In Vitro Assessment of the Assisted Bidirectional Glenn Procedure for Stage One Single Ventricle Repair

Abstract

This in vitro study compares the hemodynamic performance of the Norwood and the Glenn circulations to assess the performance of a novel assisted bidirectional Glenn (ABG) procedure for stage one single ventricle surgery. In the ABG, the flow in a bidirectional Glenn procedure is assisted by injection of a high-energy flow stream from the systemic circulation using an aorta-caval shunt with nozzle. The aim is to explore experimentally the potential of the ABG as a surgical alternative to current surgical practice. The experiments are directly compared against previously published numerical simulations. A multiscale mock circulatory system was used to measure the hemodynamic performance of the three circulations. For each circulation, the system was tested using both low and high values of pulmonary vascular resistance. Resulting parameters measured were: pressure and flow rate at left/right pulmonary artery and superior vena cava (SVC). Systemic oxygen delivery (OD) was calculated. A parametric study of the ratio of ABG nozzle to shunt diameter was done. We report time-based comparisons with numerical simulations for the three surgical variants tested. The ABG circulation demonstrated an increase of 30-38% in pulmonary flow with a 2-3.7 mmHg increase in SVC pressure compared to the Glenn and a 4-14% higher systemic OD than either the Norwood or the Glenn. The nozzle/shunt diameter ratio affected the local hemodynamics. These experimental results agreed with those of the numerical model: mean flow values were not significantly different (p > 0.05) while mean pressures were comparable within 1.2 mmHg. The results verify the approaches providing two tools to study this complicated circulation. Using a realistic experimental model we demonstrate the performance of a novel surgical procedure with potential to improve patient hemodynamics in early palliation of the univentricular circulation.

A method to quantify mechanobiologic forces during zebrafish cardiac development using 4-D light sheet imaging and computational modeling

“…Additionally, using the same solver, we also performed benchmark fluid dynamics and FSI tests for code verification in Esmaily-Moghadam et al [ 39 ] and against experimental data for cardiovascular applications. [ 66 , 67 ] We also validated our solver with dynamic remeshing against PIV-based three-dimensional three-component (3D-3C) velocity measurements of ventricular hemodynamics and demonstrated a reasonable agreement with measured data. [ 68 , 69 ]…”

Optimization of the Assisted Bidirectional Glenn Procedure for First Stage Single Ventricle Repair

“…With reference to our previous studies on the ABG physiology, 7,9 this study aimed to optimize the ABG shunt design. To this end, this study explores a much larger design space for the ABG shunt for three values of PVR, compared to our prior investigations.…”

“…By adopting a highly restricted flow from the innominate artery to the SVC, instead of to the branch PAs, we have previously demonstrated acceptable SVC pressures concomitant with improved systemic oxygen saturation. 7,9…”

Computational modeling and engineering in pediatric and congenital heart disease

“…Simulations and in vitro experiments demonstrated decreased cardiac workload, increased pulmonary blood flow, and increased oxygen delivery. [49] If used as a stage one surgery, this could offer the possibility of condensing the first two stages of single ventricle repair into one, although substantially more evidence and animal studies are needed prior to considerations of clinical translation.…”