10 results on '"Graup, Vera"'
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2. Production and characterisation of tissue-mimicking collagen scaffolds for cardiac tissue engineering
- Author
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Graup, Vera, Best, Serena M., and Cameron, Ruth E.
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materials science ,collagen ,tissue engineering ,cardiac ,heart ,polymers ,natural polymers ,heart disease ,freeze drying ,architecture ,scaffold ,tissue mimicking ,modelling ,crosslinking ,cell invasion - Abstract
The ideal scaffold for tissue engineering provides an architecture similar to natural tissue. For cardiac tissue repair, this three dimensional environment can be modelled on the myocardial extracellular matrix (ECM). To approximate the material composition of the ECM, collagen type I can be used, as it constitutes the majority of the cardiac ECM in vivo. Furthermore, it can be easily extracted and processed, and offers a range of potential cell binding motifs. However, although its biophysical properties can be controlled via cross-linking, recent reports have suggested that this process has detrimental effects on bioactivity. The aim of this work is to optimise the properties of collagen scaffolds, modelled on the cardiac ECM, by varying cross-linking and freeze-drying conditions and thereby create an environment in which cardiomyocytes exhibit physiological behaviour. As its starting point, this thesis investigates porcine myocardial ECM. Tissue was decellularised using a combination of chemical and physical agents and the architecture and biophysical properties of the resulting cell-free samples were characterised. It was found that these samples comprised interconnected, isotropic pore structures, showed the capacity to swell i.e. increase their weight by) 2,800 % in 14 days, exhibited no mass loss over 14 days and had a Young's modulus (E) of 8.0 +/- 0.4 kPa. To mimic the observed properties, bovine collagen type I (Collagen Solutions, plc) was freeze-dried to produce isotropic pores and stabilised using a N-hydroxy-succinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimidehydrochloride, (NHS/EDC) cross-linking protocol. It was hypothesised that by tailoring the degree of cross-linking, the biophysical properties of the scaffolds could be modified to match the properties observed in the cardiac ECM. A mass of 0.69 g of NHS and 1.15 g of EDC, when combined in 100 ml of 96 % ethanol was defined as a cross-linking solution of 100 % concentration (100 % XL). Based on this definition, scaffolds were treated using solutions diluted to 10 %, 3 % and 1 %. Samples treated in 96 % ethanol alone, were defined as 0 % XL. It was found that while 100 % XL scaffolds possessed properties most similar to the ECM (swelling capacity of 4,200 % , mass loss of 10.8 % over 14 days, E = 6.9 +/- 0.5 kPa), cells showed limited attachment and survival at this cross-linking degree. By comparison, on 3 % XL samples, cell attachment and survival were significantly improved. In addition, the 3 % XL samples possessed sufficient stability to be used in cell culture (swelling capacity of 4,500 %, mass loss of 32.8 % over 14 days, E = 3.6 +/- 0.2 kPa). In vivo, cardiomyocytes have a spindle-shaped morphology and populate elongated, anisotropic pores. It was hypothesised that this porous structure could be imitated by imposing increased temperature gradients on the collagen suspension during freezing. Finite element modelling was used to simulate the freeze-drying process and indicated that the temperature gradient during freezing could be increased from 4.4 °C to 23 °C, over the 10 mm sample height, using polycarbonate moulds with conductive bases. Experimentally this led to successful creation of scaffolds with anisotropic pores and demonstrated that temperature gradient is ultimately responsible for anisotropic pore architecture. In a final set of experiments, isotropic and anisotropic 3 % XL scaffolds were seeded, in two different experiments, with either myoblasts or hESC-derived cardiomyocytes. The myoblast cell line was used to investigate cell access to the scaffolds and it was found that cells were able to invade isotropic scaffolds. However, in anisotropic scaffolds with horizontally aligned pores, invasion was limited to the top 60 µm of the samples, leading to an increased cell density in this area. This was subsequently confirmed with the hESC-derived cardiomyocytes. Seven days after cell seeding, isotropic scaffolds showed non-coordinated contractions, while anisotropic scaffolds with horizontally aligned pores, exhibited large-scale, coordinated contractions in the high cell density areas, deforming scaffolds up to 1170 nm over a length of 10 mm along the direction of the pores. It has been demonstrated that, based on the characteristics of the cardiac ECM, three-dimensional scaffolds can be created which allow cardiomyocytes to connect and exhibit physiological behaviour. These scaffolds show considerable potential in the field of regenerative medicine and the insights gained during their development will contribute significantly to the further advancement of the field.
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- 2019
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3. Efficacy and Safety of Leadless Pacemaker Implantation in Octogenarians
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Hofer, Daniel; https://orcid.org/0000-0001-8164-6329, Regoli, François; https://orcid.org/0000-0002-5936-4656, Saguner, Ardan M; https://orcid.org/0000-0003-1896-0803, Conte, Giulio, Jelisejevas, Julius, Luce Caputo, Maria, Graup, Vera; https://orcid.org/0000-0002-4626-5536, Grazioli Gauthier, Lorenzo, Gasperetti, Alessio; https://orcid.org/0000-0003-3432-070X, Steffel, Jan; https://orcid.org/0000-0002-1477-9153, Auricchio, Angelo; https://orcid.org/0000-0003-2116-6993, Breitenstein, Alexander; https://orcid.org/0000-0002-4440-2947, Hofer, Daniel; https://orcid.org/0000-0001-8164-6329, Regoli, François; https://orcid.org/0000-0002-5936-4656, Saguner, Ardan M; https://orcid.org/0000-0003-1896-0803, Conte, Giulio, Jelisejevas, Julius, Luce Caputo, Maria, Graup, Vera; https://orcid.org/0000-0002-4626-5536, Grazioli Gauthier, Lorenzo, Gasperetti, Alessio; https://orcid.org/0000-0003-3432-070X, Steffel, Jan; https://orcid.org/0000-0002-1477-9153, Auricchio, Angelo; https://orcid.org/0000-0003-2116-6993, and Breitenstein, Alexander; https://orcid.org/0000-0002-4440-2947
- Abstract
INTRODUCTION Long-term complication rates in standard transvenous pacemakers are reported around 4-12% with a higher incidence in the elderly population. We report our experience in octogenarians undergoing leadless pacemaker implantation in two large-volume centers in Switzerland. METHODS Consecutive patients undergoing leadless pacemaker implantation at two Swiss large volume centers (University Hospital Zurich, Zurich and Cardiocentro Ticino Institute, Lugano) between October 2015 and March 2020 were included in this retrospective analysis. Demographic information, clinical data, and procedural characteristics were recorded at the day of implantation and during follow-up. RESULTS Two hundred and twenty patients (mean age 80.6 ± 7.7 years, male 66%) were included. The main indication for pacemaker implantation was slow ventricular rate atrial fibrillation (111 of 220 patients, 50.4%). Out of the 220 patients, 124 (56.3%) were ≥80 years. Overall successful implantation rate was 98.6%. In the octogenarian population, the median procedure time (45 ± 20.2 min vs. 40 ± 19.6 min, p = 0.03) and radiation duration (6.1 ± 8.2 min vs. 5.0 ± 7.2 min, p = 0.03) were longer compared to patients <80 years. Major complications (2.7%, n = 6) and device measurements during follow-up were similar between patients ≥80 and <80 years. CONCLUSION Implantation of a leadless pacemaker device in octogenarians is safe and effective with a similarly low complication rate compared to non-octogenarians.
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- 2023
4. Efficacy and Safety of Leadless Pacemaker Implantation in Octogenarians.
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Hofer, Daniel, Regoli, François, Saguner, Ardan M., Conte, Giulio, Jelisejevas, Julius, Luce Caputo, Maria, Graup, Vera, Grazioli Gauthier, Lorenzo, Gasperetti, Alessio, Steffel, Jan, Auricchio, Angelo, and Breitenstein, Alexander
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OCTOGENARIANS ,CARDIAC pacemakers ,OLDER people ,ATRIAL fibrillation ,UNIVERSITY hospitals - Abstract
Introduction: Long-term complication rates in standard transvenous pacemakers are reported around 4–12% with a higher incidence in the elderly population. We report our experience in octogenarians undergoing leadless pacemaker implantation in two large-volume centers in Switzerland. Methods: Consecutive patients undergoing leadless pacemaker implantation at two Swiss large volume centers (University Hospital Zurich, Zurich and Cardiocentro Ticino Institute, Lugano) between October 2015 and March 2020 were included in this retrospective analysis. Demographic information, clinical data, and procedural characteristics were recorded at the day of implantation and during follow-up. Results: Two hundred and twenty patients (mean age 80.6 ± 7.7 years, male 66%) were included. The main indication for pacemaker implantation was slow ventricular rate atrial fibrillation (111 of 220 patients, 50.4%). Out of the 220 patients, 124 (56.3%) were ≥80 years. Overall successful implantation rate was 98.6%. In the octogenarian population, the median procedure time (45 ± 20.2 min vs. 40 ± 19.6 min, p = 0.03) and radiation duration (6.1 ± 8.2 min vs. 5.0 ± 7.2 min, p = 0.03) were longer compared to patients <80 years. Major complications (2.7%, n = 6) and device measurements during follow-up were similar between patients ≥80 and <80 years. Conclusion: Implantation of a leadless pacemaker device in octogenarians is safe and effective with a similarly low complication rate compared to non-octogenarians. [ABSTRACT FROM AUTHOR]
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- 2023
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5. Feasibility, Efficiency, and Safety of Zero-Fluoroscopy Catheter Interventions for Right-Sided Cardiac Arrhythmias Using Only Electroanatomic Mapping
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Hofer, Daniel, Steffel, Jan, Duru, Firat, Graup, Vera, Sasse, Tom, Saguner, Ardan, Breitenstein, Alexander, Hofer, Daniel, Steffel, Jan, Duru, Firat, Graup, Vera, Sasse, Tom, Saguner, Ardan, and Breitenstein, Alexander
- Abstract
INTRODUCTION Fluoroscopy is traditionally used for catheter interventions in electrophysiology but carries a long-term health risk. Besides additional invasive procedures to achieve zero-fluoroscopy (ZF) interventions, electroanatomic mapping may be an alternative to fluoroscopy without the need of additional procedures. We aimed to investigate the feasibility, safety, and efficiency of a ZF approach using only electroanatomic mapping (ZF) compared to a conventional fluoroscopic (CF) approach for patients with right sided cardiac arrhythmias. METHODS We performed a single centre retrospective cohort study of consecutive patients undergoing catheter interventions for electrophysiologic procedures from January 2019 to December 2020. Patients with left-sided arrhythmias, focal cryoablation, implanted endocardial devices, or additional interventions requiring fluoroscopy were excluded. RESULTS 202 patients underwent a ZF and 126 patients underwent a CF approach for right-sided cardiac arrhythmias. Apart from atrial fibrillation (ZF 16% vs. CF 9%, p = 0.044), baseline demographics were similar in both groups. Acute success rate was 100% in the ZF group and 97.9% in the CF group. Mean procedure time was lower in the ZF group (70 ± 36 vs. 87 ± 44 min, p = 0.0001), while ablation time (356 ± 324 vs. 320 ± 294 s, p = 0.157) was similar. Total complication rate was low in general (1.0 % major, 2% minor complications) and without a difference between both groups. CONCLUSION A ZF approach using only electroanatomic mapping without additional invasive procedures to diagnose and treat right-sided cardiac arrhythmias is feasible, efficient, and safe.
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- 2022
6. Feasibility, Efficiency, and Safety of Zero-Fluoroscopy Catheter Interventions for Right-Sided Cardiac Arrhythmias Using Only Electroanatomic Mapping
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Hofer, Daniel, primary, Steffel, Jan, additional, Duru, Firat, additional, Graup, Vera, additional, Sasse, Tom, additional, Saguner, Ardan, additional, and Breitenstein, Alexander, additional
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- 2022
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7. Unravelling Form and Function: Improved function of engineered cardiac tissue through extra-cellular anisotropy
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Cyr, Jamie A., primary, Colzani, Maria, additional, Bayraktar, Semih, additional, Graup, Vera, additional, Farndale, Richard, additional, Sinha, Sanjay, additional, Best, Serena M., additional, and Cameron, Ruth E., additional
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- 2021
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8. Conservative Treatment of Unicuspid Aortic Valve with Newly Diagnosed Type A Aortic Dissection
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Graup, Vera; https://orcid.org/0000-0002-4626-5536, Meier, Lukas, Maisano, Francesco, Ouda, Ahmed, Graup, Vera; https://orcid.org/0000-0002-4626-5536, Meier, Lukas, Maisano, Francesco, and Ouda, Ahmed
- Abstract
We present a case of a 36-year-old male patient with known arthrogryposis multiplex congenita and an associated unicuspid aortic valve. The patient later developed a significant aneurysm of the ascending aorta, however refused surgical intervention and missed follow-up appointments for 5 years. During an urgent, general practitioner-initiated transthoracic echocardiography follow-up, a chronic type A aortic dissection was diagnosed as a result of progressive aortic dilatation. Due to the stationary pressure gradients and non-progressive leaflet fibrosis, a conservative approach for to the unicuspid aortic valve was chosen, combined with replacement of the ascending aorta and partial replacement of the aortic arch.
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- 2020
9. Conservative Treatment of Unicuspid Aortic Valve with Newly Diagnosed Type A Aortic Dissection
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Graup, Vera, primary, Meier, Lukas, additional, Maisano, Francesco, additional, and Ouda, Ahmed, additional
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- 2020
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10. Conservative Treatment of Unicuspid Aortic Valve with Newly Diagnosed Type A Aortic Dissection
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Ahmed Ouda, Francesco Maisano, Vera Graup, Lukas E. Meier, University of Zurich, and Graup, Vera
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Adult ,Male ,Aortic arch ,Aortic valve ,Heart Defects, Congenital ,medicine.medical_specialty ,Aortic Valve Disease 1 ,RD1-811 ,Heart Valve Diseases ,Aortic Diseases ,Case Report ,610 Medicine & health ,Aorta, Thoracic ,030204 cardiovascular system & hematology ,Conservative Treatment ,2705 Cardiology and Cardiovascular Medicine ,03 medical and health sciences ,0302 clinical medicine ,Aneurysm ,medicine.artery ,Ascending aorta ,medicine ,Diseases of the circulatory (Cardiovascular) system ,Humans ,Thoracic aorta ,Heart Valve Prosthesis Implantation ,Aortic dissection ,Arthrogryposis multiplex congenita ,business.industry ,General Medicine ,medicine.disease ,Dilatation ,Unicuspid aortic valve ,2746 Surgery ,Surgery ,Aortic Dissection ,medicine.anatomical_structure ,RC666-701 ,Aortic Valve ,10209 Clinic for Cardiology ,cardiovascular system ,Cardiology and Cardiovascular Medicine ,business - Abstract
We present a case of a 36-year-old male patient with known arthrogryposis multiplex congenita and an associated unicuspid aortic valve. The patient later developed a significant aneurysm of the ascending aorta, however refused surgical intervention and missed follow-up appointments for 5 years. During an urgent, general practitioner-initiated transthoracic echocardiography follow-up, a chronic type A aortic dissection was diagnosed as a result of progressive aortic dilatation. Due to the stationary pressure gradients and non-progressive leaflet fibrosis, a conservative approach for to the unicuspid aortic valve was chosen, combined with replacement of the ascending aorta and partial replacement of the aortic arch.
- Published
- 2020
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