A modification of the prognostic index of Peel et al (1962) can be used to assess the severity of myocardial infarction in patients. This can be used to compare outcomes for different treatment modalities. The differences from the original index include addition of serum enzyme data, simplification of heart failure and changes in description of shock.
|
Parameter |
Finding |
Severity Score |
|---|---|---|
|
age and sex |
male < 55 years old |
0 |
|
|
male 55-59 years old |
1 |
|
|
male 60-64 years |
2 |
|
|
male >= 65 years |
3 |
|
|
female < 65 years old |
2 |
|
|
female >= 65 years old |
3 |
|
past history |
previous myocardial infarction |
6 |
|
|
exertional dyspnea (or) significant cardiovascular disease |
3 |
|
|
angina only |
1 |
|
|
no history of cardiovascular disease |
0 |
|
shock |
blood pressure >= 100 mm Hg |
0 |
|
|
blood pressure < 100 mm Hg |
4 |
|
|
blood pressure < 100 mm Hg and cold extremities |
7 |
|
heart failure |
not breathless |
0 |
|
|
breathless |
4 |
|
electrocardiogram |
normal |
0 |
|
|
normal QRS with abnormalities in ST and/or T waves |
1 |
|
|
QR complexes |
3 |
|
|
QS complexes (or) bundle branch block |
4 |
|
rhythm |
sinus |
0 |
|
|
atrial fibrillation (or) atrial flutter (or) PAT (or) sinus tachycardia > 110 beats per minute (or) frequent ectopics (or) nodal rhythm (or) block |
4 |
|
aspartate aminotransferase (AST) |
normal |
0 |
|
|
1-5 times normal |
1 |
|
|
> 5 times normal |
4 |
where:
• The electrocardiogram evaluation is based on the first ECG.
• The serum AST level is based on the initial determination.
modified prognostic index =
= (score for age and gender) + (score for past history) + (score for shock) + (score for heart failure) + (score for ECG) + (score for rhythm)+ (score for AST)
Interpretation:
• minimum score 0
• maximum score 32
|
Score |
Mortality Rate |
|---|---|
|
<= 5 |
6% |
|
6 – 7 |
9% |
|
8 – 9 |
12% |
|
10 – 11 |
14% |
|
12 – 13 |
17% |
|
14 – 16 |
20% |
|
>= 17 |
23% |
Limitation:
The upper end point in mortality rate data only goes to scores of 17 or above, although the maximum score can reach 32. For scores above 20, the mortality rate would be expected to be higher than 23%. If the data is compared with that of Peel (1962), the mortality rate:
(1) is slightly higher at low scores
(2) is comparable in the midrange
(3) is lower at the upper end (for score of 17, a rate of 53% in the original vs 23% in the modified).
The difference at the upper end can be explained by the addition of the AST data (shift scores at least 1 point higher), plus paucity of mortality data for scores over 20 in the modified index.
Purpose: To use a modification of the myocardial infarction index proposed by Peel et al to assess the severity of a myocardial infarct.
Specialty: Cardiology
Objective: severity, prognosis, stage, selection
ICD-10: I21,
