In-vitro investigation of pathophysiologic responses to exercise conditions in single ventricular patients
Abstract
Around 8% of all newborns with a congenital heart defect have only a single functioning ventricle (SV). The Fontan circulation is a result of the third stage surgical procedure to correct the SV anatomy in these patients. Despite successful implementation over the years, this altered circulation is prone to failure, with survival rates of only 50-80% to adulthood. Increased inferior vena caval (IVC) pressure plays a significant role in "Fontan failure." A rapidly testable novel alternative is proposed by creating an Injection Jet Shunt (IJS) drawing flow directly from the aortic arch, balanced by a conduit-to-atrial fenestration to approximately preserve the ratio of pulmonary flow (Qp) to systemic flow (Qs). The main concept involves the injection of a high-velocity jet in the direction of inferior vena cava (IVC) flow, causing flow entrainment, leading to a significant reduction of upstream (i.e., IVC) pressure and enhancement of downstream flow. A dynamically scaled benchtop Mock Flow Loop (MFL) is configured to validate this hypothesis. Three IJS nozzles of varying diameters (i.e., 2mm, 3mm and 4mm) implanted in different types of total cavopulmonary connection (TCPC) phantoms (namely 2Y, and Torus) are tested to validate the hypothesis and achieve the maximum caval pressure reduction. The MFL replicates a reduced four-compartmental lumped parameter model of the Fontan circulation, and it is integrated with a patient generic 3D phantom of the IJS-assisted Fontan with average dimensions matching those of a 2–4-year-old patient. Experimental results are presented and compared to the computational findings on the hemodynamic results and oxygen saturations for various IJS assisted Fontan configurations.
Keywords: congenital heart defect; particle image velocimetry, machine learning, mock flow loop, in-vitro,
In-vitro investigation of pathophysiologic responses to exercise conditions in single ventricular patients
Around 8% of all newborns with a congenital heart defect have only a single functioning ventricle (SV). The Fontan circulation is a result of the third stage surgical procedure to correct the SV anatomy in these patients. Despite successful implementation over the years, this altered circulation is prone to failure, with survival rates of only 50-80% to adulthood. Increased inferior vena caval (IVC) pressure plays a significant role in "Fontan failure." A rapidly testable novel alternative is proposed by creating an Injection Jet Shunt (IJS) drawing flow directly from the aortic arch, balanced by a conduit-to-atrial fenestration to approximately preserve the ratio of pulmonary flow (Qp) to systemic flow (Qs). The main concept involves the injection of a high-velocity jet in the direction of inferior vena cava (IVC) flow, causing flow entrainment, leading to a significant reduction of upstream (i.e., IVC) pressure and enhancement of downstream flow. A dynamically scaled benchtop Mock Flow Loop (MFL) is configured to validate this hypothesis. Three IJS nozzles of varying diameters (i.e., 2mm, 3mm and 4mm) implanted in different types of total cavopulmonary connection (TCPC) phantoms (namely 2Y, and Torus) are tested to validate the hypothesis and achieve the maximum caval pressure reduction. The MFL replicates a reduced four-compartmental lumped parameter model of the Fontan circulation, and it is integrated with a patient generic 3D phantom of the IJS-assisted Fontan with average dimensions matching those of a 2–4-year-old patient. Experimental results are presented and compared to the computational findings on the hemodynamic results and oxygen saturations for various IJS assisted Fontan configurations.
Keywords: congenital heart defect; particle image velocimetry, machine learning, mock flow loop, in-vitro,