Management of restenosis within the Palmaz-Schatz coronary stent (the U.S. multicenter experience. The U.S. Palmaz-Schatz Stent Investigators

On the importance of modeling balloon folding, pleating, and stent crimping: An FE study comparing experimental inflation tests

Finite element (FE)-based studies of preoperative processes such as folding, pleating, and stent crimping with a comparison with experimental inflation tests are not yet available. Therefore, a novel workflow is presented in which residual stresses of balloon folding and pleating, as well as stent crimping, and the geometries of all contact partners were ultimately implemented in an FE code to simulate stent expansion by using an implicit solver. The numerical results demonstrate that the incorporation of residual stresses and strains experienced during the production step significantly increased the accuracy of the subsequent simulations, especially of the stent expansion model. During the preoperative processes, stresses inside the membrane and the stent material also reached a rather high level. Hence, there can be no presumption that balloon catheters or stents are undamaged before the actual surgery. The implementation of the realistic geometry, in particular the balloon tapers, and the blades of the process devices improved the simulation of the expansion mechanisms, such as dogboning, concave bending, or overexpansion of stent cells. This study shows that implicit solvers are able to precisely simulate the mentioned preoperative processes and the stent expansion procedure without a preceding manipulation of the simulation time or physical mass.

Current Role of Laser Angioplasty of Restenotic Coronary Stents

Treatment of in-stent restenosis (ISR) with conventional percutaneous transluminal coronary angioplasty (PTCA) causes significant recurrent neointimal tissue growth in 30-85%. Therefore, laser ablation of intrastent neointimal hyperplasia before balloon dilation can be an attractive alternative. However, the long-term outcomes of such treatment have not been studied thoroughly enough. This prospective case-control study evaluated angiographic and clinical outcomes of PTCA alone and a combination of excimer laser coronary angioplasty (ELCA) and adjunct PTCA in 125 patients with ISR. ELCA was performed before balloon dilation in 67 patients, PTCA alone was performed in 58 patients. Basic demographic and clinical data were comparable in both groups. Lesions included in ELCA group were longer (17.1 ±9.9 vs 13.6 ±9.1 mm; p=0.034), more complex (36.5% type C stenoses vs 14.3%; p=0.006), and more frequently had reduced distal blood flow (TIMI <3: 18.9% vs 4.8%; p=0.025) compared to lesions in the PTCA group. Immediate angiographic results of PTCA and ELCA + PTCA appeared to be comparable. PTCA alone was successful in 57 patients (98.3%), ELCA + PTCA, in 66 patients (98.5%). The rates of hospital complications were comparable (3.0% in ELCA group vs 8.6% in PTCA group). The 1-year follow-up showed that the rates of major adverse cardiac events (MACE) were comparable in the 2 groups (37.3% in ELCA group vs 46.6% in PTCA group). The rates of target vessel revascularization (TVR) within 1 year after the intervention were also similar in the 2 groups (32.8% vs 34.5%). The data mean that ELCA in patients with complex ISR is efficient and safe. Despite a higher complexity of lesions in the ELCA group, no increase in the rate of complications was registered.

Stenting for Extracranial Stenotic Lesions of Carotid and Vertebral Arteries

We evaluated the feasibility of stenting in four patients. Two cases were vertebral osteal stenosis and the others were carotid stenosis at high position with ulcers. We placed balloon expandable coronary stents by a bared stent technique. The mean preprocedural stenosis (86.58%) was reduced to 13.05%. Patients were examined clinically and angiographically at 1, 3 and 6 months after stenting. There was no minor nor major stroke during and after the procedures. Asymptomatic restenosis occurred in the cases of proximal vertebral arteries. One of these patients needed to repeat balloon dilatation. There were no angiographic restenoses in the location of stenting in the carotid artery.

In the treatment for atherosclerotic stenoses, stent placement is a feasible and safe method. However restenosis in a vertebral osteal lesion should be carefully followed after stent placement.

Middle-term results of percutaneous coronary intervention with standard metallic stent “Ephesos II” implantation in patients with coronary heart disease

Aim. In a non-randomised study, to assess middle-term (9 months) effectiveness and safety of percutaneous coronary intervention (PCI) with “Ephesos II” stent implantation. Material and methods. The study included 41 patients, treated at the Sani Konukoglu Medical Centre, Gaziantep, Turkey. Results. Immediate angiography-confirmed PCI success was achieved in 100 % of the participants. Nine months after the intervention, the percentage of survived patients without restenosis and repeat revascularization was 77,6 %. Control angiography at 9 months was performed in 95,1 % of the patients. The mean in-stent late loss was 0,32±0,25. Restenosis was observed in 22,4 % of the subjects. In all cases of in-stent restenosis, successful repeat PCI was performed. At 9 months, the proportion of the survived patients without moderate to severe cardiac complications and events reached 70,3 %. Conclusion. This non-randomised study demonstrated good short and middle-term results of PCI with standard metallic stent “Ephesos II” implantation.

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.

Implications of the "watermelon seeding" phenomenon during coronary interventions for in-stent restenosis

The occurrence of balloon slippage ("watermelon seeding"; WMS) during treatment of patients with in-stent restenosis (ISR) has been described, but predisposing factors and the potential implications of this phenomenon remain unknown. In the Restenosis Intrastent: Balloon Angioplasty vs. Elective Stenting (RIBS) randomized study, 450 patients with ISR were included. Of these, 42 patients (9%) presented WMS during the procedure. WMS was detected in 26 patients (12%) in the balloon arm and 16 (7%) in the stent arm (P=0.11). In the stent arm, WMS was only noticed during balloon predilation, never during stent implantation. As compared with 408 patients without WMS, patients with WMS had more severe (TIMI flow 1; 21% vs. 8%; P=0.01) and diffuse (length>15 mm: 45% vs. 28%; P=0.02) ISR lesions. Patients with WMS required more balloon inflations, longer total inflation time, had more frequent crossover to stenting or ended the procedure with residual dissections, and eventually obtained poorer acute results (minimal lumen diameter, 2.35+/-0.5 vs. 2.53+/-0.5 mm; P=0.03). In addition, at 6-month follow-up, patients with WMS had a smaller minimal lumen diameter (1.26+/-0.7 vs. 1.61+/-0.7 mm; P=0.007) and a higher restenosis rate (56% vs. 37%; P=0.017). On logistic regression analysis, the WMS phenomenon emerged as an independent predictor of recurrent restenosis (adjusted RR=2.1; 95% CI=1.1-4.1; P=0.04). The WMS phenomenon may complicate treatment of patients with ISR. Long and severe lesions appear to predispose to this technical problem that never occurs during stent deployment. In patients with ISR, WMS is associated with cumbersome procedures and poorer acute and long-term angiographic results.

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.

Cutting Balloon: Review on Principles and Background of Use in Peripheral Arteries

This review describes peripheral use of cutting balloon (CB) angioplasty (CBA), its characteristics, and its distinction from conventional BA and describes the experimental and clinical background of its current use in peripheral arteries.

Fractional flow reserve for the prediction of cardiac events after coronary stent implantation: results of a multivariate analysis

OBJECTIVE

To determine the prognostic value of fractional flow reserve (FFR) measurements after coronary stent implantation including multiple clinical and angiographic parameters collected in one centre.

METHODS

119 consecutive patients were enrolled who had a stent implanted with the use of a pressure wire as a guidewire. Patients were followed up for at least six months. Any death, myocardial infarction, and target vessel revascularisation were considered major adverse cardiac events (MACE). Multivariate logistic regression was used to determine adjusted odds ratios (OR) and 95% confidence intervals (CI) for FFR and covariates.

RESULTS

Complete follow up data were available for all 119 patients. Pre-interventional FFR increased from 0.65 (0.15) to 0.94 (0.06) (p < 0.0001) after stent implantation. Eighteen MACE (15%) occurred during follow up including 15 (12.6%) target vessel revascularisations. Final FFR was significantly higher in patients without than in patients with an event (0.95 (0.05) v 0.88 (0.08), p = 0.001). In the multivariate logistic regression analysis, only final FFR < 0.95 (OR 6.22, 95% CI 1.79 to 21.62, p = 0.004) and reduced left ventricular function (OR 0.95, 95% CI 092 to 0.99, p = 0.021) remained as significant independent predictors for MACE.

CONCLUSION

These results including multiple parameters underline that FFR after coronary stenting is a strong and independent predictor for subsequent cardiac events after six months' follow up.

Repeat stenting for the prevention of the early lumen loss phenomenon in patients with in-stent restenosis. Angiographic and intravascular ultrasound findings of a randomized study

BACKGROUND

Early lumen loss (ELL) may be detected in patients undergoing coronary interventions for in-stent restenosis. This phenomenon may contribute to recurrences. This prospective, randomized study was designed to determine if repeat stent implantation may prevent ELL in patients with in-stent restenosis.

METHODS

Forty patients were randomized: 20 were allocated to elective stent implantation and 20 to conventional balloon angioplasty. Quantitative coronary angiography and intravascular ultrasound (IVUS) volumetric studies were systematically performed (1) before the procedure, (2) immediately after intervention, and (3) 30 to 60 minutes later.

RESULTS

Baseline characteristics were similar in both groups. After the delay time interval (46 +/- 8 minutes), quantitative coronary angiography revealed a significant reduction in minimal lumen diameter (2.2 +/- 0.5 mm vs 1.7 +/- 0.5 mm, P < .001) in the balloon angioplasty arm. Likewise, in this group, IVUS demonstrated a reduction in mean lumen area (7.1 +/- 2 mm2 vs 6.2 +/- 2 mm2 , P < .001) and lumen volume (144 +/- 59 mm3 vs 126 +/- 54 mm3 , P < .001). In 4 of these patients, ELL was severe enough to require further intervention. In the stent arm, however, angiographic data and IVUS mean lumen area (7.7 +/- 3 mm2 vs 7.7 +/- 3 mm2) and lumen volume (161 +/- 72 mm3 vs 160 +/- 69 mm3) remained unchanged after the delay time interval. On multivariate analysis, stent implantation was an independent predictor of the absence of ELL by quantitative coronary angiography and by IVUS. In addition, patients with a larger ELL on IVUS had a lower event-free survival at 1 year (40% vs 79%, log rank P = .003).

CONCLUSIONS

This randomized study demonstrates that (1) ELL is frequently detected after treatment of in-stent restenosis with balloon angioplasty, that (2) ELL influences the long-term clinical outcome of these patients, and that (3) repeat stent implantation prevents ELL.

[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.

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.

Catheter based intracoronary brachytherapy leads to increased platelet activation

BACKGROUND

Vascular brachytherapy (VBT) after percutaneous coronary intervention (PCI) is associated with a higher risk of stent thrombosis than conventional treatment.

OBJECTIVE

To investigate in vivo periprocedural platelet activation with and without VBT, and to assess a possible direct effect of radiation on platelet activation.

DESIGN

Of 50 patients with stable angina, 23 received VBT after PCI, while 27 had PCI only. The 23 patients who received VBT after PCI were pretreated for one month with aspirin and clopidogrel. Platelet activation was assessed by flow cytometry.

RESULTS

The two patient groups did not differ in their platelet activation before the intervention. There was a significant increase in activation immediately after VBT, with 21.2% (interquartile range 13.0% to 37.6%) thrombospondin positive and 54.0% (42.3% to 63.6%) CD 63 positive platelets compared with 12.7% (9.8% to 14.9%) thrombospondin positive and 37.9% (33.2% to 45.2%) CD 63 positive platelets before the intervention (p < 0.001 and p < 0.01, respectively). Patients without VBT had no periprocedural difference in platelet activation immediately after PCI. No increase in platelet activation was found after ex vivo irradiation of blood samples obtained from healthy controls.

CONCLUSIONS

Catheter based intracoronary VBT carried out according to current standards is highly thrombogenic. The current antithrombotic treatment with aspirin and clopidogrel is not sufficient to suppress platelet activation during the procedure. From in vitro experiments, it appears that platelet activation during brachytherapy is not caused by irradiation but by the procedure of catheter based VBT.

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.

Five-Year Follow-Up After Intracoronary Gamma Radiation Therapy for In-Stent Restenosis

Background— The Washington Radiation for In-Stent Restenosis Trial is a double-blinded randomized study evaluating the effects of intracoronary radiation therapy (IRT) in patients with in-stent restenosis (ISR).

Methods and Results— One hundred thirty patients with ISR (100 native coronary and 30 vein grafts) underwent percutaneous transluminal coronary angioplasty, laser ablation, rotational atherectomy, or additional stenting (36% of lesions). Patients were randomized to either 192-Iridium IRT or placebo, with a prescribed dose of 15 Gy to a 2-mm radial distance from the center of the source. Angiographic restenosis (27% versus 56%, P =0.002) and target vessel revascularization (26% versus 68%, P <0.001) were reduced at 6 months in patients treated with IRT. Between 6 and 60 months, patients treated with IRT compared with placebo had more target lesion revascularization (IRT, 21.6% versus placebo, 4.7%; P =0.04) and target vessel revascularization (IRT, 21.5% versus placebo, 6.1%; P =0.03). At 5 years, the major adverse cardiac event rate was significantly reduced with IRT (46.2% versus 69.2%, P =0.008).

Conclusions— In the Washington Radiation for In-Stent Restenosis Trial, patients with ISR treated with IRT using 192-Iridium had a reduction in the need for repeat target lesion and vessel revascularization at 6 months and 5 years.

Intracoronary beta brachytherapy as a treatment option for high-risk refractory in-stent restenosis

BACKGROUND

Vascular (VBT) has clearly been shown in multiple clinical trials to decrease restenosis rates for in-stent restenosis (ISR). However, patients enrolled in these randomized clinical trials represent a select group, and the efficacy of VBT in patients with ISR who were excluded from these controlled trials due to more complex coronary anatomy requires further investigation. This study sought to define the angiographic and clinical profile and outcomes of these high-risk patients with ISR who were excluded from the randomized clinical trials and who received VBTusing Strontium-90 (Sr-90) using the Novoste Beta-Cath System through a Compassionate Use Protocol (CUP).

METHODS

The study was designed as a single center, prospective, open label registry trial evaluating the use of VBT on complex instent restenotic lesions in patients who were excluded from the START and START 40 trials. In general, these patients included those with saphenous vein graft (SVG) lesions, long lesions (>35 mm), and patients with a history of more than three prior interventions. VBT using Sr-90 was delivered using the Novoste Beta-Cath System after successful angioplasty. The predetermined primary endpoint was freedom from target vessel revascularization (TVR) at 8 months, one and two years. The secondary endpoint was a composite of death, myocardial infarction (MI) and TVR at 8 months, one year, and two years.

RESULTS

Between September 4, 1998 and December 6, 2000, 32 patients were treated with VBT under the UCP protocol. The mean duration of follow up was 15.3 +/- 8.3 months. There were 9 major cardiac events at eight months including one death, one acute myocardial infarction and 7 TVR. Excluding the one patient who died, 33 lesions were available for follow-up. The rate of TVR in this high-risk patient population was 21.1% (n = 7/33 lesions). The method of revascularization included one bypass surgery and 6 repeat percutaneous coronary interventions.

CONCLUSIONS

This trial demonstrates that utilization of the Beta-Cath System using Sr-90 for the treatment of ISR in a patient population excluded from the randomized clinical trials due to unfavorable lesions characteristics is feasible appears to be associated TVR rates that compare favorably with the event rates of patients enrolled in other trials enrolling lower-risk groups.

Contribution of early lumen loss after balloon angioplasty for in-stent restenosis to lumen loss at follow-up

The treatment of in-stent restenosis using balloon angioplasty alone often produces excellent early results, but is associated with high rate of recurrence. Previous studies have demonstrated significant tissue reintrusion shortly after the treatment of in-stent restenosis with balloon angioplasty. The study was designed to elucidate the contribution of early lumen loss 6 hr after balloon angioplasty to lumen loss at follow-up. We prospectively performed quantitative coronary angiography and intravascular ultrasound in 12 patients with in-stent restenosis before intervention, after the final procedure, 6 hr later (5.6 +/- 1.4 hr), and at follow-up (7.7 +/- 2.3 months). Compared with immediately after balloon angioplasty, by 6 hr postintervention, the minimum lumen diameter (MLD) and lumen cross-sectional area had decreased significantly (2.48 +/- 0.44 to 2.01 +/- 0.57 mm, P = 0.01, and 7.0 +/- 1.2 to 5.5 +/- 1.4 mm2, P = 0.004, respectively). Furthermore, the MLD decreased further between 6 hr postintervention and long-term follow-up (2.01 +/- 0.57 to 1.55 +/- 0.64 mm; P = 0.001). Patients who showed recurrence of restenosis at follow-up had greater early lumen loss than patients without recurrence of restenosis (0.71 +/- 0.31 vs. 0.23 +/- 0.13 mm; P = 0.006). Diffuse lesions had greater early lumen loss compared to focal lesions (0.75 +/- 0.35 vs. 0.28 +/- 0.13 mm; P = 0.008). Early lumen loss is common after the treatment of in-stent restenosis by balloon angioplasty. Within the first 6 hr postintervention, 32% +/- 29% of acute lumen gain is lost, and early lumen loss contributed to 42% +/- 18% of total lumen loss at follow-up.

Sirolimus-eluting stents versus standard stents in patients with stenosis in a native coronary artery

BACKGROUND

Preliminary reports of studies involving simple coronary lesions indicate that a sirolimus-eluting stent significantly reduces the risk of restenosis after percutaneous coronary revascularization.

METHODS

We conducted a randomized, double-blind trial comparing a sirolimus-eluting stent with a standard stent in 1058 patients at 53 centers in the United States who had a newly diagnosed lesion in a native coronary artery. The coronary disease in these patients was complex because of the frequent presence of diabetes (in 26 percent of patients), the high percentage of patients with longer lesions (mean, 14.4 mm), and small vessels (mean, 2.80 mm). The primary end point was failure of the target vessel (a composite of death from cardiac causes, myocardial infarction, and repeated percutaneous or surgical revascularization of the target vessel) within 270 days.

RESULTS

The rate of failure of the target vessel was reduced from 21.0 percent with a standard stent to 8.6 percent with a sirolimus-eluting stent (P<0.001)--a reduction that was driven largely by a decrease in the frequency of the need for revascularization of the target lesion (16.6 percent in the standard-stent group vs. 4.1 percent in the sirolimus-stent group, P<0.001). The frequency of neointimal hyperplasia within the stent was also decreased in the group that received sirolimus-eluting stents, as assessed by both angiography and intravascular ultrasonography. Subgroup analyses revealed a reduction in the rates of angiographic restenosis and target-lesion revascularization in all subgroups examined.

CONCLUSIONS

In this randomized clinical trial involving patients with complex coronary lesions, the use of a sirolimus-eluting stent had a consistent treatment effect, reducing the rates of restenosis and associated clinical events in all subgroups analyzed.

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.

Side branch protection with hydrophilic polymer coated guide wire during cutting balloon angioplasty of a bifurcated lesion

Cutting balloon angioplasty (CBA) was performed in a patient with in-stent restenosis (ISR) which had an important side branch. We used a hydrophilic polymer-coated guide wire for side branch protection during CBA. After CBA was successfully performed, the cutting balloon and guide wire were microscopically examined and proven to have suffered minor damage which, in itself, did not disturb the procedure. Hydrophilic polymer-coated wire might be an effective and safe choice for ISR which needs to be treated by CBA while protecting an important side branch.

Correlates of failure following treatment with Sr-90 beta irradiation for in-stent restenosis

We sought to determine the correlates of failure following intracoronary radiation therapy (IRT) with Sr-90 using the Novoste Beta-Cath system for the treatment of in-stent restenosis (ISR) in a broad range of patients. IRT has been shown to be more efficacious compared to placebo for the treatment of ISR in large randomized trials. However, even in patients treated with IRT, major adverse cardiac events occur in approximately 20% of cases on follow-up. This trial sought to elucidate the correlates of failure following successful IRT for ISR. To determine the correlates of IRT failure, we retrospectively compared the demographics, lesion characteristics, and clinical outcomes of 102 consecutive patients with ISR treated with Sr-90 from September 1998 to July 2001. IRT failure was defined as death, myocardial infarction (MI), or target vessel revascularization (TVR) due to repeat ISR on follow-up. A comparison of the clinical and angiographic profile of IRT failures (n = 16) vs. IRT successes (n = 86) revealed that a history of smoking (75% vs. 40%; P = 0.012), current use of calcium channel blockers (84% vs. 45%; P = 0.013), ostial location of target lesion (44% vs. 16%; P = 0.020), and mean posttreatment minimal luminal diameter (MLD; 1.64 +/- 0.19 vs. 2.21 +/- 0.29 mm; P < 0.001), respectively, were correlated with failure using univariate analysis. After multivariate regression analysis, the correlates of failure that remained significant were treatment of an ostial lesion (OR = 31.2; 95% CI = 2.6-382.7; P = 0.007) and final posttreatment MLD (P < 0.001). Ostial location of target lesion and smaller posttreatment MLD are correlated with subsequent death, MI, and TVR following therapy with Sr-90 for ISR.

Risk assessment by myocardial perfusion imaging for coronary revascularization, medical therapy, and noncardiac surgery

Stress myocardial perfusion imaging (MPI) has become an important tool in risk stratification of patients with known coronary artery disease. A normal myocardial perfusion scan has a high negative predictive value and is associated with low annual mortality rate (< 1%). Patients with extensive ischemia (> 20% of the left ventricle), defects in more than 1 coronary vascular territory, transient or persistent left ventricular cavity dilation, and ejection fraction less than 45% have a high annual mortality rate (> 3%). Those patients should undergo coronary revascularization whenever feasible, as the cardiac event rate increases in proportion to the magnitude of the jeopardized myocardium. Stress MPI can be used to demonstrate ischemia in patients with symptoms early after coronary artery bypass surgery (< 5 years) or in those without symptoms late (>/= 5 years) after coronary artery bypass surgery. With respect to patients who underwent percutaneous interventions, stress MPI can help detect in-stent restenosis early after the intervention (3-6 months) or assess the progression of native coronary disease afterward. Since preliminary data suggest that a reduction in the perfusion defect size may translate to a reduction of coronary events, stress MPI can help assess the efficacy of medical management of coronary disease. Finally, stress MPI is indicated for perioperative cardiac risk stratification for noncardiac surgery in patients with intermediate risk predictors (mild angina, prior myocardial infarction or heart failure symptoms, diabetes mellitus, renal insufficiency) and poor functional capacity or in those who undergo high-risk surgery with significant implications in further preoperative management.

Directional coronary atherectomy vs. rotational atherectomy for the treatment of in-stent restenosis of native coronary arteries

Management of in-stent restenosis has become a significant challenge in interventional cardiology. Since the mechanism of in-stent restenosis is predominantly intimal hyperplasia, debulking techniques have been used to treat this condition. This study is a nonrandomized comparison of the immediate and long-term results of directional coronary atherectomy (DCA; n = 58) vs. high-speed rotational atherectomy (ROTA; n = 61) for the treatment of in-stent restenosis of native coronary arteries. There were no in-hospital deaths, Q-wave myocardial infarctions, or emergency coronary artery bypass surgery in either group. DCA resulted in a larger postprocedural minimal luminal diameter of (2.57 +/- 0.51 vs. 2.14 +/- 0.37 mm; P < 0.0001) and a larger acute gain (1.83 +/- 0.52 vs. 1.42 +/- 0.48 mm; P < 0.0001). Furthermore, 12-month clinically indicated target lesion revascularization (39% vs. 21%; P = 0.02) and long-term follow-up MACE (44% vs. 28%; P = 0.03) was greater in the ROTA group. The present study suggests that DCA appears to be superior to ROTA for the treatment of in-stent restenosis of native coronary arteries. Compared to ROTA, the debulking effect of DCA leads to a larger postprocedure minimal luminal diameter, and a lower incidence of subsequent target lesion revascularization and MACE.

Predictors of late cardiac events following treatment with Sr-90 beta-irradiation for instent restenosis

BACKGROUND

Intracoronary radiation therapy (IRT) with Sr-90 using the Novoste Beta-Cath system has been shown to be an effective therapy for instent restenosis (ISR), but the temporal occurrence of cardiac events and the predictors of late complications require further investigation.

METHODS

We analyzed the demographics, lesion characteristics and clinical outcomes of 138 consecutive patients with ISR treated with IRT from September 1998 to March 2002. Major adverse cardiac events (MACE) were defined as death, myocardial infarction (MI) or target vessel revascularization (TVR). Characteristics of early (< or =8 months) and late (>8 months) failures were analyzed.

RESULTS

Thirty-two (23.1%) of 138 patients had MACE on follow-up; 25% (8/32) of failures occurred late after treatment with IRT. A comparison of the clinical and angiographic profile of early and late failures using univariate analysis indicates no correlations to late failure following IRT. Duration to failure after IRT was 14.25+/-3.69 months in the late group compared to 4.63+/-2.86 months in the early group (P<.001).

CONCLUSIONS

Late MACE after IRT with Sr-90 for ISR occur beyond the traditional period for clinical restenosis in 25% of cases and are difficult to predict. Further study is warranted to identify patients at risk for the development of late complications after IRT.

Efficacy and feasibility of helixcision for debulking neointimal hyperplasia for in-stent restenosis

The Helixcision system is a novel 6 Fr-compatible catheter designed to debulk tissue for in-stent restenosis lesions. The purpose of this study was to determine the efficacy and feasibility of this new system for removing neointimal hyperplasia. A total of 32 in-stent restenosis lesions in 32 patients were treated with helixcision followed by balloon angioplasty. Debulking efficacy was assessed with serial baseline intravascular ultrasound (IVUS) in a subset of 18 lesions. To investigate longitudinal efficacy, 3D analysis was also performed in 12 lesions with automated pullback to calculate average cross-sectional areas across the stent. Prior to procedure, the angiographic reference diameter was 2.60 +/- 0.46 mm. Immediately after procedure, minimum lumen diameter improved from 0.84 +/- 0.33 to 2.19 +/- 0.41 mm (P < 0.0001). IVUS showed a significant reduction of intimal area (IA) after helixcision (from 4.95 +/- 2.04 to 2.88 +/- 1.48 mm(2); P < 0.001). Adjunctive balloon angioplasty further improved lumen area (LA) mainly by stent expansion rather than IA reduction at the site of minimum lumen area. The degrees of IA reduction and LA improvement were closely similar in volumetric analysis. Thirty-day and 6-month clinical follow-up were available in 97% (n = 31) and 72% (n = 23) of the enrolled patients, respectively. At 30-day follow-up, no major adverse cardiac event was reported except for periprocedural CK elevation in two patients (6%). Target legion revascularization within 6 months was performed in six patients (26%). Preliminary results of helixcision indicate that this system is safe and feasible for the treatment of in-stent restenosis. The concordant results between 2D and 3D IVUS analyses suggest that this unique technology can achieve uniform longitudinal debulking throughout the stent. The long-term outcomes appeared to be favorable, considering the relatively diffuse lesion morphology.

Geographical miss during intracoronary irradiation: impact on restenosis and determination of required safety margin length

OBJECTIVE

The goal of this study was to evaluate the incidence and effects of underdosage of injured segments during intracoronary irradiation and to define the minimal length of safety margin required to avoid mismatched source placement.

BACKGROUND

Underdosage of injured segments due to misplacement of active source has been suggested as the underlying mechanism for the occurrence of edge restenosis.

METHODS

Baseline angiograms of 112 vessels in 109 patients with in-stent restenosis undergoing coronary reintervention followed by intracoronary irradiation ((192)Ir: Checkmate, Cordis, Miami, Florida; (32)P: Gallileo, Guidant, Houston, Texas; (90)Sr/Y: Beta-Cath, Novoste, Norcross, Georgia) were analyzed. The distances between the outermost injury and outermost end of "reference isodose length" (RIL), defined as a segment with >/=90% of reference dose at 1 mm vessel wall depth, were measured. "Safety margin" was defined as the distance between the outermost injury and outermost end of the RIL, "geographical miss" (GM) as a complete injured segment not being covered by the RIL, and "restenosis" as the percent diameter stenosis >50%.

RESULTS

Baseline angiographic analysis was performed for 224 edges in 112 vessels. Geographical miss was found in 46 (20.6%) edges. The incidence of target lesion restenosis within the 78 vessels with available follow-up was 43.3% for patients with GM versus 14.9% for patients with no GM (p = 0.005). Analysis of various injured segments exposed highest restenosis rates in injured segments with negligible irradiation (27.8%) in comparison with injured segments with dose fall-off (16.7%) or injured segments with full-dose irradiation (7.7%) (p = 0.006). Receiver operating curve analysis revealed a safety margin of 10 mm required per vessel (i.e., 5-mm safety margin/edge) to achieve 95% specificity of GM.

CONCLUSIONS

Geographical miss is associated with a higher incidence of restenosis at the corresponding edges. Restenosis was more pronounced in injured segments with negligible irradiation than in injured segments at the dose fall-off zones. We recommend a safety margin of 10 mm per vessel to minimize GM.

Randomized trial of 90Sr/90Y beta-radiation versus placebo control for treatment of in-stent restenosis

BACKGROUND

After conventional treatment of in-stent restenosis, the incidence of recurrent clinical restenosis may approach 40%. We report the first multicenter, blinded, and randomized trial of intracoronary radiation with the use of a 90Sr/90Y beta-source for the treatment of in-stent restenosis.

METHODS AND RESULTS

After successful catheter-based treatment of in-stent restenosis, 476 patients were randomly assigned to receive an intracoronary catheter containing either 90Sr/90Y (n=244) or placebo (n=232) sources. The prescribed dose 2 mm from the center of the source was 18.4 Gy for vessels between 2.70 and 3.35 mm in diameter and 23.0 Gy for vessels between 3.36 and 4.0 mm. The primary end point, ie, clinically driven target-vessel revascularization by 8 months, was observed in 56 (26.8%) of the patients assigned to placebo and 39 (17.0%) of the patients assigned to radiation (P=0.015). The incidence of the composite including death, myocardial infarction, and target-vessel revascularization was observed in 60 (28.7%) of the patients assigned to placebo and 44 (19.1%) of the patients assigned to radiation (P=0.024). Binary 8-month angiographic restenosis (> or =50% diameter stenosis) within the entire segment treated with radiation was reduced from 45.2% in the placebo-treated patients to 28.8% in the 90Sr/90Y-treated patients (P=0.001). Stent thromboses occurred in 1 patient assigned to placebo <24 hours after the procedure and in 1 patient assigned to 90Sr/90Y at day 244.

CONCLUSIONS

The results of this study demonstrated that beta-radiation using 90Sr/90Y is both safe and effective for preventing recurrence in patients with in-stent restenosis.

Coronary artery brachytherapy

Coronary artery disease is the leading cause of mortality in the West with over 1.2 million angioplasties performed annually. Despite the introduction of stents, restenosis occurs in 30-40% of vessels, which until recently has only been treated effectively by coronary artery bypass surgery. Coronary artery brachytherapy appears to provide an alternative, less invasive remedy. The mechanisms of restenosis and how these are inhibited by radiation are described here. The practicalities of radiation delivery and the history of the development of intravascular radiation as an effective clinical tool are outlined. Finally, the pitfalls of the current technology and the areas in which future research must be targeted for the field to develop are discussed.

Resource utilization, cost, and health status impacts of coronary stent versus "optimal" percutaneous coronary angioplasty: results from the OPUS-I trial

In the OPUS-I trial, primary coronary stent implantation reduced 6-month composite incidence of death, myocardial infarction, cardiac surgery, or target vessel revascularization relative to a strategy of initial PTCA with provisional stenting in patients undergoing single vessel coronary angioplasty. The purpose of this research was to compare the economic and health status impacts of each treatment strategy. Resource utilization data were collected for the 479 patients randomized in OPUS-I. Itemized cost estimates were derived from primary hospital charge data gathered in previous multicenter trials evaluating coronary stents, and adjusted to approximate 1997 Medicare-based costs for a cardiac population. Health status at 6 months was assessed using the Seattle Angina Questionnaire (SAQ). Initial procedure related costs for patients treated with a primary stent strategy were higher than those treated with optimal PTCA/provisional stent ($5,389 vs $4,339, P < 0.001). Costs of initial hospitalization were also higher for patients in the primary stent group ($9,234 vs $8,434, P < 0.01) chiefly because of the cost differences in the index revascularization. Mean 6-month costs were similar in the two groups; however, there was a slight cost advantage associated with primary stenting. Bootstrap replication of 6-month cost data sustained the economic attractiveness of the primary stent strategy. There were no differences in SAQ scores between treatment groups. In patients undergoing single vessel coronary angioplasty, routine stent implantation improves important clinical outcomes at comparable, or even reduced cost, compared to a strategy of initial balloon angioplasty with provisional stenting.

Abciximab administration and clinical outcomes after percutaneous intervention for in-stent restenosis

Abciximab therapy improves clinical outcomes after percutaneous interventions for de novo coronary artery disease. We sought to determine whether clinical outcomes after percutaneous intervention for in-stent restenosis are affected by abciximab administration. Between January 1996 and July 1999, 322 consecutive patients underwent percutaneous intervention for in-stent restenosis; 157 patients received abciximab and 165 patients were treated without abciximab based on operator discretion. Baseline clinical and angiographic variables and type of percutaneous intervention were recorded. Follow-up information was obtained and clinical endpoints were recorded. A multivariate analysis was performed to determine the independent variables associated with adverse clinical outcomes. Baseline clinical and angiographic variables were similar in both groups. Patients who received abciximab were more likely to be treated with rotational atherectomy and less likely to have only balloon angioplasty or repeat stenting. Mean follow-up duration was 19 +/- 12 months. There were no significant differences in the incidence of angina/myocardial infarction (29% vs. 30%; P = 0.9), target vessel revascularization (18% vs. 21%; P = 0.5), death (8% vs. 7%; P = 0.4), or major adverse cardiovascular events (38% vs. 39%; P = 0.9) in both groups. Abciximab administration was not an independent variable associated with adverse outcomes. In this observational study, clinical outcomes after percutaneous intervention for in-stent restenosis did not seem to be affected by abciximab administration. Randomized trials are needed to identify the role of platelet glycoprotein IIb/IIIa inhibitors in the management of in-stent restenosis.

Mechanism of cutting balloon angioplasty for in-stent restenosis: an intravascular ultrasound study

We investigated by intravascular ultrasound (IVUS) the mechanism of action of cutting balloon (CB) angioplasty in patients with in-stent restenosis. Seventy-one consecutive restenotic lesions of 66 patients were studied by quantitative coronary angiography (QCA) and IVUS before, immediately after, and, in 20 cases, at 24-hr time interval after CB. CB was selected according to 1:1 CB-to-stent ratio and inflated at 8 atm for 60-90 sec. Both IVUS planar and volumetric (Simpson's rule, 25 patients) analysis were carried out. IVUS measurements included external elastic membrane area (EEMA), stent area (SA), minimal lumen area (MLA), and restenosis area (RA). Following CB, QCA analysis showed increase of minimal lumen diameter (1.17 +/- 0.46 vs. 2.45 +/- 0.51 mm; P < 0.0001) and decrease of diameter stenosis (64% +/- 13% vs. 21% +/- 9%; P < 0.0001). IVUS measurements showed a significant increase of MLA (2.18 +/- 0.80 vs. 7.31 +/- 1.8 mm(2); P < 0.0001), SA (9.62 +/- 2.6 vs. 10.7 +/- 2.75 mm(2); P < 0.0001), and EEMA (17.27 +/- 5 vs. 18.1 +/- 5 mm(2); P < 0.0001) and a decrease of RA (7.43 +/- 2.63 vs. 3.45 +/- 1.39 mm(2); P < 0.0001). No significant change was observed in the original plaque + media area (7.65 +/- 3 vs. 7.38 +/- 2.9 mm(2); P = NS). Thus, of the total lumen enlargement (5.13 +/- 1.85 mm(2)), 23% was the result of increase in mean SA, whereas 77% was the result of a decrease in mean RA. These changes were associated with a 5% increase in EEMA. IVUS volumetric changes paralleled planar variations. Angiographic and IVUS changes were well maintained at 24 hr. CB enlarges coronary lumen mainly by in-stent tissue reduction associated with a moderate degree of additional stent expansion. Favorable QCA and IVUS acute results are maintained at 24 hr.

Haptoglobin phenotype and the risk of restenosis after coronary artery stent implantation

We recently demonstrated that an allelic polymorphism in the haptoglobin gene is a major determinant of susceptibility to a number of vascular disorders. We set out to determine if haptoglobin phenotype was predictive of the development of restenosis in a consecutive series of patients, all of whom underwent stent implantation followed by repeat angiography with quantitative coronary angiography analysis 6 months later. This study included 214 consecutive patients undergoing stent implantation for de novo lesions between 1998 and 1999 in Aalst, Belgium. All underwent follow-up quantitative coronary angiography analysis 6 months after the procedure. The haptoglobin phenotype was determined by electrophoresis. No significant differences were found between patients segregated by phenotype with respect to clinical, procedural, and angiographic factors previously suggested to influence the development of restenosis. None of the diabetic patients homozygous for the haptoglobin 1 allele developed restenosis compared with a >50% restenosis rate for diabetic patients with at least 1 haptoglobin 2 allele (p <0.02). In all patients (diabetic and nondiabetic), we observed a trend toward a lower incidence of restenosis in patients homozygous for the 1 allele (21% vs 33%, p <0.09). Moreover, we found a graded risk relation to the number of haptoglobin 2 alleles. The risk of developing restenosis was greater in subjects with 2 haptoglobin 2 alleles (36%) than in those with 1 haptoglobin 2 allele (31%) or no haptoglobin 2 alleles (21%). Thus, knowledge of the haptoglobin phenotype may be useful in assessing and utilizing new therapies that attempt to reduce restenosis, and may have important implications for the risk stratification algorithm used in managing diabetic patients with coronary artery disease.

Use of localised intracoronary beta radiation in treatment of in-stent restenosis: the INHIBIT randomised controlled trial

BACKGROUND

In-stent restenosis is a major limitation of intracoronary stenting. Ionising gamma radiation has been shown to reduce recurrence of restenosis after stent placement. We aimed to compare the effects of intracoronary beta radiation treatment with those of placebo for clinical and angiographic outcomes of patients with diffuse in-stent restenosis.

METHODS

332 patients with in-stent restenosis underwent successful coronary intervention, and were then randomly allocated to intracoronary beta radiation with a phosphorus-32 source (n=166) or placebo (166) delivered into a centreing balloon catheter through an automatic afterloader. Longer lesions (>22 mm of dilated length) were treated with tandem positioning of the study wire. The primary safety endpoint was major adverse cardiac events, defined as death, myocardial infarction, and repeat target-lesion revascularisation at 9 months. The primary efficacy endpoint was binary angiographic restenosis rate in the analysis segment during 9-months' follow-up. Analysis was by intention to treat.

FINDINGS

Procedural success, and in-hospital and 30-day complications were similar among the two groups. 24 (15%) patients in the radiated group had the primary safety endpoint of death, myocardial infarction, or repeat target-lesion revascularisation over 290 days compared with 51 [corrected] (31%) in the placebo group (difference 16% [95% CI 7-25], p = 0.0006). Binary angiographic restenosis rate was lower in the radiated group than the placebo group for the entire analysed segment (difference 25% [14--37], p < 0.0001).

INTERPRETATION

Vascular brachytherapy using pure beta-emitter 32P delivered into a centreing catheter via an automatic afterloader can be used to reduce overall revascularisation in patients undergoing treatment for diffuse in-stent restenosis.

Rotational atherectomy does not reduce recurrent in-stent restenosis: results of the angioplasty versus rotational atherectomy for treatment of diffuse in-stent restenosis trial (ARTIST)

BACKGROUND

Aim of this trial was to compare rotational atherectomy followed by balloon angioplasty (rotablation [ROTA] group) with balloon angioplasty (percutaneous transluminal coronary angioplasty [PTCA] group) alone in patients with diffuse in-stent restenosis.

METHODS AND RESULTS

The ARTIST study is a multicenter, randomized, prospective European trial with 298 patients with in-stent restenosis>70% (mean lesion length, 14 +/- 8 mm) in stents, implanted in coronary arteries for >/= 3 months. In the PTCA group, angioplasty was performed at the discretion of the local investigator, and rotablation was performed by using a stepped-burr approach followed by adjunctive PTCA with low (</= 6 atm) inflation pressure. Intravascular ultrasound during the intervention and at follow-up was used in a substudy in 86 patients (45 PTCA, 41 ROTA). Angiography demonstrated no difference regarding the short-term outcome, with equivalent procedural success rates defined as remaining stenosis <30% (89% PTCA, 88% ROTA). However, the results showed that, in the long term, PTCA was a significantly better strategy than ROTA. Mean net gain in minimal lumen diameter was 0.67 mm and 0.45 mm for PTCA and ROTA, respectively (P=0.0019). Mean gain in diameter stenosis was 25% and 17% (P=0.002), resulting in restenosis (>/= 50%) rates of 51% (PTCA) and 65% (ROTA) (P=0.039). By intravascular ultrasound, the major difference was the missing stent over-expansion during PTCA after ROTA. Six-month event-free survival was significantly higher after PTCA (91.3%) compared with ROTA (79.6%, P=0.0052).

CONCLUSIONS

In terms of the primary objective of the study, PTCA produced a significantly better long-term outcome than ROTA followed by adjunctive low-pressure PTCA.

Treating atherosclerosis: local drug delivery from laboratory studies to clinical trials

Treating only the specific section of the vascular bed that is diseased appears to make sense. Giving drugs systematically to treat perhaps only a few centimetres of affected artery carries with it the risk of systemic side effects and reduced efficacy consequent on low concentrations of agent at the site of the problem. There has thus been great interest since the early 1990s in local drug delivery. Initial targets were the thrombotic response to plaque disruption but the problems arising from the incidental damage inflicted by devices used in interventional cardiology and the pathological consequences of this, namely smooth muscle cell initiated intimal hyperplasia, soon became the focus of pre-clinical studies. Problems to be overcome were the low efficiency of delivery of drugs and the low retention rates. Solutions to these problems included the development of strategies to target drugs, through the use of antibodies directed at antigens newly released at the site of damage. As it became clear that stents were becoming central to the attainment of a better clinical response to intervention by their inherent physical properties, it also became obvious that stents could be used to deliver agents. Issues such as which stent, how to load the drug onto the stent and what drug to use to inhibit the unwanted pathobiological response are ongoing issues.

Intracoronary beta radiation: state of the art

This state-of-the-art review is intended to explore the development of beta radiation including catheter delivered and permanent implants from its inception to current practice. Specific focus will be given to the isotopes currently available, radiation physics of beta emitters, preclinical studies, clinical trials, beta radiation delivery systems, and implications for future practice. The encouraging results from the clinical trials have established vascular brachytherapy as a standard of care for patients with in-stent restenosis. Vascular brachytherapy requires additional "fine-tuning" to achieve full optimization.

Diffuse in-stent restenosis

Stent restenosis, especially the diffuse pattern, has developed into a significant clinical and economical problem. It has been estimated that up to 250,000 patients developed in-stent restenosis in 2,000 alone, two thirds of them can be expected to have diffuse in-stent restenosis, which is difficult to treat because of high recurrence rates. None of the conventionally available interventional treatment modalities provides optimal long-term results. Intravascular radiation therapy is currently the only effective percutaneous therapy for combating in-stent restenosis. Late thrombotic complications have largely been eliminated by extended antiplatelet regimens. Geographical miss, a major reason for recurrence of in-stent restenosis after brachytherapy, can be reduced by an improved radiation technique. The first preliminary data on drug-eluting stents, showing only minimal neointimal proliferation at 6-month postimplantation, could represent a major breakthrough in the quest to solve restenosis.

Effects of 32P radioactive stents on in-stent restenosis in a double stent injury model of the porcine coronary arteries

BACKGROUND

The major limitation of coronary stenting remains in-stent restenosis, due to the development of neointimal proliferation. Radioactive stents have demonstrated the ability to reduce this proliferation in the healthy nonatherosclerotic porcine animal model. However, inhibition of tissue proliferation in the in-stent restenotic lesion in a porcine model is not well characterized. The objective of this study was to examine the efficacy and safety of the 32P radioactive stent for the treatment of in-stent restenosis in a double stent injury model of the porcine coronaries.

METHODS AND MATERIALS

Eighteen coronary arteries in 9 pigs underwent nonradioactive stent (8 mm in length) implantation. Thirty days after the initial stent implantation, a 32P radioactive stent (18 mm in length) with an activity of 0 and 18 microCi was implanted to cover the initial stent. The swine were killed 30 days after the second stent implantation. Histomorphometric analysis was performed for vessel area (VA), stent strut area (SSA), intimal area (IA), and lumen area (LA).

RESULTS

Injury scores, VA, SSA, and LA were similar among the control and radiated groups. Neointimal formation was significantly reduced after placement of radioactive stents as compared to control in both the overlapped (0.93 +/- 0.12 vs. 1.31 +/- 0.51 mm(2), p < 0.05) and nonoverlapped segments (1.14 +/- 0.21 vs. 1.91 +/- 1.04 mm(2), p < 0.05). The smooth muscle cell index in the neointima was reduced. Intimal fibrin was increased in the radiated group as compared to the control (p < 0.01 respectively).

CONCLUSIONS

32P radioactive stents may be safe and effective in reducing neointimal formation leading to in-stent restenosis. Longer follow-up will be required to examine whether these positive findings can be maintained.

Three-year follow-up after intracoronary gamma radiation therapy for in-stent restenosis. Original WRIST. Washington Radiation for In-Stent Restenosis Trial

BACKGROUND

The Washington Radiation for In-Stent Restenosis Trial (WRIST) is a double-blinded randomized study evaluating the effects of intracoronary radiation therapy (IRT) in patients with in-stent restenosis (ISR).

METHODS

One hundred and thirty patients with ISR (100 native coronary and 30 vein grafts) underwent PTCA, laser ablation, rotational atherectomy, and/or additional stenting (36% of lesions). Patients were randomized to either Iridium-192 IRT or placebo, with a prescribed dose of 15 Gy to a 2-mm radial distance from the center of the source.

RESULTS

Angiographic restenosis (27% vs. 56%, P=.002) and target vessel revascularization (TVR; 26% vs. 66%, P<.001) were dramatically reduced at 6 months in IRT patients. Between 6 and 36 months, IRT compared to placebo patients had more target lesion revascularization (TLR; IRT=17% vs. placebo=2%, P=.002) and TVR (IRT=17% vs. placebo=3%, P=.009). At 3 years, the major adverse cardiac event (MACE) rate was significantly reduced with IRT (39% vs. 65%, P=.003).

CONCLUSIONS

In WRIST, patients with ISR treated with IRT using 192Ir had a marked reduction in the need for repeat target lesion and vessel revascularization at 6 months, with the clinical benefit maintained at 3 years.

Cutting balloon angioplasty for the treatment of in-stent restenosis: a matched comparison with rotational atherectomy, additional stent implantation and balloon angioplasty

OBJECTIVES

The purpose of the study was to determine whether cutting balloon angioplasty (CBA) has advantages over other modalities in treatment of in-stent restenosis (ISR).

BACKGROUND

Controversies exist regarding optimal treatment for ISR. Recently, CBA emerged as a tool in management of ISR.

METHODS

A total of 648 lesions treated for ISR were divided into four groups according to the treatment strategy: CBA, rotational atherectomy (ROTA), additional stenting (STENT), and percutaneous transluminal coronary angioplasty (PTCA). Following the matching process, 258 lesions were entered into the analysis.

RESULTS

Baseline clinical and angiographic characteristics were similar among the groups (p = NS). Acute lumen gain was significantly higher in the STENT group (2.12 +/- 0.7 mm), whereas in the CBA group the gain was similar to one achieved following ROTA and following PTCA (1.70 +/- 0.6 vs. 1.79 +/- 0.5 mm and 1.56 +/- 0.7 mm, respectively; p = NS). The lumen loss at follow-up was lower for the CBA versus ROTA and versus STENT (0.63 +/- 0.6 vs. 1.30 +/- 0.8 mm and 1.36 +/- 0.8 mm, respectively; p < 0.0001), yielding a lower recurrent restenosis rate (20% vs. 35.9% and 41.4%, respectively; p < 0.05). By multivariate analysis, CBA (odds ratio [OR] = 0.17; confidence interval [CI], 0.06 to 0.51; p = 0.001) and diffuse restenosis type at baseline (OR = 2.07; CI, 1.15 to 3.71; p = 0.02) were identified as predictors of target lesion revascularization.

CONCLUSIONS

We conclude that CBA is a safe and efficient technique for treatment of ISR, with immediate results similar to atheroablation and better clinical and angiographic outcomes at follow-up. This approach might be implemented as a viable option in management of focal ISR and to prepare diffuse ISR for brachytherapy treatment.

Percutaneous and surgical interventions for in-stent restenosis: long-term outcomes and effect of diabetes mellitus

OBJECTIVE

We examined long-term outcomes of patients with in-stent restenosis (ISR) who underwent different percutaneous interventions at the discretion of individual operators: balloon angioplasty (BA), repeat stent or rotational atherectomy (RA). We also examined long-term outcomes of patients with ISR who underwent coronary artery bypass surgery (CABG).

BACKGROUND

In-stent restenosis remains a challenging problem, and its optimal management is still unknown.

METHODS

Symptomatic patients (n = 510) with ISR were identified using cardiac catheterization laboratory data. Management for ISR included BA (169 patients), repeat stenting (117 patients), RA (107 patients) or CABG (117 patients). Clinical outcome events of interest included death, myocardial infarction, target vessel revascularization (TVR) and a combined end point of these major adverse cardiovascular events (MACE). Mean follow-up was 19+/-12 months (range = 6 to 61 months).

RESULTS

Patients with ISR treated with repeat stent had significantly larger average post-procedure minimal lumen diameter compared with BA or RA (3.3+/-0.4 mm vs. 3.0+/-0.4 vs. 2.9+/-0.5, respectively, p < 0.05). Incidence of TVR and MACE were similar in the BA, stent and RA groups (39%, 40%, 33% for TVR and 43%, 40%, 33% for MACE, p = NS). Patients with diabetes who underwent RA had similar outcomes as patients without diabetes, while patients with diabetes who underwent BA or stent had worse outcomes than patients without diabetes. Patients who underwent CABG for ISR, mainly because of the presence of multivessel disease, had significantly better outcomes than any percutaneous treatment (8% for TVR and 23% for MACE).

CONCLUSIONS

In this large cohort of patients with ISR and in the subset of patients without diabetes, long-term outcomes were similar in the BA, repeat stent and RA groups. Tissue debulking with RA yielded better results only in diabetic patients. Bypass surgery for patients with multivessel disease and ISR provided the best outcomes.