APOA1 and acute myocardial infarction: This study aims to investigate the relationship between serum secreted frizzled‐related protein 5 (SFRP5), apolipoprotein A‐I (ApoA‐I), high‐density lipoprotein 3‐cholesterol (HDL3‐C) and in‐stent restenosis (ISR) after percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) and their combined predictive value.