PCSK9 and metabolic syndrome: The lifespan of BHVs primarily depends on crosslinks introduced by glutaraldehyde or the ethylene glycol diglycidyl ether fixation of xenogeneic tissue, though it is also negatively impacted by young age, prosthesis–patient mismatch, arterial hypertension, dyslipidemia, diabetes mellitus, metabolic syndrome, chronic kidney disease, increased levels of calcium-phosphate product, lipoprotein-associated phospholipase A2 and proprotein convertase subtilisin/kexin type 9 in plasma, and the absence of hypolipidemic and anticoagulant therapy [7,26,27,28,29,30,31,32,33,34,35].