ACHD indicates adult congenital heart disease; CPET, cardiopulmonary exercise test; ECG, electrocardiogram; SubAS, subaortic stenosis; and TTE, transthoracic echocardiogram. Recommendations for Congenital Valvular Aortic Stenosis (Continued) COR LOE Recommendations Table 19. Congenital Aortic Stenosis: Routine Follow-Up and Testing Intervals* Stage Frequency of Echocardiogram Progressive (Stage B) Every 3 5 y (mild severity, Vmax 2.0 2.9 m/s) Every 1 2 y (moderate severity, Vmax 3.0 3.9 m/s) Severe (Stage C) Every 6 12 mo (Vmax 4.0 m/s) Aortic dilation >4.5 cm Every 12 mo (echocardiogram, MRI or CT) *Modified from existing GDMT for valvular heart disease.S4.2.4-5 CT indicates computed tomography; GDMT, guideline-directed management and therapy; MRI, magnetic resonance imaging; and Vmax, maximum velocity. CLINICAL STATEMENTS AND GUIDELINES Given the association of these abnormalities, eval- uation of patients with BAV for CoA is warranted. 2. BAV is the most prevalent congenital cardiac abnormality with an estimated prevalence of 4.6 per 1000 live births, and is 1.5 times more prevalent in males than females.S4.2.4-7 S4.2.4-13 Most cases are spontaneous; however, familial inheritance may occur in an autosomal domi- nant pattern with variable penetrance. On ech- ocardiographic screening, 1 study reports the prevalence of asymptomatic BAV in first-degree relatives of patients is 9%, and 32% of first-de- gree relatives without a BAV will have an ab- 3. Calcification of the aortic valve in adults neces- sitates that most patients who require therapy for aortic stenosis will require aortic valve re- placement per GDMT.S4.2.4-5 However, young patients with congenitally abnormal valves and relatively little calcification may be candidates for balloon valvuloplasty. Balloon valvuloplasty may improve the degree of stenosis and symp- toms in patients with mobile noncalcified BAV stenosis. In general, the valves that would be amenable to successful balloon valvuloplasty are found in young patients, who are often <25 years of age. 