27th May 2023

A 60-year-old patient presents to their GP with lethargy and pallor

A 60-year-old patient presents to their GP with lethargy and pallor. She has a background of a bicuspid aortic valve for which she had an aortic valve replacement 20 years ago. She has otherwise been well, takes warfarin only but has a stable therapeutic INR, and has not travelled abroad in the last year.  On auscultation of her chest, an audible metallic second heart sound is heard. Blood tests show Hb 90 g/L and MCV 88 fL. DAT is negative.

Of the options below, which is the most likely diagnosis?