The Role of Occult Cardiac Amyloid in the Elderly With Aortic Stenosis.

Aortic stenosis (AS) is the most common valvular heart disease. Once symptomatic with severe AS, outcome is poor unless the valve is replaced surgically or via transcatheter aortic valve replacement (TAVR). Transthyretin amyloid (ATTR) deposits are common in the heart muscle in up to 25% of octogenarians, and after an asymptomatic period of unknown duration, cause overt heart failure and arrhythmias in a proportion of cases. The prevalence and impact of covert ATTR amyloidosis in elderly individuals with AS are unknown. Detection would avoid misdiagnosis, guide treatment and, potentially, improve outcomes. Recent data have shown that echocardiography, cardiovascular magnetic resonance (CMR), computed tomography (CT), and DPD scintigraphy, can identify ATTR amyloid deposits, but the clinical performance of these various tests is unknown. This study will investigate elderly patients with symptomatic severe AS using imaging to explore ATTR amyloid in AS and determine its prevalence and impact on outcome. The investigators aim to recruit a total of 250 patients aged 75 or older being considered for intervention for severe AS. The prevalence of cardiac amyloid will be assessed in three arms (sAVR, TAVI and medical therapy, with a likely patient ratio of 50:150:50), using five investigation modalities - all cohorts (echocardiography and DPD scintigraphy); sAVR cohort (biopsy and CMR); TAVI cohort (EqCT); medical therapy only cohort (as per work-up/trial prior to no intervention decision). The primary outcome measure is patient mortality. Secondary outcomes measures are major adverse cardiovascular events, length of stay, pacemaker implantation, ECV measured by EqCT and CMR. Follow up will be at 1-year with clinical echocardiogram (for sAVR and TAVI patients) and/or telephone interview for all patients (if not carried out in person at the time of the echocardiogram).