Calcific aortic valve stenosis has become the most common acquired valve disorder with the highest prevalence in the 8th or 9th decade of life [
Acute kidney injury (AKI) is a well-known complication of angiography with the use of iodinated contrast media that accounts for a significantly prolonged hospital stay and worse in-hospital outcome [
TAVI requires the administration of contrast media and preexisting kidney disease is frequent in the currently treated patient population. However, the incidence of AKI, predictors of this complication, and its impact on outcome in patients undergoing TAVI have so far been poorly defined.
Therefore, we sought to assess the incidence of AKI, search for its predictors, and analyze its impact on 30-day as well as midterm outcome in a sizeable group of consecutive patients undergoing TAVI.
A total of 150 consecutive patients with symptomatic aortic stenosis who underwent TAVI in our institution because they were either not suitable for conventional surgical valve replacement or were considered at high operative risk by a multidisciplinary team including cardiologists and cardiac surgeons were included in this study. Ten out of 150 patients had been enrolled in a chronic dialysis program and were therefore excluded from analysis concerning AKI. Before intervention, all patients received left and right heart catheterization. According to the institution policy, written informed consent was obtained for treatment from each patient. Blood samples for hematology and serum chemistry were drawn one day prior to intervention and daily up to 72 hours after treatment. Patients with a previously impaired kidney function (estimated glomerular filtration rate, eGFR <60 mL/min/1,73 m²) received an intravenous prehydration protocol consisting of saline 0.9% with 1200 mg of n-acetyl-cysteine both 12 hours before and after the procedure.
The vascular access site was evaluated by color-coded Doppler sonography and CT-angiography. Valve replacement was performed under general anaesthesia, except in one case which was done under local anaesthesia. All procedures were performed in the catheter laboratory using fluoroscopic guidance and nonionic isoosmolar contrast media iopromide (ultravist 370 (TM), Schering AG, Berlin, Germany) and transoesophageal echocardiography. The patients received either a 23 or 26 mm Edwards-Sapien valve prothesis. Patients not suitable for transfemoral TAVI because of poor vascular access underwent transapical TAVI.
Renal function at baseline and after 48 hours was determined from serum creatinine determined by the method of Jaffé. Since creatinine is known to be an insufficient marker of renal function but estimated glomerular filtration rate (eGFR) is considered most suitable we used the modification of diet in renal disease (MDRD) formula for calculation [
Acute Kidney Injury is divided into three stages by the Acute Kidney Injury Network: stage 1 is defined as a rise in serum creatinine
Logistic EUROScore was calculated by the web-based system (
Differences in basic clinical characteristics between groups were tested by chi-square test for categorical and the ANOVA
Univariate predictors of mortality during followup were analyzed by Cox regression and calculation of hazard rate ratios (HR) with 95% confidence intervals (95% CI). Multivariate analysis of mortality was performed by Cox regression analyses with potential covariates (adjusted HR). As covariates for adjustment, those parameters were chosen which were found to have a
For all tests,
The mean age in the patient group was
Baseline data and periprocedural characteristics with respect to different access modes for valve replacement.
Total | Transfemoral | Transapical |
|
|
---|---|---|---|---|
|
|
|
||
Women, |
91 (61) | 66 (69) | 25 (46) |
|
Age, mean ± s.d., years | 81 ± 7 | 82 ± 6 | 80 ± 7 | 0.2 |
Hypertension, |
115 (77) | 69 (72) | 46 (85) |
|
Endstage renal failure, |
10 (7) | 5 (5) | 5 (9) | 0.06 |
Hypercholesterolemia, |
51 (34) | 31 (32) | 20 (37) | 0.27 |
Diabetes, |
42 (28) | 25 (26) | 17 (31) | 0.56 |
Peripheral occlusive disease, |
37 (25) | 10 (10) | 27 (50) |
|
Coronary heart disease, total, |
79 (53) | 41 (43) | 34 (63) |
|
(1) vessel disease | 25 (17) | 13 (14) | 12 (22) | |
(2) vessel disease | 20 (13) | 14 (15) | 6 (11) | |
(3) vessel disease | 34 (23) | 14 (15) | 20 (37) | |
Previous myocardial infarction, |
36 (24) | 22 (23) | 14 (26) | 0.42 |
Previous CABG, |
34 (23) | 15 (16) | 19 (35) |
|
Previous stroke, |
14 (9) | 7 (7) | 7 (13) |
|
Baseline creatinine, mean ± s.d., |
133.5 ± 109.6 | 116.7 ± 73.4 | 162.7 ± 150.3 |
|
GFR, mean ± s.d., mL/min/1,73 m2 | 53 ± 22 | 55 ± 21 | 49 ± 22 | 0.11 |
Baseline hemoglobin, mean ± s.d., mmol/L | 7.39 ± 1.06 | 7.39 ± 1.06 | 7.39 ± 0.99 | 0.8 |
Hemoglobin 24 hours after intervention, mean ± s.d., mmol/L | 6.27 ± 0.81 | 6.27 ± 0.74 | 6.21 ± 0.93 | 0.53 |
Amount contrast dye, mean ± s.d., mL | 147 ± 58 | 160 ± 57 | 125 ± 53 |
|
STS Score renal failure, % ±s.d. | 7.3 ± 4.2 | 6.8 ± 3.5 | 8.3 ± 5.1 | 0.054 |
STS Score mortality, % ±s.d. | 6.3 ± 3.5 | 5.7 ± 2.7 | 7.1 ± 4.5 |
|
EUROScore, % ±s.d. | 24 ± 14 | 22 ± 13 | 28 ± 16 |
|
All values are expressed as mean ± s.d. or
Ten patients (7%) had already been enrolled in a chronic dialysis program before intervention (5% of TF versus and 9% of TA patients,
The average amount of contrast media used in all patients was
The rate of AKI after pre-TAVI diagnostic right and left heart catheterization in our patient population was 9.2% (
After exclusion of the ten patients who had already been enrolled in a chronic dialysis program before TAVI, 140 patients were left for the analysis concerning the occurrence of acute kidney injury.
The number of patients developing acute kidney injury was 28 (20%).
Need for transient dialysis occurred in six out of these 28 pts. with AKI (21%). Two patients without AKI needed short-term dialysis (one patient was hemofiltrated due to low cardiac output and consecutive renal impairment, another patient acquired septic shock with renal failure).
There was no significant difference regarding weight, height, baseline creatinine, and hemoglobin values in pts. who developed AKI after intervention compared to those who did not (see Table
Parameters associated with acute kidney injury (AKI).
All ( |
With AKI ( |
Without AKI ( |
| |
---|---|---|---|---|
Age (years) ± s.d. | 82 ± 7 | 79 ± 9 | 82 ± 6 |
|
Weight (kg) ± s.d. | 74 ± 16 | 76 ±17 | 74 ± 16 | 0.535 |
Height (cm) ± s.d. | 167 ± 9 | 169 ± 9 | 167 ± 8 | 0.136 |
Baseline creatinine ( |
114.9 ± 53 | 126.4 ± 59.2 | 108.7 ± 45.1 | 0.093 |
GFR (mL/min/1,73 m2) ± s.d. | 55 ± 20 | 51 ± 17 | 57 ± 20 | 0.16 |
Baseline hemoglobin (mmol/L) ± s.d. | 7.45 ± 1.06 | 7.26 ± 1.24 | 7.45 ± 0.99 | 0.35 |
Hemoglobin 24 hours after intervention, mean ± s.d., mmol/L | 6.27 ± 0.81 | 6.21 ± 1.06 | 6.33 ± 0.74 | 0.56 |
Amount of contrast media (mL) ± s.d. | 148 ± 59 | 147 ± 71 | 148 ± 56 | 0.93 |
Diabetes, |
38 (27) | 10 (36) | 28 (25) | 0.19 |
Hypertension, |
108 (77) | 24 (86) | 84 (75) |
|
PAD, |
34 (24) | 7 (25) | 27 (24) | 0.45 |
Previous stroke, |
11 (8) | 2 (7) | 9 (8) | 0.75 |
Previous CABG, |
32 (23) | 9 (32) | 23 (21) |
|
Previous MI, |
34 (24) | 9 (32) | 25 (22) | 0.06 |
CHD, |
74 (53) | 20 (71) | 54 (48) | 0.6 |
Hypercholesterolemia, |
48 (34) | 10 (36) | 38 (34) | 0.73 |
STS Score renal failure, % ±s.d. | 7.3 ± 4.2 | 8.0 ± 5.0 | 7.1 ± 4.0 | 0.32 |
STS Score mortality, % ±s.d. | 6.0 ± 3.4 | 6.0 ± 3.5 | 6.0 ± 3.4 | 0.97 |
EUROScore, % ±s.d. | 24 ± 15 | 27 ± 19 | 23 ± 13 | 0.18 |
All values expressed as mean ± s.d. or
Although baseline creatinine was slightly higher in the AKI group (
The amount of contrast media used during the procedure was also very similar between groups (
Mean hospital stay was significantly longer in pts. with AKI than in those without AKI (
Both, 30-day-mortality (29% versus 7%,
Crude and adjusted cumulative survival are shown in Figure
Cumulative survival in pts. with (dotted lines) and without AKI (solid lines). (a) Crude cumulative survival (days) (HRR 2.7, CI 1.34–5.41,
Predictors of AKI occurrence in univariate and multivariate regression analysis are shown in Tables
Univariate predictors of acute kidney injury.
OR | CI 95% |
|
|
---|---|---|---|
Age | 0.92 | 0.87–0.98 |
|
Diabetes | 1.6 | 0.66–3.83 | 0.3 |
Hypertension | 2.0 | 0.64–6.26 | 0.23 |
PAD | 1.05 | 0.4–2.74 | 0.92 |
CABG | 1.8 | 0.73–4.58 | 0.2 |
MI | 1.65 | 0.66–4.09 | 0.28 |
Moderately reduced LV function* | 1.63 | 0.56–4.7 | 0.37 |
Severely reduced LV function# | 1.54 | 0.44–5.32 | 0.5 |
Baseline creatinine | 1.92 | 0.96–3.83 | 0.06 |
Baseline hemoglobin | 0.89 | 0.69–1.14 | 0.35 |
Amount contrast dye | 1.0 | 0.99–1.01 | 0.93 |
Multivariate predictors of acute kidney injury.
OR | CI 95% |
|
|
---|---|---|---|
Age | 0.93 | 0.87–0.99 |
|
Diabetes | 1.3 | 0.48–3.6 | 0.6 |
Hypertension | 2.0 | 0.54–7.41 | 0.3 |
PAD | 0.76 | 0.25–2.3 | 0.62 |
CABG | 1.49 | 0.5–4.4 | 0.48 |
MI | 1.08 | 0.34–3.42 | 0.89 |
Moderately reduced LV function* | 1.85 | 0.58–5.92 | 0.3 |
Severely reduced LV function# | 1.0 | 0.23–4.3 | 0.9 |
Baseline creatinine | 2.0 | 0.89–4.54 | 0.1 |
Baseline hemoglobin | 0.86 | 0.66–1.14 | 0.3 |
Amount contrast dye | 1.0 | 0.99–1.01 | 0.6 |
Constant | 44.38 | 0.3 |
Neither EuroSCORE (
Morbidity and mortality with respect to access site and development of acute kidney injury (AKI): observed 30-day mortality and predicted renal failure and mortality by STS Score for pts. with and without AKI; AKI = acute kidney injury.
When applying the STS Score renal failure definition to our patient population, 19 pts. (13.6%) developed renal failure. However, the predicted rate of renal failure by STS Score was only 7.3% (
Acute kidney injury after the use of iodinated contrast media in angiography is known to account for a number of adverse effects such as prolonged hospital stay [
In the present study, AKI occurred in 20% of the patients after TAVI with 4% requiring dialysis. This is within the range reported by other investigators. Nuis et al. [
Prehydration in addition to intravenous n-acetyl-cysteine application prior to contrast media exposure is a well-known measure to reduce AKI rates in patients with renal impairment [
Comparing AKI rates and patients after diagnostic and TAVI catheterization no correlation between AKI after diagnostic and valve procedure could be seen implying the lack of a patient-inherent predisposition for AKI occurrence after exposure to contrast media.
This finding complies with the results of Van Linden et al. [
In this context it should be kept in mind that after cardiac surgery without any use of contrast media, the rate of AKI can also reach up to 30% with 1% requiring dialysis treatment [
The markedly adverse effect of the occurrence of AKI on the outcome of TAVI underlines the importance of identifying predictors of this complication as well as appropriate measures for its prevention. In the present study, 30-day mortality and midterm mortality were as high as 29% and 43% in patients with AKI compared to only 7% and 18% in those who did not develop this complication. The difference in survival was even more pronounced when adjusting for differences in baseline characteristics. Similar findings have been reported by other investigators [
It appears obvious that preprocedural chronic kidney disease should be a major risk factor for the development of postprocedural AKI. Sinning et al. [
In addition to preexisting factors, hemodynamic instability with consecutive extreme hypotension caused by rapid pacing, balloon valvuloplasty, and prosthesis deployment during TAVI may account for a significantly higher risk of AKI in patients undergoing TAVI compared to simple angiography or PCI. Arteriosclerotic microembolism may also contribute to temporary deterioration of kidney function. This must be considered when developing measures to reduce the occurrence of AKI after TAVI.
This study has several limitations. Although the data were collected prospectively in consecutive patients undergoing TAVI, the analysis with regard to incidence and predictors of AKI was performed retrospectively. Potentially relevant factors such as red blood cell transfusion, after procedure thrombocytopenia and hemoglobin drop, procedure time, hemodynamic complication or the use of angiotensin converting enzyme inhibitors, and/or angiotensin receptor blockers could not be evaluated. Although the study comprised a sizeable number of TAVI patients, it reflects a single-center experience only and a much larger population is required to perform extensive multivariate analyses in order to better identify risk factors for the development of AKI with relevant impact on the decision making in clinical practice.
Development of AKI is frequent in patients undergoing TAVI. Its occurrence does not appear to be primarily related to the amount of contrast dye used. Furthermore, STS Score does not reliably predict renal failure in this patient population. The occurrence of AKI markedly increases hospital stay as well as 30-day and midterm mortality even after consideration of the baseline risk profile. Thus, improvements in predicting the risk of AKI after TAVI as well as effective measures to reduce the rate of this complication would be essential.
Acute kidney injury
Acute kidney injury network
Coronary artery bypass graft
Coronary heart disease
European System for cardiac operative risk evaluation
Glomerular filtration rate
Myocardial infarction
Peripheral arterial disease
Transapical
Transcatheter aortic valve implantation
Transfemoral
Society of Thoracic Surgeons Score.
H. Baumgartner has conflict of interests with Proctor Edwards Life Science and Executive Committee Source Registry. H. Reinecke has conflict of interests with Proctor and Edwards Life Science.
The authors acknowledge the support of the Deutsche Forschungsgemeinschaft and Open Access Publication Fund of the University of Münster.