The logistic EuroSCORE identifed the following areas for potential improvement:
• Creatinine clearance (CC) is a better predictor than absolute serum creatinine.
• Hepatic function is not represented.
• Defining unstable angina by the use of intravenous nitrates is out of date.
• Some continuous variables are treated as dichotomous (number of previous heart operations, serum creatinine, pulmonary artery pressure).
• The model is not suffciently sensitive to the ‘weight’ of the intervention.
Hence, the following modifications were done -
The risk factors are -
Patient-related factors –
Age and sex
Height and weight
Neurological or musculoskeletal dysfunction
On dialysis Last serum creatinine
Cardiac-related factors –
Recency and size of last myocardial infarct
Systolic PA pressure
Previous cardiac surgery
Operation-related factors -
Type of procedure(s) performed in detail
Times of Bypass
Deep hypothermic arrest
Selective cerebral perfusion
Defnitions and explanations of the risk factors -
NYHA class - NYHA classi?cation for dyspnoea:
• I: no symptoms on moderate exertion; • II: symptoms on moderate exertion; • III: symptoms on light exertion; • IV: symptoms at rest.
CCS class 4 - CCS class 4 angina (inability to perform any activity without angina or angina at rest).
IDDM - Insulin dependent diabetes mellitus
Extracardiac arteriopathy - One or more of the following: • claudication; • carotid occlusion or >50% stenosis • amputation for arterial disease; • previous or planned intervention on the abdominal aorta, limb arteries or carotids.
Poor mobility –Severe impairment of mobility secondary to musculoskeletal or neurological dysfunction.
Previous cardiac surgery - One or more previous major cardiac operation involving opening the pericardium.
Renal dysfunction - This is assessed by CC as estimated using the Cockcroft–Gault formula and falls into three categories:
• CC 51–85
• on dialysis (regardless of serum creatinine)
Active endocarditis –
Patients still on antibiotic treatment for endocarditis at the time of surgery.
Critical preoperative state - Any one or more of the following occurring preoperatively in the same hospital admission as the operation: • ventricular tachycardia or ?brillation or aborted sudden death; • cardiac massage; • ventilation before arrival in the anaesthetic room; • inotropes; • intra-aortic balloon counterpulsation or ventricular-assist device before arrival in the anaesthetic room; • acute renal failure (anuria or oliguria <10 ml/h).
LV function or LVEF –
• good (LVEF 51% or more);
• moderate (LVEF 31–50%);
• poor (LVEF 21–30%);
• very poor (LVEF 20% or less).
Urgency of procedure -
• Elective: routine admission for operation; • Urgent: patients not electively admitted for operation but who require surgery on the current admission for medical reasons and cannot be discharged without a definitive procedure; • Emergency: operation before the beginning of the next working day after decision to operate;
Salvage: patients requiring cardiopulmonary resuscitation (external cardiac massage) en route to the operating theatre or before induction of anaesthesia. This does not include cardiopulmonary resuscitation after induction of anaesthesia.
Recent MI - Within 90 days before operation.
Weight of procedure - This measures the extent or size of the intervention. The baseline is isolated CABG: operations ‘heavier’ than the baseline are in three categories:
• Isolated non-CABG major procedure (e.g. single valve procedure, replacement of ascending aorta, correction of septal defect, etc.);
• Two major procedures (e.g. CABG+AVR), or CABG+mitral valve repair (MVR), or AVR+replacement of ascending aorta, or CABG+maze procedure, or AVR+MVR, etc.);
• Three major procedures or more (e.g. AVR+MVR+CABG, or MVR+CABG+tricuspid annuloplasty, etc.), or aortic root replacement when it includes AVR or repair+coronary reimplantation+root and ascending replacement).
Only major cardiac procedures count towards to the total.
Examples of procedures which do not qualify are: sternotomy, closure of sternum, myocardial biopsy, insertion of intra-aortic balloon, pacing wires, closure of aortotomy, closure of atriotomy; removal of atrial appendage, coronary endarterectomy as part of CABG, etc.
Brain natriuretic peptide BNP is an independent predictor of cardiac surgical outcome but only 7.3% data was available.Hence, due to poor availability of data it is not included in the model although it may be useful in the future.