Right Ventricle to-PA Conduit: Routine Follow-Up and Testing Intervals Frequency of Routine Follow-Up and Testing Physiological Stage A* (mo) Physiological Stage B* (mo) Physiological Stage C* (mo) Physiological Stage D* (mo) Exercise test As needed As needed 12 24 12 24 *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 right ventricular size and function and valvular function, conduit anatomy and pulmonary artery anatomy. 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. If CCT is used instead of CMR imaging, the frequency should be weighed against radiation exposure. 6-minute walk test or CPET, depending on clinical indication. ACHD indicates adult congenital heart disease; CCT, cardiac computed tomography; CMR, cardiovascular magnetic resonance; CPET, cardiopulmonary exercise test; ECG, electrocardiogram; PA, pulmonary artery; and TTE, transthoracic echocardiogram. CLINICAL STATEMENTS AND GUIDELINES or transcatheter conduit intervention to relieve ste- nosis and/or regurgitation. Transcatheter stenting and pulmonary valve replacement may be per- formed with high procedural success and low mor- tality rates, and result in improved hemodynamics and improved exercise capacity. Surgical conduit replacement carries a higher risk of periprocedural complications with good long-term outcomes. Predictors of conduit dysfunction and reopera- tion include placement of small diameter conduits; therefore, insertion of conduits with the largest possible diameter should be attempted,S4.3.6-8 antic- ipating that subsequent valve replacement may be via a transcatheter approach. 5. 