Soslow et al developed a clinical prediction model to predict the risk of coarctation of the aorta in a neonate with patent ductus arteriosus. The authors are from Vanderbilt University.
Patient selection: neonate with PDA
Parameters:
(1) diameter of the distal transverse arch diameter
(2) distance from the left carotid to left subclavian arteries in cm
(3) diameter of the aortic isthmus in cm
(4) diameter of the descending aorta in cm
(5) diameter of the carotid artery in cm
CSA ratio =
= (diameter of the distal transverse arch) / (distance from the left carotid to left subclavian)
I/D ratio=
= (diameter of the aortic isthmus) / (diameter of the descending aorta)
CA/DT ratio =
= (diameter of the carotid artery) / (diameter of the distal transverse arch)
X =
= (12.5 * (CA/DT ratio)) - (9.8 * (I/D ratio)) - (0.601 * (CSA ratio)) - 2.02
probability of coarctation =
= 1 / (1 + EXP((-1) *X))
For the nomogram:
points for CSA ratio =
= 24 - (4.8 * (ratio)) over range from 0 to 5
points for I/D ratio =
= 78.5714 - (78.5714 * (ratio)) over range from 0.3 to 1
points for CA/DT ratio =
= (100 * (ratio)) - 50 over range from 0.5 to 1.5
total score =
= SUM(points for all 3 parameters)
|
Total Score
|
Probability of Coarctation
|
|
< 32
|
< 1%
|
|
32 to 105
|
Y= (0.126 * (score)) - 8.647;
probability = 1/(1+EXP((-1)*Y))
|
|
> 105
|
> 99%
|
