Risk score for predicting abdominal complications after coronary artery bypass grafting

Table 1 Indicators for the evaluation of the risk factors for abdominal complications

Factor	Indicator	Mean (95%CI) or n (%)
Male sex	1–Presence/0-Absence	5164 (78.4)
Age in years	Number	61 (56 to 66)
Weight, kg	Number	82 (73 to 93)
Height, cm	Number	169 (161 to 174)
Body mass index, kg/m2	Number	29.27 (26.35 to 32.56)
Left ventricular ejection fraction, %	Number	55.69 (47.74 to 61)
Post-infarction cardiosclerosis	1–Presence/0-Absence	4429 (67.2)
Cerebrovascular accident in the anamnesis	1–Presence/0-Absence	359 (5.5)
Chronic kidney disease	1–Presence/0-Absence	917 (13.9)
Multifocal atherosclerosis	1–Presence/0-Absence	673 (10.2)
Diabetes	1–Presence/0-Absence	1452 (22)
The duration of cardiopulmonary bypass in min	Number	77 (60 to 107)
Aortic clamping time in min	Number	41 (31 to 61)
Combination of coronary artery bypass grafting with valve correction	1–Presence/0-Absence	1049 (15.9)
Resternotomy	1–Presence/0-Absence	294 (4.5)
Postoperative bleeding requiring resternotomy	1–Presence/0-Absence	182 (2.8)
Other reasons for resternotomy	1–Presence/0-Absence	100 (1.52)
Atrial fibrillation in the postoperative period	1–Presence/0-Absence	695 (10.6)
Intra- and postoperative myocardial infarction	1–Presence/0-Absence	90 (1.37)
Intra- and postoperative cerebrovascular accident	1–Presence/0-Absence	74 (1.12)
Intra-aortic balloon pump	1–Presence/0-Absence	13 (0.19)
Extracorporeal membrane oxygenation	1–Presence/0-Absence	30 (0.45)

CI: Confidence interval.

Table 2 Qualitative risk factors of abdominal complications and relative risk of abdominal complications

Factor	Patients with the presence of a studied factor		Patients with the absence of a studied factor		Relative risk	Р value
	n	Risk of abdominal complications, n (%)	n	Risk of abdominal complications, n (%)
Extracorporeal membrane oxygenation	30	11 (36.67)	6556	62 (0.95)	38.7	< 0.001
Intra-aortic balloon pump	13	4 (30.77)	6573	69 (1.05)	29.3	< 0.001
Perioperative myocardial infarction	90	17 (18.89)	6496	56 (0.86)	21.9	< 0.001
Resternotomy	294	29 (9.86)	6292	44 (0.7)	14.1	< 0.001
Cerebrovascular accident in the perioperative period	74	7 (9.46)	6512	65 (1.0)	9.4	< 0.001
Atrial fibrillation in the postoperative period	695	36 (5.18)	5891	37 (0.63)	8.2	< 0.001
Multifocal atherosclerosis	673	23 (3.42)	5913	50 (0.85)	4.0	< 0.001
Combination of coronary artery bypass grafting with valve correction	1049	29 (2.76)	5537	44 (0.79)	3.4	< 0.001
Cardiopulmonary bypass with the duration of more than 125 min	1238	31 (2.5)	5348	42 (0.79)	3.19	< 0.001
Aortic clamping time of more than 70 min	1374	29 (2.11)	5212	44 (0.84)	2.5	< 0.001
Age over 70 yr	830	18 (2.17)	5756	55 (0.96)	2.3	0.0018
Cerebrovascular accident in the anamnesis	359	8 (2.23)	6227	65 (1.04)	2.1	0.037
Chronic kidney disease	917	14 (1.53)	5669	59 (1.04)	1.4	0.19
Male sex	5164	60 (1.16)	1422	13 (0.91)	1.3	0.43
Postinfarction cardiosclerosis	4429	48 (1.08)	2157	25 (1.16)	0.94	0.78
Diabetes	1452	10 (0.69)	5134	63 (1.23)	0.56	0.084

Table 3 Coefficients of the model of multivariate logistic regression (Nagelkerke R Square = 0.966, Р < 0.0001)

Risk factor	B ± SE	Exp (B)	P value
Multifocal atherosclerosis	0.74 ± 0.28	2.10	0.001
Extracorporeal membrane oxygenation	2.323 ± 0.546	10.207	< 0.001
Intra-aortic balloon pump	1.762 ± 0.887	5.824	0.047
Resternotomy	1.922 ± 0.316	6.833	< 0.001
Atrial fibrillation in the postoperative period	1.62 ± 0.262	5.054	< 0.001
Perioperative myocardial infarction	1.384 ± 0.415	3.991	0.001
Constant	5.508 ± 0.193	0.004	< 0.001

B: Coefficient of regression; SE: Standard error.

Table 4 Distribution of scores assigned to the risk factors for abdominal complications

Risk factor	Score
Multifocal atherosclerosis	3
Extracorporeal membrane oxygenation	10
Intra-aortic balloon pump	6
Atrial fibrillation in the postoperative period	5
Perioperative myocardial infarction	4
The need to perform postoperative resternotomy (excluding patients with extracorporeal membrane oxygenation)	7

Table 5 Results of receiver operating characteristic curve analysis

Factor	AUC	SE (AUC)	95%CI	P value
The exact predicted probability	0.805	0.033	0.739-0.869	< 0.001
Total score	0.805	0.033	0.740-0.871	< 0.001

AUC: Area under the curve; CI: Confidence interval; SE: Standard error.

Table 6 Distribution of patients according to the risk groups of abdominal complications after coronary artery bypass grafting with cardiopulmonary bypass

Risk group	Score	Risk of abdominal complications, %	n	The percentage of the risk group in the general population, %
Low risk of abdominal complications	0	0.4	5072	77.0
Moderate risk of abdominal complications	1-6	1.2	1047	15.9
High risk of abdominal complications	7-12	9.4	421	6.4
Very high risk of abdominal complications	≥ 13	44	46	0.7