title: Determination of safe contrast media dosage to estimated glomerular filtration rate ratios to avoid contrast-induced nephropathy after elective percutaneous coronary intervention.
abstract: OBJECTIVE
  To avoid the risk of developing contrast-induced nephropathy (CIN), it has been suggested that patients be subjected to a minimal necessary dose of contrast medium (CM-dose). However, often it is not easy to determine such a dose. This study assessed the usefulness of the ratio of CM-dose to estimated glomerular filtration rate (eGFR) in predicting the risks of CIN and sought to determine the safe level of CM-dose/eGFR in patients undergoing non-emergent percutaneous coronary intervention (PCI).
  
  
  METHODS
  We enrolled a total of 226 patients and calculated the ratio of CM-dose using grams of iodine (g-I) to eGFR, thus expressing it as g-I/eGFR. Among the CIN patients, those with ne-phropathy requiring dialysis (NRD) were also evaluated.
  
  
  RESULTS
  Overall, there were 16 cases (7.1%) of CIN. On univariate and multivariate regression analysis, g-I/eGFR alone was found to be an independent predictor for CIN (hazard ratio=10.73, p<0.001). In an receiver operating characteristic analysis, fair discrimination for CIN was found at a g-I/eGFR level of 1.42 (C statics=0.867), and at this value, the sensitivity and specificity were 81.3% and 80%, respectively. Of patients (n=51) with g-I/eGFR ≥1.42, 23.6% (13/51) and 7.8% (4/51) developed, while those with g-I/eGFR <1.42 (n=171) had a lower incidences of CIN (1.8%, 2/171, p<0.001) and NRD (0%, 0/171, p<0.001).
  
  
  CONCLUSIONS
  It can be concluded that a g-I/eGFR <1.42 is a simple, useful indicator for determining the safe CM-dose based on the pre-PCI eGFR values. Furthermore, g-I/eGFR might have a close relationship with the development of NRD as well as CIN.
authors: Devision of Cardiology, Department of Internal Medicine, Keimyung University Dongsan Medical Center, Daegu, Korea.
authors: Hyuck-Jun
authors: HJ
authors: Yoon
authors: Seung-Ho
authors: SH
authors: Hur