ACE2 and aortic stenosis: Mean ACE2 activity in patients with severe aortic stenosis (AS) (88.3 ± 61.6, n = 111, vs. 20.6 ± 13.4, n = 540, Fig. 1a and b) is about 4-fold higher than in hypertensive patients and 6-fold higher than in healthy individuals (16.1 ± 7.4 mU/L, n = 46, 1A and 1B).