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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.
11

Risk Factors and Predictive Modeling for Aortic Aneurysm

Vanichbuncha, Tita January 2012 (has links)
In 1963 – 1965, a large-scale health screening survey was undertaken in Sweden and this data set was linked to data from the national cause of death register. The data set involved more than 60,000 participants whose age at death less than 80 years. During the follow-up period until 2007, a total of 437 (338 males and 99 females) participants died from aortic aneurysm. The survival analysis, continuation ratio model, and logistic regression were applied in order to identify significant risk factors. The Cox regression after stratification for AGE revealed that SEX, Blood Diastolic Pressure (BDP), and Beta-lipoprotein (BLP) were the most significant risk factors, followed by Cholesterol (KOL), Sialic Acid (SIA), height, Glutamic Oxalactic Transaminase, Urinary glucose (URIN_SOC), and Blood Systolic Pressure (BSP). Moreover, SEX and BDP were found as risk factors in almost every age group. Furthermore, BDP was strongly significant in both male and female subgroup.   The data set was divided into two sets: 70 percent for the training set and 30 percent for the test set in order to find the best technique for predicting aortic aneurysm. Five techniques were implemented: the Cox regression, the continuation ratio model, the logistic regression, the back-propagated artificial neural network, and the decision tree. The performance of each technique was evaluated by using area under the receiver operating characteristic curve. In our study, the continuation ratio and the logistic regression outperformed among the other techniques.
12

Des Anévrysmes de l'aorte thoracique descendante ....

Vallois, Felix. January 1884 (has links)
Thèse--Faculté de médecine de Paris.
13

Bacterial intracranial aneurysms

Aspoas, A R 06 April 2017 (has links)
No description available.
14

Polymeric Endo-Aortic Paving (PEAP): Initial Development of a Novel Treatment for Abdominal Aortic Aneurysms

Ashton, John Hardy January 2010 (has links)
Abdominal aortic aneurysm (AAA) is a prevalent disease in developed countries. While endovascular aneurysm repair is fairly successful, it has shortcomings. Polymeric endoluminal paving and sealing is a method that has previously been developed to treat a range of diseases. Our goal is to further develop this technique to treat AAA, a process we have named polymeric endo-aortic paving (PEAP). We hypothesize that PEAP will overcome many of the limitations associated with EVAR by providing a minimally invasive treatment which can be used on patients with complicated AAA geometries and reducing incidence of migration and endoleak. Additionally, we plan to incorporate drug delivery into PEAP to improve efficacy. The purpose of this work was to evaluate a potential graft material for PEAP and to develop a thrombus mimic which will aid in further PEAP development. Blends of polycaprolactone/polyurethane (PCL/PU) were assessed by characterizing their mechanical, thermoforming, and degradation properties. PCL/PU grafts have a similar stiffness to aortic tissue and can be thermoformed at temperatures approaching 37 degrees C. Blending PCL with PU significantly reduces PCL's degradation. An anisotropic hyperelastic strain energy function was developed for the PCL/PU blends and finite element modeling (FEM) was used to show that stress reduction on the AAA wall that can be achieved by PEAP is similar to current EVAR. Stiffness varies throughout the AAA thrombus, and thrombus mimics were developed that have similar stiffness, components, and structure to native AAA thrombus.
15

Anatomy determines etiology in thoracic aortic aneurysm

Vapnik, Joshua 08 April 2016 (has links)
BACKGROUND: It is well established that thoracic aortic aneurysms (TAA) and abdominal aortic aneurysms (AAA) have different risk factors, clinical features, and genetic influences. Differences between and amongst subtypes of TAAs have received less attention. Despite observations of divergent clinical outcomes between ascending thoracic aortic aneurysms (ATAAs) and descending thoracic aortic aneurysms (DTAAs), etiologic factors determining the anatomic distribution of these aneurysms are not well understood. METHODS: From 3,247 patients registered in an institutional Thoracic Aortic Center Database from July 1992 through August 2013, we identified 921 patients with full aortic dimensional imaging by CT or MRI scan with TAA > 3.5 cm and without evidence of aortic dissection (AoD). Patients were analyzed in three groups: isolated ATAA (n=677), isolated DTAA (n=97), and combined ATAA and DTAA (n=146). RESULTS: Patients with a DTAA, alone or with coexistent ATAA, had significantly more hypertension (80.6% vs. 61.8%, p<.001) and a higher burden of atherosclerotic disease ( 86.7% vs. 7.5%, p<.001) ) and were more likely to be female (59.3% vs. 29.5%, P<.001). Conversely, patients with isolated ATAA were significantly younger (average age 59.5 vs. 71, p<.001), and contained almost every case of overt genetically-triggered TAA. Patients with isolated DTAA were demographically indistinguishable from patients with combined ATAA and DTAA. In follow up, patients with isolated DTAA, or with ATAA and DTAA, experienced significantly more aortic events (aortic dissection/rupture) and had higher mortality than patients with isolated ATAA. CONCLUSIONS: Based on patient characteristics and outcomes, subtypes of TAA emerge. DTAA with or without associated ATAA or AAA appears to be a disease more highly associated with atherosclerosis, hypertension, and advanced age. In contrast, isolated ATAA appears to be a clinically distinct entity with a higher burden of genetically triggered disease. These data have important implications for familial screening recommendations for TAA.
16

Computed tomography in subarachnoid haemorrhage:studies on aneurysm localization, hydrocephalus and early rebleeding

Jartti, P. (Pekka) 05 October 2010 (has links)
Abstract Subarachnoid haemorrhage (SAH) is a life-threatened disease with poor outcome. It is usually caused by an intracranial aneurysm (IA) rupture and rapid diagnosis and treatment are of great importance. Computed tomography (CT) is a reliable method to detect the blood in the subarachnoid (SA) spaces. Digital subtraction angiography (DSA) offers dynamic and morphological information of a ruptured IA. The treatment options for excluding an aneurysm from the main circulation are neurosurgical clipping and endovascular procedures. The purpose of the present study was to evaluate the risk factors of acute hydrocephalus (HC) and the reliability to localize the ruptured aneurysm based on non-contrast CT. The aim was also to compare the effect of neurosurgical and endovascular treatment on the development of chronic HC, and evaluate the incidence and the risk factors of early rebleeding (&lt;  30 days) after coiling. The data of 180 operated patients with a ruptured IA were checked. Two neuroradiologists separately located the IAs based on non-contrast CT. The analyses of blood amount and distribution was a reliable method for estimating the location of ruptured middle cerebral artery (MCA) aneurysms and anterior communicate artery (ACoA) aneurysms. Intracerebral haemorrhage (ICH) was a predictor for detecting the precise site. The results confirmed that intraventricular haemorrhage (IVH) was the most consistent single risk factor for the development of acute HC. Haemorrhage in the basal region and the large total blood amount in the SA spaces were strong predictors. The effect of early treatment modality for ruptured IAs on the development of chronic HC with 102 clipped and 107 coiled patients was compared. The treatment method used was not significantly associated with the occurrence of chronic HC or the need for shunt operation. The incidence and risk factors of early rebleeding after coiling were investigated in 194 consecutive acutely (within 3 days) coiled patients with ruptured IAs. The incidence of early rehaemorrhage was 3.6%. The presence of ICH at admission and poor clinical condition were significant predictors for rebleeding. An early rehaemorrhage appeared as an enlargement of the ICH in all of these patients. In conclusion, the non-contrast CT is a reliable method to detect the location of ruptured IA in patients with MCA and ACoA aneurysms. The risk factor for the development of acute HC is IVH. Other predictors are the total SA blood amount and blood in the basal regions. The treatment method used for acutely ruptured IA has no significant effect on the occurrence of chronic HC. The incidence of early rebleeding after coiling is low. The risk factors of rebleeding are the presence of ICH and poor clinical condition. Rehaemorrhage appears often as an enlargement of the ICH.
17

Endovascular treatment of 467 consecutive intracranial aneurysms in Oulu University Hospital:angiographic and clinical results

Isokangas, J.-M. (Juha-Matti) 22 December 2006 (has links)
Abstract The purpose of the study was to analyze the angiographic and clinical results of endovascularly treated intracranial aneurysms in Oulu University Hospital, Finland. The study population consisted of 416 consecutive patients (467 aneurysms, 332 ruptured), who were referred for endovascular treatment of intracranial aneurysm(s) between December 1993 and July 2004. Technical failures were analyzed for an assesment of technical feasibility. Angiographic results were assessed using modified Raymond Classification. Clinical results were analyzed from patient files using the Glasgow Outcome Scale (GOS). Patient, aneurysm, and procedure related variables were tested with an intention to find the predictors of the angiographic and clinical outcome. The clinical effects on presenting symptoms were analyzed for a subgroup of patients with a symptomatic unruptured aneurysm (n = 30). The mean results on technical feasibility, complications, and angiographic results were separately assessed for three time periods (1993–1997, 1998–2000 and 2001–2004) to demonstrate potential significant changes in outcome. Endovascular treatment of saccular aneurysms was technically feasible in 91.4% of the treatments. Initially, 25.7% of the aneurysms were completely occluded, 57.9% had a neck remnant, and 16.3% remained incompletely occluded. In follow-up, the rates for complete occlusions, neck remnants and incomplete occlusions were 37.6%, 49.7% and 12.7%, respectively. Small aneurysm size predicted complete aneurysm occlusion, while a wide aneurysm neck and location in the posterior circulation predicted incomplete occlusion. In follow-up (mean 38.2 months), 78.1% of the patients with a ruptured aneurysm and 92.3% of the patients with an unruptured aneurysm had resumed independent life (GOS 4-5). The predictors of good outcome were young age, good preprocedural clinical condition, small amount of blood in CT scan, and uncomplicated procedure. Ten of the treated aneurysms involved intracranial bleeding in follow-up, and the annual risk for bleeding after endovascular treatment was 0.95% among the patients with ruptured aneurysms and 0.33% among those with unruptured aneurysms. The risk of bleeding was associated with larger aneurysm size and lower occlusion grade. In the subgroup of symptomatic unruptured aneurysms, 53.4% of the patients showed either resolution or improvement of the symptoms after treatment. The rates of procedural complications, morbidity, and mortality were 16.5%, 6.7%, and 1.7%, respectively. The risk for procedural complications was higher when the balloon remodeling technique was used and lower in retreatments. Technical feasibility (85.6%, 90.6%, and 95.7%, respectively) and the percentage of complete occlusions (initially 16.5%, 23.0%, and 32.9%, respectively) were significantly improved by increased experience, while no statistical difference was detected in the total procedural complication rates (15.4%, 15.7%, and 18.3%, respectively) or the combined procedural morbidity and mortality rates (8.0%, 8.3%, and 9.1%, respectively). All six dissecting aneurysms treated with parent artery occlusion or the stent remodeling technique resulted in complete occlusions. The present results confirmed endovascular treatment of intracranial aneurysms as a feasible, safe, and effective method in preventing further bleeding of aneurysms. Increased experience in a single center improved the feasibility of the treatment as well as the angiographic results.
18

SURGICAL MANAGEMENT OF INFECTED THORACIC ANEURYSMS

Usui, Akihiko 08 1900 (has links)
No description available.
19

Postoperativ livskvalitet hos patienter med abdominellt aortaaneurysm

Haglund, Helena, Bernhardsson, Jenny January 2016 (has links)
Bakgrund: Idag finns det begränsad kunskap och forskning kring hur patienter som genomgått behandling för abdominellt aortaaneurysm (AAA) upplever sin postoperativa livskvalitet och hälsa. Detta kan medföra svårigheter att tillmötesgå patienternas postoperativa omvårdnadsbehov. Syfte: Undersöka hur patienter som diagnostiserats med AAA upplever sin livskvalitet efter operation och vilket omvårdnadsbehov som finns, samt belysa vilka omvårdnadsåtgärder som kan främja livskvaliteten hos dessa patienter. Metodbeskrivning: Arbetet inkluderar kvantitativ och kvalitativ forskning kring ämnet som sökts fram med hjälp av relevanta sökord via databaserna PubMed och CINAHL. Vid bearbetning av studierna togs hänsyn till etiska överväganden samt kvaliteten på studierna. Huvudresultat: Under den tidiga postoperativa perioden upplever patienterna en försämrad livskvalitet jämfört med preoperativt, där patienter som genomgått endovaskulär behandling upplever en bättre livskvalitet än de som genomgått öppen operation. Senare i den postoperativa perioden är båda patientgrupperna tillbaka på samma eller bättre livskvalitetsnivå än preoperativt och skillnaderna mellan grupperna har jämnats ut. Det främsta omvårdnadsbehovet som kan finnas är behovet av kunskap. Patienterna saknar information om postoperativa symtom, potentiella komplikationer och rehabiliteringsperioden överlag. Genom information kan de flesta patienterna ges bättre förutsättningar att hantera den postoperativa livssituationen och därmed uppnå en högre livskvalitet och hälsa. Slutsats: Samtliga patienter upplevde en försämrad postoperativ livskvalitet, med en fördel till den endovaskulära behandlingen kort tid efter operation. Med tiden återgår eller förbättras livskvaliteten för båda grupper, med en fördel till öppen kirurgi. Mer information kring diagnos och behandling önskas av patienterna, då det tros kunna främja den postoperativa livskvaliteten och därmed hälsan.
20

Modeling of Flow in an In Vitro Aneurysm Model: A Fluid-Structure Interaction Approach

Hao, Qing 16 December 2010 (has links)
Flow velocity field, vorticity and circulation and wall shear stresses were simulated by FSI approach under conditions of pulsatile flow in a scale model of the rabbit elastin-induced aneurysm. The flow pattern inside the aneurysm sac confirmed the in vitro experimental findings that in diastole time period the flow inside the aneurysm sac is a stable circular clock-wise flow, while in systole time period higher velocity enters into the aneurysm sac and during systole and diastole time period an anti-clock circular flow pattern emerged near the distal neck; in the 3-D aneurysm sac, the kinetic energy per point is about 0.0002 (m2/s2); while in the symmetrical plane of the aneurysm sac, the kinetic energy per point is about 0.00024 (m2/s2). In one cycle, the shape of the intraaneurysmal energy profile is in agreement with the experimental data; The shear stress near the proximal neck experienced higher shear stress (peak value 0.35 Pa) than the distal neck (peak value 0.2 Pa), while in the aneurysm dome, the shear stress is always the lowest (0.0065 Pa). The ratio of shear stresses in the proximal neck vs. distal neck is around 1.75, similar to the experimental findings that the wall shear rate ratio of proximal neck vs. distal neck is 1.5 to 2.

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