Severe aortic stenosis is defined with a mean transvalvular pressure gradient (MTPG) > 40mmHg and a calculated aortic valve area of < 1cm2. However, a considerable proportion of patients do have a MTPG < 40mmHg due to a reduced stroke volume (stroke volume indexed to body surface area ≤ 35ml/m2) despite a normal left ventricular ejection fraction (LVEF > 50%). This entity is termed paradoxical low flow low gradient aortic stenosis (PLFLG AS) and is associated with a worse prognosis.

ATTR amyloidosis is a disease of the elderly and might coexist in patients with severe aortic stenosis. Case reports and small observational studies suggest that senile ATTR amyloidosis could be frequent but underdiagnosed in patients with aortic stenosis. There is significant overlap between PLFLG AS and cardiac amyloidosis with regard to symptoms, increasing prevalence with age, concentric hypertrophy, impaired diastolic filling of the left ventricle (LV), as well as longitudinal LV dysfunction despite preserved ejection fraction - all features, which lead to a reduction in stroke volume, the underlying mechanism of the low flow condition as observed in PLFLG AS patients.

Inclusion Criteria:

• Symptomatic, severe aortic stenosis

Exclusion Criteria:

• More than mild valvular disease of any other valve
• Other severe disease with a life expectancy < 1 year
• Participating in trial interfering with routine clinical practice or use of a non-CE marked device

Patients with symptomatic, severe aortic stenosis undergoing pre-evaluation for (transcatheter) aortic valve replacement