Heterogeneous Neointima Research Articles

Early thrombus formation is required for eccentric and heterogeneous neointimal hyperplasia under disturbed flow

BackgroundAnticoagulation and antiplatelet therapy effectively inhibit neointimal hyperplasia (NIH) in both arterial and venous systems but not in arteriovenous fistulae (AVF). The main site of AVF failure is the juxta-anastomotic area that is characterized by disturbed flow compared with laminar flow in the arterial inflow and the venous outflow. ObjectivesWe hypothesized that early thrombus formation is required for eccentric and heterogeneous NIH in the presence of disturbed flow. MethodsNeedle puncture and sutured AVF were created in C57BL/6 mice, in PF4-Cre × mT/mG reporter mice, and in Wistar rats. Human AVF samples were second-stage basilic vein transpositions. The tissues were examined by histology, immunofluorescence, immunohistochemistry, and en face staining. ResultsIn the presence of disturbed flow, both mouse and human AVF showed eccentric and heterogeneous NIH. Maladapted vein wall was characterized by eccentric and heterogeneous neointima that was composed of a different abundance of thrombus and smooth muscle cells. PF4-cre × mT/mG reporter mice AVF showed that green fluorescent protein-labeled platelets deposit on the wall directly facing the fistula exit with endothelial cell loss and continue to accumulate in the presence of disturbed flow. Neither disturbed flow with limited endothelial cell loss nor nondisturbed flow induced heterogeneous neointima in different animal models. ConclusionEarly thrombus contributes to late heterogeneous NIH in the presence of disturbed flow. Disturbed flow, large area of endothelial cell loss, and thrombus formation are critical to form eccentric and heterogeneous NIH. Categorization of adapted or maladapted walls may be helpful for therapy targeting heterogeneous NIH.

Morphological characteristics of in-stent restenosis with different degrees of area stenosis: an optical coherence tomography study.

The morphological characteristics of in-stent restenosis (ISR) in relation to varying degrees of area stenosis have not been comprehensively examined. This study aimed to explore the tissue characteristics of patients experiencing ISR with different degrees of area stenosis through the utilization of optical coherence tomography (OCT). In total, 230 patients with ISR who underwent OCT were divided into the following three groups: area stenosis (AS) < 70% (n = 26); 70-80% (n = 119) and AS ≥ 80% (n = 85). Among the 230 patients, the clinical presentation as stable angina was 61.5% in AS < 70%, followed by 47.2% in 70% < AS ≤ 80%, and 31.8% in AS ≥ 80% (P = 0.010). The OCT findings showed that heterogeneous neointima, ISNA, LRP, neointima rupture, TCFA-like pattern, macrophage infiltration, red and white thrombus was more common with AS increased. Ordinal logistic regression analysis showed that higher AS was associated with previous dyslipidemia (odds ratio [OR], 4.754; 95% confidence interval [CI], 1.419-15.927, P = 0.011), neointimal rupture (OR: 3.640; 95% CI, 1.169-11.325, P = 0.026), red thrombus (OR: 4.482; 95% CI, 1.269-15.816, P = 0.020) and white thrombus (OR: 5.259; 95% CI, 1.660-16.659, P = 0.005). Patients with higher degrees of area stenosis in the context of ISR exhibited a greater number of discernible morphological characteristics as identified through OCT analysis. Furthermore, previous dyslipidemia, neointimal rupture, white thrombus and red thrombus were highly associated with and the progression of ISR lesions.

Apport de la tomographie par cohérence optique dans la prise en charge de la resténose intrastent

Intrastent restenosis (ISR) remains a common problem in interventional cardiology. Angiographic data are limited in assessing ISR. Optical coherence tomography (OCT) is a high-resolution endocoronary imaging technique. It allows individualization of the stent struts and thus reveals stent under-expansion or fracture, which are sometimes difficult to demonstrate on angiography. Restenotic tissue is also identified and can be classified as homogeneous neointima, heterogeneous neointima or neoatherosclerosis. OCT therefore helps guide the treatment of ISR, which varies depending on the etiology. This imaging technique also allows us to verify that the criteria for successful angioplasty have been met and thus to correct a potential risk factor for recurrence of ISR. These remarks are illustrated by two clinical cases. OCT is now validated in this indication, it remains to validate the interest of the technique on the follow-up of the patients and to integrate the new tools at our disposal.

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

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. 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. 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). 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.

Impact of optical coherence tomography-derived neointimal tissue morphology on development of very late in-stent restenosis.

This study evaluated the progression of very late in-stent restenosis (VL-ISR) by analyzing four serial coronary angiography (CAG) images and its correlation with neointimal tissue characterization of the VL-ISR lesions on optical coherence tomography (OCT). Recently, VL-ISR is occasionally observed beyond a few years after drug-eluting stents (DESs) implantation. This study analyzed 50 VL-ISR lesions after DES in which 4 serial CAGs over a period of 2 years, including at baseline procedure, 9 months after baseline procedure, 12 months before VL-ISR, and at the time of VL-ISR, were performed. Neointimal tissue characteristics by OCT were categorized as homogeneous, heterogeneous with invisible strut (Type I), heterogeneous with visible strut (Type II), speckled (Type III), or heterogeneous with sharply delineated border (Type IV). From the development process, 23 VL-ISRs (46%) were categorized as rapid progression and 27 (54%) as gradual progression. The five categories of neointimal tissue composition significantly differed between lesions with rapid and gradual progression. Homogeneous neointima and Type IV heterogeneous neointima were observed only in lesions with gradual progression. Moreover, most Type I heterogeneous neointima was identified in lesions with gradual progression. Instead, main neointimal tissue components of lesions with rapid progression were Type II (43%) and Type III (43%) heterogeneous neointima. The progression rate of in-stent atherosclerotic changes is gradual, whereas organized thrombus could be associated with an increased risk of rapid neointimal growth. The two types of stenosis progression provide a new insight into the mechanism of VL-ISR development after DES implantation.

P197 Similarity and difference in in-stent neoatherosclerosis assessment between near-infrared spectroscopy and optical coherence tomography

Abstract Backgrounds Near-infrared spectroscopy (NIRS) has been implicated to assess the composition of the atherosclerotic plaques in native coronary arteries. However, little has been reported about the assessment of neoatherosclerosis within stents by NIRS. Optical coherence tomography (OCT) is one of the current clinical standard modalities to identify neoatherosclerosis. We sought to compare NIRS and OCT assessments in the detection and evaluation of in-stent neoatherosclerosis. Methods We retrospectively analyzed 54 in-stent lesions in 52 patients who underwent both NIRS and OCT examinations before percutaneous coronary intervention (PCI). All stented segment in both PCI target and non-target lesions were investigated. NIRS analysis included lipid core burden index (LCBI)4mm. NIRS-derived lipid-rich plaque (NIRS-lipid) is defined as LCBI4mm more than 400 according to the previous studies. OCT-derived lipid-laden neointima (OCT-lipid) was defined as having a signal-poor region with diffuse border precluding visualization of stent struts of more than 90 degrees and 1mm in longitudinal length. OCT analysis included the presence or absence of lipid-laden neointima, calcification, ruptured plaque, thrombus, heterogeneous neointima and measurement of lipid length and lipid arc. Lipid volume index (LVI) was defined by OCT as the averaged lipid arc multiplied by lipid length. Max LCBI4mm were compared in lesions with co-registered OCT findings and correlations between max LCBI4mm and LVI were determined. Additionally, OCT findings predicting max LCBI4mm more than 400 were determined. Results Max LCBI4mm was 202 (7.5-460). OCT-lipid was observed in 31 (57.4%) lesions. LVI was 1283 (475-4725). Lesions with OCT-lipid has significantly higher LCBI than those without OCT-lipid (343 [106-593] vs 42 [0-260], p = 0.003). On the other hand, max LCBI were not significantly different according to the presence or absence of calcification, ruptured plaque, thrombus and heterogeneous neointima (60 [39-537] vs 227 [6-451], p = 0.913; 441 [43-547] vs 202 [6-435], p = 0.328; 245 [10-548] vs 251 [42-446], p = 0.990; 202 [40-440] vs 235 [3-471], p = 0.970, respectively). Linear regression analysis showed significant correlation between LVI and max LCBI4mm (P &amp;lt; 0.001). Receiver operating characteristic (ROC) analysis showed the best cutoff max LCBI4mm value for predicting OCT-lipid was 148 (Area under the curve [AUC] = 0.735). ROC analysis showed the best cutoff lipid length and maximum lipid arch value for predicting LCBI4mm more than 400 was 1.9 mm and 128 degrees, (AUC = 0.741, 0.732, respectively) respectively. Conclusion There is good agreement between NIRS and OCT for detection of neoatherosclerosis in stented lesions. In the in-stent lesions, the cut-off value of max LCBI for predicting OCT-lipid was smaller than the previously reported value in de novo lesions. Application of different cut-off value may be considered in in-stent lesions.

Contribution of Poststent Irregular Protrusion to Subsequent In-Stent Neoatherosclerosis after the Second-Generation Drug-Eluting Stent Implantation.

Previous optical coherence tomography (OCT) study reported that irregular protrusion (IP) post drug-eluting stent (DES) implantation was an independent predictor of clinical outcome; however, the relationship between IP and the presence of subsequent in-stent neoatherosclerosis remains unclear. This study aimed to assess the relationship between IP and in-stent neoatheroscrerosis formation using OCT. We evaluated 83 patients (101 lesions) who underwent second-generation DES implantation and 8-month follow-up (8M-FU) using OCT. Lesions were divided into two groups in presence of IP (IP: n = 43, non-IP: n = 58). At prepercutaneous coronary intervention (pre-PCI), lipid-rich plaque, lesions with positive remodeling, and in-stent thrombus formation were more frequent in IP than in non-IP. On multivariate analysis, the thrombus at pre-PCI and the lesions with positive remodeling were independent predictors of IP. At 8M-FU, heterogeneous neointima, microvessel, lipid-laden neointima, and thin-cap fibro-atheroma like neointima were more frequent in IP than in non-IP (respectively, P < 0.05). On multivariate analysis, IP was associated with heterogeneous neointima. Binary restenosis was more frequent and late lumen loss tended to be larger in IP than in non-IP (19% versus 5%, P = 0.04; 1.25 ± 1.24 mm versus 0.91 ± 0.63 mm, P = 0.09); however, the target lesion revascularization rate was similar in both groups at 8M-FU. In conclusion, our study suggested that poststent IP was associated with subsequent neoatherosclerosis formation at 8M-FU after the second-generation DES implantation.

Incidence and Morphological Predictors of Intrastent Coronary Thrombus After Drug-Eluting Stent Implantation (from a Multicenter Registry)

The mechanisms responsible for late and very late stent thrombosis remain incompletely understood. This study aimed to evaluate the incidence and morphologic predictors of intrastent thrombus in patients after drug-eluting stent (DES) implantation using optical coherence tomography (OCT). A total of 208 patients with 262 DES who underwent follow-up OCT examination >6 months after DES implantation were included. The detailed vascular morphology including characteristics of neointima was analyzed. Thrombus was identified in 24 patients (11.5%) 11 months after DES implantation. Minimal lumen cross-sectional area was significantly smaller in the thrombus group than in the nonthrombus group (2.9 ± 1.7 vs 4.6 ± 2.0 mm(2); p <0.001). No difference was found in the frequency of uncovered or malapposed struts between the 2 groups. Thin-cap fibroatheroma (20.6% vs 0.1%; p <0.001) and heterogeneous neointima (22.2% vs 9.0%; p = 0.001) were more frequently detected in the thrombus group compared to the nonthrombus group. Second-generation DES showed lower incidence of thrombus, uncovered struts, and extrastent lumen compared with first-generation DES. In conclusion, the present OCT study revealed that smaller lumen cross-sectional area and neointimal morphology are important factors associated with intrastent thrombus. Second-generation DES demonstrated improved arterial healing and a lower incidence of intrastent thrombus compared with first-generation DES.

Abstract 11522: Does Neointimal Pattern Predict Instent Thrombus

Introduction: Local determinants of instent thrombus formation after drug-eluting stent (DES) implantation have not been systematically investigated. Hypothesis: Certain neointimal patterns assessed by optical coherence tomography (OCT) may represent local surface thrombogenesity after DES implantation. Methods: A total of 208 patients with 262 DES who underwent follow-up OCT examination 11 months after DES implantation were studied. The detailed OCT findings including characteristics of neointima, lumen size, and stent morphology were compared between the group with and without thrombus. Results: Thrombus was identified in 11.5% (24/208) of the patients. Lipid-laden neointima, thin-cap fibroatheroma, heterogeneous neointima, and extra-stent lumen were more frequently detected in the thrombus group compared to the non-thrombus group (Figure). No difference was found in the % of uncovered (4.9±6.7% vs. 4.2±5.4%; p=0.575) or malapposed struts (1.5±2.5% vs. 0.8±2.1%; p=0.116) between the two groups. Minimal lumen cross sectional area was significantly smaller in the thrombus group compared with the non-thrombus group (2.9±1.7mm 2 vs. 4.6±2.0mm 2 ; p&lt;0.001). Conclusions: Neointimal morphology and smaller lumen cross-section area are important factors associated with instent thrombus.

Optical coherence tomography study of chronic-phase vessel healing after implantation of bare metal and paclitaxel-eluting self-expanding nitinol stents in the superficial femoral artery

BackgroundThis study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT). MethodsTwenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated. ResultsThe mean neointimal thickness was significantly less with PTX stents (544.9±202.2μm vs. 865.0±230.6μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively). ConclusionAfter 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.

In-stent neointimal characteristics and late neointimal response after drug-eluting stent implantation: A preliminary observation

BackgroundProgressive neointimal proliferation may lead to late restenosis and/or neoatherosclerosis after drug-eluting stent (DES) implantation. Late neointimal response may be different among different tissue characteristics. The aim of this study was to assess impact of in-stent neointimal characteristics on late neointimal response following DES implantation. MethodsSerial (median 270 days and median 551 days after stent implantation) optical coherence tomography (OCT) examinations were performed in 42 stented lesions from 26 patients. In-stent neointimal tissue was categorized as either homogeneous or heterogeneous neointima based on the OCT appearance at 1st follow-up. Serial changes in neointimal area (NIA) were compared between lesions with homogeneous neointima and those with heterogeneous neointima. ResultsAt first follow-up, homogeneous neointima was observed in 22 (52%) and heterogeneous neointima in 20 (48%) lesions, respectively. During follow-up, NIA in lesions with homogeneous neointima decreased significantly (1.8±0.93mm2 to 1.5±0.88mm2, p<0.001). On the other hand, NIA in lesions with heterogeneous neointima did not change significantly (2.7±1.8mm2 to 2.8±1.6mm2, p=0.658). Homogeneous neointima was the only predictor of late neointimal regression (late neointimal regression defined as NIA at first follow-up – NIA at second follow-up <0) by multivariable analysis (odds ratio=7.591, 95% confidence interval: 1.616–35.67, p=0.010). ConclusionsOCT characteristics of neointima after DES implantation may be related to late neointimal progression or regression.

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.

Abstract 13746: Relationships between Neointimal Tissue Characteristics and Occurrence of Periprocedural Myocardial Infarction in Lesions with In-Stent Restenosis

Background: Recent studies have reported several types of neointimal tissues including neoatherosclerotic progression in stent restenosis. However, the influence of neointimal tissue characteristics on outcomes after percutaneous coronary intervention (PCI) for in-stent restenosis (ISR) remains unclear. Periprocedural myocardial infarction (PMI) is related to poor outcomes after PCI. We assessed relationships neointimal tissue characteristics and occurrence of PMI after PCI in ISR lesions. Methods: We investigated 45 ISR lesions in 45 stable angina pectoris (SAP) patients who underwent pre- and post-PCI coronary angioscopy (CAS) and optical coherence tomography (OCT) examination. We excluded patients with hemodialysis. All lesions were divided into lesions with PMI, defined as high-sensitivity cardiac troponin-T (hs-cTnT) values after PCI ≥5 times of the upper reference limit in patients with normal baseline values or ≥5 times of baseline values if hs-cTnT values were elevated before PCI, and those without. Clinical and lesion characteristics including intrastent neointimal tissues were compared between two groups. Results: PMI was observed in 15 (33.3%) lesions. Clinical characteristics including stent types and terms after stenting were similar between lesions with and without PMI. CAS analysis showed higher frequency of white neointimal proliferation with irregular surface or yellow neointima at the culprit site before PCI (86.7% vs. 43.3%, p=0.009) and atheromatous appearance (CAS-AP), defined as yellow plaque including complex thrombi underneath disrupted neointimal coverage after ballooning (66.7% vs. 16.7%, p=0.003) in lesions with PMI than those without. OCT analysis demonstrated higher frequency of heterogeneous neointima or neointimal thin-cap fibroatheroma in lesions with PMI (73.3% vs. 33.3%, p=0.02). Multivariate analysis including clinical and lesion characteristics and procedural results showed CAS-AP as an independent predictor for occurrence of PMI (odds ratio:6.90, 95% CI:1.68-28.41, p=0.008). Conclusions: In ISR lesions with SAP patients, the assessment of neointimal tissue characteristics by using CAS and OCT images may be useful for the prediction of occurrence of PMI.

Long-Term Outcomes of Neointimal Hyperplasia Without Neoatherosclerosis After Drug-Eluting Stent Implantation

ObjectivesThe aim of this study was to investigate the correlation between in-stent neointimal tissue without features of neoatherosclerosis and long-term clinical outcomes. BackgroundRecent studies have reported differential morphological characteristics of in-stent neointimal tissue assessed by optical coherence tomography (OCT). MethodsThe study population consisted of 336 patients with 368 drug-eluting stent-treated lesions. Patients received a follow-up OCT examination without any intervention. OCT-based neointima was categorized as homogeneous (n = 227 lesions in 208 patients), heterogeneous (n = 79 lesions in 73 patients), or layered (n = 62 lesions in 55 patients). Major adverse cardiac events (MACE) (a composite of cardiac death, nonfatal myocardial infarction, or target lesion revascularization) were assessed according to neointimal patterns during long-term clinical follow-up after OCT examination. ResultsThe time interval between stent implantation and OCT examination was similar among the 3 groups (p = 0.64). On multivariate logistic regression analysis, the significant determinant for the heterogeneous neointima was age (odds ratio [OR]: 1.037, 95% confidence interval [CI]: 1.007 to 1.068, p = 0.015) and an initial clinical presentation of acute coronary syndrome (OR: 1.967, 95% CI: 1.159 to 3.339, p = 0.012). The overall median follow-up duration for all patients after follow-up OCT examination was 31.0 months, and this was statistically different among the heterogeneous group (22.0 months), the homogeneous group (34.0 months), and the layered group (28.0 months, overall p = 0.002). MACE occurred more frequently in patients with heterogeneous neointima over a median 31-month follow-up period after OCT examination (13.7% vs. 2.9% in homogeneous vs. 7.3% in layered, p = 0.001). A propensity score–adjusted Cox regression analysis showed that independent risk factors for MACE were inclusion in the heterogeneous neointima (hazard ratio: 3.925, 95% CI: 1.445 to 10.662, p = 0.007) and minimal lumen cross-sectional area (hazard ratio: 0.368, 95% CI: 0.242 to 0.560, p < 0.001). ConclusionsDetermination of neointimal characteristics is helpful in predicting long-term clinical outcomes. Our data suggest that heterogeneous lesions are linked to poor long-term clinical prognoses.

Temporal course of neointimal hyperplasia following drug-eluting stent implantation: a serial follow-up optical coherence tomography analysis.

We sought to evaluate the temporal course of neointimal hyperplasia (NIH) after drug-eluting stent (DES) implantation, using serial optical coherence tomography (OCT). We identified 89 DES (82 patients) that had at least three consecutive cross-sections with a mean NIH thickness >100 µm on first follow-up OCT. Qualitative and quantitative changes in NIH were then assessed at a second follow-up OCT. NIH regression and progression were defined as a decrease or increase in mean NIH cross-sectional area >0.2 mm2, respectively, between the two studies. Between the first and second OCT there was a decrease in NIH in 29 lesions (32.6%), and an increase in NIH in 37 lesions (41.6%). Compared to patients with neointimal progression, those with regression showed lower levels of high sensitivity C-reactive protein (hsCRP) (p = 0.036) and higher levels of high-density lipoprotein (p = 0.012). Between the first and the second OCT, there were no significant changes in NIH morphologic patterns in 67 (75.3%) of 89 DES. In lesions with NIH regression, the evolution of heterogeneous to homogeneous neointima was observed, while the evolution of heterogeneous or homogeneous to layered neointima or the evolution of heterogeneous, homogeneous, or layered neointima to neoatherosclerosis was detected in lesions with NIH progression (p < 0.001). The hsCRP level at index procedure was significantly associated with neointimal regression in multivariate model (odds ratio 0.891, 95% confidence interval 0.796-0.999, p = 0.048). During late follow-up, OCT shows both NIH progression and regression that are paralleled by qualitative changes indicating increasing stability (in regression) and increasing instability (in progression).

Optical coherence tomographic observation of morphological features of neointimal tissue after drug-eluting stent implantation.

PurposeThe impacts of different time courses and the degree of neointimal growth on neointimal morphology have not yet been sufficiently investigated. Therefore, we evaluated the morphological features of neointimal tissue after drug-eluting stent (DES) implantation using optical coherence tomography (OCT).Materials and MethodsThe morphological features of neointimal tissue in stented segments with a maximal percentage of cross-sectional area (CSA) stenosis of neointima were evaluated in 507 DES-treated lesions with >100 µm mean neointimal thickness on follow-up OCT. Neointimal tissue was categorized as homogeneous, heterogeneous, layered, or neoatherosclerotic.ResultsIn lesions with <50% of neointimal CSA stenosis, homogeneous neointima (68.2%) was predominant, followed by heterogeneous neointima (14.1%) and layered neointima (14.1%). In lesions with ≥50% of neointimal CSA stenosis, layered neointima was most frequently observed (68.3%), followed by neoatherosclerotic neointima (25.2%). In subgroup analysis of lesions with ≥50% of neointimal CSA stenosis, 89.5% of the lesions with a stent age <30 months were layered neointima, while 62.3% of the lesions with a stent age ≥30 months were neoatherosclerotic neointima.ConclusionThis study suggests that the OCT-detected morphology of DES neointimal tissue was different according to the follow-up time course and degree of neointimal hyperplasia.

Difference in neointimal appearance between early and late restenosis after sirolimus-eluting stent implantation assessed by optical coherence tomography

Late in-stent restenosis (ISR) is an important clinical issue in the drug-eluting stent era. Autopsy studies have reported different underlying mechanisms between early ISR and late ISR. The aim of the present study was to compare the neointimal tissue appearance between early ISR (<1 year) and late ISR (>1 year) after sirolimus-eluting stent (SES) implantation using optical coherence tomography (OCT). We examined the neointimal tissue appearance in 48 ISR lesions after SES implantation [30 early ISR lesions (8±1 months after stenting) and 18 late ISR lesions (34±14 months after stenting)] by OCT. ISR was defined as percent diameter stenosis more than 50% within the stented segment in angiography. Lipid-rich neointima was characterized by signal-poor regions with diffuse borders. Thin-cap fibroatheroma (TCFA)-like neointima was defined by lipid-rich neointima with cap thickness 65 μm or less. In the OCT findings, heterogeneous neointima was more often observed in the late ISR group compared with the early ISR group (89 vs. 43%, P=0.002). Although the frequency of intraluminal thrombus was not different between the two groups (P=0.085), the frequency of lipid-rich neointima (83 vs. 27%, P<0.001), TCFA-like neointima (39 vs. 10%, P=0.028), microchannels within neointima (67 vs. 27%, P=0.007), and neointimal disruption (33 vs. 3%, P=0.008) was significantly higher in the late ISR group. In the present OCT study, it was found that atherosclerotic progression of neointima, such as lipid-rich neointima, TCFA-like neointima, microchannels, and neointimal disruption, was more often observed in late ISR lesions after SES implantation compared with early ISR ones.

Neointimal tissue characteristics following sirolimus-eluting stent implantation: OCT quantitative tissue property analysis

The neointimal tissue characteristics inside sirolimus-eluting stent (SES) were evaluated by optical coherence tomography (OCT) according to follow-up duration. One hundred and thirty-three Optical coherence tomography was performed in 96 patients with 143 SES which were retrospectively included and divided into 2 groups according to follow-up duration: Group 1, <24 months (98 stents in 71 patients); Group 2, >24 months (35 stents in 25 patients). The neointimal tissue coverage pattern and characteristics were studied using a new OCT analysis system which can quantitatively analyze tissue property by measuring attenuation, backscatter and signal intensity in the region of interest. Using these parameters, a multivariable logistic regression model was constructed to divide neointima into homogenous or heterogeneous type. We defined homogeneous nointima as neointimal tissue having uniform optical properties and does not showing focal variations in backscattering pattern and heterogeneous neointima as neointimal tissue with focally changing optical properties and showing various backscattering patterns. The average time between stent implantation and follow-up OCT imaging was 1.2 years in Group 1 and 3.2 years in Group 2. The number of neointima covered cross-sections, neointimal thickness, and neointimal area increased significantly with the length of follow-up duration after SES implantation (P < 0.01). The incidence of heterogeneous neointima was higher in Group 2 than in Group 1 (P < 0.01). Heterogeneous neointima was associated with higher incidence of microvessels (P = 0.0023) and lipid rich plaque (P = 0.0015) compared with homogeneous neointima. The neointimal tissue characteristics may change over time after SES implantation. The incidence of heterogeneous pattern was higher in the SES group with longer follow-up duration. Microvessels and lipid rich plaques were more frequently observed in neointima with heterogeneous pattern. Neointimal heterogeneity could be an important factor for the late stability of SES.