1. Articles from Akihiro Nakajima

    1-14 of 14
    1. Optical coherence tomography in coronary atherosclerosis assessment and intervention

      Optical coherence tomography in coronary atherosclerosis assessment and intervention

      Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing ...

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    2. Layered Plaque Characteristics and Layer Burden in Acute Coronary Syndromes

      Layered Plaque Characteristics and Layer Burden in Acute Coronary Syndromes

      Recently, layered plaque, an optical coherence tomography equivalent of healed plaque, has been gaining attention. However, detailed layered plaque characteristics including the burden of plaque layer have not been investigated. Patients with acute coronary syndromes who underwent preintervention optical coherence tomography imaging of culprit lesion were included. Layer index, a product of the mean layer arc and layer length, was correlated with the pattern of layer and culprit pathology. In addition, layer index was compared between culprit and nonculprit plaques. Finally, predictors for greater layer index were identified using general linear modeling. In 349 patients, 99 culprit plaques had layered ...

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    3. Optical Coherence Tomography of Coronary Plaque Progression and Destabilization: JACC Focus Seminar Part 3/3

      Optical Coherence Tomography of Coronary Plaque Progression and Destabilization: JACC Focus Seminar Part 3/3

      The development of optical coherence tomography (OCT) has revolutionized our understanding of coronary artery disease. In vivo OCT research has paralleled with advances in computational fluid dynamics, providing additional insights in the various hemodynamic factors influencing plaque growth and stability. Recent OCT studies introduced a new concept of plaque healing in relation to clinical presentation. In addition to known mechanisms of acute coronary syndromes such as plaque rupture and plaque erosion, a new classification of calcified plaque was recently reported. This review will focus on important new insights that OCT has provided in recent years into coronary plaque development, progression ...

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    4. Coronary plaque and clinical characteristics of South Asian (Indian) patients with acute coronary syndromes: An optical coherence tomography study

      Coronary plaque and clinical characteristics of South Asian (Indian) patients with acute coronary syndromes: An optical coherence tomography study

      Background South Asians, and Indians in particular, are known to have a higher incidence of premature atherosclerosis and acute coronary syndromes (ACS) with worse clinical outcomes, compared to populations with different ethnic backgrounds. However, the underlying pathobiology accounting for these differences has not been fully elucidated. Methods ACS patients who had culprit lesion optical coherence tomography (OCT) imaging were enrolled. Culprit plaque characteristics were evaluated using OCT. Results Among 1315 patients, 100 were South Asian, 1009 were East Asian, and 206 were White. South Asian patients were younger (South Asians vs. East Asians vs. Whites: 51.6 ± 13.4 vs ...

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    5. Predictors for Rapid Progression of Coronary Calcification: An Optical Coherence Tomography Study

      Predictors for Rapid Progression of Coronary Calcification: An Optical Coherence Tomography Study

      Background The role of coronary calcification in cardiovascular events and plaque stabilization is still being debated, and factors involved in the progression of coronary calcification are not fully understood. This study aimed to identify the predictors for rapid progression of coronary calcification. Methods and Results Patients with serial optical coherence tomography imaging at baseline and at 6 months were selected. Changes in the calcification index and predictors for progression of calcification were studied. Calcification index was defined as the product of the mean calcification arc and calcification length. Rapid progression of calcification was defined as an increase in the calcification ...

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    6. Optical Coherence Tomography Predictors for a Favorable Vascular Response to Statin Therapy

      Optical Coherence Tomography Predictors for a Favorable Vascular Response to Statin Therapy

      Background Specific plaque phenotypes that predict a favorable response to statin therapy have not been systematically studied. This study aimed to identify optical coherence tomography predictors for a favorable vascular response to statin therapy. Methods and Results Patients who had serial optical coherence tomography imaging at baseline and at 6 months were included. Thin‐cap area (defined as an area with fibrous cap thickness <200 μm) was measured using a 3‐dimensional computer‐aided algorithm, and changes in the thin‐cap area at 6 months were calculated. A favorable vascular response was defined as the highest tertile in the degree ...

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    7. Predictors of Rapid Plaque Progression: An Optical Coherence Tomography Study

      Predictors of Rapid Plaque Progression: An Optical Coherence Tomography Study

      Objectives This study sought to identify morphological predictors of rapid plaque progression. Background Two patterns of plaque progression have been described: slow linear progression and rapid step-wise progression. The former pattern will cause stable angina when the narrowing reaches a critical threshold, whereas the latter pattern may lead to acute coronary syndromes or sudden cardiac death. Methods Patients who underwent optical coherence tomography (OCT) imaging during the index procedure and follow-up angiography with a minimum interval of 6 months were selected. Nonculprit lesions with a diameter stenosis of ≥30% on index angiography were assessed. Lesion progression was defined as a ...

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    8. Relation of Low-Density Lipoprotein Cholesterol Level to Plaque Rupture

      Relation of Low-Density Lipoprotein Cholesterol Level to Plaque Rupture

      Statin therapy reduces low-density lipoprotein cholesterol (LDL-C), inflammation, and atherosclerotic cardiovascular disease. We investigated the association between LDL-C and statin therapy on the prevalence of plaque rupture (PR). Patients with acute coronary syndromes who underwent optical coherence tomography imaging of the culprit lesion were divided into 4 groups based on LDL-C level and statin use (Group 1: LDL-C ≤ 100 without statin; Group 2; LDL-C ≤ 100 with statin; Group 3: LDL-C >100 with statin; Group 4: LDL-C >100 without statin), and the prevalence of PR was compared between the groups. Among 896 patients, PR was diagnosed in 444 (49.6%) patients ...

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    9. Circadian variations in pathogenesis of ST-segment elevation myocardial infarction: an optical coherence tomography study

      Circadian variations in pathogenesis of ST-segment elevation myocardial infarction: an optical coherence tomography study

      Previous studies have reported a circadian variation in the onset of ST-segment elevation myocardial infarction (STEMI). However, underlying mechanisms for the circadian variation have not been fully elucidated. We investigated the relationship between onset of STEMI and the underlying pathology using optical coherence tomography (OCT). Patients with a diagnosis of STEMI were selected from a multicenter OCT registry. Patients were divided into 4 groups based on the estimated time of onset (00:00–05:59, 06:00–11:59, 12:00–17:59, or 18:00–23:59). Underlying pathologies of MI (plaque rupture, plaque erosion, and calcified plaque) were ...

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    10. Degree of luminal narrowing and composition of thrombus in plaque erosion

      Degree of luminal narrowing and composition of thrombus in plaque erosion

      As the degree of luminal narrowing increases, shear stress increases, and high shear stress is known to activate platelets. However, the relationship between the degree of luminal narrowing and the composition of thrombus in patients with plaque erosion has not been studied. A total of 148 patients with plaque erosion and thrombus detected by optical coherence tomography were divided into tertiles based on the minimum lumen area (MLA) at the culprit lesion. Thrombus was categorized as platelet-rich or fibrin-rich. Among 148 patients, 50 (34%) were in the mild stenosis group, 49 (33%) were in the moderate stenosis group, and 49 ...

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    11. Comparison of post‐stent optical coherence tomography findings: Layered versus non‐layered culprit lesions

      Comparison of post‐stent optical coherence tomography findings: Layered versus non‐layered culprit lesions

      Objectives This study aimed to investigate the vascular response of lesions with a layered phenotype. Background Recent studies have shown that layered plaques at culprit lesions detected by optical coherence tomography (OCT) have greater plaque burden and more inflammatory features than non‐layered plaques. Methods This is a retrospective observational study. A total of 193 target lesions from 193 patients [100 patients with acute coronary syndromes (ACS) and 93 with stable angina pectoris (SAP)] who had undergone OCT imaging of the culprit lesion both before and after stenting were included. Layered plaques were identified by OCT as plaques with layers ...

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    12. COMPARISON OF POST STENT OPTICAL COHERENCE TOMOGRAPHY FINDINGS AMONG THREE SUBTYPES OF CALCIFIED CULPRIT PLAQUES IN PATIENTS WITH ACUTE CORONARY SYNDROME

      COMPARISON OF POST STENT OPTICAL COHERENCE TOMOGRAPHY FINDINGS AMONG THREE SUBTYPES OF CALCIFIED CULPRIT PLAQUES IN PATIENTS WITH ACUTE CORONARY SYNDROME

      Background Recently, three subtypes of calcified plaques at the culprit lesion were reported in patients with acute coronary syndrome (ACS): eruptive calcified nodule, superficial calcific sheet, and calcified protrusion. Methods A total of 157 patients with ACS and calcified plaque at the culprit lesion were selected from our database. Optical coherence tomography (OCT) findings at index procedure and after stent implantation were compared among the three subgroups. Results In the final analysis, 92 cases were included. Pre-procedural OCT showed eruptive calcified nodules in 20 (21.7%) cases, superficial calcific sheets in 66 (71.7%), and calcified protrusion in 6 (6 ...

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    13. Comparison of post‐stent optical coherence tomography findings among three subtypes of calcified culprit plaques in patients with acute coronary syndrome

      Comparison of post‐stent optical coherence tomography findings among three subtypes of calcified culprit plaques in patients with acute coronary syndrome

      Objectives To compare the postprocedural optical coherence tomography (OCT) findings and in‐hospital outcomes among the three subtypes of calcified plaques: eruptive calcified nodules, superficial calcific sheet, and calcified protrusion. Background Recently, three subtypes of calcified culprit plaques were reported in patients with acute coronary syndrome (ACS). How these subtypes respond to stenting is unknown. Methods ACS patients with calcified plaque at the culprit lesion were selected from our database. OCT findings at baseline and after stent implantation were compared. Results In the final analysis, 87 cases were included. Preprocedural OCT showed eruptive calcified nodules in 19 (21.8%) cases ...

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    1-14 of 14
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    Comparison of post‐stent optical coherence tomography findings among three subtypes of calcified culprit plaques in patients with acute coronary syndrome COMPARISON OF POST STENT OPTICAL COHERENCE TOMOGRAPHY FINDINGS AMONG THREE SUBTYPES OF CALCIFIED CULPRIT PLAQUES IN PATIENTS WITH ACUTE CORONARY SYNDROME Comparison of post‐stent optical coherence tomography findings: Layered versus non‐layered culprit lesions Degree of luminal narrowing and composition of thrombus in plaque erosion Circadian variations in pathogenesis of ST-segment elevation myocardial infarction: an optical coherence tomography study Relation of Low-Density Lipoprotein Cholesterol Level to Plaque Rupture Predictors of Rapid Plaque Progression: An Optical Coherence Tomography Study Optical Coherence Tomography Predictors for a Favorable Vascular Response to Statin Therapy Predictors for Rapid Progression of Coronary Calcification: An Optical Coherence Tomography Study Optical Coherence Tomography of Coronary Plaque Progression and Destabilization: JACC Focus Seminar Part 3/3 Optical coherence tomography findings in patients with transfusion-dependent β-thalassemia Higher-order regression three-dimensional motion-compensation method for real-time optical coherence tomography volumetric imaging of the cornea