Age, years	65 to 74; ≥75
Female	Female sex
Left ventricle (LV) grade
1	LV ejection fraction (EF) greater than 60%
2	LVEF 40% to 59%
3	LVEF 20% to 39%,
4	LVEF less than 20%
Urgent priority	Surgery within 72 h of catheterization, echocardiography or cardiac event
Emergent priority	Surgery within 12 h of catheterization, echocardiography or cardiac event
Myocardial infarction less than one month	Myocardial infarction within 30 days before operation
Redo coronary artery bypass graft surgery(CABG)	Previous CABG surgery
Triple vessel disease	Significant (greater than 50%) stenosis of all three major coronary arteries
Left main disease	Significant (greater than 50%) stenosis of the left main coronary artery
Congestive heart failure (CHF)	CHF or history of chronic CHF at the time of admission
Renal insufficiency	Any renal dialysis or serum creatinine greater than 150 μmol/L
Diabetes	Any diabetes regardless of method of control/treatment
Peripheral vascular	Peripheral vascular disease including carotid or cerebral vascular disease
Hypertension	History of hypertension regardless of control
Chronic obstructive pulmonary disase	Chronic obstructive lung disease diagnosed by pulmonary function tests
Cerebral vascular event	Preoperative cerebral vascular event either stroke or transient ischemic attack
Atrial fibrillation	History of atrial fibrillation/flutter preoperatively
Complex valve	Surgery on more than one valve, or concomitant CABG or more than one previous valve operation
Other pathology	Surgery other than, or in addition to, CABG or valve or complex valve; may include: LV aneurysm resection, ascending aorta, adult congenital, maze procedure, myectomy, ventricular assist devices, septal repair, implantation of ventricular assist devices, transplants, etc