SCORING SYSTEMS : CARDIAC RISK ASSESSMENT

Scoring systems: Cardiac Risk Assessment

 

Paiement et al 1983 at Montreal Heart Institute - 

 

8 Risk Factors -

1. Poor LV function
2. CHF
3. Unstable angina or recent MI (within 6 weeks)
4. Age>65 years
5. Severe obesity BMI >30 kg/m2
6. Reoperation
7. Emergency surgery
8. Other significant or uncontrolled systemic disturbances

 

 Parsonnet scoring system (14 risk factors) -

 

Components of additive model

Sr no.	Risk factors	Assigned weight
1	Female sex	1
2	Morbid obesity	3
3	Diabetes (unspecified type)	3
4	HTN SBP>140 mmHg	0
5	LVEF good>50          Fair 30-49          Poor <30	0  2  4
6	Age 70-74         75-79         >80	7  12  20
7	Reoperation first                      Second	5  10
8	Pre operative IABP	2
9	LV aneurysm	5
10	Emergency surgery after PTCA or cardiac catheterisation	10
11	Dialysis dependent(PD/Hemo)	10
12	Catastrophic States Acute structural defects Cardiogenic shock Acute renal failure	10-50
13	Other rare circumstances Paraplegia Pacemaker dependency Congenital HD in adults Severe asthma	2-10
14	Valve surgery Mitral PAP >60 mmHg Aortic PG >120 mmHg CABG at the time of valve surgery	5  8  5  7  2

 

Bernstein and Parsonnet -

 

Simplified the risk adjusted score in 2000

They developed a logistic regression model in which 47 potential risk factors were considered

In this method only simple addition and graphic interpretation is done to see the estimated risk

 

O’Connor et al -

 

Regression model 3055 patients in 1987-89

They proposed independent predictors of in-hospital mortality like

1. Age
2. BSA
3. Co morbidity score
4. Prior CABG
5. EF
6. LVEDP
7. Priority of surgery

 

Higgins et al -

 

• Clinical severity score for CABG
• Cleveland clinic
• Multivariate logistic regression model to predict peri-op risk
• 5051 patients 1986-88

 

Independent predictors-

In hospital and 30 day mortality were

1. Emergency operations
2. Pre-op Sr.Cr >168 mol/lit
3. Severe LV dysfunction
4. Pre-op haematocrit <34%
5. Increasing age
6. Chronic pulmonary disease
7. Prior vascular surgery
8. Re operation
9. MV insufficiency

 

Predictors of morbidity -

1. DM
2. Wt >65 kgs
3. AS
4. Cerebrovascular disease

Each independent predictor was assigned a weight or score- increasing mortality with increasing score

 

New York State model of Hannan et al -

Mortality definition was “in-hospital “

Only CABG isolated

 

Cardiac Anaesthesia Risk Evaluation Score -

 

1. Patient with stable cardiac disease and no other medical problem.A non complex surgery is undertaken
2. Patient with stable cardiac disease and one or more controlled medical problem. A non complex surgery is undertaken
3. Patient with any uncontrolled medical problem or patient in whom a complex surgery is undertaken
4. Patient with any uncontrolled medical problem and in whom a complex surgery is undertaken
5. Patient with chronic or advanced cardiac disease for whom cardiac surgery is undertaken as a last hope to save or improve life.

E- Emergency –surgery as soon as diagnosis is made and OR is available.

 

Society of Thoracic Surgeons STS -

 

STS NCD – National cardiac database is largest in the world

Established in 1989

Includes 892 participating hospitals in 2008

It evaluates 51 preoperative variables on operative mortality

A standard logistic regression analysis is done to form risk model

 

The preoperative risk factors associated with greatest operative mortality rates are -

       Salvage status

       Renal failure

       Emergency status

       Multiple reoperations

       NYHA class 4

 

3 general STS risk models are –

       CABG

       Valve surgery

       Valve surgery with CABG

 

These apply to 7 specific procedures -

Valve model = Isolated AVR, Isolated MVR, MV repair

Valve + CABG = AVR + CABG, MVR + CABG, MV repair + CABG

CABG model = Isolated CABG

 

Besides operative mortality 8 additional end-points are developed -

1. Re-operation
2. Permanent stroke
3. Renal failure
4. Deep sternal wound infection
5. Prolonged ventilation >24 hours
6. Major morbidity
7. Operative death
8. Short < 6 days & > 14 days postoperative length of stay

 

The calibration of risk factors is based on observed/expected O/E ratio.The expected mortality (E) is calibrated to obtain the national E/O ratio.

 

Risk Model Variables STS – 1996 CABG 2 risk model

1. Age
2. Female sex
3. Non-White
4. Ejection fraction
5. Diabetes Mellitus
6. Renal failure
7. Serum creatinine (if renal failure is present)
8. Dialysis (if renal failure is present)
9. Pulmonary hypertension
10. Cerebrovascular accident timing
11. Chronic obstructive airway disease
12. Peripheral vascular Disease
13. Cerebrovascular disease
14. Acute evolving, extending MI
15. MI timing
16. Cardiogenic shock
17. Use of diuretics
18. Haemodynamic instability
19. TVD
20. LM >50%
21. Pre-op IABP
22. Status- urgent/emergent, emergent salvage
23. First operation
24. Multiple re-operations
25. Arrhythmias
26. BSA
27. Obesity
28. NYHA class IV
29. Use of steroids
30. CHF
31. PTCA within 6 hrs of surgery
32. Angiographic accident with haemodynamic instability
33. Use of digitalis
34. Use of IV nitrates

 

Euroscore -

 

European System For Cardiac Operative Risk Evaluation

19030 patients

128 centres across Europe

Following risk factors were associated

Age, female sex, sr.creatinine, extracardiac arteriopathy, chronic airway disease,severe neurologic dysfunction, previous cardiac surgery, recent MI, LVEF, chronic CHF, plump nary hypertension, acute endocarditis, unstable angina, procedure urgency, critical pre-operative condition, ventricular septal rupture, non-coronary surgery and thoracic aorta surgery.

 

Euroscore is well established in CABG and isolated valve procedures.

It's predictive ability in combined CABG and valve is less studied. For this logistic euroscore is better.

 

Risk factors -

 

Patient related factors -

Sr no.		Definition	Score
1	Age	Per 5 yrs or part there of over 60 yrs	1
2	Sex	Female	1
3	Chronic plum.disease	Long term use of bronchodilators or steroids for lung disease	1
4	Extracardiac arteriopathy	Any 1 or more- Claudication, carotid occlusion or > 50% stenosis, previous or planned intervention abdominal aorta, limb arteries or carotids	2
5	Neurologic dysfunction	Disease severely affecting ambulation or day to day functioning	2
6	Previous cardiac surgery	Requiring opening of pericardium	3
7	Serum creatinine	>200 mol/l before suregry	2
8	Active endocarditis	Patient still under antibiotic treatment at the time of surgery	3
9	Critical pre-op state	Any 1 of the following- VT or VF or aborted sudden death, pre-op cardiac massage, pre-op ventilation before arrival in anaesthesia room, pre-op inotropic support, IABP or pre-op ARF (anuria or oliguria <10 ml/hr)	3

 

 

 

 

 

Cardiac related factors -

 

Sr. No.		Definition	Score
1	Unstable angina	Rest angina requiring IV nitrates until arrival in anaesthesia room	2
2	LV dysfunction	Mod or LVEF 30-50% Poor or LVEF >30% Recent MI (within 90 days	1  2  3
3	Pulmonary hypertension	SPAP >60mmHg	2

 

Surgery related factors -

 

Sr. No.		Definiton	Score
1	Emergency	Carried out on referral before beginning of next working day	2
2	Other than isolated CABG	Major cardiac procedure other than or in addition to CABG	2
3	Surgery on thoracic aorta	For disorder of ascending aorta,arch or descending aorta	3
4	Post MI septal rupture		4

Application of euroscore scoring system

Low risk         0-2

Medium risk  3-5

High risk.       6 plus

 

EUROSCORE II - DISCUSSED IN DETAIL IN  HIGHLIGHT SECTION

 

 

 

 

 

 

 

- by Dr Amarja