Patient selection: cardiac surgery
Outcome: postoperative atrial fibrillation
Parameters:
(1) age in years
(2) COPD
(3) renal status (eGFR in mL per min per 1.73 square meter or dialysis)
(4) emergency surgery
(5) preoperative intra-aortic balloon pump (IABP)
(6) left ventricular ejection fraction in percent
(7) valve surgery
|
Parameter
|
Finding
|
Beta-Coefficient
|
Points
|
|
age in years
|
< 60 years
|
0
|
0
|
|
|
60 to 69 years
|
0.715
|
1
|
|
|
70 to 79 years
|
1.076
|
2
|
|
|
>= 80 years
|
1.372
|
3
|
|
COPD
|
absent
|
0
|
0
|
|
|
present
|
0.286
|
1
|
|
renal status
|
eGFR >= 15 and no dialysis
|
0
|
0
|
|
|
eGFR < 15 or dialysis
|
0.643
|
1
|
|
emergency surgery
|
no
|
0
|
0
|
|
|
yes
|
0.404
|
1
|
|
preoperative IABP
|
no
|
0
|
0
|
|
|
yes
|
0.644
|
1
|
|
LVEF
|
>= 30%
|
0
|
0
|
|
|
< 30%
|
0.369
|
1
|
|
valve surgery
|
no
|
0
|
0
|
|
|
yes
|
0.519
|
1
|
X =
= SUM(points for all 7 beta-coefficients) - 2.032
probability of postoperative atrial fibrillation =
= 1 / (1 + EXP((-1) * X))
total point score =
= SUM(points assigned to all 7 parameters)
Interpretation:
• minimum point score: 0
• maximum point score: 9
• The higher the point score the greater the chances of postoperative atrial fibrillation.
|
Total Score
|
Postoperative AF
|
|
0
|
11-13%
|
|
1
|
20%
|
|
2
|
29-30%
|
|
3 to 9
|
41-42%
|
If the data in Figure is evaluated the line equation is:
probability =
= (0.388 * ((score)^2)) + (7.084 * (score)) + 12.17
Performance:
• The area under the ROC curve was 0.65 in the derivation cohort.
