Fig. 1
Flow chart showing the study population selection process. A total of 172 patients with ACS underwent PCI between October 2015 and January 2017; 23 patients were excluded based on the following criteria: a 10 patients with cardiogenic shock prior to admission; b 6 patients required IABP due to heart failure or severe coronary disease; c 2 patients required chronic haemodialysis; d 3 patients were exposed to CM within the previous 7 days; e 2 patients with severe obesity (body mass index> 40 kg/m2. Besides, 3 patients declined to sign the written informed consent. Finally, 146 patients were enrolled and analysed in this prospective study. ACS: acute coronary syndrome; PCI: percutaneous coronary intervention; IABP: intra-aortic balloon pump; CM: contrast medium