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CORONARYRISKSCORING

DR. S. KARTHICK PRABHU

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WHY

Clinical, non-invasive & invasive tools are useful in refiningthe estimate of risk for the individual pt with angina.

Non-invasively acquired information is valuable in identifyingthe candidates for cardiac catheterization.

Risk scoring is an instrument to assess both the relative risk& absolute risk of developing CV disease & mortality in an

individual.

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RISK SCORING

There are different methods of risk scoring

-Some use mathematical model,others use charts orcomputer programmes.

Few methods are

1. TIMI risk scoring

2. Framingham risk scoring

3. GRACE- Global Registry of Acute Coronary Events

4. Joint British chart

5. The New Zealand chart

6. The Sheffield tables

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TIMI Risk scoring

Have 7 independent risk factors

-Age, >65y

-At least 3 risk factors for CAD :( like f/h of

CAD,SHT,dyslipidemia,DM,or current smoker)

-Signi coronary stenosis : (eg, prior coronary stenosis >50%)

-ST deviation >0.5mm

- >2 anginal events in last 24h-Use of aspirin in last 7days

-Elevated S.Cardiac markers

Total possible points are 14.

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TIMI

Use of this scoring system was able to risk-stratify patientsacross a 10 fold gradient of risk.

Predicts the response to the therapies in UA / NSTEMI.

Patients with higher TIMI risk scores signi reductions inevents when treated with enoxaparin~unfractionatedheparin, GP IIb/IIIa inhibitor~placebo & invasive vsconservative strategy.

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FRAMINGHAM RISK SCORING

Risk scoring- essential for planning the line of management.

This is the 1st such method-took 6 variables to predict the 10 & 20yrisk of CAD.

This algorithm provides estimates of total CHD risk (developingeither angina, MI or coronary disease death) over 10 yrs.

Relative risk for CHD is estimated by comparison to low riskparticipants.

Separate score sheets are used for men & women.

Factors used to estimate risk include age , T.cholesterol, HDL, BP,smoking, & DM.

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FRAMINGHAM-sample score sheet Consider a 55y old man, T.ch-250mg%, HDL-39mg%, BP-146/88,

DM+, & non-smoker.

1 Age - 55y 4

2 T. Cholesterol -250mg% 2

3 HDL - 39mg% 1

4 BP - 146/88mm Hg 2

5 DM - yes 2

6 Cig smoker no 0

Total point 11

Estimated 10y CHD Risk 31%Low 10y CHD Risk 7%

Relative risk 31/7 = 4.4

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FRAMINGHAM Cont

Low risk derived by using

persons of the same age, optimalBP, T.cho-160-199, HDL- 45 for men or 55 for

women, non-smoker & no DM.

Relative risk 4.4, means that coronary riskfor this person is approximately 4 times thatof a man the same age with a low risk profile.

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FRAMINGHAM cont

Limitations :

-Only for persons without heart disease.

-Study population is almost all Caucasian.-Estimates the risk of developing CHD within a 10y

time.

For the Indians, the cut-off point for cholesterol level, wt,waist-hip ratio underestimate the risk of CHD.

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GLOBAL REGISTRY OF AC. CORONARYEVENTS

Collects clinical data in pts with UA / NSTEMI / STEMI,from 245 hospitals in 30 countries on current practices ofcare provided .

GRACE risk model identified factors associatedindependently with increased mortality were increased age,

Killip class, increased HR, lower SBP, ST segment deviation,cardiac arrest at presentation, & elevated S.creatinine orcardiac enzymes.

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Joint British chart/New Zealand/Sheffieldtable All included factors are age, sex, smoking, DM status, BP, & ratio of

T.cholesterol to HDL as part of their risk assessment.

Isles et al (BMJ july 2000)- studied all 3 & compared them .

Sensitivity & specificity of Sheffield & Jt British are nearer &

that of NZ are least.

Jt British chart not appropriate for pts with established CAD,familial hyperlipidemia, CKD or DM.

Sheffield 98% 91%

Joint British 91% 98%

New Zealand 83% 89%

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REYNOLDS RISK SCORE

Provides a greater accuracy for assessment ofcardiovascular risk in women.

-Other alternative scoring systems areThe Heart score, Prospective cardiovascular

Munster study, etc.

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Conclusion

Most of the risk scoring algorithms focus on 5y or 10yabsolute risks for developing CHD, which is helpful in a high

risk individual.

It is also essential to identify the long-term risks, becauseeven a single elevated risk factor can lead to signi risks for

CHD in future.

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