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Thesis ; Online: Intelligent Rotary Blood Pumps with Physiological Response

Petrou, Anastasios

2018

Keywords	info:eu-repo/classification/ddc/610 ; Medical sciences ; medicine
Language	English
Publisher	ETH Zurich
Publishing country	ch
Document type	Thesis ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: In Vitro Investigation of Platelet Dysfunction Induced by Osmotic Pressure Variations.

Pantazi, Despoina / Stratou, Athina / Dounousi, Evangelia / Petrou, Anastasios / Tselepis, Alexandros D

Medical principles and practice : international journal of the Kuwait University, Health Science Centre

2023

Abstract: Background: Severe variations in osmotic pressure are significant contributors to critical patient morbidity and mortality and might also affect platelet volume. We aimed to investigate possible osmotic-induced changes in mean platelet volume (MPV) and ... ...

Abstract	Background: Severe variations in osmotic pressure are significant contributors to critical patient morbidity and mortality and might also affect platelet volume. We aimed to investigate possible osmotic-induced changes in mean platelet volume (MPV) and their possible effects on platelet aggregation activity (PLAG). Methods: We induced experimental variations of serum osmolality in blood samples from healthy volunteers (heparinized whole blood, WB) and isolated platelets (Platelet Rich Plasma, PRP) by adding isotonic, hypertonic, and hypotonic solutions of saline/water (pH = 7.2-7.4). PLAG was tested in WB samples with Impedance Aggregometry (IA) and in PRP samples with Light Transmission Aggregometry (LTA) using three agonists Adenosine Diphosphate (ADP, 10 μΜ), Thrombin Receptor Activating Peptide (TRAP-6, 10 μΜ) and Arachidonic Acid (AA, 500 μΜ). Osmolality was either calculated using a formula or measured directly. Results: We found almost identical osmolalities in WB and PRP preparations. Osmotic stress did not produce significant changes in MPV. In IA testing the hypotonic challenge of WB preparations produced significant reductions at 50 % (p = 0.056) (95 % CI: 11.2-2.4, in Ohms) of ADP and at 31 % (p = 0.017) (95 % CI: 13.4-8.6, in Ohms) of TRAP-6 -induced PLAG respectively. In PRP we did not observe any variations in PLAG with LTA. Conclusions: We conclude that in vitro hypotonic stress of WB samples has an inhibitory effect on the PAR-1 (TRAP-6 induced) pathway and on the P2Y12 (ADP induced) pathway and reflects a distinct in vivo effect of hypo-osmotic stress on WB human platelet preparations.
Language	English
Publishing date	2023-09-13
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	645108-1
ISSN	1423-0151 ; 1011-7571
ISSN (online)	1423-0151
ISSN	1011-7571
DOI	10.1159/000533852
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Article ; Online: The impact of right ventricular hemodynamics on the performance of a left ventricular assist device in a numerical simulation model.

Thut, Titus L Z / Petrou, Anastasios / Meboldt, Mirko / Daners, Marianne Schmid / Wilhelm, Markus J

Biomedizinische Technik. Biomedical engineering

2023 Volume 68, Issue 5, Page(s) 503–510

Abstract: Objectives: Left ventricular assist devices (LVADs) have been established as alternative to heart transplantation for patients with end-stage heart failure refractory to medical therapy. Right heart failure (RHF) after LVAD implantation is associated ... ...

Abstract	Objectives: Left ventricular assist devices (LVADs) have been established as alternative to heart transplantation for patients with end-stage heart failure refractory to medical therapy. Right heart failure (RHF) after LVAD implantation is associated with inferior outcome. Its preoperative anticipation may influence the selection between a pure left ventricular and a biventricular device type and, thus, improve outcomes. Reliable algorithms to predict RHF are missing. Methods: A numerical model was used for simulation of a cardiovascular circulation. The LVAD was placed as parallel circuit between left ventricle and aorta. In contrast to other studies, the dynamic hydraulic behavior of a pulsatile LVAD was replaced by that of a continuous LVAD. A variety of hemodynamic states was tested mimicking different right heart conditions. Adjustable parameters included heart rate (HR), pulmonary vascular resistance (PVR), tricuspid regurgitation (TR), right ventricular contractility (RVC) and pump speed. Outcome parameters comprised central venous pressure (CVP), mean pulmonary artery pressure (mPAP), cardiac output (CO) and occurrence of suction. Results: Alteration of HR, PVR, TR, RVC and pump speed resulted in diverse effects on CO, CVP and mPAP, resulting in improvement, impairment or no change of the circulation, depending on the degree of alteration. Conclusions: The numerical simulation model allows prediction of circulatory changes and LVAD behaviour following variation of hemodynamic parameters. Such a prediction may be of particular advantage to anticipate RHF after LVAD implantation. It may help preoperatively to choose the appropriate strategy of only left ventricular or both left and right ventricular support.
MeSH term(s)	Humans ; Heart Ventricles ; Heart-Assist Devices ; Hemodynamics ; Heart Failure/therapy ; Heart Transplantation ; Retrospective Studies ; Ventricular Dysfunction, Right/complications ; Ventricular Dysfunction, Right/therapy
Language	English
Publishing date	2023-04-27
Publishing country	Germany
Document type	Journal Article
ZDB-ID	120817-2
ISSN	1862-278X ; 0013-5585
ISSN (online)	1862-278X
ISSN	0013-5585
DOI	10.1515/bmt-2020-0188
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Article: The Effect of Cell Salvage on Bleeding and Transfusion Needs in Cardiac Surgery.

Tachias, Frixos / Samara, Evangelia / Petrou, Anastasios / Karakosta, Agathi / Siminelakis, Stavros / Apostolakis, Efstratios / Tzimas, Petros

Anesthesiology research and practice

2022 Volume 2022, Page(s) 3993452

Abstract: Introduction: Cell salvaging is well established in the blood management of cardiac patients, but there remain some concerns about its effects on perioperative bleeding and transfusion variables. This randomized controlled study investigated the ... ...

Abstract	Introduction: Cell salvaging is well established in the blood management of cardiac patients, but there remain some concerns about its effects on perioperative bleeding and transfusion variables. This randomized controlled study investigated the potential effects of the centrifuged end-product on bleeding, transfusion rates, and other transfusion-related variables in adult cardiac surgery patients submitted to extracorporeal circulation. Materials and methods: Patients were randomly chosen to receive (cell-salvage group, 99 patients) or not to receive (control group, 110 patients) the centrifuged product of a cell salvage apparatus. Bleeding and transfusion rates according to the universal definition of perioperative bleeding (UDPB) classification, postoperative hemoglobin, coagulation, and oxygenation indices were recorded and compared between the groups. Results: Both groups had almost identical bleeding and transfusion rates (median value: 2 units of red blood cells (RBC) and no units of fresh frozen plasma (FFP) and platelets (PLT) for both groups, Conclusion: Within the study's constraints, the perioperative use of the cell salvage concentrate does not seem to affect bleeding or transfusion variables, although it could probably ameliorate postoperative oxygenation in adult cardiac surgery patients. A tendency to promote coagulation disturbances was detected.
Language	English
Publishing date	2022-09-01
Publishing country	United States
Document type	Journal Article
ZDB-ID	2397574-X
ISSN	1687-6970 ; 1687-6962
ISSN (online)	1687-6970
ISSN	1687-6962
DOI	10.1155/2022/3993452
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Article ; Online: Cardiac Output Estimation: Online Implementation for Left Ventricular Assist Device Support.

Petrou, Anastasios / Kanakis, Menelaos / Magkoutas, Konstantinos / de Vries, Bob / Meboldt, Mirko / Daners, Marianne Schmid

IEEE transactions on bio-medical engineering

2021 Volume 68, Issue 6, Page(s) 1990–1998

Abstract: Objective: We present a novel pipeline that consists of various algorithms for the estimation of the cardiac output (CO) during ventricular assist devices (VADs) support using a single pump inlet pressure (PIP) sensor as well as pump intrinsic signals.!# ...

Abstract	Objective: We present a novel pipeline that consists of various algorithms for the estimation of the cardiac output (CO) during ventricular assist devices (VADs) support using a single pump inlet pressure (PIP) sensor as well as pump intrinsic signals. Methods: A machine learning (ML) model was constructed for the prediction of the aortic valve opening status. When a closed aortic valve is detected, the estimated CO equals the estimated pump flow. Otherwise, the estimated CO equals the sum of the estimated pump flow and the aortic valve flow, estimated via a Kalman-filter approach. Both the pathophysiological conditions and the pump speed of an in-vitro test bench were adjusted in various combinations to evaluate the performance of the pipeline, as well as the individual estimators. Results: The ML model yielded a Matthews correlation coefficient of 0.771, a sensitivity of 0.913 and a specificity of 0.871. An overall CO root mean square error (RMSE) of 0.69 L/min was achieved. Replacing the pump flow and aortic pressure estimators with sensors would decrease the RMSE below 0.5 L/min. Conclusion: The performance of the proposed pipeline is considered the state of the art for VADs with an integrated PIP sensor. The effect of the individual estimators on the overall performance of the pipeline was thoroughly investigated and their limitations were identified for future research. Significance: The clinical application of the proposed solution could provide the clinicians with essential information about the interaction between the patient's heart and the VAD to further improve the VAD therapy.
MeSH term(s)	Algorithms ; Aortic Valve/surgery ; Cardiac Output ; Heart-Assist Devices ; Hemodynamics ; Humans
Language	English
Publishing date	2021-05-21
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	160429-6
ISSN	1558-2531 ; 0018-9294
ISSN (online)	1558-2531
ISSN	0018-9294
DOI	10.1109/TBME.2020.3045879
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Article ; Online: A Versatile Hybrid Mock Circulation for Hydraulic Investigations of Active and Passive Cardiovascular Implants.

Petrou, Anastasios / Granegger, Marcus / Meboldt, Mirko / Schmid Daners, Marianne

ASAIO journal (American Society for Artificial Internal Organs : 1992)

2018 Volume 65, Issue 5, Page(s) 495–502

Abstract: During the development process of active or passive cardiovascular implants, such as ventricular assist devices or vascular grafts, extensive in-vitro testing is required. The aim of the study was to develop a versatile hybrid mock circulation (HMC) ... ...

Abstract	During the development process of active or passive cardiovascular implants, such as ventricular assist devices or vascular grafts, extensive in-vitro testing is required. The aim of the study was to develop a versatile hybrid mock circulation (HMC) which can support the development of such implants that have a complex interaction with the circulation. The HMC operates based on the hardware-in-the-loop concept with a hydraulic interface of four pressure-controlled reservoirs allowing the interaction of the implant with a numerical model of the cardiovascular system. Three different conditions were investigated to highlight the versatility and the efficacy of the HMC during the development of such implants: 1) biventricular assist device (BiVAD) support with progressive aortic valve insufficiency, 2) total artificial heart (TAH) support with increasing pulmonary vascular resistance, and 3) flow distribution in a total cavopulmonary connection (TCPC) in a Fontan circulation during exercise. Realistic pathophysiologic waveforms were generated with the HMC and all hemodynamic conditions were simulated just by adapting the software. The results of the experiments indicated the potential of physiologic control during BiVAD or TAH support to prevent suction or congestion events, which may occur during constant-speed operation. The TCPC geometry influenced the flow distribution between the right and the left pulmonary artery, which was 10% higher in the latter and led to higher pressures. Together with rapid prototyping methods, the HMC may enhance the design of implants to achieve better hemodynamics. Validation of the models with clinical recordings is suggested for increasing the reliability of the HMC.
MeSH term(s)	Computer Simulation ; Heart-Assist Devices ; Hemodynamics/physiology ; Humans ; Models, Cardiovascular ; Reproducibility of Results ; Vascular Grafting
Language	English
Publishing date	2018-07-24
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	759982-1
ISSN	1538-943X ; 0162-1432 ; 1058-2916
ISSN (online)	1538-943X
ISSN	0162-1432 ; 1058-2916
DOI	10.1097/MAT.0000000000000851
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Article ; Online: Correction to: Comparison of Flow Estimators for Rotary Blood Pumps: An In Vitro and In Vivo Study.

Petrou, Anastasios / Kuster, Daniel / Lee, Jongseok / Meboldt, Mirko / Schmid Daners, Marianne

Annals of biomedical engineering

2019 Volume 47, Issue 8, Page(s) 1827

Abstract: This erratum is to correct the third row of Table 2, where parameter ... ...

Abstract	This erratum is to correct the third row of Table 2, where parameter h
Language	English
Publishing date	2019-05-30
Publishing country	United States
Document type	Journal Article ; Published Erratum
ZDB-ID	185984-5
ISSN	1573-9686 ; 0191-5649 ; 0090-6964
ISSN (online)	1573-9686
ISSN	0191-5649 ; 0090-6964
DOI	10.1007/s10439-019-02295-0
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Article ; Online: A Novel Multi-objective Physiological Control System for Rotary Left Ventricular Assist Devices.

Petrou, Anastasios / Monn, Marcial / Meboldt, Mirko / Schmid Daners, Marianne

Annals of biomedical engineering

2017 Volume 45, Issue 12, Page(s) 2899–2910

Abstract: Various control and monitoring algorithms have been proposed to improve the left-ventricular assist device (LVAD) therapy by reducing the still-occurring adverse events. We developed a novel multi-objective physiological control system that relies on the ...

Abstract	Various control and monitoring algorithms have been proposed to improve the left-ventricular assist device (LVAD) therapy by reducing the still-occurring adverse events. We developed a novel multi-objective physiological control system that relies on the pump inlet pressure (PIP). Signal-processing algorithms have been implemented to extract the required features from the PIP. These features then serve for meeting various objectives: pump flow adaptation to the perfusion requirements, aortic valve opening for a predefined time, augmentation of the aortic pulse pressure, and monitoring of the LV pre- and afterload conditions as well as the cardiac rhythm. Controllers were also implemented to ensure a safe operation and prevent LV suction, overload, and pump backflow. The performance of the control system was evaluated in vitro, under preload, afterload and contractility variations. The pump flow adapted in a physiological manner, following the preload changes, while the aortic pulse pressure yielded a threefold increase compared to a constant-speed operation. The status of the aortic valve was detected with an overall accuracy of 86% and was controlled as desired. The proposed system showed its potential for a safe physiological response to varying perfusion requirements that reduces the risk of myocardial atrophy and offers important hemodynamic indices for patient monitoring during LVAD therapy.
Language	English
Publishing date	2017-12
Publishing country	United States
Document type	Journal Article
ZDB-ID	185984-5
ISSN	1573-9686 ; 0191-5649 ; 0090-6964
ISSN (online)	1573-9686
ISSN	0191-5649 ; 0090-6964
DOI	10.1007/s10439-017-1919-0
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Article ; Online: Auricular Acupuncture Analgesia in Thoracic Trauma: A Case Report.

Papadopoulos, Georgios S / Tzimas, Petros / Liarmakopoulou, Antonia / Petrou, Anastasios M

Journal of acupuncture and meridian studies

2017 Volume 10, Issue 1, Page(s) 49–52

Abstract: We report a case of thoracic trauma (rib fractures with pneumothorax and pulmonary contusions) with severe chest pain leading to ineffective ventilation and oxygenation. The patient presented to our emergency department. The patient had chronic ... ...

Abstract	We report a case of thoracic trauma (rib fractures with pneumothorax and pulmonary contusions) with severe chest pain leading to ineffective ventilation and oxygenation. The patient presented to our emergency department. The patient had chronic obstructive pulmonary disease and was completely unable to take deep breaths and clear secretions from his bronchial tree. After obtaining informed consent, we applied auricular acupuncture to ameliorate pain and hopefully improve his functional ability to cough and breathe deeply. Within a few minutes, his pain scores diminished considerably, and his ventilation and oxygenation indices improved to safe limits. Auricular acupuncture analgesia lasted for several hours. Parallel to pain reduction, hemodynamic disturbances and anxiety significantly resolved. A second treatment nearly a day later resulted in almost complete resolution of pain that lasted at least 5 days and permitted adequate ventilation, restored oxygenation, and some degree of mobilization (although restricted due to a compression fracture of a lumbar vertebra). Nonopioid and opioid analgesics were sparsely used in low doses during the entire hospitalization period. Hemodynamic alterations and anxiety also decreased, and the patient was soon ready to be discharged.
MeSH term(s)	Acupuncture Analgesia ; Acupuncture, Ear ; Humans ; Male ; Middle Aged ; Pain Management ; Rib Fractures/physiopathology ; Thoracic Injuries/physiopathology
Language	English
Publishing date	2017-01
Publishing country	Korea (South)
Document type	Case Reports ; Journal Article
ISSN	2093-8152
ISSN (online)	2093-8152
DOI	10.1016/j.jams.2016.06.003
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Article ; Online: Comparison of Flow Estimators for Rotary Blood Pumps: An In Vitro and In Vivo Study.

Petrou, Anastasios / Kuster, Daniel / Lee, Jongseok / Meboldt, Mirko / Schmid Daners, Marianne

Annals of biomedical engineering

2018 Volume 46, Issue 12, Page(s) 2123–2134

Abstract: Various approaches for estimating the flow rate of a rotary blood pump have been proposed for monitoring and control purposes. They have been evaluated under different test conditions and, therefore, a direct comparison among them is difficult. ... ...

Abstract	Various approaches for estimating the flow rate of a rotary blood pump have been proposed for monitoring and control purposes. They have been evaluated under different test conditions and, therefore, a direct comparison among them is difficult. Furthermore, a limited performance has been reported for the areas where the pump flow and motor current present a non-monotonic relationship. In this regard, we selected most approaches that have been presented in literature and added a modified one, resulting in four estimators, which are either non-invasive or invasive, i.e., inlet and outlet pump pressure sensors are used. Data from in vitro and in vivo studies with the Deltastream pump DP2 were used to compare the estimators under the same test conditions. These data included both constant and varying pre- and afterload, contractility, viscosity, as well as pump speed settings. Bland-Altman plots were used to evaluate the performance of the estimators. The mean error of the overall estimated flow in vitro ranged from 0.002 to 0.38 L/min and the limits of agreement (LoA) between ± 2 L/min. During negative flows the mean error decreased by about 25% when the pump inlet pressure was added as an input. In vivo, the mean errors increased, while the LoA remained in the same range. An estimator based on pump pressure difference improves the reliability in areas where flow and current relationship is not monotonic. A trade-off between estimation accuracy and number of sensors was identified. The estimation objective and the potential errors should be considered when selecting an estimation approach and designing the pump systems.
MeSH term(s)	Animals ; Blood Circulation ; Heart-Assist Devices ; Humans ; Models, Cardiovascular ; Swine
Language	English
Publishing date	2018-07-27
Publishing country	United States
Document type	Comparative Study ; Journal Article
ZDB-ID	185984-5
ISSN	1573-9686 ; 0191-5649 ; 0090-6964
ISSN (online)	1573-9686
ISSN	0191-5649 ; 0090-6964
DOI	10.1007/s10439-018-2106-7
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