regarding coronary angioplasty. This information can potentially be used to increase the success rate of coronary angioplasty and stent technology in the future taking into account costs and benefits.

METHODS

Scientific databases were searched to find studies concerning stents. After the exclusion criteria were applied, 19 of the 3192 searched literature were included in this review. Studies investigating three major types of stent design were found: bare-metal stents (BMS), drug-eluting stents (DES) and bioresorbable stents (BRS). The number of participants varied between 14 and 1264. On average 77.4% were male, with a mean age of 64 years.

RESULTS

From the findings of these studies, it is clear that DES are superior in reducing the risk of ISR when compared to BMS. Conflicting results do not clarify whether BRS are superior to DES at reducing IST occurrence, although studies into newer BRS technologies show reducing events of IST to 0, creating a promising future for BRS showing them to be non-inferior. Thinner stents were shown to reduce IST rates, due to better re-endothelialisation. Scaffold material has also been shown to play a role with cobalt alloy stents reducing the risk of IST. This study found that thinner stents that release drugs were better at preventing re-blockages. Some dissolvable stents might be better at stopping blood clots blocking the arteries when compared to metal stents. The method and procedure of implanting the stent during coronary angioplasty influences success rate of these stents, meaning stent design is not the only significant factor to consider.

CONCLUSIONS

Positive developments in coronary angioplasty could be made by designing new stents that encompass all the most desirable properties of existing stent technology. Further work is needed to investigate the benefits of BRS in reducing the risk of IST compared to DES, as well as to investigate the effects of different scaffold materials on IST and ISR outcomes.

“Bare Metal” Stent Placement Complications: Interventional Treatment

The rapid implementation of stents in standard practice and expansion of the indication for their utilization also introduced a new problem: in-stent restenosis. Management of patients with restenosis after stent implantation is still considered an important clinical problem. Although balloon angioplasty is still one of the prefered strategies that provide satisfactory results and a low incidence of complication, repeat stenting with “drug eluting” stents or “drug balloon” angioplasty become a very atractive methods of treatment for selected lesions and patients.

A chemical stability study of trimethylsilane plasma nanocoatings for coronary stents

Trimethylsilane (TMS) plasma nanocoatings were deposited onto stainless steel coupons in direct current (DC) and radio frequency (RF) glow discharges and additional NH₃/O₂ plasma treatment to tailor the coating surface properties. The chemical stability of the nanocoatings were evaluated after 12 week storage under dry condition (25 °C) and immersion in simulated body fluid (SBF) at 37 °C. It was found that nanocoatings did not impact surface roughness of underlying stainless steel substrates. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to characterize surface chemistry and compositions. Both DC and RF nanocoatings had Si- and C-rich composition; and the O- and N-contents on the surfaces were substantially increased after NH₃/O₂ plasma treatment. Contact angle measurements showed that DC-TMS nanocoating with NH₃/O₂ treatment generated very hydrophilic surfaces. DC-TMS nanocoatings with NH₃/O₂ treatment showed minimal surface chemistry change after 12 week immersion in SBF. However, nitrogen functionalities on RF-TMS coating with NH₃/O₂ post treatment were not as stable as in DC case. Cell culture studies revealed that the surfaces with DC coating and NH₃/O₂ post treatment demonstrated substantially improved proliferation of endothelial cells over the 12 week storage period at both dry and wet conditions, as compared to other coated surfaces. Therefore, DC nanocoatings with NH₃/O₂ post treatment may be chemically stable for long-term properties, including shelf-life storage and exposure to the bloodstream for coronary stent applications.

In-stent Restenosis

In-stent restenosis (ISR) is the narrowing of a stented coronary artery lesion. The mean time from percutaneous coronary intervention (PCI) to ISR was 12 months with drug-eluting stents (DES) and 6 months with bare metal stents (BMS). ISR typically presents as recurrent angina. The use of DES has significantly reduced the rate of ISR compared with BMS. Predictors of ISR include patient, lesion, and procedural characteristics. Intravascular ultrasound, optical coherence tomography, and fractional flow reserve are important tools for the anatomic and hemodynamic assessment of ISR. Treatment options for ISR include percutaneous coronary intervention with DES.

Intracoronary optical coherence tomography: a review of clinical applications

Optical coherence tomography (OCT) is a light-based technology that provides very high spatial resolution images. OCT has been initially employed as a research tool to investigate plaque morphology and stent strut coverage. The introduction of frequency domain OCT allowing fast image acquisition during a prolonged contrast injection via the guiding catheter has made OCT applicable for guidance of coronary interventions. In this manuscript, the various applications of OCT are reviewed, from assessment of plaque vulnerability and severity to characteristics of unstable lesions and thrombus burden to stent optimization and evaluation of late results.

Long-term effects of ACE inhibitor on vascular remodelling

The long-term pathomorphological changes of the injured vessels under angiotensin-converting-enzyme (ACE) inhibitor are still not known. Therefore, we assessed the alternations of vascular architecture after three-month therapy with ACE inhibitor and identified new target cells for this medication. Carotid arteries of spontaneously hypertensive rats underwent balloon angioplasty. 14 days prior intervention, half of the animals was treated with ACE inhibitor. After three months of vascular trauma, the injured vessels were explored by histomorphology and immunohistochemistry for angiotensin-II receptor (AT1R), dendritic and HSP47+ cells. The neointimal growth decreased significantly only up to 28 days under ACE inhibitor. In contrast, the reductive effect of ACE inhibitor on media area persisted up to three months after intervention. A significant fraction of early neointimal cells was of a dendritic cell type. The relevant portion of these cells showed an expression of AT1R and HSP47. AT1R was present in 70% and HSP47 in 18% of all early neointimal cells in both groups. ACE inhibitor may at least temporarily diminish remodelling processes in injured vessels. The detection of AT1R on dendritic cells identifies these cells as important targets for therapeutic strategies involving modulation of the renin-angiotensin system.

Feasibility of in vivo intravascular photoacoustic imaging using integrated ultrasound and photoacoustic imaging catheter

Pilot studies of in vivo combined intravascular ultrasound (IVUS) and intravascular photoacoustic (IVPA) imaging are reported. A recently introduced prototype of an integrated IVUS/IVPA imaging catheter consisting of a single-element ultrasound transducer and a light delivery system based on a single optical fiber was adapted and used for in vivo imaging of a coronary stent deployed in a rabbit's thoracic aorta in the presence of luminal blood. The results suggest that in vivo IVUS/IVPA imaging is feasible using the integrated IVUS/IVPA imaging catheter. The challenges of in vivo combined IVUS/IVPA imaging are discussed, and further improvements on the design of the catheter and the clinical imaging system are proposed.

In-stent restenosis

The introduction of coronary stents marked a major turning point in the practice of interventional cardiology. Whereas the efficacy of balloon angioplasty was challenged both by immediate mechanical complications and by a high incidence of restenosis, coronary stents offered cardiologists a means by which to not only augment immediate procedural success, but also to reduce the incidence of restenosis following coronary intervention. However, despite technological advances and an improved understanding of the restenotic process, the overall rate of in-stent restenosis following bare metal stent implantation remains high. Although the introduction of drug-eluting stents has further reduced the incidence of restenosis, the "real-world" application of drug-eluting stents in increasingly complex lesion and patient subsets has given way to the even greater clinical challenge of managing drug-eluting stent restenosis. Although the standard treatment of bare metal stent restenosis typically involves placement of a drug-eluting stent, the optimal therapeutic approach to drug-eluting stent restenosis remains less defined. The issue of in-stent restenosis (especially following implantation of a drug-eluting stent) remains a clinical challenge, and investigation into therapeutic options remains ongoing. As technology evolves, such investigation will likely incorporate novel approaches including drug-coated balloons novel stent designs.

Long-term angiographic follow-up after successful repeat balloon angioplasty for in-stent restenosis

BACKGROUND

Coronary stent implantation is associated with improved angiographic short-term and mid-term clinical outcome. However, restenosis rate still remains between 20 and 30%.

HYPOTHESIS

The purpose of the study, performed as a prospective angiographic follow-up to detect restenosis, was to evaluate the immediate and the 6-month angiographic results of repeat balloon angioplasty for in-stent restenosis.

METHODS

From April 1996 to September 1997, 335 stenting procedures performed in 327 patients underwent prospectively 6-month control angiography. Of the 96 lesions that showed in-stent restenosis (> 50% diameter stenosis) (29%), 72 underwent balloon angioplasty.

RESULTS

The primary success rate was 100%. Follow-up angiogram at a mean of 6.9 +/- 2.4 months was obtained in 54 patients. Recurrent restenosis was observed in 24 of the 55 stents (44%). Repeat intervention for diffuse and body location in-stent restenosis before repeat intervention was associated with significantly higher rates of recurrent restenosis (p < 0.001 and p < 0.05, respectively). Of the 19 patients who underwent further balloon angioplasty (100% success rate), coronary angiography was performed in 18 (95%) at a mean of 8.2 +/- 2.0 months and showed recurrent restenosis in 12 patients (67%). Further repeat intervention for diffuse and severe in-stent restenosis before the second repeat intervention was associated with significantly higher rates of further recurrent restenosis (p < 0.05 and p < 0.005, respectively).

CONCLUSIONS

Although balloon angioplasty can be safely, successfully, and repeatedly performed after stent restenosis, it carries a progressively high recurrence of angiographic restenosis rate during repeat 6-month follow-ups. The subgroup of patients with diffuse, severe, and/or body location in-stent restenosis proved to be at higher risk of recurrent 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.

Neointimal progression and luminal narrowing in sirolimus-eluting stent treatment for bare metal in-stent restenosis: a quantitative intravascular ultrasound analysis

BACKGROUND

Recurrent restenosis may occur after drug-eluting stent implantation for in-stent restenosis (ISR) of bare metal stents (BMSs), especially in areas involving drug-eluting stent gaps.

METHODS

To investigate the details of neointimal progression and luminal narrowing after the treatment of ISR using sirolimus-eluting stents (SESs), serial intravascular ultrasound analysis was performed in 65 patients with ISR at postintervention and at 6-month follow-up. The total stented segment was categorized into 3 compartments: new SES (N), new SES and old BMS overlap (N/O), and old BMS (O). In each of the 190 compartments, serial intravascular ultrasound parameters were analyzed at the cross section of the maximum change in neointimal area (delta neointimal area) from postintervention to follow-up or the minimum lumen area at follow-up if delta neointimal area was 0. Minimum lumen area in each compartment was also investigated serially.

RESULTS

At postintervention, lumen area was the smallest in compartment N/O (N 5.8 +/- 1.5, N/O 5.1 +/- 1.3, O 6.0 +/- 1.4 mm2, P = .005). Not only the average of maximum delta neointimal area (N 0.2 +/- 0.4, N/O 0.2 +/- 0.4, O 0.8 +/- 1.0 mm2, P < .0001) but also the frequency of minimum lumen area decreasing from > or = 4.0 mm2 at postintervention to < 4.0 mm2 at follow-up (N 4.0%, N/O 5.1%, O 23.5%, P = .012) was the largest in compartment O.

CONCLUSIONS

Neointimal progression and consequent luminal narrowing tend to occur where BMS is uncovered with SES in treatment of ISR, even in the absence of an obvious stenosis at postintervention.

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.

Effectiveness and safety of sirolimus stent implantation for coronary in-stent restenosis: the TRUE (Tuscany Registry of Sirolimus for Unselected In-Stent Restenosis) Registry

OBJECTIVES

This study sought to evaluate the effectiveness and safety of the sirolimus-eluting stent in the treatment of in-stent restenosis (ISR) in consecutive unselected patients undergoing coronary intervention in a real-world scenario.

BACKGROUND

Restenosis after bare metal stenting is characterized by a high rate of re-restenosis once treated with repeated percutaneous coronary intervention.

METHODS

The study was designed as a prospective two-center registry. We enrolled 244 patients with ISR in a native coronary artery or saphenous vein graft who had clinical indication for repeat intervention.

RESULTS

Sirolimus stent implantation was successful in all lesions. At 9-month follow-up, death occurred in 4 (1.6%) patients, myocardial infarction in 4 (1.6%), and ischemia-driven target lesion revascularization (TLR) in 12 (4.9%), for a cumulative event-free survival of 227 (93%). Although 9-month follow-up angiography was planned in all patients, only 150 (62%) patients completed it, and restenosis was present in 13 (8.7%) patients. Diabetes and non-ST-segment elevation acute coronary syndrome at presentation were the only independent predictors of freedom from ischemia-driven TLR and major adverse cardiac events.

CONCLUSIONS

Sirolimus stent implantation for the treatment of ISR is effective and safe. In diabetic patients and in those with acute coronary syndrome, the higher rate of recurrence requires further evaluation.

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.

Comparison of sirolimus versus paclitaxel eluting stents for treatment of coronary in-stent restenosis

In patients with in-stent restenosis (ISR) inside bare metal stents, drug-eluting stents reduce the recurrence of restenosis compared with balloon angioplasty. However, few data are available about this therapeutic modality in the case of diffuse restenosis. The aim of this study was to evaluate the immediate and mid-term outcome of sirolimus- and paclitaxel-eluting stent implantation in diffuse ISR and determine the predictors of clinical and angiographic restenosis recurrence. A series of 161 consecutive patients with 194 diffuse ISR lesions (>10 mm) treated with drug-eluting stent implantation were evaluated. Major adverse cardiac events were defined as death, myocardial infarction, and the need for target lesion revascularization. During a mean follow-up of 8.2 +/- 3.4 months, the cumulative incidence of major adverse cardiac events was 19% in the SES group and 24% in the PES group (p = 0.56). Angiographic follow-up was performed in 80% of the lesions. The overall restenosis rate was 22% and was not significantly different between lesions treated with sirolimus-eluting (20%) or paclitaxel-eluting (25%, p = 0.55) stents. The incidence of restenosis was higher in diabetics (32%) than in nondiabetics (16%, odds ratio 2.5, 95% confidence interval 1.1 to 5.5, p = 0.02). By multivariate analysis, diabetes was confirmed to be the only independent predictor of recurrent restenosis (odds ratio 3.53, 95% confidence interval 1.39 to 9.02, p = 0.008). In conclusion, drug-eluting stent implantation for diffuse ISR is associated with acceptable clinical and angiographic results. The association of diffuse restenosis and diabetes mellitus is an unfavorable condition leading to a high risk of recurrence.

Value of the American College of Cardiology/American Heart Association angiographic classification of coronary lesion morphology in patients with in-stent restenosis. Insights from the Restenosis Intra-stent Balloon angioplasty versus elective Stenting (RIBS) randomized trial

BACKGROUND

The implications of the American College of Cardiology/American Heart Association (ACC/AHA) lesion classification in patients with in-stent restenosis (ISR) are unknown.

METHODS

Four hundred fifty patients included in the RIBS randomized study were analyzed. A centralized core laboratory assessed ISR classifications including ACC/AHA, the classification of Mehran et al (Circulation 1999;100:1872-8), diffuse/focal, and a new quantitative ISR index (lesion length/stent length). Logistic regression models were constructed for prespecified outcome measures including (1) unsatisfactory acute results and (2) recurrent restenosis rate.

RESULTS

Complex (B2/C) lesions (78%) more frequently obtained unsatisfactory acute results (20% vs 8%, P = .007), smaller minimal lumen diameter after the procedure (2.45 +/- 0.5 vs 2.73 +/- 0.5 mm, P = .001) and at follow-up (1.48 +/- 0.8 vs 1.94 +/- 0.8 mm, P = .0001), and had a higher restenosis rate (43 vs 24%, P = .001) than simple (A/B1) lesions. On logistic regression analysis, all classification schemes were useful to predict unsatisfactory initial results (area under the curve: 0.63, 0.61, 0.59, and 0.62) and recurrent restenosis (area under the curve: 0.60, 0.64, 0.61, and 0.63). The predictive ability of these schemes persisted despite adjustment for potential confounders. Although the ACC/AHA classification was a better predictor of acute results, the classification of Mehran was superior to predict restenosis.

CONCLUSIONS

The ACC/AHA classification provides a useful tool to determine acute procedural results and the long-term angiographic outcome of patients with ISR.

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.

Effectiveness of a Sirolimus-Eluting Stent (Cypher ) for Diffuse In-Stent Restenosis Inside a Bare Metal Stent

We estimated the benefit of a sirolimus-eluting stent (SES, Cypher) for diffuse (> 10 mm) in-stent restenosis (ISR) inside bare metal stents (BMS) because the feasibility of the SES was not confirmed after its recent approval in Japan. Clinical and angiographic outcomes after SES implantation to 93 diffuse ISR were compared with those of 3 groups treated by plain old balloon angioplasty (POBA, (n = 54)), cutting balloon angioplasty (CB, (n = 24)), and BMS (n = 41) in a series of 153 patients whose follow-up quantitative coronary angiography (QCA) evaluated 3-9 months after the treatments was obtained from January 2003 through December 2005. For 33 lesions in the SES group, 12-month follow-up QCA results were obtained and compared with those at 6 months. Ticlopidine (200 mg/day) was prescribed for at least 12 weeks after SES implantation and for 2 weeks after BMS in addition to aspirin (81-100 mg/day). Patient characteristics and the characteristics of previous implanted BMS in the SES group were not significantly different from those in the other groups. Death from cardiac causes and nonfatal myocardial infarction did not occur in any group. Stent thrombosis was not observed in the BMS and SES groups. The incidence of repeat target lesion revascularization (re-TLR) in the SES group (3.23%) was significantly lower compared with that of the POBA (37.0%), CB (25.0%), and BMS (29.3%) groups (P < 0.001, respectively). Late loss in the SES group (0.44 +/- 0.41 mm) was significantly smaller than that in the BMS group (1.34 +/- 0.74 mm) (P < 0.05). The rate of recurrent ISR (re-ISR) in SES (5.38%) was significantly lower than that in POBA (46.3%), CB (41.7%), and BMS (46.3%) (P < 0.001, respectively). The QCA variables at 6 months in the SES group were not significantly different from those at 12 months. Thus, SES implantation for diffuse ISR was far superior since it markedly reduced the incidence of re-TLR with re-ISR at up to 6-months follow-up. In addition, this angiographic patency after SES implantation continued until 12 months.

Localized delivery of nitric oxide from hydrogels inhibits neointima formation in a rat carotid balloon injury model

Using novel nitric oxide (NO)-generating polymeric hydrogels that can be rapidly photopolymerized in situ, we can deliver NO locally at the site of vascular injury. Depending on material design, these poly(ethylene glycol) (PEG)-based hydrogels can generate NO for up to 50 d. This study demonstrates the ability of nitric oxide-generating hydrogels (PEG-Cys-NO) to influence key components of the restenosis cascade both in vitro and in vivo. PEG-Cys-NO hydrogels inhibited smooth muscle cell proliferation, increased endothelial cell proliferation, and inhibited platelet adhesion in vitro. Moreover, in vivo, PEG-Cys-NO hydrogels inhibited intimal thickening in a rat carotid balloon injury model. The perivascular application of NO-generating polymers post-injury reduced neointima formation at 14 d by approximately 80% compared to controls (intimal area/medial area (I/M): PEG-Cys-NO=0.20+/-0.17, control=0.84+/-0.19, p<0.00002; intimal thickness: PEG-Cys-NO=12+/-10 microm, control=60+/-18 microm, p<0.00002). Treatment with the PEG-Cys-NO hydrogels caused a significant decrease in the per cent of proliferating cell nuclear antigen positive medial cells (29+/-5%) at 4 d as compared to treatment with the control hydrogels (51+/-1%, p<0.02). Additionally, vessel re-endothelialization at 14 d was slightly enhanced in the presence of the NO-generating hydrogels. These data indicate that localized delivery of NO from these hydrogels can significantly inhibit neointima formation in a rat carotid balloon injury model and suggest that these materials may be useful in preventing restenosis.

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.

[Prevention of in-stent restenosis: towards an in situ treatment?]

The use of intracoronary stents represent a major breakthrough in the armamentarium of interventional cardiology. Stents reduce significantly the incidence of recurrent stenosis (in-stent restenosis) via an improved post-procedure luminal diameter and an abrogation of the constrictive remodeling of the arterial wall. However, stent-related arterial injury results in intense proliferative and inflammatory responses and severe intimal hyperplasia, which, in 20% to 40% of the patients, may end up with clinically significant in-stent restenosis. Efficient prevention of in-stent restenosis has yet to be found. Systemic treatments have failed because they don't take into account the specific physiopathology and, most importantly, the focal nature of in-stent intimal hyperplasia. Hence, local prevention appears to be a straightforward approach to the unsolved issue of in-stent restenosis. In situ beta- or gamma-irradiation (brachytherapy) has received much attention as a curative treatment of in-stent restenosis but is not indicated for prevention. In contrast, drug-releasing stents have been tested in experimental models and have already provided very promising results in randomized clinical trials. Most of clinical studies have been performed with the antiproliferative agents sirolimus and paclitaxel, but other agents are under scrutiny. In addition, important research is carried out, in which the efficacy of antiproliferative genes is investigated. Clearly, drug-releasing stents are on the verge of profoundly modifying our practice of interventional cardiology. However, several questions remain unanswered as regard to the long term efficacy/toxicity and the cost-effectiveness of this new approach.

[Treatment of intrastent restenosis]

In-stent restenosis (ISR) remains an important limitation after stent implantation occurring in 20-30% of patients. Different techniques and treatments have been evaluated in this setting. Repeat balloon angioplasty alone has been rapidly followed by ablative techniques such as laser, rotational atherectomy or implantation of a second stent within the stent. Cutting balloon represents another alternative technique. None of these techniques has proven its superiority over plain balloon angioplasty alone. Brachytherapy is the only effective treatment for ISR by significantly decreasing recurrent restenosis rate at follow-up. However, its use is limited by cost and infrastructure associated with the risk of late thrombosis requiring prolonged antiplatelet therapy. Surgical treatment can be proposed in recurrent ISR as well as medical therapy alone in pauci-symptomatic patients. New drug-eluting stents are under evaluation in this indication.

Les facteurs prédictifs de la resténose : quels changements avec les stents « actifs » ?

For many years, restenosis was the major limiting factor of coronary angioplasty, even since the systematic use of stents. Numerous scientific publications have aimed to define the predictive factors of this phenomenon. Factors such as diabetes, the size of the treated artery, the use of stents or not, the length of the lesion, lesion located on the proximal left anterior descending artery, the degree of residual stenosis post-angioplasty (assessed by angiography or by intravascular ultrasound) have all been evoked as being classically related to restenosis. However, our perception of the restenosis phenomenon has been dramatically changed by the demonstration of the efficacy and security of active stents. Even in so-called "at risk" populations, the use of active stents is rarely followed by restenosis. In this way, the classic risk factors for restenosis have now become arguments in favour of the implantation of an active stent. As long as budgetary constraints limit the use of active stents to patients said to be "at risk of restenosis", this population, quite paradoxically, will have a more favourable outcome than so-called "low risk" patients, in whom "ordinary" non-active stents will continue to be used.

Non–Polymer-Based Paclitaxel-Coated Coronary Stents for the Treatment of Patients With De Novo Coronary Lesions

BACKGROUND

Paclitaxel, a microtubule-stabilizing compound with potent antitumor activity, has been shown to inhibit smooth muscle cell proliferation and migration. The DELIVER trial was a prospective, randomized, blinded, multicenter clinical evaluation of the non-polymer-based paclitaxel-coated ACHIEVE stent compared with the stainless steel Multi-Link (ML) PENTA stent.

METHODS AND RESULTS

A total of 1043 patients with focal de novo coronary lesions, <25 mm in length, in 2.5- to 4.0-mm vessels were randomized (ACHIEVE n=524; ML PENTA n=519). Angiographic follow-up was performed in a subset of 442 patients (ACHIEVE n=228; ML PENTA n=214). Prespecified end points were a 40% reduction in target-vessel failure at 9 months (primary clinical end point) and a 50% reduction in binary restenosis at 8 months (major secondary end point). Baseline clinical characteristics were comparable between the groups. Patients in ACHIEVE had more type C lesions and a larger reference diameter. At follow-up, stent late loss was 0.81 versus 0.98 mm (P=0.003), stent binary restenosis was 14.9% versus 20.6% (P=0.076), and target-vessel failure was 11.9% versus 14.5% (P=0.12) for ACHIEVE and ML PENTA, respectively.

CONCLUSIONS

The ACHIEVE paclitaxel-coated stent decreased neointimal proliferation compared with the bare-metal PENTA stent; however, this reduction was insufficient to meet the prespecified primary end point of target-vessel failure and the secondary end point of binary restenosis.

Analysis of nonintervention strategy for in-stent restenosis in Pauci- or asymptomatic patients

Between January 1996 and May 2000, we retrospectively identified 66 patients (61 +/- 11 years) with in-stent restenosis who did not undergo percutaneous coronary intervention and/or bypass surgery and were maintained on medical treatment alone. In-stent restenosis was diffuse or proliferative in 86% of these patients. At 33 +/- 11 months, 2 patients died, none developed myocardial infarction, and 6 (9%) had target lesion revascularization only (repeat percutaneous transluminal coronary angioplasty). Medical treatment alone was associated with a good long-term clinical follow-up in selected patients with significant documented in-stent restenosis.

Drug-eluting stents: new era and new concerns

At present there is much excitement about drug-eluting stents, which hold promise for the treatment of coronary artery disease. This ingenious therapy involves coating the outside of a standard coronary stent with a thin polymer containing medication that can prevent scarring at the site of coronary intervention. Early trials with sirolimus coated stents showed that they might prevent coronary artery restenosis, but later studies, involving more complex coronary lesions, did not show a complete absence of restenosis. Recent studies have demonstrated the long term cost effectiveness of drug-eluting stents as they have reduced the need for revascularisation procedures. At present there are few data on the safety and effectiveness of stents over follow up periods exceeding two years, and data obtained from animal models of stenting might not be completely applicable to humans. There are concerns that drug-eluting stents might delay, rather than inhibit, restenosis. Also there is concern regarding the inflammation caused by the polymer substrate. This article reviews the present data on drug-eluting stents and their benefits, shortcomings, and concerns.

Cutting balloon versus conventional balloon angioplasty for the treatment of in-stent restenosis: results of the restenosis cutting balloon evaluation trial (RESCUT)

OBJECTIVES

The aim of this trial was to compare cutting balloon angioplasty (CBA) with conventional balloon angioplasty (i.e., percutaneous transluminal coronary angioplasty [PTCA]) for the treatment of patients with coronary in-stent restenosis (ISR).

BACKGROUND

Retrospective studies suggest CBA might be superior to conventional PTCA in the treatment of ISR.

METHODS

The Restenosis Cutting Balloon Evaluation Trial (RESCUT) is a multicenter, randomized, prospective European trial including 428 patients with all types of ISR (e.g., focal, multifocal, diffuse, proliferative).

RESULTS

In both groups, the majority of ISR lesions were shorter than 20 mm. The length of restenotic stents was similar (CBA: 18.6 +/- 9.7 mm; PTCA: 18.3 +/- 8.7 mm). The number of balloons used to treat ISR was lower in the CBA group: only one balloon was used in 82.3% of CBA cases, compared with 75% of PTCA procedures (p = 0.03). Balloon slippage was less frequent in the CBA group (CBA 6.5%, PTCA 25%; p < 0.01). There was a trend toward a lower need for additional stenting in the CBA group (CBA 3.9%, PTCA 8.0%; p = 0.07). At seven-month angiographic follow-up, the binary restenosis rate was not different between the groups (CBA 29.8%, PTCA 31.4%; p = 0.82), with a similar pattern of recurrent restenosis. Clinical events at seven months were also similar.

CONCLUSIONS

Cutting balloon angioplasty did not reduce recurrent ISR and major adverse cardiac events, as compared with conventional PTCA. However, CBA was associated with some procedural advantages, such as use of fewer balloons, less requirement for additional stenting, and a lower incidence of balloon slippage.

Predictors of 32P beta brachytherapy failure in patients with high-risk in-stent restenosis

BACKGROUND

The effectiveness of coronary radiation therapy for the treatment of in-stent restenosis (ISR) has been established in several randomized clinical trials. The efficacy of this treatment in the general population is less well established.

METHODS AND MATERIALS

We report our experience in 118 consecutive patients with nonselected high-risk ISR who had undergone successful percutaneous coronary intervention and brachytherapy with (32)P beta-irradiation and who were prospectively enrolled in a quantitative angiographic and clinical follow-up protocol at 7 months after the index procedure. The aim of this study was to investigate the independent predictor of angiographic restenosis after (32)P brachytherapy treatment.

RESULTS

Of the patients, 28.8% were diabetics. The mean lesion and mean radiated lengths were, respectively, 30.1 +/- 17.2 and 43.8 +/- 16.9 mm. The ISR pattern was diffuse in 96% of the treated lesions; in particular, 22.1% presented an occlusive pattern and 37.1% a proliferative pattern. At follow-up angiographic, restenosis and major adverse cardiac events (MACE) rates were, respectively, 20.8% and 29.6%. The univariate predictors of angiographic restenosis were procedural geographic miss, pattern IV ISR, manual pullback maneuver of the radiation source, preprocedural lesion percentage stenosis and preprocedural lesion MLD. At logistic regression analysis, only geographic miss and pattern IV ISR were independent predictors of post intracoronary radiation therapy (IRT) angiographic restenosis.

CONCLUSION

These data indicate that 7-month angiographic restenosis after (32)P IRT in complex patients with ISR is not a frequent event and is predicted mainly by an occlusive lesion at baseline and by procedural geographical miss.

Stent restenosis and the use of drug-eluting stents in patients with diabetes mellitus

Stents have become the technique of choice for percutaneous revascularization, but in-stent restenosis has remained a clinical challenge. This brief article summarizes the incidence, patterns, and proposed mechanisms of restenosis and outlines its contemporary management with specific focus on the diabetic patient. It includes a synopsis of the strategy of drug-eluting stents, which is the most recent and major advance in percutaneous coronary intervention.

Percutaneous treatment of focal vs. diffuse in-stent restenosis: A prospective randomized comparison of conventional therapies

Few randomized studies compare outcomes for focal vs. diffuse in-stent restenosis (ISR) using conventional treatments. The purpose of this study was to compare the rates of major adverse cardiac events (MACEs) for focal vs. diffuse ISR using conventional techniques. One hundred thirteen patients with ISR were prospectively classified as focal (< 10 mm) or diffuse (> 10 mm). Focal ISR was randomized to balloon angioplasty (n = 29) or restenting (n = 29) and diffuse ISR randomized to rotational atherectomy (n = 30) or restenting (n = 25). At 9 months, patients with focal ISR had higher survival free of MACEs than patients with diffuse ISR (86% vs. 63%; P < 0.005), with no difference between techniques. Only the presence of diffuse ISR was an independent predictor of MACE at 9 months. Thus, focal ISR has a low rate of MACE compared to diffuse ISR, which carries a high event rate regardless of treatment employed.

Usefulness of the angiographic pattern of in-stent restenosis in predicting the success of gamma vascular brachytherapy

The prognostic role of the angiographic pattern of in-stent restenosis after gamma vascular brachytherapy was assessed from a pooled data set of 4 clinical trials comprising 295 irradiated patients with matched baseline and follow-up angiograms. The binary angiographic restenosis rate increased with worsening in-stent restenosis patterns; however, target lesion revascularization and major adverse cardiac event rates increased for focal, diffuse, and proliferative patterns of in-stent restenosis but not for total occlusions.

Arterial remodeling patterns before intervention predict diffuse in-stent restenosis

OBJECTIVES

The aim of this retrospective study was to determine the predictors of diffuse in-stent restenosis (ISR) among the lesions causing the first ISR by intravascular ultrasound (IVUS) studies.

BACKGROUND

Although some predictors of diffuse ISR have been reported, parameters on IVUS relating to diffuse ISR are not well characterized.

METHODS

We classified 52 ISR lesions that had undergone successful stent implantation and led to restenosis into two types--focal and diffuse ISR--using quantitative coronary angiography. Restenosis was defined as > or =50% diameter stenosis, and diffuse ISR as lesion length > or =10 mm at follow-up. The remodeling index (RI) was defined as the vessel area at the target lesion divided by that of averaged reference segments.

RESULTS

There were no significant differences in patient, angiographic, and procedural characteristics between the focal (n = 25) and diffuse (n = 27) ISR groups. Baseline RI was significantly greater in the diffuse ISR group (1.03 +/- 0.18 vs. 0.88 +/- 0.24, p = 0.0159). Negative remodeling, defined as RI <0.9, was detected in 60% of the focal ISR group and in only 26% of the diffuse ISR group. By logistic regression analysis, baseline RI was the only independent predictor of diffuse ISR (p = 0.0341). Moreover, volumetric analyses revealed that lesions developing into diffuse ISR had less capacity to compensate for further plaque growth.

CONCLUSIONS

Among the first ISR lesions, baseline positive remodeling was the most powerful predictor of diffuse ISR. Measuring pre-interventional arterial remodeling patterns by IVUS may be helpful to stratify lesions at higher risk.

Vascular brachytherapy using a beta emitter source in diabetic patients with in-stent restenosis: angiographic and clinical outcomes

PURPOSE

The management of diabetic patients with restenosis after percutaneous coronary intervention remains a significant challenge. Diabetic patients remain at significant risk of restenosis despite stent implantation. This retrospective analysis was performed to determine the extent to which vascular brachytherapy improves late clinical and angiographic outcomes in diabetic patients compared to conventional therapy and compared to patients' nondiabetic counterparts.

METHODS

Pooled data from two studies (START [Stents and Radiation Trial] and START-40 trials) of patients (204 diabetic, 477 nondiabetic) receiving vascular brachytherapy (VBT) with a (90)Sr/(90)Y source after conventional percutaneous coronary intervention for in-stent restenosis comprise the study population. The radiation delivery system used in both studies was the Beta-Cath system. The prescribed dose at 2 mm from the centerline of the source axis was 18.4 Gy or 23 Gy, depending on vessel diameter. The reference vessel diameter, minimal lumen diameter, and percent diameter stenosis were measured before the intervention, at the conclusion of the procedure, and at the 8-month follow-up examination. The Breslow-Day test was used to formally assess the similarity of treatment effect between diabetic and nondiabetic patients.

RESULTS

Target lesion and target vessel revascularization rates and angiographic restenosis rates in diabetic and nondiabetic patients treated with beta radiation or placebo were analyzed. Diabetic patients were more likely to have longer and more complex coronary lesions. In-hospital outcomes in diabetic and nondiabetic patients were similar, irrespective of treatment status. At 8 months, patients treated with beta radiation exhibited less target lesion revascularization (diabetic: 10.9% vs. 22.7%, p = 0.02; nondiabetic: 12.8% vs. 22.3%, p = 0.007) and less target vessel revascularization (diabetic: 14.7% vs. 25.3%, p = 0.06; nondiabetic: 16.6% vs. 23.6%, p = 0.06) compared to placebo. In-stent binary angiographic restenosis was lower in irradiated patients (diabetic: 19.4% vs. 37.3% for placebo, p = 0.01; nondiabetic: 12.9% vs. 43% for placebo, p < 0.001). However, restenosis beyond the stent site reduced the impact of VBT, regardless of diabetic status. The magnitude of the treatment effect for target lesion and target vessel revascularization rates was similar between diabetic and nondiabetic patients.

CONCLUSIONS

Previously published institutional experiences have suggested that diabetic patients benefit from the use of VBT in the management of in-stent restenosis. This analysis now provides direct evidence to support the role of beta radiation VBT in this patient population. Diabetic patients undergoing this therapy are just as likely to benefit from it as their nondiabetic counterparts.

Effectiveness of treatment of in-stent restenosis with an 8-French compatible atherectomy catheter

The study reports the results of directional atherectomy with an 8Fr guiding catheter-compatible atherectomy catheter in a series of 31 in-stent restenotic lesions. This preliminary experience indicates a favorable safety profile, with events limited to non-Q-wave myocardial infarction occurring in 3.6% of patients. The secondary end point regarding the incidence of angiographic restenosis at 6 months showed a high restenosis rate (65%).

A randomized comparison of repeat stenting with balloon angioplasty in patients with in-stent restenosis

OBJECTIVES

This randomized trial compared repeat stenting with balloon angioplasty (BA) in patients with in-stent restenosis (ISR).

BACKGROUND

Stent restenosis constitutes a therapeutic challenge. Repeat coronary interventions are currently used in this setting, but the recurrence risk remains high.

METHODS

We randomly assigned 450 patients with ISR to elective stent implantation (224 patients) or conventional BA (226 patients). Primary end point was recurrent restenosis rate at six months. Secondary end points included minimal lumen diameter (MLD), prespecified subgroup analyses, and a composite of major adverse events.

RESULTS

Procedural success was similar in both groups, but in-hospital complications were more frequent in the balloon group. After the procedure MLD was larger in the stent group (2.77 +/- 0.4 vs. 2.25 +/- 0.5 mm, p < 0.001). At follow-up, MLD was larger after stenting when the in-lesion site was considered (1.69 +/- 0.8 vs. 1.54 +/- 0.7 mm, p = 0.046). However, the binary restenosis rate (38% stent group, 39% balloon group) was similar with the two strategies. One-year event-free survival (follow-up 100%) was also similar in both groups (77% stent vs. 71% balloon, p = 0.19). Nevertheless, in the prespecified subgroup of patients with large vessels (> or =3 mm) the restenosis rate (27% vs. 49%, p = 0.007) and the event-free survival (84% vs. 62%, p = 0.002) were better after repeat stenting.

CONCLUSIONS

In patients with ISR, repeat coronary stenting provided better initial angiographic results but failed to improve restenosis rate and clinical outcome when compared with BA. However, in patients with large vessels coronary stenting improved the long-term clinical and angiographic outcome.

Targeting the cell cycle machinery for the treatment of cardiovascular disease

Cardiovascular disease represents a major clinical problem affecting a significant proportion of the world's population and remains the main cause of death in the UK. The majority of therapies currently available for the treatment of cardiovascular disease do not cure the problem but merely treat the symptoms. Furthermore, many cardioactive drugs have serious side effects and have narrow therapeutic windows that can limit their usefulness in the clinic. Thus, the development of more selective and highly effective therapeutic strategies that could cure specific cardiovascular diseases would be of enormous benefit both to the patient and to those countries where healthcare systems are responsible for an increasing number of patients. In this review, we discuss the evidence that suggests that targeting the cell cycle machinery in cardiovascular cells provides a novel strategy for the treatment of certain cardiovascular diseases. Those cell cycle molecules that are important for regulating terminal differentiation of cardiac myocytes and whether they can be targeted to reinitiate cell division and myocardial repair will be discussed as will the molecules that control vascular smooth muscle cell (VSMC) and endothelial cell proliferation in disorders such as atherosclerosis and restenosis. The main approaches currently used to target the cell cycle machinery in cardiovascular disease have employed gene therapy techniques. We will overview the different methods and routes of gene delivery to the cardiovascular system and describe possible future drug therapies for these disorders. Although the majority of the published data comes from animal studies, there are several instances where potential therapies have moved into the clinical setting with promising results.

Intracoronary radiation therapy improves the clinical and angiographic outcomes of diffuse in-stent restenotic lesions: results of the Washington Radiation for In-Stent Restenosis Trial for Long Lesions (Long WRIST) Studies

BACKGROUND

The Washington Radiation for In-Stent Restenosis Trial for long lesions (Long WRIST) was designed to determine the safety and efficacy of vascular brachytherapy for the treatment of diffuse in-stent restenosis.

METHODS AND RESULTS

A total of 120 patients with diffuse in-stent restenosis in native coronary arteries (lesion length, 36 to 80 mm) were randomized for either radiation with 192Ir with 15 Gy at 2 mm from the source axis or placebo. After enrollment, 120 additional patients with the same inclusion criteria were treated with 192Ir with 18 Gy and included in the Long WRIST High Dose registry. Antiplatelet therapy was initially prescribed for 1 month and was extended to 6 months in the last 60 patients of the Long WRIST High Dose registry. At 6 months, the binary angiographic restenosis rate was 73%, 45%, and 38% in the placebo, 15 Gy, and 18 Gy radiated groups, respectively (P<0.05). At 1 year, the primary clinical end point of major cardiac events was 63% in the placebo group and 42% in the radiated group with 15 Gy (P<0.05). The major cardiac event rate was further reduced with 18 Gy (22%; P<0.05 versus 15 Gy). Late thrombosis was 12%, 15%, and 9% in the placebo group, 15 Gy group with 1 month of antiplatelet therapy, and 18 Gy group with 6 months of antiplatelet therapy, respectively.

CONCLUSIONS

Vascular brachytherapy with 192Ir is safe and reduces the rate of recurrent restenosis in diffuse in-stent restenosis. The efficacy of vascular brachytherapy on angiographic and clinical outcomes is enhanced with a radiation dose of 18 Gy and prolonged antiplatelet therapy.

Intracoronary beta-brachytherapy in chronic total occlusions: a subgroup analysis from the RENO registry

Conventional interventional therapy has been less rewarding in chronic total occlusion (CTO). Brachytherapy by its antiproliferative and positive remodeling effect may be more efficacious. Forty-six centers registered 1,098 consecutive patients undergoing brachytherapy with the BetaCath system. Of these, 78 patients had 82 lesions (CTO) at presentation-the study population. With 67% in-stent CTO, 8% graft CTO, 4% recurrent CTO, long lesions (27.6 +/- 20.9 mm), and 31% diabetes, the cohort had high risk for recurrence. The in-hospital event rate was 1.3%. Six-month follow-up revealed 1.3% death, 5.1% myocardial infarction, 21.8% target vessel revascularization, 77.8% improved angina, 34.5% binary restenosis, 12.7% reocclusion, and 10.3% late thrombosis. The results were comparable to all other patients in the registry, although late thrombosis rate was higher in the CTO group (10.3% vs. 5.0%; P = 0.047). In the in-stent CTO subgroup (n = 52; 66.7%), there was no in-hospital event, no follow-up death or myocardial infarction, restenosis in 35.1%, and reocclusion in 10.8% of patients. In comparison, death or myocardial infarction was significantly higher in de novo CTO subgroup (P = 0.005). Compared to all other in-stent restenosis patients in the registry, the patients with in-stent CTO had similar clinical and angiographic event rate. Thus, beta-brachytherapy was safe, feasible, and effective in this broad population of high-risk patients with CTO presenting in day-to-day practice. It was particularly effective in in-stent CTO, where conventional interventional strategies are disappointing.

Enhanced extracellular matrix accumulation in restenosis of coronary arteries after stent deployment

OBJECTIVES

The goal of this study was to evaluate the cellular and extracellular composition of human coronary arterial in-stent restenosis after various periods of time following stent deployment.

BACKGROUND

Neointimal in-growth rather than stent recoil is thought to be important for coronary arterial in-stent restenosis. There is only limited data on the cellular and extracellular composition changes with time after stent deployment.

METHODS

We analyzed 29 coronary arterial in-stent restenotic tissue samples (14 left anterior descending coronary artery, 10 right coronary artery, and 5 left circumflex artery) retrieved by using directional coronary atherectomy from 25 patients at 0.5 to 23 (mean, 5.7) months after deployment of Palmaz-Schatz stents employing histochemical and immunocytochemical techniques.

RESULTS

Cell proliferation was low (0% to 4%). Myxoid tissue containing extracellular matrix (ECM) enriched with proteoglycans was found in 69% of cases and decreased over time after stenting. Cell-depleted areas were found in 57% of cases and increased with time after stenting. Versican, biglycan, perlecan, and hyaluronan were present with varying individual distributions in all samples. Positive transforming growth factor-beta1 staining was found in 80% of cases. Immunostaining with alpha-smooth muscle actin identified the majority of cells as smooth muscle cells with occasional macrophages present (< or =12 cells per section).

CONCLUSIONS

These data suggest that enhanced ECM accumulation rather than cell proliferation contribute to later stages of in-stent restenosis. Balloon angioplasty of in-stent restenosis may, therefore, fail due to ECM changes during: 1) additional stent expansion, 2) tissue extrusion out of the stent, or 3) tissue compression.

Repeated intervention for in-stent restenosis of the renal arteries

PURPOSE

To assess the long-term technical success of repeated endovascular intervention in stenosed renal artery stents.

MATERIALS AND METHODS

Fifteen patients with stenoses >or=50% in a renal stent placed because of an ostial atherosclerotic renal artery stenosis were included in this study. In the presence of increased blood pressure or decreased renal function, the in-stent restenosis was treated with percutaneous transluminal angioplasty (PTA) in the stent or placement of a second stent if the stenosis was located too distally in the stent. The results of these repeat interventions were evaluated by angiography.

RESULTS

The 15 patients had a total of 20 stenosed stents. Eighteen of these in-stent stenoses were treated with PTA and two were treated with placement of a second stent. Angiographic follow-up was available in 16 arteries, showing in-stent restenosis in four (25%; mean follow-up, 11 mo). The cumulative patency rates after repeat endoluminal intervention were 93% (95% CI: 80%-106%) and 76% (95% CI: 52%-101%) after 6 and 12 months, respectively. Renal function remained stable or improved in most patients (80%) after repeated intervention in the stent, and hypertension was classified as improved or cured in 47% of patients after 1 year.

CONCLUSION

Patients with stenosed renal artery stents can be treated successfully with PTA in a majority of cases, with a long-term success rate of 75% and stable renal function 1 year after repeated intervention.

Combined cutting balloon angioplasty and intracoronary beta radiation for treatment of in-stent restenosis: clinical outcomes and effect of pullback radiation for long lesions

Intracoronary beta (beta) radiation decreases the incidence of target lesion revascularization after percutaneous intervention (PCI) for in-stent restenosis (ISR). Cutting balloon (CB) angioplasty may also be superior to other percutaneous techniques for the treatment of ISR. We sought to study the outcomes of patients with ISR who underwent both CB angioplasty and intracoronay beta radiation and compare them to patients with ISR who underwent other PCI techniques without concomitant radiation. We also sought to evaluate the safety and efficacy of pullback intracoronary beta radiation for the treatment of long ISR lesions. Between January 2001 and November 2001, 102 patients (mean age = 55 +/- 13 years) with ISR underwent both CB angioplasty and intracoronay beta radiation. beta radiation was delivered using the Beta Cath (Novoste) 30 mm system, and pullback radiation was performed in 41 patients. A comparison group included a total of 393 patients with ISR who underwent other PCI techniques without concomitant intracoronary radiation therapy. Follow-up was obtained in 99 patients (97%) in the CB angioplasty with intracoronary radiation group and 377 patients (96%) in the comparison group. At follow-up, both target vessel revascularization (TVR) and major adverse cardiovascular events (MACE) occurred significantly less in the CB angioplasty with intracoronary radiation group than in the comparison group (7% vs. 18% for TVR, and 14% vs. 24% for MACE; P < 0.05 for both). In the pullback radiation group, TVR was performed in five patients (12%), and MACE occurred in eight patients (20%). A combination of CB angioplasty and intracoronay beta radiation for ISR seems to yield low rates of subsequent target vessel revascularization and adverse cardiac events. In addition, pullback beta radiation using the Beta Cath (Novoste) 30 mm system is safe and can be used to treat long ISR lesions effectively. Further randomized trials are needed to confirm these findings.