Publications
155 results found
Savvopoulos F, Keeling MC, Carassiti D, et al., 2024, Assessment of the nano-mechanical properties of healthy and atherosclerotic coronary arteries by atomic force microscopy., J R Soc Interface, Vol: 21
Nano-indentation techniques might be better equipped to assess the heterogeneous material properties of plaques than macroscopic methods but there are no bespoke protocols for this kind of material testing for coronary arteries. Therefore, we developed a measurement protocol to extract mechanical properties from healthy and atherosclerotic coronary artery tissue sections. Young's modulus was derived from force-indentation data. Metrics of collagen fibre density were extracted from the same tissue, and the local material properties were co-registered to the local collagen microstructure with a robust framework. The locations of the indentation were retrospectively classified by histological category (healthy, plaque, lipid-rich, fibrous cap) according to Picrosirius Red stain and adjacent Hematoxylin & Eosin and Oil-Red-O stains. Plaque tissue was softer (p < 0.001) than the healthy coronary wall. Areas rich in collagen within the plaque (fibrous cap) were significantly (p < 0.001) stiffer than areas poor in collagen/lipid-rich, but less than half as stiff as the healthy coronary media. Young's moduli correlated (Pearson's ρ = 0.53, p < 0.05) with collagen content. Atomic force microscopy (AFM) is capable of detecting tissue stiffness changes related to collagen density in healthy and diseased cardiovascular tissue. Mechanical characterization of atherosclerotic plaques with nano-indentation techniques could refine constitutive models for computational modelling.
Cheng K, Tan S-T, Wechalekar K, et al., 2024, Redistribution of myocardial perfusion after coronary sinus reducer implantation demonstrated by rubidium-82 positron emission tomography, Journal of Nuclear Cardiology, ISSN: 1071-3581
Fogell NAT, Patel M, Yang P, et al., 2023, Considering the influence of coronary motion on artery-specific biomechanics using fluid-structure interaction simulation, Annals of Biomedical Engineering, Vol: 51, Pages: 1950-1964, ISSN: 0090-6964
The endothelium in the coronary arteries is subject to wall shear stress and vessel wall strain, which influences the biology of the arterial wall. This study presents vessel-specific fluid-structure interaction (FSI) models of three coronary arteries, using directly measured experimental geometries and boundary conditions. FSI models are used to provide a more physiologically complete representation of vessel biomechanics, and have been extended to include coronary bending to investigate its effect on shear and strain. FSI both without- and with-bending resulted in significant changes in all computed shear stress metrics compared to CFD (p = 0.0001). Inclusion of bending within the FSI model produced highly significant changes in Time Averaged Wall Shear Stress (TAWSS) + 9.8% LAD, + 8.8% LCx, - 2.0% RCA; Oscillatory Shear Index (OSI) + 208% LAD, 0% LCx, + 2600% RCA; and transverse wall Shear Stress (tSS) + 180% LAD, + 150% LCx and + 200% RCA (all p < 0.0001). Vessel wall strain was homogenous in all directions without-bending but became highly anisotropic under bending. Changes in median cyclic strain magnitude were seen for all three vessels in every direction. Changes shown in the magnitude and distribution of shear stress and wall strain suggest that bending should be considered on a vessel-specific basis in analyses of coronary artery biomechanics.
Ferreira PF, Banerjee A, Scott AD, et al., 2022, Accelerating Cardiac Diffusion Tensor Imaging With a U-Net Based Model: Toward Single Breath-Hold, JOURNAL OF MAGNETIC RESONANCE IMAGING, Vol: 56, Pages: 1691-1704, ISSN: 1053-1807
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- Citations: 4
Cheng K, Keramida G, Baksi AJ, et al., 2022, Implantation of the coronary sinus reducer for refractory angina due to coronary microvascular dysfunction in the context of apical hypertrophic cardiomyopathy-a case report, European Heart Journal: Case Reports, Vol: 6, ISSN: 2514-2119
Background:Refractory angina leads to a poor quality of life and increased healthcare resource utilization. In this growing population of patients, multiple mechanism(s) of ischaemia may co-exist, including functional disorders of the coronary microcirculation. There are few evidence-based effective therapies resulting in a large unmet clinical need.Case summary:A 38-year-old woman with refractory angina was referred with daily chest pain despite multiple anti-anginal medications and previous percutaneous coronary intervention. Cardiac magnetic resonance imaging demonstrated apical hypertrophic cardiomyopathy (HCM). Rubidium-82 positron emission tomography (PET) with regadenoson stress confirmed significant myocardial ischaemia in the apex and apical regions (16% of total myocardium) with a global myocardial perfusion reserve (MPR) of 1.23. Coronary angiography confirmed patent stents and no epicardial coronary artery disease. Therefore, the mechanism of ischaemia was thought attributable to coronary microvascular dysfunction (CMD) in the context of HCM. In view of her significant symptoms and large burden of left-sided myocardial ischaemia, a Coronary Sinus Reducer (CSR) was implanted. Repeat PET imaging at 6 months showed a marked reduction in ischaemia (<5% burden), improvement in global MPR (1.58), symptoms, and quality of life.Conclusion:In refractory angina, ischaemia may be due to disorders of both the epicardial and coronary microcirculations. The CSR is a potential therapy for these patients, but its mechanism of action has not been confirmed. This report suggests that CSR implantation may reduce myocardial ischaemia and improve symptoms by acting on the coronary microcirculation. The efficacy of CSR in patients with CMD and its mechanism of action on the coronary microcirculation warrant further investigation.
Androulakis E, Azzu A, Surkova E, et al., 2022, Quantitative cardiovascular magnetic resonance perfusion mapping as a guide for diagnosis, Publisher: OXFORD UNIV PRESS, Pages: 2313-2313, ISSN: 0195-668X
Cheng K, de Silva R, 2022, Refractory microvascular angina in hypertrophic cardiomyopathy: a novel therapy?, EUROPEAN HEART JOURNAL-CASE REPORTS, Vol: 6
Genereux P, Chernin G, Assali AR, et al., 2022, Double-blind, placebo-controlled evaluation of biorest liposomal alendronate in diabetic patients undergoing PCI: The BLADE-PCI trial, AMERICAN HEART JOURNAL, Vol: 249, Pages: 45-56, ISSN: 0002-8703
Mittal T, Evans E, Pottle A, et al., 2022, MINDFULNESS-BASED INTERVENTION IN PATIENTS WITH PERSISTENT PAIN IN CHEST (MIPIC) OF NON-CARDIAC CAUSE: A FEASIBILITY RANDOMISED-CONTROL STUDY, Annual Conference of the British-Cardiovascular-Society - 100 Years of Cardiology, Publisher: BMJ PUBLISHING GROUP, Pages: A139-A140, ISSN: 1355-6037
Mittal TK, Evans E, Pottle A, et al., 2022, Mindfulness-based intervention in patients with persistent pain in chest (MIPIC) of non-cardiac cause: a feasibility randomised control study, OPEN HEART, Vol: 9, ISSN: 2053-3624
Scott A, Jackson T, Khalique Z, et al., 2022, Development of a CMR compatible large animal isolated heart model for direct comparison of beating and arrested hearts, NMR in Biomedicine, Vol: 35, ISSN: 0952-3480
BackgroundCardiac motion results in image artefacts and quantification errors in many cardiovascular magnetic resonance (CMR) techniques, including microstructural assessment using diffusion tensor cardiovascular magnetic resonance (DT-CMR). Here we develop a CMR compatible isolated perfused porcine heart model that allows comparison of data obtained in beating and arrested states.Methods10 porcine hearts (8/10 for protocol optimisation) were harvested using a donor heart retrieval protocol and transported to the remote CMR facility. Langendorff perfusion in a 3D printed chamber and perfusion circuit re-established contraction. Hearts were imaged using cine, parametric mapping and STEAM DT-CMR at cardiac phases with the minimum and maximum wall thickness. High potassium and lithium perfusates were then used to arrest the heart in a slack and contracted state respectively. Imaging was repeated in both arrested states. After imaging, tissue was removed for subsequent histology in a location matched to the DT-CMR data using fiducial markers.ResultsRegular sustained contraction was successfully established in 6/10 hearts, including the final 5 hearts. Imaging was performed in 4 hearts and one underwent the full protocol including co-localised histology. Image quality was good and there was good agreement between DT-CMR data in equivalent beating and arrested states. Despite the use of autologous blood and dextran within the perfusate, T2, DT-CMR measures and an increase in mass was consistent with development of myocardial edema resulting in failure to achieve a true diastolic-like state. A contiguous stack of 313 5μm histological sections at and a 100μm thick section showing cell morphology on 3D fluorescent confocal microscopy co-localised to DT-CMR data were obtained.ConclusionsA CMR compatible isolated perfused beating heart setup for large animal hearts allows direct comparisons of beating and arrested heart data with subsequent co-localised histology without
Ono M, Tomaniak M, Koenig W, et al., 2022, Impact of white blood cell count on clinical outcomes in patients treated with aspirin-free ticagrelor monotherapy after percutaneous coronary intervention: insights from the GLOBAL LEADERS trial, EUROPEAN HEART JOURNAL-CARDIOVASCULAR PHARMACOTHERAPY, Vol: 8, Pages: 39-47, ISSN: 2055-6837
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- Citations: 5
de Silva R, Cheng K, 2021, Microvascular angina: quo tendimus?, EUROPEAN HEART JOURNAL, Vol: 42, Pages: 4601-4604, ISSN: 0195-668X
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- Citations: 7
Patel M, Savvopoulos F, Berggren CC, et al., 2021, Considerations for analysis of endothelial shear stress and strain in FSI models of atherosclerosis, JOURNAL OF BIOMECHANICS, Vol: 128, ISSN: 0021-9290
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- Citations: 4
Naser J, Fogell N, Patel M, et al., 2021, Moving shear stress towards the clinic: preclinical comparison of optical coherence tomography-based versus angiography-based time-averaged wall shear stress estimations, Publisher: OXFORD UNIV PRESS, Pages: 1195-1195, ISSN: 0195-668X
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- Citations: 1
Ponticelli F, Khokhar AA, Leenders G, et al., 2021, Safety and efficacy of coronary sinus narrowing in chronic refractory angina: Insights from the RESOURCE study, INTERNATIONAL JOURNAL OF CARDIOLOGY, Vol: 337, Pages: 29-37, ISSN: 0167-5273
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- Citations: 7
Naser J, Mein CA, Wozniak E, et al., 2021, PROFILING ENDOTHELIAL GENE EXPRESSION IN CORONARY ATHEROSCLEROTIC PLAQUES IN A HUMAN-LIKE D374Y-PCSK9 HYPERLIPIDAEMIC PORCINE MODEL, Publisher: BMJ PUBLISHING GROUP, Pages: A166-A167, ISSN: 1355-6037
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- Citations: 1
de Silva R, Cheng K, 2021, Reducing refractory angina., EuroIntervention, Vol: 16, Pages: e1466-e1467, ISSN: 1774-024X
Cheng K, Alhumood K, El Shaer F, et al., 2021, The role of nicorandil in the management of chronic coronary syndromes in the Gulf Region, Advances in Therapy, Vol: 38, Pages: 925-948, ISSN: 0741-238X
Chronic coronary syndromes (CCS) and stable angina are a growing clinical burden worldwide. This is of particular concern in the Gulf region given its high prevalence of cardiovascular risk factors, especially diabetes mellitus and smoking. Despite recommendations on the use of first- and second-line anti-anginal medication, management challenges remain. Current guidelines for pharmacologic treatment are not determined by the range of pathophysiological mechanisms of ischaemia and consequent angina, which may occur either in isolation or co-exist. In this article, we highlight the need to improve knowledge of the epidemiology of chronic coronary syndromes in the Middle East and Gulf region, and the need for studies of stratified pharmacologic approaches to improve symptomatic angina and quality of life in the large and growing number of patients with coronary artery disease from this region. We discuss the role of nicorandil, currently recommended as a second-line anti-anginal drug in CCS patients, and suggest that this may be a particularly useful add-on therapy for patients in the Gulf region.
Cheng K, de Silva R, 2021, TCT Connect 2020 Trial Update: FORECAST, COMBINE OCT-FFR and DEFINE-PCI, EUROPEAN CARDIOLOGY REVIEW, Vol: 16, ISSN: 1758-3756
Fair MJ, Gatehouse PD, Reyes E, et al., 2020, Initial investigation of free-breathing 3D whole-heart stress myocardial perfusion MRI., Glob Cardiol Sci Pract, Vol: 2020, ISSN: 2305-7823
Objective: Myocardial first-pass perfusion imaging with MRI is well-established clinically. However, it is potentially weakened by limited myocardial coverage compared to nuclear medicine. Clinical evaluations of whole-heart MRI perfusion by 3D methods, while promising, have to date had the limit of breathhold requirements at stress. This work aims to develop a new free-breathing 3D myocardial perfusion method, and to test its performance in a small patient population. Methods: This work required tolerance to respiratory motion for stress investigations, and therefore employed a "stack-of-stars" hybrid Cartesian-radial MRI acquisition method. The MRI sequence was highly optimised for rapid acquisition and combined with a compressed sensing reconstruction. Stress and rest datasets were acquired in four healthy volunteers, and in six patients with coronary artery disease (CAD), which were compared against clinical reference information. Results: This free-breathing method produced datasets that appeared consistent with clinical reference data in detecting moderate-to-strong induced perfusion abnormalities. However, the majority of the mild defects identified clinically were not detected by the method, potentially due to the presence of transient myocardial artefacts present in the images. Discussion: The feasibility of detecting CAD using this 3D first-pass perfusion sequence during free-breathing is demonstrated. Good agreement on typical moderate-to-strong CAD cases is promising, however, questions still remain on the sensitivity of the technique to milder cases.
Rajakulasingam R, Nielles-Vallespin S, Ferreira PF, et al., 2020, Diffusion tensor cardiovascular magnetic resonance detects altered myocardial microstructure in patients with acute st-elevation myocardial infarction, European-Society-of-Cardiology (ESC) Congress, Publisher: OXFORD UNIV PRESS, Pages: 208-208, ISSN: 0195-668X
Nielles-Vallespin S, Ferreira PF, Scott A, et al., 2020, Diffusion tensor cardiovascular magnetic resonance predicts adverse remodelling after myocardial infarction, European-Society-of-Cardiology (ESC) Congress, Publisher: OXFORD UNIV PRESS, Pages: 216-216, ISSN: 0195-668X
Tomaniak M, Katagiri Y, Modolo R, et al., 2020, Vulnerable plaques and patients: state-of-the-art, European Heart Journal, Vol: 41, Pages: 2997-3004, ISSN: 0195-668X
Despite advanced understanding of the biology of atherosclerosis, coronary heart disease remains the leading cause of death worldwide. Progress has been challenging as half of the individuals who suffer sudden cardiac death do not experience premonitory symptoms. Furthermore, it is well-recognized that also a plaque that does not cause a haemodynamically significant stenosis can trigger a sudden cardiac event, yet the majority of ruptured or eroded plaques remain clinically silent. In the past 30 years since the term 'vulnerable plaque' was introduced, there have been major advances in the understanding of plaque pathogenesis and pathophysiology, shifting from pursuing features of 'vulnerability' of a specific lesion to the more comprehensive goal of identifying patient 'cardiovascular vulnerability'. It has been also recognized that aside a thin-capped, lipid-rich plaque associated with plaque rupture, acute coronary syndromes (ACS) are also caused by plaque erosion underlying between 25% and 60% of ACS nowadays, by calcified nodule or by functional coronary alterations. While there have been advances in preventive strategies and in pharmacotherapy, with improved agents to reduce cholesterol, thrombosis, and inflammation, events continue to occur in patients receiving optimal medical treatment. Although at present the positive predictive value of imaging precursors of the culprit plaques remains too low for clinical relevance, improving coronary plaque imaging may be instrumental in guiding pharmacotherapy intensity and could facilitate optimal allocation of novel, more aggressive, and costly treatment strategies. Recent technical and diagnostic advances justify continuation of interdisciplinary research efforts to improve cardiovascular prognosis by both systemic and 'local' diagnostics and therapies. The present state-of-the-art document aims to present and critically appraise the latest evidence, developments, and future perspectives in detection, prevent
Cheng K, de Silva R, 2020, STRESS PERFUSION CARDIAC MAGNETIC RESONANCE IMAGING TO IDENTIFY CORONARY ANEURYSMS, ISCHAEMIA AND FIBROSIS IN ADULT PATIENTS WITH CONVALESCENT KAWASAKI DISEASE, Publisher: BMJ PUBLISHING GROUP, Pages: A82-A82, ISSN: 1355-6037
Rathod KS, Beirne A-M, Bogle R, et al., 2020, Prior Coronary Artery Bypass Graft Surgery and Outcome After Percutaneous Coronary Intervention: An Observational Study From the Pan-London Percutaneous Coronary Intervention Registry, JOURNAL OF THE AMERICAN HEART ASSOCIATION, Vol: 9
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- Citations: 14
Cheng K, de Silva R, 2020, Implantation of a Coronary Sinus Reducer to Treat Refractory Angina in a 38-Year-Old with an Anomalous Left Coronary Artery and No Revascularization Options, CARDIOLOGY, Vol: 145, Pages: 126-129, ISSN: 0008-6312
Jones DA, Rathod KS, Koganti S, et al., 2019, The association between the public reporting of individual operator outcomes with patient profiles, procedural management, and mortality after percutaneous coronary intervention: an observational study from the Pan-London PCI (BCIS) Registry using an interrupted time series analysis, EUROPEAN HEART JOURNAL, Vol: 40, Pages: 2620-2629, ISSN: 0195-668X
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- Citations: 6
Khan TZ, de Silva R, 2018, Is there a role for invasive assessment of the coronary microcirculation in patients with unobstructed epicardial coronary arteries in clinical practice?, International Journal of Cardiology, Vol: 267, Pages: 46-47, ISSN: 0167-5273
Jones DA, Rathod KS, Koganti S, et al., 2018, Angiography alone versus angiography plus optical coherence tomography to guide percutaneous coronary intervention: outcomes from the pan-London PCI cohort, JACC: Cardiovascular Interventions, Vol: 11, Pages: 1313-1321, ISSN: 1936-8798
OBJECTIVES: This study aimed to determine the effect on long-term survival of using optical coherence tomography (OCT) during percutaneous coronary intervention (PCI). BACKGROUND: Angiographic guidance for PCI has substantial limitations. The superior spatial resolution of OCT could translate into meaningful clinical benefits, although limited data exist to date about their effect on clinical endpoints. METHODS: This was a cohort study based on the Pan-London (United Kingdom) PCI registry, which includes 123,764 patients who underwent PCI in National Health Service hospitals in London between 2005 and 2015. Patients undergoing primary PCI or pressure wire use were excluded leaving 87,166 patients in the study. The primary endpoint was all-cause mortality at a median of 4.8 years. RESULTS: OCT was used in 1,149 (1.3%) patients, intravascular ultrasound (IVUS) was used in 10,971 (12.6%) patients, and angiography alone in the remaining 75,046 patients. Overall OCT rates increased over time (p < 0.0001), with variation in rates between centers (p = 0.002). The mean stent length was shortest in the angiography-guided group, longer in the IVUS-guided group, and longest in the OCT-guided group. OCT-guided procedures were associated with greater procedural success rates and reduced in-hospital MACE rates. A significant difference in mortality was observed between patients who underwent OCT-guided PCI (7.7%) compared with patients who underwent either IVUS-guided (12.2%) or angiography-guided (15.7%; p < 0.0001) PCI, with differences seen for both elective (p < 0.0001) and acute coronary syndrome subgroups (p = 0.0024). Overall this difference persisted after multivariate Cox analysis (hazard ratio [HR]: 0.48; 95% confidence interval [CI]: 0.26 to 0.81; p = 0.001) and propensity matching (hazard ratio: 0.39; 95% CI: 0.21 to 0.77; p = 0.0008; OCT vs. angiography-alone cohort), with no difference in matched OCT and IVUS cohorts
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