Wireless Telemetry Device Implantation in a Fontan Ovine Model for Continuous and Long-Term Hemodynamic Monitoring

While the Fontan procedure drastically improves life expectancy for patients with single ventricle, it is well recognized that the resulting circulation causes significant disease burden long term as a consequence of chronically elevated central venous pressures and decreased cardiac output. Chronic Fontan animal models are a valuable asset to studying the late physiological outcomes associated with this operation and a necessary tool in the evaluation of future devices designed to alleviate Fontan failure. However, previous attempts at the creation of chronic Fontan models have been hindered by poor survival rates. Additionally, effective hemodynamic data collection poses a significant challenge in freely moving animals. To this end, the use of wireless implantable telemetry systems provides a novel solution for real-time and long-term monitoring of cardiovascular data. This protocol describes the methodology for surgical implantation of a wireless telemetry device in a Fontan survival ovine model, facilitating the continuous and ongoing recording of several hemodynamic parameters, including heart rate, arterial blood pressure, and localized pressures in the inferior (IVC) and superior vena cava (SVC). Telemetry devices were implanted with cannulation of either the carotid artery and internal jugular vein or femoral artery and vein, for placement of pressure-sensing catheters in the ascending aorta and SVC or abdominal aorta and IVC, respectively. The use of the wireless telemetry systems enabled close postoperative monitoring following a single-stage Fontan operation, which contributed to improved animal welfare and survival.