GDF15 and acute coronary syndrome: ACS, acute coronary syndrome; CKD, chronic kidney disease; CVS, cardiovascular; eGFR, estimated glomerular filtration rate; GDF-15, growth differentiation factor 15; MACE, major adverse cardiovascular events; MI, myocardial infarction; NT-pro-BNP, N-terminal prohormone of brain natriuretic peptide