Cardiac amyloidosis: an unusual cause of low flow–low gradient aortic stenosis with preserved ejection fraction

Both low flow–low gradient aortic stenosis (LFLG AS) despite preserved ejection fraction (EF) and cardiac amyloidosis (CA) can be observed in elderly patients with left ventricular (LV) hypertrophy, apparently normal LV systolic function but severe longitudinal dysfunction. We report a case of a patient in whom the pattern of LFLG AS was associated with and related to an associated CA. An 84-year-old man with hypertension and permanent atrial fibrillation (AF) was referred for congestive heart failure. Electrocardiogram revealed AF and left bundle branch block. Echocardiography found an increased LV wall thickness (Panel A, Supplementary data online, Videos S1 and S2). EF was 72%. Global longitudinal strain was –10.5%, with longitudinal dysfunction predominating in the basal segments with apical sparing (Panel A). Aortic valve was heavily calcified (see Supplementary data online,Supplementary Data) with an LFLG AS pattern (mean gradient = 32 mmHg, stroke volume index = 35 mL/m2, indexed aortic valve area = 0.38 cm2/m2) (Panel B). High brain natriuretic peptid level (582 ng/L) and elevated kappa light chains (29.5 mg/L) were observed. 99mTc-HMDP scintigraphy showed severe cardiac uptake (Panel C). Valve calcium score was high (3925), suggesting severe AS (Panel D). However, associated CA was suspected because of the echocardiographic and strain patterns, and was confirmed by endomyocardial biopsies.