Definitions of variables

Variable	Definition
CK, creatine kinase; CVA, cerebrovascular accident; GIT, gastrointestinal tract; iv, intravenous; MI, myocardial infarction; TIA, transient ischaemic attack.
Symptom status (stable)	No recent deterioration and no unstable angina
Smoking	Past or present
Renal problems	• Serum creatinine ⩾200 μmol/l
	• Acute or chronic renal failure requiring haemodialysis
GIT problems	• Diagnosed hiatus hernia
	• Diagnosed peptic ulcer disease
	• Diagnosed pancreatitis
	• GIT bleeding
Respiratory problems	• Chronic obstructive airway disease
	• Bronchial asthma requiring the use of inhalers
Peripheral vascular disease	Chronic ischaemia of lower limbs
Perioperative MI	Presence of at least one of the following:
	• New Q waves in the ECG
	• CK-MB >50 with ECG changes
	• CK-MB >70 without ECG changes
Cardiogenic shock (iv inotropes)	Up till operating theatre
CVA or TIA	• TIA when the neurological deficit lasted <24 hours
	• CVA when the neurological deficit lasted >24 hours
Low cardiac output	In absence of the previously described perioperative MI criteria, when the systolic arterial blood pressure was persistently <90 mm Hg or the mean arterial blood pressure was persistently below <50 mm Hg despite appropriate fluid management and requiring inotropic or vasoconstrictor treatment
Infective complications	• Septicaemia
	• Sternal wound infection
	• Conduit harvest site infection
Pulmonary complications	• Adult respiratory distress syndrome
	• Reintubation/tracheostomy
	• Pleural effusion
	• Pneumothorax
Renal complications	New occurrence of one of the following:
	• Serum creatinine ⩾200 μmol/l
	• Renal failure requiring haemodialysis
GIT complications	Postoperative occurrence of one of following:
	• Peptic ulceration
	• Pancreatitis
	• Mesenteric infarction
	• GIT bleeding
	• Perforation