REN and aortic stenosis: There are no randomized controlled trials on the best medical treatment in patients with risk of heart failure after valve intervention in severe aortic stenosis.11 The renin–angiotensin–aldosterone system (RAS) is involved in the regulation of myocardial fibrosis, and RAS inhibition with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers has been shown in several studies to reverse left ventricular remodelling and left ventricular fibrosis and improve survival in patients with heart failure with reduced ejection fraction.12–14