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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.
41

Use of autologous auricular chondrocytes for lining left ventricular assist devices

Rosenstrauch, Doreen 21 June 2004 (has links)
Hintergrund: Elastischer Ohrknorpel ist eine potentielle Quelle fuer autologe Zellen um die luminalen Oberflaechen von links ventrikularen assist systemen (LVAD''s) zu besiedeln zu dem Zweck die Biokompatibilitaet dieser Systeme zu verbessern. Wir prueften dieses Potential der Ohrknorpelzellen in vitro und in vivo in einem Tiermodel (Kalb). Methoden: In vitro, Elastischer Knorpel wurde von dem Ohr eines Kalbes unter Lokalanaesthesie gewonnen, isoliert, und in Gewebekultur gezuechtet. Chondrocytes wurden immunocytochemisch analysiert, transferriert in Zellkulturmedium, zweimal umgesetzt, und auf die blutkontaktierenden, luminalen Oberflaechen von vier LVAD''s (HeartMate(R); Thermo Cardiosystems, Inc., Woburn, MA) gesiedelt. Die beschichteten Zelloberflaechen wurden preconditioniert unter Flussbedingungen in vitro, um die Zellhaftung an den luminalen Oberflaechen der LVAD''s zu beguenstigen. Die Effiezienz der Zellbesiedelung und der kumulative Zellverlust unter Flussbedingungen in vitro wurden quantifiziert. In vivo, eine der vier chondrocyte-beschichteten und preconditionierten LVAD''s wurde in das Kalb implantiert, welches urspruenglich Ohrknorpelspender diente. Das LVAD wurde fuer sieben Tage betrieben, dann explantiert und pathologisch und histologisch evaluiert unter der Benutzung eines Scanningelektronenmikroskopes und eines Transmissionelektronenmikroskopes. Resultate: Die luminalen Oberflaechen von vier LVAD''s wurden mit autologen Ohrknorpelzellen besiedelt. Die Effiezienz der Zellbesiedelung betrug 95.11± 4.23% (n = 4). Der kumulative Zellverlust unter Flussbedingungen in vitro war geringer als 12% (n = 4). Nach sieben Tagen der in vivo Implantation zeigten die luminalen Oberflaechen des implantierten LVAD eine intakte, fest haftende Zellbesiedelung. Es wurden keine Thromboembolien waehrend der Nekropsie festgestellt. Schlussfolgerungen: Ohrknorpel stellt eine einfach und schnell erreichbare Quelle fuer autologe Ohrknorpelzellen dar, dessen Collagen Typ II und andere wichtige Bestandteile der extrazellulaeren Matrix sie dazu befaehigt, fest an den luminalen Oberflaechen der LVAD''s zu haften. Die hier beschriebene einfache Methode der Knorpelgewinnung und der Zellisolierung kann benutzt werden, um eine autologe Zellbeschichtung von LVAD''s und anderen implantierbaren kardiovaskulaeren Systemen vorzunehmen mit dem Ziel die Biokompatibilitaet dieser zu verbessern. Unsere erfolgreiche Feasibilitystudie in einem Kalbmodel fordert weitere in vivo Studien. / Background: Auricular elastic cartilage is a potential source of autologous cells for lining the luminal surfaces of left ventricular assist devices (LVAD''s) to improve long-term biocompatibility. We evaluated this potential in vitro and in vivo in a calf model. Methods: In vitro, auricular cartilage was harvested from the anesthetized ear of a calf, isolated, and cultured on tissue culture dishes. Primary chondrocytes were typed by immunocytochemistry, transferred into culture media, passaged twice, and seeded onto the blood-contacting luminal surfaces of four LVAD''s (HeartMate(R); Thermo Cardiosystems, Inc., Woburn, MA). The seeded cell linings were preconditioned under flow conditions in vitro to promote cell adhesion to the luminal surfaces. Seeding efficiency and cumulative cell loss under flow conditions in vitro were quantitated. In vivo, one of the four preconditioned, autologous chondrocyte-lined LVAD''s was implanted into the tissue-donor calf; run for 7 days; explanted; and finally evaluated grossly, by scanning electron microscopy, and by transmission electron microscopy. Results: Autologous chondrocytes were seeded onto the luminal surfaces of the four LVAD''s. The seeding efficiency was 95.11± 4.23% (n = 4). Cumulative cell loss during preconditioning under flow conditions in vitro did not exceed 12% (n = 4). After 7 days of in vivo implantation, the luminal surfaces of the implanted LVAD demonstrated an intact, strongly adherent cellular lining. There was no evidence of thromboembolic events at necropsy. Conclusions: Auricular elastic cartilage is a ready and easily accessible source of chondrocytes whose ability to produce collagen II and other important extracellular matrix constituents allows them to adhere strongly to the luminal surfaces of LVAD''s. The simple method of isolating and expanding auricular chondrocytes presented here could be used to provide autologous cell linings for LVAD''s and other cardiovascular devices to improve their long-term biocompatibility. Our successful short-term feasibility study in a calf model warrants further study in vivo.
42

Příspěvek vyšetření BNP ke zpřesnění prognózy nemocných s pokročilým srdečním selháním / Contribution of BNP to prognostic stratification of patients with advanced heart failure.

Hegarová, Markéta January 2017 (has links)
Plasma levels of B-type natriuretic peptide (BNP) are a strong and independent predictor of prognosis in patients with advanced heart failure (CHF). However, the importance of this biomarker has been documented only in CHF of common causes such as dilated or ischemic cardiomyopathy. We hypothesized that BNP can serve as a strong predictor of end-stage CHF in group of patients with advanced CHF due to congenital heart disease (CHD) with the right ventricle in systemic position (SRV). The second hypothesis was that BNP monitoring in patients with implanted left ventricular assist device (LVAD) Heart Mate II could detect serious complications which negatively affect prognosis. We performed a retrospective analysis in 28 consecutive patients with severe systolic dysfunction of the SRV (ejection fraction 23 ± 6%) evaluated as heart transplant (HTx) candidates between May 2007 and October 2014. During a median follow-up of 29 months (interquartile range, 9-50), 14 pts reached primary endpoints of the study (death, urgent HTx, and LVAD implantation). We have considered these events equivalent to end-stage CHF. Using ROC analysis, we identified the first measured value of BNP as the strongest predictor of prognosis with the area under the curve (AUC) of 1.00, followed by the New York Heart Association...
43

Vířivé čerpadlo jako možná srdeční náhrada / Vortex pump as a possible heart replacement

Coufalík, Martin January 2017 (has links)
The diploma thesis deals with the issue of artificial hearts and ventricular assist devices. The theoretical part describes the heart and its function. Blood is characterized in terms of rheological behavior and the possible criteria for hemolysis are discussed. The following section describes the most commonly used ventricular assist devices, with emphasis on the use of the regenerative pump, including its components. In the practical part, an experimental analysis of two pumps (COV 43 and COV 23) is performed. Furthermore, non-dimensional characteristics of the pumps are constructed using the laws of similarity. In the computational part, the CFD analysis of the regenerative pump is performed by means of stationary and transient calculation. The results are compared with the experimental findings and based on the results, the impeller of regenerative pump was modified.
44

Incidence and Predictor Variables of Pressure Injuries in Patients Undergoing Ventricular Assist Device and Total Artificial Heart Surgeries: An Eight-Year Retrospective Review

Brindle, Christopher T 01 January 2019 (has links)
BACKGROUND Cardiac surgery patients have some of the highest reported incidence and prevalence of pressure injuries (PI). A growing subset of cardiac surgery include patients with end-stage heart failure who undergo ventricular assist device (VAD) or total artificial heart (TAH) surgery. The risk of PI and their natural history of development in this population are unknown and the specific risk factors for PI development remain unexplored. OBJECTIVES To perform a systematic review of the literature to identify the incidence and risk factors of PI development in patients undergoing VAD-TAH surgery and thereby inform study design and variables in an eight-year retrospective study of all patients undergoing VAD-TAH surgery at a large academic university medical center. METHODS The preferred reporting items for systematic reviews and meta-analyses or PRISMA statement guided this systematic review. Quality of evidence was determined using the Johns Hopkins Nursing Evidence-Based Practice Rating Scale. Two reviewers independently appraised manuscripts matching the eligibility criteria for study inclusion. Four databases including PubMed, CINAHL, Web of Science, Google Scholar, and hand searches of journals based on reference lists from included studies were utilized. Initial results of this primary search revealed zero studies that met inclusion and this search methodology was confirmed by medical librarian consultation. Therefore, a follow up retrospective study was necessary to identify incidence of PI in the VAD-TAH population. However, a secondary search, dropping keywords of VAD-TAH and instead focusing on studies of on-pump cardiac surgery and mixed surgical studies where cardiac surgery patients were included, was conducted to establish variables to guide a retrospective study of all VAD-TAH surgeries between 2010-2018. The retrospective study evaluated the incidence of pressure ulcers by case, patient and incidence density for each of the respective 1000 patient days during the study period. Univariate statistics are reported by four different VAD-TAH devices. Variables significant in bivariate analysis were entered in a stepwise logistic regression model. RESULTS In the systematic review, 312 articles were identified from the databases with eight additional articles from hand searches. Following abstract review, 208 were excluded for not meeting inclusion criteria or study quality metrics. 77 articles were read in full, with 61 excluded, leaving 16 articles for inclusion. 31 risk factors were identified for PI development in on-pump cardiac surgery patients with 11 risk factors which were identified as significant in multivariate analysis for inclusion in the retrospective study.
45

Erste Erfahrungen mit der Micro-Diagonalpumpe Deltastream® der Firma Medos (Helmholtz Institut Aachen) als linksventrikulärem Herzunterstützungssystem (LVAD) mit pulsatiler und laminarer Perfusion am Schafsmodell über sieben Tage. / Initial experience with the Micro Diagonal Pump Deltastream® of Medos, (Helmholtz Institute Aachen) a left ventricular cardiac assist device (LVAD) with pulsatile and laminar perfusion in a sheep about seven days.

Tylla, Alfred 09 January 2012 (has links)
No description available.
46

Časná pooperační péče u pacienta s levostrannou mechanickou srdeční podporou HeartMate II / Early postoperative care of the patient with the left ventricular assist device HeartMate II

Malá, Irena January 2013 (has links)
Author's name: Bc. Irena Malá School: Charles university, Prague 1st Faculty of Medicine Institut of Theory and Practice of Nursing Vídeňská 800, 140 59 Prague 4 - Krč Program: Health Care Administration Title: Early postoperative care of the patient with the left ventricular assist device HeartMate II Diploma thesis supervisor: PhDr. Hocková Jana, PhD. Number of pages: 170 Number of attachments: 41 Year: 2013 Key words: early postoperative care, hypotermia, blood transfusion, fluid resuscitation, perioperative cardiovascular dysfunction, pharmacologic support, ventricular assist device HeartMateII, monitoration, device, cardiac arrhythmias, ventilation management, postoperative anticoagulation, glycemic kontrol, renal insufficiency, nutrition, nursing, complications, physiotherapy, psychological aspects The occurrence of the heart failure is similar to an epidemic with high mortality. This fact, together with stagnate or even decreasing number of suitable donors, led to a need of replacing the heart pump activity with an artificial one. Mechanical cardiac support systems are sophisticated devices that are able to support a certain period of time or completely replace the function of the heart as a pump. The indications implantation of mechanical cardiac support is significant symptomatic heart...

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