Littérature scientifique sur le sujet « Aortic valve stenosis (AVS) »
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Articles de revues sur le sujet "Aortic valve stenosis (AVS)"
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Frank, Rolf Dario, Regina Lanzmich, Philipp K. Haager et Ulrich Budde. « Severe Aortic Valve Stenosis ». Clinical and Applied Thrombosis/Hemostasis 23, no 3 (4 août 2016) : 229–34. http://dx.doi.org/10.1177/1076029616660759.
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Aortic valve stenosis (AVS) is the most common valve disease in adults. Severe forms are associated with acquired von Willebrand syndrome (aVWS) with loss of the largest von Willebrand factor (VWF) multimers. Diagnostic gold standard is the VWF multimer analysis. Valve replacement rapidly restores the VWF structure. Uncertainty exists if this effect is permanent and how functional VWF assays perform compared with multimer analysis. We studied 21 consecutive patients with severe AVS before and 6 to 18 months after valve surgery and compared them with 14 controls without valve disease referred for coronary angiography. The VWF multimers, VWF antigen (VWF:Ag), VWF collagen binding capacity (VWF:CB), VWF:CB/VWF:Ag ratio, in vitro bleeding time (PFA-100), factor VIII coagulation activity (FVIII:C), and VWF ristocetin cofactor activity (VWF:RCo) were determined. In all patients with AVS, the large VWF multimers were strongly reduced (56 ± 13% of normal plasma); all controls had normal multimers. The PFA-100 collagen/ADP closure times (coll/ADP CT) were prolonged in patients with AVS compared with the controls (175 ± 56 seconds vs 86 ± 14 seconds, P < .001). The VWF:CB/VWF:Ag ratio was pathological in 20 of the 21 patients but normal in controls. After surgery, the multimers normalized in all patients and coll/ADP CT shortened (pre 184 ± 65 seconds vs post 102 ± 22 seconds; P < .001). The VWF:CB/VWF:Ag ratio strongly improved ( P < .001) and normalized in 14 of 17 patients. In conclusion, all consecutive patients with severe AVS had an aVWS. The combination of coll/ADP CT and VWF:CB/VWF:Ag ratio detected the aVWS in all patients. More than 6 months after valve replacement, the VWF multimers were still normalized in all patients indicating a permanent cure of the aVWS.
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Rakhmanov, Yeltay, Paolo Enrico Maltese, Alessandra Zulian, Stefano Paolacci, Tommaso Beccari, Munis Dundar et Matteo Bertelli. « Genetic testing for aortic valve stenosis ». EuroBiotech Journal 2, s1 (1 septembre 2018) : 61–63. http://dx.doi.org/10.2478/ebtj-2018-0040.
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Abstract Aortic valve stenosis (AVS) is a congenital aortic defect in which the aortic lumen narrows due to thickening or calcification of the aortic valve without obstructing left ventricular outflow. Depending on the site of obstruction, AVS is classified as valvular, sub-valvular or supra-valvular. The prevalence of AVS is about 3% and increases with age. One in eight persons over the age of 75 years has moderate or severe AVS. AVS has autosomal dominant inheritance. It can be associated with mutations in the following genes: NOTCH1, SMAD6, SMAD4, and ELN. This Utility Gene Test was developed on the basis of the analysis of the literature and existing diagnostic protocols. It is useful for confirming diagnosis, as well as for differential diagnosis, couple risk assessment and access to clinical trials, when available.
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Sossong, Verena, Thomas Helbing, Friedhelm Beyersdorf, Manfred Olschewski, Christoph Bode, Philipp Diehl, Ferenc Nagy et Martin Moser. « Increased levels of circulating microparticles in patients with severe aortic valve stenosis ». Thrombosis and Haemostasis 99, no 04 (2008) : 711–19. http://dx.doi.org/10.1160/th07-05-0334.
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SummaryThe mechanisms of the progression of aortic valve stenosis are unknown. The involvement of mononuclear cells and of chronic systemic inflammation has been suggested by analysis of pathological specimens. We hypothesize that shear stress caused by the constricted aortic orifice contributes to systemic proinflammation by activation of circulating blood cells and thereby generation of microparticles. Using flow cytometry we analyzed 22 patients with severe aortic valve stenosis (AVS) and 18 patient controls for the generation of circulating microparticles from platelet-(PMPs: CD31+/CD61+ or CD62P+), leukocyte-(LMPs: CD11b+) and endothelial cell (EMPs: CD62E+) origin. Apart from the constricted valve orifice groups were similar. PMPs were increased in AVS patients and their number correlated with valvular shear stress. Monocytes were activated in AVS patients, an observation that was also reflected by increased numbers of LMPs and by the detection of PMP-monocyte conjugates. Furthermore, EMPs reflecting the activation of endothelial cells but also conferring systemic inflammatory activity were increased in AVS patients and correlated with the number of activated monocytes. In conclusion, we show that AVS is accompanied by increased levels of microparticles and that shear stress can induce the formation of microparticles. Based on our results and histologic findings of other investigators the speculation that shear stress related to aortic valve stenosis induces a vicious circle including the generation of PMPs, the subsequent activation of monocytes and LMPs and finally the activation of endothelial cells contributing to the progress of aortic valve stenosis appears to be justified.
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Oostveen, Reindert F., Yannick Kaiser, Erik S. G. Stroes et Hein J. Verberne. « Molecular Imaging of Aortic Valve Stenosis with Positron Emission Tomography ». Pharmaceuticals 15, no 7 (30 juin 2022) : 812. http://dx.doi.org/10.3390/ph15070812.
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Aortic valve stenosis (AVS) is an increasingly prevalent disease in our aging population. Although multiple risk factors for AVS have been elucidated, medical therapies capable of slowing down disease progression remain unavailable. Molecular imaging technologies are opening up avenues for the non-invasive assessment of disease progression, allowing the assessment of (early) medical interventions. This review will focus on the role of positron emission tomography of the aortic valve with 18F-fluorodeoxyglucose and 18F-sodium fluoride but will also shed light on novel tracers which have potential in AVS, ranging from the healthy aortic valve to end-stage valvular disease.
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Schnitzler, Johan G., Lubna Ali, Anouk G. Groenen, Yannick Kaiser et Jeffrey Kroon. « Lipoprotein(a) as Orchestrator of Calcific Aortic Valve Stenosis ». Biomolecules 9, no 12 (21 novembre 2019) : 760. http://dx.doi.org/10.3390/biom9120760.
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Aortic valve stenosis (AVS) is the most prevalent valvular heart disease in the Western World with exponentially increased incidence with age. If left untreated, the yearly mortality rates increase up to 25%. Currently, no effective pharmacological interventions have been established to treat or prevent AVS. The only treatment modality so far is surgical or transcatheter aortic valve replacement (AVR). Lipoprotein(a) [Lp(a)] has been implicated as a pivotal player in the pathophysiology of calcification of the valves. Patients with elevated levels of Lp(a) have a higher risk of hospitalization or mortality due to the presence of AVS. Multiple studies indicated Lp(a) as a likely causal and independent risk factor for AVS. This review discusses the most important findings and mechanisms related to Lp(a) and AVS in detail. During the progression of AVS, Lp(a) enters the aortic valve tissue at damaged sites of the valves. Subsequently, autotaxin converts lysophosphatidylcholine in lysophosphatidic acid (LysoPA) which in turn acts as a ligand for the LysoPA receptor. This triggers a nuclear factor-κB cascade leading to increased transcripts of interleukin 6, bone morphogenetic protein 2, and runt-related transcription factor 2. This progresses to the actual calcification of the valves through production of alkaline phosphatase and calcium depositions. Furthermore, this review briefly mentions potentially interesting therapies that may play a role in the treatment or prevention of AVS in the near future.
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Bardelli, Moreno, Monica Cavressi, Giulia Furlanis, Bruno Pinamonti, Mariafontana Leone, Stefano Albani, Renata Korcova, Bruno Fabris et Gianfranco Sinagra. « Relationship between aortic valve stenosis and the hemodynamic pattern in the renal circulation, and restoration of the flow wave profile after correction of the valvular defect ». Journal of International Medical Research 48, no 9 (septembre 2020) : 030006052095690. http://dx.doi.org/10.1177/0300060520956907.
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Objective The index of maximal systolic acceleration ([AImax]: maximal systolic acceleration of the Doppler waveform divided by peak systolic velocity) shows diagnostic accuracy in screening of renal artery stenosis. This study aimed to determine whether an upstream factor of resistance, such as aortic valve stenosis (AVS), can affect Doppler parameters detected in the peripheral arteries. Methods In this prospective study, we measured the AImax in non-stenotic renal interlobar arteries of 62 patients with AVS. Patients were divided into three groups on the basis of severity of valvulopathy as follows: mild-to-moderate AVS (M-AVS; n = 24), intermediate AVS (I-AVS; n = 15), and severe AVS (S-AVS; n = 23) based on Nishimura’s criteria. Results The AImax in the renal parenchymal arteries was significantly lower in the S-AVS group (8.9 ± 3.6 s−1) than in the M-AVS (15.3 ± 3.8 s−1) and I-AVS groups (16.7 ± 5.2 s−1). The AImax was positively correlated with the aortic valve area and inversely correlated with the tranvalvular aortic pressure gradient. After aortic valve replacement, the AImax significantly increased from 10.7 ± 4.0 s−1 at baseline to 19.3 ± 4.4 s−1. Conclusions Proximal resistance can lead to diagnostic bias of Doppler parameters that are applied in the diagnosis of peripheral vasculopathies, particularly in renal artery stenosis.
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Artiach, Gonzalo, Miguel Carracedo, Till Seime, Oscar Plunde, Andres Laguna-Fernandez, Ljubica Matic, Anders Franco-Cereceda et Magnus Bäck. « Proteoglycan 4 is Increased in Human Calcified Aortic Valves and Enhances Valvular Interstitial Cell Calcification ». Cells 9, no 3 (11 mars 2020) : 684. http://dx.doi.org/10.3390/cells9030684.
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Aortic valve stenosis (AVS), a consequence of increased fibrosis and calcification of the aortic valve leaflets, causes progressive narrowing of the aortic valve. Proteoglycans, structural components of the aortic valve, accumulate in regions with fibrosis and moderate calcification. Particularly, proteoglycan 4 (PRG4) has been identified in fibrotic parts of aortic valves. However, the role of PRG4 in the context of AVS and aortic valve calcification has not yet been determined. Here, transcriptomics, histology, and immunohistochemistry were performed in human aortic valves from patients undergoing aortic valve replacement. Human valve interstitial cells (VICs) were used for calcification experiments and RNA expression analysis. PRG4 was significantly upregulated in thickened and calcified regions of aortic valves compared with healthy regions. In addition, mRNA levels of PRG4 positively associated with mRNA for proteins involved in cardiovascular calcification. Treatment of VICs with recombinant human PRG4 enhanced phosphate-induced calcification and increased the mRNA expression of bone morphogenetic protein 2 and the runt-related transcription factor 2. In summary, PRG4 was upregulated in the development of AVS and promoted VIC osteogenic differentiation and calcification. These results suggest that an altered valve leaflet proteoglycan composition may play a role in the progression of AVS.
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Ferrari, V., C. Mazzanti et L. De Biase. « RELATION BETWEEN CALCIUM METABOLISM AND DEVELOPMENT OF AORTIC VALVE STENOSIS ». European Heart Journal Supplements 26, Supplement_2 (avril 2024) : ii209. http://dx.doi.org/10.1093/eurheartjsupp/suae036.501.
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Abstract The role of calcium metabolism in the development of degenerative Aortic Valve Stenosis (AVS) is not completely understood. Valvular cell modifications and passive calcification can be both involved in the diseases. Vitamin D (Vit D) and Parathyroid Hormone (PTH) are important factor in calcium regulation and data on their modification in AVS are scanty. Their potential role in AVS prevention is not yet identified. Osteocalcin can be considered a marker of calcification and its potential usefulness in identification of patient at risk for AVS was not studied. In order to correlate calcium metabolism to AVS development we have studied PTH, Vit D and Osteocalcin in a population of patients with AVS. We recruited 100 patients admitted in our Cardiac Surgery Unit for AVS confirmed by electrocardiogram, echocardiogram and hemodynamic evaluation. Subjects with rheumatic or congenital valvulopathy and infectious endocarditis were excluded from the study. Calcium, phosphorus, calcium–phosphorus ratio (Ca/P ratio), PTH, Vit D, renal function and osteocalcin were measured in each patient. In our population, 93.5% of patients had low levels of Vit D (<30 ng / ml), 42.4% had elevated levels of PTH (>38.4 pg / ml) and 28% had low levels of osteocalcin (<14 ng / ml). 87% of the population had normal calcium levels (8.4–10.2 mg / dl) and 93.3% had normal levels of phosphoremia (2.7–4.5 mg / dl). Defining as normal a Ca/P ratio between 1.5 and 2.5, 60.7% of our population had high levels of Ca/P. In conclusion, our findings suggest that patients suffering from AVS have abnormal levels of factors involved in the regulation of calcium metabolism. Some factors can be target for preventive therapies.
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Krzesińska, Aleksandra, Maria Nowak, Agnieszka Mickiewicz, Gabriela Chyła-Danił, Agnieszka Ćwiklińska, Olga M. Koper-Lenkiewicz, Joanna Kamińska et al. « Lipoprotein(a) As a Potential Predictive Factor for Earlier Aortic Valve Replacement in Patients with Bicuspid Aortic Valve ». Biomedicines 11, no 7 (25 juin 2023) : 1823. http://dx.doi.org/10.3390/biomedicines11071823.
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Bicuspid aortic valve (BAV) affects 0.5–2% of the general population and constitutes the major cause of severe aortic valve stenosis (AVS) in individuals ≤70 years. The aim of the present study was to evaluate the parameters that may provide information about the risk of AVS developing in BAV patients, with particular emphasis on lipoprotein(a) (Lp(a)), which is a well-recognized risk factor for stenosis in the general population. We also analyzed the impact of autotaxin (ATX) and interleukin-6 (IL-6) as parameters potentially related to the pathomechanism of Lp(a) action. We found that high Lp(a) levels (>50 mg/dL) occurred significantly more frequently in patients with AVS than in patients without AVS, both in the group below and above 45 years of age (p = 0.036 and p = 0.033, respectively). Elevated Lp(a) levels were also strictly associated with the need for aortic valve replacement (AVR) at a younger age (p = 0.016). However, the Lp(a) concentration did not differ significantly between patients with and without AVS. Similarly, we observed no differences in ATX between the analyzed patient groups, and both ATX activity and concentration correlated significantly with Lp(a) level (R = 0.465, p < 0.001 and R = 0.599, p < 0.001, respectively). We revealed a significantly higher concentration of IL-6 in young patients with AVS. However, this observation was not confirmed in the group of patients over 45 years of age. We also did not observe a significant correlation between IL-6 and Lp(a) or between CRP and Lp(a) in any of the analyzed groups of BAV patients. Our results demonstrate that a high level of Lp(a), greater than 50 mg/dL, may be a significant predictive factor for earlier AVR. Lp(a)-related parameters, such as ATX and IL-6, may be valuable in providing information about the additional cardiovascular risks associated with developing AVS.
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Torres-Arellano, José M., Juan C. Echeverría, Nydia Ávila-Vanzzini, Rashidi Springall, Andrea Toledo, Oscar Infante, Rafael Bojalil, Jorge E. Cossío-Aranda, Erika Fajardo et Claudia Lerma. « Cardiac Autonomic Response to Active Standing in Calcific Aortic Valve Stenosis ». Journal of Clinical Medicine 10, no 9 (7 mai 2021) : 2004. http://dx.doi.org/10.3390/jcm10092004.
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Aortic stenosis is a progressive heart valve disorder characterized by calcification of the leaflets. Heart rate variability (HRV) analysis has been proposed for assessing the heart response to autonomic activity, which is documented to be altered in different cardiac diseases. The objective of the study was to evaluate changes of HRV in patients with aortic stenosis by an active standing challenge. Twenty-two volunteers without alterations in the aortic valve (NAV) and twenty-five patients diagnosed with moderate and severe calcific aortic valve stenosis (AVS) participated in this cross-sectional study. Ten minute electrocardiograms were performed in a supine position and in active standing positions afterwards, to obtain temporal, spectral, and scaling HRV indices: mean value of all NN intervals (meanNN), low-frequency (LF) and high-frequency (HF) bands spectral power, and the short-term scaling indices (α1 and αsign1). The AVS group showed higher values of LF, LF/HF and αsign1 compared with the NAV group at supine position. These patients also expressed smaller changes in meanNN, LF, HF, LF/HF, α1, and αsign1 between positions. In conclusion, we confirmed from short-term recordings that patients with moderate and severe calcific AVS have a decreased cardiac parasympathetic supine response and that the dynamic of heart rate fluctuations is modified compared to NAV subjects, but we also evidenced that they manifest reduced autonomic adjustments caused by the active standing challenge.
Thèses sur le sujet "Aortic valve stenosis (AVS)"
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Ma, Qixiang. « Deep learning based segmentation and detection of aorta structures in CT images involving fully and weakly supervised learning ». Electronic Thesis or Diss., Université de Rennes (2023-....), 2024. http://www.theses.fr/2024URENS029.
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La réparation endovasculaire des anévrismes aortiques abdominaux (EVAR) et l’implantation valvulaire aortique transcathéter (TAVI) sont des interventions endovasculaires pour lesquelles l’analyse des images CT préopératoires est une étape préalable au planning et au guidage de navigation. Dans le cas de la procédure EVAR, les travaux se concentrent spécifiquement sur la question difficile de la segmentation de l’aorte dans l’imagerie CT acquise sans produit de contraste (NCCT), non encore résolue. Dans le cas de la procédure TAVI, ils abordent la détection des repères anatomiques permettant de prédire le risque de complications et de choisir la bioprothèse. Pour relever ces défis, nous proposons des méthodes automatiques basées sur l’apprentissage profond (DL). Un modèle entièrement supervisé basé sur la fusion de caractéristiques 2D-3D est d’abord proposé pour la segmentation vasculaire dans les NCCT. Un cadre faiblement supervisé basé sur des pseudo-labels gaussiens est ensuite envisagé pour réduire et faciliter l’annotation manuelle dans la phase d’apprentissage. Des méthodes hybrides faiblement et entièrement supervisées sont finalement proposées pour étendre la segmentation à des structures vasculaires plus complexes, au-delà de l’aorte abdominale. Pour la valve aortique dans les CT cardiaques, une méthode DL de détection en deux étapes des points de repère d’intérêt et entièrement supervisée est proposée. Les résultats obtenus contribuent à l’augmentation de l’image préopératoire et du modèle numérique du patient pour les interventions endovasculaires assistées par ordinateurEndovascular aneurysm repair (EVAR) and transcatheter aortic valve implantation (TAVI) are endovascular interventions where preoperative CT image analysis is a prerequisite for planning and navigation guidance. In the case of EVAR procedures, the focus is specifically on the challenging issue of aortic segmentation in non-contrast-enhanced CT (NCCT) imaging, which remains unresolved. For TAVI procedures, attention is directed toward detecting anatomical landmarks to predict the risk of complications and select the bioprosthesis. To address these challenges, we propose automatic methods based on deep learning (DL). Firstly, a fully-supervised model based on 2D-3D features fusion is proposed for vascular segmentation in NCCTs. Subsequently, a weakly-supervised framework based on Gaussian pseudo labels is considered to reduce and facilitate manual annotation during the training phase. Finally, hybrid weakly- and fully-supervised methods are proposed to extend segmentation to more complex vascular structures beyond the abdominal aorta. When it comes to aortic valve in cardiac CT scans, a two-stage fully-supervised DL method is proposed for landmarks detection. The results contribute to enhancing preoperative imaging and the patient's digital model for computer-assisted endovascular interventions
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Lopez, Marco Ana. « Low-flow low-gradient aortic stenosis : outcomes after aortic valve replacement ». Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/667817.
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Aortic stenosis is the commonest valve disorder in the Western World. The natural history of the disease is very well described; with a decreased survival once symptoms occur. There is currently, no medical therapy available to reduce the natural progression of the aortic stenosis, and therefore, aortic valve replacement has been recognised as the standard of care treatment for symptomatic aortic stenosis, with TAVI having merged as alternative for those cases with high/prohibitive surgical risk.
All types of aortic stenosis have in common a reduced valve area (AVA <1.0cm2), but depending on the mean gradients and the stroke volume index, there are different types: Normal-Flow High-Gradient (NFHG AS) and Low-Flow Low-Gradient (LFLG AS) aortic stenosis. The latter is further subdivided into Classical and Paradoxical forms depending on the ejection fraction value.
NFHG AS is the most common type. The left ventricle is capable of generating a normal flow through the stenotic valve, that it is translated onto high gradients. This type has been thoroughly studied and has an excellent prognostic with aortic valve replacement, with very low in-hospital mortality and long-term survival similar to the age-matched population.
LFLG AS, on the other hand, is defined by a reduced stroke volume (SVi < 35 ml/min) and a low gradient (mean gradient < 40mmHg).
The Classical form (CLFLG AS) has impaired ventricular function. These patients have dilated ventricles that are not able to generate enough flow through the stenotic valve and hence the low gradient. Dobutamine stress echocardiography is key for the diagnosis of this subtype, as it differentiates it from the Pseudo-Severe aortic stenosis (in which the problem is not in the aortic valve but in the left ventricle, and therefore there is no benefit from aortic valve replacement) and it has also prognostic value by determining the contractile reserve.
These patients have been reported to have the highest mortality post aortic valve replacement and a reduced long-term survival; however, those who survive achieve excellent functional class.
The other subtype of LFLG, the Paradoxical form (PLFLG AS) has a preserved ventricular function. These patients have a ventricular restrictive physiology, with reduced SVi due to a combination of mechanism such as subendocardial fibrosis, concentric remodeling, impaired diastolic filling and high afterload.
It is paramount here to confirm the diagnosis by accurate echocardiography, ruling out measurement errors and other causes of reduced SVi. PLFLG AS patients have worse prognosis than NFHG AS but better prognosis than CLFLG AS patients.
The primary hypothesis of our research project was that aortic valve replacement could be performed in patients with LFLG AS with low in-hospital mortality. Therefore, with the objectives of determining operative and mid-term outcomes of surgical intervention in LFLG AS compared to NFHG AS, we conducted a retrospective analysis of all patients who underwent isolated aortic valve replacement in our centre. Primary end-points were mortality (in-hospital, at one and five years) and the secondary end-points analysed were postoperative complications and clinical status at follow-up.
Patients in the LFLG AS group were significantly older and had more cardiovascular risk factors and comorbidities than the NFHG AS group. Despite those differences, in-hospital mortality was equivalent and remarkably low in both groups. As expected, LFLG AS patients had a reduced mid-term survival but those who survived remained in an excellent functional class.
With the separate analysis of the LFLG AS subgroups, we confirmed that CLFLG AS had higher in-hospital and mid-term mortality than PLFLG AS patients. In both groups, the in-hospital mortality was remarkably low compared to previous literature reports. Aortic valve replacement provided symptomatic relief and excellent functional class during the mid-term follow-up as well as recovery of the ventricular function in most of the patients.
Based on our results, we concluded that aortic valve replacement should be recommended for symptomatic severe LFLG AS.La estenosis aórtica es la enfermedad valvular más frecuente en el tercer mundo. La historia natural de la enfermedad es bien conocida desde hace décadas, siendo una enfermedad con mal pronóstico a medio-corto plazo que hace necesario someter a estos pacientes a recambio valvular aórtico tras la aparición de síntomas. La forma mas común de estenosis aórtica, con flujo normal y gradiente alto, tiene un pronóstico excelente tras el recambio valvular aórtico, con una supervivencia similar a la de la población normal. Sin embargo, la estenosis aórtica de bajo-flujo y bajo-gradiente, es una entidad menos conocida y de peor pronóstico. Estos pacientes tienen una mortalidad mucho mayor tras recambio valvular aórtico y menor supervivencia a largo plazo. El diagnóstico en el bajo-flujo bajo-gradiente es vital para seleccionar correctamente los pacientes con estenosis aórtica que se beneficiarán de tratamiento quirúrgico, teniendo también valor pronóstico, dependiendo de la categoría de bajo flujo (Clásica o Paradójica) y otros determinantes como la presencia/ausencia de reserva contráctil del ventrículo izquierdo. Nuestra hipótesis fue que la estenosis aórtica de bajo-flujo y bajo-gradiente, pueden ser tratada con recambio valvular aórtico con una mortalidad hospitalaria similar a aquellos con flujo normal y alto gradiente. Los objetivos del proyecto fueron el análisis de resultados hospitalarios y a medio plazo (mortalidad hospitalaria, a 1 y 5 años) así como la clase funcional y recuperación de la función ventricular, en pacientes con estenosis aórtica de bajo-flujo bajo-gradiente sometidos a recambio valvular aórtico comparado con flujo normal alto-gradiente. Nuestros resultados nos llevan a la conclusión de que el recambio valvular aórtico en pacientes con estenosis aórtica de bajo-flujo bajo-gradiente se puede lograr con baja mortalidad quirúrgica, comparable con pacientes con flujo normal y alto gradiente. A pesar de que tener una mayor mortalidad a medio-plazo, los supervivientes exhiben una excelente clase funcional y desaparición de síntomas, que apoyan la indicación quirúrgica en estos pacientes.
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Paul, Anup K. « Assessment of the Severity of Aortic Stenosis using Aortic Valve Coefficient ». University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1470672658.
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Rubino, A. S. (Antonino S. ). « Efficacy of the Perceval sutureless aortic valve bioprosthesis in the treatment of aortic valve stenosis ». Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526212289.
Texte intégralRésumé :
Abstract Aortic valve stenosis (AS) is one of the most diffuse valvular diseases in developed countries. AS is a progressive disease, which usually results in serious life-threatening adverse events. Defining a treatment strategy for AS is a focus of cardiovascular research, although the topic is still controversial because of its related clinical and economical implications. Surgical aortic valve replacement (AVR),which is regarded as the gold standard for the treatment of severe symptomatic AS, affords excellent results, particularly in asymptomatic patients with good functional status. AVR requires the institution of cardiopulmonary bypass and aortic cross-clamping, and the duration of these procedures is directly associated with increasing morbidity and mortality, especially in patients with preoperative comorbidities. Accordingly, techniques aimed at decreasing the duration of cardiopulmonary bypass and aortic cross-clamping have the potential to improve postoperative outcomes of AVR. In the present study, we demonstrated that the Perceval sutureless bioprosthesis could significantly reduce the duration of the surgical procedure. This was associated with improved immediate postoperative outcomes and long-term freedom from adverse events. The use of a Perceval sutureless bioprosthesis can facilitate AVR through minimally invasive approaches and is associated with fewer transfusions of packed red cells compared to full sternotomy approaches, even with traditional stented bioprostheses. It could be expected that patients at intermediate-high risk would benefit more from the combination of a fast surgical procedure, performed with reduced surgical invasiveness. When compared to transcatheter aortic valve implantation (TAVI), the Perceval sutureless bioprosthesis was associated with increased incidence of device success as well as less paravalvular leak, with similar immediate and 1-year outcomes. Finally, AVR with the Perceval sutureless bioprosthesis provided excellent hemodynamics at rest and under high workload. The significant increase of effective orifice area under stress suggests that the Perceval sutureless bioprosthesis is the valve of choice for patients with small aortic annuli or when prosthesis-patient mismatch is anticipatedTiivistelmä Aorttaläpän ahtauma on yksi yleisimmistä läppävioista kehittyneissä maissa. Aorttaläpän ahtauma on etenevä sairaus, joka yleensä johtaa vakaviin henkeä uhkaaviin haittatapahtumiin. Aorttaläpän ahtauman hoitotavasta keskustellaan kiivaasti sydän- ja verisuonitautien tutkimuksessa siihen liittyvien kliinisten ja taloudellisten vaikutusten vuoksi. Aorttaläppäleikkausta, jossa aorttaläppä korvataan proteesilla, on aina pidetty vaikean oireisen aorttaläpän ahtauman hoidon kultaisena standardina, koska sen tulokset ovat erinomaisia, etenkin oireettomilla potilailla, joilla sydämen toiminta on hyvä. Leikkaus vaatii sydän-keuhkokoneen käyttöä ja aortan sulkemista, joiden kesto on suoraan yhteydessä kasvavaan sairastavuuteen ja kuolleisuuteen erityisesti potilailla, joilla on muitakin sairauksia. Niinpä tekniikat, jotka lyhentävät sydän-keuhkokoneen käyttöaikaa ja aortan sulkuaikaa, voivat mahdollisesti parantaa aorttaläppäleikkauksen tuloksia. Tässä tutkimuksessa osoitettiin, että ompeleettoman biologisen Perceval-läppäproteesin käyttö vähensi merkittävästi leikkauksen kestoa. Tämä oli yhteydessä parantuneisiin lyhyen ja pitkän aikavälin tuloksiin leikkauksen jälkeen. Ompeleettoman biologisen Perceval-läppäproteesin käyttö voi helpottaa aorttaläppäleikkausta, koska se voidaan asentaa vähemmän kajoavasta avauksesta, ja siihen liittyy vähemmän punasolusiirtoja rintalastan kokoavaukseen verrattuna, myös silloin kun käytetään kokoavausta ja perinteisiä stenttibioproteeseja. Voisi olla odotettavaa, että keskisuuren tai suuren riskin potilaat hyötyisivät enemmän leikkauksesta, jossa yhdistyvät toimenpiteen nopeus ja vähäisempi kajoavuus. Katetriteitse asennettuun biologiseen keinoläppään (TAVI) verrattuna ompeleeton biologinen Perceval-läppäproteesi oli yhteydessä parempaan laitteen toimimiseen ja pienempään paravalvulaariseen vuotoon. Muut tulokset heti leikkauksen jälkeen ja yhden vuoden seurannassa olivat samanlaisia. Lopuksi voidaan todeta, että aorttaläppäleikkaukseen ompeleettomalla biologisella Perceval-läppäproteesilla liittyi erinomainen hemodynamiikka levossa ja korkean työkuorman aikana. Stressin aikaisen tehokkaan aorttaläpän aukon pinta-alan merkittävä kasvu osoittaa, että ompeleeton biologinen Perceval-läppäproteesi on hyvä valinta potilaille, joilla on pieni aorttaläpän aukko tai kun on odotettavissa proteesin ja potilaan yhteensopimattomuutta
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Peltonen, T. (Tuomas). « Endothelial factors in the pathogenesis of aortic valve stenosis ». Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514289880.
Texte intégralRésumé :
Abstract
Calcified aortic valve disease represents a spectrum of disease spanning from mild aortic valve sclerosis to severe aortic valve stenosis (AS), being an actively regulated disease process and
showing some hallmarks of atherosclerosis. The calcified aortic valve lesion develops endothelial injury and is characterized by inflammation, lipid accumulation, renin-angiotensin system activation
and fibrosis. There is no approved pharmacological treatment available in AS.
This study was aimed to characterize gene expression of endothelial factors in aortic valves in patients representing different stages of calcified aortic valve disease to reveal new targets for
pharmacological interventions in AS. Aortic valves obtained from 75 patients undergoing valve replacement surgery were studied. Expression of natriuretic peptides (ANP, BNP and CNP), their processing
enzymes (corin and furin), natriuretic receptors (NPR-A, NPR-B and NPR-C), endothelin-1 (ET-1), endothelin converting enzyme-1 (ECE-1), endothelin receptors A and B (ETA and
ETB), and apelin pathway (apelin and its receptor APJ) was characterized by reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry.
AS was characterized by distinct downregulation of gene expression of CNP, its processing enzyme furin and the target receptor NPR-B. Furthermore, increased amount of ET-1 and its target
receptor ETA as well as imbalance between ETA and ETB receptors and downregulated endothelial nitric oxide synthase (eNOS) gene
expression were observed. Finally, gene expression of apelin and APJ receptor were significantly upregulated in stenotic valves when compared to controls in combination with disequilibrium between
expression of angiotensin II receptors AT1 and AT2. The study provides a better understanding of molecular mechanisms associated with calcific aortic
valve disease and suggest potential targets for novel therapeutic interventions.
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MOSCHETTA, DONATO. « UNRAVELLING SEX-DEPENDENT MECHANISMS IN CALCIFIC AORTIC VALVE STENOSIS ». Doctoral thesis, Università degli Studi di Milano, 2022. https://hdl.handle.net/2434/947275.
Texte intégralRésumé :
Calcific aortic valve stenosis (CAVS) is the most common form of heart valve disease and affects about 3% of the population. Its prevalence increases with age, without a causal relation between ageing and CAVS development. To date, CAVS is a slow, progressive, multifactorial disorder considered to be actively driven by several cellular and molecular processes. Its natural history consists of a long clinically silent phase of non-uniform leaflet thickening with or without minimal calcification, known as aortic valve sclerosis (AVSc), without significant obstruction of blood flow, followed by the symptomatic stage, the aortic valve stenosis (AS). Currently, there is no pharmacological therapy preventing CAVS progression nor treating patients with AS. As a result, surgical or percutaneous aortic valve replacement remain the only treatments for severe AS, leaving the pathological molecular and cellular mechanisms unsolved.
One of the first trigger of the pathology due to the oxidative stress is the endothelial dysfunction, followed by local inflammation and interstitial cells (VIC) differentiation into myofibroblasts and osteoblasts.
Activated valve endothelial cells, undergoing endothelial to mesenchymal transition (EndMT), begin to express mesenchymal adhesion molecules and facilitate monocytes infiltration and local inflammation. These environmental changes induce VIC trans-differentiation into myofibroblast- and osteoblast-like cells. Activated VICs carry out a progressive extracellular matrix (ECM) pathological rearrangement characterized by the activation of fibrosis and calcification processes, which ultimately drive to fibro-calcific deposit formation.
In the last years different studies reported sex-related difference in molecular mechanisms in the context of CAVS. In particular, it was shown that men with AS show a higher aortic valve calcium (AVC) load than women. Recently, it has been described that woman aortic valve leaflets were more fibrotic than man ones. Hence, it has been hypothesized that the mechanisms underlying CAVS progression could be different between the two sexes.
We confirmed the evidence on sex-related calcium load in a meta-analysis performed on almost three thousand AS patients. Based on our results, AVC load, evaluated by computed tomography, is higher in man AS patients than in woman ones, even normalizing the data for the state of the pathology and for the aortic
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annulus area. By the CT scan images analysis, we confirmed also the higher prevalence of fibrotic tissue in woman AS patients, than in men.
In silico analysis of whole tissue RNA microarray revealed that the cellular composition of the aortic valve was different between men and women with CAVS. In particular, women showed a prevalence of mesenchymal cells, while in men there was a prevalence of inflammatory cells. This finding was in line with the analysis of circulating cytokines: pro inflammatory cytochines such as IL1β, TNFα, INFβ, and INFγ were upregulated in men CAVS patients.
Based on these premises, we isolated and characterized VICs from AS patients and performed RNA sequencing to evaluate the differentially expressed molecular mechanisms. Among pathways overactivated in men there was the mitochondrial gene expression and this finding was confirmed by the higher mitochondrial damage in AS VICs from men respect to the one from women. We hypothesized that the mitochondrial damage caused a lower ATP production, therefore we evaluated the effects of a synthetic ATP equivalent, the 2ThioUTP, on the extracellular calcification of VICs from CAVS men. The in vitro 2ThioUTP administration showed indeed lower extracellular calcification of CAVS VICs both in normal and pro-calcifying conditions.
All these data, taken together with robust literature evidences, shed light on the influence of sex in the development and progression of CAVS disease. Further studies are needed to better define the sexual dimorphism of this detrimental pathology. The recognition of sex-specific molecular mechanisms, linked to AS onset, may help in the identification of a gender-specific targeted therapy. In this direction, novel pharmacological therapies intended to reduce or even halt CAVS progression could be discovered, providing the basis for a personalized medicine approach in the context of CAVS.
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Pawade, Tania Ashwinikumar. « Imaging calcification in aortic stenosis ». Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/29589.
Texte intégralRésumé :
BACKGROUND Aortic stenosis is a common and potentially fatal condition in which fibro-calcific changes within the valve leaflets lead to the obstruction of blood flow. Severe symptomatic stenosis is an indication for aortic valve replacement and timely referral is essential to prevent adverse clinical events. Calcification is believed to represent the central process driving disease progression. 18F-Fluoride positron emission tomography computed tomography (PET-CT) and CT aortic valve calcium scoring (CT-AVC) quantify calcification activity and burden respectively. The overarching aim of this thesis was to evaluate the applications of these techniques to the study and management of aortic stenosis. METHODS AND RESULTS REPRODUCIBILITY The scan-rescan reproducibility of 18F-fluoride PET-CT and CT-AVC were investigated in 15 patients with mild, moderate and severe aortic stenosis who underwent repeated 18F-fluoride PET-CT scans 3.9±3.3 weeks apart. Modified techniques enhanced image quality and facilitated clear localization of calcification activity. Percentage error was reduced from ±63% to ±10% (tissue-to-background ratio most-diseased segment (MDS) mean of 1.55, bias -0.05, limits of agreement - 0·20 to +0·11). Excellent scan-rescan reproducibility was also observed for CT-AVC scoring (mean of differences 2% [limits of agreement, 16 to -12%]). AORTIC VALVE CALCIUM SCORE: SINGLE CENTRE STUDY Sex-specific CT-AVC thresholds (2065 in men and 1271 in women) have been proposed as a flow-independent technique for diagnosing severe aortic stenosis. In a prospective cohort study, the impact of CT-AVC scores upon echocardiographic measures of severity, disease progression and aortic valve replacement (AVR)/death were examined. Volunteers (20 controls, 20 with aortic sclerosis, 25 with mild, 33 with moderate and 23 with severe aortic stenosis) underwent CT-AVC and echocardiography at baseline and again at either 1 or 2-year time-points. Women required less calcification than men for the same degree of stenosis (p < 0.001). Baseline CT-AVC measurements appeared to provide the best prediction of subsequent disease progression. After adjustment for age, sex, peak aortic jet velocity (Vmax) ≥ 4m/s and aortic valve area (AVA) < 1 cm2, the published CT-AVC thresholds were the only independent predictor of AVR/death (hazard ratio = 6.39, 95% confidence intervals, 2.90-14.05, p < 0.001). AORTIC VALVE CALCIUM SCORE: MULTICENTRE STUDY CT-AVC thresholds were next examined in an international multicenter registry incorporating a wide range of patient populations, scanner vendors and analysis platforms. Eight centres contributed data from 918 patients (age 77±10, 60% male, Vmax 3.88±0.90 m/s) who had undergone ECG-gated CT within 3 months of echocardiography. Of these 708 (77%) had concordant echocardiographic assessments, in whom our own optimum sex-specific CT-AVC thresholds (women 1377, men 2062 AU) were nearly identical to those previously published. These thresholds provided excellent discrimination for severe stenosis (c-statistic: women 0.92, men 0.88) and independently predicted AVR and death after adjustment for age, sex, Vmax ≥4 m/s and AVA < 1 cm2 (hazards ratio, 3.02 [95% confidence intervals, 1.83-4.99], p < 0.001). In patients with discordant echocardiographic assessments (n=210), CT-AVC thresholds predicted an adverse prognosis. BICUSPID AORTIC VALVES Within the multicentre study, higher continuity-derived estimates of aortic valve area were observed in patients with bicuspid valves (n=68, 1.07±0.35 cm) compared to those with tri-leaflet valves (0.89±0.36 cm p < 0.001,). This was despite no differences in measurements of Vmax (p=0.152), or CT-AVC scores (p=0.313). The accuracy of AVA measurments in bicuspid valves was therefore tested against alternative markers of disease severity. AVA measurements in bicuspid valves demonstrated extremely weak associations with CT-AVC scores (r2=0.08, p=0.02) and failed to correlate with downstream markers of disease severity in the valve and myocardium and against clinical outcomes. AVA measurements in bicuspid patients also failed to independently predict AVR/death after adjustment for Vmax ≥4 m/s, age and gender. In this population CT-AVC thresholds (women 1377, men 2062 AU) again provided excellent discrimination for severe stenosis. CONCLUSIONS Optimised 18F-fluoride PET-CT scans quantify and localise calcification activity, consolidating its potential as a biomarker or end-point in clinical trials of novel therapies. CT calcium scoring of aortic valves is a reproducible technique, which provides diagnostic clarity in addition to powerful prediction of disease progression and adverse clinical events.
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Zhao, Ying. « Effect of valve replacement for aortic stenosis on ventricular function ». Doctoral thesis, Umeå universitet, Institutionen för folkhälsa och klinisk medicin, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-46809.
Texte intégralRésumé :
Background：Aortic stenosis (AS) is the commonest valve disease in the West. Aortic valve replacement (AVR) remains the only available management for AS and results in improved symptoms and recovery of ventricular functions. In addition, it is well known that AVR results in disruption of LV function mainly in the form of reversal of septal motion as well as depression of right ventricular (RV) systolic function. The aim of this thesis was to study, in detail, the early and mid-term response of ventricular function to AVR procedures (surgical and TAVI) as well as post operative patients’ exercise capacity. Methods：We studied LV and RV function by Doppler echocardiography and speckle tracking echocardiography (STE) in the following 4 groups; (1) 30 severe AS patients (age 62±11 years, 19 male) with normal LV ejection fraction (EF) who underwent AVR, (2) 20 severe AS patients (age 79±6 years, 14 male) who underwent TAVI, (3) 30 healthy controls (age 63±11 years, 16 male), (4) 21 healthy controls (age 57±9 years, 14 male) who underwent exercise echocardiography. Results: After one week of TAVI, the septal radial motion and RV tricuspid annulus peak systolic excursion (TAPSE) were not different from before, while surgical AVR had significantly reversed septal radial motion and TAPSE dropped by 70% compared to before. The extent of the reversed septal motion correlated with that of TAPSE (r=0.78, p<0.001) in the patients as a whole after AVR and TAVI (Study I). Compared with controls, the LV twist function was increased in AS patients before and normalized after 6 months of surgical AVR. In controls, the LV twist correlated with LV fractional shortening (r=0.81, p<0.001), a relationship which became weak in patients before (r=0.52, p<0.01) and after AVR (r=0.34, p=ns) (Study II). After 6 months of surgical AVR, the reversed septal radial motion was still significantly lower than before. The septal peak displacement also decreased and its time became prolonged. In contrast, the LV lateral wall peak displacement increased and the time to peak displacement was early. The accentuated lateral wall peak displacement correlated with the septal peak displacement time delay (r=0.60, p<0.001) and septal-lateral time delay (r=0.64, p<0.001) (Study III). In 21 surgical AVR patients who performed exercise echocardiography, the LV function was normal at rest but different from controls with exercise. At peak exercise, oxygen consumption (pVO2) was lower in patients than controls. Although patients could achieve cardiac output (CO) and heart rate (HR) similar to controls at peak exercise, the LV systolic and early diastolic myocardial velocities and strain rate as well as their delta changes were significantly lower than controls. pVO2 correlated with peak exercise LV myocardial function in the patients group only, and the systolic global longitudinal strain rate (GLSRs) at peak exercise was the only independent predictor of pVO2 in multivariate regression analysis (p=0.03) (Study IV). Conclusion: Surgical AVR is an effective treatment for AS patients, but results in reversed septal radial motion and reduced TAPSE. The newly developed TAVI procedure maintains RV function which results in preservation of septal radial motion. In AS, the LV twist function is exaggerated, normalizes after AVR but loses its relationship with basal LV function. While the reversed septal motion results in decreased and delayed septal longitudinal displacement which is compensated for by the accentuated lateral wall displacement and the time early. These patients remain suffering from limited exercise capacity years after AVR.
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Bagur, Rodrigo Hernan. « Transcatheter aortic valve implantation for the treatment of patients with severe symptomatic aortic stenosis ». Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/29420/29420.pdf.
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Fairbairn, Tim. « Severe aortic valve stenosis and the consequences of transcatheter and surgical aortic valve replacement : a cardiovascular magnetic resonance study ». Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5853/.
Texte intégralRésumé :
Background: Severe symptomatic aortic stenosis (AS) heralds a poor prognostic outlook and significant co-morbidity, with valve replacement the only definitive cure. Transcatheter aortic valve implantation (TAVI) has developed as an alternative to the standard treatment of surgical aortic valve replacement (SAVR) in high-risk or inoperable AS patients. The clinical and cost effectiveness of TAVI compared to SAVR requires further investigation. Methods: A prospective study of sixty seven TAVI and twenty seven SAVR patients, recruited from September 2009 to September 2011. Baseline assessments included a cerebral and cardiovascular magnetic resonance scan (1.5 Tesla MRI system) and the completion of two health surveys (EQ 5D and SF 12). Follow-up MRI was performed at 5±2 days (cerebral MRI) and 6 months (cardiovascular MRI) post AVR. Health status was assessed at 30 days, 6 months and one year. A cost-effectiveness analysis was performed using a 10 year Markov model with deterministic and probabilistic sensitivity analyses. Results: TAVI and SAVR resulted in similar levels of ventricular reverse remodelling. TAVI had a greater reduction in valvular impedance (21±8mmHg vs. 35±13mmHg, p=0.017) and myocardial fibrosis (10.9±6 % vs. 8.5±5%, p=0.03). Cerebral emboli occurred in 77% of TAVI patients. Age (r=0.37, p=0.042), severity of atheroma (r=0.91, p<0.001) and catheterisation time (r=0.45, p=0.02) were predictors of cerebral infarcts. HRQOL significantly improved over 12 months (PCS, p=0.02; EQ-5D, p=0.02; VAS, p=0.01 and SF6D p=0.03). Male gender (SF6D, p=0.01) and increased operator experience (PCS, EQ5D and VAS, p<0.05) predicted an improvement in HRQOL. Despite greater procedural costs, TAVI was cost-effective compared to SAVR over the 10 year model horizon (costs £52,593 vs. £53,943 and QALYs 2.81 vs. 2.75) indicating that TAVI dominated SAVR. Conclusions: TAVI has comparable cardiac and health benefits to SAVR, but greater cerebral complications. TAVI is likely to represent a clinical and cost effective alternative to SAVR.
Livres sur le sujet "Aortic valve stenosis (AVS)"
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Huber, Christoph. Transcatheter valve therapies. New York : Informa Healthcare USA, 2009.
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M, Bashore Thomas, et Davidson Charles J, dir. Percutaneous balloon valvuloplasty and related techniques. Baltimore : Williams & Wilkins, 1991.
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Baumgartner, Helmut, Stefan Orwat, Elif Sade et Javier Bermejo. Heart valve disease (aortic valve disease) : aortic stenosis. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198726012.003.0032.
Texte intégralRésumé :
Echocardiography has become the gold standard for the assessment of patients with aortic stenosis (AS). It allows morphological assessment of the aortic valve and provides information on the aetiology of the disease. The quantification of AS includes primarily the measurement of transaortic jet velocities and gradients as well as the calculation of the valve area, thus combining flow-dependent and relatively flow-independent variables. Awareness of potential pitfalls is fundamental when assessing these variables. Haemodynamic consequences of AS on left ventricular (LV) size, wall thickness, and function as well as associated valve lesions and estimates of pulmonary artery pressure are required for the comprehensive evaluation of the disease. In the setting of classical low-flow–low-gradient AS with reduced LV systolic function, low-dose dobutamine echocardiography is of particular diagnostic and prognostic importance. The entity of severe low-flow–low-gradient AS in the presence of preserved LV function remains a particular diagnostic challenge. For accurate differentiation from pseudo-severe AS or misclassified moderate AS, an integrated approach including additional variables such as the extent of valve calcification by computed tomography may be required. In addition to the assessment of AS aetiology and quantification of its severity, echocardiography can provide predictors of outcome that may have a major impact on the decision for intervention.
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Rosenhek, Raphael, Robert Feneck et Fabio Guarracino. Aortic valve disease. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199599639.003.0014.
Texte intégralRésumé :
Echocardiography is the gold standard for the assessment of patients with aortic valve (AoV) disease. It allows a detailed morphological assessment of the AoV and thereby makes determination of the aetiology possible. In general, the quantification of aortic stenosis is based on the measurement of transaortic jet velocities and the calculation of AoV area, thus combining a flow-dependent and a flow-independent variable. In the setting of low-flow low-gradient AS, dobutamine echocardiography is of particular diagnostic and prognostic importance. The quantification of aortic regurgitation is based on qualitative and quantitative parameters. Awareness of potential pitfalls is fundamental. Haemodynamic consequences of AoV disease on left ventricular size, hypertrophy, and function as well as potentially coexisting valve lesions can be assessed simultaneously. In patients with AoV disease, predictors of outcome and indications for surgery are substantially defined by echocardiography.
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Thorne, Sara, et Sarah Bowater. Valve and outflow tract lesions. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198759959.003.0008.
Texte intégralRésumé :
This chapter discusses valve and outflow tract lesions. It considers left ventricular outflow tract obstruction (LVOTO), including subvalvar aortic stenosis (AS), bicuspid aortic valve, and supravalvar AS. Also discussed are left ventricular inflow lesions, including congenital mitral valve abnormalities, cor triatriatum, and Shone syndrome. It also covers right ventricular outflow tract obstruction (RVOTO), including pulmonary valvar stenosis, supravalvar pulmonary stenosis, pulmonary artery stenosis, pulmonary atresia with intact septum, and double-chambered right ventricle. Ebstein anomaly is also discussed, including incidence, associations, natural history, presenting features in the adult, investigations, and management.
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Thorne, Sara, et Paul Clift, dir. Left ventricular outflow tract obstruction (LVOTO). Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199228188.003.0008.
Texte intégralRésumé :
Introduction 68Subvalvar aortic stenosis (AS) 70Bicuspid aortic valve 72Supravalvar AS 74LVOTO may occur at different levels: • Subvalvular.• Valvular—including bicuspid aortic valve.• Supravalvular.• Coarctation— see p.118.Effects of LVOTO, irrespective of site of lesion, are: • ↑ afterload on LV....
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Lancellotti, Patrizio, Julien Magne, Kim O’Connor et Luc A. Pierard. Mitral valve disease. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199599639.003.0015.
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Native mitral valve disease is the second valvular heart disease after aortic valve disease. For the last few decades, two-dimensional Doppler echocardiography was the cornerstone technique for evaluating patients with mitral valve disease. Besides aetiological information, echocardiography allows the description of valve anatomy, the assessment of disease severity, and the description of the associated lesions.This chapter will address the echocardiographic evaluation of mitral regurgitation (MR) and mitral stenosis (MS).In MR, the following findings should be assessed: 1. Aetiology. 2. Type and extent of anatomical lesions and mechanisms of regurgitation. 3. The possibility of mitral valve repair. 4. Quantification of MR severity. 5. Quantification of MR repercussions.In MS, the following findings should be assessed: 1. Aetiology. 2. Type and extent of anatomical lesions. 3. Quantification of MS severity. 4. Quantification of MS repercussions. 5. Wilkins or Cormier scores for the possibility of percutaneous mitral commissuroplasty.Management of patients with mitral valve disease is currently based on symptoms and on echocardiographic evaluation at rest. Therefore, knowing how to assess the severity of valve diseases as well as the pitfalls and the limitations of each echocardiographic method is of primary importance.
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Lancellotti, Patrizio, et Bernard Cosyns. Adult Congenital Heart Disease. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780198713623.003.0013.
Texte intégralRésumé :
Echocardiography has a fundamental role in patients with adult congenital heart disease. This chapter identifies the role of echocardiography in atrial septal defects, ventricular septal defects, atrioventricular septal defects, patent ductus arteriosus, and persistent left superior vena cava. For each condition, the role of transthoracic and transoesophagael echocardiogram are shown alongside examples of main types and features and haemodynamic effect. Echocardiographic findings of LV outflow tract obstruction, supravalvular aortic stenosis, aortic stenosis, and aortic coarction are covered, as well as an examination of complex congenital lesions, including the tetralogy of Fallot and Ebstein’s anomaly of the tricuspid valve.
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Katritsis, Demosthenes G., Bernard J. Gersh et A. John Camm. Aortic stenosis. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199685288.003.0325_update_004.
Texte intégralRésumé :
Diagnosis and risk stratification of patients with aortic stenosis are presented. Indications for surgical therapy and percutaneous valve implantation based on the recommendations of ACC/AHA and ESC are summarized and tabulated.
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Davey, Patrick, et Jim Newton. Aortic stenosis. Sous la direction de Patrick Davey et David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0093.
Texte intégralRésumé :
Aortic stenosis is characterized by thickening and reduced mobility of the aortic valve leaflets and results in restriction to the blood flow from the left ventricle to the aorta, and secondary left ventricular hypertrophy.
Chapitres de livres sur le sujet "Aortic valve stenosis (AVS)"
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Clavel, Marie-Annick, Nancy Côté et Philippe Pibarot. « Aortic Stenosis ». Dans Heart Valve Disease, 21–46. Cham : Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-23104-0_3.
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Hanzel, George S. « Transcatheter Aortic Valve Replacement ». Dans Aortic Stenosis, 253–69. London : Springer London, 2015. http://dx.doi.org/10.1007/978-1-4471-5242-2_15.
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Sridharan, Shankar, Gemma Price, Oliver Tann, Marina Hughes, Vivek Muthurangu et Andrew M. Taylor. « Aortic Valve Stenosis ». Dans Cardiovascular MRI in Congenital Heart Disease, 36–39. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-69837-1_17.
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Kleman, Mandi E. « Aortic Valve Stenosis ». Dans Veterinary Image-Guided Interventions, 588–94. Oxford : John Wiley & Sons, Ltd, 2015. http://dx.doi.org/10.1002/9781118910924.ch60.
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Schneider, Jordan, et Ronald A. Bronicki. « Aortic Valve Stenosis ». Dans Simulation in Cardiovascular Critical Care Medicine, 151–58. Cham : Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-63557-1_14.
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Shannon, Francis L., Marc P. Sakwa et Robert L. Johnson. « Surgical Management of Aortic Valve Stenosis ». Dans Aortic Stenosis, 197–217. London : Springer London, 2015. http://dx.doi.org/10.1007/978-1-4471-5242-2_12.
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Poon, Karl K. C. « Imaging for Transcatheter Aortic Valve Replacement ». Dans Aortic Stenosis, 231–51. London : Springer London, 2015. http://dx.doi.org/10.1007/978-1-4471-5242-2_14.
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Kerner, Nathan. « Echocardiographic Evaluation of Aortic Valve Stenosis ». Dans Aortic Stenosis, 71–90. London : Springer London, 2015. http://dx.doi.org/10.1007/978-1-4471-5242-2_6.
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Alizadehasl, Azin, et Anita Sadeghpour. « Congenital Aortic Valve Stenosis ». Dans Comprehensive Approach to Adult Congenital Heart Disease, 275–79. London : Springer London, 2014. http://dx.doi.org/10.1007/978-1-4471-6383-1_35.
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Jing, Zaiping, Huajuan Mao, Qingsheng Lu, Chao Song et Lei Zhang. « Cardiac Aortic Valve Stenosis ». Dans Endovascular Surgery and Devices, 103–7. Singapore : Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-8270-2_12.
Texte intégralActes de conférences sur le sujet "Aortic valve stenosis (AVS)"
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Gogarty, Michael B., et Lakshmi P. Dasi. « In Vitro Beating Heart Simulator for Minimally Invasive Heart Valve Therapy Research ». Dans ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80743.
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Heart disease is the number one cause of death today with aortic valve stenosis (AVS) being a major contributor to the mortality rate1. Because of the invasive nature of Aortic Valve Resection (AVR), the typical treatment for AVS, between 30–60% of patients affected by severe aortic stenosis cannot be treated surgically, usually due to age and advanced comorbidities. Qualifying individuals must undergo extensive rehabilitation and of those who qualify 4.3% to 25% do not survive the first year following the procedure3,4.
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Graham, Joel D., M. Keith Sharp, Steven C. Koenig, Guruprasad Giridharan, Michael A. Sobieski et Mark S. Slaughter. « Treatment of Severe Aortic Stenosis : Development and Feasibility Testing of an Aortic Valve Bypass Apical Cannula ». Dans ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53257.
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Treatment of aortic stenosis through surgical replacement has been one of the most successful advances in cardiovascular medicine (1), though use in certain patient populations, specifically in the elderly, has been associated with increased mortality rates (2). A growing alternative surgery is Aortic Valve Bypass (AVB). This therapy offers decreased surgical risk because it does not require cardiopulmonary bypass, aortic crossclamping, aortotomy, or cardioplegic cardiac arrest (3). A one-way conduit between the apex of the left ventricle and the descending aorta increases flow by reducing afterload (Fig. 1, LEFT). Systolic blood from the left ventricle is ejected via both the native stenotic aortic valve and the AVB circuit. In this feasibility study, an apical cannula was developed and tested.
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Agarwal, Ramesh K., et Guangyu Bao. « Numerical Study of Flow Through Models of Aortic Valve Stenoses and Assessment of Gorlin Equation ». Dans ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-26132.
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Gorlin equation has been applied in clinical practice for evaluating the aortic valve area (AVA) of vascular and aortic valve stenosis for past sixty years [1]. It was derived using the Bernoulli equation across the stenosis with the assumption that the velocity of the fluid behind the stenosis is much greater than the velocity upstream of the stenosis. Because of this assumption, the calculated stenosed area may have large error if the flow rate across the valve is low or the stenosis is mild [2]. In a recent paper, Okpara and Agarwal [3] proposed a new equation (Agarwal – Okpara equation) which significantly decreases the evaluation error compared to the Gorlin Equation. The purpose of this paper is to modify the Agarwal – Okpara equation to generalize its applicability based on additional data calculated from the commercial CFD software FLUENT as well as the clinical data obtained from the literature. A total of ten cases are computed using CFD to assess the range of validity of the Gorlin equation and the Agarwal – Okpara equation. In addition, eighty clinical data points were obtained from the papers of Minners et al. [4] and Hakii et al. [5] covering a large range of severity of stenosis. The error in AVA computed from Gorlin equation and Agarwal – Okpara equation varied from 7.44 to 82.14% and 0.06 to 27.26% respectively compared to the CFD simulation data, and 41.47 to 83.60% and 8.88 to 33.98% respectively compared to the clinical data; however, AVA calculated using the Agarwal – Okpara – Bao equation presented in this paper gives results within 0.42 to 9.6% error compared to the exact AVA used in FLUENT simulations, and from 4.76 to 24.13% compared to the clinical data. The Agarwal – Okpara – Bao equation agrees with the clinical data for all relevant flow rates and full range of severity of stenosis. Thus, the use of Agarwal – Okpara – Bao equation to evaluate AVA in clinical practice is suggested.
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Zhang, Ruihang, et Yan Zhang. « Pulsatile Flow Characteristics in a Stenotic Aortic Valve Model : An In Vitro Experimental Study ». Dans ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-4978.
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Abstract Aortic stenosis (AS) is one of the most common valvular heart diseases around the globe. The accurate assessment of AS severity is important and strongly associated with accurate interpretation of the hemodynamic parameters across the stenotic valve. In this study, we conducted in vitro fluid dynamic experiments to investigate the pulsatile flow characteristics of a stenotic aortic valve as a function of heart rate. An in vitro cardiovascular flow simulator was used to generate pulsatile flow with a prescribed waveform (40% systolic period and 4L/min cardiac output) under varied heart rates (50 bpm, 75 bpm and 100 bpm). The stenotic valve was constructed by molding silicone into three-leaflet aortic valve geometries wrapping around thin fabrics which increases its stiffness and tensile strength. Two-dimensional phase-locked particle image velocimetry (PIV) was employed to quantify the flow field characteristics of the stenotic valve. Pressure waveforms were recorded to evaluate the severity of the stenosis via the Gorlin and Hakki equations. Results suggest that as the heart rate increases, the peak pressure gradient across the stenotic aortic valve increases significantly under the same cardiac output. Analysis also shows the estimated aortic valve area (AVA) decreases as the heart rate increases under the same cardiac output using Gorlin equation estimation, while the trend is reversed using Hakki equation estimation. Under phase-locked conditions, quantitative flow characteristics, such as phase-averaged flow velocity, turbulence kinetic energy (TKE) for the stenotic aortic valve were analyzed based on the PIV data. Results suggest that the peak systolic jet velocity downstream of the valve increases as the heart rate increases, implying a longer pressure recovery distance as heart rate increases. While the turbulence at peak systole is higher under the slower heart rate, the faster heart rate contributes to a higher turbulence during the late systole and early diastole phases. Based on the comparison with no-valve cases, the differences in TKE was mainly related to the dynamics of leaflets under different heart rates. Overall, the results obtained in this study demonstrate that the hemodynamics of a stenotic aortic valve is complex and the assessment of AS could be significantly affected by the pulsating rate of the flow.
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Barker, A. J., P. van Ooij, K. Bandi, J. Garcia, P. McCarthy, J. Carr, C. Malaisrie et M. Markl. « Viscous Energy Loss in Aortic Valve Disease Patients ». Dans ASME 2013 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/sbc2013-14142.
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Purpose : Aortic valve disease (AVD) in the form of stenosis, insufficiency, or congenital defect will disrupt normal function beyond the valve itself. This includes an increase in cardiac afterload and a drastic alteration in post-valvular 3D blood flow patterns 1, 2. The current AHA/ACC standard-of-care guidelines, however, assess disease severity based on simplified measurements local to the valve, such as: peak velocity, effective orifice area, regurgitation, aortic diameter and transvalvular pressure gradient 3. Paradoxically, it is known that similarly classified AVD patients under these guideline metrics can exhibit radically divergent outcomes — implying an incomplete characterization of the disease 4. For this reason, functional assessment and risk-stratification may benefit from a robust methodology capable of quantifying the energetic load placed on the left ventricle (LV) due to the presence of AVD. The measurement of viscous energy loss, a parameter which is directly responsible for increased cardiac afterload and is independent of pressure recovery effects, is a promising candidate to quantify LV loading. With this in mind, the 4D flow technique (time-resolved 3D phase-contrast MRI with all principal velocity directions encoded) provides the necessary information to calculate this parameter. Therefore, we present a theoretical basis for the use of 4D flow MRI to characterize in-vivo energy loss and apply the technique in a pilot study of patients with aortic valve stenosis (n = 13) or aortic dilation (n = 17) as compared to normal controls (n = 12).
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Fujita, B., K. Bozkurt, M. Saad, E. Emmel, I. Eitel, A. Aboud, H. Langer, S. Ensminger et T. Kurz. « Surgical versus Transcatheter Aortic Valve Replacement for Treatment of Bicuspid Aortic Valve Stenosis ». Dans 49th Annual Meeting of the German Society for Thoracic and Cardiovascular Surgery. Georg Thieme Verlag KG, 2020. http://dx.doi.org/10.1055/s-0040-1705303.
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Kato, Takayoshi, Tomohiro Tsunekawa, Yusuke Motoji, Tatsuomi Kinoshita, Yasuhide Okawa et Shinji Tomita. « 19 Aortic valve replacement for severe aortic stenosis with low ejection fraction ». Dans 1st Asia Pacific Advanced Heart Failure Forum (APAHFF), 15th December 2017, Hong Kong. BMJ Publishing Group Ltd, British Cardiovascular Society and Asia Pacific Heart Association, 2018. http://dx.doi.org/10.1136/heartasia-2018-apahff.19.
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Bonello, Bea, Michelle Carr, Richard Issitt, Marina Hugues, Alessandro Giardini, Xavier Iriart, Victor Tsang, Martin Kostolny, Sachin Khambadkone et Jan Marek. « 86 Long-term outcome of critical aortic valve stenosis ». Dans GOSH Conference 2019, Care of the Complex Child. BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health, 2019. http://dx.doi.org/10.1136/archdischild-2019-gosh.86.
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Tent, Michiel. « Durable benefits of TAVR versus surgical aortic valve replacement in aortic stenosis patients ». Dans ACC 2023 Scientific Session, sous la direction de Marc Bonaca. Baarn, the Netherlands : Medicom Medical Publishers, 2023. http://dx.doi.org/10.55788/08fb868c.
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Heinrich, Russell S., Arnold A. Fontaine, Randall Y. Grimes, Kristin E. Moore, Robert A. Levine et Ajit P. Yoganathan. « Analysis of Fluid Mechanical Energy Losses in Aortic Valve Stenosis ». Dans ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-1180.
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Abstract Aortic valve stenosis occurs when the aortic valve does not open fully during systole, thus creating an obstruction to blood flow leaving the left ventricle. Maximum orifice pressure drop and valve orifice area are the primary clinical indicators of the severity of aortic stenosis. Pressure drop can be measured by catheter insertion or calculated with the modified Bernoulli equation from Doppler ultrasound velocity measurements. Unfortunately there are discrepancies between the two techniques that are often attributed to pressure recovery downstream of stenotic aortic valves [Levine et al, 1989]. The relationship between orifice pressure drop and left ventricular function is ambiguous. This has been emphasized in a recent paper by Vandervoort et al [1996], which states, “Although maximum, transvalvular, and net pressure gradients are all different gradients that physically exist, it is currently not known which of these gradients is most relevant to reflect the work load imposed on the heart”. Since it has been shown that left ventricular function has a significant effect on post-operative recovery [Ross, 1985], it is imperative that the severity of aortic valve stenosis be evaluated in terms of left ventricular work capacity. Therefore, the purpose of this study was to determine the relationship between left ventricular work and pressure drop measurements in aortic stenosis. The hypothesis that motivated this study was that the left ventricle performs work to overcome energy losses caused by aortic valve stenosis, and the pressure drop that most accurately represents this work should be used for clinical assessment of aortic stenosis.
Rapports d'organisations sur le sujet "Aortic valve stenosis (AVS)"
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Shao, Ruochen, et Junli Li. Efficacy and Safety of Emergent Transcatheter Aortic Valve Implantation in Patients with Decompensated Aortic Stenosis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, avril 2021. http://dx.doi.org/10.37766/inplasy2021.4.0050.
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Song, Yumeng, Yutong Wang, Zuoxiang Wang et Tingbo Jiang. Comparing clinical outcomes on oncology patients with severe aortic stenosis undergoing transcatheter aortic valve implantation： A systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, février 2022. http://dx.doi.org/10.37766/inplasy2022.2.0009.
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Genereux, Philippe, et Roxanna seyedin. Transcatheter or surgical aortic valve replacement versus clinical surveillance in asymptomatic severe aortic stenosis : A protocol for a systematic review and meta-analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, septembre 2024. http://dx.doi.org/10.37766/inplasy2024.9.0002.
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Transcatheter aortic valve implantation may be an option for patients with aortic stenosis at lower surgical risk. National Institute for Health Research, septembre 2019. http://dx.doi.org/10.3310/signal-000818.
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