Failure Mechanisms and Neoatherosclerosis Patterns in Very Late Drug-Eluting and Bare-Metal Stent Thrombosis

Intravascular imaging in the diagnosis and management of patients with suspected intracoronary pathologies: A CJC White Paper

Intravascular imaging has become an integral part of the diagnostic and management strategies for intracoronary pathologies. This White Paper summarizes current evidence and its implications on the use of intravascular imaging in interventional cardiology practice. The areas addressed are planning and optimization of percutaneous coronary intervention, management of stent failure, and evaluation of ambiguous coronary lesions and myocardial infarction with non-obstructive coronary disease (MINOCA). Findings are presented following the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system in an expert consensus process involving a diverse Writing group and vetted by a Review group. Expert consensus was achieved around nine statements. Use of intravascular imaging in guiding percutaneous revascularization is supported by high quality evidence, particularly for lesions with increased risk of recurrent events or stent failure. Specific considerations for intravascular imaging guidance of intervention in left main lesions, chronic occlusion lesions as well as patients at high risk of contrast nephropathy are explored. Use of intravascular imaging to identify pathologies associated with stent failure and guide repeat intervention, resolve ambiguities in lesion assessment and establish diagnoses in patients presenting with MINOCA is supported by moderate to low quality evidence. Each topic is accompanied by clinical pointers to aid the practicing interventional cardiologist in implementation of the White paper findings. The findings of this White Paper will help to guide the utilization of intravascular imaging towards those situations in which the balance of efficacy, safety and cost are most optimal.

Impact of baseline yellow plaque assessed by coronary angioscopy on vascular response after stent implantation

BACKGROUND

The relationship between baseline yellow plaque (YP) and vascular response after stent implantation has not been fully investigated.

METHODS

This was a sub-analysis of the Collaboration-1 study (multicenter, retrospective, observational study). A total of 88 lesions from 80 patients with chronic coronary syndrome who underwent percutaneous coronary intervention were analyzed. Optical coherence tomography (OCT) and coronary angioscopy (CAS) were serially performed immediately and 11 months after stent implantation. YP was defined as the stented segment with yellow or intensive yellow color assessed by CAS. Neoatherosclerosis was defined as a lipid or calcified neointima assessed by OCT. OCT and CAS findings at 11 months were compared between lesions with baseline YP (YP group) and lesions without baseline YP (Non-YP group).

RESULTS

Baseline YP was detected in 37 lesions (42 %). OCT findings at 11 months showed that the incidence of neoatherosclerosis was significantly higher in the YP group (11 % versus 0 %, p = 0.028) and mean neointimal thickness tended to be lower (104 ± 43 μm versus 120 ± 48 μm, p = 0.098). CAS findings at 11 months demonstrated that the dominant and minimum neointimal coverage grades were significantly lower (p = 0.049 and P = 0.026) and maximum yellow color grade was significantly higher (p < 0.001) in the YP group.

CONCLUSIONS

Baseline YP affected the incidence of neoatherosclerosis as well as poor neointimal coverage at 11 months after stent implantation.

Mechanisms of Very Late Stent Thrombosis in Japanese Patients as Assessed by Optical Coherence Tomography

BACKGROUND

Although very late stent thrombosis (VLST) remains an important concern, the underlying etiology and clinical characteristics are not fully elucidated in Japanese patients who undergo intravascular imaging-guided percutaneous coronary intervention (PCI) regularly.

METHODS

We identified 50 VLST lesions (bare-metal stent [BMS] [n = 16], first-generation drug-eluting stent [DES] [n = 14] and newer-generation DES [n = 20]) in patients managed in our institutes. The underlying mechanism of VLST was assessed by optical coherence tomography (OCT), and the major etiology of each lesion was determined. The aim of this study was to explore the mechanisms of VLST of BMSs and DESs in Japanese patients.

RESULTS

The median duration since stent implantation was 10 years (range: 1-20). The most frequent etiology of VLST was neoatherosclerotic rupture (44%), followed by neointimal erosion (24%). Edge disease (10%) and evagination (10%) were similarly observed. Malapposition (8%) was deemed to be acquired late by looking at intravascular imaging from the index procedure. Uncovered struts (2%) and in-stent calcified nodule (2%) were the least frequent etiologies. Regardless of etiology, signs of neoatherosclerosis were present in most lesions (82%). Most patients received single (68%) or dual (8%) antiplatelet therapy or oral anticoagulation alone (4%), whereas a considerable proportion of patients discontinued medication (20%). Regarding the treatment strategy, drug-coated balloon was the most frequent strategy (56%), followed by implantation of newer DESs (34%).

CONCLUSIONS

Various mechanisms have been identified in Japanese patients with VLST. In these patients, biological responses seemed to be more relevant than the index procedure-related factors.

Two-year real world clinical outcomes after intravascular imaging device guided percutaneous coronary intervention with ultrathin-strut biodegradable-polymer sirolimus-eluting stent

BACKGROUND

There are little clinical data on imaging-guided percutaneous coronary intervention (PCI) 1 year after the biodegradable-polymer sirolimus-eluting stents (BP-SES) implantation, when the polymer disappears.

METHODS

We retrospectively analyzed 2455 patients who underwent successful PCI with BP-SES or durable-polymer everolimus-eluting stents (DP-EES) between September 2011 and March 2021, and compared 2-year clinical outcomes of BP-SES (n = 459) with DP-EES (n = 1996). The outcome measures were target lesion revascularization (TLR) and major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, target vessel revascularization, and stent thrombosis. Multivariate analysis using the Cox proportional hazard model and inverse probability weighting (IPW) analysis based on the propensity score were used to evaluate the clinical outcomes.

RESULTS

The 2-year cumulative incidences of TLR (BP-SES: 4.9% vs. DP-SES: 6.1%, p = 0.304) and MACE (10.3% vs. 12.5%, p = 0.159) were similar between the two groups. Multivariable and IPW analysis revealed the risks of TLR (p = 0.388 and p = 0.500) and MACE (p = 0.139 and p = 0.083) also had no significant difference. There was a significant interaction between none/mild and moderate/severe calcification with respect to MACE and TLR (adjusted p for interaction = 0.036 and 0.047, respectively). The risk of MACE was significantly lower in BP-SES than in DP-EES in lesions with none/mild calcification (adjusted hazard ratio [aHR]: 0.53; 95% confidence interval [CI]: 0.30-0.91), while it was similar in those with moderate/severe calcification (aHR: 0.95; 95% CI: 0.58-1.55).

CONCLUSIONS

Compared with DP-EES, BP-SES demonstrated durable 2-year clinical outcomes. However, BP-SES showed better clinical performance than DP-EES for lesions with none/mild calcification.

Very Late Stent Thrombosis Due to Neoatherosclerosis After Implantation of an Ultra-Thin Strut Stent

A 69-year-old man developed very late stent thrombosis (VLST) 3 years after Orsiro stent implantation in the proximal left anterior descending coronary artery. Intravascular imaging evaluations before and after the onset of VLST allowed us to document neoatherosclerosis as the etiology of VLST.

The relation of polymer structure of stent used in patients with acute coronary syndrome revascularized by stent implantation with long-term cardiovascular events

INTRODUCTION

Drug-eluting stents (DES) have revolutionized percutaneous coronary intervention (PCI) by improving event-free survival compared to older stent designs. However, early-generation DES with polymer matrixes have raised concerns regarding late stent thrombosis due to delayed vascular healing. To address these issues, biologically bioabsorbable polymer drug-eluting stents (BP-DES) and polymer-free drug-eluting stents (PF-DES) have been developed.

AIM

The aim of the present study is to evaluate and compare the long-term effects of different stent platforms in patients with acute coronary syndrome (ACS) undergoing PCI.

MATERIAL AND METHODS

We conducted a retrospective, observational study involving 1192 ACS patients who underwent urgent PCI. Patients were treated with thin- strut DP-DES, ultra-thin strut BP-DES, or thin-strut PF-DES. The primary endpoint was a composite of cardiac death, target vessel myocardial infarction (TVMI), and clinically driven target lesion revascularization (CITLR) at 12 months and 4 years.

RESULTS

The baseline demographics and clinical characteristics of patients in the three stent subgroups were similar. No significant differences were observed in target lesion failure (TLF), cardiac mortality, TVMI, and stent thrombosis (ST) rates among the three subgroups at both 12 months and 4 years. However, beyond the first year, the rate of CITLR was significantly lower in the ultra-thin strut BP-DES subgroup compared to thin-strut DP-DES, suggesting potential long-term advantages of ultra-thin strut BP-DES. Additionally, both ultra-thin strut BP-DES and thin-strut PF-DES demonstrated lower ST rates after the first year compared to thin-strut DP-DES.

CONCLUSION

Our study highlights the potential advantages of ultra-thin strut BP-DES in reducing CITLR rates in the long term, and both ultra-thin strut BP-DES and thin-strut PF-DES demonstrate lower rates of ST beyond the first year compared to thin-strut DP-DES. However, no significant differences were observed in overall TLF, cardiac mortality and TVMI rates among the three stent subgroups at both 12 months and 4 years.

The effect of sex differences on neointimal characteristics of in-stent restenosis in drug-eluting stents: An optical coherence tomography study

Background

Previous studies have demonstrated that there are sex-related differences in atherosclerosis. However, in terms of the nature of in-stent restenosis (ISR) neointima, the effect of gender on the results is unclear.

Methods

Patients with ISR of drug-eluting stents (DES) who underwent OCT examination in Senior Department of Cardiology of the Chinese People's Liberation Army General Hospital from March 2010 to March 2022 were included. The patients were divided into male and female groups.

Results

In this study, a total of 230 DES-ISR patients and 249 DES-ISR target lesions were analyzed. OCT data showed that compared to females, males have a higher incidence of thin-cap fibrous atherosclerosis (TCFA) (37.4% [n = 77] vs. 9.3% [n = 4], p < 0.001) and in-stent neoatherosclerosis (ISNA) (82.0% [n = 169] vs. 62.8% [n = 27]). p = 0.005). In addition, a multivariate logistic regression analysis demonstrated that male was independently associated with a higher incidence of ISNA (OR: 2.659, 95% CI: 1.239-5.707; p = 0.012) and TCFA (OR: 4.216, 95% CI: 1.370-12.976; p = 0.012).

Conclusion

For DES-ISR patients, the incidence of ISNA in female was significantly lower than that in male and vulnerability of neointimal pattern is lower in female than in male.

Clinical Impact of Drug-Coated Balloon-Based Percutaneous Coronary Intervention in Patients With Multivessel Coronary Artery Disease

BACKGROUND

Data on drug-coated balloon (DCB) treatment in the context of multivessel coronary artery disease (CAD) are limited.

OBJECTIVES

The purpose of this study was to investigate the impact of DCB-based treatment on percutaneous coronary intervention for multivessel CAD.

METHODS

A total of 254 patients with multivessel disease successfully treated with DCBs or in combination with drug-eluting stents (DES) were retrospectively enrolled (DCB-based group) and compared with 254 propensity-matched patients treated with second-generation DES from the PTRG-DES (Platelet Function and Genotype-Related Long-Term Prognosis in Drug-Eluting Stent-Treated Patients With Coronary Artery Disease) registry (n = 13,160) (DES-only group). Major adverse cardiovascular events (MACE) comprised cardiac death, myocardial infarction, stroke, stent thrombosis, target vessel revascularization, and major bleeding at 2 years.

RESULTS

Baseline clinical characteristics were comparable between the groups. In the DCB-based group, 34.3% of patients were treated with DCBs only and 65.7% were treated with the DES hybrid approach. The number of stents and total stent length were significantly reduced by 65.4% and 63.7%, respectively, in the DCB-based group compared with the DES-only group. Moreover, the DCB-based group had a lower rate of MACE than the DES-only group (3.9% and 11.0%; P = 0.002) at 2-year follow-up. The DES-only group had a higher risk for cardiac death and major bleeding.

CONCLUSIONS

The DCB-based treatment approach showed a significantly reduced stent burden for multivessel percutaneous coronary intervention and led to a lower rate of MACE than the DES-only treatment. This study shows that DCB-based treatment approach safely reduces stent burden in multivessel CAD, and improved long-term outcomes may be expected by reducing stent-related events. (Impact of Drug-Coated Balloon Treatment in De Novo Coronary Lesion; NCT04619277).

Identification of post-procedural optical coherence tomography findings associated with the 1-year vascular response evaluated by coronary angioscopy

Optical coherence tomography (OCT) provides higher resolution intravascular imaging and allows detailed evaluations of stent implantation sites post-percutaneous coronary intervention (PCI). Coronary angioscopy (CAS) can evaluate the vascular response after drug-eluting stent (DES) implantation. The post-PCI OCT findings that are associated with the CAS 1-year vascular response have not been known. We enrolled 168 lesions from 119 patients who underwent OCT-guided PCI using DES and follow-up CAS observation at 1 ± 0.5 year from August 2012 to December 2019. Outcome measures were sufficient neointimal coverage (NIC) defined as stent struts embedded in the neointima, subclinical intrastent thrombus, and vulnerable stented segments defined as those with angioscopic yellow or intensive yellow color 1 year after PCI. We identified the post-PCI OCT findings associated with these CAS findings. Sufficient NIC, subclinical intrastent thrombus, and vulnerable stented segment were detected in 85 lesions (51%), 47 lesions (28%), and 54 lesions (32%), respectively. A multivariate analysis demonstrated that malapposed struts were negatively associated with sufficient NIC (odds ratio 0.87; 95% CI 0.76-0.99; p = 0.029). However, no specific OCT findings immediately after PCI were associated with subclinical intrastent thrombus or vulnerable stented segment. Malapposition immediately after PCI was negatively associated with sufficient NIC at 1 year even without associations between post-PCI OCT findings and subclinical intrastent thrombus or vulnerable stented segment.

Pro-Healing Nanomatrix-Coated Stent Analysis in an In Vitro Vascular Double-Layer System and in a Rabbit Model

Cardiovascular stent technologies have significantly improved over time. However, their optimal performance remains limited by restenosis, thrombosis, inflammation, and delayed re-endothelialization. Current stent designs primarily target inhibition of neointimal proliferation but do not promote functional arterial healing (pro-healing) in order to restore normal vascular reactivity. The endothelial lining that does develop with current stents appears to have loose intracellular junctions. We have developed a pro-healing nanomatrix coating for stents that enhances healing while limiting neointimal proliferation. This builds on our prior work evaluating the effects of the pro-healing nanomatrix coating on cultures of vascular endothelial cells (ECs), smooth muscle cells (SMCs), monocytes, and platelets. However, when a stent is deployed in an artery, multiple vascular cell types interact, and their interactions affect stent performance. Thus, in our current study, an in vitro vascular double-layer (VDL) system was used to observe stent effects on communication between different vascular cell types. Additionally, we assessed the pro-healing ability and vascular cell interactions after stent deployment in the VDL system and in a rabbit model, evaluating the nanomatrix-coated stent compared to a commercial bare metal stent (BMS) and a drug eluting stent (DES). In vitro results indicated that, in a layered vascular structure, the pro-healing nanomatrix-coated stent could (1) improve endothelialization and endothelial functions, (2) regulate SMC phenotype to reduce SMC proliferation and migration, (3) suppress inflammation through a multifactorial manner, and (4) reduce foam cell formation, extracellular matrix remodeling, and calcification. Consistent with this, in vivo results demonstrated that, compared with commercial BMS and DES, this pro-healing nanomatrix-coated stent enhanced re-endothelialization with negligible restenosis, inflammation, or thrombosis. Thus, these findings indicate the unique pro-healing features of this nanomatrix stent coating with superior efficacy over commercial BMS and DES.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Prevalence and Impact of Neoatherosclerosis on Clinical Outcomes After Percutaneous Treatment of Second-Generation Drug-Eluting Stent Restenosis

BACKGROUND

Clinical and morphological factors associated with lipidic versus calcified neoatherosclerosis within second-generation drug-eluting stents and the impact of lipidic versus calcified neoatherosclerosis on long-term outcomes after repeat intervention have not been well studied.

METHODS

A total of 512 patients undergoing optical coherence tomography before percutaneous coronary intervention for second-generation drug-eluting stents in-stent restenosis were included. Neoatherosclerosis was defined as lipidic or calcified neointimal hyperplasia in ≥3 consecutive frames or ruptured lipidic neointimal hyperplasia. The primary outcome was target lesion failure (cardiac death, target vessel myocardial infarction, definite stent thrombosis, or clinically driven target lesion revascularization).

RESULTS

The overall prevalence of neoatherosclerosis was 28.5% (146/512): 56.8% lipidic, 30.8% calcified, and 12.3% both lipidic and calcific. The prevalence increased as a function of time from stent implantation: 20% at 1 to 3 years, 30% at 3 to 7 years, and 75% >7 years. Renal insufficiency, poor lipid profile, and time from stent implantation were associated with lipidic neoatherosclerosis, whereas severe renal insufficiency, female sex, and time from stent implantation were associated with calcified neoatherosclerosis. Multivariable Cox regression revealed that female sex and lipidic neoatherosclerosis were associated with more target lesion failure, whereas stent age and final minimum lumen diameter after reintervention were related to lower target lesion failure. Calcified neoatherosclerosis was not related to adverse events after reintervention for in-stent restenosis given a large enough minimum lumen diameter was achieved.

CONCLUSIONS

Lipidic but not calcified neoatherosclerosis was associated with poor subsequent outcomes after repeat revascularization if optimal stent expansion was achieved in lesions with calcified neoatherosclerosis.

In Stent Neo-Atherosclerosis: Pathophysiology, Clinical Implications, Prevention, and Therapeutic Approaches

Despite the dramatic improvements of revascularization therapies occurring in the past decades, a relevant percentage of patients treated with percutaneous coronary intervention (PCI) still develops stent failure due to neo-atherosclerosis (NA). This histopathological phenomenon following stent implantation represents the substrate for late in-stent restenosis (ISR) and late stent thrombosis (ST), with a significant impact on patient’s long-term clinical outcomes. This appears even more remarkable in the setting of drug-eluting stent implantation, where the substantial delay in vascular healing because of the released anti-proliferative agents might increase the occurrence of this complication. Since the underlying pathophysiological mechanisms of NA diverge from native atherosclerosis and early ISR, intra-coronary imaging techniques are crucial for its early detection, providing a proper in vivo assessment of both neo-intimal plaque composition and peri-strut structures. Furthermore, different strategies for NA prevention and treatment have been proposed, including tailored pharmacological therapies as well as specific invasive tools. Considering the increasing population undergoing PCI with drug-eluting stents (DES), this review aims to provide an updated overview of the most recent evidence regarding NA, discussing pathophysiology, contemporary intravascular imaging techniques, and well-established and experimental invasive and pharmacological treatment strategies.

Predictors and outcomes of neoatherosclerosis in patients with in-stent restenosis

BACKGROUND

In-stent restenosis (ISR), especially for neoatherosclerosis, is still a major problem of percutaneous coronary intervention (PCI) even in the drug-eluting stent (DES) era.

AIMS

The purpose of this study was to investigate the impact of neoatherosclerosis on prognosis after PCI for ISR.

METHODS

Between March 2009 and December 2017, 313 ISR lesions in patients undergoing an OCT-guided PCI in five hospitals were retrospectively enrolled. Neoatherosclerosis was defined as a lipid neointima or calcified neointima. We examined the association between neoatherosclerosis and the clinically driven target lesion revascularisation (CD-TLR) rates.

RESULTS

In 313 ISR lesions, 64 lesions (20.4%) had bare metal stents and 241 lesions (77.0%) had drug-eluting stents (DES). Among them, 47.0% of lesions (147 lesions) had neoatherosclerosis. A multivariate logistic regression analysis demonstrated that eGFR (odds ratio [OR] 0.986, 95% confidence interval [CI]: 0.974-0.998; p=0.023), the time from PCI to the ISR (OR 1.13, 95% CI: 1.06-1.22; p<0.001) and DES-ISR (OR 2.48, 95% CI: 1.18-5.43; p=0.019) were independent predictors for neoatherosclerosis. A multivariate regression analysis demonstrated that neoatherosclerosis was an independent predictor of CD-TLR.

CONCLUSIONS

In this multicentre ISR registry, OCT imaging demonstrated that eGFR, the time from PCI to the ISR and DES-ISR were independent predictors for neoatherosclerosis and that neoatherosclerosis in ISR lesions had a worse impact on the CD-TLR rate.

Impact of in-stent tissue characteristics on excimer laser coronary angioplasty prior to drug-coated balloon treatment

BACKGROUND

Percutaneous coronary intervention with drug-coated balloon (DCB) angioplasty is one of the standard treatments for lesions with in-stent restenosis (ISR). However, the efficacy of additional excimer laser coronary angioplasty (ELCA) for ISR lesions prior to DCB angioplasty has not been elucidated. The aims of this study were to elucidate the efficacy of ELCA prior to DCB treatment for ISR and the difference in effectiveness by lesion morphology.

METHODS

This was a multicenter, retrospective observational study. We enrolled 208 ISR lesions from 204 patients which were treated with DCB angioplasty under optical coherence tomography (OCT) guidance. We compared the acute gain evaluated by quantitative coronary angiography and clinically driven target lesion revascularization (CD-TLR) between the ELCA (+) (47 lesions) and ELCA (-) (161 lesions) groups.

RESULTS

The acute gain was significantly larger in the ELCA (+) group (1.51 ± 0.47 mm versus 1.29 ± 0.52 mm, P = 0.012). Even after adjustment for comorbidities, the ELCA had a significant impact on the acute gain (coefficient 0.24 [95% confidence interval 0.067-0.41]). In addition, the ELCA usage was significantly associated with larger acute gain in lesions with a homogeneous pattern, although there was no association between ELCA and either the heterogeneous pattern or neoatherosclerosis. The freedom from CD-TLR was not different between the ELCA (-) and ELCA (+) groups (hazard ratio 0.53 [0.24-1.18]).

CONCLUSIONS

ELCA had a significant impact on the larger acute gain in ISR lesions, especially may did in those with a homogenous pattern, while it did not impact CD-TLR significantly.

The effect of nanoparticles of cobalt-chromium on human aortic endothelial cells in vitro

Despite advances in stent technology for vascular interventions, in-stent restenosis (ISR) remains a main complication. The corrosion of cobalt-chromium (CoCr) alloy coronary stents has been identified to be associated with ISR, whereas its role in ISR has not been elucidated. In the current work, CoCr nanoparticles, simulated corrosion products of CoCr alloy, were used to investigate their effect on the endothelial cells. It has been demonstrated that the cell viability declines and the cell membrane is damaged, indicating the cytotoxicity of CoCr nanoparticles. The expression of GRP78, CHOP, and cleaved-caspase12 proteins has increased when exposed to CoCr nanoparticles, suggesting that CoCr nanoparticles induced cell apoptosis through endoplasmic reticulum (ER) stress-mediated apoptotic pathway. An increased release of adhesion and inflammatory mediators was also induced by CoCr nanoparticles, including ICAM-1, VCAM-1, IL-1β, IL-6, and TNF-α. Our results demonstrated that CoCr nanoparticles could trigger apoptosis, adhesion, and inflammation. These findings indicated potential damaging effects of CoCr nanoparticles on the vascular endothelium, which suggested corrosion of CoCr alloy may promote the progression and development of ISR.

Impact of diabetes mellitus on the early-phase arterial healing after drug-eluting stent implantation

BACKGROUND

Early arterial healing after drug-eluting stent (DES) implantation may enable short dual-antiplatelet therapy (DAPT) strategy. The impact of diabetes mellitus (DM) on this healing has not been elucidated. We used coronary angioscopy (CAS) to compare intravascular status of DM and non-DM patients in the early phase after DES implantation.

METHODS

This study was a multicenter retrospective observational study. We analyzed CAS findings of 337 lesions from 270 patients evaluated 3-5 months after DES implantation. We divided the lesion into two groups: DM (n = 149) and non-DM (n = 188). We assessed neointimal coverage (NIC) grades (dominant, maximum and minimum), thrombus adhesion and maximum yellow color grade. NIC was graded as follows: grade 0, stent struts were not covered; grade 1, stent struts were covered by thin layer; grade 2, stent struts were buried under neointima. Yellow color was graded as grade 0, white; grade 1, light yellow; grade 2, yellow; grade 3, intensive yellow.

RESULTS

Minimum NIC grade was significantly lower in DM than in non-DM groups (p = 0.002), whereas dominant and maximum NIC grades were similar between them (p = 0.59 and p = 0.94, respectively), as were thrombus adhesion (44.3% vs. 38.8%, p = 0.32) and maximum yellow color grade (p = 0.78). A multivariate analysis demonstrated that DM was an independent predictor of minimum NIC of grade 0 (odds ratio: 2.14, 95% confidence interval: 1.19-3.86, p = 0.011).

CONCLUSIONS

DM patients showed more uncovered struts than non-DM patients 3-5 months after DES implantation, suggesting that the recent ultra-short DAPT strategy might not be easily applied to DM patients.

Difference of vascular healing between bioabsorbable-polymer and durable-polymer new generation drug-eluting stents: an optical coherence tomographic analysis

The comparison of bioabsorbable-polymer and durable-polymer stents has continued to be debated, and there is ongoing concern regarding vascular healing and late stent thrombosis. This study compared the vascular healing at 8-month follow-up by optical coherence tomography (OCT) between 4 different kinds of new generation drug-eluting stents (DESs). We enrolled 112 patients (112 de novo lesions) who underwent OCT guided percutaneous coronary intervention with 4 kinds of new generation DESs including bioabsorbable-polymer everolimus-eluting stents (BP-EESs), bioabsorbable-polymer sirolimus-eluting stents (BP-SESs), durable-polymer everolimus-eluting stents (DP-EESs), and durable-polymer zotarolimus-eluting stents (DP-ZESs) and an 8-month follow-up angiogram and OCT were performed between July 2016 and April 2018. We divided them into two groups, namely BP and DP groups. We compared the OCT parameters including the percentage of uncovered struts, malapposed struts and the mean neointimal hyperplasia (NIH) thickness between the two groups. BP group consisted of 51 lesions (BP-EESs were used in 27, BP-SESs in 24 lesions) and DP group consisted of 61 lesions (DP-EESs were used in 35 and DP-ZESs in 26 lesions). The percentage of uncovered struts and malapposed struts were significantly lower (7.2 ± 8.9 vs. 15.0 ± 17.1%, p = 0.01, 0.9 ± 1.7 vs. 2.7 ± 5.2%, p = 0.03) and the mean NIH thickness was significantly thicker in BP group than DP group (112 ± 54 vs. 83 ± 31 µm, p < 0.01). The present OCT study demonstrated that uncovered struts and malapposed struts were less common with bioabsorbable-polymer stents than with durable-polymer stents.

Stent-Related Adverse Events >1 Year After Percutaneous Coronary Intervention

BACKGROUND

The majority of stent-related major adverse cardiovascular events (MACE) after percutaneous coronary intervention (PCI) are believed to occur within the first year. Very-late (>1-year) stent-related MACE have not been well described.

OBJECTIVES

The purpose of this study was to assess the frequency and predictors of very-late stent-related events or MACE by stent type.

METHODS

Individual patient data from 19 prospective, randomized metallic stent trials maintained at a leading academic research organization were pooled. Very-late MACE (a composite of cardiac death, myocardial infarction [MI], or ischemia-driven target lesion revascularization [ID-TLR]), and target lesion failure (cardiac death, target-vessel MI, or ID-TLR) were assessed within year 1 and between 1 and 5 years after PCI with bare-metal stents (BMS), first-generation drug-eluting stents (DES1) and second-generation drug-eluting stents (DES2). A network meta-analysis was performed to evaluate direct and indirect comparisons.

RESULTS

Among 25,032 total patients, 3,718, 7,934, and 13,380 were treated with BMS, DES1, and DES2, respectively. MACE rates within 1 year after PCI were progressively lower after treatment with BMS versus DES1 versus DES2 (17.9% vs. 8.2% vs. 5.1%, respectively, p < 0.0001). Between years 1 and 5, very-late MACE occurred in 9.4% of patients (including 2.9% cardiac death, 3.1% MI, and 5.1% ID-TLR). Very-late MACE occurred in 9.7%, 11.0%, and 8.3% of patients treated with BMS, DES1, and DES2, respectively (p < 0.0001), linearly increasing between 1 and 5 years. Similar findings were observed for target lesion failure in 19,578 patients from 12 trials. Findings were confirmed in the network meta-analysis.

CONCLUSIONS

In this large-scale, individual patient data pooled study, very-late stent-related events occurred between 1 and 5 years after PCI at a rate of ∼2%/year with all stent types, with no plateau evident. New approaches are required to improve long-term outcomes after PCI.

Stent Thrombosis After Percutaneous Coronary Intervention: From Bare-Metal to the Last Generation of Drug-Eluting Stents

Since their introduction in clinical practice in 1986, different types of coronary stents have been developed and become available for the treatment of coronary artery disease. Stent thrombosis (ST) is an uncommon but harmful complication after percutaneous coronary implantation, with a high occurrence of acute myocardial infarction and risk of mortality. Among several procedural and clinical predictors, the type of coronary stent is a strong determinant of ST. This article reviews the available evidence on the most used coronary stent types in the modern era and the related risk of ST.

Coronary Intravascular Brachytherapy for Recurrent Coronary Drug-Eluting Stent In-Stent Restenosis: A Systematic Review and Meta-Analysis

OBJECTIVE

To examine the outcomes with intravascular brachytherapy (IVBT) in recurrent in-stent restenosis (ISR).

BACKGROUND

Recurrent ISR can be challenging to treat and IVBT can be used for recurrent ISR but has received limited study.

METHODS

We performed a systematic review and meta-analysis of five observational studies, including 917 patients (1014 lesions) with recurrent ISR, defined as having at least two prior ISR episodes with previous treatment with a stent, who underwent treatment with IVBT. Outcomes of interest included target vessel revascularization (TVR), myocardial infarction (MI), and all-cause mortality.

RESULTS

During a mean follow-up of 24 ± 7 months, the incidence of TVR was 29.2% (95% CI 18.0-40.4%). The incidence of MI and all-cause mortality were 4.3% (95% CI 1.7%-6.9%) and 7.3% (95% CI 3.2-11.5%), respectively. At one- and two-years after PCI the incidence of TVR was 17.5% (95% CI 13.6%-21.4%) and 26.7% (95% CI 16.6%-36.9%), respectively and the incidence of MI was 3.1% (95% CI 2-4.2%) and 3.9% (95% CI 1-6.8%), respectively.

CONCLUSION

Intravascular brachytherapy can be used to treat recurrent ISR, although TVR is needed in approximately one of four patients at two years.

Comparison of drug-eluting stents vs. drug-coated balloon after rotational atherectomy for severely calcified lesions of nonsmall vessels

Calcified lesion is a risk factor for adverse events, even in the drug-eluting stent (DES) era. Recently, drug-coated balloon (DCB) has been shown to have favourable results for in-stent restenosis and small vessels, but its results for calcified lesions are unknown. This study aimed to clarify the rotational atherectomy (RA) and DCB results for calcified lesions of nonsmall vessels. A total of 194 consecutive de novo lesions from 165 cases underwent RA for calcified lesions of nonsmall vessels between January 2016 and August 2018 in a single centre. Overall, 8 cases/10 lesions were excluded because of RA followed plain old balloon angioplasty (POBA). Remaining lesions were grouped into the DES (88 cases/104 lesions) and DCB (69 cases/80 lesions) groups and then compared retrospectively. The primary endpoint was post-discharge major adverse cardiovascular events (MACE) at 1 year, and it was defined as cardiac death, noncardiac death, target-vessel-related myocardial infarction, target lesion revascularization (TLR), and major bleeding (BARC ≥ type 3). There was no difference in the clinical follow-up rate between RA + DES (96/104 lesions) and RA + DCB (78/80 lesions). The post-discharge MACE values after 1 year of RA + DES and RA + DCB were 8% and 11% (P = 0.30), respectively, in terms of cardiac death (0% vs. 0%, respectively), noncardiac death (4% vs. 3%, respectively, P = 0.36), target-vessel-related myocardial infarction (0% vs. 0%, respectively), TLR (4% vs. 8%, respectively, P = 0.30), and major bleeding (1% vs. 0%, respectively). For calcified lesions of nonsmall vessels, RA + DCB showed good results as well as RA + DES. RA + DCB is a potential new strategy for these lesions.

Long-Term Outcomes After Revascularization for Stable Ischemic Heart Disease

Background:

Whether revascularization improves prognosis in stable ischemic heart disease is controversial.

Methods:

Individual patient-level data from 19 prospective, randomized stent trials were pooled. Rates of 5-year major adverse cardiovascular events (MACE; a composite of cardiac death, myocardial infarction, or ischemia-driven target lesion revascularization) were assessed and compared after percutaneous coronary intervention with bare-metal stents (BMS) and first-generation and second-generation drug-eluting stents (DES1 and DES2, respectively). Poisson multivariable regression analysis was performed to identify predictors of adverse events.

Results:

Among 10 987 patients treated with percutaneous coronary intervention for stable ischemic heart disease, 1550, 2776, and 6661 received BMS, DES1, and DES2, respectively. The 5-year rates of MACE progressively declined with evolution in stent technology (BMS: 24.1% versus DES1: 17.9% versus DES2: 13.4%, P <0.0001). However, MACE rates between 1 and 5 years increased from BMS to DES1, then declined with DES2 (BMS: 7.4% versus DES1: 10.2%, DES2: 8.5%, P =0.02).

Conclusions:

Patients with stable ischemic heart disease remain at substantial risk for long-term MACE after revascularization with percutaneous coronary intervention, even with contemporary DES. New approaches to reduce the ongoing risk of MACE beyond 1 year after stent implantation are necessary.

Three-year clinical outcome of biodegradable hybrid polymer Orsiro sirolimus-eluting stent and the durable biocompatible polymer Resolute Integrity zotarolimus-eluting stent: A randomized controlled trial

AIMS

We compared long-term clinical outcomes between patients treated with Orsiro sirolimus-eluting stent (O-SES) and those treated with durable biocompatible polymer Resolute Integrity zotarolimus-eluting stent (R-ZES).

METHODS AND RESULTS

The ORIENT trial was a randomized controlled noninferiority trial to compare angiographic outcomes between O-SES and R-ZES. We performed a post hoc analysis of 3-year clinical outcomes and included 372 patients who were prospectively enrolled and randomly assigned to O-SES (n = 250) and R-ZES (n = 122) groups in a 2:1 ratio. The primary endpoint was target lesion failure defined as a composite of cardiac death, nonfatal myocardial infarction, and target lesion revascularization. At 3 years, target lesion failure occurred in 4.7% and 7.8% of O-SES and R-ZES groups, respectively (hazard ratio, 0.58; 95% confidence intervals, 0.24-1.41; p = .232 by log-rank test). Secondary endpoints including cardiac death, myocardial infarction, and target lesion revascularization showed no significant differences between the groups. Stent thrombosis occurred in two patients in R-ZES group (0.0% vs. 1.6%, p = .040).

CONCLUSION

This study confirms long-term safety and efficacy of the two stents. We found a trend for lower target lesion failure with O-SES compared to R-ZES, although statistically insignificant.

Optical coherence tomography evaluation of the absorb bioresorbable scaffold performance for overlap versus non-overlap segments in patients with coronary chronic total occlusion: insight from the GHOST-CTO registry

The Absorb bioresorbable vascular scaffold (BVS) promised to avoid some of the disadvantages of its metal predecessors. Even though it has been taken off the market, limited data is available about its use in coronary chronic total occlusion (CTO) and its performance in overlap segments, which would be of special research interest due to its large thickness. This data is still pertinent since the platform of bioresorbable devices has not been abandoned, with several companies working on it. We aimed to compare healing and performance between overlap (OL) and non-overlap regions (NOL) of CTO lesions treated with BVS, using optical coherence tomography (OCT). Fourteen patients with overlapping BVS were included from the GHOST-CTO registry, resulting in 25 OL and 38 NOL regions. OCT based parameters were compared between OL and NOL groups at baseline (post-implantation) and 12-month follow-up. The mean age was 61.7 ± 7.2 years and 12 (86%) were males. Twelve (86%) patients underwent PCI for stable coronary artery disease and 2 (14%) had unstable angina. At 12-month follow-up, mean lumen area decreased in both NOL and OL regions, but the decrease was significantly larger in the OL region (NOL - 0.7 ± 1.33 vs. OL - 2.4 ± 1.54 mm²; p = 0.002). Mean scaffold area increased in both regions, but increased significantly more in NOL ( + 1.1 ± 1.54 vs. + 0.4 ± 1.16 mm²; p = 0.016). The percent of uncovered struts was lower in the OL group (5.0 ± 6.6% vs. 3.75 ± 8.7%, p = 0.043), whereas the percentage of malapposed struts was similar (0.3 ± 0.5% vs. 0.7 ± 2.3%, p = 0.441). Neointimal hyperplasia (NIH) was more pronounced in the OL region (0.13 ± 0.04 vs. 0.24 ± 0.10 mm², p = 0.001). The OL and NOL segments showed comparable healing in terms of coverage and malapposition. However, NIH was more prominent in OL region. The long-term clinical implications of these findings needs further evaluation. The present study provides important insights for future development of BVS technology.

Vulnerable neoatherosclerosis in coronary artery with whole circumference showing intravascular echo attenuation

Neoatherosclerosis is emerging as a stent-associated problem that has not yet been fully resolved. Because in-stent restenosis with a neoatherosclerotic etiology is associated with a high risk of acute coronary syndrome and a poor survival prognosis, it is essential to precisely identify patients at risk using advanced imaging modalities.

Recurrent atherosclerosis complications as a mechanism for stent failure

Stents are an indispensable tool in the percutaneous treatment of symptomatic coronary artery disease. Yet, stent failure due to restenosis or thrombosis may compromise their clinical benefit, carrying substantial morbidity and mortality. Despite improvements in device design and adjunctive medical treatment, stent failure still occurs during long-term follow-up, suggesting that this may be an issue that persists for many years, perhaps indefinitely. Numerous studies during the last decade have highlighted the previously underappreciated pivotal role of atherosclerosis in stent failure. We review evolving evidence on the role of atherosclerosis in stent restenosis and thrombosis, differentiating between de novo in-stent atherosclerosis development (i.e., neoatherosclerosis) and progression of pre-existing underlying atherosclerosis (i.e., paleoatherosclerosis), a distinction with potentially important clinical implications. We conclude with a concept that provides a unifying pathophysiology for these significant problems in the field of interventional cardiology based on the progression and destabilization of atherosclerosis.

Neoatherosclerosis after drug-eluting stent implantation: a novel clinical and therapeutic challenge

The recognition that obstructive disease of the epicardial coronary arteries, causing ischaemic heart disease, can be treated with a percutaneous coronary intervention (PCI) has been a major discovery in cardiology in the last 40 years contributing, in particular, to the reduction of mortality associated to acute myocardial infarction (AMI). However, even in the era of drug-eluting stent (DES) implantation, a sizable proportion of patients who undergo PCI may develop late or very late post-implantation complications, that occur in the form of restenosis, neoatherosclerosis, and/or in-stent thrombosis. Such complications are clinically relevant since they can cause AMI and negatively impact on the outcome. The underlying pathophysiological mechanisms are complex but related to inhibition of neointimal proliferation by DES that, on the hand, reduces the rate of in-stent restenosis, but, on the other hand, causes dysfunctional vessel healing, persistent inflammation, platelet activation, and adverse immunological responses. Multiple approaches have been developed or are under evaluation to target DES-related complications including pharmacotherapy, procedure-related imaging methods, novel stent designs, and drug-delivery methods. The aim of this review is to provide an update on the latest preclinical, translational, and clinical pharmacotherapeutic developments in this setting that target novel cellular mechanisms and pathways that might contribute to neoatherosclerosis. Due to the importance of secondary prevention in the reduction of DES-associated complications, this review also provides a short overview of pharmacological agents that are established or currently being investigated in this regard.

Long-term safety of bioresorbable scaffolds: insights from a network meta-analysis including 91 trials

AIMS

The aim of this study was to investigate the long-term safety and efficacy of biodegradable scaffolds and metallic stents.

METHODS AND RESULTS

We analysed a total of 91 randomised controlled trials with a mean follow-up of 3.7 years in 105,842 patients which compared two or more coronary metallic stents or biodegradable scaffolds and reported the long-term clinical outcomes (≥2 years). Network meta-analysis showed that patients treated with the Absorb bioresorbable vascular scaffold (BVS) had a significantly higher risk of definite or probable scaffold thrombosis (ScT) compared to those treated with metallic DES. The risk of very late ScT was highest with the Absorb BVS among comparators. Pairwise conventional meta-analysis demonstrated that the elevated risk of ScT with Absorb BVS compared to cobalt-chromium everolimus-eluting stents was consistent across the time points of ≤30 days (early), 31 days - 1 year (late) and >1 year (very late) ScT. In addition, target lesion failure rates were significantly higher in the Absorb BVS cohort, driven by both increased risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularisation.

CONCLUSIONS

Absorb BVS implantation was associated with increased risk of long-term and very late ScT compared to current-generation metallic DES. The risk of ScT occurred with a rising trend beyond one year.

TGFβ, smooth muscle cells and coronary artery disease: a review

Excessive vascular smooth muscle cell (SMC) proliferation, migration and extracellular matrix (ECM) synthesis are key events in the development of intimal hyperplasia, a pathophysiological response to acute or chronic sources of vascular damage that can lead to occlusive narrowing of the vessel lumen. Atherosclerosis, the primary cause of coronary artery disease, is characterised by chronic vascular inflammation and dyslipidemia, while revascularisation surgeries such as coronary stenting and bypass grafting represent acute forms of vascular injury. Gene knockouts of transforming growth factor-beta (TGFβ), its receptors and downstream signalling proteins have demonstrated the importance of this pleiotropic cytokine during vasculogenesis and in the maintenance of vascular homeostasis. Dysregulated TGFβ signalling is a hallmark of many vascular diseases, and has been associated with the induction of pathological vascular cell phenotypes, fibrosis and ECM remodelling. Here we present an overview of TGFβ signalling in SMCs, highlighting the ways in which this multifaceted cytokine regulates SMC behaviour and phenotype in cardiovascular diseases driven by intimal hyperplasia.

Update on pathological platelet activation in coronary thrombosis

Although coronary thrombosis (CT) is integral to cardiovascular outcomes, the underlying pathophysiological mechanisms remain unclear. CT may occur in case of atherosclerotic plaque erosion/rupture, or even after stenting implantation. Platelets (PLT) activation is the keystone of atherothrombosis and depends on many dysregulated elements, including endothelial dysfunction, oxidized lipoproteins, and immune response. Besides the classical view of PLT as an effector of hemostatic response, a new repertoire of PLT activities is emerging. PLT lipidome oxidation is a self-maintaining process which promotes PLT reactivity, coagulation cascade, and inflammatory cell activation. PLT-innate immune cell interaction is also sustained by neutrophil extracellular traps and NLRP3 inflammasome pathways. Other noteworthy emerging mechanisms are implicated in the crosstalk between PLT and surrounding cells. Especially, microvesicles (MVs) released from PLT may extend their signaling network far beyond the classical cell-cell interactions. Moreover, the recognition of noncoding RNA in PLT MVs introduce another layer of complexity in terms of intercellular signaling by a direct regulation of messenger RNA profile and gene expression in the recipient cells. The aim of this narrative review is to update the recent advance in CT and intracoronary stent thrombosis, including causal factors and potential translation of experimental evidence into the clinical setting.

Different behaviors of bioresorbable vascular scaffold in different types of calcified lesion: Insights from intravascular imaging

A 55-year-old male underwent percutaneous coronary intervention (PCI) for left anterior descending artery chronic total occlusion. After lesion preparation with non-compliant (NC) balloon, two bioresorbable vascular scaffolds (2.5/28 mm, 3.0/28 mm, Absorb BVS, Abbott Vascular, Santa Clara, CA, USA) were implanted followed by 1:1 sized NC balloon post-dilatation at 20 atm. Final intravascular ultrasound (IVUS) showed acceptable BVS expansion in diffusely calcified lesions. Twenty-one months' follow-up coronary angiography revealed severe restenosis with reocclusion at the distal edge of the distal BVS. After recanalization with a 1.0 mm balloon, optical coherence tomography (OCT) was performed. Quantitative analysis comparing OCT and IVUS at the index procedure demonstrated that minimum scaffold area at follow-up became significantly smaller and with higher eccentricity, suggesting severe recoil at the lesions with thick calcium spot, whereas these changes were not observed at the lesion with relatively thin calcification. The lesions were successfully revascularized with drug-eluting stents and final OCT showed symmetric expansion of metallic stents. Our case demonstrates that different types of calcification can have an impact on BVS expansion and recoil. In calcified lesions, an optimal implantation technique is mandatory to achieve the best possible results, and characterization of calcified lesions with intravascular imaging may be helpful to decide PCI strategy with BVS. <Learning objective: Calcified lesions represent a challenging lesion subset for bioresorbable vascular scaffold (BVS) because of less radial strength of the latter. Quantitative analysis with intravascular imaging demonstrated that different types of calcification can have an impact on BVS expansion and recoil. In calcified lesions, an optimal implantation technique is mandatory to achieve the best possible results, and characterization of calcified lesions with intravascular imaging may be helpful to decide percutaneous coronary intervention strategy with BVS.>.

A serial 3- and 9-year optical coherence tomography assessment of vascular healing response to sirolimus- and paclitaxel-eluting stents

Early-generation drug-eluting stents (DES) have been demonstrated to delay vascular healing. Limited optical coherence tomography (OCT) data on the very long-term neointimal response after DES implantation are available. The aim of this study was a serial OCT assessment of neointimal thickness, stent strut coverage, malapposition, and protrusion as markers of neointimal response at 3 and 9 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES). In this single-centre, longitudinal study consecutive patients undergoing elective PCI with SES or PES were included. OCT analysis was performed after 3 and 9 years by the independent core laboratory. A total of 22 subjects (8 SES and 14 PES) underwent an OCT assessment at 3 and 9 years post index procedure. The lumen, neointimal and malapposition area and the neointimal thickness (SES ∆50 µm, p = 0.195, PES ∆10 µm, p = 0.951) did not change significantly over the 6 year follow-up. No differences in the incidence of uncovered, malapposed or protruding struts were found in each type of stent. At 3 and 9 years after PCI, implantation of early-generation SES and PES may be associated with similar neointimal thickness, strut coverage, malapposition and protrusion, as assessed by serial OCT examination among patients with uneventful follow-up at 3 years post procedure. The small size of the study warrants judicious interpretation of our results and confirmation in larger multimodality imaging studies, including patients treated with contemporary stent platforms.

Are acute coronary syndromes an ideal scenario for bioresorbable vascular scaffold implantation?

Bioresorbable vascular scaffolds (BRS) represent the latest innovation in the field of interventional cardiology. BRS have recently been introduced in routine clinical practice and their use has progressively extended in everyday clinical practice. The BRS use appears theoretically attractive in patients presenting with acute coronary syndromes (ACS) as they are generally young with long life expectancy, thus possibly benefiting more of the so-called vascular reparative therapy. Furthermore, "culprit" lesions are usually softer and more easily expandable by current BRS compared to stable chronic lesions. However an increased risk of BRS thrombosis has been reported in clinical trials excluding ACS patients. Therefore, concerns have been raised on the safety of BRS implantation in the ACS setting in which the risk of thrombotic recurrences is definitely higher (compared to stable lesions) independently by the device implanted. Aim of this review is to provide an overview of the available data on the BRS performance in ACS patients.

Thirty-Day Outcomes After Unrestricted Implantation of Bioresorbable Vascular Scaffold (from the Prospective RAI Registry)

The Absorb biovascular scaffold (BVS) is a bioresorbable, everolimus-eluting scaffold whose data on real-world patients with complex lesions are limited. Short-term follow-up from recent studies point to a higher rate of 30-day thrombosis than observed with drug-eluting stents. We aimed to understand the short-term safety and efficacy of BVS. Registro Absorb Italiano (RAI, ClinicalTrials.gov:NCT02298413) is an Italian, prospective, multicenter registry not funded, whose aim is to investigate BVS performance through a 5-year follow-up of all consecutive patients who have undergone successful implantation of ≥1 BVS in different clinical/lesion subsets. Co-primary end points were target lesion revascularization and definite/probable thrombosis. Secondary end point was the occurrence of device-oriented cardiac events. The registry involved 23 centers, with patient enrollment from October 2012 to December 2015. We here report the 30-day outcomes of the whole population of the registry. We enrolled 1,505 consecutive patients, of which 82% were men and 22.4% diabetic. At presentation, 59.6% of the patients had an acute coronary syndrome, including 21% ST-elevation myocardial infarction. All lesions were pre-dilated and in 96.8% of the cases BVS was post-dilated. At 30 days, the co-primary study end point target lesion revascularization occurred in 0.6% of patients and definite/probable BVS thrombosis in 0.8%. There were 2 cases of cardiac and overall death (0.13%). Device-oriented cardiac events occurred in 1% of the patients. In conclusion, our data of consecutive patients suggest that current use of BVS in a wide spectrum of coronary narrowings and clinical settings is associated with good outcome at 30 days.

Characteristics of Earlier Versus Delayed Presentation of Very Late Drug-Eluting Stent Thrombosis: An Optical Coherence Tomographic Study

Background

The pathophysiology underlying very late drug‐eluting stent (DES) thrombosis is not sufficiently understood. Using optical coherence tomography, we investigated characteristics of very late stent thrombosis (VLST) according to different onset times.

Methods and Results

A total of 98 patients from 10 South Korean hospitals who underwent optical coherence tomography for evaluation of very late DES thrombosis were retrospectively included in analyses. VLST occurred at a median of 55.1 months after DES implantation. All patients were divided into 2 equal groups of earlier versus delayed presentation of VLST, according to median onset time. In total, 27 patients were treated with next‐generation DES and 71 with first‐generation DES. Based on optical coherence tomography findings at thrombotic sites, main VLST mechanisms were as follows, in descending order: neoatherosclerosis (34.7%), stent malapposition (33.7%), and uncovered struts without stent malapposition or evagination (24.5%). Compared with patients with earlier VLST, patients with delayed VLST had lower frequency of uncovered struts without stent malapposition or evagination (34.7% versus 14.3%, respectively; P=0.019). Conversely, the frequency of neoatherosclerosis was higher in patients with delayed versus earlier VLST (44.9% versus 24.5%, respectively; P=0.034). The frequency of stent malapposition was not different between patients with earlier and delayed VLST (34.7% versus 32.7%, respectively; P=0.831). The frequency of stent malapposition, evagination, and uncovered struts was still half of delayed VLST.

Conclusions

The pathological mechanisms of very late DES thrombosis changed over time. Delayed neointimal healing remained a substantial substrate for VLST, even long after DES implantation.