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148 results on '"Bajona, Pietro"'

3. Regional biaxial mechanical data of the mitral and tricuspid valve anterior leaflets.

Author

Laurence, Devin, Ross, Colton, Jett, Samuel, Johns, Cortland, Echols, Allyson, Baumwart, Ryan, Towner, Rheal, Liao, Jun, Bajona, Pietro, Wu, Yi, and Lee, Chung-Hao

Subjects
Atrioventricular heart valve biomechanics, Biaxial mechanical testing, Regionally-varied mechanical properties
Abstract

The collective data associated with this article presents the biaxial mechanical behavior for six smaller, delimited regions of the mitral valve and tricuspid valve anterior leaflets. Each data set consists of five columns of data, specifically: (i) biaxial testing protocol ID, (ii) circumferential stretch, (iii) radial stretch, (iv) circumferential membrane tension, and (v) radial membrane tension. For further elaboration regarding methodologies or results of the biaxial mechanical characterization please refer to the companion article Laurence, 2019.

Published
2019

4. An investigation of regional variations in the biaxial mechanical properties and stress relaxation behaviors of porcine atrioventricular heart valve leaflets.

Author

Laurence, Devin, Ross, Colton, Jett, Samuel, Johns, Cortland, Echols, Allyson, Baumwart, Ryan, Towner, Rheal, Liao, Jun, Bajona, Pietro, Wu, Yi, and Lee, Chung-Hao

Subjects
Biaxial mechanical testing, Heart valve biomechanics, Regional mechanical properties, The mitral valve, The tricuspid valve, Animals, Anisotropy, Biomechanical Phenomena, Heart Atria, Heart Valves, Heart Ventricles, Models, Cardiovascular, Stress, Mechanical, Swine
Abstract

The facilitation of proper blood flow through the heart depends on proper function of heart valve components, and alterations to any component can lead to heart disease or failure. Comprehension of these valvular diseases is reliant on thorough characterization of healthy heart valve structures for use in computational models. Previously, computational models have treated these leaflet structures as a structurally and mechanically homogenous material, which may not be an accurate description of leaflet mechanical response. In this study, we aimed to characterize the mechanics of the heart valve leaflet as a structurally heterogenous material. Specifically, porcine mitral valve and tricuspid valve anterior leaflets were sectioned into six regions and biaxial mechanical tests with various loading ratios and stress-relaxation test were performed on each regional tissue sample. Three main findings from this study were summarized as follows: (i) the central regions of the leaflet had a more anisotropic nature than edge regions, (ii) the mitral valve anterior leaflet was more extensible in regions closer to the annulus, and (iii) there was variance in the stress-relaxation behavior among all six regions, with mitral valve leaflet tissue regions exhibiting a greater decay than the tricuspid valve regions. This study presents a novel investigation of the regional variations in the heart valve biomechanics that has not been comprehensively examined. Our results thus allow for a refinement of computational models for more accurately predicting diseased or surgically-intervened condition, where tissue heterogeneity plays an essential role in the heart valve function.

Published
2019

11. Investigating the Transient Regenerative Potential of Cardiac Muscle Using a Neonatal Pig Partial Apical Resection Model

Author

Copeland, Katherine M., primary, Brazile, Bryn L., additional, Butler, J. Ryan, additional, Cooley, Jim, additional, Brinkman-Ferguson, Erin, additional, Claude, Andrew, additional, Lin, Sallie, additional, Rais-Rohani, Sammira, additional, Welch, Bradley, additional, McMahan, Sara R., additional, Nguyen, Kytai T., additional, Hong, Yi, additional, Ramaswamy, Sharan, additional, Liu, Zhi-Ping, additional, Bajona, Pietro, additional, Peltz, Matthias, additional, and Liao, Jun, additional

Published
2022
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12. CLINICAL PROFILE OF LOW FLOW VS. NORMAL FLOW HIGH GRADIENT HYPERTROPHIC CARDIOMYOPATHY PATIENTS UNDERGOING SEPTAL MYECTOMY

Author

Vashistha, Kirtivardhan, primary, Bajona, Pietro, additional, Doyle, Mark, additional, Biederman, Robert W.W., additional, Murali, Srinivas, additional, Elhamdani, Adee, additional, Alpert, Craig Michael, additional, Khurana, Abhas, additional, Farah, Victor, additional, Keeley, Jennifer, additional, Samra, Gursharan, additional, Mahabir, Sunita, additional, Noory, Ali J., additional, and Nguyen, Vinh Q., additional

Published
2022
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13. Structural and Biomechanical Characterizations of Acellular Porcine Mitral Valve Scaffolds: Anterior Leaflets, Posterior Leaflets, And Chordae Tendineae

Author

Wang, Bo, primary, Sierad, Leslie N., additional, Mercuri, Jeremy J., additional, Simionescu, Agneta, additional, Simionescu, Dan T., additional, Williams, Lakiesha, additional, Vela, Ryan, additional, Bajona, Pietro, additional, Peltz, Matthias, additional, Gonzalez, Brittany A., additional, Hong, Yi, additional, and Liao, Jun, additional

Published
2022
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19. Pig-to-baboon heterotopic heart transplantation – exploratory preliminary experience with pigs transgenic for human thrombomodulin and comparison of three costimulation blockade-based regimens

Author

Iwase, Hayato, Ekser, Burcin, Satyananda, Vikas, Bhama, Jay, Hara, Hidetaka, Ezzelarab, Mohamed, Klein, Edwin, Wagner, Robert, Long, Cassandra, Thacker, Jnanesh, Li, Jiang, Zhou, Hao, Jiang, Maolin, Nagaraju, Santosh, Zhou, Huidong, Veroux, Massimiliano, Bajona, Pietro, Wijkstrom, Martin, Wang, Yi, Phelps, Carol, Klymiuk, Nikolai, Wolf, Eckhard, Ayares, David, and Cooper, David K. C.

Published
2015
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24. LVOT OBSTRUCTION IN HYPERTROPHIC CARDIOMYOPATHY: DEEMPHASIZING VENTURI EFFECT AND FOCUSING ON LV FLOW VORTEX AND MITRAL LEAFLET EXCESS

Author

Khurana, Abhas, primary, Elhamdani, Adee, additional, Vashistha, Kirtivardhan, additional, Hu, Jian, additional, Biederman, Robert, additional, Farah, Victor, additional, Bajona, Pietro, additional, Alpert, Craig, additional, Murali, Srinivas, additional, Keeley, Jennifer, additional, and Nguyen, Vinh, additional

Published
2021
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28. The first 200 septal myectomies: Ensuring gold standard outcomes.

Author

Quintana, Eduard and Bajona, Pietro

Abstract

Objectives: Septal myectomy remains the gold standard treatment for symptomatic left ventricular outflow tract obstruction refractory to medical treatment. It is recommended that this operation be performed in dedicated hypertrophic obstructive cardiomyopathy centres by experienced surgeons. The septal myectomy option remains unavailable to many patients based solely on geography, including those who would clearly benefit more substantially from surgery than other therapeutic options. Here, we share our experience in starting new hypertrophic cardiomyopathy programmes. Methods: We retrospectively reviewed initial septal myectomy experiences at two hypertrophic cardiomyopathy programmes starting in 2014. Results: Two-hundred septal myectomies were performed. Mean age was 58.8 years and 51% were females. Advanced heart failure symptoms were present in 95.5% of patients and 23.5% had experienced syncope. Mean maximal intraventricular gradient was 89 mmHg and 48.5% underwent concomitant procedures at the time of septal myectomy. There was no perioperative (in-hospital or 30 days) mortality. Ninety-two per cent had provoked left ventricular gradients of ≤ 15 mmHg and 97% had none/mild mitral regurgitation at post-operative assessment. In our contemporary cohort, there were 2 (1%) intraoperative ventricular septal defects and 5% required a permanent pacemaker. Conclusions: Our early septal myectomy experience targeted a complex population, frequently in need of concomitant procedures. Abolition of left ventricular obstruction and resolution of systolic anterior motion mediated mitral regurgitation can be expected. The safety and efficacy of septal myectomy carried at hypertrophic cardiomyopathy centres by properly trained surgeons achieved the desired outcomes established by recent hypertrophic cardiomyopathy guidelines. [ABSTRACT FROM AUTHOR]

Published
2022
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29. Answers to reviewers from Epicardial prestrained confinement and residual stresses: a newly observed heart ventricle confinement interface

Author

Xiaodan Shi, Liu, Yue, Copeland, Katherine M., McMahan, Sara R., Zhang, Song, J. Ryan Butler, Hong, Yi, Cho, Michael, Bajona, Pietro, Huajian Gao, and Liao, Jun

Abstract

The heart epicardial layer, with elastin as the dominant component, has not been well investigated, specifically on how it contributes to ventricular biomechanics. In this study, we revealed and quantitatively assessed the overall status of prestraining and residual stresses exerted by the epicardial layer on the heart left ventricle (LV). During porcine heart wall dissection, we discovered that bi-layered LV surface strips, consisting of an epicardial layer and cardiac muscle, always curled towards the epicardial side due to epicardial residual stresses. We hence developed a curling angle characterization technique to intuitively and qualitatively reveal the location-dependency and direction-dependency of epicardial residual stresses. Moreover, by combining prestrain measurement and biaxial mechanical testing, we were able to quantify the epicardial prestrains and residual stresses on the unpressurized intact LV. To investigate the potential mechanical effect of epicardial prestraining, a finite-element (FE) model has been constructed, and we demonstrate that it is the prestraining of epicardial layer, not the epicardial layer alone, providing an additional resistance mechanism during LV diastolic expansion and ventricular wall protection by reducing myocardial stress. In short, our study on healthy, native porcine hearts has revealed an important phenomenon—the epicardial layer, rich in elastin, acts like a prestrained ‘balloon’ that wraps around the heart and functions as an extra confinement and protection interface. The obtained knowledge fills a gap in ventricular biomechanics and will help design novel biomimicking materials or prosthetic devices to target the maintenance/recreation of this ventricle confinement interface.

Published
2019
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30. Supplementary material from Epicardial prestrained confinement and residual stresses: a newly observed heart ventricle confinement interface

Author

Xiaodan Shi, Liu, Yue, Copeland, Katherine M., McMahan, Sara R., Zhang, Song, J. Ryan Butler, Hong, Yi, Cho, Michael, Bajona, Pietro, Huajian Gao, and Liao, Jun

Abstract

The heart epicardial layer, with elastin as the dominant component, has not been well investigated, specifically on how it contributes to ventricular biomechanics. In this study, we revealed and quantitatively assessed the overall status of prestraining and residual stresses exerted by the epicardial layer on the heart left ventricle (LV). During porcine heart wall dissection, we discovered that bi-layered LV surface strips, consisting of an epicardial layer and cardiac muscle, always curled towards the epicardial side due to epicardial residual stresses. We hence developed a curling angle characterization technique to intuitively and qualitatively reveal the location-dependency and direction-dependency of epicardial residual stresses. Moreover, by combining prestrain measurement and biaxial mechanical testing, we were able to quantify the epicardial prestrains and residual stresses on the unpressurized intact LV. To investigate the potential mechanical effect of epicardial prestraining, a finite-element (FE) model has been constructed, and we demonstrate that it is the prestraining of the epicardial layer, not the epicardial layer alone, providing an additional resistance mechanism during LV diastolic expansion and ventricular wall protection by reducing myocardial stress. In short, our study on healthy, native porcine hearts has revealed an important phenomenon—the epicardial layer, rich in elastin, acts like a prestrained ‘balloon’ that wraps around the heart and functions as an extra confinement and protection interface. The obtained knowledge fills a gap in ventricular biomechanics and will help design novel biomimicking materials or prosthetic devices to target the maintenance/recreation of this ventricle confinement interface.

Published
2019
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37. An investigation of regional variations in the biaxial mechanical properties and stress relaxation behaviors of porcine atrioventricular heart valve leaflets

Author

Laurence, Devin, primary, Ross, Colton, additional, Jett, Samuel, additional, Johns, Cortland, additional, Echols, Allyson, additional, Baumwart, Ryan, additional, Towner, Rheal, additional, Liao, Jun, additional, Bajona, Pietro, additional, Wu, Yi, additional, and Lee, Chung-Hao, additional

Published
2019
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38. Aims and expectations of a prospective multicenter study on aortic valve surgery: (E-AVR registry)

Author

Nicolini, Francesco, primary, Benassi, Filippo, additional, Gherli, Riccardo, additional, Musumeci, Francesco, additional, Mariscalco, Giovanni, additional, Ahmed, Aamer, additional, Murphy, Gavin J., additional, Girdauskas, Evaldas, additional, Reichenspurner, Hermann, additional, Quintana, Eduardo, additional, Castellà, Manuel, additional, Santini, Francesco, additional, Salsano, Antonio, additional, De Feo, Marisa, additional, Della Corte, Alessandro, additional, Bancone, Ciro, additional, Sponga, Sandro, additional, Livi, Ugolino, additional, Tozzi, Piergiorgio, additional, Perrotti, Andrea, additional, Chocron, Sidney, additional, Ruggieri, Vito, additional, Corbineau, Hervè, additional, Verhoye, Jean-Philippe, additional, Santarpino, Giuseppe, additional, Fischlein, Theodor, additional, Rinaldi, Mauro, additional, Salizzoni, Stefano, additional, Ferrari, Enrico, additional, Bajona, Pietro, additional, Abouliatim, Issam, additional, Faggian, Giuseppe, additional, Gherli, Tiziano, additional, Francica, Alessandra, additional, Lucarelli, Carla, additional, and Onorati, Francesco, additional

Published
2018
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39. Preface

Author

Bajona, Pietro, primary and Clarke, Nicholas, additional

Published
2017
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41. Hypertrophic obstructive cardiomyopathy: review of surgical treatment

Author

Price, Jonathan, primary, Clarke, Nicholas, additional, Turer, Aslan, additional, Quintana, Eduard, additional, Mestres, Carlos, additional, Huffman, Lynn, additional, Peltz, Matthias, additional, Wait, Michael, additional, Ring, W Steves, additional, Jessen, Michael, additional, and Bajona, Pietro, additional

Published
2017
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