Three patients with CRF before surgery and 15 patients who died intraoperatively or within 24 hours after surgery were excluded, a total of 712 patients were included in the study. Among them, 111 cases (15.9%) underwent CRRT after thoracic aortic surgery. For the CRRT group, there were 84 cases (75.7%) of males, the medical history included hypertension in 91 cases (82%), diabetes in 1 case (0.9%), coronary heart disease in 9 cases (8.1%), cardiovascular surgery in 8 cases (7.2%), cerebrovascular accident in 4 cases (3.6%), and pericardial effusion in 13 cases (11.7%). (Table 1) The operation methods included aortic root or ascending aorta replacement in 49 cases (44.1%), total aortic arch replacement in 62 cases (55.9%), and aortic valve treatment in 31 cases (27.9%), coronary artery bypass grafting (CABG) or mitral or tricuspid valve operation in 17 cases (15.3%). 107 patients (96.4%) received emergency operations. The mean CPB duration was 273.4±80.6 minutes, the duration of aortic cross-clamp was 186.0±70.5 minutes, and the mean duration of DHCA was 30.2±50.1 minutes, as shown in Table 2.
Compared with the CRRT group, preoperative age, hypertension, pericardial effusion, preoperative sCr and BUN, intraoperative need for combined CABG or mitral valve or tricuspid valve surgery, CPB time, extracorporeal circulation assistant time, aortic cross-clamp time, drainage volume 24 hours after surgery, ventilator time, 30-day mortality, ICU time between two groups,all above results were higher in CRRT group (P<0.05). There was no significant difference in hospital stay between the two groups. (Table 1,2)
Binary logistic regression analysis showed that preoperative sCr (OR=1.008, 95%CI: 1.002-1.014, P=0.005) and CPB time (OR=1.022, 95%CI: 1.003-1.042, P=0.026) were independent risk factors for CRRT after thoracic aortic surgery. (Table 3)
After propensity scoring, 29 pairs (58 patients) were successfully matched. In these patients, the analysis showed that CPB time was significantly longer in CRRT group (P = 0.004), and the 30-day mortality rate was also higher in this group (44.8% vs 10.3%; P = 0.003). (Table 2)
51 patients in the CRRT group and 43 patients in the control group died during the hospitalization period. At last, a total of 60 CRRT patients and 558 non-CRRT patients were included in the follow-up. The median follow-up time was 29 months. 48 patients were lost from follow-up, including 47 patients in the control group and 1 in the CRRT group. They were excluded from the subsequent long-term survival analysis. There were 41 late deaths, it is important to point out that 1 patient in the control group committed suicide 6 months after discharge and was excluded from the study. Finally, 25 deaths (4.9%) in the control group and 15 (25.4%) in the CRRT group were identified (P<0.001). The survival is shown in Fig. 1.
Table 1 Baseline clinical characteristics of patient population and aortic dissection features before and after propensity score matching
|
|
Before Matching
|
After Matching
|
Characteristics
|
Control(n=601)
|
CRRT(n=111)
|
P Value
|
Control(n=29)
|
CRRT(n=29)
|
P Value
|
Patient characteristics
|
|
|
|
|
|
|
Demographics
|
|
|
|
|
|
|
Age (year)
|
52.0±13.0
|
55.4±14.0
|
0.011
|
54.6±13.2
|
54.8±13.2
|
0.937
|
Male (%)
|
438(72.9)
|
84(75.7)
|
0.540
|
20(69.0)
|
23(79.3)
|
0.368
|
BMI (kg/m2)
|
25.2±5.0
|
26.1±5.0
|
0.146
|
25.8±3.4
|
27.0±5.0
|
0.278
|
Medical history
|
|
|
|
|
|
|
Hypertension (%)
|
401(66.7)
|
91(82.0)
|
0.001
|
20(69.0)
|
21(72.4)
|
0.773
|
Diabetes mellitus (%)
|
11(1.8)
|
1(0.9)
|
0.703
|
0
|
0
|
--
|
Previous cardiac surgery (%)
|
28(4.7)
|
8(7.2)
|
0.260
|
0
|
0
|
--
|
Previous Coronary artery disease (%)
|
18(3.0)
|
9(8.1)
|
0.025
|
1(3.4)
|
2(6.9)
|
1.000
|
Cerebrovascular disease (%)
|
20(3.3)
|
4(3.6)
|
0.779
|
2(6.9)
|
1(3.4)
|
1.000
|
Pericardial effusion (%)
|
15(2.5)
|
13(11.7)
|
<0.001
|
1(3.4)
|
1(3.4)
|
1.000
|
Preoperative laboratory data
|
|
|
|
|
|
|
BUN (mmol/L)
|
7.0±3.8
|
11.5±8.2
|
<0.001
|
7.8±3.0
|
6.6±1.9
|
0.063
|
sCr (μmol/L)
|
91.0±48.4
|
176.0±156.5
|
<0.001
|
96.6±46.7
|
90.1±35.1
|
0.552
|
Aortic dissection features
|
|
|
|
|
|
|
Blood supply of left renal artery (%)
|
|
|
|
|
|
|
True lumen
|
326(64.2)
|
38(62.3)
|
|
14(58.3)
|
6(37.5)
|
|
False lumen
|
133(26.2)
|
17(27.9)
|
|
9(37.5)
|
7(43.8)
|
|
True lumen and false lumen
|
49(9.6)
|
6(9.8)
|
0.978
|
1(4.2)
|
3(18.8)
|
0.272
|
Blood supply of right renal artery (%)
|
|
|
|
|
|
|
True lumen
|
390(76.8)
|
41(67.2)
|
|
18(75.0)
|
11(68.8)
|
|
False lumen
|
91(17.9)
|
13(21.3)
|
|
4(16.7)
|
2(12.5)
|
|
True lumen and false lumen
|
27(5.3)
|
7(11.5)
|
0.106
|
2(8.3)
|
3(18.8)
|
0.766
|
Notes: Data presented as n (%); mean ± standard deviation.
Abbreviations: BMI, body mass index; BUN, blood urea nitrogen; sCr, serum creatinine;
Table 2 Operative data and outcome before and after propensity score matching
|
|
Before Matching
|
After Matching
|
Characteristics
|
Control(n=601)
|
CRRT(n=111)
|
P Value
|
Control(n=29)
|
CRRT(n=29)
|
P Value
|
Operative procedures
|
|
|
|
|
|
|
Total arch replacement (%)
|
309(51.4)
|
62(55.9)
|
0.389
|
16(55.2)
|
20(69.0)
|
0.279
|
CABG/MVR/MVP/TVP (%)
|
51(8.5)
|
17(15.3)
|
0.024
|
5(17.2)
|
4(13.8)
|
1.000
|
Aortic valve (%)
|
185(30.8)
|
31(27.9)
|
0.548
|
9(31.0)
|
7(24.1)
|
0.557
|
CPB-related profiles
|
|
|
|
|
|
|
CPB time (min)
|
235.5±64.1
|
273.4±80.6
|
<0.001
|
236.0±48.8
|
279.3±59.8
|
0.004
|
Extracorporeal circulation assist time (min)
|
54.3±31.0
|
65.9±40.4
|
0.001
|
50.3±30.7
|
60.4±24.5
|
0.174
|
Aortic cross-clamp time (min)
|
165.3±55.1
|
186.0±70.5
|
0.005
|
174.6±48.2
|
191.8±50.9
|
0.192
|
DHCA time (min)
|
28.0±12.7
|
30.2±50.1
|
0.117
|
26.8±10.4
|
31.3±13.9
|
0.173
|
Complications and short-time outcomes
|
|
|
|
|
|
|
Drainage volume 24 hours after surgery (ml)
|
695.0±604.1
|
1091.0±1013.9
|
0.001
|
971.6±1104.1
|
1011.5±681.9
|
0.873
|
Ventilation time (hour)
|
32.0±50.1
|
56.8±61.8
|
0.009
|
37.6±41.6
|
79.9±81.9
|
0.058
|
30-day mortality (%)
|
40(6.7)
|
50(45.0)
|
<0.001
|
3(10.3)
|
13(44.8)
|
0.003
|
ICU Stay time (day)
|
6.5±11.5
|
9.4±6.6
|
0.020
|
5.9±5.7
|
9.3±6.9
|
0.055
|
Hospital stay time (day)
|
22.3±11.6
|
22.5±17.0
|
0.892
|
19.4±10.0
|
21.3±14.3
|
0.560
|
Notes: Data presented as n (%); mean ± standard deviation.
Abbreviations: CABG, coronary artery bypass graft; MVR, mitral valve replacement;
MVP, mitral valvuloplasty; TVP, tricuspid valvuloplasty; CPB, cardiopulmonary bypass; DHCA, deep hypothermic circulatory arrest; ICU, intensive care unit.
Table 3 Binary logistic regression analysis of Risk Factors for the groups with and without Dialysis
Variable
|
Odds Ratio
|
95% CI
|
P value
|
Age
|
1.052
|
0.984-1.052
|
0.312
|
Hypertension
|
2.027
|
0.645-6.376
|
0.227
|
Previous Coronary artery disease
|
0.319
|
0.021-4.866
|
0.412
|
Pericardial effusion
|
0.552
|
0.043-7.051
|
0.647
|
BUN
|
1.041
|
0.966-1.123
|
0.293
|
sCr
|
1.008
|
1.002-1.014
|
0.005
|
CABG/MVR/MVP/TVP
|
0.501
|
0.110-2.279
|
0.371
|
CPB time
|
1.022
|
1.003-1.042
|
0.026
|
Extracorporeal circulation assist time
|
0.997
|
0.980-1.014
|
0.721
|
Aortic cross-clamp time
|
0.987
|
0.967-1.008
|
0.229
|
Drainage volume 24 hours after surgery
|
1.000
|
1.000-1.001
|
0.314
|
Ventilation time
|
1.006
|
0.998-1.014
|
0.131
|
Abbreviations: CI, confidence interval; BUN, blood urea nitrogen; CABG, coronary artery bypass graft;
MVR, mitral valve replacement; MVP, mitral valvuloplasty; TVP, tricuspid valvuloplasty;
CPB, cardiopulmonary bypass.