- Aortic valve area of ≤1.0 cm2 (or aortic valve area index of ≤0.6 cm2/m2), AND a mean gradient ≥40 mmHg or maximal aortic valve velocity ≥4.0 m/sec by transthoracic echocardiography, AND an exercise tolerance test that demonstrates a limited exercise capacity, abnormal BP response, or arrhythmia OR