The SYNTAX score as a predictor of contrast-induced nephropathy patients with chronic total occlusion undergoing percutaneous coronary intervention

Background The SYNTAX score was developed to assess the severity and complexity of coronary artery disease and was determined to be effective in predicting contrast-induced nephropathy(CIN) in patients with STelevation myocardial infarction(STEMI) and non-STEMI(NSTEMI). However, the relationship between SYNTAX score and CIN of patients with CTO undergoing PCI has been unclear. Methods We retrospectively enrolled 667 patients with CTO who underwent our institution′s basic PCI protocol between January 2010 and September 2012. The patients were divided into 3 groups: a low-risk group(SYNTAX score 23; n = 231), a moderate-risk group(SYNTAX score = 23-32; n = 214), and a high-risk group(SYNTAX score32; n = 222). CIN was defined as an absolute increase in SCr of ≥ 0.5 mg/d L over baseline values within 48-72 h after administration of contrast medium. We observed the correlation between SYNTAX score and the CIN rates. Results CIN developed in 74(11.09%) of the 667 study patients. The CIN rate showed a positive trend in the 3 groups based on the SYNTAX score, the higher SYNTAX score corresponds to the higher incidence of CIN(6.93%,13.08%,13.51%P = 0.044). In the multivariate analysis, SYNTAX score was identified as an independent predictor of CIN(OR:1.956,95% CI: 1.014-3.773; P = 0.045; OR: 1.942,95% CI: 1.005-3.752; P = 0.048). The incidence of in-hospital(1.3% vs. 4, 21% vs. 5.86%, P = 0.035) and long-term MACE(4.59% vs. 7.88% vs. 11.66%, P = 0.046) rates were more frequent in the higner SYNTAX score groups. Conclusions SYNTAX score is an independent predictor of CIN among patients with CTO undergoing PCI.