Maastricht Investigation of Renal Function in Absence of- and Post- Contrast in Patients With eGFR LEss Than 30

The current prospective observational study proposes to use intra-patient comparisons of peak changes in renal function (serum creatinine) in absence of- and post- intravascular iodinated contrast administration, to elucidate the relationship between renal function and contrast administration in elective patients with eGFR \<30 mL/min/1.73m2. The effects of contrast administration on risk of 1-month dialysis and mortality will also be evaluated. Daily serum creatinine assays will be done 1. during 5 days before contrast (= in absence of contrast), 2. during 5 days after contrast (= post-contrast), and 3. during 5 days at 1-month post contrast (= 1-month post contrast in absence of contrast). Baseline serum creatinine values will be obtained on the day before each 5-day series. Relevant baseline characteristics of patients will be reported to enable a detailed description of the study population. To explore whether the magnitude of the mean difference in peak change in serum creatinine before and after contrast administration depends on other factors, pre-planned subgroup analyses will be performed. To enable subgroup analyses, data will be collected on 1) prophylactic hydration (yes vs no); 2) administration route (intra-arterial versus intravenous contrast administration); 3) contrast volume (high vs low) and 4) comorbidity (presence vs absence of diabetes).