Hybrid Mock Circulatory System to Test Cardiovascular Prostheses on the Grid

2011 ◽  
pp. 410-424
Author(s):  
Francesco Maria Colacino ◽  
Maurizio Arabia ◽  
Gionata Fragomeni
Keyword(s):  
Cardiovascular System ◽  
New Technologies ◽  
Circulatory System ◽  
In Vitro Experiments ◽  
Cardiovascular Devices ◽  
Mock Circulatory System ◽  
Time Interaction ◽  
Passive Devices ◽  
Remote Experimentation

In the last decades cardiovascular diseases greatly increased worldwide, and bioengineering provided new technologies and cardiovascular prostheses to medical doctors and surgeons. The design of active and passive devices aroused notable interests becoming more and more challenging as well as crucial. In this framework, it is important to faithfully reproduce the interaction between the prostheses and the cardiovascular system when in-vitro experiments are performed. For this reason, a new and improved kind of test benches becomes necessary. Purely hydraulic mock circulatory systems showed low flexibility to allow tests of different cardiovascular devices and low precision when a reference mathematical model must be reproduced. In this chapter a new bench is described. It combines the computer model of the cardiovascular system and its real-time interaction with the device to be tested. The solution adopted can be exploited in a Grid environment to allow remote experimentation.

scholarly journals In vitro study of trileaflet polytetrafluoroethylene conduit and its valve-in-valve transformation

2020 ◽  
Vol 30 (3) ◽  
pp. 408-416 ◽  
Author(s):  
Te-I Chang ◽  
Kang-Hong Hsu ◽  
Chi-Wen Luo ◽  
Jen-Hong Yen ◽  
Po-Chien Lu ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Stent Graft ◽  
Peak Pressure ◽  
Circulatory System ◽  
Valve Design ◽  
Mock Circulatory System ◽  
Valved Conduit ◽  
Valve In Valve ◽  
In Vitro Performance

Abstract OBJECTIVES Handmade trileaflet expanded polytetrafluoroethylene valved conduit developed using the flip-over method has been tailored for pulmonary valve reconstruction with satisfactory outcomes. We investigated the in vitro performance of the valve design in a mock circulatory system with various conduit sizes. In our study, the design was transformed into a transcatheter stent graft system which could fit in original valved conduits in a valve-in-valve fashion. METHODS Five different sizes of valved polytetrafluoroethylene vascular grafts (16, 18, 20, 22 and 24 mm) were mounted onto a mock circulatory system with a prism window for direct leaflets motion observation. Transvalvular pressure gradients were recorded using pressure transducers. Mean and instant flows were determined via a rotameter and a flowmeter. Similar flip-over trileaflet valve design was then carried out in 3 available stent graft sizes (23, 26 and 28.5 mm, Gore aortic extender), which were deployed inside the valved conduits. RESULTS Peak pressure gradient across 5 different sized graft valves, in their appropriate flow setting (2.0, 2.5 and 5.0 l/min), ranged from 4.7 to 13.2 mmHg. No significant valve regurgitation was noted (regurgitant fraction: 1.6–4.9%) in all valve sizes and combinations. Three sizes of the trileaflet-valved stent grafts were implanted in the 4 sizes of valved conduits except for the 16-mm conduit. Peak pressure gradient increase after valved-stent graft-in-valved-conduit setting was <10 mmHg in all 4 conduits. CONCLUSIONS The study showed excellent in vitro performance of trileaflet polytetrafluoroethylene valved conduits. Its valved stent graft transformation provided data which may serve as a reference for transcatheter valve-in-valve research in the future.

Validation of Cardiac Output as Reported by a Permanently Implanted Wireless Sensor

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Michael Tree ◽  
Jason White ◽  
Prem Midha ◽  
Samantha Kiblinger ◽  
Ajit Yoganathan
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Measurement Accuracy ◽  
Circulatory System ◽  
Left Heart Failure ◽  
Mock Circulatory System ◽  
System A ◽  
Reference Flow ◽  
Relevant Range

The CardioMEMS heart failure (HF) system was tested for cardiac output (CO) measurement accuracy using an in vitro mock circulatory system. A software algorithm calculates CO based on analysis of the pressure waveform as measured from the pulmonary artery, where the CardioMEMS system resides. Calculated CO was compared to that from reference flow probe in the circulatory system model. CO measurements were compared over a clinically relevant range of stroke volumes and heart rates with normal, pulmonary hypertension (PH), decompensated left heart failure (DLHF), and combined DHLF + PH hemodynamic conditions. The CardioMEMS CO exhibited minimal fixed and proportional bias.

In Vitro Study of Flow Regulation for Pulmonary Insufficiency Using Diode Valves

2007 ◽  
Author(s):  
Tiffany A. Camp ◽  
Stephanie Hequembourg ◽  
Richard S. Figliola ◽  
Tim McQuinn
Keyword(s):  
Pulmonary Valve ◽  
Pulmonary Regurgitation ◽  
Circulatory System ◽  
In Vitro Study ◽  
Pulmonary Insufficiency ◽  
Pressure Gradients ◽  
Right Heart ◽  
Mock Circulatory System ◽  
The Right

The operating pressures in the right heart are significantly lower than those of the left heart and with marked differences in the circulation impedances. The pulmonary circulation shows a tolerance for mild regurgitation and pressure gradient [1]. Pulmonary regurgitation fractions on the order of 20% and transvalvular pressure gradients of less than 25mm Hg are considered mild [4]. Given this tolerance, we examine the concept of using a motionless valve to regulate flow in the pulmonary position. In a previous study, the use of fluid diodes was shown to be a promising concept for use as a pulmonary valve [2]. In this study, we test two different diode designs. For each diode valve, flow performance was documented as a function of pulmonary vascular resistance (PVR) and compliance. Tests were done using a pulmonary mock circulatory system [3] over the normal adult range of PVR and compliance settings.

The Cardiovascular Microenvironment

2007 ◽  
Author(s):  
Cynthia A. Reinhart-King ◽  
Keigi Fujiwara ◽  
Michael R. King
Keyword(s):  
Shear Stress ◽  
Endothelial Cell ◽  
Cardiovascular System ◽  
Cell Response ◽  
Circulatory System ◽  
Length Scale ◽  
Mechanical Signal ◽  
Endothelial Cell Response

Endothelial cell response to the complex hemodynamic environment of the circulatory system is critical to the pathophysiological regulation of the cardiovascular system; however the mechanism by which this mechanical signal is transduced remains poorly understood. Recent in vivo evidence suggests that cells are capable of responding locally to shear stress, on the length scale of a single cell. Because of the complexity of the in vivo environment, we have designed and characterized an in vitro microchannel chamber with well-defined rheological conditions. This system is being used to investigate endothelial cell signaling response to shear stress, thereby bridging the gap between in vivo and in vitro observations.

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