A novel Fontan Y-graft for interrupted inferior vena cava and azygos continuation

Abstract

OBJECTIVES To evaluate the hemodynamicdynamic advantage of a new Fontan surgical template that is intended for complex single-ventricle patients with interrupted inferior vena cava-azygos and hemi-azygos continuation. The new technique has emerged from a comprehensive pre-surgical simulation campaign conducted to facilitate a balanced hepatic flow and somatic Fontan pathway growth after Kawashima procedure. METHODS For 9 patients, aged 2 to18 years, majority having poor preoperative oxygen saturation, a pre-surgical computational fluid dynamics customization is conducted. Both the traditional Fontan pathways and the proposed novel Y-graft templates are considered. Numerical model was validated against in vivo phase-contrast magnetic resonance imaging data and in vitro experiments. RESULTS The proposed template is selected and executed for 6 out of the 9 patients based on its predicted superior hemodynamic performance. Pre-surgical simulations performed for this cohort indicated that flow from the hepatic veins (HEP) do not reach to the desired lung. The novel Y-graft template, customized via a right- or left-sided displacement of the total cavopulmonary connection anastomosis location resulted a drastic increase in HEP flow to the desired lung. Orientation of HEP to azygos direct shunt is found to be important as it can alter the flow pattern from 38% in the caudally located direct shunt to 3% in the cranial configuration with significantly reversed flow. The postoperative measurements prove that oxygen saturation increased significantly (P-value = 0.00009) to normal levels in 1 year follow-up. CONCLUSIONS The new Y-graft template, if customized for the individual patient, is a viable alternative to the traditional surgical pathways. This template addresses the competing hemodynamic design factors of low physiological venous pressure, high postoperative oxygen saturation, low energy loss and balanced hepatic growth factor distribution possibly assuring adequate lung development. Date and number of IRB approval 25 October 2019, 280011928-604.01.01.

A case report of Y-shaped bi-directional Fontan procedure: promising long-term outcomes for single ventricle physiology patients

“…Pre-surgical simulations carried out on 9 individuals in Lashkarinia et al 's Y transplant fontan study [13] revealed that flow from the hepatic veins (HEP) was not reaching the target lung. The HEP flow to the target lung was dramatically increased by the innovative Y-graft template.…”

Evaluation of the total hydrodynamic energy loss using 4D flow MRI in a case with Fontan failure

“…Total energy loss (EL) is an emerging clinical hemodynamic parameter representing the pulsatile energy lost due to the blood flow as it flows through the cardiovascular component volume. It is utilized routinely in the pre-surgical planning of Fontan conduits [ 6 ]. 4D flow MRI is a useful tool to estimate the EL in the Fontan system and can explain the cause of FF [ 7 ].…”

“…Here, we present a case with FF presenting with severe ascites. Although echocardiography and cardiac catheterization show normal findings, an interventional approach was initiated and judged according to the comparative EL levels calculated with 4D flow MRI [ 6 , 8 , 9 ].…”

In Vitro Hemodynamic Performance of a Blood Pump for Self-powered Venous Assist in Univentricular Hearts

“…As the population of late survivors with Fontan circulation continues to grow and donor organ shortages persist, the management of Fontan failure has become a signi cant clinical challenge, and innovative strategies are urgently required [15]. Attempts aimed at addressing the Fontan paradox have primarily focused on optimizing the TCPC anatomy to improve blood energetics through novel surgical pathways, such as Y-grafts [16][17][18][19][20][21]. These modi cations, however, fail to address the physiologic de cit of a ventricle as the right-side driving pump and thus have little impact on the Fontan outcomes [22].…”