### Description

Jorge-Monjas et al developed the CRATE score for predicting the risk of cardiac surgery-associated acute kidney injury (CSA-AKI). These can help to identify a patient who may benefit from more aggressive renal management or an alternative management strategy. The authors are from the University of Valladolid and Hospital Universitario de la Princesa in Madrid.

Parameters:

(1) serum creatinine (CR) in mg/dL

(2) lactic acid (A) during surgery in mg/dL

(3) cardiopulmonary bypass (CPB) time (T) in minutes

Parameter

Finding

Points

serum creatinine

<= 0.96 mg/dL

18

0.97 to 1.26

25

1.27 to 1.49

30

>= 1.50 mg/dL

39

lactate

<= 17.8 mg/dL

5

18.0 to 23.9

6

24 to 36.8

9

36.9 to 51.0

13

>= 51.1 mg/dL

21

CPB time

<= 81 minutes

7

82 to 104

9

105 to 138

12

139 to 181

15

>= 182 minutes

20

Euroscore

<= 2

7

3 to 4

10

5 to 7

20

8 to 10

30

>= 11

40

total score =

= SUM(points for all 4 parameters)

Interpretation:

• minimum score: 37

• maximum score: 120

• The higher the score the greater the risk of acute kidney injury.

Total Score

Percent AKI

AKI Risk

< 50

4%

very low

50 to 70

27%

low

70 to 80

47%

moderate

80 to 90

64%

high

> 90

100%

very high

Alternatively:

Y =

= (0.114 * (CRATE)) – 9.24

probability of AKI =

= 1 / (1 + EXP((-1) *Y))

Alternatively a logistic regression model can be used:

X = (0.336 * (Euroscore)) + (0.01 * (CPB)) + (0.031 * (lactate)) + (2.268 * (creatinine)) – 8.422

where:

• The lactate has units of mmol/L vs mg/dL in the rest of the paper.

proability of AKI =

= 1 / (! + EXP((-1) * X))

Performance:

• The area under the ROC curve was 0.81.