Interesting paper in the specific setting of CABG: the baseline pulse pressure, but not the duration of hypo/hypertension correlates with risk of post op AKI. Similarly, in another study (involving a much wider variety of patients), even though tight BP management versus standard therapy may overall reduce complications, it doesn't seem so specifically for AKI (only having a trend towards RIFLE injury criteria, and not significant for R/L/need for RRT); but cardiac/infective/CNS complications are certainly higher .
This really flies in the face of the dogma saying that keeping tight hemodynamics prevents AKI. Like usual, maybe patients just improve/deteriorate regardless of what you do/don't do (though you could be happy that your efforts help with preventing cardiac/infective/CNS complications).