Takashi Akasaka - Academia.edu (original) (raw)

Papers by Takashi Akasaka

Research paper thumbnail of Myocardial salvage for ST-elevation myocardial infarction with terminal QRS distortion and restoration of brisk epicardial coronary flow

Heart and Vessels, Mar 1, 2009

Research paper thumbnail of OCT: Ready for Prime Time?

Research paper thumbnail of Outcome of Percutaneous Coronary Intervention in Unstable Angina Pectoris Versus Stable Angina Pectoris in Two Different Time Periods

The American Journal of Cardiology, 2006

Percutaneous coronary intervention (PCI) for unstable angina pectoris (UAP) has traditionally bee... more Percutaneous coronary intervention (PCI) for unstable angina pectoris (UAP) has traditionally been associated with a higher risk of ischemic complications than that for stable angina pectoris (SAP). However, PCI procedures have evolved, so this study was designed to determine whether PCI for UAP is still associated with less favorable outcomes. In-hospital and 1-year outcomes in Dynamic Registry patients who presented for PCI with UAP (n = 2,994) or SAP (n = 1,457) between 1997 and 2002 were compared. One-year results were also compared with consecutive patients who underwent angioplasty (n = 2,431) from the 1985 to 1986 Percutaneous Transluminal Coronary Angioplasty Registry. Although Dynamic Registry patients with UAP were older and more likely to smoke (p < 0.05), have diabetes mellitus (p = 0.03), or a previous myocardial infarction (p < 0.001), procedural success was higher than in patients with SAP. By 1 year, there was greater risk of death (4.4% vs 2.6%, p < 0.01), death/myocardial infarction (9.9% vs 6.6%, p < 0.001), and death, myocardial infarction, and coronary artery bypass grafting (15.1% vs 11.6%, p < 0.01) in patients with UAP. In patients with UAP, there was no significant difference in adjusted 1-year death and death/myocardial infarction rates when comparing the waves of the Dynamic Registry with those of the Percutaneous Transluminal Coronary Angioplasty Registry, although death/myocardial infarction rates among Dynamic Registry patients were lower. However, in patients with SAP, the adjusted rate for death/myocardial infarction was lower in wave 3, and for death, myocardial infarction, and revascularization, there was a significant decrease in event rates with each successive recruitment period (p < 0.05 for all comparisons). In conclusion, in contradistinction to patients with SAP, death and death/myocardial infarction rates in patients who have undergone PCI for UAP have not significantly decreased over the past 16 years and patients with UAP remain at a greater risk of ischemic events at 1 year compared with patients with SAP.

Research paper thumbnail of Optical frequency domain imaging vs. intravascular ultrasound in percutaneous coronary intervention (OPINION trial): one-year angiographic and clinical results

Eur Heart J, 2017

Aims Optical frequency domain imaging (OFDI) is a recently developed, light-based, high-resolutio... more Aims Optical frequency domain imaging (OFDI) is a recently developed, light-based, high-resolution intravascular imaging technique. Intravascular ultrasound (IVUS) is a widely used, conventional imaging technique for guiding percutaneous coronary intervention (PCI). We aimed to demonstrate the non-inferiority of OFDI-guided PCI compared with IVUS-guided PCI in terms of clinical outcomes.

Research paper thumbnail of ifference of Culprit Lesion Morphologies etween ST-Segment Elevation Myocardial nfarction and Non – ST-Segment Elevation cute Coronary Syndrome n Optical Coherence Tomography Study

esults The incidence of plaque rupture, thin-cap fibroatheroma, and red thrombus was signifiantly... more esults The incidence of plaque rupture, thin-cap fibroatheroma, and red thrombus was signifiantly higher in STEMI compared with NSTEACS (70% vs. 47%, p 0.033, 78% vs. 49%, p 0.008, nd 78% vs. 27%, p 0.001, respectively). Although the lumen area at the site of plaque rupture as similar in the both groups (2.44 1.34 mm vs. 2.96 1.91 mm, p 0.250), the area of rupured cavity was significantly larger in STEMI compared with NSTEACS (2.52 1.36 mm vs. 1.67 .37 mm, p 0.034). Furthermore, the ruptured plaque of which aperture was open-wide against he direction of coronary flow was more often seen in STEMI compared with NSTEACS (46% vs. 17%, 0.036).

Research paper thumbnail of OCT : Ready for Prime Time ? Clinical applications of optical coherence tomography

Research paper thumbnail of A Local Multi-Layer Model for Tissue Classification of in-vivo Atherosclerotic Plaques in Intravascular Optical Coherence Tomography

IEICE Transactions on Information and Systems, 2019

Xinbo REN †, † †a) , Student Member, Haiyuan WU †b) , Member, Qian CHEN † † †c) , Toshiyuki IMAI ... more Xinbo REN †, † †a) , Student Member, Haiyuan WU †b) , Member, Qian CHEN † † †c) , Toshiyuki IMAI †d) , Takashi KUBO † † † †e) , and Takashi AKASAKA † † † †f) , Nonmembers SUMMARY Clinical researches show that the morbidity of coronary artery disease (CAD) is gradually increasing in many countries every year, and it causes hundreds of thousands of people all over the world dying for each year. As the optical coherence tomography with high resolution and better contrast applied to the lesion tissue investigation of human vessel, many more micro-structures of the vessel could be easily and clearly visible to doctors, which help to improve the CAD treatment effect. Manual qualitative analysis and classification of vessel lesion tissue are time-consuming to doctors because a single-time intravascular optical coherence (IVOCT) data set of a patient usually contains hundreds of in-vivo vessel images. To overcome this problem, we focus on the investigation of the superficial layer of the lesion region and propose a model based on local multi-layer region for vessel lesion components (lipid, fibrous and calcified plaque) features characterization and extraction. At the pre-processing stage, we applied two novel automatic methods to remove the catheter and guidewire respectively. Based on the detected lumen boundary, the multi-layer model in the proximity lumen boundary region (PLBR) was built. In the multi-layer model, features extracted from the A-line sub-region (ALSR) of each layer was employed to characterize the type of the tissue existing in the ALSR. We used 7 human datasets containing total 490 OCT images to assess our tissue classification method. Validation was obtained by comparing the manual assessment with the automatic results derived by our method. The proposed automatic tissue classification method achieved an average accuracy of 89.53%, 93.81% and 91.78% for fibrous, calcified and lipid plaque respectively.

Research paper thumbnail of Late clinical outcome of suboptimal stent implantation defined by intracoronary optical coherence tomography

EuroIntervention, 2018

Optical coherence tomography (OCT) is an intravascular imaging technique that provides high-resol... more Optical coherence tomography (OCT) is an intravascular imaging technique that provides high-resolution (10-20 μm) images. During percutaneous coronary intervention (PCI), OCT offers useful information to guide treatment strategies and assess optimal stent implantation (Figure 1). However, OCT remains markedly

Research paper thumbnail of Benefit of Distal Protection During Percutaneous Coronary Intervention in Properly Selected Patients

JACC: Cardiovascular Interventions, 2018

Research paper thumbnail of Clinical Impact of Coronary Computed Tomography Angiography-Derived Fractional Flow Reserve on Japanese Population in the ADVANCE Registry

Circulation Journal, 2019

tional guidelines strongly endorse invasive FFR in the management of CAD patients. 4 However, the... more tional guidelines strongly endorse invasive FFR in the management of CAD patients. 4 However, the adoption of FFR is limited in the real world and its invasive nature is thought to be a major hindrance to its use. 5 Coronary computed tomography angiography (cCTA)-P hysiological assessment is paramount in the management of patients with coronary artery disease (CAD). Invasive fractional flow reserve (FFR) has proven to have excellent diagnostic accuracy and to improve the clinical outcome. 1-3 As a result, the interna

Research paper thumbnail of Continuous development of neoatherosclerosis beyond a decade after drug-eluting stent implantation

EuroIntervention, 2018

Coronary stents are widely used for the treatment of patients with coronary artery disease. Drug-... more Coronary stents are widely used for the treatment of patients with coronary artery disease. Drug-eluting stents (DES) have reduced the rate of late restenosis compared with bare metal stents (BMS). However, late and very late stent thrombosis have become a major concern in DES. Pathological findings from patients who died of very late DES thrombosis have demonstrated that incomplete re-endothelialisation, late acquired stent malapposition, and atherosclerosis within neointima (known as neoatherosclerosis) are important underlying substrates of very late DES thrombosis 1. Rupture of neoatherosclerosis is the most common mechanism of very late DES thrombosis. Neoatherosclerosis in DES occurs earlier compared with BMS and develops continuously. e 1257 EuroIntervention 2018;14:e1255-e1257 Neoatherosclerosis beyond a decade after DES Usui et al 2 , comprehensive risk factor control and optimal medical therapy seem to be necessary for the long period of beyond a decade to prevent very late stent failure in patients treated with DES.

Research paper thumbnail of Comparison of neointimal coverage between everolimus-eluting stents and sirolimus-eluting stents: an optical coherence tomography substudy of the RESET (Randomized Evaluation of Sirolimus-eluting versus Everolimus-eluting stent Trial)

EuroIntervention : journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, Jan 22, 2015

The aim of the present study was to compare vascular healing response between the first-generatio... more The aim of the present study was to compare vascular healing response between the first-generation sirolimus-eluting stent (SES) and the second-generation everolimus-eluting stent (EES) by using optical coherence tomography (OCT). The RESET was a prospective, multicentre, randomised, open-label trial comparing EES and SES. Of the 3,197 patients enrolled in the RESET, nine-month follow-up OCT after stent implantation was performed in 100 patients (48 EES-treated lesions in 44 patients and 62 SES-treated lesions in 56 patients), thus constituting the OCT substudy population. The percentage of uncovered struts per lesion (8±15% vs. 14±19%, p=0.031) and cross-sections with >30% uncovered struts per lesion (6±14% vs. 18±29%, p=0.009) was significantly lower in EES compared with SES. The frequency of DES-treated lesions with incomplete stent apposition (8 [17%] vs. 29 [47%], p<0.001) was significantly lower in EES compared with SES. Intra-stent thrombus was comparably observed betwe...

Research paper thumbnail of Application of Optical Coherence Tomography in Percutaneous Coronary Intervention

Circulation Journal, 2012

ptical coherence tomography (OCT) is a novel intravascular imaging modality that uses near-infrar... more ptical coherence tomography (OCT) is a novel intravascular imaging modality that uses near-infrared light. The distinct advantage of OCT over conventional intravascular ultrasound (IVUS) is its ultra-high resolution (10-20 μm). OCT provides new opportunities to perform detailed analysis of the coronary artery wall, including plaque characterization, identification of unstable plaque, and assessment of the vascular response in relation to percutaneous coronary intervention (PCI). 1,2 This review focuses on the usefulness of OCT in PCI. OCT System and Technique The OCT system consists of a light source, reference mirror, and photodetector. Compared with the initial time-domain (TD) OCT, newer generations of intravascular OCT systems, termed frequency-domain (FD) OCT, use a fixed mirror with a variable frequency light source, which makes image acquisition significantly faster. The pullback speed of the OCT catheter is up to 20 mm/s, and the scanning length reaches 50 mm. In addition, FD-OCT imaging can be achieved during contrast injection from a guiding catheter (<15 ml, 3-4 ml/s). The fast scanning speed of FD-OCT could be related to its clinical utility and patient safety. FD-OCT has a shorter procedure time and less ischemic symptoms during OCT image acquisition as compared to TD-OCT. 3,4 Quantitative Measurements OCT provides robust and reproducible measurements of the vessel lumen. The high resolution of OCT images allows accurate recognition of the luminal boundary. When OCT was performed in a plexiglass phantom manufactured with a precision of 10 μm, the OCT measurement correlated extremely well with the real luminal dimension (relative standard deviation 1.8%, r=1.000, intercept 0.01, slope 1.02). 5 In addition, the correlation between the measurements of OCT and IVUS was highly significant (R 2 =0.82, P<0.001). 6 However, the luminal area measured by OCT seems to be smaller than that with IVUS, and the relative difference is approximately 11-22%. 6,7 The difference between the 2 methods could be related to the specific backscattering of either light or sound. The recognition of the luminal boundary might be inherently different because of the physical characteristics of the wave length used by these technologies. Moreover, the Z-offset, which is a manually adjustable calibration of OCT, is critical for accurate measurements. A 1% change in the magnitude of the ideal Z-offset can result in a 12-14% error in area measurements by OCT. 8 The measurement bias in OCT may influence the assessment of lesion severity and device selection for PCI.

Research paper thumbnail of Optical Frequency Domain Imaging Versus Intravascular Ultrasound in Percutaneous Coronary Intervention (OPINION Trial): Results From the OPINION Imaging Study

JACC. Cardiovascular imaging, Jan 9, 2017

We sought to clarify how intravascular ultrasound (IVUS) and optical coherence tomography affect ... more We sought to clarify how intravascular ultrasound (IVUS) and optical coherence tomography affect percutaneous coronary intervention (PCI) with current-generation drug-eluting stents in a pre-specified substudy of the OPINION (OPtical frequency domain imaging versus INtravascular ultrasound in percutaneous coronary interventiON) trial, a multicenter, prospective, randomized, noninferiority trial comparing optical frequency domain imaging (OFDI)-guided PCI with IVUS-guided PCI. The impact of these 2 imaging modalities in guiding PCI remains unknown. Of 829 patients enrolled in the OPINION trial, 106 were included in the present imaging substudy. Their PCI was guided by either IVUS or OFDI, but all patients were imaged by both modalities after PCI and by OFDI at 8 months. Angiographic, OFDI, and IVUS images were analyzed by independent core laboratories, and statistical analysis was done independently by a dedicated institution. A total of 103 patients underwent either OFDI-guided (n =...

Research paper thumbnail of TCTAP A-159 Optical Coherence Tomography Assessment of Calcium Fracture by Percutaneous Coronary Intervention in Heavily Calcified Lesions

Journal of the American College of Cardiology, 2015

Research paper thumbnail of Beneficial Effect of Platelet Inhibition Against Peri-Procedural Myocardial Infarction Due to Intra-Stent Thrombus Penetration: Optical Coherence Tomography Sub-Analysis in Prasfit Elective

Journal of the American College of Cardiology, 2015

beneFiCial eFFeCt oF platelet inhibition aGainst peri-proCedUral myoCardial inFarCtion dUe to int... more beneFiCial eFFeCt oF platelet inhibition aGainst peri-proCedUral myoCardial inFarCtion dUe to intra-stent thrombUs penetration: optiCal CoherenCe tomoGraphy sUb-analysis in prasFit eleCtive

Research paper thumbnail of A new method for determining stroke volume by color Doppler flow velocity profile: Stability to a positional change of sample area

Journal of the American Society of Echocardiography, 1995

Research paper thumbnail of Serial Changes of Everolimus–Eluting Stent Incomplete Stent Apposition: An Optical Coherence Tomography Subanalysis from the Reset Trial

Journal of the American College of Cardiology, 2013

Background: The long term outcome of in complete stent apposition (ISA) after stent implantation ... more Background: The long term outcome of in complete stent apposition (ISA) after stent implantation remains unclear. The aim of this study was to evaluate serial changes of ISA after everolims-eluting stent implantation by using optical coherence tomography (OCT). methods: Randomized Evaluation of Sirolims-eluting versus Everolims-eluting stent Trial (RESET) was a prospective dual-arm randomized trial of everolims-eluting stents (EES) and sirolims-eluting stents (SES) in 3197 patients with coronary artery disease. From the RESET trial, 44 patients with everolims-eluting stents who underwent serial OCT examination (post-stenting and 12-month follow-up) were investigated. results: At post-stenting, ISA was observed in 38 (86%) EES. Mean malapposed distance (distance from stent strut to lumen surface) was 366 ± 225 μm at post-stenting. At 12-month follow-up, 27 (76%) ISA was resolved, however 9 (24%) was persistent. The mean malapposed distance was 165 ± 276 μm at 12-month follow-up. Receiver-operating curve analysis identified a malapposed distance > 410μm, (area under the curve, 0.95) as separating persistent from resolved ISA. conclusions: The stent with malapposed distance > 410μm at post-stenting has a high risk for persistent stent malapposition at 12-month followup in EES. OCT can predict persistent stent malapposition and provide useful information to optimize percutaneous coronary intervention.

Research paper thumbnail of TCT-610 Deferred Coronary Lesion With A Gray Zone Fractional Flow Reserve In Patients With Intermediate Stenosis Is At Higher Risk Of Future Coronary Events

Journal of the American College of Cardiology, 2013

Background: Non-specific chest symptoms associated with coronary artery spasm (CAS) remain underd... more Background: Non-specific chest symptoms associated with coronary artery spasm (CAS) remain underdiagnosed and consequently undertreated. Our center applies a policy of systematic CAS detection by provocative tests (PT) in normal or near normal coronary arteries in patients with symptoms compatible with vasospastic origin. We retrospectively studied the prevalence of CAS, safety of PTs and patient outcome over a 10-year period. Methods: From December 2002 to July 2012, 13,902 patients underwent 18,454 coronary angiographies. 5,962 of these patients with normal or near normal arteries underwent 2,397 PTs. 256 were consequently diagnosed with CAS (10.7%). In addition, among the 7,940 patients with a !50% stenosis on coronary angiography, 44 patients were diagnosed as having a spontaneous CAS (0.6%). Results: Compared to the overall population, patients with CAS were more often female (44.7% vs. 29.6%; p<0.0001), younger (55 [47.5-64] years vs. 61 [52-70] years; p¼0.0001), and more often smokers (63.7% vs. 42.3%; p<0.0001). Initial presentation was more frequently acute coronary syndrome (37.4% vs. 28.9%) and non-specific chest pain (41.8% vs. 21.6%). Sixty-nine patients had refractory CAS when PT was abnormal under antispastic treatment. 99.1% of the patients who underwent a PT had an event-free hospital course. At 46 months, the all-cause death rate, myocardial infarction, stroke and revascularization in CAS patients were 4.3%, 3.3%, 0% and 4.3%, respectively. Conclusions: This retrospective study of 10 years of experience suggests that CAS is present in as many as 10.7% of patients with chest symptoms at rest. PT seems to be safe in patients with normal or near normal coronary angiography. These findings could justify performing PTs more systematically in this setting to avoid the potentially severe outcomes of undiagnosed CAS.

Research paper thumbnail of Intravascular Ultrasound Imaging. In vitro and vivo validation

Japanese Circulation Journal, 1992

Research paper thumbnail of Myocardial salvage for ST-elevation myocardial infarction with terminal QRS distortion and restoration of brisk epicardial coronary flow

Heart and Vessels, Mar 1, 2009

Research paper thumbnail of OCT: Ready for Prime Time?

Research paper thumbnail of Outcome of Percutaneous Coronary Intervention in Unstable Angina Pectoris Versus Stable Angina Pectoris in Two Different Time Periods

The American Journal of Cardiology, 2006

Percutaneous coronary intervention (PCI) for unstable angina pectoris (UAP) has traditionally bee... more Percutaneous coronary intervention (PCI) for unstable angina pectoris (UAP) has traditionally been associated with a higher risk of ischemic complications than that for stable angina pectoris (SAP). However, PCI procedures have evolved, so this study was designed to determine whether PCI for UAP is still associated with less favorable outcomes. In-hospital and 1-year outcomes in Dynamic Registry patients who presented for PCI with UAP (n = 2,994) or SAP (n = 1,457) between 1997 and 2002 were compared. One-year results were also compared with consecutive patients who underwent angioplasty (n = 2,431) from the 1985 to 1986 Percutaneous Transluminal Coronary Angioplasty Registry. Although Dynamic Registry patients with UAP were older and more likely to smoke (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), have diabetes mellitus (p = 0.03), or a previous myocardial infarction (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), procedural success was higher than in patients with SAP. By 1 year, there was greater risk of death (4.4% vs 2.6%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), death/myocardial infarction (9.9% vs 6.6%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), and death, myocardial infarction, and coronary artery bypass grafting (15.1% vs 11.6%, p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) in patients with UAP. In patients with UAP, there was no significant difference in adjusted 1-year death and death/myocardial infarction rates when comparing the waves of the Dynamic Registry with those of the Percutaneous Transluminal Coronary Angioplasty Registry, although death/myocardial infarction rates among Dynamic Registry patients were lower. However, in patients with SAP, the adjusted rate for death/myocardial infarction was lower in wave 3, and for death, myocardial infarction, and revascularization, there was a significant decrease in event rates with each successive recruitment period (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05 for all comparisons). In conclusion, in contradistinction to patients with SAP, death and death/myocardial infarction rates in patients who have undergone PCI for UAP have not significantly decreased over the past 16 years and patients with UAP remain at a greater risk of ischemic events at 1 year compared with patients with SAP.

Research paper thumbnail of Optical frequency domain imaging vs. intravascular ultrasound in percutaneous coronary intervention (OPINION trial): one-year angiographic and clinical results

Eur Heart J, 2017

Aims Optical frequency domain imaging (OFDI) is a recently developed, light-based, high-resolutio... more Aims Optical frequency domain imaging (OFDI) is a recently developed, light-based, high-resolution intravascular imaging technique. Intravascular ultrasound (IVUS) is a widely used, conventional imaging technique for guiding percutaneous coronary intervention (PCI). We aimed to demonstrate the non-inferiority of OFDI-guided PCI compared with IVUS-guided PCI in terms of clinical outcomes.

Research paper thumbnail of ifference of Culprit Lesion Morphologies etween ST-Segment Elevation Myocardial nfarction and Non – ST-Segment Elevation cute Coronary Syndrome n Optical Coherence Tomography Study

esults The incidence of plaque rupture, thin-cap fibroatheroma, and red thrombus was signifiantly... more esults The incidence of plaque rupture, thin-cap fibroatheroma, and red thrombus was signifiantly higher in STEMI compared with NSTEACS (70% vs. 47%, p 0.033, 78% vs. 49%, p 0.008, nd 78% vs. 27%, p 0.001, respectively). Although the lumen area at the site of plaque rupture as similar in the both groups (2.44 1.34 mm vs. 2.96 1.91 mm, p 0.250), the area of rupured cavity was significantly larger in STEMI compared with NSTEACS (2.52 1.36 mm vs. 1.67 .37 mm, p 0.034). Furthermore, the ruptured plaque of which aperture was open-wide against he direction of coronary flow was more often seen in STEMI compared with NSTEACS (46% vs. 17%, 0.036).

Research paper thumbnail of OCT : Ready for Prime Time ? Clinical applications of optical coherence tomography

Research paper thumbnail of A Local Multi-Layer Model for Tissue Classification of in-vivo Atherosclerotic Plaques in Intravascular Optical Coherence Tomography

IEICE Transactions on Information and Systems, 2019

Xinbo REN †, † †a) , Student Member, Haiyuan WU †b) , Member, Qian CHEN † † †c) , Toshiyuki IMAI ... more Xinbo REN †, † †a) , Student Member, Haiyuan WU †b) , Member, Qian CHEN † † †c) , Toshiyuki IMAI †d) , Takashi KUBO † † † †e) , and Takashi AKASAKA † † † †f) , Nonmembers SUMMARY Clinical researches show that the morbidity of coronary artery disease (CAD) is gradually increasing in many countries every year, and it causes hundreds of thousands of people all over the world dying for each year. As the optical coherence tomography with high resolution and better contrast applied to the lesion tissue investigation of human vessel, many more micro-structures of the vessel could be easily and clearly visible to doctors, which help to improve the CAD treatment effect. Manual qualitative analysis and classification of vessel lesion tissue are time-consuming to doctors because a single-time intravascular optical coherence (IVOCT) data set of a patient usually contains hundreds of in-vivo vessel images. To overcome this problem, we focus on the investigation of the superficial layer of the lesion region and propose a model based on local multi-layer region for vessel lesion components (lipid, fibrous and calcified plaque) features characterization and extraction. At the pre-processing stage, we applied two novel automatic methods to remove the catheter and guidewire respectively. Based on the detected lumen boundary, the multi-layer model in the proximity lumen boundary region (PLBR) was built. In the multi-layer model, features extracted from the A-line sub-region (ALSR) of each layer was employed to characterize the type of the tissue existing in the ALSR. We used 7 human datasets containing total 490 OCT images to assess our tissue classification method. Validation was obtained by comparing the manual assessment with the automatic results derived by our method. The proposed automatic tissue classification method achieved an average accuracy of 89.53%, 93.81% and 91.78% for fibrous, calcified and lipid plaque respectively.

Research paper thumbnail of Late clinical outcome of suboptimal stent implantation defined by intracoronary optical coherence tomography

EuroIntervention, 2018

Optical coherence tomography (OCT) is an intravascular imaging technique that provides high-resol... more Optical coherence tomography (OCT) is an intravascular imaging technique that provides high-resolution (10-20 μm) images. During percutaneous coronary intervention (PCI), OCT offers useful information to guide treatment strategies and assess optimal stent implantation (Figure 1). However, OCT remains markedly

Research paper thumbnail of Benefit of Distal Protection During Percutaneous Coronary Intervention in Properly Selected Patients

JACC: Cardiovascular Interventions, 2018

Research paper thumbnail of Clinical Impact of Coronary Computed Tomography Angiography-Derived Fractional Flow Reserve on Japanese Population in the ADVANCE Registry

Circulation Journal, 2019

tional guidelines strongly endorse invasive FFR in the management of CAD patients. 4 However, the... more tional guidelines strongly endorse invasive FFR in the management of CAD patients. 4 However, the adoption of FFR is limited in the real world and its invasive nature is thought to be a major hindrance to its use. 5 Coronary computed tomography angiography (cCTA)-P hysiological assessment is paramount in the management of patients with coronary artery disease (CAD). Invasive fractional flow reserve (FFR) has proven to have excellent diagnostic accuracy and to improve the clinical outcome. 1-3 As a result, the interna

Research paper thumbnail of Continuous development of neoatherosclerosis beyond a decade after drug-eluting stent implantation

EuroIntervention, 2018

Coronary stents are widely used for the treatment of patients with coronary artery disease. Drug-... more Coronary stents are widely used for the treatment of patients with coronary artery disease. Drug-eluting stents (DES) have reduced the rate of late restenosis compared with bare metal stents (BMS). However, late and very late stent thrombosis have become a major concern in DES. Pathological findings from patients who died of very late DES thrombosis have demonstrated that incomplete re-endothelialisation, late acquired stent malapposition, and atherosclerosis within neointima (known as neoatherosclerosis) are important underlying substrates of very late DES thrombosis 1. Rupture of neoatherosclerosis is the most common mechanism of very late DES thrombosis. Neoatherosclerosis in DES occurs earlier compared with BMS and develops continuously. e 1257 EuroIntervention 2018;14:e1255-e1257 Neoatherosclerosis beyond a decade after DES Usui et al 2 , comprehensive risk factor control and optimal medical therapy seem to be necessary for the long period of beyond a decade to prevent very late stent failure in patients treated with DES.

Research paper thumbnail of Comparison of neointimal coverage between everolimus-eluting stents and sirolimus-eluting stents: an optical coherence tomography substudy of the RESET (Randomized Evaluation of Sirolimus-eluting versus Everolimus-eluting stent Trial)

EuroIntervention : journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, Jan 22, 2015

The aim of the present study was to compare vascular healing response between the first-generatio... more The aim of the present study was to compare vascular healing response between the first-generation sirolimus-eluting stent (SES) and the second-generation everolimus-eluting stent (EES) by using optical coherence tomography (OCT). The RESET was a prospective, multicentre, randomised, open-label trial comparing EES and SES. Of the 3,197 patients enrolled in the RESET, nine-month follow-up OCT after stent implantation was performed in 100 patients (48 EES-treated lesions in 44 patients and 62 SES-treated lesions in 56 patients), thus constituting the OCT substudy population. The percentage of uncovered struts per lesion (8±15% vs. 14±19%, p=0.031) and cross-sections with >30% uncovered struts per lesion (6±14% vs. 18±29%, p=0.009) was significantly lower in EES compared with SES. The frequency of DES-treated lesions with incomplete stent apposition (8 [17%] vs. 29 [47%], p<0.001) was significantly lower in EES compared with SES. Intra-stent thrombus was comparably observed betwe...

Research paper thumbnail of Application of Optical Coherence Tomography in Percutaneous Coronary Intervention

Circulation Journal, 2012

ptical coherence tomography (OCT) is a novel intravascular imaging modality that uses near-infrar... more ptical coherence tomography (OCT) is a novel intravascular imaging modality that uses near-infrared light. The distinct advantage of OCT over conventional intravascular ultrasound (IVUS) is its ultra-high resolution (10-20 μm). OCT provides new opportunities to perform detailed analysis of the coronary artery wall, including plaque characterization, identification of unstable plaque, and assessment of the vascular response in relation to percutaneous coronary intervention (PCI). 1,2 This review focuses on the usefulness of OCT in PCI. OCT System and Technique The OCT system consists of a light source, reference mirror, and photodetector. Compared with the initial time-domain (TD) OCT, newer generations of intravascular OCT systems, termed frequency-domain (FD) OCT, use a fixed mirror with a variable frequency light source, which makes image acquisition significantly faster. The pullback speed of the OCT catheter is up to 20 mm/s, and the scanning length reaches 50 mm. In addition, FD-OCT imaging can be achieved during contrast injection from a guiding catheter (<15 ml, 3-4 ml/s). The fast scanning speed of FD-OCT could be related to its clinical utility and patient safety. FD-OCT has a shorter procedure time and less ischemic symptoms during OCT image acquisition as compared to TD-OCT. 3,4 Quantitative Measurements OCT provides robust and reproducible measurements of the vessel lumen. The high resolution of OCT images allows accurate recognition of the luminal boundary. When OCT was performed in a plexiglass phantom manufactured with a precision of 10 μm, the OCT measurement correlated extremely well with the real luminal dimension (relative standard deviation 1.8%, r=1.000, intercept 0.01, slope 1.02). 5 In addition, the correlation between the measurements of OCT and IVUS was highly significant (R 2 =0.82, P<0.001). 6 However, the luminal area measured by OCT seems to be smaller than that with IVUS, and the relative difference is approximately 11-22%. 6,7 The difference between the 2 methods could be related to the specific backscattering of either light or sound. The recognition of the luminal boundary might be inherently different because of the physical characteristics of the wave length used by these technologies. Moreover, the Z-offset, which is a manually adjustable calibration of OCT, is critical for accurate measurements. A 1% change in the magnitude of the ideal Z-offset can result in a 12-14% error in area measurements by OCT. 8 The measurement bias in OCT may influence the assessment of lesion severity and device selection for PCI.

Research paper thumbnail of Optical Frequency Domain Imaging Versus Intravascular Ultrasound in Percutaneous Coronary Intervention (OPINION Trial): Results From the OPINION Imaging Study

JACC. Cardiovascular imaging, Jan 9, 2017

We sought to clarify how intravascular ultrasound (IVUS) and optical coherence tomography affect ... more We sought to clarify how intravascular ultrasound (IVUS) and optical coherence tomography affect percutaneous coronary intervention (PCI) with current-generation drug-eluting stents in a pre-specified substudy of the OPINION (OPtical frequency domain imaging versus INtravascular ultrasound in percutaneous coronary interventiON) trial, a multicenter, prospective, randomized, noninferiority trial comparing optical frequency domain imaging (OFDI)-guided PCI with IVUS-guided PCI. The impact of these 2 imaging modalities in guiding PCI remains unknown. Of 829 patients enrolled in the OPINION trial, 106 were included in the present imaging substudy. Their PCI was guided by either IVUS or OFDI, but all patients were imaged by both modalities after PCI and by OFDI at 8 months. Angiographic, OFDI, and IVUS images were analyzed by independent core laboratories, and statistical analysis was done independently by a dedicated institution. A total of 103 patients underwent either OFDI-guided (n =...

Research paper thumbnail of TCTAP A-159 Optical Coherence Tomography Assessment of Calcium Fracture by Percutaneous Coronary Intervention in Heavily Calcified Lesions

Journal of the American College of Cardiology, 2015

Research paper thumbnail of Beneficial Effect of Platelet Inhibition Against Peri-Procedural Myocardial Infarction Due to Intra-Stent Thrombus Penetration: Optical Coherence Tomography Sub-Analysis in Prasfit Elective

Journal of the American College of Cardiology, 2015

beneFiCial eFFeCt oF platelet inhibition aGainst peri-proCedUral myoCardial inFarCtion dUe to int... more beneFiCial eFFeCt oF platelet inhibition aGainst peri-proCedUral myoCardial inFarCtion dUe to intra-stent thrombUs penetration: optiCal CoherenCe tomoGraphy sUb-analysis in prasFit eleCtive

Research paper thumbnail of A new method for determining stroke volume by color Doppler flow velocity profile: Stability to a positional change of sample area

Journal of the American Society of Echocardiography, 1995

Research paper thumbnail of Serial Changes of Everolimus–Eluting Stent Incomplete Stent Apposition: An Optical Coherence Tomography Subanalysis from the Reset Trial

Journal of the American College of Cardiology, 2013

Background: The long term outcome of in complete stent apposition (ISA) after stent implantation ... more Background: The long term outcome of in complete stent apposition (ISA) after stent implantation remains unclear. The aim of this study was to evaluate serial changes of ISA after everolims-eluting stent implantation by using optical coherence tomography (OCT). methods: Randomized Evaluation of Sirolims-eluting versus Everolims-eluting stent Trial (RESET) was a prospective dual-arm randomized trial of everolims-eluting stents (EES) and sirolims-eluting stents (SES) in 3197 patients with coronary artery disease. From the RESET trial, 44 patients with everolims-eluting stents who underwent serial OCT examination (post-stenting and 12-month follow-up) were investigated. results: At post-stenting, ISA was observed in 38 (86%) EES. Mean malapposed distance (distance from stent strut to lumen surface) was 366 ± 225 μm at post-stenting. At 12-month follow-up, 27 (76%) ISA was resolved, however 9 (24%) was persistent. The mean malapposed distance was 165 ± 276 μm at 12-month follow-up. Receiver-operating curve analysis identified a malapposed distance > 410μm, (area under the curve, 0.95) as separating persistent from resolved ISA. conclusions: The stent with malapposed distance > 410μm at post-stenting has a high risk for persistent stent malapposition at 12-month followup in EES. OCT can predict persistent stent malapposition and provide useful information to optimize percutaneous coronary intervention.

Research paper thumbnail of TCT-610 Deferred Coronary Lesion With A Gray Zone Fractional Flow Reserve In Patients With Intermediate Stenosis Is At Higher Risk Of Future Coronary Events

Journal of the American College of Cardiology, 2013

Background: Non-specific chest symptoms associated with coronary artery spasm (CAS) remain underd... more Background: Non-specific chest symptoms associated with coronary artery spasm (CAS) remain underdiagnosed and consequently undertreated. Our center applies a policy of systematic CAS detection by provocative tests (PT) in normal or near normal coronary arteries in patients with symptoms compatible with vasospastic origin. We retrospectively studied the prevalence of CAS, safety of PTs and patient outcome over a 10-year period. Methods: From December 2002 to July 2012, 13,902 patients underwent 18,454 coronary angiographies. 5,962 of these patients with normal or near normal arteries underwent 2,397 PTs. 256 were consequently diagnosed with CAS (10.7%). In addition, among the 7,940 patients with a !50% stenosis on coronary angiography, 44 patients were diagnosed as having a spontaneous CAS (0.6%). Results: Compared to the overall population, patients with CAS were more often female (44.7% vs. 29.6%; p<0.0001), younger (55 [47.5-64] years vs. 61 [52-70] years; p¼0.0001), and more often smokers (63.7% vs. 42.3%; p<0.0001). Initial presentation was more frequently acute coronary syndrome (37.4% vs. 28.9%) and non-specific chest pain (41.8% vs. 21.6%). Sixty-nine patients had refractory CAS when PT was abnormal under antispastic treatment. 99.1% of the patients who underwent a PT had an event-free hospital course. At 46 months, the all-cause death rate, myocardial infarction, stroke and revascularization in CAS patients were 4.3%, 3.3%, 0% and 4.3%, respectively. Conclusions: This retrospective study of 10 years of experience suggests that CAS is present in as many as 10.7% of patients with chest symptoms at rest. PT seems to be safe in patients with normal or near normal coronary angiography. These findings could justify performing PTs more systematically in this setting to avoid the potentially severe outcomes of undiagnosed CAS.

Research paper thumbnail of Intravascular Ultrasound Imaging. In vitro and vivo validation

Japanese Circulation Journal, 1992