Consequently, strength training may improve exercise capacity in patients with Fontan palliation. 6. There is increasing recognition of hepatic vul- nerability after Fontan palliation, including but uncertainty about which patients are at highest risk, or how to address problems when identified. Routine assessment of liver function and structure may help inform broader decisions such as timing and risk of sur- gery or transplantation, as well as provide insights into the emerging natural history of this unique condition. Consultation with a hepatologist may be of value in interpreting and following the liver abnormalities encountered in patients with Fontan physiology. 7. Recognizing the multiorgan vulnerability of the Fontan circulation, annual routine blood tests Table 32. Fontan Palliation: Routine Follow-Up and Testing Intervals Frequency of Routine Follow-Up and Testing Physiological Stage A* (mo) Physiologic al Stage B* (mo) Physiological Stage C* (mo) Physiological Stage D* (mo) Pulse oximetry 12 12 Each visit Each visit *See Tables 3 and 4 for details on the ACHD AP classification system. Routine TTE may be unnecessary in a year when CMR imaging is performed unless clinical indications warrant otherwise. CMR may be indicated for assessment of the long-term sequelae of Fontan palliation: thrombosis, right-to-left shunts (eg, fenestration. intrapulmonary atrioventricular malformation), obstructive lesion, systemic atrioventricular valve dysfunction, ventricular size and function, collateral burden, and branch pulmonary artery obstruction. Baseline study is recommended with periodic follow- up CMR, with frequency of repeat imaging determined by anatomic and physiological findings. CCT may be used if CMR is not feasible and to evaluate cross-sectional imaging status-post stent therapy. CCT with contrast injection in Fontan patients can be misleading; therefore, it should be done only when clinically indicated and when it can be appropriately protocoled and interpreted. 