Long-term outcomes of neointimal hyperplasia without neoatherosclerosis after drug-eluting stent implantation

Deep learning model DeepNeo predicts neointimal tissue characterization using optical coherence tomography

BACKGROUND

Accurate interpretation of optical coherence tomography (OCT) pullbacks is critical for assessing vascular healing after percutaneous coronary intervention (PCI). Manual analysis is time-consuming and subjective, highlighting the need for a fully automated solution.

METHODS

In this study, 1148 frames from 92 OCT pullbacks were manually annotated to classify neointima as homogeneous, heterogeneous, neoatherosclerosis, or not analyzable on a quadrant level. Stent and lumen contours were annotated in 305 frames for segmentation of the lumen, stent struts, and neointima. We used these annotations to train a deep learning algorithm called DeepNeo. Performance was further evaluated in an animal model (male New Zealand White Rabbits) of neoatherosclerosis using co-registered histopathology images as the gold standard.

RESULTS

DeepNeo demonstrates a strong classification performance for neointimal tissue, achieving an overall accuracy of 75%, which is comparable to manual classification accuracy by two clinical experts (75% and 71%). In the animal model of neoatherosclerosis, DeepNeo achieves an accuracy of 87% when compared with histopathological findings. For segmentation tasks in human pullbacks, the algorithm shows strong performance with mean Dice overlap scores of 0.99 for the lumen, 0.66 for stent struts, and 0.86 for neointima.

CONCLUSIONS

To the best of our knowledge, DeepNeo is the first deep learning algorithm enabling fully automated segmentation and classification of neointimal tissue with performance comparable to human experts. It could standardize vascular healing assessments after PCI, support therapeutic decisions, and improve risk detection for cardiac events.

Prognostic implications of quantitative flow ratio and optical coherence tomography-guided neointimal characteristics in drug-coated balloon treatment for in-stent restenosis

The aim of this study was to investigate the relationship between quantitative flow ratio (QFR) after drug-coated balloon (DCB) treatment for in-stent restenosis (ISR) and between neointimal characteristics assessed by optical coherence tomography (OCT) and clinical outcomes. This single-center, retrospective, observational cohort study included ISR patients who underwent DCB angioplasty under OCT guidance. The primary outcome of the study was a target vessel failure (TVF), defined as a composite endpoint of cardiovascular death, target vessel myocardial infarction and target vessel revascularization. During a median follow-up of 756 days (IQR: 443.25, 1134.50), 204 ISR patients underwent OCT-guided DCB angioplasty, resulting in TVF development in 27 patients. At the post-procedural DCB angioplasty, the vessel-level QFR was significantly lower in the TVF group (0.89 [IQR: 0.87, 0.93] vs. 0.93 [IQR: 0.91, 0.96]; P < 0.001) than in the non-TVF group. Analysis of the qualitative characteristics of ISR lesions showed a significantly higher incidence of heterogeneous neointima in the TVF group compared with the non-TVF group (13 [48.15%] vs. 32 [18.08%]; P < 0.001). In the multivariable Cox regression analysis, low vessel-level QFR (HR per 0.1 increase: 0.11; 95% CI: 0.03-0.41; P < 0.001) and heterogeneous neointima were independently associated with TVF. The TVF rate of vessels with the 2 features was 10.69 times higher than that of all other vessels (95%CI [2.05-55.79]; log-rank P < 0.0001). Vessel-level QFR and heterogeneous neointima were independent factors associated with TVF in ISR patients after DCB angioplasty. Adding the QFR measure-ment to OCT findings may enable better discrimination of patients with subsequent TVF post-DCB angioplasty for ISR.

Optical Coherence Tomography Findings in Patients Presenting With In-Stent Restenosis: A Prospective Observational Study of Patterns of Neointimal Hyperplasia and Associated Risk Factors

Introduction Morphological features of neointimal tissue play a pivotal role in the pathophysiology of in-stent restenosis (ISR) after percutaneous coronary intervention (PCI). This study was designed to qualitatively and quantitatively assess neointimal characteristics of lesions using optical coherence tomography (OCT) in patients presenting with ISR.  Methods This was a single-center, prospective, observational study performed at a tertiary-care center in India. Patients diagnosed with stable angina and acute coronary syndrome with post-procedural angiographically documented restenosis (>50%) were included. Results A total of 34 patients with ISR were studied. Neointimal hyperplasia was classified as (i) homogenous group (n = 18) and (ii) non-homogenous group (n = 16). Fourteen (77.8%) diabetics belonged to the homogenous group. Predominant plaque characteristics such as neoatherosclerosis, cholesterol crystals, and calcium were documented in 14 (77.8%), 12 (66.7%), and 11 (61.1%) patients in the homogenous group and 10 (62.5%), 10 (62.5%), and 9 (56.2%) patients in the non-homogenous group, respectively. Unexpanded stent struts were identified in 11 (61.1%) and 11 (68.8%) patients in the homogenous and non-homogenous groups, respectively. Mean strut thickness was 93.73 ± 31.03 µm and 83.54 ± 18.0 µm, ISR was 72.50 ± 15.93% and 65.37 ± 21.69%, the neointimal thickness was 588.06 ± 167.82 μm and 666.25 ± 218.05 μm, and neointimal hyperplasia was 54.54 ± 11.23% and 59.26 ± 8.86% in the homogenous and non-homogenous groups, respectively. Conclusion Neoatherosclerosis and stent underexpansion were predominantly observed in our study and only diabetes was found to be significantly associated with homogenous neointimal hyperplasia.

Intravascular Imaging for Guiding In-Stent Restenosis and Stent Thrombosis Therapy

Advances in stent technology and the design of endovascular devices with thinner struts, anti-inflammatory and antithrombotic polymers, and better drug kinetics have enhanced the safety and efficacy of the second-generation drug-eluting stents and broadened their use in the therapy of high-risk patients and complex anatomies. However, despite these developments, in-stent restenosis and stent thrombosis remain the Achilles' heel of percutaneous coronary intervention, with their cumulative incidence reaching up to 10% at 5 years following percutaneous coronary intervention. The treatment of stent failure poses challenges and is associated with a worse prognosis than conventional percutaneous coronary intervention. Several studies have recently highlighted the value of intravascular imaging in identifying causes of stent failure, underscored its role in treatment planning, and registries have shown that its use may be associated with better clinical outcomes. The present review aims to summarize the evidence in the field; it discusses the value of intravascular imaging in identifying the mechanisms of in-stent restenosis and stent thrombosis in assessing the morphological characteristics of neointima tissue that appears to determine long-term outcomes in evaluating procedural results, and presents the findings of studies supporting its value in guiding therapy in stent failure.

Intracoronary Imaging of Vulnerable Plaque-From Clinical Research to Everyday Practice

The introduction into clinical practice of intravascular imaging, including intravascular ultrasound (IVUS), optical coherence tomography (OCT) and their derivatives, allowed for the in vivo assessment of coronary atherosclerosis in humans, including insights into plaque evolution and progression process. Intravascular ultrasound, the most commonly used intravascular modality in many countries, due to its low resolution cannot assess many features of vulnerable plaque such as lipid plaque or thin-cap fibroatheroma. Thus, novel methods were introduced to facilitate this problem including virtual histology intravascular ultrasound and later on near-infrared spectroscopy and OCT. Howbeit, none of the currently used modalities can assess all known characteristics of plaque vulnerability; hence, the idea of combining different intravascular imaging methods has emerged including NIRS-IVUS or OCT-IVUS imaging. All of those described methods may allow us to identify the most vulnerable plaques, which are prone to cause acute coronary syndrome, and thus they may allow us to introduce proper treatment before plaque destabilization.

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.

Effect of Rivaroxaban and Clopidogrel Combination Therapy on In-Stent Responses After Everolimus-Eluting Stent Implantation in a Porcine Coronary Model

AIM

According to recent clinical trials, a combination of direct oral anticoagulants with antiplatelet drugs is often recommended for atrial fibrillation patients who receive drug-eluting stents (DESs). Although the optimal combination comprises direct factor Xa inhibitors and a P2Y12 receptor antagonist (or aspirin), their influence on vascular responses to DESs remains unclear.

METHODS

Pigs were given either aspirin and clopidogrel (dual antiplatelet therapy [DAPT] group), aspirin and rivaroxaban (AR group), or clopidogrel and rivaroxaban (CR group), followed by everolimus-eluting stent (Promus Element) implantation into the coronary artery. Stented coronary arteries were evaluated via intravascular optical coherence tomography (OCT) and histological analysis at 1 and 3 months.

RESULTS

OCT revealed lower neointimal thickness in the DAPT group and comparable thickness among all groups at 1 and 3 months, respectively. Histological analyses revealed comparable neointimal area among all groups and the smallest neointimal area in the CR group at 1 and 3 months, respectively. In the DAPT and AR groups, the neointima continued to grow from 1 to 3 months. A shortened time course for neointima growth was observed in the CR group, with rapid growth within a month (maintained for 3 months). A higher incidence of in-stent thrombi was observed in the AR group at 1 month; no thrombi were found in either group at 3 months. More smooth muscle cells with contractile features were found in the CR group at both 1 and 3 months.

CONCLUSIONS

Our results proved the noninferiority of the combination of rivaroxaban with an antiplatelet drug, particularly the dual therapy using rivaroxaban and clopidogrel, compared to DAPT after DES implantation.

Hangover after Side Branch Stenting: The Discomfort Comes Afterwards

The authors report on a patient with recurrent angina at rest and on exertion 2 years after percutaneous revascularisation of the first diagonal branch (D1). Invasive coronary angiography with full functional testing was planned with the tentative diagnosis of coronary vascular dysfunction. Coronary angiography with functional testing revealed a haemodynamically significant intermediate stenosis at the D1-left anterior descending artery bifurcation. Optical coherence tomography demonstrated neointimal bridging and accelerated downstream atherosclerosis that was induced by protrusion of the previously implanted stent into the main branch. Although the overhanging stent was considered insignificant at first, it caused significant discomfort after 2 years. After provisional stenting of the main branch with crushing of the protruding stent and continuous medical treatment, the patient remained free of recurrent angina.

Methotrexate Therapy Promotes Cell Coverage and Stability in in-Stent Neointima

PURPOSE

Anti-proliferative drugs released from drug-eluting stents delay cell coverage and vascular healing, which increases the risk of late stent thrombosis. We assessed the potential effects of systemic methotrexate (MTX) on cell coverage, vascular healing and inflammation activation in vivo and in vitro.

METHODS

We applied MTX in the right common carotid artery in a rabbit stenting model to determine the impact on cell coverage and inflammation activation using a serial optical coherence tomography (OCT) analysis and elucidated the molecular mechanism of MTX in human umbilical vein endothelial cells (HUVECs).

RESULTS

Low-dose MTX promoted the development of cell coverage and vascular healing, which was associated with fewer uncovered struts (%) and cross-sections with any uncovered struts (%) at 4 weeks of stenting. The MTX group also exhibited lower rates of heterogeneity, microvessels and per-strut low-signal-intensity layers, indicating neointimal instability at 12 weeks of stenting. In vitro, low-dose MTX strongly inhibited HUVEC apoptosis, promoted proliferation and inhibited inflammatory activation by targeting the phosphoinositide 3-kinase (PI3K)/AKT signalling pathway.

CONCLUSION

Low-dose MTX may be a key means of promoting early cell coverage via the inhibition of the inflammatory response and stability of neointima by targeting inflammatory pathways after stent implantation.

Coronary Stent Healing in Cancer Patients-An Optical Coherence Tomography Perspective

Objective: This study assessed stent healing patterns and cardiovascular outcomes by optical coherence tomography (OCT) in cancer patients after drug-eluting stent (DES) placement.

Background: Cancer treatment, owing to its cytotoxic and antiproliferative effects, could delay stent healing and increase stent thrombosis risk, especially when dual antiplatelet therapy (DAPT) is discontinued early for oncological treatment. OCT can assess stent endothelialization and other healing parameters, which may provide clinical guidance in these challenging scenarios.

Methods: This single-center retrospective study enrolled all cancer patients who underwent OCT for assessment of vascular healing patterns after prior DES placement from November 2009 to November 2018. Primary study endpoints were stent healing parameters, including stent coverage, apposition, degree of expansion, neointimal hyperplasia heterogeneity, in-stent restenosis, stent thrombosis, and overall survival (OS).

Results: A total of 67 patients were included in this study. Mean time between DES placement and OCT evaluation was 154 ± 82 days. Stent healing matched published values for DES in non-cancer patients (P ≥ 0.063). At 1 year, the OS was 86% (95% confidence interval [CI]: 78–96%) with 0% incidence of acute coronary syndrome. Advanced cancers and active chemotherapies were associated with inferior OS (P = 0.024, hazard ratio [HR]: 3.50, 95% CI: 1.18–10.42 and P = 0.026, HR: 2.65, 95% CI: 1.13–6.22, respectively), while stent healing parameters were unassociated with OS. Forty-one patients (61%) had DAPT duration ≤6 months.

Conclusions: Stent healing of contemporary DES appears similar in cancer and non-cancer patients. Cardiovascular risk of cancer patients after DES placement can be managed to facilitate timely cancer therapies, as the underlying malignancy and active chemotherapy ultimately determine survival.

Association between in-stent neointimal characteristics and native coronary artery disease progression

Background and aims

The prognosis of stented lesions differs according to in-stent neointimal characteristics on optical coherence tomography (OCT). In particular, patients who show in-stent heterogeneous neointima are associated with a higher incidence of target lesion revascularization (TLR) compared with those who show in-stent non-heterogeneous neointima. However, the relationship between in-stent neointimal characteristics and native coronary atherosclerosis progression has not been clearly elucidated. The study aimed to investigate the relationship between in-stent neointimal characteristics and progression of native atherosclerosis.

Methods

The neointimal characteristics of 377 patients with 377 drug-eluting stents (DESs) were quantitatively and qualitatively assessed using OCT. The OCT-based neointima was categorized as homogeneous (n = 207), heterogeneous (n = 93), and layered (n = 77). The relationship of non-target lesion revascularization (non-TLR) with neointimal characteristics was evaluated after OCT examination of the stents.

Results

After a median follow-up duration of 40.0 months, patients with heterogeneous neointima showed significantly higher non-TLR rates than those with homogeneous neointima and tended to have higher non-TLR rates than those with layered neointima (heterogeneous vs. homogeneous:14.0% vs. 8.7%, p = 0.046; heterogeneous vs. layered neointima:14.0% vs. 7.8%, p = 0.152). Multivariate analysis showed that the independent determinants for non-TLR were heterogeneous neointima (HR: 2.237, 95% CI: 1.023–4.890, p = 0.044) and chronic kidney disease (hazard ratio [HR]: 8.730, 95% CI: 2.175–35.036, p = 0.002).

Conclusions

The heterogeneous neointima in DES-treated lesions was associated with a higher incidence of non-TLR and target lesion failure. This finding suggests that the neointimal pattern may reflect the progression of the native lesion.

Impact of diabetes mellitus on vascular healing process after everolimus-eluting stent implantation: An optical coherence tomography study

BACKGROUND/PURPOSE

To study the impact of diabetes mellitus (DM) on vascular healing process after implantation of everolimus-eluting stent (EES).

METHODS/MATERIALS

Data from 3 prospective studies (HEAL-EES, REVER, and RESERVOIR), including patients with EES implantation and OCT follow-up, were merged. Differences in vascular healing process assessed by OCT were compared between DM and non-DM using generalized estimating equations. Neointimal proliferation, neointimal signal pattern (high, low, and layered), and uncovered/malapposed struts were evaluated.

RESULTS

A total of 96 lesions (61 DM lesions and 35 non-DM lesions) were included. Mean OCT follow-up time was 8.9 ± 1.5 months and comparable between groups. DM were older, high frequently female and acute coronary syndrome, and received smaller stent than non-DM. No differences were observed in quantitative vascular healing process between groups. However, DM exhibited higher low and layered signal pattern neointima compared to non-DM at lesion level (p = 0.030) and cross-section level (p < 0.001). Uncovered/malapposed struts were comparable between groups.

CONCLUSIONS

Quantitative vascular healing process was comparable between groups. However, DM was significantly associated with low signal pattern, which is characteristic of focal inflammation, after EES implantation. Further study might be required to study relationship between neointimal signal pattern and clinical events.

Early coronary healing in ST segment elevation myocardial infarction: sirolimus-eluting stents vs. drug-coated balloons after bare-metal stents. The PEBSI-2 optical coherence tomography randomized study

OBJECTIVES

Drug-coated balloons (DCBs) have theoretical advantages over drug-eluting stents (DESs) to facilitate stent healing. We studied whether, in patients undergoing primary coronary interventions (pPCIs), a strategy of DCB after bare-metal stent improves early healing as determined by optical coherence tomography (OCT) compared with new-generation DES.

METHODS

pPCI patients were randomized (1:1) to treatment with new-generation sirolimus-eluting stents (DES group) or DCB-strategy. Vessel healing was assessed by OCT at 90 days.

RESULTS

Fifty-three patients were randomized (26 DES vs. 27 DCB). At 90 days, both strategies showed a low rate of uncovered struts (3.2 vs. 3.2%, P = 0.64) and a very high and similar rate of covered and apposed struts (96.6 vs. 96.1%, respectively; P = 0.58). However, DCB group had a significantly lower rate of major coronary evaginations (68 vs. 37%, P = 0.026), and more frequently developed a thin homogeneous neointimal layer (20 vs. 70.4%, P = 0.001) suggesting distinct superior healing at 3 months compared to DES.

CONCLUSIONS

In pPCI both, sirolimus-DES and DCB-strategy, provide excellent strut coverage at 3 months. However, DCB ensures more advanced and optimal stent healing compared to sirolimus-DES. Further research is needed to determine whether, in patients undergoing pPCI, DCB offers superior long-term clinical and angiographic outcomes than new-generation DES (NCT03610347).

Multi-modality intravascular imaging for guiding coronary intervention and assessing coronary atheroma: the Novasight Hybrid IVUS-OCT system

Intravascular imaging has evolved alongside interventional cardiology as an adjunctive tool for assessing plaque pathology and for guiding and optimising percutaneous coronary intervention (PCI) in challenging lesions. The two modalities which have dominated the field are intravascular ultrasound (IVUS), which relies on sound waves and optical coherence tomography (OCT), relying on light waves. These approaches however have limited efficacy in assessing plaque morphology and vulnerability that are essential for guiding PCI in complex lesions and identifying patient at risk that will benefit from emerging therapies targeting plaque evolution. These limitations are complementary and, in this context, it has been recognised and demonstrated in multi-modality studies that the concurrent use of IVUS and OCT can help overcome these deficits enabling a more complete and accurate plaque assessment. The Conavi Novasight Hybrid IVUS-OCT catheter is the first commercially available device that is capable of invasive clinical coronary assessment with simultaneously acquired and co-registered IVUS and OCT imaging. It represents a significant evolution in the field and is expected to have broad application in clinical practice and research. In this review article we present the limitations of standalone intravascular imaging techniques, summarise the data supporting the value of multimodality imaging in clinical practice and research, describe the Novasight Hybrid IVUS-OCT system and highlight the potential utility of this technology in coronary intervention and in the study of atherosclerosis.

Inflammation as a determinant of healing response after coronary stent implantation

Cardiovascular disease remains the leading cause of death and morbidity worldwide. Inflammation plays an important role in the development of atherosclerosis and is associated with adverse clinical outcomes in patients after percutaneous coronary interventions. Data on stent elements that lead to excessive inflammatory response, proper identification of high-risk patients, prevention and treatment targeting residual inflammatory risk are limited. This review aims to present the role of inflammation in the context of evolving stent technologies and appraise the potential imaging modalities in detection of inflammatory response and anti-inflammatory therapies.

The association of diabetes mellitus with neointimal formation following deployment of second-generation drug-eluting stents: an optical coherence tomographic study

OBJECTIVES

The purpose of this study was to evaluate the association of diabetes mellitus (DM) with neointimal formation after implantation of second-generation drug-eluting stent (DES) visualized by optical coherence tomography (OCT).

METHODS

Patients with single de novo coronary artery disease treated with second-generation DES between June 2014 and June 2017 in our department underwent OCT examination at 1-year follow-up and were enrolled in this retrospective study. The primary end point was in-stent mean neointimal thickness (MNT), and secondary end points included uncovered stent strut, minimal lumen area (MLA), neointimal burden, neointimal hyperplasia (NIH) patterns and stent thrombosis (ST) after 1 year of OCT follow-up.

RESULTS

A total of 68 patents with DM (DM group) and 216 patients without DM (non-DM group) were enrolled. At 1-year follow-up, the DM group compared with the non-DM group, showed: MNT [160 (85-245) μm vs. 120 (60-220) μm, P = 0.038] and neointimal burden [21.4 (8.3-30.1)% vs. 14.0 (5.7-26.1)%, P = 0.023] to be significantly increased. Concurrently, MLA [4.60 (3.53-6.06) mm vs. 5.76 (4.28-7.20) mm2, P = 0. 0.002] was significantly reduced. Interestingly, the degree of uncovered struts (7.3 ± 7.1% vs. 7.7 ± 6.7%, P = 0.704), NIH patterns (P = 0.984), and ST (7.9% vs. 7.4%, P = 0.88) were comparable between the two groups. After propensity score matching, the MNT [160 (90-240) μm vs. 110 (60-220) μm, P = 0.048] and neointimal burden [21.4 (8.3-30.1)% vs. 15.4 (5.6-26.3)%, P = 0.044] remained significantly different in the DM compared to the non-DM group.

CONCLUSION

DM leads to significant increase in MNT and neointimal burden even with second-generation DES, nevertheless stent strut coverage, ST and NIH characteristics remained comparable among the cohorts at 1-year.

Neointima characteristics as a prognostic marker for drug-coated balloon angioplasty in patients with in-stent restenosis: an optical coherence tomography study

BACKGROUND

Research has shown that the prognosis of in-stent restenosis (ISR) lesions after drug-coated balloon (DCB) angioplasty can differ in relation to in-stent neointimal characteristics. However, changes in neointima characteristics after DCB have not been studied. This study sought to investigate changes in neointima characteristics after DCB for ISR.

METHODS

From the Yonsei Optical Coherence Tomography (OCT) registry, data on DCBs performed in patients with ISR were collected. Neointima characteristics were categorized as homogeneous, heterogeneous, layered neointima, and neoatherosclerosis in each OCT procedure. Homogeneous and layered neointima were classified as a favorable neointima, while heterogeneous neointima and neoatherosclerosis were classified as an unfavorable neointima. The data of 67 ISR patients were analyzed.

RESULTS

The median duration between initial and follow-up OCT was 9.6 months. Patients with homogeneous and layered neointima on the initial OCT before DCB mostly appeared as homogeneous (66.7 and 68.2%, respectively) on the follow-up OCT, whereas most of the patients with heterogeneous neointima on the initial OCT remained unaltered (70%). Patients with unfavorable neointima at either the initial (P = 0.023) or the follow-up OCT (P = 0.037) had a worse major adverse cardiovascular event-free survival than the other patients. Patients who showed unfavorable neointima at both the initial and the follow-up OCT had the worst event-free survival (P = 0.038).

CONCLUSIONS

The follow-up OCT neointimal characteristics after DCB for ISR was associated with initial OCT characteristics. Sustained unfavorable neointima in serial OCT imaging may reflect poor prognosis in patients with ISR treated with DCB.

Clinical implication of neointimal burden in in-stent restenosis treated with drug-coated balloon

BACKGROUND

Although drug-coated balloon (DCB) angioplasty is a well-established drug-eluting stent (DES) in-stent restenosis (ISR) strategy, there are minimal data regarding the association of neointimal burden on optical coherence tomography (OCT) before and after DCB and adverse clinical events. This study aimed to investigate the clinical impact of neointimal burden measured with OCT in patients with DES ISR after DCB angioplasty.

METHODS

From 2010 through 2013, a total of 122 patients with 122 ISR lesions were treated with DCB, which was preceded and followed by OCT examination. Major adverse cardiac events (MACE, a composite occurrence of cardiovascular cardiac death, nonfatal myocardial infarction [MI], or target lesion revascularization [TLR]) were evaluated.

RESULTS

MACE occurred in 27 patients (4 nonfatal MIs and 23 TLRs) during the follow-up (median: 55.3 months, interquartile range 43.1-66.0). The mean lumen area was significantly smaller (3.21 ± 2.42 mm² vs. 4.80 ± 2.53 mm² , p = .005) and the mean percentage of neointimal volume derived by OCT was greater (49.3 ± 9.2% vs. 38.3 ± 17.5%, p = .006) in patients with MACE before DCB angioplasty. The pre-procedural mean percentage of neointimal volume (cut-off 50%, area under the receiver operating characteristic [ROC] curve = 0.644, 95% confidence interval [CI] = 0.531-0.758, p = .022) and post-procedural mean percentage of neointimal volume (cut-off 25%, area under ROC curve = 0.659, 95% CI = 0.546-0.773, p = .012) were identified as significant parameters to predict MACE.

CONCLUSION

The OCT-derived mean percentages of neointimal volume before and after DCB angioplasty can be important parameters for predicting future MACE in patients with DES ISR.

Characteristics of recurrent in-stent restenosis after second- and third-generation drug-eluting stent implantation

BACKGROUND

In second- and third-generation drug-eluting stent (DES) era, in-stent restenosis (ISR) is not commonly seen. However, a few patients still need repeat revascularizations for recurrent ISR even after second- and third-generation DES implantation.

METHODS

From January 2012 to March 2017, 2339 lesions underwent second- and third-generation DES (Nobori, Promus Element, Resolute Integrity, Xience, Ultimaster and Synergy) implantation, of which 95 lesions (4.1%) underwent revascularization for first ISR. All lesions were divided into two groups of recurrent ISR group and non-recurrent ISR group. After successful optical coherence tomography (OCT) guided revascularization for all lesions, we investigated characteristics of recurrent ISR, and 2 years follow-up were completed.

RESULTS

The mean age was 70.8 ± 11.7 years, and 73.2% were males. Among 56 DES-ISR lesions which were assessed by OCT, recurrent ISR was seen in 33.9% (N = 19) at 2 years follow-up after revascularization for first ISR. Serum low-density lipoprotein-cholesterol (LDL-C) level was higher in recurrent ISR group compared with non-recurrent ISR group (114.1 ± 53.9 mg/dl vs. 90.9 ± 27.8 mg/dl, P = 0.04) and heterogeneous tissue pattern was more frequently found in recurrent ISR group compared with non-recurrent ISR group (63.2% vs. 27.0%, P = 0.03). Multivariate analysis identified a heterogeneous tissue pattern (odds ratio 3.71; 95% confidence interval 1.09-12.59; P = 0.03) as an independent predictor of recurrent restenosis.

CONCLUSION

Recurrent ISR of second- and third-generation DES was associated with heterogeneous tissue pattern of first ISR, and high LDL-C level was associated with recurrence.

The effect of the debulking by excimer laser coronary angioplasty on long-term outcome compared with drug-coating balloon: insights from optical frequency domain imaging analysis

This study evaluated the 1-year efficacy of excimer laser coronary angioplasty (ELCA) before drug-coated balloon (DCB) dilatation for the treatment of in-stent restenosis (ISR). Forty consecutive patients with ISR were treated by DCB with or without the use of ELCA (ELCA plus DCB, N = 20; DCB alone, N = 20). Debulking efficiency (DE) value was defined as the neointima area on optical frequency domain imaging (OFDI) debulked by ELCA. The patients in the ELCA plus DCB group were divided into two groups (greater DE (GDE), N = 10; smaller DE (SDE), N = 10) based on the median value of DE. Thereafter, the ISR segment was prepared with a scoring balloon, followed by DCB. At follow-up, binary restenosis and target lesion revascularization (TLR) were evaluated. There were no significant differences in baseline characteristics such as age, comorbidity, and ISR type. Overall, the incidence of neoatherosclerosis in the ISR segment was 17.5%. Post-PCI, acute gain of minimum lumen diameter on quantitative coronary angiography and of minimum lumen area on OFDI was numerically higher in the GDE than in the SDE and the DCB alone group. At follow-up, the occurrences of binary restenosis and TLR in the ELCA plus DCB group were 20.0% and 10.0%; these values in the DCB alone group were 20.0% and 20.0%, respectively. Two patients from the SDE and none from the GDE developed TLR. DCB alone treatment was inferior to ELCA plus DCB treatment. However, greater ELCA debulking might be required to obtain optimal outcomes.

Short-term stent coverage of second-generation zotarolimus-eluting durable polymer stents: Onyx one-month optical coherence tomography study

Introduction

To date the early strut coverage with the second-generation durable-polymer ONYX zotarolimus-eluting stent (O-ZES) is unknown.

Aim

Optical coherence tomography (OCT) assessed the strut coverage of O-ZES at thirty-day follow-up.

Material and methods

OCT was performed after implantation and at 1-month follow-up in 15 patients treated with O-ZES.

Results

Mean patient age was 67 ±7 years (73% males). The clinical presentation consisted of acute coronary syndromes (n = 13) and stable coronary disease (n = 2). Four (26%) patients had diabetes. OCT analysis was performed at baseline and 1-month follow-up in all stents. 378 cross-sections with 3582 struts were assessed at baseline and 3661 at follow-up. At follow-up, 88% struts were covered by tissue with a median thickness 37.91 μm (IQR: 22.32–64.15). Median in-stent area obstruction by neointima was 2.64% (IQR: 1.70–4.84). From the total stent covered area, 92.3% showed complete strut coverage. Homogeneous tissue was observed in 74% of cases. There were no differences in minimal lumen area (5.07 ±1.08 mm² vs. 4.81 ±0.94 mm², p = 0.125) or minimal stent area (4.95 ±1.22 mm² vs. 4.92 ±0.99 mm²) at baseline and at follow-up. There were no differences in the rate of strut malapposition (4.3% vs. 5.7%, p = 0.417). For all stents, malapposition volume was 47.9 mm³ at baseline and 51.7 mm³ at follow-up, giving the late acquired stent malapposition volume of 3.8 mm³.

Conclusions

The second-generation durable polymer O-ZES showed favorable vessel healing at 30-day OCT follow-up.

Different Neointimal Pattern in Early vs. Late In-Stent Restenosis and Clinical Outcomes After Drug-Coated Balloon Angioplasty - An Optical Coherence Tomography Study

BACKGROUND

There are few data of clinical outcomes after drug-coated balloon (DCB) angioplasty according to neointimal characteristics. This study investigated long-term clinical outcomes according to timing of in-stent restenosis (ISR) and neointimal characteristics in patients with drug-eluting stent (DES) ISR after DCB angioplasty.

METHODS AND RESULTS

In all, 122 patients (122 ISR lesions), treated with DCB under optical coherence tomography (OCT) examination before and after DCB, were categorized as early ISR (<12 months; E-ISR; n=21) and late ISR (≥12 months; L-ISR; n=101). Associations between OCT-based neointima characteristics and period of ISR, as well as clinical outcomes after DCB were evaluated. Major adverse cardiac events (MACE) were a composite of cardiac death, non-fatal myocardial infarction, or target lesion revascularization (TLR). Quantitative parameters of the neointima were similar, but qualitative characteristics showed significant differences between the E-ISR and L-ISR groups. The incidence of MACE (33.3% vs. 20.8%; P=0.069) and TLR (33.3% vs. 18.5%; P=0.040) was higher in the E-ISR group. In addition, the incidence of MACE was significantly higher for heterogeneous than non-heterogeneous neointima (43.7% vs. 19.6%; P=0.018), but was not significantly associated with neoatherosclerosis (33.4% vs. 18.4%; P=0.168).

CONCLUSIONS

DCB angioplasty is less effective for heterogeneous neointima in DES ISR. OCT-based neointimal evaluation may be helpful in guiding treatment of DES ISR.

Correlation between pre-procedural plaque morphology and patterns of in-stent neointimal hyperplasia at 1-year follow-up in patients treated with new-generation drug-eluting stents: An optical coherence tomography based analysis

INSTRUCTION

Several factors affect the in-stent intimal healing process after drug-eluting stents (DESs) implantation. We hope to investigate the influence of plaque characteristics on subsequent heterogeneous neointimal hyperplasia (NIH) using optical coherence tomography (OCT).

METHODS

The study population consisted 217 patients with single-vessel de novo lesions who underwent both pre-procedural OCT scan and 12-month follow-up OCT examination. NIH is defined as at least five consecutive cross-sectional images with no less than 100µm neointimal thickness. According to OCT follow-up, patients were divided into three groups: neointima-covered group, homogeneous, and heterogeneous NIH group.

RESULTS

102 patients were categorized in neointima-covered group, 91 and 24 patients in homogeneous and heterogeneous group, respectively. Time interval between OCT scans was similar (P = 0.55). No significant differences in the patients' age, gender, comorbidities, laboratory findings, procedural, and lesion-related findings were found among these three groups. Heterogeneous group tended to have more subjects presented as acute coronary syndrome (ACS) (P = 0.04) and mean macrophage grade was higher in this group (P = 0.01). While no statistically significant difference concerning mean intimal thickness (P = 0.21) or neointimal burden (P = 0.73) was found between homogeneous and heterogeneous group. Multivariate logistic regression analysis showed that mean macrophage grade (OR: 2.26, 95%CI: 1.12 to 4.53, P = 0.02) and initial clinical presentation of ACS (OR: 2.81, 95%CI: 1.03 to 7.72, P = 0.04) were significant independent risk factors for heterogeneous NIH.

CONCLUSION

Mean macrophage grade measured by OCT as a semi-quantitative morphological risk factor, as well as clinical presentation of ACS, was associated with in-stent neointimal heterogeneity after DES implantation.

An optical coherence tomography study of neointimal morphology and strut coverage at different time intervals from implantation of biodegradable polymer-coated sirolimus-eluting stents

OBJECTIVES

The aim of the study was to capture the evolution of neointima after implantation of a biodegradable polymer-coated, sirolimus-eluting, cobalt-chromium coronary stent system (BP-DES).

BACKGROUND

Optical coherence tomography (OCT) suggests that in-stent neointimal morphology influences clinical outcomes after DES implantation.

METHODS

Sixty patients treated with single BP-DES implantation were examined by quantitative coronary angiography (QCA) and OCT at 3, 6, and 12-month follow-up.

RESULTS

Median late lumen loss by QCA (mm) was 0.04 (IQR 0, 0.08), 0.17 (IQR 0, 0.32), and 0.14 (IQR 0.07, 0.31) at 3, 6, and 12-month follow-up respectively (P = 0.03). OCT cross-section multilevel analysis showed uncovered struts in 3.90%, 1.78%, and 0.02% of struts respectively (P = 0.03). The corresponding malapposition rates were 0.12%, 0.04%, and 0%. Lipid-rich neointima was observed only at 12-month follow-up in one restenotic lesion (0.77% cross-sections) that was accountable for the only target vessel revascularization. The homogeneous pattern was prevalent at all three time points, but its incidence displayed an upward trend (3 months: 59%; 6 months: 71%; 12 months: 88%) despite no difference in neointimal volume between 6 and 12 months. Conversely, a trend could be observed of decreasing incidence of heterogeneous pattern as the follow-up length increased.

CONCLUSIONS

In this study of a single-type BP-DES, the majority of stent struts were covered within 3 months from implantation. While the quantitative neointimal accumulation plateaued at 6 months with no further significant increase beyond 6 months, the neointima continued to evolve qualitatively and mature along with better strut coverage between 6 and 12 months after implantation.

Effects of lowest-dose vs. highest-dose pitavastatin on coronary neointimal hyperplasia at 12-month follow-up in type 2 diabetic patients with non-ST elevation acute coronary syndrome: an optical coherence tomography analysis

Current ACC/AHA guidelines recommend high-dose statin therapy after coronary stenting, especially in diabetic patients; however, pitavastatin 4 mg or pitavastatin 1 mg are frequently used after coronary stenting in Asia, even in patients with acute coronary syndrome. We compared the effects of highest-dose and lowest-dose pitavastatin therapy on coronary neointimal hyperplasia at 12-month follow-up in diabetic patients with non-ST-elevation acute coronary syndrome (NSTE-ACS) using optical coherence tomography. A total of 72 diabetic patients with NSTE-ACS were randomized to lowest-dose pitavastatin [1 mg (n = 36)] or highest-dose pitavastatin [4 mg (n = 36)] after everolimus-eluting stent implantation. The primary endpoint was to compare the normalized neointimal volume at 12-month follow-up. Normalized neointimal volume was significantly lower in the pitavastatin 4 mg group (4.00 ± 2.80 vs. 8.24 ± 2.83 mm³/mm, p < 0.01) at 12-month follow-up. There was also significant difference in neointimal area between the pitavastatin 4 mg group and pitavastatin 1 mg group (0.41 ± 0.28 vs. 0.74 ± 0.23 mm², p < 0.01). Improvement of brachial artery flow-mediated dilation (baFMD) was significantly higher in the pitavastatin 4 mg group than in pitavastatin 1 mg group (0.15 ± 0.15 vs. - 0.03 ± 0.19 mm, p < 0.001). In addition, the improvement of adiponectin levels was significantly greater in the pitavastatin 4 mg group than in the pitavastatin 1 mg group (2.97 ± 3.98 vs. 0.59 ± 2.80 μg/mL, p < 0.05). Pitavastatin 4 mg significantly improved inflammatory cytokines and lipid profiles compared to pitavastatin 1 mg during the 12-month follow-up, contributing to the reduction of neointimal hyperplasia and to the improvement of baFMD in diabetic patients with NSTE-ACS requiring coronary stenting. Thus, the administration of pitavastatin 4 mg can be safely and effectively used in high-risk patients requiring coronary stenting. Trial registration NCT02545231 (Clinical Trial registration information: https://clinicaltrials.gov/ct2/show/NCT02545231 ).

The impact of acute coronary syndrome on late drug-eluting stents restenosis: Insights from optical coherence tomography

The aim of the study was to investigate the optical coherence tomography (OCT)-identified difference of in-stent restenosis (ISR) tissue characteristics between patients with and without acute coronary syndrome (ACS) at index intervention.The retrospective study included 80 patients with 85 drug-eluting stent (DES) restenosis lesions. Subjects were classified according to clinical presentation at the time of de-novo lesion intervention, namely ACS and non-ACS. OCT was performed at 5 years follow-up. The frequency of malapposition, neointimal characteristics, thrombus, and minimal stent area (MSA) were evaluated.ACS group consisted of 48 (60%) patients. The mean duration from initial intervention to OCT study was 66.15 months. Malapposition was more frequent in the ACS group (25.5% vs 2.9%, P = .006), as well as a higher prevalence of thrombus in the ACS group (21.6% vs 0%, P = .015). MSA of ACS group was significantly less than that of non-ACS group (4.99 ± 1.80 vs 5.62 ± 2.08 mm, P = .018). Compared with non-ACS group, only MI group was related to smaller MSA (4.37 ± 1.39 vs 5.62 ± 2.08 mm, P = .048); The unstable angina (UA) group was not associated with a decreased MSA. The occurrence of neoatherosclerosis tended to be higher in ACS group (60.8% vs 41.2%, P = .076).In DES restenosis, an ACS presentation at initial intervention is associated with a higher incidence of malapposition, thrombus, and smaller MSA.

Formation and Transformation of Neointima after Drug-eluting Stent Implantation: Insights from Optical Coherence Tomographic Studies

After coronary stent implantation, neointima formation resembles the wound healing process as it involves the sequential processes of inflammation, granulation, and remodeling. Because antiproliferative drugs and polymers of drug-eluting stents (DESs) delay vascular healing compared with bare metal stents, fibrin deposition can remain long after stent implantation, or inflammation can be excessive. Delayed vascular healing can be associated with adverse clinical outcomes including DES thrombosis or restenosis, and poor endothelization of DES neointima can accelerate neoatherosclerotic change inside the neointima, further contributing to luminal restenosis or neointimal instability. Despite the lack of correlation between pathologic and optical coherence tomography (OCT) findings, OCT assessments of neointima under various circumstances can reveal vascular responses to stent therapy. Homogeneous, heterogeneous, and layered neointima patterns can be recognized by OCT and can change with time. Homogeneous neointima might be associated with better clinical outcomes after DES implantation, whereas non-homogeneous neointima or neoatherosclerotic change can be associated with poorer clinical outcomes. However, limited data are currently available, and further studies are required to comprehensively address these questions.

Impact of Cigarette Smoking and Smoking Cessation on Stent Changes as Determined by Optical Coherence Tomography After Sirolimus Stent Implantation

There is debate regarding whether smoking results in microstructural changes after stenting. The aim of this study was to evaluate the microstructural changes after stenting in patients with different smoking statuses. We retrospectively identified 220 sirolimus-eluting stents in 179 patients who underwent follow-up optical coherence tomography examination 12 months after sirolimus stenting. Subjects were classified as current smokers (CS, n = 31), smoking cessation ≤1 year (n = 36), smoking cessation >1 year (SC > 1Y, n = 27), and never smokers (NS, n = 85). The neointimal hyperplasia (NIH) area was larger in CS than in NS (1.04 ± 0.72 mm² vs 0.96 ± 0.68 mm²; p = 0.04). The incidence of lipid-laden neointima was lower in SC > 1Y patients (1.6%) than in all other patients (NS: 3.9%, p = 0.002; CS: 3.0%, p = 0.073; SC1Y: 5.0%, p <0.001). Smoking cessation level was negatively correlated with NIH (B = -0.154; 95% confidential interval -0.187, -0.121; p <0.001) and independently associated with the presence of homogeneous neointima (odds ratio: 1.414; 95% confidential interval 1.145, 1.745; p = 0.001). The incidence of malapposed struts was higher in CS than in NS (3.2% vs 1.6%; p = 0.004). However, smoking cessation patients showed a decreased trend in the incidence of malapposed struts (p = 0.0003). In conclusion, continued smoking increases NIH and the incidence of malapposed struts. However, smoking cessation slows down NIH progression and decreases the incidence of malapposed struts. Smoking cessation promotes vascular healing after stenting.

Three-month evaluation of strut healing using a novel optical coherence tomography analytical method following bioresorbable polymer everolimus-eluting stent implantation in humans: the TIMELESS study

AIMS

Bioresorbable polymer drug-eluting stent technologies have been considered to have the potential to enhance vascular healing by reducing polymer exposure to the vessel wall, potentially allowing the earlier discontinuation of dual antiplatelet therapy. At present, the early vascular healing response to this type of technologies is still unclear.

PATIENTS AND METHODS

The TIMELESS study is a multicenter, prospective, single-arm study that enrolled real-world patients undergoing percutaneous coronary intervention. All patients underwent Synergy stent implantation, which consists of a platinum-chromium platform coated with an ultra-thin abluminal bioabsorbable poly-D,L-lactide-co-glycolide polymer-eluting everolimus.

RESULTS

A total of 37 patients were included in the study. The majority of the patients underwent percutaneous coronary intervention because of acute coronary syndromes. At 3 months, angiographic follow-up showed a percentage diameter of stenosis of 8.1±7.5% and an angiographic late loss of 0.03±0.24 mm. In all analyzed struts, less than 1% of struts were definitely uncovered or covered with fibrin, 12.5% (5.0-18.5%) showed evidence of partial coverage, and the remaining (∼85%) were fully covered. No stent thrombosis was observed up to 12 months of clinical follow-up.

CONCLUSION

In a real-world population, the implantation of a bioresorbable polymer drug-eluting stent resulted in almost complete strut coverage throughout the entire stent length at 3 months. The clinical implications for antiplatelet therapy and outcomes should be investigated further.

Investigation of enhanced hemocompatibility and tissue compatibility associated with multi-functional coating based on hyaluronic acid and Type IV collagen

The biocompatibility of cardiovascular devices has always been considered crucial for their clinical efficacy. Therefore, a biofunctional coating composed of Type IV collagen (CoIV) and hyaluronan (HA) was previously fabricated onto the titanium (Ti) substrate for the application of promoting vascular smooth muscle cell contractile phenotype and improving surface endothelialization. However, the anti-inflammation property, blood compatibility and in vivo tissue compatibility of the HA/CoIV coating, as paramount consideration of cardiovascular materials surface coating, have not been investigated. Thus, in this study, the three crucial properties of the HA/CoIV coating were tested. The platelet adhesion/activation test and the dynamic whole blood experiment implied that the HA/CoIV coating had better blood compatibility compared with Ti substrate and pure CoIV coating. The macrophage adhesion/activation and inflammatory cytokine release (tumor necrosis factor-alpha and interleukin-1) results indicated that the HA/CoIV coating could significantly improve the anti-inflammation property of the Ti substrate. The in vivo implantation of SD rats for 3 weeks' results demonstrated that the HA/CoIV coating caused milder tissue response. All these results suggested that the multi-functional HA/CoIV coating possessed good biocompatibility. This research is anticipated to be potentially applied for the surface modification of cardiovascular stents.

Optical Coherence Tomography of De Novo Lesions and In-Stent Restenosis in Coronary Saphenous Vein Grafts (OCTOPUS Study)

BACKGROUND

The OCTOPUS registry prospectively evaluates the procedural and long-term outcomes of saphenous vein graft (SVG) PCI. The current study assessed the morphology of de novo lesions and in-stent restenosis (ISR) in patients undergoing PCI of SVG.

METHODS AND RESULTS

Optical coherence tomography (OCT) of SVG lesions in consecutive patients presenting with stable CAD and ACS was carried out. Thirty-nine patients (32 de novo and 10 ISR lesions) were included in the registry. ISR occurred in 5 BMS and 5 DES. There were no differences in the presence of plaque rupture and thrombus between de novo lesions and ISR. Lipid-rich tissue was identified in both de novo lesions and in ISR (75% vs. 50%, P=0.071) with a higher prevalence in BMS than in DES (23% vs. 7.5%; P=0.048). Calcific de novo lesions were detected in older grafts as compared with non-calcific atheromas (159±57 vs. 90±62 months after CABG, P=0.001). Heterogeneous neointima was found only in ISR (70% vs. 0, P<0.001) and was observed with similar frequency in both BMS and DES (24% vs. 30%, P=0.657). ISR was detected earlier in DES than BMS (median, 50 months; IQR, 18-96 months vs. 27 months; IQR, 13-29 months, P<0.001).

CONCLUSIONS

OCT-based characteristics of de novo and ISR lesions in SVG were similar except for heterogeneous tissue, which was observed only in ISR. (Circ J 2016; 80: 1804-1811).

Clinical Characteristics and Prognosis of Peri-strut Low-intensity Area Detected by Optical Coherence Tomography

Background:

Peri-strut low-intensity area (PLIA) is a typical image pattern of neointima detected by optical coherence tomography (OCT) after stent implantation. However, few studies evaluated the predictors and prognosis of the PLIA; therefore, we aimed to explore the genesis and prognosis of PLIA detected by OCT in this study.

Methods:

Patients presenting neointimal hyperplasia documented by OCT reexamination after percutaneous coronary intervention were prospectively included from 2009 to 2011. Peri-strut intensity was analyzed and classified into two patterns: Low-intensity and high-intensity. Clinical characteristics were analyzed to assess their contribution to peri-strut intensity patterns. Follow-up were performed in patients who did not receive revascularization during OCT reexamination, and the prognosis of the patients was evaluated.

Results:

There were 128 patients underwent OCT reexamination after stent implantation included in the study. PLIA was detected in 22 (17.2%) patients. The incidence of PLIA was positively correlated with serum triglyceride (odds ratio [OR]: 2.11, 95% confidence interval [CI]: 1.14–3.90, P = 0.017), low-density lipoprotein (OR: 2.61, 95% CI: 1.22–5.66, P = 0.015), history of cerebrovascular disease (OR: 101.11, 95% CI: 6.54–1562.13, P < 0.001), and initial clinical presentation of acute coronary syndrome (ACS, OR: 18.77, 95% CI: 2.73–128.83, P = 0.003) while negatively correlated with stent implantation time (OR: 0.57, 95% CI: 0.33–0.98, P = 0.043). The median follow-up was longer than 3.8 years. Major adverse cardiovascular events (MACEs) occurred in 7 (7.3%) patients while showed no correlation with PLIA. A total of 17 (17.7%) patients experienced unstable angina (UA) and showed significant correlation with PLIA (hazard ratio: 6.16, 95% CI: 1.25–30.33, P = 0.025).

Conclusions:

PLIA detected by OCT was positively correlated with higher serum lipid level, history of cerebrovascular disease and initial presentation of ACS, and negatively correlated with stent implantation time. Patients with PLIA were more likely to have UA than those with high-intensity while no significant difference was found in MACEs.

Neoatherosclerosis: Coronary stents seal atherosclerotic lesions but result in making a new problem of atherosclerosis

Chronic inflammation of the native vessel wall with infiltration of lipid-laden foamy macrophages through impaired endothelium results in atherosclerosis. Percutaneous coronary intervention, including metallic stent implantation, is now widely utilized for the treatment of atherosclerotic lesions of the coronary artery. Bare-metal stents and the subsequently developed drug-eluting stents seal the atherosclerosis and resolve lumen stenosis or obstruction of the epicardial coronary artery and myocardial ischemia. After stent implantation, neointima proliferates within the stented segment. Chronic inflammation caused by a foreign body reaction to the implanted stent and subsequent neovascularization, which is characterized by the continuous recruitment of macrophages into the vessel, result in the transformation of the usual neointima into an atheromatous neointima. Neointima with an atherosclerotic appearance, such as that caused by thin-cap fibroatheromas, is now recognized as neoatherosclerosis, which can sometimes cause in-stent restenosis and acute thrombotic occlusion originating from the stent segment following disruption of the atheroma. Neoatherosclerosis is emerging as a new coronary stent-associated problem that has not yet been resolved. In this review article, we will discuss possible mechanisms, clinical challenges, and the future outlook of neoatherosclerosis.

Novel sirolimus-eluting stent Prolim® with a biodegradable polymer in the all-comers population: one year clinical results with quantitative coronary angiography and optical coherence tomography analysis

BACKGROUND

The aim of this study was to assess the safety and the efficacy of the novel sirolimus-eluting Prolim® stent with a biodegradable polymer in the all-comers population.

METHODS

We prospectively enrolled all patients with stable coronary artery disease or acute coronary syndrome treated with Prolim® stent between January and December 2013 in two interventional cardiology centers in Poland. Angiographic control was planned at 12 months, in which 15 % of patients (randomly chosen) underwent optical coherence tomography imaging. The primary end-point was the cumulative rate of cardiac death, myocardial infarction, and target lesion revascularization at 12 months.

RESULTS

There were 204 patients enrolled, in whom 238 Prolim® stents were deployed (1.17 stent per patient). The mean age was 68 ± 10 years and 32.8 % were females. The examined stent was implanted in 5.9 % in STEMI patients, in 21.6 % - in NSTE-ACS and in 72.5 % - in patients with stable coronary artery disease. The Prolim® stent was most frequently implanted in right coronary artery (38.2 %) followed by left anterior descending artery (34.0 %). The cumulative major adverse cardiovascular events rate at 12 months was 6.9 %, and the clinically-driven target lesion revascularization rate - 5.4 %. At 12 months in quantitative coronary angiography the late lumen loss was 0.21 ± 0.18 mm, and in optical coherence tomography the mean neointima burden was 24.6 ± 8.6 %.

CONCLUSIONS

Sirolimus-eluting Prolim® stent with a biodegradable polymer is a feasible device with a very good safety profile and long-term clinical effectiveness.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT02545985 .

Neointimal Coverage After Drug-Eluting Stent Implantation: Insights from Optical Coherence Tomography

Optical coherence tomography (OCT), which provides high-resolution imaging of the coronary vasculature, has provided novel insights into the pathophysiology of neointimal growth after drug-eluting stent (DES) implantation. The natural history, time course, and characteristics of strut coverage with neointima have been well defined by OCT. Pathology studies have identified strut coverage as a risk factor for stent thrombosis, and OCT studies have shown that next-generation DES have better strut coverage than first-generation DES. By reducing the incidence of stent thrombosis, improved strut coverage should lead to favorable clinical safety and the feasibility of shorter-duration dual antiplatelet therapy after DES implantation.

Optical coherence tomographic evaluation of the effect of cigarette smoking on vascular healing after sirolimus-eluting stent implantation

Cigarette smoking is known to be deleterious to patients with coronary artery disease; however, the effect of smoking on vascular responses after coronary drug-eluting stent implantation is unknown. We sought to examine vascular response after sirolimus-eluting stent implantation in patients with ongoing smoking using optical coherence tomography, compared with former smokers and nonsmokers. We identified 181 sirolimus-eluting stents in 140 subjects who underwent follow-up optical coherence tomography imaging. Subjects were divided into 3 groups: current smokers (n = 28), former smokers (n = 35), and nonsmokers (n = 77). Stent strut coverage, neointimal characteristics, and strut malapposition were evaluated. The incidence of uncovered stent struts was significantly higher in nonsmokers compared with current smokers (13.3 ± 13.3% vs 6.7 ± 8.3%; p = 0.001). On qualitative evaluation of neointimal morphology, the prevalence of heterogeneous neointima was higher in current smokers (71.9%) than in former smokers (36.0%) or nonsmokers (10.1%) (p = 0.004 and p <0.001, respectively). There was no difference in the incidence of malapposition among the 3 groups. Multivariate modeling showed that current smoking was negatively associated with the presence of uncovered struts (odds ratio 0.33; 95% confidence interval 0.14 to 0.79; p = 0.013) and positively associated with the presence of heterogeneous neointima (odds ratio 9.47; 95% confidence interval 3.79 to 23.72; p <0.001). In conclusion, the incidence of strut coverage was higher in current smokers compared with nonsmokers. However, the pattern of neointima was more heterogeneous in current smokers.

Clinical and pathological characteristics of homogeneous and nonhomogeneous tissue of in-stent restenosis visualized by optical coherence tomography

BACKGROUND

Although it is known that in-stent restenosis (ISR) patterns appear homogeneous or nonhomogeneous by optical coherence tomography (OCT), interpretations of the ISR inflammatory response, of the OCT image, and its pathological implications are unclear. The aim of this study was to use OCT to characterize ISR and its inflammatory index in patients after coronary stenting.

METHODS

OCT was performed at follow-up in 100 angiographic ISR lesions. ISR lesions were divided into two groups: (a) homogeneous (n=48) and (b) nonhomogeneous (n=52) image groups. We assessed the ISR images produced by OCT for tissue heterogeneity and neo-intimal hyperplasia using the normalized standard deviation of OCT signal-intensity (OCT-NSD) observed in neo-intimal hyperplasia tissue. In some patients with a nonhomogeneous OCT image, we collected pathological tissue.

RESULTS

The prevalence of drug-eluting stents was 48% in the nonhomogeneous group and 29% in the homogeneous group (P=0.05). The OCT-NSD value in the nonhomogeneous group (0.223±0.019) was significantly higher than that in the homogeneous group (0.203±0.025; P<0.0001). Pathological tissue showed fibrin thrombi with infiltrating macrophage in 12 cases of nonhomogeneous ISR. The area under the receiver operating characteristic curve for the prediction of a nonhomogeneous image was 0.73 for OCT-NSD (95% confidence interval: 0.62-0.83: P<0.0001). The odds ratio for the prediction of a nonhomogeneous image was 3.47 (95% confidence interval: 1.18-10.2: P=0.02) for smoking by logistic regression analysis.

CONCLUSION

Nonhomogeneous ISR visualized by OCT showed a high OCT-NSD value, which was a useful predictor for nonhomogeneous images. Moreover, the nonhomogeneous ISR image visualized by OCT may show chronic inflammation and fibrin thrombi.