Description

Morise et al derived a logistic prediction model for the probability of significant coronary artery disease in a patient. The model was adjusted for disease prevalence in the population. The authors are from the West Virginia University, Cedars-Sinai Medical Center, and the Long Beach VA Hospital.


 

Significant coronary artery disease was defined as the presence of 1 or more lesions in the coronary arteries with >= 50% occlusion on angiography

 

Components to model:

(1) pretest probability

(2) post-exercise test probability

 

Parameters for pretest probability:

(1) age

(2) gender

(3) chest pain symptoms

(4) smoking

(5) diabetes mellitus

(6) cholesterol

Parameter

Finding

Points

age in years

 

(age in years)

gender

male

0

 

female

1

chest pain symptoms

no angina pain

1

 

nonanginal pain

2

 

atypical angina

3

 

typical angina

4

current smoking

no

0

 

yes

1

diabetes mellitus

no

0

 

yes

1

cholesterol in mg/dL

 

(cholesterol)

 

If cholesterol data is available:

 

X =

= (0.0894 * (age)) - (1.522 * (points for gender)) + (0.476 * (points for symptoms)) + (0.447 * (points for smoking)) + (0.631 * (points for diabetes)) + (0.004 * (serum cholesterol)) – 7.123

 

If cholesterol data is not available:

 

X =

= (0.101 * (age)) - (1.31 * (points for gender)) + (0.334 * (points for symptoms)) + (0.506 * (points for smoking)) + (0.439 * (points for diabetes)) – 6.14

 

pretest probability of significant coronary artery disease =

= 1 / (1 + EXP((-1)*X))

 

Parameters for post-exercise test probability

(1) pretest probability, as a decimal fraction from 0 to 1.0

(2) ST depression in mm

(3) ST slope

(4) peak heart rate in beats per minute

 

Parameter

Finding

Points

pretest probability

 

(pretest)

ST depression in mm

 

(mm)

ST slope

upsloping

1

 

horizontal

2

 

downsloping

3

peak heart rate in beats/minute

 

(rate)

 

If exercise data is available:

 

Y =

= (4.28 * (pretest probability)) + (0.618 * (mm ST depression)) + (0.475 * (points for ST slope)) – (0.015 * (peak heart rate)) – 1.30

 

If exercise data is not available:

 

Y =

= (4.60 * (pretest probability)) – (0.013 * (peak heart rate)) – 0.319

 

post-exercise probability of significant coronary artery disease =

= 1 / (1 + EXP((-1)*Y))

 


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