An Automated Simulation Protocol for Exercise Physiology in Fontan Patients Using a Closed-Loop Lumped-Parameter Model

Modeling efforts to describe Fontan physiology have mainly focused on the effects of variations in Fontan geometry, and typically have not considered the range of hemodynamic conditions that can occur within the patient population. A few exceptions have used open loop models to simulate exercise conditions2, however numerous assumptions were required for increasing flow rates, changing waveform shapes, and prescribing changes in pulmonary vascular resistances. In addition, there has been essentially no validation of exercise simulations against clinical data. In this study, we address these previous deficiencies by introducing a well-defined protocol for automated simulations of Fontan lower-body exercise with a closed-loop lumped-parameter model (LPN). Using inputs of patient weight, height, and if available, a patient-specific reference heart rate and oxygen consumption, this protocol enables the derivation of a full set of parameters necessary for simulating a standard Fontan patient of a particular body size at any physiologic exercise level. Applying this method retrospectively to a set of clinical data, we performed the first direct comparison between simulation predictions and clinical exercise data.