COR LOE Recommendations Diagnostic IIa C-EO Cardiac catheterization can be useful in adults with atrioventricular septal defect when pulmonary hypertension is suspected. Therapeutic I C-LD Surgery for severe left atrioventricular valve regurgitation is recommended per GDMT indications for mitral I C-EO Surgery for primary repair of atrioventricular septal defect or closure of residual shunts in adults with repaired atrioventricular septal defect is recommended when there is a net left-to-right shunt (Qp:Qs 1.5:1), PA systolic pressure less than 50% systemic and pulmonary vascular resistance less than one third systemic. IIa C-EO Operation for discrete LVOT obstruction in adults with atrioventricular septal defect is reasonable with a maximum gradient of 50 mm Hg or greater, a lesser gradient if HF symptoms are present, or if concomitant moderate-to-severe mitral or AR are present. Table 14. VSD: 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) Pulse oximetry As needed As needed Each visit Each visit Exercise test As needed As needed 12 24 6 12 *See Tables 3 and 4 for details on the ACHD AP classification system. 6-minute walk test or CPET, depending on the clinical circumstance. ACHD indicates adult congenital heart disease; CPET, cardiopulmonary exercise test; ECG, electrocardiogram; TTE, transthoracic echocardiogram; and VSD, ventricular septal defect. CLINICAL STATEMENTS AND GUIDELINES Therapeutic (Continued) IIb C-EO Surgery for primary repair of atrioventricular septal defect or closure of residual shunts in adults with repaired atrioventricular septal defect may be considered in the presence of a net left-to-right shunt (Qp:Qs 1.5:1), if PA systolic pressure is 50% or more systemic, and/or pulmonary vascular resistance is greater than one third systemic. 