Description

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a frequent complication after cardiac operations with cardiopulmonary bypass (CPB) use. Its frequency varies depending on the severity grade which for the present study follows the AKIN criteria.

There are different predictive scores for the CSA-AKI based on the patient and surgery-associated parameters. These models could be defined as "static".

It's known that a number of CPB-associated parameters could influence CSA-AKI, as well. These include hematocrit (HCT), oxygen delivery (DO2), time of exposure to a critical DO2, and perfusion pressure. These parameters, taken separately, are associated with CSA-AKI development.

Recently, our Institution has developed a predictive algorithm for CSA-AKI that starts with a static model and then integrated with 7 CPB-associated parameters: HCT, DO2, time of exposure to a critical DO2, systemic pressure, CPB duration time, lactate value, transfusion of red blood cells (RBC), that together build a dynamic perfusion risk (DPR) associated to the CPB. Combining the static and dynamic models produces the Multifactorial Dynamic Perfusion Index (MDPI).

MDPI has higher discrimination power when compared to the static scores, in the original series and in the internal validation with the Bootstrap technique.

The present study validates MDPI in a new prospective series of patients undergoing cardiac surgery with CPB. An enrollment of 400 patients is anticipated with a stopping rule for efficacy at interim analysis (for primary endpoint) at 50% enrollment (200 patients) if the c-statistics for any stage of CSA-AKI reaches at least 0.75. Futility is defined as an AUC of 0.6 or lower.