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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

Prädiktoren für die Prognose nach perkutaner Mitralklappenreparatur mit dem MitraClip®-System / Predictors of outcome after percutaneous edge-to-edge mitral valve repair

Tichelbäcker, Tobias 23 September 2014 (has links)
No description available.
12

Die Rolle der intraoperativen Echokardiographie bei herzchirurgischen Operationen mit Schwerpunkt Mitralklappenrekonstruktion

Ender, Jörg 29 November 2012 (has links) (PDF)
Die vorliegende Arbeit beschreibt die Rolle der intraoperativen transösophagealen Echokardiografie während herzchirurgischer Eingriffe mit Schwerpunkt Mitralklappenrekonstruktion. Ziel ist die Beschreibung der Aufgaben und Möglichkeiten dieses Verfahrens im klinischen Alltag und das Aufzeigen möglicher neuer Einsatzgebiete, wie die bildgestützte Größenbestimmung der Annuloplastieringe. Die intraoperative Echokardiografie hat sich seit den Anfängen in den achtziger Jahren des letzten Jahrhunderts zu einem Standardverfahren während herzchirurgischer Eingriffe entwickelt. Sie dient zum einen zur kardialen Diagnostik und zum anderen als Monitorverfahren. Trotz in der Regel gut vordiagnostizierter Patienten führt die intraoperativ durchgeführte transösophageale Echokardiografie während herzchirurgischer Eingriffe nicht selten zur Diagnose vorher nicht bekannter Pathologien und somit zu einer Änderung im chirurgischen Vorgehen. Speziell während der Mitralklappenrekonstruktion ermöglicht diese Methode die Diagnostik und Lokalisation der pathologischen Segmente, die Bestätigung des Schweregrades und dem Erkennen möglicher Risikofaktoren. Hierfür ist jedoch eine umfassende, standardisierte Untersuchung notwendig. Der Einsatz moderner Operationstechniken, wie z.B. der kathetergestützten Implantation der Aortenklappe ohne Einsatz der Herz-Lungen-Maschine, ohne Eröffnung des Sternums, macht eine direkte visuelle Einschätzung der Herzfunktion unmöglich. Sowohl zur Evaluierung der Herzfunktion als auch zur Größenbestimmung der zu implantierenden Klappenprothesen ist ein bildgebendes Verfahren unabdingbar. Die dreidimensionale transösophageale Echokardiografie ermöglicht nun in Echtzeit die komplette Darstellung z.B. der Mitralklappe. Dies erleichtert nicht nur die Verständigung zwischen Echokardiographeur und Chirurgen bei der Darstellung der Befunde, sondern ermöglicht nun erstmals auch die bildgestützte Planung des operativen Vorgehens, wie, z.B. die Visualisierung und Größenbestimmung der zu implantierenden Annuloplastieringe, die als Computermodelle auf die dreidimensionale Darstellung der Mitralklappe projiziert werden können. In der postoperativen TEE-Untersuchung ist die Evaluierung des rekonstruierten Mitralklappenapparates, die Quantifizierung einer eventuell bestehenden residualen Mitralinsuffizienz, sowie deren genaue Lokalisation primäres Ziel. Weiterhin sollten iatrogen aufgetretene Komplikationen in einer umfassenden postoperativen TEE-Untersuchung diagnostiziert werden wie z.B. der Verschluss des Ramus circumflexus, Aortendissektion, etc. Zusammenfassend wird in dieser Habilitationsarbeit die Rolle der intraoperativen Echokardiografie bei herzchirurgischen Eingriffen dargestellt. Ein besonderer Schwerpunkt in dieser Arbeit ist die transösophageale Echokardiographie bei Mitralklappenoperationen im Hinblick auf die Darstellung der bestehenden Pathologie, der Quantifizierung der Mitralinsuffizienz und dem Erkennen bestehender Risikofaktoren präoperativ bzw das Erkennen der Komplikation postoperativ.
13

Mechanics of the mitral valve after surgical repair-an in vitro study

Padala, Sai Muralidhar 06 April 2010 (has links)
Mitral valve disease is widely prevalent among pediatric and adult population across the world, and it encompasses a spectrum of lesions which include congenital valve defects, degenerative valve lesions, and valve dysfunction due to secondary pathologies. Though replacement of the diseased mitral valves with artificial heart valves has been the standard of care until early 1990's, current trends have veered towards complete surgical repair. These trends are encouraging, but current repair techniques are plagued with lack of durability and high rates of failure within 10 years after repair. With increasing number of patients receiving mitral valve repair, there is now an immediate need to understand the mechanisms of repair failure, and assess the role of several clinical risk factors on valve repair. In this thesis, an in vitro pulsatile left heart simulator was developed to mimic the congenital and adult mitral valve pathological morphologies in normal porcine valves, and simulate the pathological valve hemodynamics and mechanics. Different surgical repair techniques were used to correct the valve lesions, and the post repair valve hemodynamics, mechanics and geometry were assessed using quantitative measurement techniques. The extent to which each repair restores physiological valve function and mechanics was assessed, and the impact of different pathological risk factors on repair failure mechanisms was investigated. It is expected that the knowledge from this thesis would play an important role in the evolution of mitral valve surgical repair, and guide the development of more effective and long-lasting heart valve repair technologies.
14

Fast Surgical Simulation to Improve Mitral Valve Repair

Tenenholtz, Neil Arturo 06 June 2014 (has links)
Mitral valve repair, the preferred method of treating mitral regurgitation, is a demanding surgical procedure consisting of the resection and approximation of valve tissue. Operating on an arrested heart, the clinician is forced to predict closed valve shape and the effect of surgical modifications. The valve's complex morphology makes this a difficult task, and as a result, the procedure is underperformed by less experienced surgeons in lieu of the simpler, less effective valve replacement. / Engineering and Applied Sciences
15

Non-Syndromic atrioventricular septal defects: a refined definition, associated risk factors, and prognostic factors for left atrioventricular valve replacement following primary repair

Patel, Sonali Subhashchandra 01 December 2010 (has links)
Congenital heart defects (CHDs) constitute a major proportion of clinically significant birth defects and are an important component of pediatric cardiovascular disease. Atrioventricular septal defects (AVSDs) include a range of anomalies characterized by atrial, ventricular, and atrioventricular (AV) valve defects. AVSDs commonly occur in the presence of a syndrome, most frequently Down syndrome; they also occur in isolation and are referred to as non-syndromic AVSDs (NSAVSDs). These studies were performed to evaluate for presence of an intermediate phenotype in parents and siblings of a child with a NSAVSD, risk factors associated with NSAVSDs, and prognostic risk factors for left AV valve replacement following primary repair of an AVSD. It was shown that the mean body surface area-standardized AV septal length (AVSL) was significantly shorter in the NSAVSD parents and siblings than in parents and siblings of syndromic AVSD case and control children. Using age- and gender-adjusted body surface area-standardized AVSL, it was determined that there was evidence for two component distributions in parents and siblings of NSAVSD children, suggesting the presence of an intermediate. Broadening the definition of AVSD to include those with a shortened AVSL may increase the power of genetic association and mapping studies to identify susceptibility genes. Risk factors associated with NSAVSD were examined using the 1997-2005 National Birth Defects Prevention Study database. Mothers who actively smoked or were exposed to passive smoke anytime from one month prior to pregnancy through the end of the first trimester were more likely to have an infant with a NSAVSD. There was a suggestive association between AVSDs and use of antibacterial, antifungal, and antiviral medications. Additional investigations are warranted to investigate associations with specific medications as well as to uncover possible gene-environment interaction effects that may modify these risks in order to develop improved primary prevention strategies. Using the Pediatric Cardiac Care Consortium database, factors associated with time to first reoperation and time to replacement following primary AVSD repair were evaluated. Type of AVSD repair, closure of the mitral valve cleft, moderate to severe postoperative left AV valve regurgitation, and presence of postoperative complete heart block were associated with earlier time to reoperation after adjusting for age and weight at AVSD repair. Down syndrome and presence of postoperative mitral stenosis were associated with earlier time to replacement. Prognostic risk factors following left AV valve replacement in children who had previously undergone AVSD repair were also identified. A prosthetic valve size to body weight ratio of greater than 3 and the presence of Down syndrome were identified as predictors of in-hospital death following left AV valve replacement. By adding to our knowledge of the AVSD familial and environmental risk factors from these studies, we will be able to (1) improve genetic counseling, (2) identify other family members for genetic testing, (3) begin to devise primary prevention strategies, and (4) improve treatment modalities. By recognizing prognostic factors which influence survival, optimal patient care can be devised which will not only improve treatment modalities, but also long-term survival.
16

A systemic Review: Are Outcomes of Aortic Valve Repair ‘A Beneficial alternative’ for patients with Aortic Valve Insufficiency?

Malik, Samreen Mohammad January 2020 (has links)
IntroductionThe young adult patients with aortic valve insufficiency undergo aortic valve replacement (AVR) and are forced to take anticoagulation medications for the rest of life due to prosthetic valve. This leads to many post-operative complications and drastic outcomes. Whereas, the in-vogue alternative of aortic valve repair (AVr) is available and a lot more beneficial as well.Especially considering the surgeon’s skills for selected repair procedure, selectively chosen patient with mild to moderate grades of aortic valve insufficiency and no significant comorbidities present for at least five (5) years or longer time. AimThe aim of this study was to affirm ‘if all kind of outcomes of aortic valve repair are beneficial alternative to aortic valve replacement (AVR) for the patients suffering from aortic valve insufficiency for at least five (5) years or longer time. Material and MethodsInternet search using standard key words of ‘Aortic Valve Repair and Outcomes’ was used to find both white literature (officially published literature) and grey literature (unpublished or ongoing study/literature) with human, adult, English language and studies published after January 1st 2007 as limitations. Inclusion criteria was adult patients with aortic insufficiency with aortic valve repair as intervention with outcomes at least greater than five (5) years were considered. All the data was extracted using Microsoft excel for windows and was analyzed using GraphPad Prisma. Results20 studies comprising of 5369 patients were included in this systemic review, which included 2 randomized control trails, 7 clinical prospective studies, 8 retrospective studies and 3 observational studies. ConclusionThis study suggests that aortic valve repair is a beneficial alternative available for younger adults suffering from aortic valve insufficiency in longer time.
17

Prädiktion der linksventrikulären Funktion nach Mitralklappenrekonstruktion unter Verwendung des präoperativen Tei Index

Gröger, Steffen 04 May 2016 (has links) (PDF)
Die chirurgische Mitralklappenrekonstruktion (MKR) ist der konservativen Therapie bei signifikanter Mitralklappeninsuffizienz (MI) überlegen. Bisher fehlen sensitive präoperative Parameter zur Detektion latenter linksventrikulärer Funktionsstörungen. Aufgrund der pathophysiologisch bedingten Nachlastreduktion und Vorlaststeigerung bei MI bergen die konventionell verwendeten Ejektionsindices, Ejektionsfraktion (EF) und Fractional Area Change (FAC), die Gefahr der Überschätzung der effektiven Pumpfunktion des linken Ventrikels (LV). Der dopplersonographisch erhobene Tei Index gilt als ein Marker globaler myokardialer Funktion. Ziel der vorliegenden Studie war es, mit dem Tei Index (bzw. dem Myokardialen Performance Index, MPI) einen sensitiveren präoperativen Parameter zur Prädiktion der postoperativen linksventrikulären Funktion zu finden. Hierzu wurden im Rahmen einer prospektiven klinischen Studie 130 Patienten mit signifikanter MI am Herzzentrum Leipzig entsprechend den ASE/SCA Leitlinien vor und nach kardiopulmonaler Bypass-Operation mittels transösophagealer echokardiographischer (TEE) Bildgebung untersucht. Die Quantifizierung der MI erfolgte durch Messung der Vena contracta (VC). Die FAC wurde in der transgastrischen midpapillären kurzen Achse und die EF im midösophagealen Zwei- sowie Vier-Kammer-Blick erfasst. Die Zeitintervalle zur Berechnung des Tei Index wurden im tiefen transgastrischen und midösophagealen Vier-Kammer-Blick erfasst. Eine statistische Korrelation zwischen präoperativen Tei Index und postoperativer EF und FAC konnte zur Validierung unserer Hypothese nicht detektiert werden. Folgend kann der Tei Index nicht als Prädiktor der effektiven linksventrikulären Funktion vor MKR gewertet werden.
18

Der Einfluss der Lernkurve auf die Ergebnisse der perkutanen Mitralklappenrekonstruktion mit MitraClip® in einer unizentrischen Kohorte von 75 chirurgischen Hochrisikopatienten / Impact of the learning curve on outcomes after percutaneous mitral valve repair with MitraClip® and lessons learned after the firtst 75 consecutive patients

Weicken, Ninja Maria 19 June 2012 (has links)
No description available.
19

Barlow’s Mitral Valve Disease: A Comparison of Neochordal (Loop) and Edge-To-Edge (Alfieri) Minimally Invasive Repair Techniques

da Rocha e Silva, Jaqueline Grace 08 December 2015 (has links)
Background. Barlow’s mitral valve (MV) disease re- mains a surgical challenge. We compared short- and medium-term outcomes of neochordal (“loop”) versus edge-to-edge (“Alfieri”) minimally invasive MV repair in patients with Barlow’s disease. Methods. From January 2009 to April 2014, 123 consecutive patients with Barlow’s disease (defined as bileaflet billowing or prolapse [or both], excessive leaflet tissue, and annular dilatation with or without calcifica- tion) underwent minimally invasive MV operations for severe mitral regurgitation (MR) at our institution. Three patients (2.4%) underwent MV replacement during the study period and were excluded from subsequent anal- ysis. The loop MV repair technique was used in 68 pa- tients (55.3%) and an edge-to-edge repair was performed in 44 patients (35.8%). Patients who underwent a combi- nation of these 2 techniques (n [ 8 [6.5%]) were excluded. The median age was 48 years, and 62.5% of patients were men. Concomitant procedures included closure of a patent foramen ovale or atrial septal defect (n [ 19), tricuspid valve repair (n [ 5), and atrial fibril- lation ablation (n [ 15). Follow-up was performed 24.7 ± 17 months postoperatively and was 98% complete. Results. No deaths occurred perioperatively or during follow-up. Aortic cross-clamp time (64.1 ± 17.6 minutes versus 95.9 ± 29.5 minutes) and cardiopulmonary bypass (CPB) time (110.0 ± 24.2 minutes versus 146.4 ± 39.1 mi- nutes) were significantly shorter (p < 0.001) in patients who received edge-to-edge repair. Although patients who underwent edge-to-edge repair received a larger annulo- plasty ring (38.6 ± 1.5 mm versus 35.8 ± 2.7 mm; p < 0.001), the early postoperative resting mean gradients were higher(3.3±1.2mmHgversus2.6±1.2mmHg;p[ 0.007) and the mitral orifice area tended to be smaller in this group (2.8 ± 0.7 cm2 versus 3.0 ± 0.7 cm2; p [ 0.06). The amount of residual MR was similar between groups (0.3 ± 0.6 versus 0.6 ± 1.0 for edge-to-edge versus loop procedures, respectively; p [ 0.08). More than mild MR requiring early MV reoperation was present in 3 patients who underwent loop procedures (4.4%) and in no patients who had edge-to-edge procedures (p [ 0.51). During follow-up, 2 patients (1 in each group) required MV replacement for severe MR. The 4-year freedom from MV reoperation was 92.8% ± 5.0% in the Alfieri group compared with 90.9% ± 4.6% in the loop group (p [ 0.94). Conclusions. Minimally invasive MV repair can be accomplished with excellent early and medium-term outcomes in patients with Barlow’s disease. The edge- to-edge (Alfieri) repair can be performed with reduced operative times when compared with the loop technique, but it results in mildly increased transvalvular gradients and mildly decreased valve opening areas without any difference in residual MR.
20

Prädiktion der linksventrikulären Funktion nach Mitralklappenrekonstruktion unter Verwendung des präoperativen Tei Index

Gröger, Steffen 19 April 2016 (has links)
Die chirurgische Mitralklappenrekonstruktion (MKR) ist der konservativen Therapie bei signifikanter Mitralklappeninsuffizienz (MI) überlegen. Bisher fehlen sensitive präoperative Parameter zur Detektion latenter linksventrikulärer Funktionsstörungen. Aufgrund der pathophysiologisch bedingten Nachlastreduktion und Vorlaststeigerung bei MI bergen die konventionell verwendeten Ejektionsindices, Ejektionsfraktion (EF) und Fractional Area Change (FAC), die Gefahr der Überschätzung der effektiven Pumpfunktion des linken Ventrikels (LV). Der dopplersonographisch erhobene Tei Index gilt als ein Marker globaler myokardialer Funktion. Ziel der vorliegenden Studie war es, mit dem Tei Index (bzw. dem Myokardialen Performance Index, MPI) einen sensitiveren präoperativen Parameter zur Prädiktion der postoperativen linksventrikulären Funktion zu finden. Hierzu wurden im Rahmen einer prospektiven klinischen Studie 130 Patienten mit signifikanter MI am Herzzentrum Leipzig entsprechend den ASE/SCA Leitlinien vor und nach kardiopulmonaler Bypass-Operation mittels transösophagealer echokardiographischer (TEE) Bildgebung untersucht. Die Quantifizierung der MI erfolgte durch Messung der Vena contracta (VC). Die FAC wurde in der transgastrischen midpapillären kurzen Achse und die EF im midösophagealen Zwei- sowie Vier-Kammer-Blick erfasst. Die Zeitintervalle zur Berechnung des Tei Index wurden im tiefen transgastrischen und midösophagealen Vier-Kammer-Blick erfasst. Eine statistische Korrelation zwischen präoperativen Tei Index und postoperativer EF und FAC konnte zur Validierung unserer Hypothese nicht detektiert werden. Folgend kann der Tei Index nicht als Prädiktor der effektiven linksventrikulären Funktion vor MKR gewertet werden.

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