Implementing the Sano Modification in an Experimental Model of the Norwood Circulation

2012 ◽  
Author(s):  
Giovanni Biglino ◽  
Alessandro Giardini ◽  
Catriona Baker ◽  
Tain-Yen Hsia ◽  
Richard S. Figliola ◽  
...  
Keyword(s):  
Right Ventricle ◽  
Experimental Model ◽  
Circulatory System ◽  
Systemic Circulation ◽  
Norwood Procedure ◽  
Patient Specific ◽  
Surgical Approaches ◽  
Mock Circulatory System ◽  
Stage 1

Surgical palliation of hypoplastic left heart syndrome (HLHS) is performed in three stages, the first of which is known as the Norwood procedure [1]. Traditionally, this operation involves securing an unobstructed outlet for the systemic circulation in infants for whom the single right ventricle is the only pump in the system, with pulmonary flow sourced via a modified Blalock-Taussig (BT) shunt. In 2003, Sano et al. have proposed a radical variation of this operation, known as the Sano modification [2]. In this case, the pulmonary circulation is supplied directly from the systemic right ventricle via an unvalved ventriculo-pulmonary Goretex conduit, or Sano shunt. Characteristically, flow in the Sano shunt continues throughout diastole (diastolic runoff). Differences between surgical approaches for stage 1 palliation have been addressed in the literature [3]. A computational model of Norwood procedure and Sano modification has also been proposed [4]. However, an experimental model of this complex physiology is currently lacking. Having recently presented an in vitro model of stage 1 physiology with a BT shunt arrangement [5], we propose here a compact mock circulatory system suitable for simulating the Sano physiology in patient-specific anatomical models.

Designing a Patient-Specific Paediatric Mock Circulatory System to Study the Norwood Circulation

2011 ◽  
Author(s):  
Giovanni Biglino ◽  
Silvia Schievano ◽  
Catriona Baker ◽  
Alessandro Giardini ◽  
Richard Figliola ◽  
...  
Keyword(s):  
Ductus Arteriosus ◽  
Pulmonary Arteries ◽  
Circulatory System ◽  
Innominate Artery ◽  
Systemic Circulation ◽  
Norwood Procedure ◽  
Patient Specific ◽  
Mock Circulatory System ◽  
Pulmonary Flow ◽  
Left Heart Syndrome

The Stage I of Fontan palliation for neonates with hypoplastic left heart syndrome, namely the Norwood procedure, aims to improve the flow of oxygenated blood in the systemic circulation while at the same time providing blood flow to the pulmonary circulation1. This surgical operation usually involves enlargement of the hypoplastic aorta by means of a patch, reconstruction of aortic coarctation and increase pulmonary flow. The latter point, at present, is achieved in three different ways: i) a Blalock-Taussig (BT) shunt from the innominate artery to the pulmonary artery, ii) an atrio-pulmonary shunt, referred to as Sano modification2 and iii) stenting the ductus arteriosus and banding the pulmonary arteries, referred to as “hybrid” Norwood3. In general, it is clear that the circulation following the Norwood procedure presents a very specific and complex arrangement.

scholarly journals A reinforced right-ventricle-to-pulmonary-artery conduit for the stage-1 Norwood procedure improves pulmonary artery growth

2015 ◽  
Vol 149 (6) ◽  
pp. 1502-1508.e1 ◽  
Author(s):  
James R. Bentham ◽  
Christopher W. Baird ◽  
Deigo P. Porras ◽  
Rahul H. Rathod ◽  
Audrey C. Marshall
Keyword(s):  
Pulmonary Artery ◽  
Right Ventricle ◽  
Norwood Procedure ◽  
Stage 1 ◽  
Artery Conduit

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.

Body-on-a chip: Using microfluidic systems to predict human responses to drugs

2010 ◽  
Vol 82 (8) ◽  
pp. 1635-1645 ◽  
Author(s):  
Michael L. Shuler ◽  
Mandy B. Esch
Keyword(s):  
Cell Culture ◽  
Human Body ◽  
Mammalian Cells ◽  
Circulatory System ◽  
Systemic Circulation ◽  
Multidrug Resistant ◽  
Toxicological Studies ◽  
In Vitro Systems ◽  
Barrier Tissues

Using an in vitro platform technology that combines microfabricated devices with cell culture, we seek to understand the response of the human body to pharmaceuticals and combinations of pharmaceuticals. Computer models of the human body guide the design of in vitro systems we call micro cell culture analogs (μCCAs) or “body-on-a-chip” devices. A μCCA device is a physical representation of a physiologically based pharmacokinetic (PBPK) model and contains mammalian cells cultured in interconnected microchambers to represent key organs linked through a circulatory system. μCCAs can provide inexpensive means for realistic, accurate, and rapid-throughput toxicological studies that do not require experimenting with animals and reveal toxic effects that can result from interactions between organs. As the natural length scale in biological systems is on the order of 10–100 μm, operating on the microscale allows us to mimic physiological relationships more accurately. We summarize proof-of-concept experiments using mixtures of drugs to treat multidrug-resistant (MDR) cancer and colon cancer. We discuss the extension of the μCCA concept to systems that connect barrier tissues with systemic circulation. Examples with models of the gastro-intestinal (GI) tract are provided.

A microfluidic circulatory system integrated with capillary-assisted pressure sensors

Lab on a Chip ◽  
2017 ◽  
Vol 17 (4) ◽  
pp. 653-662 ◽  
Author(s):  
Yangfan Chen ◽  
Ho Nam Chan ◽  
Sean A. Michael ◽  
Yusheng Shen ◽  
Yin Chen ◽  
...  
Keyword(s):  
Pressure Sensors ◽  
Circulatory System ◽  
Systemic Circulation

We present a microfluidic circulatory system integrated with capillary-assisted pressure sensors to closely mimic human systemic circulation in vitro.

scholarly journals Effective Computational Framework for Pre-Interventional Planning of Peripheral Arteriovenous Malformations with In Vivo and In Vitro Validation

2021 ◽  
Author(s):  
Gaia Franzetti ◽  
Mirko Bonfanti ◽  
Cyrus Tanade ◽  
Chung Sim Lim ◽  
Janice Tsui ◽  
...  
Keyword(s):  
Blood Flow ◽  
Computational Model ◽  
Arteriovenous Malformations ◽  
Clinical Decision Making ◽  
Patient Specific ◽  
Post Intervention ◽  
Computational Framework ◽  
Mock Circulatory System ◽  
Flow Through

Purpose: Peripheral arteriovenous malformations (pAVMs) are congenital lesions characterised by abnormal high-flow, low-resistance vascular connections - constituting the so-called nidus - between arteries and veins. The mainstay treatment typically involves the embolisation of the nidus with embolic and sclerosant agents, however the complexity of AVMs often leads to uncertain outcomes. This study aims at developing a simple, yet effective computational framework to aid the clinical decision making around the treatment of pAVMs. Methods: A computational model was developed to simulate the pre-, intra-, and post-intervention haemodynamics of an AVM. A porous medium of varying permeability was used to simulate the effect that the sclerosant has on the blood flow through the nidus. The computational model was informed by computed tomography (CT) scans and digital subtraction angiography (DSA) images, and the results were compared against clinical data and experimental results. Results: The computational model was able to simulate the blood flow through the AVM throughout the intervention and predict (direct and indirect) haemodynamic changes due to the embolisation. The simulated transport of the dye in the AVM was compared against DSA time-series obtained at different intervention stages, providing confidence in the results. Moreover, experimental data obtained via a mock circulatory system involving a patient specific 3D printed phantom of the same AVM provided further validation of the simulation results. Conclusion: We developed a simple computational framework to simulate AVM haemodynamics and predict the effects of the embolisation procedure. The developed model lays the foundation of a new, computationally driven treatment planning tool for AVM embolisation procedures.

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