Towards Improved Understanding and Treatment of Failing Fontan Circulation

Fontan circulation is a surgically-modified vasculature used to treat patients born with a single functioning heart ventricle. This surgery has low early mortality; however, adult Fontan patients have a 20x higher risk of... [ view full abstract ]

Fontan circulation is a surgically-modified vasculature used to treat patients born with a single functioning heart ventricle. This surgery has low early mortality; however, adult Fontan patients have a 20x higher risk of death than the general population. Treatment for failing Fontan circulation is a heart transplant, but little understanding of the timing of disease progression and a lack of medical devices for bridging to transplant causes many failing Fontan patients to die before receiving a donor heart.

Our research goals are to improve our understanding of failing Fontan circulation and to develop a minimally-invasive medical device as a bridge to transplant for these patients. As a first step towards achieving these goals, we have developed a computational fluid dynamics model of the Fontan pathway based on an average measurements from 10 pediatric (4-5 years old) Fontan patients. This model is coupled to a lumped parameter model of the rest of the circulation, which consists of resistive and compliant elements, and a single ventricle heart. We simulated the hemodynamics of healthy and failing Fontan circulations and found a difference in cardiac index (3.6 vs. 2.4 L/min/m^2) and Fontan pressure (14.2 vs. 19.9 mm Hg) (Fig. 1) between the two cases.

We are presently refining our computational model and, using clinical data, extending the model to juvenile and adult patients. We will use these models to gain insight in the hemodynamics factors that are indicative of failing Fontan circulation, as well as in the design of our minimally-invasive medical device.