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Adjedj, Julien. "Circulation coronaire : Principes et méthodes de mesure invasive du flux coronaire segmentaire en pratique clinique." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC0006/document.
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La circulation artérielle coronaire est un système complexe dont les méthodes de mesures invasivespermettent une évaluation en pratique clinique.Matériels et méthodes Nous développons, dans deux revues, les principes et méthodes des différentes techniques invasivesde mesure du flux coronaire en pratique clinique. Puis nous étudions l’impact clinique de l’utilisationde la Fractional Flow Reserve (FFR) dans l’évaluation des sténoses coronaires intermédiaires, lesmoyens pharmacologiques pour mesurer la FFR et sa corrélation avec l’évaluation angiographique enfonction des facteurs de risque cardiovasculaires. Enfin, nous décrivons les principes et méthodesd’une technique de mesure du flux coronaire segmentaire permettant d’obtenir la FFR, le flux et lesrésistances absolues avec un microcathéter de perfusion qui, sur un principe de thermodilutionpermet d’évaluer distinctement la macro et la microcirculation coronaire.Résultats Nous recommandons une valeur seuil de FFR de 0,80 pour guider la revascularisation car le nombred’événements cardiovasculaires et la mortalité sont spontanément supérieurs chez les patients avecune FFR <0,80 comparativement à une FFR ≥0,80 (9,4 vs. 4,8%, P=0,06 et 7,5 vs. 3,2%, P=0,06;respectivement). Nous avons étudié différents agents hyperémiants permettant de mesurer la FFR:l’adénosine (100 μg à 200 μg) permettant d’obtenir une hyperémie maximale, et le produit decontraste permettant d’atteindre 65% de cette hyperémie maximale. La mesure de la FFR avec duproduit de contraste permet de meilleures performances diagnostiques que les indices de reposcomparé à la FFR sous adénosine. Nous avons établi que la corrélation entre la FFR et le degré desténose angiographique est faible et inversement proportionnel au nombre de facteurs de risquecardiovasculaires, particulièrement chez les patients diabétiques. Enfin, nous avons décrit dans troisétudes, le principe de thermodilution coronaire et la méthode de mesures du flux coronaire et desrésistances microvasculaires avec un microcathéter de perfusion intracoronaire spécifique. Nousavons montré que cette technique est précise (R=0,98), qu’elle induit une hyperémie maximale etlocale sans agent hyperémiant et quelle est reproductible chez l’homme (R=0,91).Conclusion La compréhension de la circulation coronaire et l’application chez l’homme des techniques demesure du flux coronaire segmentaire sont essentielles tant en pratique clinique courante qu’enrechercheCoronary circulation is complex and highly regulated while invasive coronary flow measurements techniques allow the assessment of coronary physiology in clinical practice. Material et methods We describe in two reviews the principles and methods of different invasive coronary flowmeasurements techniques in clinical practice. We study the clinical impact of fractional flow reserve(FFR) in intermediate coronary stenosis, the hyperemic agents and dosage to measure FFR and FFRcorrelation with angiographic indices according to risk factors accumulation. Finally, we describe the principle and method of coronary flow and microvascular resistances measurements with a dedicated infusion microcatheter for coronary thermodilution to obtain assessment of macro and microvascular components of coronary circulation. Results We recommend the FFR cut off value of 0.80 to guide revascularization based on our study showing higher myocardial infarction and death rate in patients treated with medical therapy and FFR<0.80compared to those with FFR>0.80, respectively 9.4 versus 4.8%, P=0.06 and 7,5 versus 3,2%, P=0.06. We studied different hyperemic agents and dosages and showed that intracoronary adenosine at 100μg to 200 μg induce maximal hyperemia while contrast medium induce 65% of maximal hyperemia. Therefore, FFR measurements with contrast medium is feasible and has better accuracy than restindices compared to FFR. We establish the weak correlation between FFR and angiographic indicesand weakens correlation as risk factors accumulates, especially in diabetic patients. Finally, we described in three studies the method of absolute coronary flow and microvascular resistancesmeasurements based on thermodilution principle with a dedicated infusion catheter. We showed anaccurate measurement with this technique (R=0.98), which induces maximal hyperemia without theneed of hyperemic agent with reproducible measurements in humans (R=0,91).Conclusion The use of invasive coronary flow measurements to study the coronary circulation is essential inclinical practice and in research
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Lee, Chi-hang, and 李志恆. "Microvascular obstruction following percutaneous coronary interventionfor coronary artery disease." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43278723.
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Lee, Chi-hang. "Microvascular obstruction following percutaneous coronary intervention for coronary artery disease." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43278723.
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Lee, Paul Man-Yiu. "Critical coronary stenosis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq23948.pdf.
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梁永雄 and Wing-hung Leung. "Quantitative coronary arteriography." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B31981483.
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Warnes, C. A. "Sudden coronary death." Thesis, University of Newcastle Upon Tyne, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379320.
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Jensen, Jens. "On-line vectorcardiography during coronary angioplasty and unstable coronary artery disease /." Stockholm, 2000. http://diss.kib.ki.se/2000/91-628-4357-5/.
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Geluk, Christiane Anneliese. "Coronary risk stratification from PREVEND to the prevention of coronary events /." [S.l. : Groningen : s.n. ; University Library of Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/305742574.
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Perera, Shyam Divaka. "The coronary collateral circulation in the setting of percutaneous coronary intervention." Thesis, King's College London (University of London), 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444572.
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Carrillo, Suárez Xavier. "Diagnóstico y pronóstico de la cardiopatía isquémica asociada al consumo de cocaína." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/457526.
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Introducción: El consumo recreacional de cocaína ha aumentado en los últimos años en Europa, siendo España uno de los principales países consumidores de cocaína. La cocaína tiene múltiples efectos sobre el sistema cardiovascular, entre ellos ser desencadenante de un Síndrome Coronario Agudo (SCA).
Método: Estudio observacional prospectivo, entre 2001 y 2014, en pacientes con SCA menores de 50 años que ingresaban en la unidad coronaria. Se realizó una anamnesis específica del consumo de cocaína y una determinación de los metabolitos de cocaína en orina. Nuestra hipótesis de trabajo fue “El consumo reciente de cocaína asociado a un síndrome coronario agudo (SCA-ACC) tiene un impacto pronóstico deletéreo a corto y largo plazo respecto al SCA no debido a cocaína”. Se definió el SCA-ACC en aquellos pacientes con SCA y determinación positiva de metabolitos de cocaína en orina o consumo reciente de cocaína por anamnesis.
Resultados: Se incluyeron 1002 pacientes menores de 50 años con SCA. El 15.1% reconocían haber consumido cocaína alguna vez en su vida (el 41.7% eran exconsumidores, el 33.1% eran consumidores ocasionales y el 25.2% eran consumidores habituales de cocaína). Observamos un incremento en la prevalencia de consumo de cocaína des del 6.6% en 2002 hasta un pico del 21.7% y 20.5% en 2008 y 2009. Obtuvimos una determinación de metabolitos en orina en 864 pacientes (86.2%), siendo positiva en 52 (6%). Presentaban un SCA-ACC 59 pacientes (6.8%). Los pacientes con antecedentes de consumo de cocaína presentaban un mayor consumo de tóxicos además de cocaína como el tabaco, el alcohol y las otras drogas. En los pacientes con SCA-ACC observamos una mayor frecuencia de presentación como SCA con elevación del segmento ST (SCAEST). Los pacientes con SCA-ACC recibieron menos tratamiento con betabloqueantes en la fase aguda (40.7 contra 78.1%, p<0.001) y también al alta (59.6 contra 84.2%, p<0.001). Sin diferencias en los tratamientos de reperfusión realizados a los pacientes con SCAEST, únicamente una menor utilización de stents farmacoactivos (17.6 contra 34.5%, p=0.043). Durante la fase hospitalaria los SCA-ACC presentaron mayores complicaciones hospitalarias como la taquicardia ventricular (16.9 contra 4.7%, p<0.001), shock cardiogénico (6.8 contra 2.2%,p=0.032) y trastorno agudo de la conducción intraventricular (6.8 contra 1.5%,p=0.004) y una tendencia a mayor mortalidad hospitalaria (3.4 contra 1.0,p=0.097).
El seguimiento realizado al 92.4% de los pacientes (mediana de 2381 días) observamos una mayor mortalidad en los pacientes con SCA-ACC (12.3 contra 5%,p=0.020) y también mortalidad cardiaca (7 contra 1.2%,p<0.001). El evento combinado de muerte, infarto o revascularización (MACE) también fue superior en SCA-ACC (35.1 contra 18.8%,p=0.003). El análisis multivariado de supervivencia por Coxx ajustado por la clasificación de killip y el tratamiento al alta presentó una HR de 2.126 ([IC 0.926-4.881],p=0.075) para mortalidad global, 4.038 ([IC 1.151-14.168],p=0.029) para mortalidad cardiaca y 2.015 ([IC 1.247-3.255],p=0.004) para MACE.
Conclusiones: El tratamiento administrado en los pacientes con SCA-ACC es diferente al SCA-NACC, utilizando una menor proporción de fármacos betabloqueantes, así como de stents liberadores de fármaco en los procedimientos de intervencionismo coronario. Los pacientes con SCA-ACC tienen una peor evolución al seguimiento que los pacientes con SCA-NACC con una mayor incidencia de trombosis del stent, una mayor mortalidad (global y especialmente la de causa cardiaca) y tienen mayores eventos isquémicos, principalmente el infarto de miocardio. En nuestro medio se confirma nuestra hipótesis y los pacientes con síndrome coronario agudo asociado al consumo reciente de cocaína presentan un peor pronostico hospitalario con mayor numero de complicaciones hospitalarias y un peor pronostico a largo plazo con mayor mortalidad y infarto de miocardio al seguimiento.Background: Recreational cocaine consumption in European countries has increased in recent years, and Spain is one of the main cocaine-using country in Europe. Cocaine has several effects on the cardiovascular system, being a trigger for Acute Coronary Syndrome (ACS). Methods: A prospective observational study was conducted between 2001 and 2014 in patients admitted to our coronary unit younger than 50 years old who suffered from an ACS. A detailed history of cocaine use and a determination of the metabolites of cocaine in urine were performed. Our working hypothesis was "Recent cocaine use associated with an acute coronary syndrome (ACS-ACC) has a deleterious short- and long-term prognostic impact on ACS not due to cocaine." Recent cocaine use associated with ACS (ACS-ACC) was defined as positive determination of cocaine metabolites in urine or admitting recent cocaine consumption prior to admission in the anamnesis in those patients who suffered an ACS. Results: 1002 patients younger than 50 years with ACS were included. 15.1% reported having consumed cocaine at least once in their lifetime (41.7% were former users, 33.1% occasional users and 25.2% current users). We observed an increase in prevalence of cocaine use from 6.6% in 2002 to a peak of 21.7% and 20.5% in 2008 and 2009. Determination of metabolites was obtained in 864 patients (86.2%), being positive in 52 (6%). A total of 59 patients (6.8%) presented a ACS-ACC. Patients with a history of cocaine use had a higher consumption of other substances, such as tobacco, alcohol, and other. Higher frequency of ACS with ST segment elevation was observed in cocaine users. The group of patients with ACS-ACC received less treatment with beta-blockers in the acute phase (40.7 vs 78.1%, p<0.001) and also at discharge (59.6 vs 84.2%, p<0.001). Differences in reperfusion treatments for patients with ACS-ACS were not observed in spite of a lower lower use of drug-eluting stents (17.6 vs 34.5%, p=0.043). During hospitalization, patients with ACS-ACC presented higher complications such as ventricular tachycardia (16.9 vs 4.7%, p<0.001), cardiogenic shock (6.8% vs 2.2%, p=0.032) and acute intraventricular conduction abnormalities (6.8 vs 1.5%,p=0.004) as well as a trend towards a higher hospital mortality (3.4 vs 1.0, p=0.097). Higher mortality in patients with ACS-ACC was observed (12.3% vs 5%, p=0.020) and also cardiac mortality (7% vs. 1.2%, p<0.001). The combined event of death, infarction or revascularization (MACE) was also higher in ACS-ACC (35.1 vs 18.8%, p = 0.003). Coxx survival multivariate analysis adjusted for killip classification and treatment at discharge showed a HR of 2.126 ([IC 0.926-4.881], p = 0.075) for overall mortality, 4,038 ([1,151-14,168], p = 0.029) for cardiac mortality and 2.015 ([1.247-3.255], p=0.004) for MACE. Conclusions: The treatment given in patients with ACS-ACC differs from patients with ACS-NACC, with lower proportion of beta-blocking drugs being used during admission and at discharge as well as a higher implantation of drug-eluting stents in coronary intervention procedures. Patients with ACS-ACC have a worse outcome at follow-up than patients with ACS-NACC with more incidence of stent thrombosis, higher mortality (overall and especially cardiac cause) and higher ischemic events, mainly miocardial infarction. Our hypothesis is confirmed in our setting, and patients with acute coronary syndrome associated with recent cocaine use have worse hospital prognosis with greater number of hospital complications, worse long-term prognosis with higher mortality and myocardial infarction at follow-up.
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Kim, Song-Jung. "Hypoxemia Attenuates Coronary Autoregulation." Thesis, University of North Texas, 1989. https://digital.library.unt.edu/ark:/67531/metadc500734/.
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The effect of hypoxemia on coronary autoregulation was investigated in nine anesthetized, open-chest dogs. The anterior descending coronary artery (LAD) was cannulated and perfused with normoxic arterial blood and with moderately hypoxic blood (0₂ content = 10 + 1 ml 0₂ /dl). LAD blood flow was measured as perfusion pressure was varied from 140 to 40 mmHg. At perfusion pressures at and above 40 mmHg, hypoxemia significantly increased LAD flow. During normoxia, the autoregulatory closed-loop gain (Gc) was significantly greater than zero at perfusion pressures from 60 to 120 mmHg. During hypoxemia, Gc was greater than zero only at perfusion pressures from 80 to 100 mmHg. During hypoxemia, LAD blood flow increased sufficiently to maintain oxygen delivery and consumption constant, but the range and potency of autoregulation was attenuated.
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Obaid, Daniel Rhys. "Coronary atherosclerotic plaque imaging." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608243.
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Holt, Jim, and Gregg Mitchell. "Coronary Artery Disease KSA." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/6457.
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Thompson, Mary. "Coronary effects of endothelins." Thesis, University of Bath, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296580.
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Finniss, Mathew Christopher MD, Nimrat MD Bains, and Shelby DO Shamas. "Sumatriptan Induced Coronary Vasospasm." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/179.
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Migraines are recurrent debilitating headaches that predominately afflict young women. The pathophysiology of migraines is still not well understood but is related to neurovascular dysfunction. Meningeal blood vessel dilation, extravasation of pro-inflammatory cytokines and activation of trigeminal afferent neurons promote migraine generation.
Serotonin (5-HT) is an endogenous vasoactive peptide with diverse physiology. In meningeal blood vessels, serotonin causes vasoconstriction, however in coronary arteries, serotonin causes both vasodilation and vasoconstriction. In diseased coronary arteries, with impaired endothelial function, vasoconstriction predominates.
Selective meningeal blood vessel serotonin agonists, termed ‘triptans’, have become the therapy of choice for migraine headaches. However, due to their constrictive effects on the coronary vasculature, triptans are not recommend in patients with known coronary artery disease, patients with greater than one coronary artery risk factor or patients with atherosclerotic cardiovascular disease risk (ASCVD) greater than ten percent.
Triptan associated chest pain is a well-known phenomenon. Age, hypertension, dyspepsia, and Raynauds phenomenon are associated with triptan associated chest pain. Hypertension is the strongest risk factor for triptan associated chest pain in males. Although triptan associated chest pain is assumed to be cardiovascular due to its constrictive effect on the coronary vasculature, only a few cases of myocardial infarction, with documented ST elevation and/or troponin elevation, have been reported.
Herein we report the case of a male patient with inferolateral ST elevation myocardial infarction, within minutes of receiving subcutaneous sumatriptan for migraine headache. The patient had a normal echocardiogram and electrocardiogram prior to sumatriptan use, and a normal cardiac catheterization afterwards.
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Maslenkova-Gerbaud, Tatiana. "Die Provokationsteste mit Ergonovin und Methergin zum Nachweis koronarer Hyperreagibilität." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2000. http://dx.doi.org/10.18452/14563.
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Ziel: Methergin und Ergonovin werden in der Literatur als gleichwertige Substanzen zum Nachweis koronarer Hyperreagibilität (VSAP) während der Koronarangiographie betrachtet. Ziel dieser Studie ist 1) die Sensitivität der 2 Substanzen zu vergleichen und 2) ihren vasokonstriktorischen Effekt auf menschliche Koronararterien quantitativ zu analysieren. Methoden: 1) Für die Ermittlung der Sensitivität wurden 340 Patienten ohne Koronararterienstenosen >50% mittels Provokations-Test untersucht. Davon 182 mit Ergonovin und 158 mit Methergin. Es erfolgten Subgruppenanalysen nach Geschlecht, Alter, Koronarrisikofaktoren und klinischer Symptomatik. 2) Die quantitative spastische Wirksamkeit der 2 Testsubstanzen wurde verglichen anhand der Analyse der Reaktion der Segmente mit diffusem Spasmus, der Segmente mit lokalem Spasmus und der benachbarten normalen Segmente aus Koronarangiographien von Patienten mit nachgewiesener VSAP. Das Testkollektiv besteht aus 17 Patienten. Bei 10 wurde der Spasmus mit Ergonovin ausgelöst, bei 7 mit Methergin. Die Kontrollgruppe bestand aus 18 Patienten (10 untersucht mit Ergonovin, 8 mit Methergin). Es erfolgten Subgruppenanalysen nach Geschlecht und Gefäßgröße. Resultate: 1) Die Sensitivität des Ergonovin-Tests (18%) ist signifikant (pObjects: Methergine and Ergonovine are described in literature as similar for recognizing coronary hyperreagibility (VSAP) during coronary angiography. The purpose of this study is 1) to compare the sensitivity of both the substances and 2) to analyze the quantitative effect of arterial vasocontraction in human coronary arteries. Methods: 1) 340 patients without coronary stenosis where examined by provocation-tests to ascertain the sensitivity. 182 of them were treated with Ergonovine and 158 with Methergine followed by analysis of subgroupspecifications like gender, age, coronary risk factors and clinical symptoms. 2) The quantitative spasmodic effects of both testsubstabces were compared by means of analyses of the reaction of the segments with diffuse spasm also of the segments with local spasm and the near by localised normal segments from coronary angiographys from patients with variant angina (VSAP). 17 patients were in the testcollective. In 10 the spasm was triggered by Ergonovine, in 7 with Methergine. 18 patients were in the controlgroup (10 examined on Ergonovine, 8 on Methergine). The analysis of subgroups were carried out regarding gender and vasculardiameter. Results: 1) The sensitivity of the Ergonovine-tests (18%) is significantly (p
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Sitt, Wing-hung Edward, and 薛穎雄. "Is the validity of non-invasive computerized tomography coronary angiography equivalent to invasive coronary angiography for theevaluation of coronary artery disease." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39724578.
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Kurbaan, Arvinder Singh. "The utility of coronary scoring systems in assessing the influence of immediate post revascularisation coronary disease and its interplay with coronary restenosis on the one year outcome of coronary revascularisation." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343803.
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Patel, Niket. "Coronary microcirculatory physiology following primary percutaneous coronary intervention for ST-elevation myocardial infarction." Thesis, St George's, University of London, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.703275.
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Microvascular no-reflow occurs in greater than 50% of patients following primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) and, although it adversely affects outcomes, it is poorly understood. The aim of this thesis was to study the physiology of the microcirculation in patients following STEM I. We studied the microcirculatory physiology using thermodilution and Doppler flow wire techniques. The infarct-related artery was studied at PPCI and 24-hours postPPCI. Zero flow pressure (pzfL hyperaemic myocardial resistance (hMR), index of microcirculatory resistance (IMR) and coronary flow reserve (CFR) were calculated. Furthermore, a novel parameter 'hyperaemic backward expansion wave ratio' (hBEW ratio) was computed using WIA as the ratio of hyperaemic and resting BEW wave intensity. The extent of myocardial injury was determined by contrast cardiac magnetic resonance (CMR) at day two and 6 months post-PPCI. pzf was found to be superior to IMR and hMR in predicting infarction size following PPCI. Furthermore, pzf correlated significantly with transmurality of infarction, salvage index and 6-month ejection fraction. Using a cut of pzf ~42mmHg allowed the identification of a cohort of patients with adverse clinical, angiographic and CMR features of infarction. Secondly, hBEW ratio was significantly smaller at PPCI compared to 24h post-PPCI and in a control cohort of patients undergoing stable PCI. This was driven by a similar resting BEW between the cohorts, but a significantly smaller hyperaemic response was observed following PPCI and, to a lesser extent, at 24h post-PPCI compared to patients having stable PCI. Furthermore, there was a significant relationship between hBEW ratio and CFR. pzf may provide important prognostic information at the time of PPCI. Secondly, the affect of hyperaemia on BEW intensity is attenuated following STEMI suggesting muted microvascular function and hBEW ratio offers mechanistic insight based on computational phasic fluid dynamics regarding poor flow reserve.
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Chaichana, Thanapong. "Haemodynamic evaluation of coronary artery plaques : prediction of coronary atherosclerosis and disease progression." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/1233.
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Coronary artery disease is the leading cause of death in advanced countries. Coronary artery disease tends to develop at locations where disturbed flow patterns occur, such as the left coronary artery. Haemodynamic change is believed to play an important role in the pathogenesis of coronary artery disease. This study was conducted to analyse the haemodynamic variations in the left coronary artery, with normal and diseased conditions, based on idealised human left coronary artery models and realistic reconstructed left coronary geometries. Computational fluid dynamics analysis was performed, to replicate the actual physiological conditions that reflect the in vivo cardiac haemodynamics with high resolution CT images. The wall shear stress, wall shear stress gradient, velocity flow patterns, pressure gradient, wall pressure, wall pressure gradient, wall pressure stress gradient, were calculated though in idealised but near realistic left coronary geometries during the cardiac pulsatile cycles. This novel research was performed in four stages, with Stage 1 studying the correlation between bifurcation angle and subsequent haemodynamic effects; Stage 2 focused on the position of plaques in the left coronary artery and corresponding haemodynamic variations based on realistic models; Stage 3 investigated the impact of plaques on coronary side branches based on realistic models. Stage 4 analysed individual patients with the bifurcation stenosis based on CT images.Normal coronary artery geometries were generated to investigate the haemodynamic variations of various angulations of the left coronary artery, based on idealised and actual coronary artery models. Eight idealised left coronary artery models were generated, with inclusion of different coronary angulations, namely, 120°, 105°, 90°, 75°, 60°, 45°, 30° and 15°. Four realistic left coronary artery geometries were reconstructed, based on selected patient's data, with angulations ranging from wide angulations of 110° and 120° to narrow angulations of 73° and 58°. There were twelve left coronary artery models in total which consisted of left main stem, left anterior descending and left circumflex branches. Haemodynamic analysis showed that disturbed flow patterns were observed in both idealised and realistic left coronary geometries with wider angles. Wall pressure was found to reduce when the flow changed from the left main stem to the bifurcated locations. A low wall shear stress gradient was revealed at left main bifurcations in models with wide angulations. There is a direct correlation between coronary angulations and subsequent haemodynamic changes, based on realistic and idealised geometries.Diseased coronary geometry was used to study the haemodynamic changes surrounding the bifurcation plaques based on patient’s data. High resolution CT images of the coronary plaques were used to locate and generate the position of actual plaques, which was combined with the reconstructed left coronary disease geometry. Coronary plaques were replicated and located at the left main stem and the left anterior descending to produce at least 60% coronary stenosis. Computational fluid dynamic analysis was used to investigate the haemodynamic effects with and without the presence of coronary plaques. Our results revealed that the highest pressure gradients were observed in stenotic locations caused by the coronary plaques. Low flow velocity regions were found at post-stenotic locations in the left bifurcation, left anterior descending, and left circumflex. Wall shear stress at the plaque locations was similar between the non-Newtonian and Newtonian models, although more details were observed with non-Newtonian model. There is a direct correlation between coronary plaques and subsequent haemodynamic changes, based on the simulation of plaques in the realistic left coronary geometries.Coronary artery disease with their side branches was used to analyse the change of haemodynamic factors surrounding bifurcation plaques to characterise the effect of disturbed flow to their side branches. Coronary plaques were located at the left main bifurcation, which is composed of the left main stem and the left anterior descending to generate >50% narrowing of the coronary lumen. Haemodynamic parameters were compared in the left coronary artery models, with and without the presence of plaques. The analysis demonstrated that wall shear stress decreased while wall pressure stress gradient was increased in coronary side branches due to the presence of plaques. There is a direct relationship between coronary plaques and subsequent haemodynamic changes based on the bifurcation plaques located in the realistic coronary geometries.Patient-specific models with coronary disease were used to analyse the haemodynamic variations surrounding the stenotic locations. Three sample patients with left coronary artery disease were chosen based on CT data. Coronary plaques were shown at the left anterior descending and left circumflex branches with more than 50% lumen narrowing. Wall shear stress and blood flow changes in the left coronary artery disease were calculated during cardiac pulsatile cycles. Our results showed that wall shear stress was found to increase at the stenotic regions and decrease at pre- and post-plaque regions, while the disturbed flow regions was found at post-plaque location. There is a direct effect bifurcation plaque on the changes of blood flow and wall shear stress, based on the realistic coronary disease geometries.In summary, the results of this project show that coronary angulation is directly related to haemodynamic changes, resulting in the formation of atherosclerosis, leading to coronary artery disease. Presence of coronary plaques impacts the haemodynamic changes to both the left main coronary artery, and side branches. Computational fluid dynamic analysis of realistic normal and diseased coronary models improves our understanding of the pathogenesis of coronary artery disease. Further studies are needed to correlate the haemodynamic changes in the presence of plaques with clinical outcomes in patients with suspected coronary artery disease.
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Sitt, Wing-hung Edward. "Is the validity of non-invasive computerized tomography coronary angiography equivalent to invasive coronary angiography for the evaluation of coronary artery disease." View the Table of Contents & Abstract, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38479606.
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Mehilli, Julinda. "Have women with coronary artery disease a higher risk than men after coronary stenting?" [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965479668.
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Pearson, Ian Russell. "Markers of risk in patients with acute coronary syndrome treated by percutaneous coronary intervention." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/13563/.
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Background - The clinical diagnosis and categorisation of Acute Coronary Syndrome (ACS) has changed repeatedly over the last decade as have routine treatment strategies. Hypothesis - that adverse clinical events following PCI, may be predicted from the identification of markers of risk at the time of PCI. Methods - Informed consent was obtained from 968 patients fulfilling detailed inclusion and exclusion criteria surrounding a diagnosis of ACS requiring PCI. Standard medical ACS care was provided. PCI operators, techniques, methods and any decision to treat followed usual practice. Data collection took place at the time of intervention and during active follow-up. Blood sample were collected at baseline and 4 and 12 hours after PCI, being processed and refrigerated. Platelet function was assessed at baseline using the VerifyNow test method. Results – Data collection was over a median follow-up time of 3.56 years. Patients were aged 27 to 90 years and a majority were male (75%). Angiographic complications occurred in 13.2% and total complications in 17.1%. A majority (844; 86%) had neither restenosis nor subsequent unplanned revascularization. Recurrent ACS was 6.7% for year 1 and 1.8% additionally for each year thereafter. Stent thrombosis was observed in 18 (1.8%) cases. Bleeding occurred in 9% across the entire follow-up period, being greatest in the first 12 months. Platelet reactivity was highly variable and optimal with regard to outcome in the range of 179 to 243 (Platelet Reactivity Units PRU). Cardiac biomarkers were commonly elevated after PCI but procedural MI was very rare. H-FABP at baseline was strongly predictive of outcome. Conclusion – Adverse clinical events following PCI, such as stent thrombosis, bleeding and in-stent restenosis, may be predicted from the identification of markers of risk at the time of PCI, particularly by the use of risk scores, platelet function testing and measuring biomarker levels.
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Lee, Eunyoung. "An electrocardiographic and acoustic cardiographic study of acute coronary occlusion during percutaneous coronary intervention." Diss., Search in ProQuest Dissertations & Theses. UC Only, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3318518.
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Jönsson, Anders. "Surgical treatment of left main coronary artery stenosis /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-736-7/.
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El, Gendi Hossam Salah. "Platelet activation during coronary intervention." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271167.
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Bjessmo, Staffan. "Surgery for acute coronary syndromes /." Stockholm, 2000.
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Sorop, Oana Emilia. "Mechanosensitivity of isolated coronary arterioles." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/74810.
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Kapur, Akhil. "Coronary artery revascularisation in diabetes." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504904.
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Brouilette, Scott Wayne. "Telomeres and coronary heart disease." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/29899.
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Using mean telomere length as a marker of biological age, I show that: 1. Subjects with premature myocardial infarction (MI) have significantly shorter telomeres than age-sex matched, healthy, controls. The mean telomere length in MI subjects was similar to controls almost 11 years older. 2. Healthy young adult children of families with a strong history of premature MI have shorter telomeres than age matched children of families without such a history. 3. Shorter telomere lengths are associated with increase risk of subsequent CHD events in a prospective study. This analysis was carried out on samples collected in the West of Scotland Coronary Prevention Study (WOSCOPS). This randomised blinded trial was designated to examine the benefits of statin treatment on preventing CHD and showed a 30% reduction of events in those treated with pravastatin. Interestingly, my analysis showed that this benefit of statin is only seen in those subjects at higher risk of CHD based on their telomere length.;As the final part of the thesis I carried out a quantitative linkage trait (QTL) analysis in sib-pairs in an attempt to identify genetic loci regulating telomere length. I report the mapping of a major QTL on chromosome 12 that determines almost 50% of the inter-individual variation in mean telomere length.;These findings support a novel "telomere" hypothesis of CHD. They indicate that telomere biology is intimately linked to the genetic aetiology and pathogenesis of CHD. Specifically, the findings suggest that (i) those individuals born with shorter telomeres may be at increased risk of CHD (ii) rather than individual genes, a more global structural property of the genetic material may explain the familial basis of CHD (iii) variation in telomere length may explain, in part, the variable age of onset of CHD. The findings provide several new avenues for future research.
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Vorobtsova, Natalya. "Computational model of coronary tortuosity." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/51267.
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Coronary tortuosity is the abnormal curving and twisting of the coronary arteries. Although the phenomenon of coronary tortuosity is frequently encountered by cardiologists its clinical significance is unclear. It is known that coronary tortuosity has significant influence on the hemodynamics inside the coronary arteries, but it is difficult to draw definite conclusions due to the lack of patient-specific studies and an absence of a clear definition of tortuosity.
In this work, in order to investigate a relation of coronary tortuosity to such diseases as atherosclerosis, ischemia, and angina, a numerical investigation of coronary tortuosity was performed. First, we studied a correlation between a degree of tortuosity and flow parameters in three simplified vessels with curvature and zero torsion. Next, a statistical analysis based on flow calculations of 23 patient-based real tortuous arteries was performed in order to investigate a correlation between tortuosity and flow parameters, such as pressure drop, wall shear stress distribution, and a strength of helical flow, represented by a helicity intensity, and concomitant risks.
Results of both idealized and patient-specific studies indicate that a risk of perfusion defects grows with an increased degree of tortuosity due to an increased pressure drop downstream an artery. According to the results of the patient-specific study, a risk of atherosclerosis decreases in more tortuous arteries - a result different from an outcome of the idealized study of arteries with zero torsion. Consequently, a modeling of coronary tortuosity should take into account all aspects of tortuosity including a heart shape that introduces additional torsion to arteries. Moreover, strength of a helical flow was shown to depend strongly on a degree of tortuosity and affect flow alterations and accompanying risks of developing atherosclerosis and perfusion defects. A corresponding quantity, helicity intensity, might have a potential to be implemented in future studies as a universal single parameter to describe tortuosity and assess congruent impact on the health of a patient.Master of Science
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Stancell-Smith, Gwendolyn Yvonne. "Women and Coronary Artery Disease." ScholarWorks, 2017. https://scholarworks.waldenu.edu/dissertations/3415.
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Heart disease, including coronary artery disease, affects approximately 42 million women in the United States. Many of those affected are not aware they have the condition. Contributing to the problem is the fact that women are more likely than men to be misdiagnosed and undertreated for heart disease. Morbidity and mortality are high in women affected by heart disease, making the problem important to address. The purpose of this project was to understand the coronary artery or heart disease risk and the treatment for the condition provided for 31 participants at a cardiology service in the Northeast U.S. The project question focused on understanding how coronary artery disease manifest in women and the gender differences in treatment for men and women. A descriptive case design was used by gathering data from patient risk profiles and treatments. Participants were males and females aged between 30 and 80. Qualitative data were obtained through cardiology staff interviews and existing literature. The data were subjected to a content analysis to identify emergent themes. Findings indicated that the women experienced different cardiac symptoms to men, and these differences translated to misdiagnosis and resulting treatment ineffectiveness. This project contributes to social change through raising awareness of the gender differences in heart disease presentation so that providers can recognize and treat the condition effectively.
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Taraboanta, Catalin. "Impact of family history of premature coronary disease on carotid ultrasound and coronary calcium findings." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/721.
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First degree relatives (FDRs) of subjects with early onset of coronary heart disease (CHD) have higher risk of developing cardiovascular disease. We verified early CHD by angiography in the index patients and extensively phenotyped their FDRs to investigate the relationship of traditional and non-traditional cardiovascular risk factors to carotid ultrasound and coronary calcium scoring findings.
B-mode carotid ultrasound was used to assess the combined intima-media thickness and plaque burden in 111 FDRs. The biochemical and anthropometrical characteristics of the FDRs were compared with those of healthy controls matched for sex, age, ethnicity and BMI. Odds ratios indicate that FDRs are more likely to have positive carotid ultrasound findings compared to controls; 2.23 (95% CI 1.14 – 4.37) for intima-media thickness and 2.3 (95% CI 1.22 - 4.35) for average total thickness. In multivariate analysis positive carotid ultrasound findings were higher in FDRs independent of age, gender, total cholesterol over HDL-c ratio, systolic blood pressure and smoking but not homocysteine which had higher values in FDRs compared to controls. In conclusion FDRs of patients with angiographically confirmed CHD have higher burden of subclinical atherosclerosis even when considered in the context of traditional risk factors.
Coronary artery calcium scoring (CAC), assessed by 64-slice multi-detector computed tomography (MDCT), was used to assess burden of subclinical atherosclerosis in 57 FDRs compared to controls. FDRs have a two-fold increase in risk of having CAC positive findings; odds ratios for the 75th percentile was 1.96 (95%CI 1.04 – 3.67, p<0.05) while for the 90th percentile odds ratio was 2.59 (95% 1.232 – 5.473, p<0.05). In summary, the risk of significant CAC findings, measured by 64-slice MDCT, is two-fold higher in FDRs than controls. These findings correlate highly with carotid ultrasound findings in the same cohort. Different thresholds for CAC may be appropriate when assessing male versus female FDRs.
Together increased carotid ultrasound findings and CAC scoring results in FDRs of patients with validated early onset of CHD suggest these imaging techniques as potentially useful tools in cardiovascular risk assessment that will go above and beyond the current diagnostic algorithms.
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Starkhammar, Johansson Carin. "Periodontitis and coronary artery disease : Studies on the association between periodontitis and coronary artery disease." Doctoral thesis, Linköpings universitet, Kardiologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-86213.
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Periodontitis and coronary artery disease (CAD) are highly prevalent in Sweden’s population; both diseases have complicated pathogeneses and clinical manifestations due to immune-system triggered inflammation. Research in recent years reported that inflammation is a significant active participant in many chronic diseases. The literature described a CAD-periodontitis association, but underlying mechanisms are not fully understood. It is important to acquire knowledge about how periodontitis might influence CAD, which is one of the major causes of illness and death in western countries. Because periodontitis can be treated, this knowledge, when complemented with more knowledge about the CAD-periodontitis association, could lead to CAD prevention. The overall aim of studies reported in this thesis were to investigate the CAD-periodontitis association, and specifically, to: (i) compare periodontal conditions in patients with CAD and subjects without a history of CAD; (ii) study whether or not periodontal status influences outcomes in known CAD over an 8-year period; (iii) study whether or not concentrations and biological activity of hepatocyte growth factor (HGF) in serum from patients with severe CAD are different – depending on whether or not the subjects had periodontitis; and (iv) study concentrations and biological activity of hepatocyte growth factor in serum, saliva, and gingival crevicular fluid in healthy subjects with or without periodontitis. Here is a brief summary: In study I, 161 patients with CAD and 162 controls were compared regarding periodontal disease prevalence and severity. CAD patients had significant coronary stenosis and underwent percutaneous coronary intervention (PCI) or coronary artery by-pass grafts (CABG). Healthy controls were recruited from Sweden’s population database. Twenty-five per cent of the CAD patients had severe periodontitis, compared to 8% of the controls. In a multiple logistic regression analysis (controlled for age and smoking), severe periodontitis indicated an odds ratio of 5.74 (2.07–15.90) for CAD. Study II: Periodontal status was re-examined in 126 CAD patients and 121 controls from the initial sample after 8 years. Periodontal status at baseline was analysed and related to CAD endpoints (i.e., myocardial infarction, new PCI or CABG or death due to CAD) recorded from patients’ medical records and from the death index maintained by the National Board of Health and Welfare. The difference in periodontitis prevalence and severity between the two groups remained unchanged during the 8-year follow up. No significant differences were found regarding CAD endpoints during follow-up in relation to baseline periodontal status in the CAD-patient group. In study III, higher HGF serum concentrations (p<0.001) were found in CAD patients, compared to healthy blood donors, which reflects chronic inflammation. In CAD patients without periodontitis, HGF concentrations increased significantly 24 hours after PCI – in parallel with increased HGF biological activity. In CAD patients with periodontitis, only small fluctuations were seen in HGF values, i.e., concentration and biological activity. HGF biological activity was temporarily elevated after PCI but only in patients without periodontitis. Thus chronic inflammation related to periodontitis might reduce HGF biological activity. In study IV, HGF concentration and biological activity in saliva, in gingival crevicular fluid (GCF), and serum were compared between 30 generally healthy subjects with severe untreated periodontitis and 30 healthy subjects without periodontitis. Compared to periodontally healthy controls, periodontal patients showed higher HGF concentrations in saliva p<0.001, gingival crevicular fluid p<0.0001, and in serum p<0.001. HGF biological activity (measured as the binding affinity to its HSPG and c-MET receptors) was significantly reduced in saliva (p<0.0001) and GCF samples (p<0.0001 for HSPG and p<0.01 for c-MET) from periodontitis patients. The only significant difference in serum samples was an increases in c-MET binding three minutes after subgingival debridement in periodontitis patients (p<0.05), which might reflect that patients had active bursts of periodontitis. In conclusion, CAD patients more often showed severe periodontitis but there were no differences in CAD endpoints during the eight-year follow-up in relation to baseline periodontal status. Periodontitis seems to influence HGF concentration and biological activity in CAD patients, but studies on factors that cause lower HGF biological activity are necessary – to find out if periodontal treatment influences HGF biological activity. Healthy periodontitis patients had higher HGF concentrations locally and systemically, but biological activity was reduced. This might indicate that periodontitis can influence wound healing and tissue repair in other body parts.The ISBN 987‐91‐7519‐748‐7 is incorrect. Correct ISBN is 978‐91‐7519‐748‐7.
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Dodd-o, Jeffrey M. (Jeffrey Michael). "The effects of coronary α₁-adrenergic stimulation on coronary blood flow and left ventricular function." Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc332773/.
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This study examines the α-adrenergic constrictor tone varies with intensity of exercise, the effects of coronary α1-adrenergic blockade on left ventricular contractile function and regional myocardial perfusion, and compares the effects of increasing coronary blood flow by removing α1-constrictor tone.
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Ohya, Masanobu. "Long-Term Outcomes After Stent Implantation for Left Main Coronary Artery (from the Multicenter Assessing Optimal Percutaneous Coronary Intervention for Left Main Coronary Artery Stenting Registry)." Kyoto University, 2018. http://hdl.handle.net/2433/235034.
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Good, Richard I. S. "Antiplatelet response to aspirin and clopidogrel in patients with coronary artery disease undergoing percutaneous coronary intervention." Thesis, University of Glasgow, 2014. http://theses.gla.ac.uk/4910/.
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Aspirin and clopidogrel are cornerstone therapies in cardiovascular disease. In particular, they are almost universally prescribed in patients undergoing percutaneous coronary intervention (PCI). Evidence has emerged of a variation in the antiplatelet effects of aspirin and clopidogrel between individual patients with a suggestion of an increased risk of adverse cardiovascular events. However, the optimal method of measuring response to aspirin and clopidogrel remains uncertain. In light of this, the antiplatelet effects of both aspirin and clopidogrel were studied in patients with coronary artery disease, concentrating on patients undergoing PCI. Initially, a pilot study of 40 patients investigated the use of thromboxane B2 (TxB2), VerifyNow Aspirin, VerifyNow P2Y12, platelet fibrinogen binding and intra-platelet vasodilator-stimulated phosphoprotein levels (VASP-PRI) to measure response to aspirin and clopidogrel. This was followed by a larger study assessing aspirin and clopidogrel response in 323 patients attending for coronary angiography with a view to PCI. These patients were tested by measuring TxB2, VerifyNow P2Y12, VASP and whole blood impedance platelet aggregation (WBPA). The primary objective was to investigate whether measures of aspirin or clopidogrel efficacy predicted peri-procedural myocardial necrosis following PCI. In addition, a small series of 10 patients had aspirin and clopidogrel response measured following stent thrombosis. A wide variation in the antiplatelet effects of both aspirin and clopidogrel was found by all measures. Correlation between assays ranged from moderate to poor. Of particular interest, it was found that measurement of [TxB2] may facilitate the assessment of aspirin response in patients already taking clopidogrel. There was a high incidence of myocardial necrosis following coronary intervention assessed by elevation of troponin I. Only VerifyNow P2Y12 and VASP-PRI were associated with a significantly increased frequency of myocardial necrosis following PCI. The data of this thesis confirm a wide variation in response to aspirin and clopidogrel. Good response to clopidogrel was associated with reduced myocardial necrosis during PCI. TxB2 may be the best measure of aspirin response for patients taking both therapies. How these measures may be incorporated into clinical practice remains uncertain.
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Porter, Diana Creger. "HEALTH PERCEPTION, ANGINAL SYMPTOMS AND LIFE SATISFACTION AFTER CORONARY ARTERY BYPASS AND PRECUTANEOUS TRANSLUMINAL CORONARY ANGIOPLASTY." VCU Scholars Compass, 1986. https://scholarscompass.vcu.edu/etd/5248.
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The purpose of this descriptive correlational study was to gather data about the perceived health, anginal symptoms and life satisfaction in CABG and PTCA patients. The study explored the interrelationships among the variables and the differences between the two groups. The problem statement was:
1. How do patients perceive their own past, present and future health, level of anginal symptoms and life satisfaction after CABG and PTCA?
2. What are the interrelationships among perceived health, anginal symptoms and life satisfaction in CABG and PTCA patients.
The conceptual framework for this study was based on the social theory of symbolic interactionism and the nursing model of man-living-health (Parse, 1981). Perceived past, present and future health, anginal symptoms and life satisfaction were measured by the subject's self placement along 100 millimeter analog scales. Data were obtained in a 30 minute interview with each subject at the time of the patient's first follow-up visit to the physician's office four to eight weeks post procedure. Twenty-two percent of the patients (eight patients) who were eligible for inclusion were included in the study.
The means of the scores for perceived health, anginal symptoms and life satisfaction were calculated. The Kruskal-Wallis one-way analysis of variance statistic was used to detect statistically significant differences between the two groups of subjects, and graphs were constructed to illustrate the relationships among the variables. Demographic data were subjected to descriptive analysis by group.
The mean scores for the PTCA group were low for the past, only slightly higher for the present, and much higher for the future for all three variables. The mean scores for the CABG group were low for the past and much higher for the present for all three variables. The mean scores for the future were higher for anginal symptoms, but lower for health and life satisfaction for the CABG group. A significant difference was found between the two groups for perceived present health, anginal symptoms and life satisfaction. The mean scores for perceived health, anginal symptoms and life satisfaction assumed a similar curve on a line graph for each group, suggesting a correlation between the variables within the group.
Implications for nursing practice apply at primary and secondary levels of prevention. On the primary level, information obtained in descriptive research aimed at identifying commonly occurring perceptions in the CABG and PTCA patient would allow the nurse to begin intervention in the pre-procedure period by clarifying misconceptions and initiating accurate pre-procedure instruction. On the secondary level of prevention, the nurse can begin clarifying these commonly occurring misconceptions early in the recovery period in an attempt to encourage health-promoting behavior choices based on realistic expectations by the patient. Implications for nursing research and education were related to the addition of new information regarding the perceptions of the CABG and PTCA patient.
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Toyota, Toshiaki. "Ad-hoc Versus Non-ad-hoc Percutaneous Coronary Intervention Strategies In Patients with Stable Coronary Artery Disease." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225508.
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Ramaiola, Ilaria. "Thrombus composition in acute coronary syndrome." Doctoral thesis, Universitat Pompeu Fabra, 2015. http://hdl.handle.net/10803/456681.
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Atherothrombosis and, specifically intracoronary thrombosis is a major cause of acute coronary syndromes (ACS) and consequently of morbidity and mortality throughout the world. While management of acute ST-elevation myocardial infarction (STEMI) has dramatically improved over the last years, there is still a need to find thrombosis-related biomarkers for an early identification of ischemic processes and a better stratification of patients that have suffered an ACS. In fact, the ischemia time, defined as the time from the onset of symptoms to reperfusion, has been recently suggested as the “New Gold Standard for STEMI-Care”. This thesis mainly focuses on the protein composition of the occluding coronary thrombus, occurring both in the native coronary arteries and in the commonly implanted coronary stents. The study based on the proteomic analysis of coronary thrombi, obtained after percutaneous coronary intervention (PCI), has provided consistent evidence of the dynamic composition of the coronary thrombi in relation with the time of ischemia, and has resulted in the identification of novel biomarkers of potential use to be translated to the clinical practice. Furthermore, the comparison of native and in-stent-thrombosis has allowed the identification of proteins that might serve as interesting therapeutic targets to prevent thrombosis in patients who undergo PCI with stent-implantation.La enfermedad aterotrombotica y concretamente la trombosis intracoronaria es la mayor causa de los síndromes coronarios agudos (SCA), y consecuentemente de morbilidad y mortalidad en el mundo. El manejo de los pacientes con infarto agudo de miocardio con elevación del segmento ST ha mejorado considerablemente en los últimos años, a pesar de esto sigue siendo necesario encontrar biomarcadores para la detección temprana de los procesos isquémicos y que permitan una estratificación más eficiente de los pacientes que han sufrido un evento isquémico agudo. De hecho, el tiempo de isquemia, definido como el tiempo entre el inicio del dolor y la revascularización, ha sido recientemente definido como el parámetro fundamental en el tratamiento de los pacientes con STEMI. Este trabajo de tesis está enfocado a elucidar la composición proteica de los trombos coronarios oclusivos que se forman tanto en las arterias coronarias nativas como en aquellas con stent. El estudio se basa en el análisis proteómico de trombos coronarios en relación al tiempo de isquemia, con la finalidad de encontrar nuevos biomarcadores para trasladar a la práctica clínica. Además, la comparación entre trombos nativos y trombos desarrollados sobre el stent permite la identificación de proteínas diferenciales que podrían ser futuras dianas terapéuticas para prevenir la formación del trombo en pacientes sometidos a angioplastia coronaria transluminal percutánea (ACTP) con implantación de un stent coronario.
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Gilpin, Crystal Marie. "Cyclic Loading of Porcine Coronary Arteries." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6912.
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Atherosclerotic plaque caps are composed of a composite soft tissue material
that becomes subjected to cyclic loading under stenotic flow conditions.
The cyclic loading causes the plaque cap to fatigue and eventually fail. The
hypothesis of this work is that arteries and plaque caps may fatigue which may
be predicted by a stress vs. number of cycles (S-N) curve. The S-N curve has not
been determined for almost any biological soft tissue. The Specific Aim of the
thesis is to quantify an S-N curve for normal arterial soft tissue collected from
cyclic tension testing. Coronary arteries from porcine hearts will be tested as a
material that closely models the plaque cap in non-linear elastic behavior. The
S-N curve will be developed through failure testing with multiple cycles at
stresses between 0.5 and 5 MPa.
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Donnelly, Patrick Martin. "Computed tomography of the coronary arteries." Thesis, Queen's University Belfast, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446135.
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Williams, Rupert Philip Charles. "Coronary physiology of the stressed heart." Thesis, King's College London (University of London), 2016. https://kclpure.kcl.ac.uk/portal/en/theses/coronary-physiology-of-the-stressed-heart(a6f0e19d-b6fe-4ced-a37c-181d5266ae69).html.
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Background Highest rates of exertion related cardiac death occur during cold air inhalation (CAI): e.g. shovelling snow, but the pathophysiology is unclear. Coronary micro-vascular resistance (MVR) is the major factor regulating coronary blood flow and subsequent myocardial perfusion. Patients with significant coronary artery disease may be more prone to adverse events due to a reduced vasodilator reserve. Novel intracoronary wires, that simultaneously measure coronary artery pressure (Pd) and coronary blood flow (CBF) allow quantification of MVR, enabling physiological investigation of the effects of CAI during exercise. Study 1. hMR versus IMR at predicting microvascular dysfunction. We compared headto- head, the diagnostic accuracy of the two available invasive indices of MVR, Dopplerderived hyperaemic microvascular resistance (hMR) versus thermo-dilution-derived index of microcirculatory resistance (IMR), at predicting microvascular dysfunction. We then used the most accurate measure of MVR in Study 2. Study 2. Cold air with and without exercise on MVR in CAD patients. We explored the effects of CAI alone and during exercise on MVR and CBF in patients with significant coronary artery disease. Methods Study 1. 56 patients (61 ± 10 years) undergoing cardiac catheterisation for stable coronary artery disease or acute myocardial infarctions (AMI) were recruited. Simultaneous intracoronary pressure, Doppler flow velocity and thermodilution were carried out in 74 vessels without obstructive epicardial disease, at rest and during hyperaemia. In the absence of a gold-standard, the following three measures of microvascular dysfunction were used, using a pre-defined dichotomous threshold for each parameter: 1) Mean coronary flow reserve (CFRmean), defined as the average value of Doppler and thermodilution derived coronary flow reserve 2) Cardiac Magnetic Resonance (CMR) defined myocardial perfusion reserve index (MPRI) 3) CMR defined extensive microvascular obstruction (MVO). Study 2. 35 patients (62 ± 9 years) with significant coronary artery stenoses who were undergoing coronary angiography were allocated to 5 minutes of either: 1. CAI (-15oC), n=10 2. Exercise (Incremental supine ergometry), n=24 3. Exercise with CAI, n=13. (12 patients did both conditions 2. and 3., and for these patients the order was randomised). Forty seven datasets were obtained in total. We compared rest and peak measurements of Doppler-derived MVR (Pd/CBF) and CBF. We also used wave intensity analysis to identify waves that accelerate and decelerate CBF, and calculated the proportional contribution of accelerating waves as a coronary perfusion efficiency index. Results Study 1. hMR had better diagnostic accuracy than IMR to predict CFRmean (area under curve, (AUC) 0.82 versus 0.58, p < 0.001, sensitivity/specificity 77/77% versus 51/71%) and MPRI (AUC 0.85 versus 0.72, p=0.19, sensitivity/specificity 82/80% versus 64/75%). In AMI patients, the AUCs of hMR and IMR at predicting extensive MVO were 0.83 and 0.72 respectively (p=0.22, sensitivity/specificity 78/74% versus 44/91%). Study 2. MVR increased during CAI alone, whereas MVR decreased during exercise. Exercise with CAI was associated with less decrease in MVR. The increase in CBF was similarly less during exercise with CAI versus without. Coronary perfusion efficiency increased during exercise. However the addition of CAI during exercise abolished this. Conclusion Study 1. In our study cohort Doppler-derived hMR had superior diagnostic accuracy over IMR at predicting several invasive and non-invasive measures of microvascular function. This measure was therefore used to measure MVR in Study 2. Study 2. In CAD patients CAI substantially attenuated the reduction in MVR and the increase in CBF that normally occur during exercise. Moreover, while the heart has improved coronary perfusion efficiency during exercise, this may be attenuated when exercise is combined with CAI. This suggests that CAI during exercise may impede coronary vasodilatation and ventricular relaxation, rendering the heart more susceptible to ischaemia. Complementary studies (Studies 3 and 4) were performed in the absence of invasive measures of central and coronary haemodynamics to examine the differential effects of isometric and dynamic exercise (Study 3) and that of first and second exercise efforts (Study 4).
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Amrani, Mohamed. "Postischemic coronary flow and reperfusion injury." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307467.
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Danesh, John. "Chronic infection and coronary heart disease." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326020.
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Bakhai, Ameet. "Health Economics of Acute Coronary Syndromes." Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516979.
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Ahmed, Nabeel. "Platelet reactivity in coronary artery disease." Thesis, Imperial College London, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.530480.
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Roberts, Michael John Desmond. "Acute coronary syndromes : thrombolysis and reperfusion." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317451.
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Kounali, Daphne. "Early growth and coronary heart disease." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436926.
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Raphael, Claire. "Coronary flow abnormalities in hypertrophic cardiomyopathy." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/51512.
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Hypertrophic cardiomyopathy (HCM) affects 1 in 500 of the general population. Patients commonly suffer from angina, exhibit abnormal coronary flow patterns and have impaired myocardial perfusion. Wave intensity analysis (WIA) allows improved understanding of how myocardial mechanics result in impaired coronary flow. We used WIA to describe these mechanisms in HCM. We developed a new sequence for measurement of coronary flow velocity using cardiovascular magnetic resonance (CMR) and tested its utility for non-invasive coronary WIA. Patients with HCM had a lower coronary flow reserve than controls and 30% had systolic reversal of flow. During early systole, HCM patients had a much larger fractional backward compression wave compared to controls (38.2±11.1% versus 21.0±6.2%, p < 0.001). Patients with severe left ventricular outflow tract obstruction had a bisferiens pressure waveform resulting in an additional proximally originating deceleration wave during systole. These changes correlated with the severity of myocardial perfusion impairment. Perfusion abnormalities in HCM are therefore not simply a consequence of supply/demand mismatch or remodelling of the intra-myocardial blood vessels but represent a dynamic interaction with myocardial mechanics. We developed a retrospectively-gated breath-hold spiral phase velocity mapping sequence with high temporal resolution for measurement of flow velocity in the proximal coronary arteries using CMR and validated this against invasive measurement. CMR velocities were approximately 40% of the invasive values. Plots of MR velocities at any time point in the cardiac cycle against Doppler velocities in individual vessels showed a linear relationship with high R2 values (mean ± SD: 0.8± 0.1). Combination of the velocity data with pressure data derived from aortic distension produced the expected pattern of forward and backward compression and expansion waves seen in coronary arteries with comparable intra-study reproducibility to invasive WIA. Although only tested in small numbers, if validated this technique would expand the accessible patient population for WIA.