المؤلفون: Pigot, Harry, Soltesz, Kristian, Steen, Stig

المساهمون: Ishikawa, Kiyotake, Editor

المصدر: Experimental Models of Cardiovascular Diseases : Methods and Protocols - Methods and Protocols. 2803:87-107

مصطلحات موضوعية: Working porcine heart, Isolated heart preparation, Functional heart evaluation, cardiac afterload, cyber-physiological systems, functional heart assessment, ex vivo heart perfusion, ex situ heart perfusion, ex vivo heart evaluation, heart transplantation, Teknik, Medicinteknik, Medicinsk apparatteknik, Engineering and Technology, Medical Engineering, Medical Equipment Engineering, Medicin och hälsovetenskap, Medicinsk bioteknologi, Medical and Health Sciences, Medical Biotechnology, Klinisk medicin, Kardiologi, Clinical Medicine, Cardiac and Cardiovascular Systems, Elektroteknik och elektronik, Reglerteknik, Electrical Engineering, Electronic Engineering, Information Engineering, Control Engineering

الوصف: Ex vivo working porcine heart models allow for the study of a heart’s function and physiology outside the living organism. These models are particularly useful due to the anatomical and physiological similarities between porcine and human hearts, providing an experimental platform to investigate cardiac disease or assess donor heart viability for transplantation. This chapter presents an in-depth discussion of the model’s components, including the perfusate, preload, and afterload. We explore the challenges of emulating cardiac afterload and present a historical perspective on afterload modeling, discussing various methodologies and their respective limitations. An actively controlled afterload device is introduced to enhance the model’s ability to rapidly adjust pressure in the large arteries, thereby providing a more accurate and dynamic experimental model. Finally, we provide a comprehensive experimental protocol for the ex vivo working porcine heart model.

الوصول الحر: https://lup.lub.lu.se/record/0a288de4-1f77-40f6-a77c-3b3173b6861aTest
http://dx.doi.org/10.1007/978-1-0716-3846-0_7Test

المؤلفون: Mads Dam Lyhne, Jacob Gammelgaard Schultz, Christian Schmidt Mortensen, Anders Kramer, Jens Erik Nielsen-Kudsk, Asger Andersen

المصدر: BMC Pulmonary Medicine, Vol 24, Iss 1, Pp 1-9 (2024)

مصطلحات موضوعية: Right ventricular function, Pulmonary circulation, Right ventricular afterload, Ventilation-perfusion mismatch, Gas exchange, Animal model, Diseases of the respiratory system, RC705-779

الوصف: Abstract Background Acute pulmonary embolism (PE) induces ventilation-perfusion mismatch and hypoxia and increases pulmonary pressure and right ventricular (RV) afterload, entailing potentially fatal RV failure within a short timeframe. Cardiopulmonary factors may respond differently to increased clot burden. We aimed to elucidate immediate cardiopulmonary responses during successive PE episodes in a porcine model. Methods This was a randomized, controlled, blinded study of repeated measurements. Twelve pigs were randomly assigned to receive sham procedures or consecutive PEs every 15 min until doubling of mean pulmonary pressure. Cardiopulmonary assessments were conducted at 1, 2, 5, and 13 min after each PE using pressure-volume loops, invasive pressures, and arterial and mixed venous blood gas analyses. ANOVA and mixed-model statistical analyses were applied. Results Pulmonary pressures increased after the initial PE administration (p

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/1471-2466Test

الوصول الحر: https://doaj.org/article/2aff277517ee4fabab944f76a2c178a9Test

المؤلفون: Pigot, Harry

مصطلحات موضوعية: physiological modelling, cardiac afterload, heart assessment, working heart, simulation, control of physiological and clinical variables, Teknik, Elektroteknik och elektronik, Reglerteknik, Engineering and Technology, Electrical Engineering, Electronic Engineering, Information Engineering, Control Engineering

الوصف: Heart transplantation is a life-saving procedure for patients with end-stage heart failure. However, conservative acceptance criteria result in most donated hearts being discarded. Enabling clinicians to assess heart function after organ procurement can pave the way for the safe use of hearts that are currently rejected. This thesis focuses on improving techniques for the direct, controlled assessment of a recovered heart's hemodynamic performance. The first paper reviews ex situ working heart models and cardiac afterload devices, discussing challenges in emulating cardiac afterload and detailing an experimental method for a working porcine heart model. Paper II analyzes Windkessel models, which are the standard cardiac afterload model. It assesses their applicability and limitations, and presents a method for identifying model parameters from sampled data. The analysis concludes that complex models like the 4-element Windkessel model are not identifiable from relevant experimental data. The third paper reformulates traditional Windkessel models for a more accurate representation of hemodynamic responses. Using power as model input, the paper offers a more physiological representation of the hemodynamic response to various afterloads, aiding in afterload device design. In Paper IV, the efficacy of a pneumatic afterload device creating a range of physiological loading conditions is investigated in six porcine hearts. The experiments show the concept's utility in testing hearts under multiple conditions. Paper V introduces an actively controlled variable flow resistance, demonstrating its ability to reproduce a wide range of afterload dynamics while enforcing safe pressure limits for heart assessment. The afterload concept, outlined in Paper I, is investigated in silico using the methods from Paper III. A physical prototype and pilot experiments led to a patent submission for the design. These papers advance functional heart assessment by both refining Windkessel-model-based simulation tools (Papers II and III) and exploring novel afterload device concepts (Papers I, IV, and V). Together, they constitute a step towards clinical implementation of technology that can safely enable more transplantations by providing an improved basis for decision-making.

وصف الملف: electronic

الوصول الحر: https://lup.lub.lu.se/record/cb77137c-2a2d-48c3-9461-d9baf01d999eTest
https://portal.research.lu.se/files/171584891/Henry_Pigot_-_thesis.pdfTest

المؤلفون: Pigot, Henry, Soltesz, Kristian, Paskevicius, Audrius, Liao, Qiuming, Sjöberg, Trygve, Steen, Stig

المصدر: Artificial Organs. 46(9):1794-1803

مصطلحات موضوعية: cardiac afterload, ex vivo heart evaluation, functional evaluation, heart perfusion, heart transplantation, working heart, Teknik, Medicinteknik, Medicinsk apparatteknik, Engineering and Technology, Medical Engineering, Medical Equipment Engineering, Medicinsk laboratorie- och mätteknik, Medical Laboratory and Measurements Technologies

الوصف: Background: Existing working heart models for ex vivo functional evaluation of donor hearts often use cardiac afterloads made up of discrete resistive and compliant elements. This approach limits the practicality of independently controlling systolic and diastolic aortic pressure to safely test the heart under multiple loading conditions. We present and investigate a novel afterload concept designed to enable such control. Methods: Six ∼70 kg pig hearts were evaluated in vivo, then ex vivo in left-ventricular working mode using the presented afterload. Both in vivo and ex vivo, the hearts were evaluated at two exertion levels: at rest and following a 20 μg adrenaline bolus, while measuring aortic pressure and flow, left ventricular pressure and volume, and left atrial pressure. Results: The afterload gave aortic pressure waveforms that matched the general shape of the in vivo measurements. A wide range of physiological systolic pressures (93 to 160 mm Hg) and diastolic pressures (73 to 113 mm Hg) were generated by the afterload. Conclusions: With the presented afterload concept, multiple physiological loading conditions could be tested ex vivo, and compared with the corresponding in vivo data. An additional control loop from the set pressure limits to the measured systolic and diastolic aortic pressure is proposed to address discrepancies observed between the set limits and the measured pressures.

الوصول الحر: https://lup.lub.lu.se/record/22e47e0e-5826-4a1a-b0d3-1ac86aec9a4cTest
http://dx.doi.org/10.1111/aor.14307Test

المؤلفون: Rody G. Bou Chaaya, Taha Hatab, Sahar Samimi, Fatima Qamar, Chloe Kharsa, Joe Aoun, Nadeen Faza, Stephen H. Little, Marvin D. Atkins, Michael J. Reardon, Neal S. Kleiman, Sherif F. Nagueh, William A. Zoghbi, Ashrith Guha, Syed Zaid, Sachin S. Goel

المصدر: Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, Vol 13, Iss 8 (2024)

مصطلحات موضوعية: mitral regurgitation, mitral transcatheter edge‐to‐edge repair, pulmonary effective arterial elastance, pulmonary hypertension, right ventricular afterload, Diseases of the circulatory (Cardiovascular) system, RC666-701

الوصف: Background Pulmonary hypertension (PH) and secondary mitral regurgitation (MR) are associated with adverse outcomes after mitral transcatheter edge‐to‐edge repair. We aim to study the prognostic value of invasively measured right ventricular afterload in patients undergoing mitral transcatheter edge‐to‐edge repair. Methods and Results We identified patients who underwent right heart catheterization ≤1 month before transcatheter edge‐to‐edge repair. The end points were all‐cause mortality and a composite of mortality and heart failure hospitalization at 2 years. Using the receiver operating characteristic curve–derived threshold of 0.6 for pulmonary effective arterial elastance ([Ea], pulmonary artery systolic pressure/stroke volume), patients were stratified into 3 profiles based on PH severity (low elastance [HE]: Ea

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2047-9980Test

الوصول الحر: https://doaj.org/article/a72f50da69244c9e94fba5318a050261Test

المؤلفون: Vizza, Carmine Dario, Lang, Irene M, Badagliacca, Roberto, Benza, Raymond L, Rosenkranz, Stephan, White, R James, Adir, Yochai, Andreassen, Arne K, Balasubramanian, Vijay, Bartolome, Sonja, Blanco, Isabel, Bourge, Robert C, Carlsen, Jørn, Camacho, Rafael Enrique Conde, D’Alto, Michele, Farber, Harrison W, Frantz, Robert P, Ford, H James, Ghio, Stefano, Gomberg-Maitland, Mardi, Humbert, Marc, Naeije, Robert, Orfanos, Stylianos E, Oudiz, Ronald J, Perrone, Sergio V, Shlobin, Oksana A, Simon, Marc A, Sitbon, Olivier, Torres, Fernando, Vachiery, Jean Luc, Wang, Kuo-Yang, Yacoub, Magdi H, Liu, Yan, Golden, Gil, Matsubara, Hiromi

المصدر: American Journal of Respiratory and Critical Care Medicine. 205(7)

مصطلحات موضوعية: Clinical Research, Lung, Cardiovascular, Rare Diseases, 6.1 Pharmaceuticals, Evaluation of treatments and therapeutic interventions, Heart Ventricles, Humans, Hypertension, Pulmonary, Middle Aged, Pulmonary Arterial Hypertension, Pulmonary Artery, Retrospective Studies, Ventricular Dysfunction, Right, Ventricular Function, Right, combination therapy, prostacyclin, pulmonary arterial hypertension, pulmonary arterial pressure, right ventricular afterload, Medical and Health Sciences, Respiratory System

الوصف: Despite numerous therapeutic advances in pulmonary arterial hypertension, patients continue to suffer high morbidity and mortality, particularly considering a median age of 50 years. This article explores whether early, robust reduction of right ventricular afterload would facilitate substantial improvement in right ventricular function and thus whether afterload reduction should be a treatment goal for pulmonary arterial hypertension. The earliest clinical studies of prostanoid treatment in pulmonary arterial hypertension demonstrated an important link between lowering mean pulmonary arterial pressure (or pulmonary vascular resistance) and improved survival. Subsequent studies of oral monotherapy or sequential combination therapy demonstrated smaller reductions in mean pulmonary arterial pressure and pulmonary vascular resistance. More recently, retrospective reports of initial aggressive prostanoid treatment or initial combination oral and parenteral therapy have shown marked afterload reduction along with significant improvements in right ventricular function. Some data suggest that reaching threshold levels for pressure or resistance (components of right ventricular afterload) may be key to interrupting the self-perpetuating injury of pulmonary vascular disease in pulmonary arterial hypertension and could translate into improved long-term clinical outcomes. Based on these clues, the authors postulate that improved clinical outcomes might be achieved by targeting significant afterload reduction with initial oral combination therapy and early parenteral prostanoids.

وصف الملف: application/pdf

الوصول الحر: https://escholarship.org/uc/item/9jx353xnTest

المؤلفون: Sinan Osman, Natasha R. Girdharry, Elizabeth Karvasarski, Robert F. Bentley, Stephen P. Wright, Nadia Sharif, Micheal McInnis, John T. Granton, Marc dePerrot, Susanna Mak

المصدر: Pulmonary Circulation, Vol 14, Iss 1, Pp n/a-n/a (2024)

مصطلحات موضوعية: afterload, right heart catheterization, Diseases of the circulatory (Cardiovascular) system, RC666-701, Diseases of the respiratory system, RC705-779

الوصف: Abstract Chronic thromboembolic pulmonary disease (CTEPD) is characterized by organized nonresolving thrombi in pulmonary arteries (PA). In CTEPD with pulmonary hypertension (PH), chronic thromboembolic PH (CTEPH), early wave reflection results in abnormalities of pulsatile afterload and augmented PA pressures. We hypothesized that exercise during right heart catheterization (RHC) would elicit more frequent elevations of pulsatile vascular afterload than resistive elevations in patients with CTEPD without PH. The interdependent physiology of pulmonary venous and PA hemodynamics was also evaluated. Consecutive patients with CTEPD without PH (resting mean PA pressure ≤20 mmHg) undergoing an exercise RHC were identified. Latent resistive and pulsatile abnormalities of pulmonary vascular afterload were defined as an exercise mean PA pressure/cardiac output >3 WU, and PA pulse pressure to PA wedge pressure (PA PP/PAWP) ratio >2.5, respectively. Forty‐five patients (29% female, 53 ± 14 years) with CTEPD without PH were analyzed. With exercise, 19 patients had no abnormalities (ExNOR), 26 patients had abnormalities (ExABN) of pulsatile (20), resistive (2), or both (4) elements of pulmonary vascular afterload. Exercise elicited elevations of pulsatile afterload (53%) more commonly than resistive afterload (13%) (p

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2045-8940Test

الوصول الحر: https://doaj.org/article/aaf17d2e8dad44da8211f78bc4154d8aTest

المؤلفون: Arrigo, Mattia, Price, Susanna, Harjola, Veli-Pekka, Huber, Lars C, SCHAUBROECK, HANNAH, Vieillard-Baron, Antoine, Mebazaa, Alexandre, Masip, Josep

المصدر: EUROPEAN HEART JOURNAL-ACUTE CARDIOVASCULAR CARE ; ISSN: 2048-8726 ; ISSN: 2048-8734

مصطلحات موضوعية: Medicine and Health Sciences, Cardiology and Cardiovascular Medicine, Critical Care and Intensive Care Medicine, General Medicine, ARDS, Pulmonary embolism, Pulmonary hypertension, Increased afterload, Acute heart failure, Cardiogenic shock, Cor pulmonale, Right heart failure, Right ventricular failure

الوصف: Acute right ventricular failure secondary to acutely increased right ventricular afterload (acute cor pulmonale) is a life-threatening condition that may arise in different clinical settings. Patients at risk of developing or with manifest acute cor pulmonale usually present with an acute pulmonary disease (e.g. pulmonary embolism, pneumonia, and acute respiratory distress syndrome) and are managed initially in emergency departments and later in intensive care units. According to the clinical setting, other specialties are involved (cardiology, pneumology, internal medicine). As such, coordinated delivery of care is particularly challenging but, as shown during the COVID-19 pandemic, has a major impact on prognosis. A common framework for the management of acute cor pulmonale with inclusion of the perspectives of all involved disciplines is urgently needed. Graphical Abstract Management of acute cor pulmonale. ARDS, acute respiratory distress syndrome; LVAD, left ventricular assist device; PDE-III-I, phosphodiesterase-III inhibitors; RV, right ventricle; ECMO, extracorporeal membrane oxygenation.

وصف الملف: application/pdf

العلاقة: https://biblio.ugent.be/publication/01HQTQXMXQMBPYWC4KZ2SGR1D9Test; http://hdl.handle.net/1854/LU-01HQTQXMXQMBPYWC4KZ2SGR1D9Test; http://doi.org/10.1093/ehjacc/zuad157Test; https://biblio.ugent.be/publication/01HQTQXMXQMBPYWC4KZ2SGR1D9/file/01HS8KCHYY08MGJB56SGYX29WATest

الإتاحة: https://doi.org/10.1093/ehjacc/zuad157Test
https://biblio.ugent.be/publication/01HQTQXMXQMBPYWC4KZ2SGR1D9Test
http://hdl.handle.net/1854/LU-01HQTQXMXQMBPYWC4KZ2SGR1D9Test
https://biblio.ugent.be/publication/01HQTQXMXQMBPYWC4KZ2SGR1D9/file/01HS8KCHYY08MGJB56SGYX29WATest

المؤلفون: Pigot, Harry, Soltesz, Kristian

المصدر: American Control Conference, 2022,GA, United States,-- 2022 American Control Conference (ACC) ELLIIT: the Linköping-Lund initiative on IT and mobile communication. :3006-3011

مصطلحات موضوعية: Modelling and simulation, cardiac afterload, heart evaluation, differential-algebraic equation, Teknik, Medicinteknik, Annan medicinteknik, Engineering and Technology, Medical Engineering, Other Medical Engineering, Elektroteknik och elektronik, Reglerteknik, Electrical Engineering, Electronic Engineering, Information Engineering, Control Engineering

الوصف: The lack of methods to evaluate mechanical function of donated hearts in the context of transplantation imposes large precautionary margins, translating into a low utilization rate of donor organs. This has spawned research into cyber-physical models constituting artificial afterloads (arterial trees), that can serve to evaluate the contractile capacity of the donor heart.The Windkessel model is an established linear time-invariant afterload model, that researchers committed to creating a cyber-physical afterload have used as a template. With aortic volumetric flow as input and aortic pressure as output, it is not directly obvious how a Windkessel model will respond to changes in heart contractility.We transform the classic Windkessel model to relate power, rather than flow, to pressure. This alters the model into a differential-algebraic equation, albeit one that is straightforward to simulate. We then propose a power signal model, that is based on pressure and flow measurements and optimal in a Bayesian sense within the class of C2 signals. Finally, we show how the proposed signal model can be used to create relevant simulation scenarios, and use this to illustrate why it is problematic to use the Windkessel model as a basis for designing a clinically relevant artificial afterload.

وصف الملف: electronic

الوصول الحر: https://lup.lub.lu.se/record/1f769e42-89b0-435e-9edf-4366b90977faTest
https://portal.research.lu.se/files/115310976/pigot2022differential.pdfTest
http://dx.doi.org/10.23919/ACC53348.2022.9867889Test

المؤلفون: Farhan Raza, Naomi C. Chesler

المصدر: Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, Vol 12, Iss 20 (2023)

مصطلحات موضوعية: Editorials, distensibility, invasive cardiopulmonary exercise test, pulmonary impedance, pulsatile right ventricular afterload, Diseases of the circulatory (Cardiovascular) system, RC666-701

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2047-9980Test

الوصول الحر: https://doaj.org/article/6ec8e5aba4844886a0b368bc764cbe54Test