1. Articles from Young-Guk Ko

    1-24 of 60 1 2 3 »
    1. Optical Coherence Tomography for Coronary Bioresorbable Vascular Scaffold Implantation

      Optical Coherence Tomography for Coronary Bioresorbable Vascular Scaffold Implantation

      Background: We investigated whether optical coherence tomography (OCT) guidance would reduce nonoptimal bioresorbable vascular scaffold (BVS) deployment. Methods: This was a randomized controlled trial. Patients who required percutaneous coronary intervention for ischemic heart disease were recruited from 2 centers in Korea. The enrolled patients were randomly assigned to receive either OCT-guided BVS (Absorb; Abbott Vascular) implantation or angiography-guided BVS implantation using an optimized technique. The primary outcome was nonoptimal deployment, which was a composite outcome of the following parameters assessed by OCT: a minimal scaffold area <5 mm 2 , residual area stenosis >20%, incomplete apposition of the scaffold struts >5 ...

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    2. Impact of late stent malapposition after drug-eluting stent implantation on long-term clinical outcomes

      Impact of late stent malapposition after drug-eluting stent implantation on long-term clinical outcomes

      Background and aims The impact of late drug-eluting stent (DES) malapposition detected by optical coherence tomography (OCT) on long-term clinical outcomes has not been clearly established. We evaluated long-term clinical outcomes of late stent malapposition (LSM) detected by OCT in a qualified study population. Methods A total of 428 patients were selected from previous randomized OCT studies that evaluated the degree of strut coverage of different DESs at a 3–12-month follow-up OCT examination. These patients were assigned to one of two groups based on the presence (n = 136) or absence (n = 292) of LSM on follow-up OCT images (performed ...

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    3. Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

      Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

      Background Optical coherence tomography (OCT) was used to assess serial changes in severe acute stent malapposition (ASM) after drug-eluting stent (DES) implantation. Methods The maximal depth and axial lengths of ASM after DES implantation were serially quantified at percutaneous coronary intervention (PCI), and at 3 and 12-month follow-up, for 100 lesions in 96 patients. Severe ASM was defined as a maximal malapposed depth ≥400 μm or maximal malapposed axial length ≥1 mm. Results Of the 100 lesions, 23 lesions (23%) had a severe ASM depth at PCI. At 3 months, the maximal depth decreased to <400 μm in 12 of ...

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    4. Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

      Severe acute stent malapposition follow-up: 3-month and 12-month serial quantitative analyses by optical coherence tomography

      Background Optical coherence tomography (OCT) was used to assess serial changes in severe acute stent malapposition (ASM) after drug-eluting stent (DES) implantation. Methods The maximal depth and axial lengths of ASM after DES implantation were serially quantified at percutaneous coronary intervention (PCI), and at 3 and 12-month follow-up, for 100 lesions in 96 patients. Severe ASM was defined as a maximal malapposed depth ≥400 μm or maximal malapposed axial length ≥1 mm. Results Of the 100 lesions, 23 lesions (23%) had a severe ASM depth at PCI. At 3 months, the maximal depth decreased to <400 μm in 12 of ...

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    5. Early Follow-Up Optical Coherence Tomographic Findings of Significant Drug-Eluting Stent Malapposition

      Early Follow-Up Optical Coherence Tomographic Findings of Significant Drug-Eluting Stent Malapposition

      Background: Using optical coherence tomography, we evaluated early follow-up findings of significant stent malapposition (SSM) in patients treated with second-generation drug-eluting stent. Methods and Results: From the DETECT-OCT randomized trial (Determination of the Duration of the Dual Antiplatelet Therapy by the Degree of the Coverage of the Struts on Optical Coherence Tomography From the Randomized Comparison Between Everolimus- Versus Biolimus-Eluting Stent), a total of 386 patients (390 lesions) who underwent both postintervention and 3-month follow-up optical coherence tomography examinations were included for the present analysis. SSM was defined as a stent that had a strut with a maximal wall-to-strut distance ...

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    6. Randomized Comparison of Strut Coverage between Ticagrelor and Clopidogrel in Acute Myocardial Infarction at 3-Month Optical Coherence Tomography

      Randomized Comparison of Strut Coverage between Ticagrelor and Clopidogrel in Acute Myocardial Infarction at 3-Month Optical Coherence Tomography

      Purpose This study aimed to compare the effects of ticagrelor and clopidogrel on early neointimal healing assessed with optical coherence tomography (OCT) after drug-eluting stent (DES) implantation in patients with acute myocardial infarction (AMI). Materials and Methods AMI patients were randomly assigned to either the ticagrelor or clopidogrel arm. After DES implantation, OCT was performed to assess the percentages of uncovered struts immediately after procedure and 3 months later. Results Due to early termination, 83 patients out of 106 initially enrolled patients (24% of planned participants) underwent 3-month OCT. Differences in vascular healing patterns between the two groups, including percentage ...

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    7. Assessing Computational Fractional Flow Reserve From Optical Coherence Tomography in Patients With Intermediate Coronary Stenosis in the Left Anterior Descending Artery

      Assessing Computational Fractional Flow Reserve From Optical Coherence Tomography in Patients With Intermediate Coronary Stenosis in the Left Anterior Descending Artery

      Background— Intravascular optical coherence tomography (OCT) imaging provides limited information on the functional assessment of coronary stenosis. We evaluated a new approach to OCT image–based computation modeling, which can be used to estimate the fractional flow reserve (FFR) in patients with intermediate coronary stenosis. Methods and Results— Ninety-two patients with intermediate diameter stenosis in the left anterior descending artery underwent both FFR measurement with pressure wires and OCT examination. Using the OCT data, a computational fluid dynamics algorithm was used to calculate the computational FFR (FFR OCT ). The diagnostic performance of the FFR OCT was assessed based on the ...

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    8. Development of Advanced Atherosclerotic Plaque by Injection of Inflammatory Proteins in a Rabbit Iliac Artery Model

      Development of Advanced Atherosclerotic Plaque by Injection of Inflammatory Proteins in a Rabbit Iliac Artery Model

      Purpose Appropriate animal models of atherosclerotic plaque are crucial to investigating the pathophysiology of atherosclerosis, as well as for the evaluation of the efficacy and safety of vascular devices. We aimed to develop a novel animal model that would be suitable for the study of advanced atherosclerotic lesions in vivo . Materials and Methods Atherosclerotic plaque was induced in 24 iliac arteries from 12 rabbits by combining a high cholesterol diet, endothelial denudation, and injection into the vessel wall with either saline (n=5), olive oil (n=6), or inflammatory proteins [n=13, high-mobility group protein B1 (HMGB1) n=8 and ...

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    9. Association between fractional flow reserve and coronary plaque characteristics assessed by optical coherence tomography

      Association between fractional flow reserve and coronary plaque characteristics assessed by optical coherence tomography

      Background The assessment of fractional flow reserve (FFR) in coronary lesions determines the strategy of percutaneous coronary intervention. However, the association between FFR and characteristics of the underlying coronary plaque has not been sufficiently investigated. Methods A total of 110 coronary lesions in 106 patients were evaluated using both FFR and optical coherence tomography (OCT). Coronary plaques were classified into fibrous, fibrocalcific, or fibroatheroma according to OCT evaluation at the site of minimal lumen area. Plaque microstructures such as cap thickness, macrophage accumulation, intimal vasculature, or cholesterol crystals were also evaluated. Results Lesions with FFR ≤ 0.8 showed a higher ...

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    10. Favorable effect of optimal lipid-lowering therapy on neointimal tissue characteristics after drug-eluting stent implantation: Qualitative optical coherence tomographic analysis

      Favorable effect of optimal lipid-lowering therapy on neointimal tissue characteristics after drug-eluting stent implantation: Qualitative optical coherence tomographic analysis

      Objective Serial follow-up optical coherence tomography (OCT) was used to evaluate the effect of optimal lipid-lowering therapy on qualitative changes in neointimal tissue characteristics after drug-eluting stent (DES) implantation. Methods DES-treated patients (n=218) who received statin therapy were examined with serial follow-up OCT. First and second follow-up OCT evaluations were performed approximately 6 and 18 months after the index procedure, respectively. Patients were divided into two groups, based on the level of low-density lipoprotein-cholesterol (LDL-C), which was measured at the second follow-up. The optimal lipid-lowering group (n=121) had an LDL-C reduction of ≥50% or an LDL-C level ≤70mg ...

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    11. Three-dimensional optical coherence tomographic analysis of eccentric morphology of the jailed side-branch ostium in coronary bifurcation lesions

      Three-dimensional optical coherence tomographic analysis of eccentric morphology of the jailed side-branch ostium in coronary bifurcation lesions

      Background The severity of angiographic diameter stenosis of the jailed side-branch ostium is usually overestimated over the three-dimensional (3D) optical coherence tomography (OCT)-measured actual stenosis. Using the 3D-OCT, morphologic changes in the jailed side-branch ostium were evaluated before and after a single stent crossover at coronary bifurcation lesions. Methods In 109 patients who received a single stent crossover at coronary bifurcation lesions, the pre- and post-intervention minimal lumen area (MLA) and the eccentricity of the jailed side-branch ostium were measured with 3D-OCT. The eccentricity index was defined as the ratio of maximal diameter/minimal diameter of the jailed side-branch ...

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    12. Optical Coherence Tomographic Observation of In-Stent Neoatherosclerosis in Lesions With More Than 50% Neointimal Area Stenosis After Second-Generation Drug-Elnuting Stent Implantation

      Optical Coherence Tomographic Observation of In-Stent Neoatherosclerosis in Lesions With More Than 50% Neointimal Area Stenosis After Second-Generation Drug-Elnuting 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 ...

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    13. Optical Coherence Tomographic Observation of In-Stent Neoatherosclerosis in Lesions With More Than 50% Neointimal Area Stenosis After Second-Generation Drug-Eluting Stent Implantation

      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 ...

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    14. Eccentric morphology of jailed side-branch ostium after stent crossover in coronary bifurcation lesions: A three-dimensional optical coherence tomographic analysis

      Eccentric morphology of jailed side-branch ostium after stent crossover in coronary bifurcation lesions: A three-dimensional optical coherence tomographic analysis

      Background Angiographic stenosis of a jailed side-branch ostium is usually observed after a single-stent crossover at coronary bifurcation lesions. However, the stenosis severity is typically overestimated due to the limited information obtained from two-dimensional morphology by angiography. We evaluated the actual stenosis of jailed side-branch ostium using three-dimensional (3D) optical coherence tomography (OCT). Methods Using 3D reconstructions of OCT data, we analyzed minimal lumen area (MLA) and eccentricity of the jailed side-branch ostium in 41 patients who were treated with single stent crossover at coronary bifurcation lesions and subsequently underwent serial OCT follow-up. Results The MLA of jailed side-branch ostium ...

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    15. Serial randomized comparison of strut coverage between everolimus- vs. 1-generation sirolimus-eluting stents

      Serial randomized comparison of strut coverage between everolimus- vs. 1-generation sirolimus-eluting stents

      Background There has not been sufficient data to evaluate the serial vascular healing pattern after everolimus-eluting stent (EES) implantation. Using optical coherence tomography (OCT), serial changes in strut coverage were compared between EES and 1 st -generation sirolimus-eluting stents (SES). Methods Sixty patients were randomly assigned to receive either EES (n=30) or 1 st -generation SES (n=30) for coronary artery disease. Serial OCT evaluation at post-procedure, and 3- and 12-month follow-ups were performed in 50 patients with 54 stents (25 patients with 28 EES vs. 25 patients with 26 SES). The percentage of uncovered struts was defined as ...

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    16. Randomized Comparison of Stent Strut Coverage Following Angiography- or Optical Coherence Tomography-guided Percutaneous Coronary Intervention

      Randomized Comparison of Stent Strut Coverage Following Angiography- or Optical Coherence Tomography-guided Percutaneous Coronary Intervention

      Abstract Introduction and objectives The clinical benefits of optical coherence tomography-guided percutaneous coronary intervention are unclear. Therefore, in this study we sought to evaluate the impact of optical coherence tomography guidance on stent strut coverage following drug-eluting stent implantation. Methods A total of 101 patients in 105 lesions were randomly assigned to receive percutaneous coronary intervention under either optical coherence tomography guidance (n = 51 lesions of 50 patients) or angiography guidance (n = 54 lesions of 51 patients), and underwent a follow-up optical coherence tomography examination 6 months after zotarolimus-eluting stent implantation. The primary and secondary end points were the percentage ...

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    17. Serial Changes of Neointimal Tissue after Everolimus-Eluting Stent Implantation in Porcine Coronary Artery: An Optical Coherence Tomography Analysis

      Serial Changes of Neointimal Tissue after Everolimus-Eluting Stent Implantation in Porcine Coronary Artery: An Optical Coherence Tomography Analysis

      Purposes . The serial changes in neointimal tissues were compared between everolimus-eluting stent (EES) and bare-metal stent (BMS) in the porcine coronary artery using optical coherence tomography (OCT). Methods . Serial (1, 3, and 6 month follow-up after stent implantation) OCT examinations were performed in 15 swine with 15 BMS- and 15 EES-treated lesions in porcine coronary arteries. Results . In BMS-implanted lesions, neointimal volume decreased from 7.3 mm 3 to 6.9 mm 3 and 6.4 mm 3 at 1, 3, and 6 months follow-up without statistical significance ( ). At the time points of 1, 3, and 6 months, neointimal tissue ...

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    18. Optical coherence tomography-based predictors for creatine kinase-myocardial band elevation after elective percutaneous coronary intervention for in-stent restenosis

      Optical coherence tomography-based predictors for creatine kinase-myocardial band elevation after elective percutaneous coronary intervention for in-stent restenosis

      Objectives We evaluated whether morphological characteristics of neointimal tissue of in-stent restenosis (ISR) lesions assessed by optical coherence tomography (OCT) affect periprocedural elevation of creatine kinase-myocardial band (CK-MB). Background The impact of neointimal characteristics of ISR lesions on periprocedural myocardial injury has not been sufficiently investigated. Methods A total of 125 patients with ISR lesions underwent elective percutaneous coronary intervention (PCI) and pre-PCI OCT examination. Measurements of CK-MB were performed upon hospitalization, before PCI, and every 8 hr for 24 hr after PCI. CK-MB elevation was defined as levels above the 99th percentile of the upper reference limit. Neoatherosclerosis was ...

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

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

      Objectives The aim of this study was to investigate the correlation between in-stent neointimal tissue without features of neoatherosclerosis and long-term clinical outcomes. Background Recent studies have reported differential morphological characteristics of in-stent neointimal tissue assessed by optical coherence tomography (OCT). Methods The 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 ...

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

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

      Purpose The 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 Methods The 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. Results In lesions with <50% of neointimal CSA stenosis, homogeneous neointima ...

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    21. The Relationship Between Post-Stent Strut Apposition and Follow-Up Strut Coverage Assessed by a Contour Plot Optical Coherence Tomography Analysis

      The Relationship Between Post-Stent Strut Apposition and Follow-Up Strut Coverage Assessed by a Contour Plot Optical Coherence Tomography Analysis

      Objectives This study sought to evaluate the relationship between post-stent strut apposition and follow-up strut coverage using contour plot optical coherence tomographic analysis. Background Tracking the fate of interested regions of struts at different time points has not been investigated. Methods Post-intervention and 6-month follow-up optical coherence tomographic evaluations were performed in 82 patients treated with biolimus- (n = 37) or sirolimus-eluting stents (n = 45). Post-stent apposition was classified as embedded, apposed, or malapposed. For volumetric stent evaluation, the post-intervention strut-artery distance and the neointimal thickness at follow-up were measured as a function of the circumferential arc length and longitudinal stent ...

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

      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 mm 2 , respectively, between the two studies. Between the first and second OCT there was a decrease in NIH in 29 lesions ...

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    23. Mechanisms of Postintervention and Nine-Month Luminal Enlargement After Treatment of Drug-Eluting In-Stent Restenosis With a Drug-Eluting Balloon

      Mechanisms of Postintervention and Nine-Month Luminal Enlargement After Treatment of Drug-Eluting In-Stent Restenosis With a Drug-Eluting Balloon

      Using optical coherence tomography (OCT), the mechanisms of postintervention and 9-month luminal enlargement in drug-eluting stent in-stent restenosis (ISR) lesions treated with a drug-eluting balloon (DEB) were evaluated. A total of 42 patients with DEB-treated drug-eluting stent ISR lesions underwent serial OCT examination before intervention, after intervention, and at 9-month follow-up. Preintervention OCT-derived neointima was classified as either a homogeneous or nonhomogeneous pattern. Ten ISR lesions with homogeneous neointima were identified and compared with 32 ISR lesions with nonhomogeneous neointima. When comparing pre- and postintervention evaluations, changes in luminal cross-sectional area (CSA) were 3.4 mm 2 in ISR lesions ...

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    24. Randomised comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis

      Randomised comparison of strut coverage between Nobori biolimus-eluting and sirolimus-eluting stents: an optical coherence tomography analysis

      Aims: The aims of this study were to compare strut tissue coverage at six-month follow-up after Nobori biolimus-eluting stent (N-BES) versus sirolimus-eluting stent (SES) implantation. Methods and results: A total of 120 patients with a single stenotic lesion requiring revascularisation were randomly assigned to either N-BES (n=60) or SES (n=60). Baseline optical coherence tomography (OCT) was performed post stent implantation, and follow-up OCT was scheduled at six months. Post-intervention and follow-up OCT analyses were available in 51 (85.0%) and 52 (86.7%) patients, respectively. The primary endpoint was the percentage of uncovered struts at follow-up OCT in ...

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    1-24 of 60 1 2 3 »
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