TABLE 2.

The Toronto Risk Score for adverse events following cardiac surgery

Variable	OR (95% CI)	Regression coefficient	Weight
Age
65 to 74 years	1.4 (1.3 to 1.7)	0.074	1
≥75 years	1.7 (1.4 to 2.1)	0.226	2
Female sex	1.5 (1.3 to 1.7)	0.404	2
LV grade 3 (LVEF 20% to 40%)	1.5 (1.3 to 1.7)	−0.068	2
LV grade 4 (LVEF less than 20%)	2.5 (1.9 to 3.3)	0.515	3
Urgent priority	1.5 (1.3 to 1.8)	−0.312	1
Emergent priority	5.1 (3.9 to 6.7)	0.846	6
MI < one month preoperation	1.4 (1.2 to 1.7)	0.353	1
Redo CABG	3.1 (2.5 to 3.9)	1.106	4
Triple vessel disease	1.4 (1.2 to 1.6)	0.286	1
Left main disease	1.4 (1.1 to 1.6)	0.312	1
Congestive heart failure	1.5 (1.3 to 1.8)	0.326	2
Renal insufficiency	2.1 (1.6 to 2.6)	0.718	2
Diabetes	1.2 (1.1 to 1.4)	0.205	1
Peripheral vascular disease	1.4 (1.2 to 1.7)	0.296	1
Hypertension	1.2 (1.0 to 1.3)	0.142	1
Complex valve	1.3 (1.1 to 1.6)	0.295	2
Other pathology	1.9 (1.5 to 2.2)	0.617	2
Constant	–	−2.595	–

Risk weights are summed to calculate the Toronto Risk Score. Referrent values are zero for the following: age younger than 65 years, male sex, left ventricle (LV) grades 1 or 2 (LV ejection fraction [EF] greater than 40%), elective surgery, no myocardial infarction [MI]) within the month before surgery, no previous coronary artery bypass graft surgery (CABG), less than three vessel coronary artery disease, no left main disease, no congestive heart failure, no renal insufficiency, no diabetes, no peripheral vascular disease, no hypertension, isolated CABG, simple valve surgery (only one valve, no CABG, no other procedures), no other pathology requiring surgical correction. Predicted probability of adverse events (Prob_AE) can be calculated from the following formula: Prob_AE = Σe^β/(1+Σe^β), where e is the exponent and β is the regression coefficient