COR LOE Recommendations In adults with severe high-gradient AS (Stage D1) and symptoms of exertional dyspnea, HF, angina, syncope, or presyncope by history or on exercise testing, AVR is indicated.1 7 In asymptomatic patients with severe AS and an LVEF <50% (Stage C2), AVR is In asymptomatic patients with severe AS (Stage C1) who are undergoing cardiac surgery for other indications, AVR is In symptomatic patients with low-flow, low- gradient severe AS with reduced LVEF (Stage In symptomatic patients with low-flow, low- gradient severe AS with normal LVEF (Stage D3), AVR is recommended if AS is the most likely cause of symptoms.25 27 In apparently asymptomatic patients with severe AS (Stage C1) and low surgical risk, AVR is reasonable when an exercise test demonstrates decreased exercise tolerance (normalized for age and sex) or a fall in systolic blood pressure of 10 mmHg from baseline to peak exercise.13,28 30 In asymptomatic patients with very severe AS (defined as an aortic velocity of 5 m/s) and low surgical risk, AVR is reasonable.15,31 35 In apparently asymptomatic patients with severe AS (Stage C1) and low surgical risk, AVR is reasonable when the serum B-type natriuretic peptide (BNP) level is >3 times normal.32,36 38 In asymptomatic patients with high-gradient severe AS (Stage C1) and low surgical risk, AVR is reasonable when serial testing shows an increase in aortic velocity 0.3 m/s per year.39,40 In asymptomatic patients with severe high- gradient AS (Stage C1) and a progressive decrease in LVEF on at least 3 serial imaging studies to <60%, AVR may be In patients with moderate AS (Stage B) who are undergoing cardiac surgery for other indications, AVR may be considered. Synopsis See the table of recommendations for a summary of recommendations from this section and Figure 2 for indications for AVR in patients with AS. 