PCSK9 and acute coronary syndrome: In a prospective observational study, a direct association between elevated PCSK9 serum levels and higher platelet reactivity was found, and it predicts that elevated PCSK9 serum levels will be a predictor of ischemic events after percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) patients in the future (Navarese et al., 2017).