23. Does the maximum allowable contrast dose (MACD) predict the risk of contrast induced nephropathy (CIN) in patients with chronic kidney disease (CKD)

CIN is associated with high in-hospital mortality. Some studies recommend the utilization of the MACD formula to guide safe contrast dosing, however the evidence supporting use of this measure is limited. Objective: The purpose of this study was to determine if MACD is helpful in predicting the risk of CIN in patients with CKD. Methods: 8670 patients who underwent coronary angiography in our center with or without Percutaneous Coronary Intervention (PCI) (2008–2013) were included. Patients with CKD (n = 144) were selected. Patients in shock, on intra aortic balloon pump, on prophylactic hemofiltration or on dialysis were excluded. Creatinine was measured 48–72 h post procedure. T-test, Chi-Square and multiple regression were used to compare those patients who developed CIN and those who did not develop CIN. CIN was defined as an increase in serum creatinine by ⩾25% or 0.5mg/dL from baseline within 48–72 h after contrast exposure. Results: CIN occurred in 28 patients (19.4%). Only 8 (5.6%) of the 144 patients exceeded MACD and 2 of these patients developed CIN. The use of biplane angiography explains the lower contrast dose. For this reason the impact of exceeding MACD could not be evaluated. Primary PCI was associated with CIN (p = 0.012; OR 5.1)). Conclusion: Overall it is best to limit contrast dose to the extent possible as this is a known risk factor, however MACD is not a useful variable in a risk model for predicting CIN in our population. Primary PCI was the only predictor of CIN in our population