Objectives: The difference between mean arterial pressure (MAP) before cardiopulmonary bypass (CPB) and mean perfusion pressure (MPP) during CPB is thought to be a strong predictor of acute kidney injury (AKI). In this study, we aimed to evaluate whether the difference between MAP and MPP is a good index to predict the development of AKI and what the ideal MPP should be during CPB.

Methods: A total of 296 consecutive patients were included in this retrospective study. MAP-MPP differences of patients who developed AKI and those who did not develop AKI according to standard guidelines and their relation with adverse outcomes were evaluated.

Results: MAP values of patients who did not develop AKI and patients who developed AKI were higher in the group with AKI, 67.60 mmHg versus 64.84 mmHg (p = 0.001). The MAP-MPP difference was 5.07 in the group without AKI and 9.44 in the group with AKI (p = 0.000).

Conclusion: We found that the difference between MAP and MPP is a good index for predicting the development of CPB-related AKI and poor outcomes. We also suggest that patients’ preoperative arterial blood pressure should be taken into account for an ideal MPP.