Preoperative and intraoperative variables
Preoperative and intraoperative variables are shown in Table 1. BMI was significantly greater in Group A (Group A vs. Group B: 24.0 (3.33) vs. 23.2 (3.58), p = 0.031). The LVEF was significantly greater in Group A (Group A vs. Group B: LVEF: 65.0 [59.0;68.0] vs. 63.0 [56.6;68.0], p = 0.045). Among the preoperative factors, 2 groups showed no significant differences in demographic characteristics (age, gender, etc.), myocardial performance status (LV ejection fraction, troponin) or comorbidities (hypertension, hyperlipidemia, COPD, diabetes) after PSM.
The duration of the ACC (aortic cross clamp) was significantly greater in Group A (Group A vs. Group B: 157 (41.1) vs. 142 (40.0), p = 0.001). We found a statistically significant difference in CPB (cardiopulmonary bypass) (Group A vs. Group B: 117 (37.3) vs. 107 (33.4), p = 0.011), with Group A being significantly longer. There was no significant difference in ACC time after PSM (Group A vs. Group B: ACC time: 113 (30.2) vs. 107 (33.2), p = 0.125). There were no significant differences in the use of electric defibrillation between the 2 groups.
Table 1
Preoperative and intraoperative variables
|
|
Unmatched
|
|
|
Matched
|
|
|
|
All cases
N = 340
|
Group A
<=30 n = 164
|
Group B
> 30 n = 176
|
P
|
Group A
<=30 n = 125
|
Group B
> 30 n = 125
|
P
|
Female (%)
|
165 (48.5)
|
84 (51.2)
|
81 (46.0)
|
0.396
|
61 (48.8)
|
57 (45.6)
|
0.704
|
Male (%)
|
175 (51.5)
|
80 (48.8)
|
95 (54.0)
|
64 (51.2)
|
68 (54.4)
|
|
Age
|
58.3 (12.1)
|
59.0 (11.7)
|
57.7(12.5)
|
0.315
|
58.2 (11.9)
|
57.3(12.1)
|
0.571
|
Height (cm)
|
163 (8.45)
|
163 (8.86)
|
162 (8.07)
|
0.823
|
164 (8.57)
|
162 (7.90)
|
0.270
|
Weight (kg)
|
62.5 (11.2)
|
63.7 (10.6)
|
61.5 (11.6)
|
0.063
|
63.6 (10.5)
|
61.8(11.3)
|
0.178
|
BMI(kg/m^2)
|
23.6 (3.48)
|
24.0 (3.33)
|
23.2 (3.58)
|
0.031
|
23.7 (3.08)
|
23.4(3.46)
|
0.393
|
BSA (m^2)
|
1.64 (0.18)
|
1.65 (0.17)
|
1.63 (0.18)
|
0.128
|
1.66 (0.17)
|
1.63(0.18)
|
0.187
|
Diabetes (%)
|
42 (12.4)
|
17 (10.4)
|
25 (14.3)
|
0.352
|
10 (8.00)
|
17 (13.6)
|
0.221
|
Hypertension (%)
|
126 (37.2)
|
61 (37.2)
|
65 (37.1)
|
1.000
|
49 (39.2)
|
49 (39.2)
|
1.000
|
Hyperlipidemia (%)
|
117(34.5)
|
55 (33.5)
|
62 (35.4)
|
0.801
|
40 (32.0)
|
46 (36.8)
|
0.506
|
COPD (%)
|
4(1.18)
|
1 (0.61)
|
3(1.7)
|
0.624
|
1 (0.80)
|
2 (1.60)
|
1.000
|
LVEF (%)
|
64.0 [57.8;68.0]
|
65.0 [59.0;68.0]
|
63.0 [56.6;68.0]
|
0.045
|
64.7 [59.0;67.0]
|
64.4 [59.8;68.1]
|
0.544
|
CKMB(U/L)
|
11[8.0;14.0]
|
11.[8.0;14.0]
|
10.[8.0;14.]
|
0.579
|
11.[9.0;13]
|
11.[8.0;14]
|
0.745
|
CKMB mass (ng/ml)
|
1.53 [0.96;3.02]
|
1.58 [0.83;2.78]
|
1.38 [1.14;3.07]
|
0.924
|
1.48 [1.00;1.55]
|
1.27 [1.16;1.28]
|
0.445
|
hs-cTnI (ng/L)
|
0.01 [0.00;0.01]
|
0.00 [0.00;0.01]
|
0.01 [0.00;0.01]
|
0.063
|
0.00 [0.00;0.01]
|
0.01 [0.00;0.01]
|
0.060
|
hs-cTnt (ug/L)
|
14.8 [8.90;37.7]
|
14.8 [9.28;34.8]
|
14.9 [8.85;44.1]
|
0.885
|
11.7 [9.00;13.1]
|
12.5 [8.90;14.9]
|
0.087
|
Creatinine (umol/L)
|
73[61;89]
|
70[60;84.0]
|
76.[63;92]
|
0.058
|
70.[62;84]
|
76[64;92]
|
0.249
|
Bnp(pg/ml)
|
138 [55.0;272]
|
133 [55.0;240]
|
152 [55;305]
|
0.237
|
122 [49.0;208]
|
166 [56;281]
|
0.146
|
Intraoperative
|
|
|
|
|
|
|
CPB time(min)
|
149 (41.2)
|
157 (41.1)
|
142 (40.0)
|
0.001
|
154 (35.3)
|
142 (40.8)
|
0.017
|
ACC time(min)
|
112 (35.7)
|
117 (37.3)
|
107 (33.4)
|
0.011
|
113 (30.2)
|
107 (33.2)
|
0.125
|
Electric defibrillation (%)
|
278 (81.8)
|
128 (78.0)
|
150 (85.2)
|
0.116
|
99 (79.2%)
|
105(84.0%)
|
0.414
|
Primary endpoints and secondary endpoints
Postoperative variables are shown in Table 2. Primary endpoints, including CK-MB, CK-MB mass-0 h (Group A vs. Group B: 46.1 [34.1;56.0] ng/ml vs 47.0 [36.0;62.7] ng/ml, p = 0.391), CK-MB mass-7 h (Group A vs. Group B: 33.5 [28.0;44.9] ng/ml vs 34.3 [28.7;49.3] ng/ml, p = 0.439), CK-MB mass-24 h (Group A vs. Group B: 25.0 [13.7;28.8] ng/ml vs 20.6 [15.1;31.3] ng/ml, p = 0.670), hs-cTnI (Group A vs. Group B: 5.97 [4.29;9.85] µg/L vs 6.43 [4.08;9.83] µg/L, p = 0.614) and hs-cTnT (Group A vs. Group B: 704 [537;1049] ng/L vs. 765 [464;1334] ng/L, p = 0.982) levels did not show significant differences between two groups. The LV ejection fraction was significantly greater in Group B (Group A vs. Group B: 63.7 [59.9;69.0]% vs 62.9 [54.8;67.4]%; p = 0.034). After PSM, the following levels were significantly greater in Group B: CK-MB mass-0 h (Group A vs. Group: 46.1 [46.1;48.3] ng/ml vs 49.0 [40.0;60.0] ng/ml, p < 0.001) and CK-MB mass-7 h (Group A vs. Group B: 38.2 [32.3;42.2] ng/ml vs 49.9 [46.1;62.7] ng/ml, p = 0.001). The highest level of CK-MB mass was found shortly after surgery in both groups (Fig. 1). LV ejection fraction (Group A vs. Group B: 63.3 [59.4;68.0]% vs. 63.4 [55.5;67.9]%, p = 0.521; Fig. 3), hs-cTnI (Group A vs. Group B: 6.04 [4.50;9.85] µg/L vs. 6.40 [4.08;9.26] µg/L, p = 0.711) and hs-cTnT (Group A vs. Group B: 541 [482;629] ng/L vs. 569 [475;759] ng/L, p = 0.692; Fig. 2) levels did not significantly differ between group A and group B.
Table 2
|
|
Unmatched
|
|
|
Matched
|
|
|
|
All cases
N = 340
|
Group A
<=30 n = 164
|
Group B
> 30 n = 176
|
P
|
Group A
<=30 n = 125
|
Group B
> 30 n = 125
|
P
|
Primary endpoints
|
|
|
|
|
|
|
CKMB 0 U/L
|
65.0 [51.5;81.0]
|
66.0 [54.0;81.0]
|
62.0 [51.0;80.8]
|
0.378
|
67.0 [54.0;86.0]
|
69.0 [55.0;86.0]
|
0.809
|
CKMB > 7h (U/L)
|
48.0 [37.0;59.0]
|
48.0 [37.0;56.0]
|
48.0 [37.5;60.5]
|
0.740
|
47.0 [40.0;59.0]
|
49.0 [40.0;60.0]
|
0.813
|
CKMB > 24 (U/L)
|
39.0 [29.0;50.0]
|
38.0 [29.0;50.0]
|
40.0 [30.0;50.0]
|
0.572
|
37.0 [29.0;51.0]
|
40.0 [30.0;47.0]
|
0.864
|
CKMB mass 0h (ng/ml)
|
46.4 [35.2;60.6]
|
46.1 [34.1;56.8]
|
47.0 [36.0;62.7]
|
0.391
|
46.1 [46.1;48.3]
|
49.9 [46.1;62.7]
|
<0.001
|
CKMB mass 7h (ng/ml)
|
34.2 [28.3;47.6]
|
33.5 [28.0;44.9]
|
34.3 [28.7;49.3]
|
0.439
|
38.2 [32.3;42.2]
|
42.2 [32.6;49.3]
|
0.001
|
CKMB mass 24h (ng/ml)
|
21.1 [14.9;30.0]
|
25.0 [13.7;28.8]
|
20.6 [15.1;31.3]
|
0.670
|
25.2 [18.0;26.1]
|
20.6 [17.4;26.1]
|
0.101
|
LVEF24h (%)
|
63.3 [57.9;67.9]
|
63.7 [59.9;69.0]
|
62.9 [54.8;67.4]
|
0.034
|
63.3 [59.4;68.0]
|
63.4 [55.5;67.9]
|
0.521
|
hs-cTnT 24h (ng/L)
|
718 [474;1245]
|
704 [537;1049]
|
765 [464;1334]
|
0.982
|
541 [482;629]
|
569 [475;759]
|
0.692
|
Hs-cTnI 24h (ug/L)
|
6.12 [4.22;9.85]
|
5.97 [4.29;9.85]
|
6.43 [4.08;9.83]
|
0.614
|
6.04 [4.50;9.85]
|
6.40 [4.08;9.26]
|
0.711
|
Secondary endpoints
|
|
|
|
|
|
|
Bnp 48h (pg/ml)
|
298 [190;528]
|
278 [168;487]
|
319 [205;599]
|
0.073
|
274 [177;398]
|
311 [202;508]
|
0.118
|
Creatinine 24h(umol/L)
|
80.0 [65.0;104]
|
80.0 [65.5;100]
|
80.0 [63.2;108]
|
0.887
|
82.0 [68.0;101]
|
81.0 [63.0;108]
|
0.553
|
ICU length (hour)
|
90.0 [66.0;122]
|
90.0 [66.0;128]
|
89.0 [64.0;121]
|
0.739
|
90.0 [66.0;135]
|
89.0 [64.0;116]
|
0.762
|
Time in Hospital (day)
|
20.0 [17.0;26.0]
|
20.0 [17.0;25.2]
|
21.0 [17.0;26.0]
|
0.434
|
20.0 [17.0;26.0]
|
20.0 [17.0;24.0]
|
0.600
|
The association of the cardioplegia interval with the postoperative CK-MB mass level.
The relationship between the cardioplegia interval and postoperative CK-MB mass level 0 hour and 7 hours after surgery showed an approximate growth S-curve (Fig. 4). The model fits suggest that the relationship between the interval and the CK-MB mass level is nonlinear. For the level of CK-MB mass at 0 h, the threshold effect analysis suggested that the interval should be longer than 27.6 (95% CI 23.5, 45.5) minutes before it is associated with an increased risk of CK-MB mass level. For the level of CK-MB mass 7 hours after the operation, the threshold effect analysis suggested that an interval greater than 31 (95% Cl 19.8, 43.5) minutes before the operation is associated with an increased risk of CK-MB mass level.
Secondary endpoints
There were no differences between the two groups in terms of ICU length of stay, creatinine levels, or BNP and NT-pro BNP levels.