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Coronary Artery Disease: HELP
Articles by Ryo Torii
Based on 11 articles published since 2008
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Between 2008 and 2019, Ryo Torii wrote the following 11 articles about Coronary Artery Disease.
 
+ Citations + Abstracts
1 Editorial Biodegradable vascular scaffold: is optimal expansion the key to minimising flow disturbances and risk of adverse events? 2015

Foin, Nicolas / Torii, Ryo / Mattesini, Alessio / Wong, Philip / Di Mario, Carlo. ·National Heart Centre Singapore, Singapore. ·EuroIntervention · Pubmed #25420789.

ABSTRACT: -- No abstract --

2 Review Local Hemodynamic Forces After Stenting: Implications on Restenosis and Thrombosis. 2017

Ng, Jaryl / Bourantas, Christos V / Torii, Ryo / Ang, Hui Ying / Tenekecioglu, Erhan / Serruys, Patrick W / Foin, Nicolas. ·From the National Heart Centre Singapore (J.N., H.Y.A., N.F.) · Department of Biomedical Engineering, National University of Singapore, Singapore (J.N.) · Departments of Cardiovascular Sciences (C.V.B.) and Mechanical Engineering (R.T.), University College London, United Kingdom · Department of Cardiology, Barts Health NHS Trust, London, United Kingdom (C.V.B.) · Thoraxcenter, Erasmus MC, Rotterdam Erasmus University, The Netherlands (E.T., P.W.S.) · National Heart & Lung Institute, Imperial College London, United Kingdom (P.W.S.) · and Duke-NUS Medical School, National University of Singapore (N.F.). ·Arterioscler Thromb Vasc Biol · Pubmed #29122816.

ABSTRACT: Local hemodynamic forces are well-known to modulate atherosclerotic evolution, which remains one of the largest cause of death worldwide. Percutaneous coronary interventions with stent implantation restores blood flow to the downstream myocardium and is only limited by stent failure caused by restenosis, stent thrombosis, or neoatherosclerosis. Cumulative evidence has shown that local hemodynamic forces affect restenosis and the platelet activation process, modulating the pathophysiological mechanisms that lead to stent failure. This article first covers the pathophysiological mechanisms through which wall shear stress regulates arterial disease formation/neointima proliferation and the role of shear rate on stent thrombosis. Subsequently, the article reviews the current evidence on (1) the implications of stent design on the local hemodynamic forces, and (2) how stent/scaffold expansion can influence local flow, thereby affecting the risk of adverse events.

3 Review Intravascular multimodality imaging: feasibility and role in the evaluation of coronary plaque pathology. 2017

Michail, Michael / Serruys, Patrick W / Stettler, Rodrigue / Crake, Tom / Torii, Ryo / Tenekecioglu, Erhan / Zeng, Yaping / Onuma, Yoshinobu / Mathur, Anthony / Bourantas, Christos V. ·Barts Heart Centre, Barts Health NHS Trust, London, UK. · Faculty of Medicine, National Heart & Lung Institute, Imperial College London, UK. · Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, The Netherlands. · Department of Mechanical Engineering, University College London, UK. · Department of Cardiovascular Sciences, University College London, UK. ·Eur Heart J Cardiovasc Imaging · Pubmed #28329320.

ABSTRACT: Coronary artery disease remains the leading cause of death in the developed world. Over recent years, research has been focused on the development of diagnostic intravascular imaging techniques that enable assessment of plaque composition and morphology, and allow identification of vulnerable, high-risk lesions. Nevertheless recent studies of coronary atherosclerosis have shown that invasive modalities have a limited accuracy in detecting lesions that will progress and cause events, whilst histology-based studies also highlighted the limitations of invasive imaging in assessing plaque characteristics. To overcome these drawbacks, multimodality imaging has been proposed. Although it is apparent that coronary imaging with two or three imaging modalities is time consuming and is associated with a risk of complications, evidence from small clinical studies demonstrated that it provides incremental information about plaque pathology and biology and underscored the need to develop dual-probe hybrid imaging catheters that would enable complete and comprehensive assessment of plaque morphology. This paper reviews the current clinical evidence that supports the use of multimodality intravascular imaging in the study of atherosclerosis, summarizes the key findings of the first invasive imaging studies that utilize hybrid dual-probe catheters, and discusses the limitations of combined intravascular imaging that restrict its broad application in both the clinical and research arena.

4 Review Vulnerable plaque detection: an unrealistic quest or a feasible objective with a clinical value? 2016

Bourantas, Christos V / Garcia-Garcia, Hector M / Torii, Ryo / Zhang, Yao-Jun / Westwood, Mark / Crake, Tom / Serruys, Patrick W. ·Department of Cardiovascular Sciences, University College London, London, UK Department of Cardiology, Barts Heart Centre, London, UK. · Department of Interventional Cardiology, Erasmus MC, Thoraxcenter, Rotterdam, The Netherlands. · Department of Mechanical Engineering, University College London, London, UK. · Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Nanjing, China. · Department of Cardiology, Barts Heart Centre, London, UK. · Department of Interventional Cardiology, Erasmus MC, Thoraxcenter, Rotterdam, The Netherlands Faculty of Medicine, National Heart & Lung Institute, Imperial College London, London, UK. ·Heart · Pubmed #26783236.

ABSTRACT: Evidence from the first prospective studies of coronary atherosclerosis demonstrated that intravascular imaging has limited accuracy in detecting lesions that are likely to progress and cause future events, and divided the scientific community into experts who advocate abandoning this quest and others who suggest intensifying our efforts improve and optimise the available imaging techniques. Although the current evidence may not justify the use of invasive or non-invasive imaging in the clinical setting for the detection of vulnerable, high-risk lesions, it is apparent that imaging has provided unique insights about plaque pathophysiology and evolution. Recent evidence indicates that both invasive and non-invasive imaging also provides useful prognostic information in patients with established coronary artery disease and in asymptomatic individuals and is likely to enable more accurate risk stratification. Future studies are anticipated to provide further insights about the value of novel hybrid imaging techniques, which are expected to enable complete assessment of plaque pathophysiology, in detecting vulnerable lesions and identifying high-risk patients that would benefit from new aggressive treatments targeting coronary atherosclerosis.

5 Clinical Trial The Effect of Strut Protrusion on Shear Stress Distribution: Hemodynamic Insights From a Prospective Clinical Trial. 2017

Tenekecioglu, Erhan / Torii, Ryo / Sotomi, Yohei / Collet, Carlos / Dijkstra, Jouke / Miyazaki, Yosuke / Crake, Tom / Su, Solomon / Costa, Ricardo / Chámie, Daniel / Liew, Houng-Bang / Santoso, Teguh / Onuma, Yoshinobu / Abizaid, Alexander / Bourantas, Christos V / Serruys, Patrick W. · ·JACC Cardiovasc Interv · Pubmed #28882287.

ABSTRACT: -- No abstract --

6 Article Implications of the local hemodynamic forces on the formation and destabilization of neoatherosclerotic lesions. 2018

Torii, Ryo / Stettler, Rodrigue / Räber, Lorenz / Zhang, Yao-Jun / Karanasos, Antonis / Dijkstra, Jouke / Patel, Kush / Crake, Tom / Hamshere, Steve / Garcia-Garcia, Hector M / Tenekecioglu, Erhan / Ozkor, Muhiddin / Baumbach, Andreas / Windecker, Stephan / Serruys, Patrick W / Regar, Evelyn / Mathur, Anthony / Bourantas, Christos V. ·Department of Mechanical Engineering, University College London, London, United Kingdom. · Barts Heart Centre, Barts Health NHS, London, United Kingdom. · Bern University Hospital, Bern, Switzerland. · Xuzhou Third People's Hospital, Jiangsu University, Xuzhou, China; Nanjing First Hospital, Nanjing Medical University, Nanjing, China. · Thoraxcenter, Erasmus Medical Centre, Rotterdam, the Netherlands. · Leiden University Medical Centre, Leiden, the Netherlands. · Barts Heart Centre, Barts Health NHS, London, United Kingdom; Queen Mary University London, London, United Kingdom. · Thoraxcenter, Erasmus Medical Centre, Rotterdam, the Netherlands; Faculty of Medicine, National Heart & Lung Institute, Imperial College London, United Kingdom. · Department of Cardiovascular Surgery, University Hospital Zürich, Zürich, Switzerland. · Barts Heart Centre, Barts Health NHS, London, United Kingdom; Queen Mary University London, London, United Kingdom; Institute of Cardiovascular Sciences, University College London, London, United Kingdom. Electronic address: Christos.Bourantas@bartshealth.nhs.uk. ·Int J Cardiol · Pubmed #30293579.

ABSTRACT: OBJECTIVE: To examine the implications of endothelial shear stress (ESS) distribution in the formation of neoatherosclerotic lesions. METHODS: Thirty six patients with neoatherosclerotic lesions on optical coherence tomography (OCT) were included in this study. The OCT data were used to reconstruct coronary anatomy. Blood flow simulation was performed in the models reconstructed from the stent borders which it was assumed that represented the lumen surface at baseline, immediate after stent implantation, and the estimated ESS was associated with the neointima burden, neoatherosclerotic burden and neointima characteristics. In segments with neointima rupture blood flow simulation was also performed in the model representing the lumen surface before rupture and the ESS was estimated at the ruptured site. RESULTS: An inverse association was noted between baseline ESS and the incidence and the burden of neoatherosclerotic (β = -0.60, P < 0.001, and β = -4.05, P < 0.001, respectively) and lipid-rich neoatherosclerotic tissue (β = -0.54, P < 0.001, and β = -3.60, P < 0.001, respectively). Segments exposed to low ESS (<1 Pa) were more likely to exhibit macrophages accumulation (28.2% vs 10.9%, P < 0.001), thrombus (11.0% vs 2.6%, P < 0.001) and evidence of neointima discontinuities (8.1% vs 0.9%, P < 0.001) compared to those exposed to normal or high ESS. In segments with neointima rupture the ESS was high at the rupture site compared to the average ESS over the culprit lesion (4.00 ± 3.65 Pa vs 3.14 ± 2.90 Pa, P < 0.001). CONCLUSIONS: Local EES is associated with neoatherosclerotic lesion characteristics, which suggests involvement of ESS in the formation of vulnerable plaques in stented segments.

7 Article Neointima and neoatherosclerotic characteristics in bare metal and first- and second-generation drug-eluting stents in patients admitted with cardiovascular events attributed to stent failure: an optical coherence tomography study. 2018

Stettler, Rodrigue / Dijkstra, Jouke / Räber, Lorenz / Torii, Ryo / Zhang, Yao-Jun / Karanasos, Antonios / Lui, Shengnan / Crake, Tom / Hamshere, Steve / Garcia-Garcia, Hector M / Tenekecioglu, Erhan / Ozkor, Muhiddin / Windecker, Stephan / Serruys, Patrick W / Regar, Evelyn / Mathur, Anthony / Bourantas, Christos V. ·Barts Heart Centre, Barts Health NHS Trust, London, United Kingdom. ·EuroIntervention · Pubmed #28606888.

ABSTRACT: AIMS: The aim of this study was to assess neoatherosclerotic plaque morphology in bare metal (BMS) and first- and second-generation drug-eluting stents (DES) in patients presenting with an event attributed to stent failure. METHODS AND RESULTS: Thirty-five patients (11 implanted with BMS, 13 with a first-generation and 11 with a second-generation DES) admitted with an event due to stent failure who had neoatherosclerotic lesions on optical coherence tomography were included in the analysis. The lumen and stent borders were detected and the lipid and calcific tissue were identified in the neointima and their burden was estimated. The neointima attenuation and backscatter indices were computed and compared between the different stent types. Although there were no differences in the neointima burden, the BMS group exhibited thinner fibrous caps (p<0.001), and a numerically increased incidence of lipid-rich plaques (p=0.052) and macrophage accumulation (p=0.012). Neointima discontinuities (p=0.009) and thrombus (p=0.032) were seen more often in first-generation DES. In all stent types, neoatherosclerosis had focal manifestations. In neoatherosclerotic lesions the attenuation and backscatter indices were increased in BMS (p=0.031 and p=0.018, respectively) compared to DES; however, there were no differences between stents in the attenuation indices in subsegments located distally to neoatherosclerotic lesions which had low values in all stent types. CONCLUSIONS: Although there are differences in lipid burden and neointima characteristics in different stent types, in all stents neoatherosclerosis has focal manifestations indicating that, irrespective of the stent type, focal triggers are involved in the generation of vulnerable neolesions.

8 Article Early coverage of drug-eluting stents analysed by optical coherence tomography: evidence of the impact of stent apposition and strut characteristics on the neointimal healing process. 2016

Lee, Renick / Foin, Nicolas / Ng, Jaryl / Allen, John / Soh, Nicole / Ang, Ivy / Shim, Winston / Torii, Ryo / Wong, Philip. ·National Heart Centre Singapore, Singapore. ·EuroIntervention · Pubmed #27497360.

ABSTRACT: AIMS: Previous studies have associated issues such as incomplete stent apposition with delayed healing and adverse events (stent thrombosis). The aim of this study was to evaluate the impact of strut apposition and stent type on the progression of stent strut coverage. METHODS AND RESULTS: We evaluated in vivo in porcine models the follow-up response and coverage characteristics of well-apposed and malapposed segments of drug-eluting stents (DES) (CYPHER, PROMUS Element and Orsiro) and the Absorb bioresorbable vascular scaffold (BVS) by optical coherence tomography (OCT) sequentially, at baseline, and at one week and four weeks of follow-up. Supporting results were provided by histological analysis performed at four-week follow-up and computer simulation describing the shear characteristics around apposed and non-apposed struts. A total of 325 cross-sections containing 3,166 struts were analysed. The extent of malapposition decreased over time as a result of neointimal healing (from 7.1% at baseline to 0% at four weeks; p=0.03). At one week, 13.6% of struts in well-apposed segments were still uncovered versus 19.2% of struts in malapposed cross-sections and 77.8% of NASB struts (p<0.01). At four-week follow-up, 3.1% of struts were uncovered in well-apposed cross-sections vs. 1.6% in malapposed cross-sections and 35.7% of NASB struts (p<0.01). A comparison of the apposed segments revealed that the thin-strut Orsiro had only 1.3% of uncovered struts at one week while PROMUS Element, CYPHER and BVS had 6.6%, 48.4% and 16.2% of struts still uncovered, respectively. CONCLUSIONS: This study shows that early coverage is influenced by stent apposition as well as platform strut characteristics (stent type). At four weeks, NASB struts remained a focus of delayed endothelialisation.

9 Article Local Hemodynamics: An Innocent Bystander or a Critical Factor Regulating Neoatherosclerotic Evolution? 2015

Michail, Michael / Torii, Ryo / Crake, Tom / Ozkor, Muhiddin / Garcia-Garcia, Hector M / Tenekecioglu, Erhan / Onuma, Yoshinobu / Mathur, Anthony / Serruys, Patrick W / Bourantas, Christos V. ·The Heart Hospital, University College London Hospitals NHS Foundation Trust, London, United Kingdom. · Department of Mechanical Engineering, University College London, London, United Kingdom. · Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, the Netherlands. · Department of Cardiology, Barts Heart Center, Bart's Health NHS Trust, London, United Kingdom. · Department of Interventional Cardiology, Erasmus University Medical Centre, Thoraxcenter, Rotterdam, the Netherlands; Faculty of Medicine, National Heart & Lung Institute, Imperial College London, United Kingdom. · The Heart Hospital, University College London Hospitals NHS Foundation Trust, London, United Kingdom; Department of Cardiovascular Sciences, University College London, United Kingdom. Electronic address: cbourantas@gmail.com. ·JACC Cardiovasc Interv · Pubmed #26210805.

ABSTRACT: -- No abstract --

10 Article Incomplete stent apposition causes high shear flow disturbances and delay in neointimal coverage as a function of strut to wall detachment distance: implications for the management of incomplete stent apposition. 2014

Foin, Nicolas / Gutiérrez-Chico, Juan Luis / Nakatani, Shimpei / Torii, Ryo / Bourantas, Christos V / Sen, Sayan / Nijjer, Sukhjinder / Petraco, Ricardo / Kousera, Chrysa / Ghione, Matteo / Onuma, Yoshinobu / Garcia-Garcia, Hector M / Francis, Darrel P / Wong, Philip / Di Mario, Carlo / Davies, Justin E / Serruys, Patrick W. ·From the International Centre for Circulatory Health, NHLI, Imperial College London, London, United Kingdom (N.F., S.S., S.N., R.P., C.K., D.P.F., J.E.D., P.W.S.) · National Heart Centre Singapore, Singapore (N.F., P.W.) · ThoraxCenter, Erasmus Medical Center, Rotterdam, The Netherlands (J.L.G.-C., S.N., C.V.B., Y.O., H.M.G.-G., P.W.S.) · Ludwig-Maximilian Universität, München, Germany (J.L.G.-C.) · Department of Mechanical Engineering, University College London, London, United Kingdom (R.T.) · NIHR, BRU, Royal Brompton and Harefield NHS Trust, London, United Kingdom (M.G., C.D.M.) · and Cardialysis, Rotterdam, The Netherlands (H.M.G.-G., P.W.S.). ·Circ Cardiovasc Interv · Pubmed #24642998.

ABSTRACT: BACKGROUND: Lack of re-endothelialization and neointimal coverage on stent struts has been put forward as the main underlying mechanism leading to late stent thrombosis. Incomplete stent apposition (ISA) has been observed frequently in patients with very late stent thrombosis after drug eluting stent implantation, suggesting a role of ISA in the pathogenesis of this adverse event. The aim of this study was to evaluate the impact of different degrees of ISA severity on abnormal shear rate and healing response with coverage, because of its potential implications for stent optimization in clinical practice. METHODS AND RESULTS: We characterized flow profile and shear distribution in different cases of ISA with increasing strut-wall detachment distance (ranging from 100 to 500 μm). Protruding strut and strut malapposed with moderate detachment (ISA detachment distance <100 μm) have minimal disturbance to blood flow as compared with floating strut that has more significant ISA distance. In vivo impact on strut coverage was assessed retrospectively using optical coherence tomography evaluation on 72 stents (48 patients) sequentially at baseline and after 6-month follow-up. Analysis of coverage revealed an important impact of baseline strut-wall ISA distance on the risk of incomplete strut coverage at follow-up. Malapposed segments with an ISA detachment <100 μm at baseline showed complete strut coverage at follow-up, whereas segments with a maximal ISA detachment distance of 100 to 300 μm and >300 μm had 6.1% and 15.7% of their struts still uncovered at follow-up, respectively (P<0.001). CONCLUSIONS: Flow disturbances and risk of delayed strut coverage both increase with ISA detachment distance. Insights from this study are important for understanding malapposition as a quantitative, rather than binary phenomenon (present or absent) and to define the threshold of ISA detachment that might benefit from optimization during stent implantation.

11 Article Kissing balloon or sequential dilation of the side branch and main vessel for provisional stenting of bifurcations: lessons from micro-computed tomography and computational simulations. 2012

Foin, Nicolas / Torii, Ryo / Mortier, Peter / De Beule, Mathieu / Viceconte, Nicola / Chan, Pak Hei / Davies, Justin E / Xu, Xiao Yun / Krams, Rob / Di Mario, Carlo. ·Department of Bioengineering, Imperial College London, London, United Kingdom. nicolas.foin@ic.ac.uk ·JACC Cardiovasc Interv · Pubmed #22230150.

ABSTRACT: OBJECTIVES: This study sought to evaluate post-dilation strategies in bifurcation stenting. BACKGROUND: In bifurcation stenting practice, it is still controversial how post-dilation should be performed and whether the kissing balloon (KB) technique is mandatory when only the main vessel (MV) receives a stent. METHODS: A series of drug-eluting stents (DES) (n = 26) were deployed in a coronary bifurcation model following a provisional approach. After the deployment of the stent in the MV, post-dilation with the KB technique was compared with a 2-step, sequential post-dilation of the side branch (SB) and MV without kissing. RESULTS: The percentage of the SB lumen area free of stent struts was similar after KB (79.1 ± 8.7%) and after the 2-step sequence (74.4 ± 11.6%, p = 0.25), a considerable improvement compared with MV stenting only without dilation of the stent at the SB ostium (30.8 ± 7.8%, p < 0.0001). The rate of strut malapposition in the ostium was 21.3 ± 9.2% after KB and 24.9 ± 10.4% after the 2-step sequence, respectively, a significant reduction compared with a simple SB dilation (55.3 ± 16.8%, p < 0.0001) or MV stenting only (47.0 ± 8.5%, p < 0.0005). KB created a significant elliptical overexpansion of the MV lumen, inducing higher stress concentration proximal to the SB. KB also led to a higher risk of incomplete stent apposition at the proximal stent edge (30.7 ± 26.4% vs. 2.8 ± 9.6% for 2-step, p = 0.0016). CONCLUSIONS: Sequential 2-step post-dilation of the SB and MV may offer a simpler and more efficient alternative to final KB technique for provisional stenting of bifurcations.