Angioscopic evaluation of neointima coverage: sirolimus drug-eluting stent versus bare metal stent

Arterial Healing 10 Months After Implantation of an Ultrathin-Strut, Biodegradable-Polymer, Sirolimus-Eluting Stent - An Angioscopic Study

Background: The Orsiro^TM ultrathin-strut, biodegradable-polymer, sirolimus-eluting stent (O-SES) has specific characteristics regarding its components and has demonstrated comparable clinical outcomes compared with durable-polymer, drug-eluting stents (DES). However, arterial repair following deployment of the O-SES has not been elucidated to date.

Methods and Results: Using data from the Kansai Rosai Hospital database between November 2010 and September 2020, we analyzed coronary angioscopy (CAS) findings a mean (±SD) of 10±2 months after implantation of an O-SES, a durable-polymer everolimus-eluting stent (Xience^TM; X-EES), or a biodegradable-polymer everolimus-eluting stent (Synergy^TM; S-EES). Neointimal coverage (NIC), yellow color intensity of the stented segment, and the incidence of thrombus adhesion were compared between the O-SES (66 stents from 42 patients), X-EES (119 stents from 87 patients), and S-EES (132 stents from 88 patients). NIC was significantly thinner for the O-SES than S-EES (P<0.001), but was similar between the O-SES and X-EES (P=0.25). Yellow color intensity was significantly greater for the O-SES than X-EES (P<0.001), but similar between the O-SES and S-EES (P=0.51). The incidence of thrombus adhesions was similar in all 3 groups.

Conclusions: O-SES and X-EES resulted in similar inhibition of NIC and both resulted in a thinner NIC than with S-EES. In addition, O-SES exhibited a similar degree of thrombus adhesion as the other DES, suggesting similar thrombogenicity.

Clinical Importance of the LDL-C/Apolipoprotein B Ratio for Neointimal Formation after Everolimus-Eluting Stent Implantations

AIMS

Smaller low-density lipoprotein (LDL) particle size has been suggested to result in the development of endothelial dysfunction, atherosclerosis, and in-stent restenosis (ISR); however, little is known regarding the impact of the LDL particle size on the neointima formation leading to ISR after everolimus-eluting stent (EES) implantation.

METHODS

In this study, we have included 100 patients to examine the relationship between an LDL-C/apolipoprotein B (Apo B) ≤ 1.2, reportedly representing the LDL particle size, and the neointimal characteristics using optical coherence tomography (OCT) and coronary angioscopy (CAS) during the follow-up coronary angiography (CAG) period (8.8±2.5 months) after EES implantation. We divided them into two groups: LDL-C/Apo B ≤ 1.2 group (low LDL-C/Apo B group, n=53) and LDL-C/Apo B ＞1.2 group (high LDL-C/Apo B group, n=47).

RESULTS

The low LDL-C/Apo B group had a significantly larger neointimal volume (12.8±5.3 vs. 10.3±4.9 mm³, p=0.021) and lower incidence of a neointimal homogeneous pattern (71 vs. 89 %), higher incidence of a neointimal heterogeneous pattern (25 vs. 9 %) (p=0.006) and higher prevalence of macrophage accumulation (9 vs. 2 %) (p=0.030) as assessed via OCT, and, as per the CAS findings, a higher prevalence of yellow grade ≥ 2 (grade 2; adjusted residual: 2.94, grade 3; adjusted residual: 2.00, p=0.017) than the high LDL-C/Apo B group.

CONCLUSIONS

A low LDL-C/Apo B ratio was found to be strongly associated with neointimal proliferation and neointimal instability evidenced chronically by OCT and CAS. An LDL-C/Apo B ≤ 1.2 will be of aid in terms of identifying high-risk patients after EES implantation.

The comparison of early healing 1-month after PCI among CoCr-everolimus-eluting stent (EES), biodegradable polymer (BP)-EES and BP-sirolimus-eluting stent: Insights from OFDI and coronary angioscopy

Background

Third-generation stents with abluminal biodegradable polymer (BP) might facilitate early healing. Therefore, we compared early healing between second-generation and third-generation stents using coronary angioscopy (CAS) and optical frequency domain imaging [OFDI].

Methods

We prospectively enrolled 30 consecutive patients with stent implantation for acute coronary syndrome (cobalt‑chromium [CoCr] everolimus-eluting stent [EES] [n = 10], BP-EES [n = 10], and BP-sirolimus eluting stent [SES] [n = 10]). All patients underwent CAS and OFDI 1 month after initial percutaneous coronary intervention. On OFDI, the stent coverage (SC), thrombus, and peri-strut low intensity area (PLIA) were assessed. CAS findings were recorded for the grade of SC, grade of yellow color (YC), and grade of the thrombus (TG).

Results

On OFDI, the incidences of any thrombus at the 1-month follow-up were 70%, 80%, and 80% in the CoCr-EES, BP-EES, and BP-SES groups, respectively. The percentage of coverage was comparable among the groups (CoCr-EES 79.8 vs. BP-EES 79.9 vs. BP-SES 80.1%, P = 0.96). However, the number of struts with PLIA was numerically higher in the BP-SES group than in the CoCr-EES and BP-EES groups (46.4 ± 25.1 vs. 21.6 ± 13.2 vs. 22.0 ± 7.2%, P = 0.08). In the CoCr-EES, BP-EES, and BP-SES groups, mean grades of SC were 1.25 ± 0.5, 1.25 ± 0.5, and 0.85 ± 0.70 (P = 0.60); mean grades of YC were 0.75 ± 0.5, 0.80 ± 0.45, and 0.88 ± 0.37 (P = 0.65), and mean grades of TG were 1.00 ± 1.00, 1.20 ± 0.83, and 0.88 ± 0.64 (P = 0.75), respectively.

Conclusion

Third-generation stents are not inferior to second-generation stents regarding stent coverage. However, PLIA on OFDI was often observed with BP-SESs, indicating involvement of the fibrin component.

Drug-eluting stents versus bare-metal stents for acute coronary syndrome

BACKGROUND

Approximately 3.7 million people died from acute coronary syndrome worldwide in 2012. Acute coronary syndrome, also known as myocardial infarction or unstable angina pectoris, is caused by a sudden blockage of the blood supplied to the heart muscle. Percutaneous coronary intervention is often used for acute coronary syndrome, but previous systematic reviews on the effects of drug-eluting stents compared with bare-metal stents have shown conflicting results with regard to myocardial infarction; have not fully taken account of the risk of random and systematic errors; and have not included all relevant randomised clinical trials.

OBJECTIVES

To assess the benefits and harms of drug-eluting stents versus bare-metal stents in people with acute coronary syndrome.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS, SCI-EXPANDED, and BIOSIS from their inception to January 2017. We also searched two clinical trials registers, the European Medicines Agency and the US Food and Drug Administration databases, and pharmaceutical company websites. In addition, we searched the reference lists of review articles and relevant trials.

SELECTION CRITERIA

Randomised clinical trials assessing the effects of drug-eluting stents versus bare-metal stents for acute coronary syndrome. We included trials irrespective of publication type, status, date, or language.

DATA COLLECTION AND ANALYSIS

We followed our published protocol and the methodological recommendations of Cochrane. Two review authors independently extracted data. We assessed the risks of systematic error by bias domains. We conducted Trial Sequential Analyses to control the risks of random errors. Our primary outcomes were all-cause mortality, major cardiovascular events, serious adverse events, and quality of life. Our secondary outcomes were angina, cardiovascular mortality, and myocardial infarction. Our primary assessment time point was at maximum follow-up. We assessed the quality of the evidence by the GRADE approach.

MAIN RESULTS

We included 25 trials randomising a total of 12,503 participants. All trials were at high risk of bias, and the quality of evidence according to GRADE was low to very low. We included 22 trials where the participants presented with ST-elevation myocardial infarction, 1 trial where participants presented with non-ST-elevation myocardial infarction, and 2 trials where participants presented with a mix of acute coronary syndromes.Meta-analyses at maximum follow-up showed no evidence of a difference when comparing drug-eluting stents with bare-metal stents on the risk of all-cause mortality or major cardiovascular events. The absolute risk of death was 6.97% in the drug-eluting stents group compared with 7.74% in the bare-metal stents group based on the risk ratio (RR) of 0.90 (95% confidence interval (CI) 0.78 to 1.03, 11,250 participants, 21 trials/22 comparisons, low-quality evidence). The absolute risk of a major cardiovascular event was 6.36% in the drug-eluting stents group compared with 6.63% in the bare-metal stents group based on the RR of 0.96 (95% CI 0.83 to 1.11, 10,939 participants, 19 trials/20 comparisons, very low-quality evidence). The results of Trial Sequential Analysis showed that we did not have sufficient information to confirm or reject our anticipated risk ratio reduction of 10% on either all-cause mortality or major cardiovascular events at maximum follow-up.Meta-analyses at maximum follow-up showed evidence of a benefit when comparing drug-eluting stents with bare-metal stents on the risk of a serious adverse event. The absolute risk of a serious adverse event was 18.04% in the drug-eluting stents group compared with 23.01% in the bare-metal stents group based on the RR of 0.80 (95% CI 0.74 to 0.86, 11,724 participants, 22 trials/23 comparisons, low-quality evidence), and Trial Sequential Analysis confirmed this result. When assessing each specific type of adverse event included in the serious adverse event outcome separately, the majority of the events were target vessel revascularisation. When target vessel revascularisation was analysed separately, meta-analysis showed evidence of a benefit of drug-eluting stents, and Trial Sequential Analysis confirmed this result.Meta-analyses at maximum follow-up showed no evidence of a difference when comparing drug-eluting stents with bare-metal stents on the risk of cardiovascular mortality (RR 0.91, 95% CI 0.76 to 1.09, 9248 participants, 14 trials/15 comparisons, very low-quality evidence) or myocardial infarction (RR 0.98, 95% CI 0.82 to 1.18, 10,217 participants, 18 trials/19 comparisons, very low-quality evidence). The results of the Trial Sequential Analysis showed that we had insufficient information to confirm or reject our anticipated risk ratio reduction of 10% on cardiovascular mortality and myocardial infarction.No trials reported results on quality of life or angina.

AUTHORS' CONCLUSIONS

The current evidence suggests that drug-eluting stents may lead to fewer serious adverse events compared with bare-metal stents without increasing the risk of all-cause mortality or major cardiovascular events. However, our Trial Sequential Analysis showed that there currently was not enough information to assess a risk ratio reduction of 10% for all-cause mortality, major cardiovascular events, cardiovascular mortality, or myocardial infarction, and there were no data on quality of life or angina. The evidence in this review was of low to very low quality, and the true result may depart substantially from the results presented in this review.More randomised clinical trials with low risk of bias and low risks of random errors are needed if the benefits and harms of drug-eluting stents for acute coronary syndrome are to be assessed properly. More data are needed on the outcomes all-cause mortality, major cardiovascular events, quality of life, and angina to reduce the risk of random error.

WITHDRAWN: Drug-eluting stents versus bare metal stents for angina or acute coronary syndromes

This review 'topic' has been included in work being carried out as part of a Health Technology Assessment commissioned by the National Institute for Clinical Excellence in England and Wales. Details of this research is available via www.nice.org.uk.

The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the HTA programme, NICE, NIHR, NHS or the Department of Health.

The review has been split into 2 reviews that will be published as "Drug‐eluting stents versus bare‐metal stents for stable ischaemic heart disease" and "Drug‐eluting stents versus bare‐metal stents for acute coronary syndrome".

The editorial group responsible for this previously published document have withdrawn it from publication.

Drug-eluting stent thrombosis in the treatment of chronic total coronary occlusions: incidence, presentation and related factors. Data from the CIBELES trial

INTRODUCTION AND OBJECTIVES

The aim of this study was to analyze the incidence of drug-eluting stent thrombosis (sirolimus or everolimus) in patients with chronic total coronary occlusions (CTO) and to determine its clinical implications and related factors.

METHODS

Data from the 12-month follow-up of the 207 patients included in the CIBELES trial with CTO were analyzed.

RESULTS

Stent thrombosis occurred in three patients, two definite and one probable (overall thrombosis rate: 1.4%). However, there were no cases of death or Q-wave myocardial infarction. In univariate analysis, patients with a higher incidence of stent thrombosis were those in whom the target vessel was the left anterior descending, who had single-vessel disease, were assigned to treatment with sirolimus-eluting stents, and those with smaller minimum luminal diameter immediately after the procedure. In multivariate analysis, the only independent predictor of stent thrombosis was minimal luminal diameter immediately after the procedure.

CONCLUSIONS

The rate of drug-eluting stent thrombosis in patients with CTO is relatively low (1.4%). The only independent predictor of stent thrombosis in this context was minimal luminal diameter after the procedure and the clinical presentation was in all cases relatively benign.

Prevention of stent thrombosis: challenges and solutions

Stent thrombosis is an uncommon but serious complication which carries with it significant mortality and morbidity. This review analyzes the entity of stent thrombosis from a historical and clinical perspective, and chronicles the evolution of this condition through the various generations of stent development, from bare metal to first-generation, second-generation, and third-generation drug-eluting stents. It also delineates the specific risk factors associated with stent thrombosis and comprehensively examines the literature related to each of these risks. Finally, it highlights the preventative strategies that can be garnered from the existing data, and concludes that a multifactorial approach is necessary to combat the occurrence of stent thrombosis, with higher risk groups, such as patients with ST segment elevation myocardial infarction, meriting further research.

Remodeling pattern is related to the degree of coronary plaque regression induced by pitavastatin: a sub-analysis of the TOGETHAR trial with intravascular ultrasound and coronary angioscopy

This study aimed to clarify the relationships between arterial remodeling patterns and plaque volume regression or stabilization. The TOGETHAR trial is a prospective open-label trial designed to assess coronary plaque regression and stabilization with multiple plaque imaging modalities following 52 weeks of pitavastatin treatment (2 mg/day). Coronary plaques were observed in 46 patients with both angioscopy and intravascular ultrasound at baseline and after 52 weeks of drug treatment. We divided these patients into three groups according to their remodeling indices (RI). Group P consisted of patients with a baseline RI >1.05, Group M of patients with a baseline RI of 0.95-1.05, and Group N of patients with a baseline RI <0.95 and then evaluated differences in coronary plaque volume changes and yellow grade among the three groups. In the positive remodeling group, whose remodeling index (RI) exceeded 1.05 at baseline, RI and percent atheroma volume (PAV) were significantly reduced (RI 1.14 ± 0.07 to 1.05 ± 0.10, p = 0.010, PAV 47.3 ± 8.3 to 45.3 ± 7.3 mm(3), p = 0.048). There was no relationship between baseline RI and the change in yellow grade of plaque. RI increased without significant change of PAV or a decrease in lumen volume in group N, with RI below 0.95 at baseline. Plaques with positive remodeling were more likely to have plaque volume regression by pitavastatin than those without in patients with coronary artery disease. Moreover, plaques with positive and negative remodeling were changed into those with intermediate remodeling by pitavastatin. Pitavastatin might induce not only plaque regression or stabilization, but also conformational normalization of vessel structure.

Angioscopic assessment of peri-stent contrast staining following drug-eluting stent implantation

BACKGROUND

Peri-stent contrast staining (PSS) has been recognized as a predictor of late stent thrombosis following drug-eluting stent (DES) implantation. However, the intravascular conditions at PSS sites remain unclear.

METHODS AND RESULTS

We evaluated 10 patients (median age 72 years, 80% male) with stable angina pectoris by coronary angioscopy. The patients had a total of 11 DES implantations (5 sirolimus-eluting stents; 4 paclitaxel-eluting stents; 2 everolimus-eluting stents) that showed PSS. Neointimal coverage (NIC), presence of thrombus, and yellow plaques underneath the stent were compared between PSS and non-PSS sites for each stent. NIC was graded as: grade 0, struts exposed; grade 1, struts bulging into the lumen, although covered; grade 2, struts embedded by neointima, but translucent; grade 3, struts fully embedded and invisible. Mean follow-up was 394±206 days (median: 289). NIC grade was lower at PSS sites (P=0.021) with 8 out of 11 stents (73%) having grade 0. Angioscopy detected a thrombus more frequently at PSS sites than at non-PSS sites (64% vs. 9%, P=0.012). Yellow plaques tended to be more significant at PSS sites than at non-PSS sites (82% vs. 45%, P=0.091).

CONCLUSIONS

The angioscopic findings suggest high thrombogenicity at PSS sites.

A higher colour grade yellow plaque was detected at one year after implantation of an everolimus-eluting stent than after a zotarolimus-eluting stent

OBJECTIVE

Neoatherosclerosis or atherosclerosis progression is one of the mechanisms of long-term stent failure. Yellow plaque detected by angioscopy has been associated with advanced atherosclerosis and the future risk of a coronary event. We compared the yellow colour of the stented segment between zotarolimus-eluting stents (ZES) and everolimus-eluting stents (EES) at 1 year after implantation.

DESIGN

Cross-sectional study.

PATIENTS

Consecutive patients underwent angioscopic examination 1 year after the implantation of ZES (n=45) or EES (n=45) at a de novo native coronary lesion.

MAIN OUTCOME MEASURES

The maximum yellow colour grade (grade 0-3) of the stented segment, maximum and minimum neointima coverage grade (grade 0-2) and the presence of thrombus were examined. The neointima heterogeneity index was calculated as maximum - minimum coverage grade.

RESULTS

Maximum yellow colour grade was higher in EES than in ZES (1.3±0.9 vs 0.4±0.8, p<0.001) and maximum (2.0±0.2 vs 1.2±0.5, p<0.001) and minimum (1.5±0.6 vs 0.7±0.5, p<0.001) coverage grade was higher in ZES than in EES. The neointima heterogeneity index was not different between ZES and EES (0.4±0.5 vs 0.5±0.6, p=0.42). The incidence of thrombus was very low and was not different between ZES and EES (2% vs 4%, p=0.55).

CONCLUSIONS

Although both ZES and EES had good healing with homogeneous neointima coverage and a low incidence of thrombus, EES had more advanced atherosclerosis as shown by the presence of higher grade yellow plaque than ZES at 1 year after implantation.

Comparisons of detailed arterial healing response at seven months following implantation of an everolimus- or sirolimus-eluting stent in patients with ST-segment elevation myocardial infarction

BACKGROUND

The difference of arterial healing response following everolimus-eluting stent (EES) or sirolimus-eluting stent (SES) implantation in patients with ST-segment elevated myocardial infarction (STEMI) has not been compared in detail.

METHODS

Thirty-five patients with STEMI were randomly implanted with an EES or SES (23 EES, 12 SES). At seven months, neointimal thickness (NIT) and strut malapposition were evaluated by optical coherence tomography (OCT) and the grade and heterogeneity of neointimal coverage (NIC) and development of intra-stent thrombi were evaluated by angioscopy.

RESULTS

No significant differences were noted in clinical events experienced by the two groups, although one patient with an EES died following a papillary muscle rupture and one patient with a SES experienced sub-acute stent thrombosis. On OCT, although the EES implants showed a greater NIT than the SES implants (94.8 ± 88.8 μm vs 65.6 ± 63.3 μm, P<0.0001), both the EES and SES showed an excellent suppression of neointimal proliferation in the culprit lesion of STEMI. The frequency of uncovered and malapposed struts of EES was significantly lower than that of SES (2.7% vs. 15.7%, P<0.0001, 0.7% vs. 2.3%, P<0.0001, respectively). The ratio of stents fully covered with neointima of EES group was significantly higher than that of SES group (P=0.04). Angioscopic analysis also showed greater dominant NIC grade with homogenous NIC in EES than in SES (P=0.03, P=0.0002, respectively). The incidence of massive intra-stent thrombus of EES was lower than that of SES (P=0.05).

CONCLUSION

For patients with STEMI, EES may promote better arterial healing response than SES.

Incidence and clinical impact of stent fracture after everolimus-eluting stent implantation

BACKGROUND

Stent fracture (SF) after drug-eluting stent implantation has recently become an important concern because of its potential association with in-stent restenosis and stent thrombosis. However, the incidence and clinical impact of SF after everolimus-eluting stent implantation remain unclear.

METHODS AND RESULTS

A total of 1035 patients with 1339 lesions undergoing everolimus-eluting stent implantation and follow-up angiography 6 to 9 months after index procedure were analyzed. SF was defined as complete or partial separation of the stent, as assessed by plain fluoroscopy or intravascular ultrasound during follow-up. We assessed the rates of SF and major adverse cardiac events, defined as cardiac death, myocardial infarction, stent thrombosis, and clinically driven target lesion revascularization within 9 months. SF was observed in 39 of 1339 lesions (2.9%) and in 39 of 1035 patients (3.8%). Ostial stent location and lesions with hinge motion, tortuosity, or calcification were independent predictors of SF. The rate of myocardial infarction and target lesion revascularization were significantly higher in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018 and 25.6% versus 2.0%; P<0.001, respectively). Stent thrombosis was more frequently observed in the SF group than in the non-SF group (5.1% versus 0.4%; P=0.018). Major adverse cardiac events within 9 months were significantly higher in the SF group than in the non-SF group (25.6% versus 2.3%; P<0.001).

CONCLUSIONS

SF after everolimus-eluting stent implantation occurs in 2.9% of lesions and is associated with higher rate of major adverse cardiac events, driven by higher target lesion revascularization and stent thrombosis.

Detection of high-risk atherosclerotic plaque: report of the NHLBI Working Group on current status and future directions

The leading cause of major morbidity and mortality in most countries around the world is atherosclerotic cardiovascular disease, most commonly caused by thrombotic occlusion of a high-risk coronary plaque resulting in myocardial infarction or cardiac death, or embolization from a high-risk carotid plaque resulting in stroke. The lesions prone to result in such clinical events are termed vulnerable or high-risk plaques, and their identification may lead to the development of pharmacological and mechanical intervention strategies to prevent such events. Autopsy studies from patients dying of acute myocardial infarction or sudden death have shown that such events typically arise from specific types of atherosclerotic plaques, most commonly the thin-cap fibroatheroma. However, the search in human beings for vulnerable plaques before their becoming symptomatic has been elusive. Recently, the PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) study demonstrated that coronary plaques that are likely to cause future cardiac events, regardless of angiographic severity, are characterized by large plaque burden and small lumen area and/or are thin-cap fibroatheromas verified by radiofrequency intravascular ultrasound imaging. This study opened the door to identifying additional invasive and noninvasive imaging modalities that may improve detection of high-risk atherosclerotic lesions and patients. Beyond classic risk factors, novel biomarkers and genetic profiling may identify those patients in whom noninvasive imaging for vulnerable plaque screening, followed by invasive imaging for risk confirmation is warranted, and in whom future pharmacological and/or device-based focal or regional therapies may be applied to improve long-term prognosis.

Thromboresistant and endothelialization effects of dopamine-mediated heparin coating on a stent material surface

Heparinization of surfaces has proven a successful strategy to prevent thrombus formation. Inspired by the composition of adhesive proteins in mussels, the authors used dopamine to immobilize heparin on a stent surface. This study aimed to assess the thromboresistant and endothelialization effects of dopamine-mediated heparin (HPM) coating on a stent material surface. The HPM was synthesized by bonding dopamine and heparin chemically. Cobalt-chromium (Co-Cr) alloy disks were first placed in the HPM solution and applied to surface stability then underwent thromboresistant tests and human umbilical vein endothelial cells (HUVEC) cytotoxicity assays. The results showed not only thromboresistant activity and a stable state of heparin on the surfaces after investigation with toluidine blue and thrombin activation assay but also proliferation of HUVEC in vitro. Studies on animals showed that the HPM-coated stent has no obvious inflammation response and increasing of restenosis rate compared to the bare metal stent (BMS) indicating good biocompatibility as well as safety in its in vivo application. Moreover, improving the endothelial cell (EC) proliferation resulted in a higher strut-covering rate (i.e., endothelialization) with shuttle-shaped EC in the HPM-coated stent group compared to that of the BMS group. These results suggest that this facile coating approach could significantly promote endothelialization and offer greater safety than the BMS for its much improved thromboresistant property. Moreover, it may offer a platform for conjugating secondary drugs such as anti-proliferative drugs.

Diagnostic value of myocardial SPECT to detect in-stent restenosis after drug-eluting stent implantation

Different angiographic patterns and restenosis rate may affect diagnostic value of single-photon emission computed tomography (SPECT) in the era of drug-eluting stents (DES). We aimed to determine the ability of myocardial SPECT to detect in-stent restenosis (ISR) in patients treated with DES compared to that of patients treated with bare metal stent (BMS). We evaluated 228 consecutive patients who underwent 6 months follow-up SPECT and coronary angiography (CAG) after stent implantation. In 228 patients, 354 vessels were treated with stent implantation (BMS, n = 105; DES, n = 249) and 65 (18.4%) vessels showed ISR (angiographic % diameter stenosis ≥ 50%) at the 6-month follow-up CAG. In patients with BMS-ISR (n = 37), restenosis was primarily diffuse (70.3%), whereas patients with DES-ISR (n = 28) exhibited more focal restenosis (53.6%, p = 0.028). The sensitivity and specificity of myocardial SPECT did not differ significantly between patients with BMS and those with DES (BMS vs. DES: sensitivity 56.8 vs. 39.3%, p = 0.163; specificity 72.1 vs. 76.5%, p = 0.460). Evaluation of 71 false positive and 33 false negative lesions showed that the most common cause of false-positive results in SPECT was the perfusion decrease which improved but not disappeared compared with the baseline (46 among 71 vascular territories). Despite different patterns of restenosis and ISR rates, the diagnostic value of SPECT did not differ between BMS and DES. Further study looking at ISR in larger number of patients and using other protocol such as Fleming-Harrington Redistribution Wash-in Washout may give additional information.

Very late stent thrombosis at 2.5 years after sirolimus-eluting stent implantation with prior angioscopic image of culprit lesion: A case report

Although very late stent thrombosis after drug-eluting stent implantation is a critical event, its cause has not been clarified. This is the first report of a case with very late stent thrombosis after drug-eluting stent implantation for which prior angioscopic image of the culprit lesion is available. A 54-year-old Japanese male patient with stable angina who received implantation of sirolimus-eluting stent at the culprit lesion and 1-year follow-up angiographic and angioscopic examinations came back with chest pain at rest at 2.5 years after the stent implantation. Very late stent thrombosis was diagnosed by emergent angiographic and angioscopic examinations and was treated by zotarolimus-eluting stent. One-year angiographic and angioscopic follow-up examinations after zotarolimus-eluting stent were performed. Angioscopy revealed uncovered stent strut, yellow plaques, and thrombus at 1-year follow-up after sirolimus-eluting stent implantation, and it confirmed the thrombotic occlusion inside the sirolimus-eluting stent at the time of emergent catheterization. This is a case of very late stent thrombosis in the drug-eluting stent where uncovered stent strut, yellow plaques, and thrombus had been detected by angioscopy 1.5 years before the onset. Those thrombogenic sources might be the cause of stent thrombosis.

Coronary angioscopy: current topics and future direction

Disruption of vulnerable plaque and following thrombus formation are considered the main cause of acute coronary syndrome (ACS). Intracoronary angioscopy is an endoscopic technology that allows direct visualization of the coronary artery lumen and provides detailed information regarding plaque morphology in patients with coronary artery disease. The color and morphology of coronary plaque under angioscopy observation are proposed to be determinants for plaque stability. Angioscopically yellow plaque represents a thin-cap fibroatheroma, and is associated with a higher incidence of disruption and thrombus formation, and may be associated with future acute coronary syndromes. To circumvent the subjectivity of color interpretation, various quantitative methods have been proposed for identifying vulnerable plaques. Superior to other coronary imaging techniques such as VH IVUS and optical coherence tomography, angioscopy has impressively high sensitivity and specificity in detection of intraluminal thrombus. Angioscopy can also be used as an adjunctive technique during catheter intervention by directly visualizing the thrombus, stent struts and proliferating neointima. The time course and pattern of neointima coverage, as seen by angioscopy, various among different stent systems. Angioscopic assessment of serial changes after stent implantation may have potential benefits on patient's management after coronary stenting.

Rationale and design of the randomized, multicenter EREMUS trial, a study that investigates how to achieve low restenosis and early reendothelialization after percutaneous coronary interventions

BACKGROUND

Drug eluting stent (DES) use has improved clinical outcome after percutaneous coronary interventions. However, DES-treated patients may have a higher risk of stent thrombosis, mainly due to uncorrect stent deployment or lack of reendothelialization. Thus, the availabilily of different approaches with comparable efficacy to DES, but higher safety, especially in bleeding-prone patients, have to be investigated.

STUDY DESIGN

The EREMUS is a multicenter open-label prospective randomized three-arm clinical trial that will investigate the efficacy of a paclitaxel coated balloon + an endothelial progenitor capture stent for the treatment of native coronary lesions, and compare it to a DES strategy, or the sole endothelial progenitor capture stent. An angiographic follow-up with optical coherence tomography analysis will be scheduled 9 months after index procedure. Noninferiority regarding the primary endpoint (late luminal loss) between study group and DES is hypothesized. All patients will undergo clinical follow-up until 24 months from index hospitalization.

CONCLUSIONS

The EREMUS trial will determine whether a composite approach with a paclitaxel coated balloon + an endothelial progenitor capture stent in coronary lesions at medium-to-high risk of restenosis will achieve similar results compared to DES regarding inhibition of intrastent proliferation; complete stent strut reendothelialization, a safety issue, will also be investigated.

Possible role of damaged neoendothelial cells in the genesis of coronary stent thrombus in chronic phase. A dye staining angioscopic study

The mechanism(s) underlying formation of coronary stent thrombus (ST) in chronic phase is yet unclear. Endothelial cells are highly antithrombotic, therefore, it is conceivable that neoendothelial cells (NECs) covering stent struts are damaged and cause ST. This study was performed to examine the role of damaged NECs covering coronary stent struts in the genesis of occlusive or nonocclusive ST in chronic phase.(1) Forty-four patients with acute coronary syndrome (17 females and 27 males) underwent dye-staining coronary angioscopy, using Evans blue which selectively stains damaged endothelial cells, 6 months after bare-metal stent (BMS) deployment. Neointimal coverage was classified into not covered (grade 0), covered by a thin layer (grade 1), and buried under neointima (grade 2) groups. (2) In 7 beagles, the relationships between neointimal thickness and ST were examined 6 months after BMS deployment. (3) The NECs on the struts were stained blue in 4 of 25 patients with grade 2 and in 11 of 20 patients with grade 0/1 (P < 0.05). ST was observed in none of the former and in 5 of the latter (P < 0.05). (4) In beagles, neointimal coverage was grade 0/1 when neointimal thickness was 80.2 ± 40.0 µm, whereas grade 2 when thickness was 184 ± 59.4 µm. ST was observed in 9 of 15 struts with neointimal thickness within 100 µm and in one of 17 struts with thickness over 100 µm (P < 0.05). ST arose from damaged NECs covering the stent struts. NECs may have been damaged due to friction between them and struts due to thin interposed neointima which might have acted as a cushion, resulting in ST.

Strut coverage and late malapposition with paclitaxel-eluting stents compared with bare metal stents in acute myocardial infarction: optical coherence tomography substudy of the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) Trial

BACKGROUND

The safety of drug-eluting stents in ST-segment elevation myocardial infarction (STEMI) continues to be debated. Pathological studies have demonstrated an association between uncovered struts and subsequent stent thrombosis. Optical coherence tomography can detect stent strut coverage in vivo on a micron-scale level. We therefore used optical coherence tomography to examine strut coverage in patients with STEMI treated with paclitaxel-eluting stents (PES) and bare metal stents (BMS).

METHODS AND RESULTS

In the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, patients with STEMI were randomized 3:1 to PES or BMS implantation. In a formal substudy, optical coherence tomography at 13 months was performed in 118 consecutive randomized patients (89 PES, 29 BMS) in whom 188 stents were assessed (146 PES and 42 BMS). A total of 44 139 stent struts were analyzed by an independent core laboratory blinded to stent assignment. The primary prespecified end point, the percentage of uncovered stent struts per lesion at follow-up, was 1.1 ± 2.5% in BMS lesions versus 5.7 ± 7.0% in PES lesions (P < 0.0001). Malapposed struts were observed in 0.1 ± 0.2% of BMS lesions versus 0.9 ± 2.1% of PES lesions (P = 0.0003). Percentage net volume obstruction was 36.0 ± 15.4% with BMS and 19.2 ± 11.3% with PES (P < 0.0001).

CONCLUSIONS

In patients with STEMI undergoing primary percutaneous coronary intervention, implantation of PES as compared with BMS significantly reduces neointimal hyperplasia but results in higher rates of uncovered and malapposed stent struts as assessed by optical coherence tomography at 13-month follow-up. Further studies are required to determine the clinical significance of these findings.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00433966.

Stent thrombosis

Intense investigation continues on the pathobiology of stent thrombosis (ST) because of its morbidity and mortality. Because little advance has been made in outcomes following ST, ongoing research is focused on further understanding predictive factors as well as ST frequency and timing in various patient subsets, depending upon whether a drug-eluting stent or bare-metal stent has been implanted. Although the preventive role of antiplatelet therapies remains unchallenged, new data on genomics and variability in response to antiplatelet therapy, as well as the effects of novel therapeutic agents and duration of therapy, have become available. The goal remains identification of patients at particularly increased risk of ST so that optimal prevention strategies can be developed and employed.

Angioscopic Evaluation of Neointimal Coverage of Coronary Stents

Drug-eluting stents (DES) reduce coronary restenosis significantly; however, late stent thrombosis (LST) occurs, which requires long-term antiplatelet therapy. Angioscopic grading of neointimal coverage of coronary stent struts was established, and it was revealed that neointimal formation is incomplete and prevalence of LST is higher in DES when compared to bare-metal stents. It was also observed that the neointima is thicker and LST is less frequent in paclitaxel-eluting and zotarolimus-eluting stents than in sirolimus-eluting stents. Many new stents were devised and they are now under experimental or clinical investigations to overcome the shortcomings of the stents that have been employed clinically. Endothelial cells are highly anti-thrombotic. Neo-endothelial cell damage is considered to be caused by friction between the cells and stent struts due to the thin neointima between them which might act as a cushion. Therefore, development of a DES that causes an appropriate thickness (around 100 μm) of the neointima is a potential option with which to prevent neo-endothelial cell damage and consequent LST while preventing restenosis.

Stabilization and regression of coronary plaques treated with pitavastatin proven by angioscopy and intravascular ultrasound--the TOGETHAR trial

BACKGROUND

Few studies have serially monitored the change of coronary plaque after statin therapy using multiple plaque imaging modalities.

METHODS AND RESULTS

A prospective open-label trial was performed to assess coronary plaque regression and stabilization following 52 weeks of pitavastatin treatment (2 mg/day). Coronary segments that included the most diseased plaque of 90 patients determined on angioscopy were analyzed using intravascular ultrasound (IVUS). The yellow grade of each plaque of 46 patients who had matched angioscopy and IVUS data was evaluated on angioscopy. Low-density lipoprotein-cholesterol (LDL-C) was reduced 34.5% (145.0+/-24.0 mg/dl to 93.6+/-22.6 mg/dl, P<0.001), and high-density lipoprotein cholesterol increased 17.8% (44.9+/-11.1 mg/dl to 51.9+/-11.7 mg/dl, P<0.001). Yellow grade decreased (2.9+/-0.8 to 2.6+/-0.7, P=0.040) during 52 weeks. The reduction of yellow grade was not correlated with the LDL-C level at 52 weeks or its change. The change of yellow grade was inversely correlated with maximum yellow grade at baseline. Percent atheroma volume on IVUS did not change during 52 weeks, but its change for 52 weeks was significantly correlated with LDL-C level at 52 weeks (Spearman's rank correlation coefficient 0.312, P=0.035).

CONCLUSIONS

Fixed dose pitavastatin stabilized vulnerable coronary plaques by the reduction of yellow grade without significant reduction of plaque volume. The stabilization and regression of atherosclerotic plaques by statin may differ, but both nonetheless contribute to the reduction of cardiovascular events (UMIN Clinical Trials Registry UMIN000001107).

Drug-eluting stents versus bare metal stents for angina or acute coronary syndromes

BACKGROUND

Coronary artery stents are tiny tubular devices used to 'scaffold' vessels open during percutaneous transluminal coronary angioplasty (PTCA). Restenosis (re-narrowing) of vessels treated with stents is a problem; in order to reduce restenosis, stents that elute drugs over time are now available. However these drug-eluting stents are more expensive and there is a need to assess their clinical benefits prior to recommending their use.

OBJECTIVES

To examine evidence from randomised controlled trials (RCTs) to assess the impact of drug eluting stents (DES) compared to bare metal stents (BMS) in the reduction of cardiac events.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 4), MEDLINE (1990 - April 2009) and EMBASE (1980 - January 2009) were searched. We carried out handsearching (electronic and manual) up to January 2008.

SELECTION CRITERIA

We included RCTs comparing DES with BMS used in conjunction with PTCA techniques in the review. Participants were adults with stable angina or acute coronary syndrome (ACS). We considered published and unpublished sources and included them if they reported outcome data of interest.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data, assessed trial quality assessment and checked decisions within the group. Data extraction included composite event rates (major adverse cardiac event, target vessel failure); death; acute myocardial infarction (AMI); target lesion revascularisation (TLR); target vessel revascularisation (TVR) and thrombosis. Data synthesis included meta-analysis of composite event rate, death, AMI and revascularisation rates, presented as odds ratios with 95% confidence intervals (CI) using a fixed-effect model. We assessed heterogeneity between trials.

MAIN RESULTS

We included more than 14,500 patients in 47 RCTs. There were no statistically significant differences in death, AMI or thrombosis between DES and BMS. For composite events, TLR and TVR reductions were evident with use of sirolimus, paclitaxel, everolimus, dexamethasone, zotarolimus and (to a limited extent) tacrolimus-eluting stents. These effects are demonstrated in the longer term follow up. Subgroup analyses (e.g. diabetics) largely mirrored these findings.

AUTHORS' CONCLUSIONS

Drug-eluting stents releasing sirolimus, paclitaxel, dexamethasone and zotarolimus reduce composite cardiac events. However, this reduction is due largely to reductions in repeat revascularisation rates as there is no evidence of a significant effect on rates of death, MI or thrombosis. The increased cost of drug-eluting stents and lack of evidence of their cost-effectiveness means that various health funding agencies are having to limit or regulate their use in relation to price premium.

Bare metal stent implantation for in-stent restenosis with a drug-eluting stent

Following the positioning of a bare metal stent (BMS) implant, a yellow plaque is healed with a reduction of the color grade and thrombogenicity, i.e. vulnerability by angioscopy in the chronic phase ("plaque sealing" of BMS; the "whitening effect" of BMS). However, we have reported that thrombus and yellow plaque increases at the drug-eluting stent (DES) site. A 71-year-old man underwent percutaneous coronary intervention using two DESs for a severe stenotic lesion in his right coronary artery. Follow-up coronary angiography (CAG) showed in-stent restenosis (ISR) at the stent-overlap site. We performed traditional balloon angioplasty, but follow-up CAG showed ISR again at the same position as the first restenosis. In angioscopic findings, the normal vessel wall was white, but the site of DES implantation was yellow and a yellow, soft, swelling neointimal proliferation-like vulnerable plaque was observed at the restenotic site. In expectation of the "whitening effect" of BMS, we implanted a new BMS. As anticipated, follow-up CAG showed no restenosis. Moreover, the angioscopic findings indicated a clean, white, neointimal proliferation-like stable plaque at the BMS implant site in the yellow vulnerable area of DES. The "BMS in DES" therapy should be considered one of the strategies for ISR of DES.

Coronary angioscopic evaluation for serial changes of luminal appearance after pharmacological and catheter interventions

Although preventive pharmacological therapies effectually reduce the risk of cardiovascular events, acute coronary syndrome (ACS) remains a leading cause of morbidity and mortality in our country, Japan. Disruption of atherosclerotic vulnerable plaques and flow-limiting thrombus formation in non-stent segments of native coronary arteries are considered a main mechanism of ACS. In addition, stent thrombosis originating from implanted metallic coronary stents, so-called vulnerable stents, occasionally appears as ACS in the clinical settings. Coronary angioscopy is a unique imaging modality permitting direct visualization of luminal structures, such as atherosclerotic plaque, thrombus, stent struts, and proliferating neointima. On the basis of accumulated angioscopic findings, intense yellow plaques and stents without neointimal coverage are considered vulnerable plaques and vulnerable stents, respectively. In contrast, morphological disappearance of vulnerable plaques or vulnerable stents by pharmacological and trans-catheter therapies imply stabilization of the plaques or stents. Hence, angioscopic assessment for vulnerability (or stability) of atherosclerotic plaques and implanted stents might be useful for risk classification in the future events of ACS. To evaluate serial changes of coronary lumen after pharmacological and catheter interventions using angioscopy might also provide important information on potential benefits and surrogate endpoints of the therapies and on patients' management.