### Description

Woo developed a coronary prognostic index (CPI) to predict the prognosis for a person of Chinese descent who has had an acute myocardial infarction. This can help identify patients who may require more aggressive therapy. The author is from the Chinese University of Hong Kong.

Parameters:

(1) age

(2) systolic blood pressure

(3) heart size on chest X-ray (CTR, or cardiothoracic ratio)

(4) lung fields on chest X-ray

(5) serum urea

(6) cardiac arrhythmias

(7) infarct position

where:

• The cardiothoracic ratio (CTR) is measured from a AP chest X-ray. It is the ratio of (a) widest transverse diameter of the heart in cm, and (b) the internal transverse diameter of the chest measured at the level of the highest point on the left hemidiaphragm.

Each parameter has an associated score based on the product of an "x" and "y" value.

Parameter

Y Value

age

2.1

systolic blood pressure

2.5

heart size

0.1

lung fields

0.7

serum urea

2.5

cardiac arrhythmias

1.2

infarct position

3.8

Parameter

Finding

X Value

age

<= 59 years

0.3

60 – 69 years

0.5

>= 70 years

1

systolic blood pressure

>= 90 mm Hg

0

< 90 mm Hg

1

heart size (CTR)

<= 55%

0

> 55%

1

lung fields

normal

0

congested and/or edema

1

serum urea

<= 10 mmol/L

0

> 10 mmol/L

1

cardiac arrhythmias

absent

0

present

1

infarct position

non Q-wave

0.2

posterior

0.4

LBBB

0.4

anterior

0.6

anterior and RBBB

1

anterior and posterior

1

CPI =

= SUM((x * y) for each parameter)

Interpretation:

• minimum score: 1.39

• maximum score: 12.9

• The higher the score, the more serious the infarct.

• A high score reflects both the extent of the infarct and the number of organ failures present.

• For the implementation I rounded the CPI before reading the mortality rate from the table.

CPI

Mortality Rate
(Hong Kong 1971-1980)

< 2

1.6%

2 – 3

6.2%

4 – 5

21.4%

6 – 7

53.9%

8 – 9

69.7%

10 – 11

78.9%

> 12

100%

from Table 4, page 565

Limitations:

• The index was developed in 1987 and may not reflect the impact of newer diagnostic and therapeutic interventions.

• The index was developed in Chinese patients in a Chinese cultural setting. It may not correlate the same in persons of Chinese descent in North America or Europe eating a Western diet.