FABP1 and acute kidney injury: Considering the null hypothesis was the absence of difference in the L-FABP level between AKI and No-AKI groups and considering the previously documented AKI incidence rate during interventional cardiology which was 29.5% [24] and 36% [25], so to achieve a similar incidence of AKI, using α error 5% and a power of 80%, and considering the required sample size for AKI group must be 85 patients, the total patients' number must be 250 to get an AKI incidence of 34%.