Long-term clinical follow-up after successful repeat percutaneous intervention for stent restenosis

The effect of composite PHB coating on the biological properties of a magnesium based alloy

Magnesium alloys have been widely investigated as biodegradable cardiovascular temporal implants due to their better mechanical properties and biocompatibility, but the rapid degradation limited its application. In this study, the anodic oxidation-Cu structure was used to improve the adhesive strength and stability between poly-β-hydroxybutyrate (PHB) and magnesium alloys, and the effects of anodic oxidation magnesium alloys with copper film and PHB film (MACP) on human umbilical vein endothelial cells (HUVECs), blood compatibility and antibacterial properties were investigated in this research. As the result, the MACP structure had a stable structure and better corrosion resistance, and significant antibacterial properties. The coating would not affect the original excellent biocompatibility of the magnesium alloy. It was indicated that MACP was a potential surface modification strategy for vascular stents candidate material.

Comparison of 2-year outcomes of repeated second-generation drug-eluting stent implantation for focal-type versus nonfocal-type in-stent restenosis

BACKGROUND

Second-generation drug-eluting stents (DES) have been used widely to treat DES in-stent restenosis (ISR), which remains a clinical challenge. Knowledge of the outcomes of repeated second-generation DES implantation for focal versus nonfocal-type ISR is still missing.

METHODS

In the current study, 254 patients with DES-ISR were divided into focal or nonfocal groups according to their ISR angiographic types. All patients with ISR lesions included in the current study received second-generation DES. Treatment modalities for both groups were similar without any systematic bias toward either group. The primary endpoint of the study was the occurrence of major adverse cardiac events (MACEs) over a 2-year follow-up period. MACEs were defined as cardiac death, myocardial infarction, and target lesion revascularization.

RESULTS

The nonfocal-type group showed significantly greater incidence of MACEs than the focal-type group (38.3 vs. 24.1%; P=0.03), in which the occurrence of target lesion revascularization was more pronounced (32.3 vs. 18.4%; P=0.02). However, this group showed a higher incidence of type B2/C lesions (69.5 vs. 41.4%; P<0.01), with longer lesion length, and received significantly more and longer reimplanted stents than the focal-type group. Cox regression analysis indicated that nonfocal-type ISR was an independent predictor of MACEs (odds ratio 2.134, 95% confidence interval 1.173-3.884; P=0.014) after adjusting for all significant variables.

CONCLUSION

In the current study, second-generation DES is more effective in the treatment of focal-type DES-ISR than nonfocal-type ISR in terms of the occurrence of MACEs. Nonfocal-type ISR is an independent predictor of MACEs after the treatment of DES-ISR with second-generation DES.

Low-frequency low energy ultrasound combined with microbubbles induces distinct apoptosis of A7r5 cells

The present study aimed to investigate whether low frequency low energy ultrasound combined with microbubbles induces apoptotic cell death of A7r5 rat aortic vascular smooth muscle cells, and to identify the possible mechanisms underlying this effect. Ultrasonic waves (45 kHz with 0.3 Wcm2 of intensity for 0, 10, 20 and 30 sec) were used together with different dosages of SonoVue™ microbubbles (0, 14, 28, 42 and 56 µl), respectively. The cell viability and apoptotic rate were determined by trypan blue staining immediately following treatment and flow cytometry 24 h thereafter. The treatment conditions resulting in the lowest amount of necrosis, highest apoptotic rate and lowest microbubble dosage was selected for the US+MB group, which was treated with ultrasound combined with microbubbles. The cell proliferation 24 h following treatment was determined and western blot analysis was applied to examine the expression of apoptosis‑associated proteins, B-cell lymphoma 2 (Bcl‑2) and Bcl-2-associated X (Bax). The harmonic acoustic pressure amplitude was measured to obtain the cavitation intensity. The combination of 20 sec ultrasound irradiation and 14 µl SonoVue™ was selected as the treatment conditions for the US+MB group. The results demonstrated that both ultrasound alone (the US group) and in combination with microbubbles significantly inhibited the proliferation of A7r5 cells compared with that of the control (P<0.01), and the suppression in the US+MB group was significantly greater (P<0.01). The apoptotic rate in A7r5 cells induced by this combination treatment (16.62±0.93%) was significantly higher than that in the control (3.93±0.39%; P<0.01) and US (6.88±1.87%; P<0.01) groups. Treatment with ultrasound combined with microbubbles increased the expression of Bax and decreased the ratio of Bcl‑2/Bax compared with those in the control and US groups. The cavitation induced by ultrasound combined with microbubble treatment was more intense than that by ultrasound alone. The results demonstrated that the cell death and apoptosis of A7r5 cells were associated with ultrasound duration and microbubble dosage. Low frequency ultrasound combined with microbubbles induced apoptosis in A7r5 cells through the upregulation of Bax and the downregulation of the Bcl‑2/Bax ratio, where the cavitation effect may have an important role.

Nanocarriers for tracking and treating diseases

Site directed drug delivery with high efficacy is the biggest challenge in the area of current pharmaceuticals. Biodegradable polymer-based controlled release nanoparticle platforms could be beneficial for targeted delivery of therapeutics and contrast agents for a myriad of important human diseases. Biodegradable nanoparticles, which can be engineered to load multiple drugs with varied physicochemical properties, contrast agents, and cellular or intracellular component targeting moieties, have emerged as potential alternatives for tracking and treating human diseases. In this review, we will highlight the current advances in the design and execution of such platforms for their potential application in the diagnosis and treatment of variety of diseases ranging from cancer to Alzheimer's and we will provide a critical analysis of the associated challenges for their possible clinical translation.

Current advances in research and clinical applications of PLGA-based nanotechnology

Co-polymer poly(lactic-co-glycolic acid) (PLGA) nanotechnology has been developed for many years and has been approved by the US FDA for the use of drug delivery, diagnostics and other applications of clinical and basic science research, including cardiovascular disease, cancer, vaccine and tissue engineering. This article presents the more recent successes of applying PLGA-based nanotechnologies and tools in these medicine-related applications. It focuses on the possible mechanisms, diagnosis and treatment effects of PLGA preparations and devices. This updated information will benefit to both new and established research scientists and clinical physicians who are interested in the development and application of PLGA nanotechnology as new therapeutic and diagnostic strategies for many diseases.

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.

Outcomes of second revascularization procedures after stent implantation

Drug-eluting stents (DES) reduce subsequent revascularization procedures. Although randomized trials have compared DES to brachytherapy and balloon angioplasty (PTCA) for in-stent restenosis, few long-term comparisons have been made to bare metal stents (BMS) or bypass surgery (CABG), particularly following second procedures. We sought to assess the association between revascularization modality and long-term clinical outcomes of patients receiving a second procedure for coronary artery disease. Between January 2000 and July 2005, 4,666 consecutive patients underwent initial coronary stent implantation (DES or BMS). From this population we identified 569 patients undergoing a second target vessel revascularization (DES, BMS, PTCA or CABG). Outcomes were assessed at 6, 12, and 24 months after the second procedure, with follow-up through September 2006. Adjusted cumulative incidence rates were calculated using inverse probability weighted estimators. We found that at 24 months, there were no significant differences in death or myocardial infarction for PTCA, BMS, DES, and CABG (17.7%, 14.9%, 7.5%, and 10.2%, p = 0.26[3dfl]). DES patients had lower rates of death or myocardial infarction or third target vessel procedures than patients receiving PTCA (14.6% vs. 30.0%, p = 0.01) and BMS (14.6% vs. 42.2%, p < 0.01), but rates similar to CABG patients (14.6% vs. 14.6%, p = 0.99). For patients undergoing a second revascularization procedure, PTCA, BMS, DES, and CABG are associated with a similar risk of death or nonfatal myocardial infarction. DES and CABG are associated with lower rates of third revascularization procedures compared to PTCA and BMS. Further studies are needed to determine the optimum application for CABG vs. DES as a second or third revascularization procedure.

Endothelial dysfunction and restenosis following percutaneous coronary intervention

BACKGROUND

Restenosis remains an important limitation of PCI. Although local factors such as small vessel diameter and systemic factors such as diabetes explain some of its incidence, it nevertheless also occurs in low-risk patients. We hypothesize that endothelial dysfunction may be an independent risk factor in some of these cases.

METHODS

20 patients who had previously undergone PCI were studied at cardiac catheterization (10 with restenotic lesions were matched to 10 without restenosis). Infusion of multiple concentrations of acetylcholine (ACh) and nitroglycerine (GTN) were made via a 3F infusion catheter into the target artery. Following infusion, changes in diameter of segments proximal and distal to the PCI site were measured.

RESULTS

There was a significant impairment in endothelium-dependent dilatation at the maximal dose of acetylcholine in those with restenosis compared to those without restenosis, both proximal and distal to the stented area (proximal; 11.5+/-7.0% versus -20.9+/-9.0% p<0.001, distal; 12.0+/-3.1% versus -17.8+/-8.1% p<0.001), but there was no difference in the response to GTN. There was a significant correlation between the endothelium-dependent dilatation response and the percent restenosis (r=-0.65, p=0.003).

CONCLUSIONS

Coronary endothelium-dependent dilatation is reduced in subjects with restenosis in arterial segments separate from the stented lesion. This supports a hypothesis that endothelial dysfunction contributes to the development of restenosis, following percutaneous coronary intervention.

Symptomatic failure after sirolimus-eluting stent implantation: a rare but challenging condition

BACKGROUND

Limited information is available regarding restenosis after implantation of a sirolimus-eluting stent (SES).

OBJECTIVE

To report on angiographic characteristics, clinical presentation and treatment of this particularly complex type of coronary lesion.

METHODS AND RESULTS

A total of 1424 SES were implanted in 1159 patients (average 1.2 per patient) for chronic or acute coronary syndromes in the University Hospital of Siena (Siena, Italy), which is a tertiary centre. Symptomatic in-SES restenosis was observed in 26 patients (2.2%) at 10+/-5 months (median eight months, range four to 23 months) following the initial intervention. In-SES restenosis was associated with stable angina in 16 patients, acute myocardial infarction in three patients and unstable angina in seven patients. Two patients had restenosis in two separate SES. Conditions often associated with in-SES restenosis included treatment of chronic total occlusion, geographic miss or in-stent restenosis during the index procedure. Among the first 20 patients, those with focal, in-body SES (type Ic) restenosis received balloon-only angioplasty, and patients with other patterns received repeat SES implantation. Clinical and angiographic follow-up (average 16+/-7 months) recorded one death (noncardiac) in the balloon-only group and four cases of unstable angina (three due to relapsing in-SES restenosis in the balloon-only group and the fourth due to a de novo lesion). Follow-up quantitative angiography showed a higher incidence of binary restenosis after balloon-only treatment (57% versus 17%; P<0.05), as well as higher lumen loss and loss index (P<0.05).

CONCLUSIONS

Restenosis after SES implantation occurs more commonly in a focal pattern in-body or at the proximal edge of the stent. Repeat SES implantation appears to be a safer and more effective therapeutic choice than balloon-only angioplasty.

Endovascular Treatment of In-Stent Restenosis After Carotid Artery Stenting: Immediate and Midterm Results

PURPOSE

To evaluate the immediate and midterm outcome and analyze the debris captured after repeat endovascular intervention for the treatment of in-stent restenosis after carotid artery stenting (CAS).

METHODS

Thirty-one consecutive patients (27 men; mean age 63.7+/-13.0 years, range 53- 81) underwent repeat endovascular intervention (balloon angioplasty and provisional stenting) for the treatment of 32 in-stent restenoses following CAS.

RESULTS

Procedural success was achieved in all patients. An additional stent was implanted in 10 (31%) cases. No procedural complication was observed. Filter analysis was performed in 17 (53%) procedures; on 12 (71%), macroscopically visible material was captured. The histomorphometric analysis performed on 6 (19%) filters showed fibrin nets entrapping erythrocytes, leucocytes, platelets, and in 2 cases, fibrous hypercellular tissue fragments. At 30 days and during follow-up (mean 17+/-5 months), no deaths, transient ischemic attacks, or strokes were observed. In 1 (3.1%) patient, asymptomatic recurrence of ISR was found on Doppler ultrasonography and successfully treated with balloon angioplasty.

CONCLUSION

Repeat endovascular intervention using balloon angioplasty with provisional stenting and routine cerebral protection appears to be a feasible, safe, and clinically effective strategy for the treatment of in-stent restenosis after CAS.

Hyperplasia suppression by Ho:YAG laser intravascular irradiation in rabbit

The proliferation of smooth muscle cells (SMCs) was suppressed in denudated rabbit aorta by holmium-yttrium-aluminum-garnet (Ho:YAG) laser intravascular irradiation. This study was dedicated to determine the applicability of the Ho:YAG laser irradiation on chronic restenosis after balloon angioplasty. The proliferation of SMCs in denudated rabbit aortas was suppressed in vivo 6 weeks after the laser irradiation of 20 pulses with 60 mJ per pulse. To investigate the mechanisms of this in vivo effect, the death of SMCs by the Ho:YAG laser-induced bubble collapse pressure was studied in vitro. No significant cell death attributed to this pressure was found. We conclude that the suppression of the proliferation of SMCs in vivo might not be caused by a reduction in density of SMCs induced by the collapse in pressure. We submit that the suppression of SMC proliferation in vivo could be caused by the bubble expansion pressure and/or heat induced by the laser irradiation.

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.

Long-term results (three to five years) of the Restenosis Intrastent: Balloon angioplasty versus elective Stenting (RIBS) randomized study

OBJECTIVES

We sought to analyze the very late outcomes of patients treated for in-stent restenosis (ISR) according to treatment allocation and 10 prespecified variables.

BACKGROUND

Long-term results (>2 years) of patients with ISR undergoing repeat coronary interventions are not well established.

METHODS

The Restenosis Intrastent: Balloon angioplasty versus elective Stenting (RIBS) randomized study compared these two strategies in 450 patients with ISR. A detailed systematic protocol was used for late clinical follow-up.

RESULTS

At one-year follow-up (100% of patients), the event-free survival was similar in the two groups (77% stent implantation [ST] arm, 71% balloon angioplasty [BA] arm, log-rank p = 0.19). Additional long-term clinical follow-up (median 4.3 years, range 3 to 5 years) was obtained in 98.6% of patients. During this time 22 additional patients died (9 ST arm, 13 BA arm), 7 suffered a myocardial infarction (3 ST arm, 4 BA arm), 23 required coronary surgery (11 ST arm, 12 BA arm), and 9 underwent repeat coronary interventions (4 ST arm, 5 BA arm) (nonexclusive events). At four years the event-free survival was 69% in the ST arm and 64% in the BA arm (log-rank p = 0.21). Among the 10 prespecified variables, vessel size > or = 3 mm had a major influence on the clinical outcome at four years, with better results in the ST group (hazard ratio 0.51, 95% confidence interval 0.3 to 0.89, p = 0.016).

CONCLUSIONS

Patients with ISR undergoing repeat interventions have a significant event rate at late follow-up. Continued medical surveillance should be continued after one year. Patients with large vessels have a better outcome after repeat stenting.

Serial intravascular ultrasound comparison of the extent and distribution of intimal hyperplasia six months after stent implantation for de novo versus in-stent restenosis lesions

The aim of this study was to compare intimal hyperplasia (IH) growth at 6 months in patients with de novo lesions treated with stents versus IH regrowth in patients with treated in-stent restenosis. Intravascular ultrasound was performed after intervention and at the 6-month follow-up visit as part of a standardized protocol across several clinical trials. At 6 months, the lumen was larger in the de novo group (mean lumen cross-sectional area [CSA] 6.31 +/- 2.2 vs 4.48 +/- 1.9 mm(2), p = 0.0001; minimum lumen CSA 4.2 +/- 1.8 vs 2.59 +/- 1.5 mm(2), p = 0.0001). However, the total increase in the mean IH CSA volume was the similar in the de novo and ISR groups (2.89 +/- 1.6 vs 2.64 +/- 1.94 mm(2), respectively; p = 0.11). We found that IH regrowth in restented in-stent restenosis lesions was similar to that in de novo stent implantation and that the final lumen CSA was an important component of in-stent restenosis recurrence.

Comparison of angiographic and clinical outcomes between rotational atherectomy and cutting balloon angioplasty followed by radiation therapy with a rhenium 188-mercaptoacetyltriglycine-filled balloon in the treatment of diffuse in-stent restenosis

BACKGROUND

Rotational atherectomy (RA) and cutting balloon angioplasty (CBA) have been shown to effectively dilate in-stent restenosis (ISR). It is not known, however, which of these technique, when followed by beta-radiation, is more effective. Therefore, we performed a prospective randomized study comparing RA and CBA before beta-radiation therapy for diffuse ISR.

METHODS

Patients with diffuse ISR were randomly assigned to receive RA (group 1, n = 58) or CBA (group 2, n = 55) before beta-radiation therapy with a rhenium 188-mercaptoacetyltriglycine-filled balloon, with the radiation dose being 18 Gy at a depth of 1.0 mm into the vessel wall. The primary end point was angiographic restenosis at 6 months, and the secondary end point was major adverse cardiac events (myocardial infarction, death, target lesion revascularization) at 9 months.

RESULTS

The 2 groups were similar in baseline characteristics. Mean lesion length was 21.0 +/- 11.2 mm in group 1 and 20.8 +/- 10.2 mm in group 2 (P = .77). Radiation was delivered successfully to all patients. We obtained 6-month angiographic follow-up in 90 patients (80%). The rates of angiographic restenosis were 14.9% (7 of 47) in group 1 and 14.0% (6 of 43) in group 2 (P = .89). No patient experienced myocardial infarction or death during the 9-month follow-up period. Rates of target lesion revascularization or major adverse cardiac events were 3.4% in group 1 and 3.6% in group 2 (P = .94) during the 9-month follow-up.

CONCLUSIONS

Either RA or CBA, followed by beta-radiation using a rhenium 188-mercaptoacetyltriglycine-filled balloon, is equally safe and effective for diffuse ISR in 6-month angiographic and 9-month clinical outcomes.

Comparison of angiographic and clinical outcomes between rotational atherectomy versus balloon angioplasty followed by radiation therapy with a rhenium-188-mercaptoacetyltriglycine-filled balloon in the treatment of diffuse in-stent restenosis

BACKGROUND

The purpose of this study was to compare the efficacy of rotational atherectomy (RA) with simple balloon angioplasty, prior to beta-radiation therapy with a rhenium-188-mercaptoacetyltriglycine (188Re-MAG3)-filled balloon for diffuse in-stent restenosis (ISR).

METHODS

After completing 50 cases with RA prior to beta-radiation (Group I), we performed optimal balloon angioplasty followed by beta-radiation in the next 53 consecutive patients (Group II) for the treatment of diffuse ISR. The radiation dose was 15 Gy at a depth of 1.0 mm into the vessel wall.

RESULTS

The baseline clinical and angiographic characteristics were similar between the two groups. The mean length of the lesion was 25.6+/-12.7 mm in Group I and 22.9+/-8.6 mm in Group II (p=0.26). Radiation was successfully delivered to all patients, with a mean irradiation time of 179+/-55 s. The 6-month angiographic restenosis rate was 10% (5/50) in Group I versus 33% (17/51) in Group II (p=0.007). No adverse event including myocardial infarction, death, or stent thrombosis occurred during the 1-year follow-up period. The risk of a target lesion revascularization or a major adverse cardiac event was significantly lower in Group I than in Group II (two patients in Group I vs. nine patients in Group II; OR, 0.20; 95% CI, 0.04-0.96; p=0.04).

CONCLUSION

Concomitant treatment with rotational atherectomy and beta-irradiation using a 188Re-MAG3-filled balloon for diffuse ISR has a synergistic effect, in terms of 6-month angiographic restenosis and 1-year cardiac event-free survival.

Efficient inhibition of in-stent restenosis by controlled stent-based inhibition of elastase: a pilot study

PURPOSE

It is proposed that local elastase inhibition could suppress the extracellular matrix (ECM) degradation and subsequent smooth muscle cell migration and limit subsequent in-stent restenosis. This study evaluated the effect of stent-based controlled elastase inhibition on restenosis after stent implantation in a rabbit model.

MATERIALS AND METHODS

Biodegradable microspheres containing the potent elastase inhibitor alpha-1-antitrypsin (AAT) were prepared. Daily release of AAT from the microspheres was confirmed in vitro. The microspheres were loaded into stents with an abluminal polymer reservoir. Implantation of the stent with AAT microspheres and blank microspheres (control) was performed in the abdominal aortae of six rabbits in each group. After stent deployment, all stents were overdilated to 125% diameter. Stent-implanted arteries were harvested after 7 days (n = 3 each) or 28 days (n = 3 each). To assess the effect of local delivery of AAT, elastase activity and elastin content of the stent-implanted aortae were analyzed. As an endpoint, intima-to-media (I/M) ratio was determined in the 7-day and 28-day specimens.

RESULTS

Significant inhibition of elastase was confirmed in treated vessels versus controls at 7 days after stent implantation (P < .05). This reduction in elastase activity was sufficient to afford early and late reduction of in-stent neointima. Plaque progression in the 28-day specimens decreased to 67% with elastase inhibition relative to controls (P < .05).

CONCLUSION

Stent-based controlled release of elastase inhibitor may significantly reduce ECM degradation and might limit in-stent restenosis.

Long-term outcomes after treatment of diffuse in-stent restenosis with rotational atherectomy followed by beta-radiation therapy with a 188Re-MAG3-filled balloon

BACKGROUND

Intracoronary radiation therapy for in-stent restenosis has been demonstrated to reduce restenosis and major adverse cardiac events. However, long-term angiographic and clinical outcomes after beta radiation therapy have not been sufficiently evaluated.

METHODS

We evaluated the long-term angiographic and clinical outcomes of 50 consecutive patients who had received beta-radiation therapy with a 188Re-MAG3-filled balloon after rotational atherectomy for diffuse in-stent restenosis (lesion length>10 mm) in native coronary arteries. The radiation dose was 15 Gy at a depth of 1.0 mm into the vessel wall.

RESULTS

The mean lesion length was 25.6+/-12.7 mm. Radiation was delivered successfully to all patients without any procedural or in-hospital complications. At the 6-month angiogram, the restenosis rates was 10% (5/50). There were no major adverse cardiac events (MACE), such as death, myocardial infarction, and target lesion revascularization (TLR) by 6-month follow-up. Long-term clinical follow-up data were obtained in all patients during 30.1+/-4.5 months. No myocardial infarction and one noncardiac death occurred during follow-up. Two-year follow-up angiogram was performed in 26 (58%) of 45 patients who showed a patent radiation segment at the 6-month angiogram. Significant narrowing of diameter stenosis of more than 50% occurred in 6 (23%) of 26 patients between 6 and 24 months after beta-radiation. Late TLR was performed in 6 patients. The rate of 30-month death-free survival and MACE-free survival were 98.0+/-2.0% and 86.9+/-5.0%.

CONCLUSION

Beta-radiation using a 188Re-MAG3-filled balloon after rotational atherectomy is associated with favorable long-term angiographic and clinical outcomes.

Nocturnal Oxygen Desaturation as a Predictive Risk Factor for Coronary Restenosis After Coronary Intervention Serial Quantitative Coronary Angiography Study

BACKGROUND

Sleep-disordered breathing may affect coronary artery disease, so patients treated by percutaneous transluminal coronary angioplasty were studied to investigate the relationship between nocturnal oxygen desaturation (NOD) and the loss index.

METHODS AND RESULTS

The nocturnal oxygen desaturation index (ODI) was determined by means of a pulse oximeter in 35 patients with coronary artery disease treated by stent placement. The patients were divided into 3 groups according to ODI: <5 events/h (group N, n=6), between 5 and 14 events/h (group A, n=19), and >or=15 events/h (group B, n=10). The relationship between the ODI and loss index was examined in each group. The loss index, 0.27+/-0.23 in group N, 0.30+/-0.27 in group A, and 0.70+/-0.32 in group B, differed significantly between groups N and B (p=0.007). In all patients, the loss index showed a significant positive correlation with the ODI (R=0.585, p=0.002).

CONCLUSIONS

These findings suggest that NOD may be an important contributor to coronary restenosis in patients treated with stent placement.

Sirolimus- and paclitaxel-eluting stents in comparison with balloon angioplasty for treatment of in-stent restenosis

This study evaluated the acute and follow-up effectiveness of sirolimus-eluting stents (SESs) and nonpolymer-based paclitaxel-eluting stents (PESs) in comparison will balloon angioplasty for treatment of complex in-stent restenosis (ISR) lesions. Drug-eluting stents have been demonstrated to be highly effective for treatment of de novo lesions. The use of drug-eluting stents for treatment of complex ISR is less well defined. Eighty one lesions with in-stent restenosis (lesion length < 30 mm in a native coronary artery) were treated with either PTCA alone (n = 26 lesions in 25 patients), PES (n = 27 lesions in 24 patients; Achieve, Cook; 3,1 mug paclitaxel/mm(2) nonpolymer-based coating), SES (n = 28 lesions in 28 patients; Cypher, Cordis; 140 mug sirolimus/cm(2) metal surface area). Nine-month MACE rates were 32%, 8%, and 14% (all due to repeated revascularization procedures, except one death in the SES group) in the PTCA, PES, and SES group, respectively. Postintervention minimal lumen diameter in stent was significantly greater in the SES and the PES group in comparison with the PTCA group (2.37 +/- 0.26, 2.54 +/- 0.42, 1.78 +/- 0.23 mm; P < 0.001). At 6-month angiographic follow-up, late loss in stent was 0.77 +/- 0.45, 0.43 +/- 0.53, and 0.29 +/- 0.52 mm for the PTCA, PES, and SES group, respectively (P = 0.005). In-lesion restenosis rate was 61% for the PTCA group, 20% for the PES group, and 13% for the SES group (P = 0.042). The implantation of SES as well as nonpolymer PES proved to be effective for treatment of ISR. The combination of improved acute gain and reduced late loss results in a significantly improved angiographic follow-up result in comparison with PTCA.

Stent-based Controlled Release of Intravascular Angiostatin to Limit Plaque Progression and In-Stent Restenosis

PURPOSE

To evaluate the importance of angiogenesis in plaque progression after stent placement, this study examines stent-based controlled delivery of the antiangiogenic agent, angiostatin, in a rabbit model.

MATERIALS AND METHODS

Controlled release biodegradable microspheres delivering angiostatin or polymer-only microspheres (polylactic-co-glycolic-acid-polyethylene glycol; PLGA/PEG) were loaded in channeled stents, anchored, and deployed in the aorta of adult New Zealand white rabbits (n = 6 animals per group, three each per time point). The stented aortas were harvested at 7 days and 28 days and evaluated for neovascularization, local inflammation, vascular smooth muscle cell proliferation, and in-stent plaque progression.

RESULTS

At 7 days, neovascularization was significantly decreased in the angiostatin groups (1.6 +/- 1.6 neovessels per mm(2) plaque) versus the control group (15.4 +/- 2.6 neovessels per mm(2) plaque; P =.00081), as were local inflammation where angiostatin-treated groups demonstrated significantly lower macrophage recruitment per cross section (34.9 +/- 4.9 cells per cross section) relative to the control group (55.2 +/- 3.84 cells per cross section; P =.0037). And a significant decrease in the overall vascular smooth muscle cell proliferation (143.8 +/- 26.3 Ki-67 positive cells per mm(2)) relative to the control group (263.2 +/- 16.6 Ki-67 positive cells per mm(2); P =.00074). At both 7 and 28 days, in-stent plaque progression in the angiostatin groups was successfully limited relative to the control group by 54% (0.255 +/- 0.019% of cross section; P =.00016) and 19% (1.981 +/- 0.080; P =.0033) respectively and resulted in reduction of in-stent restenosis relative to the control group.

CONCLUSION

Angiostatin-eluting stents may limit neovascularity after arterial implantation, offer insight into in-stent restenosis, and allow future refinement of bioactive stent designs and clinical strategies, particularly in light of evidence that intimal smooth muscle cells may in part be marrow-derived.

[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.

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.

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.

Brachytherapy for in-stent restenosis in general interventional practice: a single institution's experience using four radiation devices

BACKGROUND

The effectiveness of brachytherapy for the treatment of in-stent restenosis (ISR) has been established in a number of large randomized controlled trials. Efficacy of this therapy in general population is less well established.

METHODS AND MATERIALS

We report our experience of 207 patients, 236 coronary lesions, treated with brachytherapy between November 2000 and November 2002. All commercially available brachytherapy devices, as well as one investigational device, were utilized. This cohort was followed over 9 months and clinical outcomes were obtained with subsequent analysis of patient and lesion-specific characteristics.

RESULTS

Average treatment age was 62.5 years; 73% were male and the most frequent presentation was unstable angina (74%). All patients had successful delivery of radiation, with no in-hospital deaths. Novoste BetaCath device was used for 163 (65%) lesions, Cordis Checkmate for 56 (24%) lesions, Interventional Therapies device in 13 (8%) lesions, and Guidant Galileo in 4 lesions (3%). At a mean follow-up of 9.1 months, 78.7% were free of major adverse cardiac event (MACE). Twenty-one patients required repeat PTCA (10.1%), 19 had CABG (9.2%), 3 had MI (1.4%), and there was 1 death (0.5%). Unadjusted MACE rates for each device were 21% for Novoste, 28% for Checkmate, 8% for Interventional Therapies, and 50% for Galileo. Lesion length, minimal lumen diameter, renal failure, diabetes, and smoking did not predict treatment failure; only age was inversely correlated with MACE (P=.002).

CONCLUSION

When applied across a spectrum of patients, lesions, and devices, brachytherapy retains its effectiveness with outcomes similar to those reported in randomized clinical trials.

Re-angioplasty of in-stent restenosis versus balloon restenoses—a matched pair comparison

BACKGROUND

Despite different biological mechanisms involved in the restenotic process of in-stent restenosis and restenosis after balloon angioplasty alone, the occurrence of a second restenosis has been reported in the same range. There are no data available comparing the outcome after re-angioplasty of such lesions. We analyzed in a matched pair comparison the clinical outcome and angiographic long-term result of patients with balloon angioplasty of a first in-stent restenosis versus patients with balloon re-angioplasty of a first balloon restenosis.

METHODS

Both groups consisted of 74 lesions matched by treated vessel, lesion location differentiated in proximal and non-proximal, and angiographic appearance of coronary artery disease differentiated in singular stenosis, diffuse or mixed pattern. Clinical follow-up was 100%. Angiographic follow-up was 78.4% after median 174 days.

RESULTS

Angiographic restenosis rate in matched pairs of patients (n=46/74) was significantly higher in the balloon restenosis group (41.3%, n=19/46) compared to the in-stent restenosis group (21.7%, n=10/46, p<0.042). There was no death or myocardial infarction. After clinical follow-up, target lesion revascularization rate was significantly lower in the in-stent restenosis group compared to the balloon restenosis group (12.1%, n=9/74 versus 27.0%, n=20/74; difference between groups 14.9%, 95% confidence interval 2.0-27.3%, p<0.023). Multivariate logistic regression analysis revealed as predictors for a second restenosis unstable angina pectoris, non-proximal lesion, restenosis after balloon angioplasty and the occurrence of the first restenosis within 90 days after initial intervention.

CONCLUSION

Clinical and angiographic outcome after balloon angioplasty of a first in-stent restenosis was significantly better compared with balloon re-angioplasty of a first balloon restenosis.

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.

Gamma radiation for in-stent restenosis: effect of lesion length on angiographic and clinical outcomes

The relation between lesion length and effectiveness of gamma radiation treatment (gamma-RT) has not been well described. We evaluated the acute and long-term outcome according to baseline lesion length in 130 patients treated with (192)Ir in the Washington Radiation for In-Stent Restenosis Trial; 44 (35.5%) had baseline short in-stent restenosis (ISR) lesions (length < 15 mm) and 80 (64.5%) long ISR lesions (length > or = 15 mm). At 6-month follow-up after gamma-RT, the short ISR group had larger lumen dimensions and lower late loss than the long ISR group. Restenosis rate was significantly higher in patients with long ISR for both the placebo (74% vs. 39%; P = 0.01) and the gamma-RT arm (31% vs. 5.3%; P = 0.04). gamma-RT significantly improved the angiographic outcome in the short-lesion groups but had the more pronounced effect on the reduction of clinical events after treatment of long ISR group. Lesion length remains a powerful predictor of recurrent ISR and clinical events after treatment of ISR even with gamma-RT.

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.

Outcomes of optimal or “stent-like”balloon angioplasty in acutemyocardial infarction: the CADILLAC trial

OBJECTIVES

We sought to compare outcomes between patients with acute myocardial infarction (AMI) undergoing percutaneous transluminal coronary angioplasty (PTCA) with an optimal or "stent-like" result versus patients who underwent routine stent placement.

BACKGROUND

Recent studies in patients with AMI undergoing stent implantation have suggested that PTCA may no longer be a relevant treatment modality for stent eligible lesions. However, whether routine stent placement is superior or necessary when an optimal PTCA or "stent-like" result is achieved is unknown.

METHODS

In the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial, 2,082 patients with AMI were randomly assigned to undergo PTCA alone, PTCA + abciximab, stenting alone, or stenting + abciximab. Outcomes were compared in patients achieving an optimal acute PTCA result (residual core laboratory diameter stenosis <30% without significant dissection) versus those assigned to routine stenting.

RESULTS

Optimal PTCA was achieved in 40.7% of patients randomized to balloon angioplasty, including 38.5% and 42.7% assigned to PTCA alone and PTCA + abciximab, respectively. Ischemic target vessel revascularization (TVR) at 30 days occurred more frequently after optimal PTCA than routine stenting (5.1% vs. 2.3%, p = 0.007). The one-year composite adverse event rate (death, reinfarction, disabling stroke, or TVR) was greater after optimal PTCA than routine stenting (21.9% vs. 13.8%, p < 0.001), driven largely by increased rates of ischemic TVR (19.1% vs. 9.1%, p < 0.001); no significant differences were present in the rates of death, reinfarction, or disabling stroke between the two groups. Angiographic restenosis also was more common with optimal PTCA than routine stenting (36.2% vs. 22.2%, p = 0.003). Even a post-PTCA diameter stenosis of <20% (realized in 12% of patients) did not result in outcomes equivalent to stenting.

CONCLUSIONS

Even if an optimal result is achieved after primary PTCA in AMI, early and late outcomes can be further improved with routine stent implantation.

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.

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.

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.

Human in-stent restenosis tissue obtained by means of coronary atherectomy consists of an abundant proteoglycan matrix with a paucity of cell proliferation

BACKGROUND

In-stent restenosis (ISR) is a shortcoming of percutaneous coronary revascularization. Although neointimal cell proliferation is suspected to be the cause of this problem, little histological characterization of this tissue or data on cell replication exist. The purpose of this study was to examine the histologic features and proliferation profile of coronary ISR tissue derived from atherectomy procedures performed on patients with clinical evidence of ISR.

METHODS

ISR tissue retrieved by means of atherectomy from 20 coronary lesions was subjected to histomorphological analyses and immunocytochemistry as a means of examining proteoglycan expression. Cell proliferation was assessed with 2 sensitive markers of replication, in situ hybridization for histone 3 messenger RNA expression and immunocytochemistry for Ki-67 expression.

RESULTS

The ISR atherectomy specimens consisted primarily of smooth muscle cells, with occasional focal collections of inflammatory cells and organizing thrombus. All specimens had low levels of interstitial collagen and an abundant proteoglycan matrix, with biglycan being overexpressed more commonly than decorin. Cell proliferation was found in only 1 of 20 specimens (2 cells).

CONCLUSION

Established ISR lesions contained an abundant proteoglycan matrix and a paucity of proliferating cells. Future therapeutic strategies for ISR should include targeting extracellular matrix production.

Results of the Jostent coronary stent graft implantation in various clinical settings: procedural and follow-up results

The Jostent coronary stent graft (CSG) is composed of a PTFE layer sandwiched between two stainless steel stents, initially introduced for the treatment of coronary perforations and aneurysms with excellent results. By providing a mechanical barrier, this stent design also may be beneficial in the treatment of complex ulcerated lesions and in-stent restenosis by preventing debris protrusion and neointimal proliferation through the stent struts. To evaluate the safety and efficacy of this stent graft, we implanted 78 CSGs in 70 patients for a broad range of indications, including coronary perforations, aneurysms, degenerated saphenous vein grafts, complex lesions, and in-stent restenosis. The primary angiographic success rate (95.9%) was high, and using intravascular ultrasound (IVUS) guidance during stent implantation and high inflation pressures (19.3 +/- 3.2 atm), stent expansion with optimal symmetry was achieved in 94.7%. One limitation of the Jostent CSG was the side-branch occlusion rate (18.6%) and the resulting non-Q-wave infarction rate in seven cases (mean CK elevation, 238 U/l), acute Q-wave MI in two cases, and transient ventricular fibrillation in one patient after occlusion of the proximal RCA side branch without further complications. Subacute stent thrombosis occurred in four cases (5.7%) 7 to 70 days after stent implantation, despite using combined antiplatelet therapy with aspirin (ASA), ticlopidine, and/or clopidogrel for 30 days. Angiographic follow-up was available in 56 patients (80.0%) after a mean of 159 +/- 49 days, and follow-up IVUS was available in 38 cases. The overall restenosis rate (> 50% diameter stenosis) was 31.6% manifest primarily as edge restenosis (29.8% stent edge vs. 8.8% stent center; P < 0.001). IVUS examinations showed a minimal late lumen loss of 0.4 +/- 2.2 mm(2) within the center of the stent graft vs. 3.2 +/- 2.3 mm(2) at the stent edges (P < 0.001). The restenosis rate in the prespecified subgroups was 33.3% for saphenous vein grafts (2/6 lesions), 30.0% in complex lesions (6/20 lesions), and 38.5% (10/26 lesions) for the treatment of in-stent restenosis. Implantation of the Jostent CSG is feasible and safe, even in complex lesion subsets, and is associated with high primary success rates provided major side branches are avoided. The use of this stent may require an extended time course of antiplatelet therapy. Frequent focal stent edge renarrowing influences the overall restenosis rate. However, in treatment of complex in-stent restenosis and vein graft lesions, stent grafts may offer benefit over conventional therapies. Covered stents such as the JoMed coronary stent graft may become essential for bailout treatment of coronary perforations.

Long-term clinical outcome after implantation of medium Palmaz (biliary) stents in very large native coronary arteries

Intracoronary stenting has been shown to improve acute and long-term clinical results compared with coronary angioplasty. However, clinical outcome after medium Palmaz biliary (PB) stent implantation in very large native coronary arteries (> 4 mm in diameter) is unknown. This study evaluated restenosis and long-term clinical outcome after PB stenting in large native coronary arteries. Between June 1993 and December 1998, 55 patients with 56 lesions were treated with PB stents. Intracoronary stent deployment was successful in all 56 vessels attempted (100%). The mean stenosis was reduced from 65% +/- 10% to 4% +/- 14%. In 48 of the 56 vessels (86%), vessel size was greater than 4.0 mm in diameter and the mean reference vessel diameter was 4.73 +/- 0.7 mm after stenting. Angiographic success was achieved in 100%. Five patients had postprocedural cardiac enzyme elevation. There was no periprocedural death, emergency coronary artery bypass surgery, repeat target lesion revascularization, or acute stent thrombosis. Long-term clinical follow-up at mean of 28 +/- 15 months was obtained in 96% of the patients. Clinical restenosis rate occurred in 18% of ostial (6/34) and 0% of nonostial (0/22) lesions (P < 0.0001) with an overall clinical restenosis rate of 11%. Repeat angioplasty were performed in these six patients. There were three cardiac and three noncardiac deaths. The overall event-free survival at 1 and 3 years was 92% +/- 4% and 80% +/- 6%, respectively. PB stent implantation in very large native coronary arteries can be performed with a high degree of procedural success and low in-hospital complications. The long-term clinical outcome of patients undergoing PB stenting is associated with excellent event-free survival. However, stenting of ostial lesions remains as an important factor for restenosis even in very large coronary artery stenting.

The initial course of in-stent restenosis influences the response to vascular brachytherapy

BACKGROUND

Vascular brachytherapy (VBT) reduces the rate of recurrence of in-stent restenosis (ISR) by inhibiting intimal proliferation. However, the rate of cell proliferation, reflected by the speed of ISR development, is variable in ISR lesions and might influence the responsiveness of ISR to radiation. The aim of this study was to determine the influence of the initial ISR course on the clinical outcome of patients undergoing VBT.

METHODS

In 1165 patients treated for ISR with VBT in the WRIST studies, we determined the time for ISR (time between initial stent implantation and restenosis), the time for VBT treatment (time between stent implantation and VBT), and previous ISR treatment with conventional strategies. Target lesion revascularization (TLR) at 6 months was available in all patients.

RESULTS

Previous ISR treatment did not influence the result of VBT (TLR was 17% vs. 16% without previous angioplasty). Time to ISR influences the outcome of patients undergoing VBT; TLR decreased when ISR occurred later. TLR was 18.2%, 16.7%, and 11.1% when time to ISR was <90, 90-2700, and >270 days, respectively, P=.03. Early ISR (time for ISR <90 days) is a factor for radiation failure (OR=2.1, P<.05). In patients with early ISR, TLR is lower when VBT is delayed; TLR was 11% if performed 90 days after stent implantation as compared to 22% if VBT is performed early (<90 days), P<.05.

CONCLUSION

The course of ISR development affects the long-term efficacy of VBT. Early restenosis remains a factor of treatment failure in the VBT era. Delaying VBT beyond 90 days after stent implantation reduces the rate of subsequent revascularization in these patients.

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.

Definition of a moving gross target volume for stereotactic radiation therapy of stented coronary arteries

PURPOSE

To measure the effect of cardiac motion on coronary artery stent position during the cardiac cycle as a first step toward exploring the feasibility of stereotactic external beam radiation therapy targeted at restenotic stented coronary arteries.

METHODS AND MATERIALS

The three-dimensional (3D) position of eight coronary artery stents in 8 patients immobilized in a stereotactic body frame was studied noninvasively by single-breathhold ECG-gated multislice spiral computed tomography (MSCT) during 10 retrospectively selected phases, equally distributed throughout the R-R interval of consecutive cardiac cycles. The volume encompassing all measured 3D positions of the stent was measured.

RESULTS

Stent volumes measured by MSCT closely agreed with measurements by quantitative coronary angiography (r > 0.99). The mean of the maximum 3D stent center of mass displacement between any two phases during the cardiac cycle for all eight coronary arteries was 7.5 mm (range 3.3-20.5 mm) in the lateral direction, 8.6 mm (range 2.7-21.6 mm) in the ventrodorsal direction, and 8.2 mm (range 2.5-19.7 mm) in the craniocaudal direction. As was anticipated, the volume encompassing all measured 3D positions of the stent represented only a fraction of the whole heart volume in all patients, i.e., less than 0.6%.

CONCLUSIONS

ECG-gated MSCT allowed the measurement of the volume encompassing multiphase 3D positions of coronary artery stents during the cardiac cycle. This volume, a measure of the cardiac motion effect on coronary artery stent position during the cardiac cycle, represents a moving gross target for stereotactic external beam radiation therapy.

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.