Hemodynamic Effect of a Fontan Assist Device on a Numerical Fontan Circulatory Model under Various Medication Scenarios.

Patients with single-ventricle heart disease and failing Fontan circulation represent the largest and most rapidly growing subgroup of adults with congenital heart disease referred for transplant assessment. Few clinical therapies are available for improving Fontan hemodynamics. Mechanical circulatory support devices have been used successfully in the clinical setting to assist the single ventricle, but no device is currently available to support the subpulmonary circulation. A subpulmonary pump could be used to support patients with failing Fontan circulation by mitigating chronic venous hypertension and restoring normal physiology. Our group designed a Fontan assist device (FAD) to augment right-heart (subpulmonary) flow and decrease venous pressures. To ensure that our FAD could achieve target hemodynamic parameters, we developed a numerical Fontan circulatory model to evaluate the interaction between the cardiovascular system and the FAD. To ensure that the circulatory model can mimic real-world clinical conditions, we investigated the effects of various medications in the FAD loop. Results showed that the FAD can significantly increase cardiac output in Fontan patients and can create a pressure difference between the pulmonary arteries and venae cavae. Further, the systemic venous pressure can be significantly reduced by using the FAD plus diuretic treatment. The downstream pulmonary artery pressure can be increased by augmenting the FAD with vasodilator treatment, diuretic treatment, or both.Clinical Relevance- This work supports FAD development by providing a method for studying human cardiovascular effects under various hemodynamic scenarios.

3D-Printed silicone anatomic patient simulator to enhance training on cardiopulmonary bypass.

BACKGROUND: Simulator training is important for teaching perfusion students fundamental skills associated with CBP before they start working in the clinic. Currently available high-fidelity simulators lack anatomic features that would help students visually understand the connection between hemodynamic parameters and anatomic structure. Therefore, a 3D-printed silicone cardiovascular system was developed at our institution. This study aimed to determine whether using this anatomic perfusion simulator instead of a traditional "bucket" simulator would better improve perfusion students' understanding of cannulation sites, blood flow, and anatomy. METHODS: Sixteen students were tested to establish their baseline knowledge. They were randomly divided into two groups to witness a simulated bypass pump run on one of two simulators - anatomic or bucket - then retested. To better analyze the data, we defined "true learning" as characterized by an incorrect answer on the pre-simulation assessment being corrected on the post-simulation assessment. RESULTS: The group that witnessed the simulated pump run on the anatomic simulator showed a larger increase in mean test score, more instances of true learning, and a larger gain in the acuity confidence interval. CONCLUSIONS: Despite the small sample size, the results suggest that the anatomic simulator is a valuable instrument for teaching new perfusion students.

Physiological Control Algorithm for a Pulsatile-flow 3D Printed Circulatory Model to Simulate Human Cardiovascular System.

The human heart is responsible for maintaining constant, pulsatile blood flow in the human body. Mock circulatory loops (MCLs) have long been used as the mechanical representations of the human cardiovascular system and as test beds for mechanical circulatory support (MCS) devices and other interventional medical devices. This technology could also be used as a training and educational tool for surgeons/clinicians. To ensure the MCL can accurately simulate the pulsatile human cardiovascular system, it is essential that the MCL can reproduce human physiological responses, e.g., the Frank-Starling Mechanism, in a controllable operating environment. In this study, by using an elastance function template to control the simulated left ventricle, we created controllable pulsatile physiological flow in a 3D printed silicone vascular structure to successfully simulate the hemodynamic environment of the human cardiovascular system. Clinical Relevance- This work will provide an in vitro test platform to simulate the human cardiovascular system. The accurate simulation of human cardiovascular anatomy and hemodynamic environment will allow this device to be an ideal training/educational tool for surgeons/clinicians to recreate various physiological conditions that cannot be created in vivo in animal or cadaver models.