938 resultados para gradient descent
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Dissertação de mestrado em Técnicas de Caraterização e Análise Química
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OBJECTIVE: To analyze late clinical evolution after surgical treatment of children, with reparative and reconstructive techniques without annular support. METHODS: We evaluated 21 patients operated upon between 1975 and 1998. Age 4.67±3.44 years; 47.6% girls; mitral insufficiency 57.1% (12 cases), stenosis 28.6% (6 cases), and double lesion 14.3% (3 cases). The perfusion 43.10±9.50min, and ischemia time were 29.40±10.50min. The average clinical follow-up in mitral insufficiency was 41.52±53.61 months. In the stenosis group (4 patients) was 46.39±32.02 months, and in the double lesion group (3 patients), 39.41±37.5 months. The echocardiographic follow-up was in mitral insufficiency 37.17±39.51 months, stenosis 42.61±30.59 months, and in the double lesion 39.41±37.51 months. RESULTS: Operative mortality was 9.5% (2 cases). No late deaths occurred. In the group with mitral insufficiency, 10 (83.3%) patients were asymptomatic (p=0.04). The majorit y with mild reflux (p=0.002). In the follow-up of the stenosis group, all were in functional class I (NYHA); and the mean transvalve gradient varied between 8 and 12mmHg, average of 10.7mmHg. In the double lesion group, 1 patient was reoperated at 43 months. No endocarditis or thromboembolism were reported. CONCLUSION: Mitral stenosis repair has worse late results, related to the valve abnormalities and associated lesions. The correction of mitral insufficiency without annular support showed good long-term results.
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OBJECTIVE: To evaluate prior mitral surgical commissurotomy and echocardiographic score influence on the outcomes and complications of percutaneous mitral balloon valvuloplasty. METHODS: We performed 459 complete mitral valvuloplasty procedures. Four hundred thirteen were primary valvuloplasty and 46 were in patients who had undergone prior surgical commissurotomy. The prior commissurotomy group was older, had higher echo scores, and a tendency toward a higher percentage of atrial fibrillation. RESULTS: When the groups were compared with each other, no differences were found in pre- and postprocedure mean pulmonary artery pressure, mean mitral gradient, mitral valve area, and mitral regurgitation . Because we found no significant differences, we subdivided the entire group based on echo scores, those with echo scores <=8 and those with echo scores >8 the mitral valve area being higher in the <=8 echo score group 2.06±0.42 versus 1.90±0.40cm² (p=0.0090) in the >8 echo score group. CONCLUSION: Dividing the groups based on echo score revealed that the higher echo score group had smaller mitral valve areas postvalvuloplasty.
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Dissertação de mestrado em Técnicas de Caracterização e Análise Química
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OBJECTIVE: To evaluate the immediate results of percutaneous mechanical mitral commissurotomy. METHODS: Thirty patients underwent percutaneous mechanical mitral commissurotomy performed with a Cribier's metallic valvulotome from 8/11/99 to 2/4/00. Mean age was 30.7 years, and 73.3% were women. With regards to functional class, 63.3% were class III, and 36.7% were class IV. The echocardiographic score had a mean value of 7.5± 1.8. RESULTS: The mitral valve area increased from 0.97±0.15cm² to 2.16±0.50cm² (p>0.0001). The mean diastolic gradient decreased from 17.9±5.0mmHg to 3.2±1.4mmHg. The mean left atrial pressure decreased from 23.6±5.4mmHg to 8.6±3.1mmHg, (p>0.0001). Systolic pressure in the pulmonary artery decreased from 52.7±18.3mmHg to 32.2±7.4mmHg. Twenty-nine cases were successful. One patient developed severe mitral regurgitation. Interatrial septal defect was observed and one patient. One patient had cardiac tamponade due to left ventricular perforation. No deaths occurred. CONCLUSION: This method has proven to be safe and efficient in the treatment of rheumatic mitral stenosis. The potential advantage is that it can be used multiple times after sterilization, which decreases procedural costs significantly.
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Mitral valvuloplasty is efficient for repairing mitral valve disease with few complications. In some cases, obstruction of the left ventricular outflow tract may occur due to systolic anterior motion of the mitral valve. We report the case of a patient with this complication and a pressure gradient between the left ventricle and the aorta of 130 mm Hg after mitral valvuloplasty with implantation of a Gregori's ring. The management was clinical with suspension of the vasoactive drugs and introduction of a beta-blocker. Two years after the surgery, the patient is asymptomatic and has a normal life.
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OBJECTIVE: To analyze the efficacy of percutaneous transluminal septal alcoholization in the treatment of refractory obstructive hypertrophic cardiomyopathy (HOC). METHODS: The patients were referred for alcoholization after Doppler echocardiography. Before and after alcoholization, the intraventricular pressure gradient was recorded. Alcoholization was performed with a 3mL injection of absolute alcohol through a coronary angioplasty balloon catheter. The procedure was concluded after a significant reduction or abolition of the pressure gradient. RESULTS: Of 22 patients, 18 (81.8%) successfully concluded the procedure with a reduction in intraventricular pressure gradient at baseline (from 67.6±24.2 mmHg to 3.8± 1.9 mmHg, p<0.005) and after extrasystole (from 110.4± 24.2 mmHg to 9.6±2.6 mm Hg, p<0.005). A significant reduction in mean interventricular septal thickness (from 2± 0.3 mm to 1.7±0.2 mm, p<0.005) and in peak pressure gradient (from 90.7±23.5 mmHg to 6.1±1.4 mmHg, p<0.005) was observed on Doppler echocardiography after 6 months, when all patients were in functional class I. The most frequent acute complication, present in 11% of the patients, was the need for definitive pacing implantation. Relapse of the symptoms and reappearance of the pressure gradient occurred in 16.6% of the patients. One patient (5.5%) died probably due to a diffuse coronary spasm prior to the procedure, and another died suddenly on late follow-up. CONCLUSION: Percutaneous transluminal septal alcoholization is effective and safe in the treatment of HOC.
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OBJECTIVE: To report short and midtem follow-up results of balloon aortic valvuloplasty to treat congenital aortic stenosis. METHODS: Seventy-five patients (median age: 8 years) underwent the procedure through the retrograde femoral or carotid route. RESULTS: The procedure was completed in 74 patients (98.6%). The peak-to-peak systolic gradient dropped from 79.6±27.7 to 22.3±17.8 mmHg (P<0.001), the left ventricular systolic pressure dropped from 164±39.1 to 110±24.8 mmHg (P<0.001), and the left ventricular end diastolic pressure dropped from 13.3±5.5 to 8.5±8.3 mmHg (P< 0.01). Four patients (5.3%) died due to the procedure. Aortic regurgitation (AoR) appeared or worsened in 27/71 (38%) patients, and no immediate surgical intervention was required. A mean follow-up of 50±38 months was obtained in 37 patients. Restenosis and significant AoR were observed in 16.6% of the patients. The estimates for being restenosis-free and for having significant AoR in 90 months were 60% and 50%, respectively. CONCLUSION: Aortic valvuloplasty was considered the initial palliative method of choice in managing congenital aortic stenosis, with satisfactory short- and midterm results.
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OBJECTIVE: To identify the variables that may be involved in the persistence of symptoms (functional class II, III, or IV vs. I) in patients being followed up for 30 years after surgical repair of tetralogy of Fallot. METHODS: Fifty-three patients (27 women), who underwent corrective surgery for tetralogy of Fallot between 1960 and 1970, were studied. Their ages ranged from 7 months to 26 years. At the end of follow-up, 13 patients were asymptomatic and the remaining were in functional class II (N=24), III (N=15), and IV (N=1). To differentiate asymptomatic from symptomatic patients, the following variables were analyzed: age at surgery, need for widening the pulmonary ring and trunk, need for a second (2nd OP) or 3rd operation, residual defect of the interventricular septum, residual regurgitation of the pulmonary valve, systolic gradient through the right ventricular outflow tract, right ventricular dilation or hypertrophy (RVH), cardiothoracic index (CTI), right and left ventricular ejection fraction (RVEF/LVEF), and arrhythmias. RESULTS: The univariate analysis showed an association between the presence of symptoms and the 2nd OP (P=0.03), an increase in the CTI (P=0.0001), moderate to severe RVH (P=0.002), and dilation (P=0.0003). In the logistic regression model, the combination of the 2nd OP (P=0.008), the RVH (P=0.002), and the reduction in RVEF (P=0.01) determined the presence of symptoms. CONCLUSION: Despite the surgical treatment, right ventricular remodeling and performance were the major determinants in the late follow-up of tetralogy of Fallot.
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Surgical procedures such as osteotomy and hip replacement involve the cutting of bone with the aid of various manual and powered cutting instruments including manual and powered bone saws. The basic mechanics of bone sawing processes are consistent with most other material sawing processes such as for wood or metal. Frictional rubbing between the blade of the saw and the bone results in the generation of localised heating of the cut bone. Research studies have been carried out which consider the design of the bone saw which deals with specifics of the saw teeth geometry and research which examines the effect of drilling operations on heating of the bone has shown that elevated temperatures will occur from frictional overheating. This overheating in localised areas is known to have an impact on the rate of healing of the bone post operation and the sharpness life of the blade. The purpose of this study was to measure the temperature at three zones at fixed intervals of 3mm, 6mm, and 9mm away from the cutting zone. It should be noted that it was the first time that this measurement technique was used to measure the temperature gradient through the bone specimen thereby establishing the extent to which clinicians are experiencing thermal injury during sawing of bone while using a reciprocating saw. The effect of various cutting feed rate on temperature elevation was also investigated in this research. The results showed that there will be a region of bone at least 9mm either side of the cutting blade experiencing thermal injury as temperatures in this region exceeded the threshold temperature of 44°C for necrosis (cell death).
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ბაგინეთში, ქართლის მთის ჩრდილო-აღმოსავლეთ კალთაზე, მდინარე მტკვრის მარჯვენა სანაპიროზე, გამოიყოფა რამდენიმე საკმაოდ ფართო და გრძელი ტერასა, რომლებიც დაახლოებით 30 ჰექტარზე ვრცელდება. პირველ ტერასაზე, სადაც უკვე გამოვლენილი არქეოლოგიური ნაგებობები და შესაბამისი ელექტრული ანომალია დაახლოებით 750 კვ.მ-ია ჩატარდა დეტალური გეოფიზიკური კვლევა ძიების ელექტრული მეთოდით. კვლევის შედეგად გამოვლენილი ანომალური უბანი სხვა ანომალური უბნებისაგან განსხვავდება სიღრმეში განაწილების თავისებურებით, რაც მიწის ქვეშ დიდი არქეოლოგიური ნაგებობის არსებობაზე უნდა მიუთითებდეს.
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Abstract Background: Transcatheter aortic valve implantation has become an option for high-surgical-risk patients with aortic valve disease. Objective: To evaluate the in-hospital and one-year follow-up outcomes of transcatheter aortic valve implantation. Methods: Prospective cohort study of transcatheter aortic valve implantation cases from July 2009 to February 2015. Analysis of clinical and procedural variables, correlating them with in-hospital and one-year mortality. Results: A total of 136 patients with a mean age of 83 years (80-87) underwent heart valve implantation; of these, 49% were women, 131 (96.3%) had aortic stenosis, one (0.7%) had aortic regurgitation and four (2.9%) had prosthetic valve dysfunction. NYHA functional class was III or IV in 129 cases (94.8%). The baseline orifice area was 0.67 ± 0.17 cm2 and the mean left ventricular-aortic pressure gradient was 47.3±18.2 mmHg, with an STS score of 9.3% (4.8%-22.3%). The prostheses implanted were self-expanding in 97% of cases. Perioperative mortality was 1.5%; 30-day mortality, 5.9%; in-hospital mortality, 8.1%; and one-year mortality, 15.5%. Blood transfusion (relative risk of 54; p = 0.0003) and pulmonary arterial hypertension (relative risk of 5.3; p = 0.036) were predictive of in-hospital mortality. Peak C-reactive protein (relative risk of 1.8; p = 0.013) and blood transfusion (relative risk of 8.3; p = 0.0009) were predictive of 1-year mortality. At 30 days, 97% of patients were in NYHA functional class I/II; at one year, this figure reached 96%. Conclusion: Transcatheter aortic valve implantation was performed with a high success rate and low mortality. Blood transfusion was associated with higher in-hospital and one-year mortality. Peak C-reactive protein was associated with one-year mortality.
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The present diploma thesis analyses the German political understanding of social inequalities in health (SIH) among children and adolescents, and explores the political strategies that are perceived as most effective to tackle SIH. The study is based on the qualitative content analysis of official political documents developed at different political levels, which were the national level as well as two purposefully selected counties, Mecklenburg-Vorpommern and Niedersachsen. The study's findings indicate a beginning awareness of the existence of SIH in Germany. Nevertheless, this judgement refers to few publishing ministries only, both at national and county levels. The suggested approaches to tackle SIH vary significantly among the analysed documents, and no consensus can be identified with regard to the preference of upstream or downstream policies. The existence of the social gradient is not criticised in any of the analysed data. However, there seems to be a common agreement on the importance of setting related interventions and the contribution of both the national, regional, and local politic levels. As the absence of a central coordinator can explain these highly heterogeneous findings, key recommendations concern the establishment of a nation-wide coordinator and a nation-wide collection of best practice examples. Here, the Federal Centre for Health Education has an adequate position and the required competences to act as a coordinator and facilitator. Further requirements for a successful reduction of SIH in Germany are the extension of a continuous communication between all actors, the adoption of the planned German Prevention Law, and the nation-wide and early promotion of children as part of education policies in the federal states.
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The polychaete composition and distribution within mussel beds were studied in order to assess organic pollution due to domestic sewage in a rocky shore of Mar del Plata (Argentina) during 1997. Four stations and a control site were randomly sampled around the local effluent. Quantitative data on polychaetes, as well as sediment accumulated among mussels and its organic carbon content were measured. Polychaete distribution patterns are related to the organic matter gradient, being Capitella cf. capitata, Neanthes succinea (Frey & Leuckart, 1847) and Boccardia polybranchia (Haswell, 1885) the dominant indicator species close to the effluent. At medial distances, the cirratulids Caulleriella alata (Southern, 1914) and Cirratulus cirratus (Müller, 1776) are very important in abundance. The syllids Syllis prolixa Ehlers, 1901 and S. gracilis Grube, 1840 are distributed along the study area, but dominate at the medial stations and at the control site. The orbiniid Protoariciella uncinata Hartmann-Schröder, 1962 is subdominant at the control station.
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In the estuary of the Mamanguape River (Paraíba, Brazil), a new collection technique was developed and applied with virgin poles of mangrove trees Avicennia schaueriana (Verbenaceae), Rhizophora mangle (Rhizophoraceae), and Laguncularia racemosa (Combretaceae), taking into account wood preference, water salinity and depth influence during teredinid larval settlement. Sets of poles were vertically fixed in the riverbed at three sites along a decreasing salinity gradient, where they stayed for four months. The poles were collected and divided into upper, median, and lower segments, in agreement with different immersion regimes. An increase of 239% was obtained in the number of individuals when compared to a previous study in the same area using a different methodology. The species Teredo bartschi (Clapp, 1923), Nausitora fusticula (Jeffreys, 1860) and Bankia fimbriatula Moll & Roch, 1931 were registered in both studies, and the species Psiloteredo healdi (Bartsch, 1931) is here registered for the first time as occurring in that estuary. The species Neoteredo reynei (Bartsch, 1920), previously registered on tree branches of the mangrove habitat, was not found in the present work. Bankia fimbriatula, the most abundant species, did not show preference for any substratum but occurred significantly on the lower segment of the poles. N. fusticula, second in abundance, preferred to settle on poles of A. schaueriana and on any of the three segments. Aiming to assess the habitat variations, a more accurate study on teredinids diversity in mangrove ecosystems should be performed through a concomitant analysis from tree branches of the mangrove habitat, as well as from poles of mangrove trees or panels made of pine wood or mangrove trees wood. These collection devices should be maintained along a decreasing salinity gradient exposed to different tide levels.