Predictors for Neoatherosclerosis

Elevated Levels of Very Low-density Lipoprotein Cholesterol Independently Associated with In-stent Restenosis in Diabetic Patients after Drug-eluting Stent Implantation

Background:

High rate of in-stent restenosis (ISR) remained an unsolved clinical problem in clinical practice, especially among patients with diabetes mellitus (DM). Diabetic patients often had hypertriglyceridemia with elevated levels of very low-density lipoprotein cholesterol (VLDL-C). Increasing evidence suggested that VLDL-C was known as a significant risk factor for atherosclerosis and had been recommended as a treatment target by current dyslipidemia guidelines. However, the role of VLDL-C in the occurrence and development of ISR in coronary artery disease (CAD) patients with DM had not been studied. The aim of this study was to evaluate the association between the elevated levels of VLDL-C and the risk of ISR in CAD patients with DM.

Methods:

A total of 1390 diabetic patients, who underwent coronary drug-eluting stent (DES) implantation at Beijing Anzhen Hospital and followed up by angiography within 6–24 months, were consecutively enrolled. Patients’ demographic and clinical characteristics, including age, gender, CAD risk factors, family history, life style, medical history, and coronary angiographic information, were collected carefully at baseline percutaneous coronary intervention and follow-up angiography. Multivariate Cox's proportional hazards regression modeling using the step-wise method (entry, 0.05; removal, 0.05) was used to determine the independent risk associated with ISR in diabetic patients.

Results:

Finally, 1206 of patients were included in this study. ISR occurred in 132/1206 diabetic patients (10.9%) by follow-up angiography. Patients with ISR had elevated median serum VLDL-C levels compared with those without ISR (0.65 mmol/L vs. 0.52 mmol/L, P = 0.030). The multivariate regression analysis showed that VLDL-C was significantly associated with the risk of ISR in diabetic CAD patients (hazard ratio [HR] = 1.15, 95% confidence interval [CI]: 1.03–1.29, P = 0.017). The HR for the risk of ISR associated with VLDL-C level ≥0.52 mmol/L was 3.01 (95% CI: 1.24–7.34, P = 0.015).

Conclusion:

The elevated level of serum VLDL-C was a significant and independent risk factor for ISR in diabetic CAD patients after coronary DES implantation.

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.

Relationship between optical coherence tomography-defined in-stent neoatherosclerosis and out-stent arterial remodeling assessed by serial intravascular ultrasound examinations in late and very late drug-eluting stent failure

BACKGROUND

Little is known regarding the association between chronological out-stent vessel remodeling and in-stent tissue characteristics of drug-eluting stent (DES) failure. We aimed to evaluate the relationship between serial vessel remodeling after DES implantation and neoatherosclerosis (NA) assessed by optical coherence tomography (OCT) in patients with DES failure.

METHODS

Forty-eight patients with late and very late stent failure after DES implantation, who underwent intravascular ultrasound (IVUS) at both the initial percutaneous coronary intervention and the time of stent failure and OCT imaging at the time of stent failure, were retrospectively investigated. NA on OCT was defined as neointimal formation with the presence of lipids or calcification inside the stents. Lesions were divided into two groups: those with NA and those without NA (NA: n=21; non-NA: n=27). From the serial IVUS examinations, external elastic membrane (EEM) volume and out-stent plaque volume were normalized by stent length and their changes were compared between the two groups.

RESULTS

The NA group showed older stent age [median, 5.1 years (IQR, 4.8-8.3) vs 1.4 years (IQR, 0.8-4.5); p<0.01] and more prevalent sirolimus-eluting stents (SES; 81.0% vs. 29.6%; p<0.01). IVUS findings of the NA group showed a greater serial increase in both normalized EEM volume and normalized out-stent plaque volume (OSPVI) [1.05 (0.41-1.90) vs. 0.11 (-0.64 to 0.80) mm²; p<0.01; and 0.88 (0.57-1.98) vs. 0.12 (-0.41 to 0.78) mm²; p<0.01]. On multivariate analysis, percentage change in OSPVI (OR, 1.07; 95% CI, 1.01-1.14; p=0.02) and SES (OR, 9.78; 95% CI, 2.20-43.40; p<0.01) remained independent predictors of NA.

CONCLUSIONS

NA in late and very late DES failure was associated with out-stent positive vessel remodeling. In addition to SES, out-stent progressive positive remodeling may help predict NA in late and very late DES failure.

Impact of lesion complexity on long-term vascular response to cobalt-chromium everolimus-eluting stent: five-year follow-up optical coherence tomography study

The impact of lesion complexity on long-term vascular response to cobalt-chromium everolimus-eluting stent (CoCrEES) remains unclear. We sought to evaluate them using optical coherence tomography (OCT). A total of 47 patients with 58 lesions treated only with CoCrEES and no target-vessel events within 5 years after implantation were prospectively enrolled and underwent 5-year follow-up OCT. Quantitative parameters and qualitative characteristics of the neointima were evaluated using multilevel logistic or linear regression models with random effects at three levels: lesion, cross-section (CS), and strut. According to the lesion complexity, the lesions were classified into the two groups: the complex lesion (CL) and non-CL group. The CL was defined as having at least 1 high-risk feature such as acute coronary syndrome lesion, lesion length > 20 mm, severe calcification requiring rotational atherectomy, and chronic total occlusion at the index procedure. A total of 11,034 struts (CL, n = 6240; non-CL, n = 4794) and 1202 (CL, n = 683; non-CL, n = 519) CSs were analyzed. The percentage of uncovered and malapposed struts did not differ significantly between the CL and non-CL groups (0.90 vs. 0.54%, P = 0.78; 0.56 vs. 0.10%, P = 0.16, respectively). The incidence of neoatherosclerosis was comparable between both groups in the CS- and lesion-level analysis (3.5 vs. 4.6%, P = 0.91; 32.0 vs. 24.2%, P = 0.52, respectively). At 5 years, CoCrEES shows an excellent vascular healing and similar frequency of neoatheroslerosis in patients without target-vessel events, regardless of the lesion complexity.

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.

Dynamic neointimal pattern after drug-eluting stent implantation defined by optical coherence tomography

OBJECTIVES

Certain neointimal patterns including neoatherosclerosis (NA) are known to be associated with poor clinical outcome. The prevalence and time course of different neointimal patterns have not been studied systematically. The aim of this study was to investigate the serial changes in neointimal pattern after drug-eluting stent implantation.

PATIENTS AND METHODS

A total of 132 patients with 207 drug-eluting stents, who underwent two follow-up optical coherence tomography studies at 6 and 12 months, were included. Neointimal patterns were categorized as homogeneous, heterogeneous, layered, or NA using optical coherence tomography. Quantitative and qualitative analyses of neointima were carried out.

RESULTS

Both at 6 and at 12 months, the homogenous neointima was the predominant type (>75%), followed by the layered and the heterogeneous pattern. At 12 months, progression to NA was observed in 0.6% of the patients in the homogeneous group, in 5.6% of the patients in the heterogeneous group, and in 3.9% of the patients in the layered group. Regression to the homogeneous pattern was observed in 5.6% of the patients in the heterogeneous group and 11.5% of the patients in the layered group.

CONCLUSION

The homogenous neointima is the predominant pattern both at 6 and at 12 months. The neointimal pattern changed between 6 and 12 months in 10.6% of stents. Further studies are needed to understand the mechanisms of these neointimal changes and their clinical significance.

Clinical Implication of Optical Coherence Tomography-Based Neoatherosclerosis

Recent research has indicated neoatherosclerosis (NA), the de novo development of atherosclerosis within the neointimal region of the stented segment after coronary stent implantation, as a mechanism of late/very late stent thrombosis (VLST) and restenosis. This research is based on histologic and intravascular imaging studies. Optical coherence tomography (OCT) is an imaging tool that is superior with regard to resolution capacity, and can be used to visualize detailed information about distinct morphological characteristics of the restenotic tissue. Thus, OCT is a valuable imaging tool for examining NA, such as macrophage infiltration, lipid accumulation, in-stent calcification, or neointimal rupture. This article discusses the prevalence, predictors, and clinical implications of NA that can be observed by OCT.

In-stent neoatherosclerosis and tissue characteristics of restenotic lesions following implantation of second generation drug-eluting stents in unrestricted coronary lesions: Optical frequency domain imaging study

BACKGROUND

Differences in stent platform, polymer coatings, and antirestenotic drugs among the current in use second-generation drug-eluting stents (G2-DESs) may induce significant variations in neointimal response and vascular healing, which may impact the prevalence of neoatherosclerosis (NA) and morphological appearance of the restenotic tissue.

METHODS AND RESULTS

Utilizing Optical frequency domain imaging, two independent reviewers, retrospectively compared the prevalence of neoatherosclerosis (NA), and the morphological differences, and tissue characteristics of 50 G2-DESs in-stent restenosis (ISR) lesions (35 everolimus-eluting stent [22 cobalt-chromium (CoCr), 13 platinum-chromium (PtCr)], and 15 biolimus-eluting stent [BES]) implanted liberally in unrestricted coronary lesions. More than half of the stents were implanted in type C lesions, while 40% of the stents were implanted primarily in lesions with recanalized chronic total occlusion. NA, defined as a neointima formation with the presence of lipids or calcification, was observed in fewer than half (24/50) of all ISR lesions with no significant in-between group differences (41%, 69%, and 40% in CoCr, PtCr, and BES respectively, P = 0.22), nor were there any significant differences in the morphological appearance or tissue characteristics between all G2-DESs subtypes.

CONCLUSIONS

Acknowledging some limitations, our results may suggest that the prevalence of NA and the morphological appearance of restenotic lesions might not differ when G2-DESs are implanted in unrestricted, rather complex, coronary lesions.

A case of in-stent restenosis with pathologically proven chronic inflammation seven years after sirolimus-eluting stent implantation

A 67-year-old man was admitted to our hospital due to chest pain at rest. Seven years previously, the patient underwent percutaneous coronary intervention (PCI) of the left ascending artery and implanted sirolimus-eluting stent (SES). Coronary angioscopy (CAS) performed at that time showed a white plaque at the SES site. Two years after the first PCI, repeat CAS demonstrated light yellow plaques at the SES site. At the time of his presentation to our hospital, coronary angiography showed in-stent restenosis at the SES site, and CAS demonstrated the plaque rupture with presence of dense yellow plaque and various thrombi. After distal protection, drug-eluting balloon treatment was performed. Collected specimens from culprit sites included foamy macrophages, cholesterin crystals, neutrophils, and fibrin, suggesting that progressive neoatherosclerosis at the SES site triggered the acute coronary syndrome. This study highlights the importance of ensuring careful patient follow-up after SES implantation. <Learning objective: After 1st generation drug-eluting stent implantation, careful follow up is warranted, as the process of neoatherosclerosis can be ongoing and contribute to in-stent restenosis.>.

Management and Outcome of Patients With Acute Coronary Syndrome Caused by Plaque Rupture Versus Plaque Erosion: An Intravascular Optical Coherence Tomography Study

Background

Plaque rupture and erosion are the 2 most common mechanisms for acute coronary syndromes. However, the outcome of these 2 distinct pathologies in patients with acute coronary syndromes has never been studied.

Methods and Results

We retrospectively studied 141 patients with acute coronary syndromes who underwent optical coherence tomography (OCT) imaging of the culprit lesion prior to stenting from the Massachusetts General Hospital OCT Registry. Management (stent versus no stent), poststent OCT findings, and outcomes were compared. Among the 141 culprit lesions, rupture was found in 79 (56%) patients and erosion in 62 (44%). Stent implantation was performed in 77 (97.5%) patients with rupture versus 49 (79.0%) in those with erosion (P<0.001). Immediately after percutaneous coronary intervention, OCT showed a higher incidence of malapposition (37.5% versus 7.3%, P<0.001), thrombus (59.4% versus 14.6%, P<0.001), and protrusion (93.8% versus 73.2%, P=0.008) in the rupture group compared with the erosion group. Plaque rupture was associated with a higher incidence of no reflow or slow flow and distal embolization. Although cardiac event rates were comparable between the two groups at the 1‐year follow‐up, none of the erosion patients who were treated conservatively without stenting had adverse cardiac events.

Conclusions

Unfavorable poststent OCT findings were more frequent in rupture patients compared with erosion patients. A subset of erosion patients who were treated conservatively without stenting remained free of adverse cardiac events for up to 1 year.

Restenosis After Everolimus-eluting Vascular Scaffolding. Angiographic and Optical Coherence Tomography Characterization

INTRODUCTION AND OBJECTIVES

Coronary restenosis after bioresorbable vascular scaffold (BVS) implantation is infrequent and little information is available on the main characteristics of these lesions. The aim of this study was to assess restenotic lesions by using optical coherence tomography (OCT).

METHODS

We studied 330 patients with coronary artery disease who received 398 BVS to treat 380 lesions. These patients were clinically and angiographically evaluated at follow-up and OCT was carried out on detection of restenosis.

RESULTS

After a follow-up of 19 ± 10 months, 18 restenotic lesions were detected in 17 patients (5.4%). Depending on the time of presentation, most cases of restenosis were late or very late (9 ± 4 months). The most frequent angiographic pattern was focal restenosis in 12 (67%) patients, which was mainly located at the proximal border in 9 (75%) whether involving the scaffold or not. The homogeneous pattern was infrequent, occurring in 3 (25%) lesions and was only visualized in 3 out of 6 cases of restenosis located at the margin. When the focal restenosis was located in the platform, OCT showed a heterogeneous or layered pattern. Finally, diffuse restenosis was observed in 6 patients (33%). In diffuse restenosis, OCT revealed a lipid-laden or layered tissue structure and the presence of microvessels or microcalcification, potentially suggesting a neoatherosclerotic process.

CONCLUSIONS

After a mean follow-up of 19 months, the restenosis rate was 5.4%. Most restenotic lesions were focal, located at the proximal border. Diffuse restenosis mostly occurred late or very late and most showed signs suggestive of neoatherosclerosis.

The impact of in-stent neoatherosclerosis on long-term clinical outcomes: an observational study from the Kobe University Hospital optical coherence tomography registry

AIMS

Although pathological studies have indicated the development of neoatherosclerosis (NA) after stenting, its risk factors and impact on future clinical events remain unclear. We aimed to clarify the possible risk factors for NA development and to evaluate the impact of NA in a large Japanese observational OCT database of patients with coronary heart disease.

METHODS AND RESULTS

One hundred and seventy-five consecutive patients (314 lesions) who underwent OCT examination >1 year after bare metal or drug-eluting stent implantation were enrolled. We assessed the presence of NA by follow-up OCT and compared adverse clinical events between NA+ and NA- patients. Forty-six patients had NA at the follow-up OCT. These patients had higher low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP) levels at follow-up. In multivariate logistic analysis, LDL cholesterol and CRP levels at follow-up were independently associated with the presence of NA (odds ratio [OR]: 1.022, p=0.008, OR 1.022, p=0.001, respectively). Moreover, patients with NA had a higher incidence of major adverse cardiac events (MACE) at follow-up. Multivariate Cox hazard analysis showed that the presence of NA was an independent risk factor for MACE (hazard ratio: 2.909, p=0.012).

CONCLUSIONS

High LDL cholesterol and CRP levels may be risk factors for NA development in patients treated with coronary stents. Moreover, the presence of NA was independently associated with MACE, suggesting the need for careful clinical follow-up of these patients.

Localization of in-stent neoatherosclerosis in relation to curvatures and bifurcations after stenting

BACKGROUND

In-stent neoatherosclerosis (ISNA) is a final common pathway of late-stent failure. However, distribution of ISNA has been little reported. This study was to evaluate the localization of ISNA in relation to curvatures and bifurcations after stent implantation using optical coherence tomography (OCT).

METHODS

We retrospectively selected patients who underwent OCT examination ≥12 months after stent (sirolimus-eluting stents, SES) implantation. A stent curvature was defined if the angulation of the stent segment was >29°. Distribution of ISNA in relation to stent curvature and bifurcation was evaluated.

RESULTS

Totally, 331 patients were enrolled. The mean follow-up time was 15 months. Forty-one (12.3%) patients were found with ISNA. OCT results showed that stents with ISNA had thicker neointima (mean neointima thickness: 0.16 vs. 0.08 mm, P<0.001) compared to patients without ISNA. Segments with angulation >29° had a higher prevalence of ISNA compared with to angulation ≤29° [18 (18.4%) vs. 23 (9.9%), P=0.032]. ISNA was more frequently located at the "inner curvature" than the "outer curvature" (77.8% vs. 22.2%, P=0.018). If ISNA occurred in a branch, it was more often on the opposite side of the branch compared with the same side of the branch [21 (77.8%) vs. 6 (22.2%), P=0.004].

CONCLUSIONS

Localization of ISNA is related to vessel curvatures and bifurcations. ISNA occurs more often on the inner curvature and the opposite side of the branch.

Neoatherosclerosis after Drug-Eluting Stent Implantation: Roles and Mechanisms

In-stent neoatherosclerosis (NA), characterized by a relatively thin fibrous cap and large volume of yellow-lipid accumulation after drug-eluting stents (DES) implantation, has attracted much attention owing to its close relationship with late complications, such as revascularization and late stent thrombosis (ST). Accumulating evidence has demonstrated that more than one-third of patients with first-generation DES present with NA. Even in the advent of second-generation DES, NA still occurs. It is indicated that endothelial dysfunction induced by DES plays a critical role in neoatherosclerotic development. Upregulation of reactive oxygen species (ROS) induced by DES implantation significantly affects endothelial cells healing and functioning, therefore rendering NA formation. In light of the role of ROS in suppression of endothelial healing, combining antioxidant therapies with stenting technology may facilitate reestablishing a functioning endothelium to improve clinical outcome for patients with stenting.

Understanding and managing in-stent restenosis: a review of clinical data, from pathogenesis to treatment

The lumen diameter reduction after percutaneous coronary intervention (PCI) is well known as "restenosis". This phenomenon is due to vessel remodeling/recoil in case of no-stent strategy or, in case of stent employ, "neointimal proliferation" that consists in an excessive tissue proliferation in the luminal surface of the stent otherwise by a further new-occurring atherosclerotic process called "neoatherosclerosis". The exact incidence of in-stent restenosis (ISR) is not easy to determine caused by different clinical, angiographic and operative factors. In the pre-stent era the occurrence of restenosis ranged between 32-55% of all angioplasties, and drop to successively 17-41% in the bare metal stents (BMS) era. The advent of drug-eluting stent (DES), especially 2nd generation, and drug-coated balloon (DCB) further reduce restenosis rate until <10%. We here review the main characteristics of this common complication of coronary interventions, from its pathogenesis to the most appropriate treatment strategy.

Effects of Methotrexate in a Rabbit Model of In-Stent Neoatherosclerosis: An Optical Coherence Tomography Study

This study used optical coherence tomography (OCT) to investigate the effects of systemic methotrexate, in combination with a drug-eluting stent, on in-stent neoatherosclerosis in a rabbit model. Sirolimus-eluting stents were surgically implanted in the right common carotid arteries of 200 male New Zealand White rabbits; the animals received a high-fat diet, beginning one week before stent implantation. Each animal was randomly assigned to 1 of 4 groups, receiving intravenous injections of either methotrexate (0.4 mg/kg) or placebo weekly for 4 or 12 weeks. Stented arterial segments were harvested after stenting for 4 or 12 weeks, and processed for OCT and histological analysis. Prior to harvesting the arterial segments, blood was collected for the determinations of cytokine levels. Compared with the control animals, the methotrexate-treated animals showed lower rates of lipid-rich intima and per-strut low-signal intensity layers, smaller neointimal areas, and reduced neointimal thickness; larger fibrous cap thicknesses and smaller lumen areas were also seen in the animals receiving methotrexate. The levels of serum interleukin, adhesion molecules, and nuclear factor-κB p65 decreased and IL-10 level increased in the methotrexate-treated animals. Targeting the pro-inflammatory pathways may be an effective way to prevent restenosis without the long-term risk of late thrombosis.

Optical coherence tomography to evaluate coronary stent implantation and complications

Coronary optical coherence tomography (OCT) is now an established imaging technique in many catheterization laboratories worldwide. With its near-histological view of the vessel wall and lumen interface, it offers unprecedented imaging quality to improve our understanding of the pathophysiology of atherosclerosis, plaque vulnerability, and vascular biology. Not only is OCT used to accurately detect atherosclerotic plaque and optimize stent position, but it can further characterize plaque composition, quantify stent apposition, and assess stent tissue coverage. Given that its resolution of 15 μm is well above that of angiography and intravascular ultrasound, OCT has become the invasive imaging method of choice to examine the interaction between stents and the vessel wall. This review focuses on the application of OCT to examine coronary stents, the mechanisms of stent complications, and future directions of OCT-guided intervention.

Three-Year Clinical and Angiographic Outcomes After Everolimus-Eluting Stent Implantation in Patients With a History of Coronary Artery Bypass Grafting

The clinical and angiographic outcomes after percutaneous coronary intervention (PCI) with everolimus-eluting stent (EES) implantation in patients with a history of coronary artery bypass grafting (CABG) have yet to be fully investigated. The aim of the present study was to investigate 3-year clinical outcomes after EES implantation in patients with a history of CABG.We retrospectively enrolled 176 consecutive patients who had undergone EES implantation. Three-year clinical follow-up data were obtained from all patients. Follow-up angiograms and serial quantitative coronary angiography analysis (QCA) were performed for 139 (79.0%) patients. Patients from the prior CABG (+) group (n = 17; 9.7%) had higher incidences of target lesion revascularization (TLR; 41.2% versus 3.8%, P < 0.001) and major adverse cardiac events (47.1% versus 15.1%, P = 0.004). A landmark analysis conducted 1 year into our study showed a higher incidence of TLR in the prior CABG (+) group (20.0% versus 3.0%, P = 0.017).The reason for EES implantation in the prior CABG (+) group was saphenous vein graft (SVG) failure in 19 (79.2%) lesions, although the target vessel was the SVG in 8 (33.3%) lesions. There were no significant differences in clinical and follow-up QCA data between the native vessel and SVG PCI groups.This study revealed that a history of CABG was a risk factor for TLR after EES implantation. The major reason for PCI after CABG was SVG failure; both native vessel and SVG PCI showed poor outcomes. Further investigations may be warranted to determine which interventions are most effective in this high-risk subset.

Impact of Age on Stent Strut Coverage and Neointimal Remodeling as Assessed by Optical Coherence Tomography

While older age associates with adverse percutaneous coronary intervention (PCI) outcomes, detailed information relating age to stent strut coverage and neointimal characteristics is lacking. One hundred nineteen patients with 123 sirolimus-eluting stents (SESs) were divided into 3 groups: group A (≤55 years), group B (56-65 years), and group C (>65 years). At 6 and 12 months of follow-up, optical coherence tomography was performed to assess strut coverage and neointimal remodeling. At 6 months, the proportion of uncovered struts increased with age: 6.1% in group A versus 7.3% in group B versus 11.7% in group C (P < 0.001) while the proportion of embedded struts decreased: 72.1% versus 57.0% vs. 55.0%, respectively (P < 0.001). Mean neointimal thicknesses were 90  μm versus 60  μm versus 60  μm, respectively (P < 0.001), and neointimal areas were 0.82  mm2 versus 0.52  mm2 versus 0.57  mm2 (P < 0.001). At 12 months, the proportion of uncovered struts increased with age (3.9% vs. 3.3% vs. 4.9 %; P < 0.001), while mean neointimal thicknesses were 100 versus 70 versus 80  μm (P < 0.001) and neointimal areas were 0.87 versus 0.60 versus 0.67  mm2 (P < 0.001). Patients ≤55 years receiving SES showed highest strut coverage and neointimal repair rate compared with the other 2 groups. A "catch-up phenomenon" appeared to occur in the oldest patients, as in the first 6 months the neointima showed lowest endothelial cell coverage and lowest neointimal proliferation rate, whereas from 6 to 12 months, the highest neointimal proliferation rate was seen in the oldest patients.

The clinical characteristics and prognosis of lesions with in-stent eccentric tissue proliferation and strong signal attenuation detected by optical coherence tomography

There are still some patients who require repeat revascularization despite of drug-eluting stent (DES) implantation. The present study aimed to investigate the relationship between optical coherence tomography (OCT) findings and recurring target lesion revascularization (TLR) after percutaneous coronary intervention (PCI) for in-stent restenosis (ISR). We reviewed 50 patients (54 coronary lesions) who underwent PCI for ISR, which included 25 DES-ISR lesions. The PCI strategy depended on the interventionalist's discretion, and DES implantation was performed for 38 (70 %) lesions. Tissue characteristics were assessed qualitatively and quantitatively using the frame showing maximal lumen narrowing (minimal lumen area). In qualitative analysis, OCT detected coexistence of eccentric tissue proliferation and strong signal attenuation (ESA). ESA was observed in six lesions (11 %) in five patients (10 %). Hemodialysis (80 vs. 20 %, p = 0.013) and DES-ISR (100 vs. 40 %, p = 0.0069) were significantly more frequent in ESA patients/lesions than in others. One-year follow-up revealed that re-TLR was more frequently performed for ESA lesions (83 vs. 8 %, p = 0.0002). The findings reveal that ESA detected in OCT images of ISR is related to TLR after PCI for DES-ISR especially in patients undergoing maintenance hemodialysis.

Stent thrombosis and restenosis: what have we learned and where are we going? The Andreas Grüntzig Lecture ESC 2014

Modern-day stenting procedures leverage advances in pharmacotherapy and device innovation. Patients treated with contemporary antiplatelet agents, peri-procedural antithrombin therapy and new-generation drug-eluting stents (DES) have excellent outcomes over the short to medium term. Indeed, coupled with the reducing costs of these devices in most countries there remain very few indications where patients should be denied treatment with standard-of-care DES therapy. The two major causes of stent failure are stent thrombosis (ST) and in-stent restenosis (ISR). The incidence of both has reduced considerably in recent years. Current clinical registries and randomized trials with broad inclusion criteria show rates of ST at or <1% after 1 year and ∼0.2-0.4% per year thereafter; rates of clinical ISR are 5% respectively. Angiographic surveillance studies in large cohorts show rates of angiographic ISR of ∼10% with new-generation DES. The advent of high-resolution intracoronary imaging has shown that in many cases of late stent failure neoatherosclerotic change within the stented segment represents a final common pathway for both thrombotic and restenotic events. In future, a better understanding of the pathogenesis of this process may translate into improved late outcomes. Moreover, the predominance of non-stent-related disease as a cause of subsequent myocardial infarction during follow-up highlights the importance of lifestyle and pharmacological interventions targeted at modification of the underlying disease process. Finally, although recent developments focus on strategies which circumvent the need for chronically indwelling stents--such as drug-coated balloons or fully bioresorbable stents-more data are needed before the wider use of these therapies can be advocated.

Optical coherence tomographic observation of in-stent neoatherosclerosis in lesions with more than 50% neointimal area stenosis after second-generation drug-eluting stent implantation

BACKGROUND

Despite the enhanced properties of the second-generation drug-eluting stent (DES), its association with neoatherosclerosis has not been sufficiently evaluated. Therefore, we sought to evaluate and compare neoatherosclerosis in second-generation DESs to first-generation DESs.

METHODS AND RESULTS

A total of 212 DES-treated patients with >50% percent neointimal cross-sectional area stenosis were retrospectively enrolled from the Korean multicenter optical coherence tomography (OCT) registry. Within this population, 111 patients had a second-generation DES (40 zotarolimus, 36 everolimus, and 35 biolimus) and 101 patients had a first-generation (65 sirolimus and 36 paclitaxel) DES. Neoatherosclerosis on OCT was defined as neointima formation with the presence of lipids or calcification. OCT-determined neoatherosclerosis was identified in 27.4% (58/212) of all DES-treated lesions. The frequency of neoatherosclerosis increased with the stent age. Stent age was shorter in the second-generation DES group (12.4 months versus 55.4 months, P<0.001), and neoatherosclerosis was less frequently observed in that group (10.8% versus 45.5%, P<0.001). However, after adjusting for cardiovascular risk factors, chronic kidney disease (odds ratio, 4.113; 95% confidence interval, 1.086-15.575; P=0.037), >70 mg/dL of low-density cholesterol at follow-up OCT (odds ratio, 2.532; 95% confidence interval, 1.054-6.084; P=0.038), and stent age (odds ratio, 1.710; 95% confidence interval, 1.403-2.084; P<0.001) were all independent predictors for neoatherosclerosis, whereas the type of DES (first- versus second-generation) was not. Patients with neoatherosclerosis showed a higher rate of acute coronary syndrome at follow-up OCT (19.0% versus 3.9%, respectively, P=0.001).

CONCLUSIONS

The second-generation DES is not more protective against neoatherosclerosis compared with the first-generation DES.

OCT demonstrating neoatherosclerosis as part of the continuous process of coronary artery disease

Although the advent of drug-eluting stents has reduced the rates of target vessel revascularization, there are observations of ongoing stent failure occurring very late after stent implantation and presenting as very late restenosis or as very late stent thrombosis. The de novo development of atherosclerosis within the neointimal region, called neoatherosclerosis, has been identified as one of the pathomechanisms of these observed late stent failures. The mechanisms of neoatherosclerosis development and its association with stent failure are currently the subject of intensive research. Optical coherence tomography (OCT) is an invasive imaging modality that allows us to visualize the micromorphology of coronary arteries with near-histological resolution, thus providing detailed assessment of the morphological characteristics of the neointima after stent implantation, including neoatherosclerosis. Several OCT studies have tried to provide in vivo insights in the mechanisms of neoatherosclerosis development and its association with late stent failure. This review summarizes the current insights into neoatherosclerosis obtained with OCT and discusses the association of neoatherosclerosis with late stent failure.

Incidence, clinical presentation, and predictors of early neoatherosclerosis after drug-eluting stent implantation

BACKGROUND

Compared with bare-metal stents, neoatherosclerosis reportedly develops earlier and more frequently after drug-eluting stent (DES) implantation. This study evaluated the incidence, clinical presentation, and predictors of early neoatherosclerosis after DES implantation.

METHODS

Neointimal characteristics were evaluated in 449 patients (482 lesions) who underwent follow-up optical coherence tomography ≤12 months after DES implantation (median 9.1 months) and displayed a mean neointimal thickness >100 μm. Neoatherosclerosis was defined as neointima with the presence of lipid or calcification.

RESULTS

Early neoatherosclerosis, defined as occurrence of neoatherosclerosis within 12 months after DES implantation, was observed in 31 lesions (6.4%). Compared with patients without early neoatherosclerosis, those with early neoatherosclerosis presented with a higher incidence of clinical symptoms (13% vs 57%, respectively; P < .001) and had undergone a higher frequency of target-lesion revascularization (9% vs 55%, respectively; P < .001) at the time of optical coherence tomography follow-up. Multivariate logistic regression analysis showed that independent predictors of early neoatherosclerosis were hypertension (odds ratio 3.20, 95% CI 1.32-7.78, P = .010) and pre-stent low-density lipoprotein cholesterol ≥130 mg/dL at the time of the index procedure (odds ratio 3.89, 95% CI, 1.62-9.36, P = .002).

CONCLUSIONS

Early neoatherosclerosis was detected in 6.4% of DES-treated lesions with neointimal thickness >100 μm at a median of 9.1 months after DES implantation. The occurrence of early neoatherosclerosis was significantly associated with presentation of clinical symptoms. Independent predictors of early neoatherosclerosis were hypertension and high pre-stent low-density lipoprotein cholesterol at the time of the index procedure.

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.