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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
361

Análise do grau de lesão obstrutiva coronária e sua correspondente parede miocárdica como fatores preditivos de perviedade e remodelamento da artéria radial na revascularização do miocárdio / Analysis of coronary obstruction and irrigated myocardial wall as predictive factors for patency and remodeling of radial artery grafts in coronary artery bypass surgery

Luciano Jannuzzi Carneiro 17 February 2009 (has links)
A artéria radial (AR) constitui valiosa opção de enxerto na revascularização do miocárdio (RM), desde a retomada de seu uso, nos anos 1990. O objetivo deste estudo foi avaliar perviedade e remodelamento dos enxertos de AR e sua relação com lesão obstrutiva pré-operatória e parede miocárdica revascularizada, observando-se também os enxertos de artéria torácica interna (ATI). CASUÍSTICA E MÉTODO: Entre 1994 e 2007, 3.964 pacientes foram operados com uso da AR, no InCor/HCFMUSP. Foram selecionados os reestudos angiográficos (12 meses) de 100 pacientes, sendo 11 deles reestudados em duas épocas diferentes. Em 92 pacientes foi utilizada a ATI. Foram determinados os diâmetros médios de AR e ATI, através do software CASS-II®. RESULTADOS: O tempo médio de reestudo foi de 70,53 ±33,18 meses. Em 82 casos (82,0%), a AR revascularizou uma única coronária, mais freqüentemente (50,83%) os ramos marginal esquerdo (ME) ou ventricular posterior (VP/CX). As obstruções pré-operatórias entre 90 e 99% foram as mais prevalentes (39,0%). A perviedade observada foi de 80 casos para AR (80,0%) e 80 para ATIE (86,96%). Houve correlação entre as maiores obstruções pré-operatórias e maior perviedade da AR (p=0,024). Os diâmetros médios dos enxertos foram de 2,302mm ±0,479 (AR) e 2,262mm ±0,409 (ATI). Observaram-se AR maiores do que a média (>2,30mm) nas obstruções pré-operatórias de 100%, em comparação com as demais (p=0,017). As AR que revascularizaram a parede lateral apresentaram os maiores diâmetros, em comparação às demais (p=0,04). Nos 11 pacientes com 2 reestudos, os diâmetros médios das AR foram de: 2,482mm ±0,424 (primeiro reestudo) e 2,599mm ±0,532 (segundo reestudo)(p=n/s). Para as ATIE, observaram-se: 2,308mm ±0,459 (primeiro reestudo) e 2,326mm ±0,531 (segundo reestudo) (p=n/s). No segundo reestudo, observou-se maior número de AR com diâmetros maiores, relacionados às obstruções entre 90-100% (p=0,013). A parede miocárdica revascularizada não interferiu nos diâmetros dos enxertos. CONCLUSÕES: A obstrução pré-operatória interfere na perviedade e nos diâmetros dos enxertos de AR, especialmente nas obstruções de 90% ou mais. A parede miocárdica revascularizada não interfere na perviedade da AR, porém interfere nos diâmetros dos enxertos. Foi observado remodelamento dos enxertos de AR, estando as obstruções mais graves relacionadas aos maiores aumentos de diâmetros dos enxertos comportamento semelhante às ATI. / The radial artery (RA) is an invaluable option for coronary artery bypass grafting (CABG), since its re-introduction in the late 1990 s.The objective of this study was to assess patency and remodeling of RA grafts regarding the interference of pre-operative coronary obstruction and grafted myocardial wall, also observing the internal thoracic artery grafts (ITA). METHODS: Between 1994 and 2007, 3,964 patients were operated with RA grafts, at Heart Institute, University of São Paulo, Brazil. Post-operative coronary angiographies (12 months)of 100 patients were obtained, including 11 patients with two post-op exams, at different periods. In 92 patients the ITA was also used.The grafts medium diameters were obtained using the CASS-II® software. RESULTS: Mean time of post-op angiography was 70,53 ±33,18 months. In 82 cases (82,0%) the RA grafted a single coronary, more frequently (50,83%) the left marginal (LM) or posterior ventricular (PV) branches. Pre-op obstructions between 90 and 99% were more prevalent (39,0%). Patency was of 80 cases for the RA (80,0%) and 80 cases for the ATI grafts (86,96%). There was a correlation between more severe pre-op obstructions and greater patency of the RA grafts (p=0,024). The mean diameters were 2,302mm ±0,479 (RA) and 2,262mm ±0,409 (ITA). RA diameters were above the mean value (>2,30mm) in pre-op obstructions of 100%, compared to the rest (p=0,017). The RA grafting the lateral wall showed the larger diameters, compared to the rest (p=0,04). For the 11 patients with 2 post-op angiographies, mean diameters of RA grafts were: 2,482mm ±0,424 (first) and 2,599mm ±0,532 (second)(p=n/s). For ITA grafts, mean diameters were: 2,308mm ±0,459 (first) and 2,326mm ±0,531 (second)(p=n/s). For the second angiographies, RA grafts exhibited larger diameters, related to pre-op obstructions between 90 and 100% (p=0,013). The grafted myocardial wall showed no interference with graft diameter. CONCLUSIONS: Pre-op coronary obstruction interferes in patency and diameters of RA grafts, more evidently for obstructions of 90% or greater. The grafted myocardial wall does not interfere with RA patency, although it does interfere with graft diameter. Remodeling was observed in RA grafts, correlating greater pre-op coronary obstructions and more evident increase in graft diameter similarly to the ITA grafts.
362

The value of noncoronary atherosclerosis for identifying coronary artery disease: Results of the Leipzig LIFE Heart Study

Weissgerber, Alexander 26 July 2018 (has links)
No description available.
363

The Effects of Coronary Artery Calcium Screening on Behavioral Modification, Risk Perception, and Medication Adherence Among Asymptomatic Adults: A Systematic Review

Mamudu, Hadii M., Paul, Timir K., Veeranki, Sreenivas P., Budoff, Matthew 01 October 2014 (has links)
Objective: To perform systematic review of the effects of screening for coronary artery calcium (CAC), a subclinical marker of coronary artery disease (CAD), on behavioral or lifestyle modification, risk perception, and medication adherence. Methods: We searched through CINAHL, PsychInfo, Web of Science, Cochrane Central Register of Control Trials, and PubMed (Medline) for studies on the effects of CAC screening in asymptomatic individuals across three major domains: behavioral modification, risk perception for CAD, and medication adherence. We extracted data from the retrieved studies, assessed and synthesized the information. Results: Of the 15 retrieved studies, three were randomized control trials and 12 were observational studies. CAC score was ascertained either as total score, quartiles, or standardized Agatston's ordinal scale. While all the 15 studies involved issues related to behavioral and medication adherence, four involved risk perception of CAD. Although no standardized approach was used in these studies, CAC screening enhanced medication adherence in 13 of the 15 studies, while the others were mixed. Conclusion: CAC screening improved medication adherence and could likely motivated individuals for beneficial behavioral or lifestyle changes to improve CAD. The mixed results suggest the need for further research because screening for subclinical atherosclerosis has significant implications for early detection and prevention of future cardiovascular events by aggressive risk factors modification.
364

Diagnosis and Treatment of Peripheral Arterial Disease Compared With Other Atherosclerotic Vascular Diseases in a University Primary Care Clinic

Ismail, Hassan, Jackson, Kyoo, Smith, Daniel 01 January 2006 (has links)
Background: Despite the fact that peripheral arterial disease (PAD) significantly increases the risk of cardiovascular mortality, it is significantly underdiagnosed and underrated. The purpose of this study was to evaluate the practice at a northeast Tennessee university primary care clinic regarding the diagnosis and treatment of PAD. Methods: A retrospective medical record survey was conducted to evaluate practice patterns in diagnosing and treating PAD in a university primary care clinic. A clinic population of 711 patients was selected using International Classification of Diseases-9 codes for coronary artery disease (CAD), cerebovascular disease (CVD), and/ or PAD. A sample of 180 patients (25.3%) was randomly selected using a systematic statistical method. Of these, 125 patients met the diagnostic criteria for CAD, CVD, and/or PAD. The study covered a 3-year period, from July 2001 until June 2004. Demographic and other data, including the use of antiplatelet therapy, were collected. Results: One hundred ten patients met all of the inclusion and exclusion criteria. Thirty-nine percent were males, and 61% were females. Overall, 79% had CAD, 53% had CVD, and 25% had PAD. Almost half of the patients had some combination of these. Only about 2% had PAD only compared with 36% with CAD only and 17% with CVD only. Although the prevalence of CAD and CVD (among other atherosclerotic vascular diseases) in our clinic was comparable to national figures, the prevalence of PAD was significantly lower (p = .004). The overall use of any antiplatelet agent was 84.2% for patients with only CAD and 80% for only CVD. There was not an adequate number of patients with only PAD to evaluate the use of antiplatelet therapy in this group. Conclusion: The low prevalence of PAD only (most PAD patients had coexisting CAD and CVD) indicates that PAD is underdiagnosed at our clinic. There was suboptimal use of aspirin and other antiplatelet drugs among patients with atherosclerotic vascular disease.
365

A Comparison of Patients Undergoing On- vs. Off-Pump Coronary Artery Bypass Surgery Managed with a Fast-Track Protocol

Grützner, Henrike, Forner, Anna Flo, Meineri, Massimiliano, Janai, Aniruddha, Ender, Jörg, Zakhary, Waseem Zakaria Aziz 04 May 2023 (has links)
The purpose of this study was to compare patients who underwent on- vs. off-pump coronary artery bypass surgery managed with a fast-track protocol. Between September 2012 and December 2018, n = 3505 coronary artery bypass surgeries were managed with a fast-track protocol in our specialized post-anesthesia care unit. Propensity score matching was applied and resulted in two equal groups of n = 926. There was no significant difference in ventilation time (on-pump 75 (55–120) min vs. off-pump 80 (55–120) min, p = 0.973). We found no statistically significant difference in primary fast-track failure in on-pump (8.2% (76)) vs. off-pump (6% (56)) groups (p = 0.702). The secondary fast-track failure rate was comparable (on-pump 12.9% (110) vs. off-pump 12.3% (107), p = 0.702). There were no significant differences between groups in regard to the post-anesthesia care unit, the intermediate care unit, and the hospital length of stay. Postoperative outcome and complications were also comparable, except for a statistically significant difference in PACU postoperative blood loss in on-pump (234 mL) vs. off-pump (323 mL, p < 0.0001) and red blood cell transfusion (11%) and (5%, p < 0.001), respectively. Our results suggest that on- and off-pump coronary artery bypass surgery in fast-track settings are comparable in terms of ventilation time, fast-track failure rate, and postoperative complications rate.
366

Infrared Thermographic Imaging of Chest Wall Perfusion in Patients Undergoing Coronary Artery Bypass Grafting

Rasche, Stefan, Kleiner, Christian, Müller, Jens, Rost, Antje, Ghazy, Tamer, Plötze, Katrin, Tetzlaff, Ronald, Matschke, Klaus, Bota, Olimpiu 04 June 2024 (has links)
Coronary artery disease represents a leading cause of death worldwide, to which the coronary artery bypass graft (CABG) is the main method of treatment in advanced multiple vessel disease. The use of the internal mammary artery (IMA) as a graft insures an improved long-term survival, but impairment of chest wall perfusion often leads to surgical site infection and increased morbidity and mortality. Infrared thermography (IRT) has established itself in the past decades as a non-invasive diagnostic technique. The applications vary from veterinary to human medicine and from head to toe. In this study we used IRT in 42 patients receiving CABG to determine the changes in skin surface temperature preoperatively, two hours, 24 h and 6 days after surgery. The results showed a significant and independent drop of surface temperature 2 h after surgery on the whole surface of the chest wall, as well as a further reduction on the left side after harvesting the IMA. The temperature returned to normal after 24 h and remained so after 6 days. The study has shown that IRT is sufficiently sensitive to demonstrate the known, subtle reduction in chest wall perfusion associated with IMA harvesting.
367

The study of in vitro superfused spiral modiolar artery bioassay on the endothelin-1 antagonistic activity of (+)-myriceric acid a and its novel synthetic tetracyclic terpenoids intermediates

Bao, Weier January 1900 (has links)
Master of Science / Department of Chemistry / Duy H. Hua / (+)-myriceric acid A is known as a non-peptide ETA receptor antagonist. It is isolated from the natural plant Myrica cerfera with 0.01% yield which is very low. The total synthesis of (+)-myriceric acid A is being pursued in Hua’s lab. (+)-myriceric acid A specifically blocks the vasoconstriction caused by endothelin-1 (ET-1). Because some derivatives of (+)-myriceric acid A were shown to have ET-1 receptor antagonistic effect, the tetracyclic terpenoid intermediates toward the total synthesis of (+)-myriceric acid A are postulated to have the similar antagonistic activities. The objective of this project is to study the release of vasoconstriction of these synthetic intermediates and compare their antagonistic potency. The ET-1 receptor antagonistic bioactivity of six (+)-myriceric acid A intermediates as well as (+)-myriceric acid A were evaluated by the in vitro spiral modiolar artery (SMA) bioassay. The synthetic intermediates which have not been reported in the literature were previously synthesized in Hua’s laboratory by Dr. Angelo Aguilar and Dr. Aibin Shi. Their synthesis was described in Dr. Aguilar’s PhD thesis. All the antagonistic effect evaluations were based on the SMA’s diameter changes. SMA’s diameter changes were induced by the superfusion of different extracellular solutions. The dose-response curves and straight lines were plotted to compare the antagonistic potency of these compounds. Based on the EC50 value of (+)-myriceric acid A intermediates (0.090 µM ~ 0.582 µM for the curves and 0.095 µM ~ 0.385 µM for the straight lines), all of the compounds have ET-1 receptor antagonistic activity, therefore the synthesis and screening of (+)-myriceric acid A intermediates is probably a promising route to develop new non-peptide ETA receptor antagonists.
368

The role of A3 adenosine receptors in protecting the myocardium from ischaemia/reperfusion injury

Hussain, A. January 2009 (has links)
Activation of A3 adenosine receptors has been shown to protect the myocardium from ischaemia reperfusion injury in a number of animal models. The PI3K - AKT and MEK1/2 - ERK1/2 cell survival pathways have been shown to play a critical role in regulating myocardial ischaemia reperfusion injury. In this study we investigated whether the A3 adenosine receptor agonist 2-CL-IB-MECA protects the myocardium from ischaemia reperfusion injury, when administered at reperfusion or post reperfusion and whether the protection involved the PI3K – AKT or MEK 1/2 – ERK1/2 cell survival pathways. In the Langendorff model of ischaemia reperfusion injury isolated perfused rat hearts underwent 35 minutes of ischaemia and 120 minutes of reperfusion. Administration of 2-CL-IB-MECA (1nM) at reperfusion significantly decreased infarct size to risk ratio compared to non-treated ischeamic reperfused control hearts. This protection was abolished in the presence of the PI3K inhibitor Wortmannin or MEK1/2 inhibitor UO126. Western blot analysis determined that administration of 2-CL-IB-MECA (1 nM) upregulated ERK1/2 phosphorylation. In the adult rat cardiac myocyte model of hypoxia/reoxygenation cells underwent 6 hours of hypoxia and 18 hours of reoxygenation. Administration of 2-CL-IB-MECA (1 nM) at the onset of reoxygenation significantly decreased cellular apoptosis and necrosis. Administration of 2-CL-IB-MECA (1nM) in the presence of the Wortmannin or UO126 significantly reversed this anti-apoptotic effect and anti-necrotic effect. Our data further showed that 2-CL-IB-MECA protects myocytes subjected to hypoxia/reoxygenation injury via decreasing cleaved-caspase 3 activity that was abolished in presence of the PI3K inhibitor but not in the presence of the MEK1/2 inhibitor UO126. Administration of 2-CL-IB-MECA (100nM) at the onset of reperfusion also significantly decreased infarct size to risk ratio in the ischaemic reperfused rat heart compared to controls that was reversed in the presence of Wortmannin or Rapamycin. This protection was associated with an increase in PI3K-AKT / p70S6K / BAD phosphorylation. 2-CL-IB-MECA (100nM) administered at reoxygenation also significantly protected adult rat cardiac myocytes from hypoxia/reoxygenation injury 28 in an anti-apoptotic and anti-necrotic manner. This anti-apoptotic/necrotic effect of 2-CL-IB-MECA was abolished in the presence Wortmannin. Furthermore, that this protection afforded by 2-CL-IB-MECA (100nM) when administered at reoxygenation was associated with a decrease in cleaved caspase 3 activity that was abolished in the presence of the Wortmannin Interestingly, postponing the administration of 2-CL-IB-MECA to 15 or 30 minutes after the onset of reperfusion significantly protected the isolated perfused rat heart from ischaemia reperfusion injury in a Wortmannin and UO126 sensitive manner. This protection was associated with an increase in AKT and ERK1/2 phosphorylation. Administration of the A3 agonist 2-CL-IB-MECA 15 or 30 minutes after the onset of reoxygenation significantly protected isolated adult rat cardiac myocytes subjected to 6 hours of hypoxia and 18 hours of reoxygenation from injury in an anti-apoptotic/necrotic manner. This anti-apoptotic was abolished upon PI3K inhibition with Wortmannin or MEK1/2 inhibition with UO126. The anti-necrotic effect of 2-CL-IB-MECA when administered 15 or 30 minutes post-reperfusion was not abolished in the presence of the inhibitors. Delaying the administration of 2-CL-IB-MECA to 15 or 30 minutes after reoxygenation was associated with a decrease in cleaved-caspase 3 activity that was abolished in the presence of Wortmannin but not in the presence of the MEK 1/2inhibitor UO126. Collectively, we have demonstrated for the first time that administration of 2-CL-IB-MECA at the onset of reperfusion protects the ischaemic reperfused rat myocardium from lethal ischaemia reperfusion injury in a PI3K and MEK1/2 sensitive manner. Delaying the administration of 2-CL-IB-MECA to 15 or 30 minutes after the onset of reperfusion of reoxygenation also significantly protects the isolated perfused rat heart from ischaemia reperfusion injury and the adult rat cardiac myocyte from hypoxia/reoxygenation injury in an anti apoptotic / necrotic manner. Furthermore, that this protection is associated with recruitment of the PI3K-AKT and MEK1/2 – ERK1/2 cell survival pathways.
369

3-Nitrotyrosine as an indicator of the disease state claudication

Dean, Sadie January 2009 (has links)
3-nitrotyrosine (3NT), a stable end product arising from the interaction of proteins and reactive nitrogen species such as peroxynitrite, is produced during periods of oxidative stress. 3NT is, therefore, of interest as a potential biomarker in a variety of disease states where oxidative stress is known to be involved in the pathology, for example intermittent claudication. The aim of this thesis was to develop sensitive and specific immunoassays to assess the levels of 3NT in plasma samples from claudicants and to investigate the protein nitration profile. Clinical data and plasma samples were collected from claudicant (n=33) and control (n=6) subjects. Analysis of data confirmed the difficulty of using parameters such as ankle brachial index (ABI) in diagnosis, supporting the need for investigations into potential biomarkers. Development of indirect and competitive ELISAs using electrochemically nitrated bovine serum albumin as the standard revealed that the detection of 3NT was dependent on the antibody being able to access the 3NT-residues within the protein. Various denaturing conditions and different types of microtitre plate were utilised during development. Initially the presence of 3NT in claudicant or control whole plasma samples could only be detected using dot blot immunodetection. Affinity purification techniques for the fractionation of the plasma proteins were therefore applied. Subsequently, 3NT-containing plasma proteins were found to be present in all of the claudicant and control samples using the developed competitive ELISA. Proteomic analysis of the 3NT-affinity purified samples, using MALDI-MS and LC-ESI-MS/MS, confirmed the presence of human serum albumin, serotransferrin and apolipoprotein A1 and A2 precursors within those protein bands staining immunopositive for 3NT on SDS-PAGE gels. The identification of apolipoprotein A1 within 3NT-immunopositive bands confirms previous reports suggesting the oxidative modification of HDL may contribute to the link between inflammation and the pathology of atherosclerosis.
370

Evaluation of a Laser Doppler System for Myocardial Perfusion Monitoring

Fors, Carina January 2007 (has links)
Coronary artery bypass graft (CABG) surgery is a common treatment for patients with coronary artery disease. A potential complication of CABG is myocardial ischemia or infarction. In this thesis, a method - based on laser Doppler flowmetry (LDF) - for detection of intra- and postoperative ischemia by myocardial perfusion monitoring is evaluated. LDF is sensitive to motion artifacts. In previous studies, a method for reduction of motion artifacts when measuring on the beating heart has been developed. By using the ECG as a reference, the perfusion signal is measured in intervals during the cardiac cycle where the cardiac motion is at a minimum, thus minimizing the artifacts in the perfusion signal. The aim of this thesis was to investigate the possibilities to use the ECG-triggered laser Doppler system for continuous monitoring of myocardial perfusion in humans during and after CABG surgery. Two studies were performed. In the first study, changes in myocardial perfusion during CABG surgery were investigated (n = 13), while the second study focused on postoperative measurements (n = 13). In addition, an ECG-triggering method was implemented and evaluated. It was found that the large variations in myocardial perfusion during CABG surgery could be monitored with the ECG-triggered laser Doppler system. Furthermore, a perfusion signal of good quality could be registered postoperatively from the closed chest in ten out of thirteen patients. In eight out of ten patients, a proper signal was obtained also the following morning, i.e., about 20 hours after probe insertion. The results show that respiration and blood pressure can have an influence on the perfusion signal. In conclusion, the results indicate that the method is able to detect fluctuations in myocardial perfusion under favourable circumstances. However, high heart rate, abnormal cardiac motion, improper probe attachment and limitations in the ECG-triggering method may result in variations in the perfusion signal that are not related to tissue perfusion. / Varje år utförs omkring 4500 kranskärlsoperationer i Sverige. En allvarlig komplikation som kan uppstå efter operationen är otillräcklig blodförsörjning till hjärtmuskeln. Den här licentiatavhandlingen handlar om utveckling och utvärdering av en metod, baserad på laserdopplerteknik, för att kunna upptäcka nedsatt blodperfusion i hjärtmuskeln på ett tidigt stadium. Laserdopplertekniken är känslig för rörelsestörningar. I tidigare studier har en metod för reducering av rörelsestörningar vid mätning på slående hjärta tagits fram. Med EKG:t som referens mäts blodperfusionen i de faser under hjärtcykeln då hjärtats rörelse är som minst, vilket minskar bidraget av rörelsestörningar i blodperfusionssignalen. I den här avhandlingen undersöks om metoden kan användas för kontinuerlig övervakning av hjärtmuskelns blodperfusion på patienter under och efter hjärtoperationer. Två studier har genomförts: en där hjärtmuskelns perfusion mättes i olika faser under kranskärlsoperationer och en där mätproben lades in i hjärtmuskeln under operationen och mätningar gjordes under det första dygnet efter operationen. Det visade sig vara möjligt att följa förändringar i hjärtmuskelns blodperfusion under operation. Det var även möjligt att registrera en perfusionssignal av god kvalitet efter operationen då bröstkorgen var stängd. Hos åtta av tio patienter erhölls en bra signal även morgonen efter operationen, dvs. ca 20 timmar efter att proben lades in. Resultaten visar också att andning och blodtryck kan ha en påverkan på blodperfusionssignalen. Slutsatsen av arbetet är att det går att se variationer i hjärtmuskelns blodperfusion med EKG-triggad laserdoppler under vissa förutsättningar. Signalen är dock i många fall svårtolkad på grund av att t ex hög hjärtfrekvens, onormal hjärtväggsrörelse eller ändrad probposition sannolikt kan ge variationer i perfusionssignalen som inte är relaterade till blodflödesförändringar. / Report code: LIU-TEK-LIC-2007:35.

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