ONTARIO Score
Sex Age Urgency of surgery (Help)
Male
Female
 		 < 65
65 to 74
> 74		 Elective
Urgent
Emergency
Type of surgery Ejection fraction Repeat operation
CABG only
Single Valve
Complex		 EF > 50%
35 to 50 %
20 to 34 %
EF < 20%		 No
Yes
 
ONTARIO =
Score
Hospital Mortality
ICU lenght of stay
(mean-days)
PostOp lenght of stay
(mean-days)
0
0.25 %
2.27
8.04
1
0.79 %
2.39
8.43
2
1.30 %
2.81
9.25
3
2.89 %
2.89
10.35
4
4.59 %
3.16
10.97
5
5.69 %
3.31
11.44
6
8.13 %
3.68
12.80
7
11.61 %
4.33
13.14
>= 8
13.22 %
5.87
14.51
Risk score and observed rates in validation set (6885 adults patients, 9 institutions)

Ref : Tu JV et al. Multicenter validation of a risk index for mortality, intensive care unit stay, and overall hospital length of stay after cardiac surgery. Circulation. 1995;91:677-84