One hundred patients underwent TAVI during the study period. The TA or transsubclavian approach was used in 16 patients and the TF approach in 84. Three patients who underwent TF-TAVI developed intraoperative complications and were excluded, leaving data for 81 patients available for analysis (see figure, Additional file 1). AKI occurred in 7 (8.6%) of these patients and was categorised as grade 1 in 6 (85.7%) and grade 3 in one (14.3%). No patient required renal replacement therapy. The baseline characteristics of the non-AKI (n=74) and AKI (n=7) groups are shown in Table 1. The mean age was 84.6±5.1 (range, 64–94) years and 72.8% were women. The mean STS score was 6.9%±3.7% and the mean Logistic EuroSCORE was 18.7%±10.9%. There was no significant between-group difference in the frequency of CKD. The preoperative SCr value was significantly higher and the preoperative eGFR was significantly lower in the AKI group than in the non-AKI group (1.32 mg/dl vs 0.87mg/dl, p=0.0232, and 29.5 mL/min/1.73 m2 vs 49.6 mL/min/1.73 m2, p=0.0395, respectively).
Table 1. Baseline characteristics of the study population
|
Non-AKI (n=74)
|
AKI (n=7)
|
p-value
|
Age, years
|
85.5 (82–88)
|
83 (81–86)
|
0.337
|
Male sex
|
19 (25.7%)
|
3 (42.9%)
|
0.382
|
Height, cm
|
147.8 ± 9.8
|
150.0 ± 7.0
|
0.564
|
Body weight, kg
|
48.2 ± 10.2
|
44.3 ± 9.3
|
0.323
|
Hypertension
|
59 (79.7%)
|
6 (85.7%)
|
1.000
|
Hyperlipidaemia
|
41 (55.4%)
|
5 (71.4%)
|
0.693
|
Diabetes mellitus
|
13 (17.6%)
|
2 (28.6%)
|
0.608
|
PAD
|
16 (21.6%)
|
1 (14.3%)
|
1.000
|
CVD
|
18 (24.3%)
|
1 (14.3%)
|
1.000
|
COPD
|
23 (31.1%)
|
3 (42.9%)
|
0.675
|
CABG
|
7 (9.5%)
|
1 (14.3%)
|
0.531
|
PCI
|
12 (16.2%)
|
3 (42.9%)
|
0.114
|
CKD
|
57 (77.0%)
|
6 (85.7%)
|
1.000
|
SCr, mg/dl
|
0.87 (0.72–1.15)
|
1.32 (0.84–1.67)
|
0.023
|
eGFR, mL/min/1.73m2
|
49.6 (37.1–60.0)
|
29.5 (23.2–54.3)
|
0.039
|
EF <40%
|
7 (9.5%)
|
1 (14.3%)
|
0.531
|
Euro SCORE, %
|
16.2 (12.1–22.8)
|
17.4 (8.4–19.2)
|
0.556
|
STS score, %
|
5.7 (4.3–7.6)
|
8.4 (6.6–10.6)
|
0.078
|
*The data are shown as the mean ± standard deviation, number (percentage), or median (interquartile range) as appropriate. AKI, acute kidney injury; CABG, coronary artery bypass grafting; CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; CVD, cerebrovascular disease; EF, ejection fraction; eGFR, estimated glomerular filtration rate; EuroSCORE, European System for Cardiac Operative Risk Evaluation; PAD, peripheral artery disease; STS, Society of Thoracic Surgery
There was no significant between-group difference in operating time, anaesthesia time, intraoperative infusion volume, blood loss, urine volume, transfusion volume, or use of elective percutaneous cardiopulmonary support (Table 2). The CMV was significantly higher in the AKI group than in the non-AKI group (103 ml vs 84 ml, p=0.025), as was the CMV × SCr/BW value (3.34 vs 1.49, p=0.0002).
Table 2. Perioperative findings in the study population
|
Non-AKI (n=74)
|
AKI (n=7)
|
p-value
|
Operating time (min)
|
109 (97–131)
|
121 (108–229)
|
0.135
|
Anaesthesia time (min)
|
242 (226–273)
|
293 (240–339)
|
0.071
|
Intraoperative fluids (ml)
|
1832 (1573–2210)
|
2001 (1612–2312)
|
1.000
|
Bleeding (ml)
|
49 (30–94)
|
60 (40–100)
|
0.584
|
Urine (ml)
|
700 (395–1243)
|
500 (330–800)
|
0.178
|
Transfusion (ml)
|
280 (0–560)
|
280 (280–560)
|
0.085
|
CMV (ml)
|
84 (75–93)
|
103 (85–121.08)
|
0.025
|
CMV × SCr/BW value
|
1.49 (1.25–2.21)
|
3.34 (3.00–4.52)
|
0.0002
|
Fluoroscopy time (min)
|
30.5 (24.7–38.6)
|
30.7 (24.8–89.1)
|
0.602
|
PCPS
|
7 (9.46%)
|
0 (0.0%)
|
1.000
|
*The data are shown as the number (percentage) or median (interquartile range) as appropriate. AKI, acute kidney injury; BW, body weight; CMV, contrast medium volume; PCPS, percutaneous cardiopulmonary support; SCr, serum creatinine
The SCr, eGFR, CMV, and CMV × SCr/BW value were included in the logistic regression analysis. The area under the ROC curve (see figure in Additional file 2) showed that the CMV × SCr/BW value was best able to predict AKI, with an area under the curve of 0.9228 (95% confidence interval 0.650–0.984), a cut-off of 2.99, a sensitivity of 85.7%, and a specificity of 90.4%. The area under the curve for the CMV × SCr/BW value was significantly higher than that for the other variables (Table 3).
Table 3. Comparison of areas under the curve
|
AUC (95% CI)
|
p-value
|
CMV × SCr/BW value
|
0.9228 (0.6757–0.9856)
|
Reference
|
CMV
|
0.7683 (0.5095–0.9137)
|
0.0345
|
SCr
|
0.7606 (0.5205–0.9029)
|
0.0230
|
eGFR
|
0.7375 (0.4383–0.9100)
|
0.0193
|
AUC, area under the curve; BW, body weight; CI, confidence interval; CMV, contrast medium volume; eGFR, estimated glomerular filtration rate; SCr, serum creatinine