Early Valve Replacement Guided by Biomarkers of LV Decompensation in Asymptomatic Patients With Severe AS

Aortic stenosis is the most common valvular disease in the Western world. It is caused by progressive narrowing of the aortic valve leading to increased strain on the heart muscle which has to work increasingly hard to pump blood through the narrowed valve. Over time the heart muscle thickens to generate more force, but eventually the heart fails leading to death if the valve is not replaced with an operation. No medical treatments exist to stop or reverse the heart valve narrowing. Current clinical guidelines suggest that an operation should be performed only when symptoms develop or the heart muscle is visibly weak on cardiac ultrasound scanning. However, symptoms can be difficult to interpret and in many patients the heart muscle has become irreversibly damaged and the heart fails to recover following surgery. Using MRI scans of the heart, the investigators have identified heart scarring which seems to develop as the heart muscle thickens. Several studies now show that people who have developed this scarring are more likely to suffer poor outcomes including death. The investigators have also identified clinical risks that predict the presence of scarring. The investigators propose a study where patients with severe aortic stenosis but no indications for valve replacement as per current guidelines are assessed for those clinical risks. If a participant's risk of having scarring is higher they will undergo a cardiac MRI scan. If scarring is present participants will be randomised to routine clinical care, or referral for valve replacement surgery. Participants with no evidence of scarring will be randomised routine care with study follow or not. The investigators of this study hypothesize that early surgery will lead to fewer complications and reduced risk of death compared to standard care.

Inclusion Criteria: 1. Severe aortic stenosis (aortic valve jet velocity ≥4.0 m/s, or aortic valve area indexed to body surface area \180 or diastolic \>110 mmHg) 5. Acute pulmonary oedema or cardiogenic shock 6. Left ventricular ejection fraction \