Achilles Tendon Xanthoma Thickness and Carotid Intima-Media Thickness in a Patient With Heterozygous Familial Hypercholesterolemia on PCSK9 Inhibition: A Case Report and Literature Review.

Ultrasound-guided measurement of carotid intima-media thickness can be used as a surrogate marker to predict future risk of atherosclerotic cardiovascular disease, and to understand the efficacy of lipid-lowering drugs. Aggressive lipid-lowering drugs such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been shown to reduce carotid artery plaque burden, total cholesterol, and low-density lipoprotein-c in patients with heterozygous familial hypercholesterolemia (FH). We describe a patient with heterozygous FH treated with PCSK9 inhibitor over the course of two years, and the drug's impact on carotid intima-media thickness, Achilles tendon thickness, and cardiovascular disease risk reduction.