Incidence, Risk Factors, and Prediction of Acute Kidney Injury After Off-Pump Coronary Artery Bypass Grafting

Characterization of Risk Prediction Models for Acute Kidney Injury: A Systematic Review and Meta-analysis

Importance

Despite the expansion of published prediction models for acute kidney injury (AKI), there is little evidence of uptake of these models beyond their local derivation nor data on their association with patient outcomes.

Objective

To systematically review published AKI prediction models across all clinical subsettings.

Data Sources

MEDLINE via PubMed (January 1946 to April 2021) and Embase (January 1947 to April 2021) were searched using medical subject headings and text words related to AKI and prediction models.

Study Selection

All studies that developed a prediction model for AKI, defined as a statistical model with at least 2 predictive variables to estimate future occurrence of AKI, were eligible for inclusion. There was no limitation on study populations or methodological designs.

Data Extraction and Synthesis

Two authors independently searched the literature, screened the studies, and extracted and analyzed the data following the Preferred Reporting Items for Systematic Review and Meta-analyses guideline. The data were pooled using a random-effects model, with subgroups defined by 4 clinical settings. Between-study heterogeneity was explored using multiple methods, and funnel plot analysis was used to identify publication bias.

Main Outcomes and Measures

C statistic was used to measure the discrimination of prediction models.

Results

Of the 6955 studies initially identified through literature searching, 150 studies, with 14.4 million participants, met the inclusion criteria. The study characteristics differed widely in design, population, AKI definition, and model performance assessments. The overall pooled C statistic was 0.80 (95% CI, 0.79-0.81), with pooled C statistics in different clinical subsettings ranging from 0.78 (95% CI, 0.75-0.80) to 0.82 (95% CI, 0.78-0.86). Between-study heterogeneity was high overall and in the different clinical settings (eg, contrast medium-associated AKI: I2 = 99.9%; P < .001), and multiple methods did not identify any clear sources. A high proportion of models had a high risk of bias (126 [84.4%]) according to the Prediction Model Risk Of Bias Assessment Tool.

Conclusions and Relevance

In this study, the discrimination of the published AKI prediction models was good, reflected by high C statistics; however, the wide variation in the clinical settings, populations, and predictive variables likely drives the highly heterogenous findings that limit clinical utility. Standardized procedures for development and validation of prediction models are urgently needed.

Risk factors for postoperative acute kidney injury in overweight patients with acute type A aortic dissection

OBJECTIVE

To analyze the clinical characteristics of patients with overweight acute type A aortic dissection, and to explore the risk factors of acute kidney injury in patients with overweight acute type A aortic dissection.

METHODS

From March 2019 to February 2022, the clinical data of 71 patients with acute type a aortic dissection diagnosed by CTA and undergoing surgical treatment with BMI > 24 in the First People's Hospital of Yunnan Province were retrospectively analyzed, and analyzed by univariate and logistic multivariate analysis methods.

RESULTS

The mean BMI of all included patients was 27.23, The mean surface area of all included human populations was 1.833. The mean age of all patients was (52.06 ± 10.71) years old, and 35 patients developed acute kidney injury after surgery. Multi-factor Logistics regression analysis confirmed the risk factors for postoperative acute kidney injury in overweight patients with acute type A aortic dissection, including gender, CPB transit time and intraoperative infusion of suspended red blood cells. Seven patients in the AKI group died in hospital after surgery and two patients died in the non-AKI group.

CONCLUSIONS

Among patients with overweight acute Type A aortic dissection, the incidence of AKI is 49.30%. According to multi-factor Logistics regression analysis, gender, CPB transit time and intraoperative suspended red blood cell volume are independent risk factors for postoperative acute kidney injury in patients with overweight acute Type A aortic dissection.

Use of pre-operative hemoglobin a1c to predict early post-operative renal failure and infection risks in patients who are not diabetics and undergoing elective off pump coronary artery bypass graft surgery

Background

Recent studies have indicated that patients, both with and without diabetes with an increased HbA1c, have a higher rate of adverse outcomes following cardiac surgeries. Our study is focused on to evaluate the prognostic impact of admission value of HbA1c in non-diabetic patients for postoperative renal failure and infections.

Materials and Methods

Plasma HbA1c levels were collected from 200 consecutive nondiabetic patients who got admitted for elective off pump coronary artery bypass graft (CABG) procedure over a 2-year period under two groups, Group A whose HbA1c was < 6% at admission and Group B whose HbA1c was ≥6% and ≤6.4% at admission. After surgery, patients were followed up to see if they have got infection or renal failure as postoperative complication. Student's unpaired t test was used to test the significance of difference between the quantitative variables, Yate's and Fisher's chi square tests were used for qualitative variables.

Results

We found early postoperative renal failure in 14 (3/96 in Group A and 11/104 in Group B) out of 200 patients (7%) and infection in 21 (8/96 in Group A and 13/104 in Group B) out of 200 patients (10.5%). After data analysis, it was noted that there is a positive correlation between HbA1c and postoperative renal failure (P = 0.0213) whereas no association was found between HbA1c and postoperative infections (P = 0.175) in patients undergoing off-pump CABG surgery.

Conclusion

In patients without diabetes, a plasma HbA1c ≥6% was a significant independent predictor for early postoperative renal failure.

Predictive role of arterial lactate in acute kidney injury associated with off-pump coronary artery bypass grafting

Objectives

This observational study aims to explore the predictive role of postoperative arterial lactate in off-pump coronary artery bypass grafting (CABG)-associated acute kidney injury (AKI).

Materials and methods

A total of 500 consecutive patients who underwent off-pump CABG from August 2020 to August 2021 at the Department of Cardiovascular Surgery, Qilu Hospital of Shandong University, were included. Logistic regression analysis was used to confirm the independent risk factors of off-pump CABG-associated AKI. Receiver operating characteristic (ROC) curve was performed to evaluate the discrimination ability and Hosmer–Lemeshow goodness of fit test was performed to evaluate the calibration ability.

Results

The incidence of off-pump CABG-associated AKI was 20.6%. Female gender, preoperative albumin, baseline serum creatinine, 12 h postoperative arterial lactate and duration of mechanical ventilation were independent risk factors. The area under the ROC curve (AUC) of 12 h postoperative arterial lactate for predicting off-pump CABG-associated AKI was 0.756 and the cutoff value was 1.85. The prediction model that incorporated independent risk factors showed reliable predictive ability (AUC = 0.846). Total hospital stay, intensive care unit stay, occurrence of other postoperative complications, and 28-day mortality were all significantly higher in AKI group compared to non-AKI group.

Conclusion

12 h postoperative arterial lactate was a validated predictive biomarker for off-pump CABG-associated AKI. We constructed a predictive model that facilitates the early recognition and management of off-pump CABG-associated AKI.

Effects of Preoperative Statin on Acute Kidney Injury After Off-Pump Coronary Artery Bypass Grafting

Background

Although many patients with coronary artery disease are using statins before off‐pump coronary artery bypass grafting (OPCAB) following current guidelines, recent studies have raised concerns regarding adverse effects of preoperative statins on postoperative kidney function. We evaluated the effects of preoperative statins on acute kidney injury (AKI) after OPCAB.

Methods and Results

We enrolled 1783 consecutive OPCAB patients in either a statin or nonstatin group based on preoperative use of statins. Propensity scores were used to adjust the differences between the groups. The primary outcome was incidence of postoperative AKI according to Kidney Disease: Improving Global Outcomes criteria. To evaluate the dose‐related renal effects of statins, the statin group was divided into low‐ and moderate‐ or higher dose groups based on preoperative statin dose. The incidence of postoperative AKI was 15.7% and 13.5% in the nonstatin and statin groups, respectively, and preoperative statins did not increase the incidence of postoperative AKI (odds ratio: 0.84; 95% CI, 0.61–1.15; P=0.27). In dose‐related analysis, the moderate‐ or higher dose group showed lower incidence of postoperative AKI in comparison with the nonstatin group (odds ratio: 0.61; 95% CI, 0.39–0.95; P=0.03). However, no difference was found between low‐dose and nonstatin groups (odds ratio: 1.17; 95% CI, 0.75–1.84; P=0.49) or between moderate‐ or higher dose and low‐dose statin groups (odds ratio: 0.84; 95% CI, 0.5–1.41; P=0.51) in the incidence of postoperative AKI.

Conclusions

Neither preoperative statin use nor statin dose increased the risk of AKI after OPCAB. Preoperative statin therapy is not harmful in patients receiving OPCAB.

The effect of time between angiography and coronary artery bypass grafting on postoperative acute kidney injury in patients with diabetes mellitus

Background

This study aims to investigate the effect of time interval between coronary angiography and coronary artery bypass grafting surgery on postoperative acute kidney injury in patients with diabetes mellitus.

Methods

Between December 2013 and November 2016, a total of 421 diabetic patients (274 males, 147 females; mean age 60±9.2 years; range, 31 to 84 years) who underwent coronary artery bypass grafting were included in the study. Data including demographic characteristics of the patients, comorbidities, medical, and surgical histories, previous coronary angiographies, and operative and laboratory results were retrospectively analyzed. The patients were divided into two groups as those with acute kidney injury (n=108) and those without acute kidney injury (n=313). The Risk, Injury, Failure, Loss, End-Stage Kidney Disease (RIFLE) criteria were used to define acute kidney injury. The patients were further classified into three subgroups according to the time interval: 0-3 days, 4-7 days, and >7 days.

Results

There was no statistically significant difference in the median time between coronary angiography and coronary artery bypass grafting between the patients with and without acute kidney injury (11.5 and 12.0 days; respectively p=0.871). There was no significant difference in the risk factors for acute kidney injury among the subgroups. Multivariate analysis revealed that previous myocardial infarction (odds ratio [OR]: 5.192, 95% confidence interval [CI]: 2.176-12.38; p<0.001) and the increase in the creatinine levels in the first postoperative day (OR: 4.102 and 95% CI: 1.278- 13.17; p=0.018) were independent predictors of acute kidney injury.

Conclusion

Coronary artery bypass grafting can be performed without any delay after coronary angiography without an increase in the postoperative risk of acute kidney injury in patients with diabetes mellitus.

Development and validation of a pre-scoring system for nonspecific low back pain among general population in Guangzhou: a cross-sectional study

Background

Nonspecific Low Back Pain (NLBP) is a common disease with a low cure rate and significant impact on the population. This study aimed to develop and validate a pre-scoring system for identifying the risk of suffering from NLBP among the general population in Guangzhou.

Methods

A total of 1439 eligible subjects were surveyed in Guangzhou by stratified random sampling and was divided randomly into the development dataset (69.6%) and validation dataset (30.4%) subsequently. Based on the development dataset, potential associated factors (average exercise times weekly, the intensity of daily work, etc.) with NLBP were tested by the sequential logistic regression, and a pre-scoring system was formulated with Sullivan’s method and graded afterward. The internal validity of the system was assessed by AUC and calibration plot, and the external validation was performed in the validation dataset.

Results

The prevalence rates of NLBP in the development dataset and the validation dataset were 12.97 and 13.27%, respectively. Age, BMI, average exercise times weekly, gender, educational level, the intensity of daily work, place of residence, monthly income, overall evaluation of health condition and physiology health were identified as significant factors. The total risk score ranged from 0 to 38, which was split into three risk grades: low risk (0 to 18), intermediate risk (19 to 22) and high risk (23 to 38). The pre-scoring system had an adequate calibration and a good discriminating ability with bootstrap-corrected AUC equaling 0.861 in the development dataset and 0.821 in the validation dataset.

Conclusions

A pre-scoring system that could help clinicians to assess the risk of NLBP in the general population was validated. Further validation of the system in a new population or prospective cohort study is suggested.

Electronic supplementary material

The online version of this article (10.1186/s12889-019-7564-9) contains supplementary material, which is available to authorized users.

[Predictive value of plasma cytokines for acute kidney injury following lung resection surgery: prospective observational study]

BACKGROUND AND OBJECTIVES

Patients undergoing lung resection surgery are at risk of developing postoperative acute kidney injury. Determination of cytokine levels allows the detection of an early inflammatory response. We investigated any temporal relationship among perioperative inflammatory status and development of acute kidney injury after lung resection surgery. Furthermore, we evaluated the impact of acute kidney injury on outcome and analyzed the feasibility of cytokines to predict acute kidney injury.

METHODS

We prospectively analyzed 174 patients scheduled for elective lung resection surgery with intra-operative periods of one-lung ventilation. Fiberoptic broncho-alveolar lavage was performed in each lung before and after one-lung ventilation periods for cytokine analysis. As well, cytokine levels were measured from arterial blood samples at five time points. Acute kidney injury was diagnosed within 48h of surgery based estabilished criteria for its diagnosis. We analyzed the association between acute kidney injury and cardiopulmonary complications, length of intensive care unit and hospital stays, intensive care unit re-admission, and short-term and long-term mortality.

RESULTS

The incidence of acute kidney injury in our study was 6.9% (12/174). Acute kidney injury patients showed higher plasma cytokine levels after surgery, but differences in alveolar cytokines were not detected. Although no patient required renal replacement therapy, acute kidney injury patients had higher incidence of cardiopulmonary complications and increased overall mortality. Plasma interleukin-6 at 6h was the most predictive cytokine of acute kidney injury (cut-off point at 4.89pg.mL^-1).

CONCLUSIONS

Increased postoperative plasma cytokine levels are associated with acute kidney injury after lung resection surgery in our study, which worsens the prognosis. Plasma interleukin-6 may be used as an early indicator for patients at risk of developing acute kidney injury after lung resection surgery.

Predictive value of plasma cytokines for acute kidney injury following lung resection surgery: prospective observational study

Background and objectives

Patients undergoing lung resection surgery are at risk of developing postoperative acute kidney injury. Determination of cytokine levels allows the detection of an early inflammatory response. We investigated any temporal relationship among perioperative inflammatory status and development of acute kidney injury after lung resection surgery. Furthermore, we evaluated the impact of acute kidney injury on outcome and analyzed the feasibility of cytokines to predict acute kidney injury.

Methods

We prospectively analyzed 174 patients scheduled for elective lung resection surgery with intra-operative periods of one-lung ventilation periods. Fiberoptic broncho-alveolar lavage was performed in each lung before and after one-lung ventilation periods for cytokine analysis. As well, cytokine levels were measured from arterial blood samples at five time points. acute kidney injury was diagnosed within 48 h of surgery based on acute kidney injury criteria. We analyzed the association between acute kidney injury and cardiopulmonary complications, length of intensive care unit and hospital stays, intensive care unit re-admission, and short-term and long-term mortality.

Results

The incidence of acute kidney injury in our study was 6.9% (12/174). Acute kidney injury patients showed higher plasma cytokine levels after surgery but differences in alveolar cytokines were not detected. Although no patient required renal replacement therapy, acute kidney injury patients had higher incidence of cardiopulmonary complications and increased overall mortality. Plasma interleukin-6 at 6 h was the most predictive cytokine of acute kidney injury (cut-off point at 4.89 pg.mL⁻¹).

Conclusions

Increased postoperative plasma cytokine levels are associated with acute kidney injury after lung resection surgery in our study, which worsens the prognosis. Plasma interleukin-6 may be used as an early indicator for patients at risk of developing acute kidney injury after lung resection surgery.

Predictors of acute kidney injury in patients undergoing adult cardiac surgery

Background

Acute kidney injury (AKI) after cardiac surgery (CS) is not uncommon and has serious effects on mortality and morbidity. A majority of patients suffer mild forms of AKI. There is a paucity of Indian data regarding this important complication after CS.

Aims and Objectives

The primary objective was to study the incidence of AKI associated with CS in an Indian study population. Secondary objectives were to describe the risk factors associated with AKI-CS in our population and to generate outcome data in patients who suffer this complication.

Methods

Serial patients (n = 400) presenting for adult CS (emergency/elective) at a tertiary referral care hospital in South India from August 2016 to November 2017 were included as the study individuals. The incidence of AKI-CS AKI network (AKIN criteria), risk factors associated with this condition and the outcomes following AKI-CS are described.

Results

Out of 400, 37 (9.25%) patients developed AKI after CS. AKI associated with CS was associated with a mortality of 13.5% (no AKI group mortality 2.8%, P = 0.001 [P < 0.05]). When AKI was severe enough to need renal replacement therapy, the mortality increased to 75%. Patients with AKI had a mean hospital stay 16.92 ± 12.75 days which was comparatively longer than patients without AKI (14 ± 7.98 days). Recent acute coronary syndrome, postoperative atrial fibrillation, and systemic hypertension significantly predicted the onset of AKI-CS in our population.

Conclusions

The overall incidence of AKI-CS was 9.25%. The incidence of AKI-CS requiring dialysis (Stage 3 AKIN) AKI-CS was lower (2%). However, mortality risks were disproportionately high in patients with AKIN Stage 3 AKI-CS (75%). There is a need for quality improvement in the care of patients with AKI-CS in its most severe forms since mortality risks posed by the development of Stage 3 AKIN AKI is higher than reported in other index populations from high resource settings.

Impact of occult renal disease on the outcomes of off-pump and on-pump coronary artery bypass grafting

Purpose

Occult renal disease (ORD) is a clinical condition in which glomerular filtration rate (GFR) is less than 60 ml/min/1.73 m², while serum creatinine is ≤ 1.3 mg/dl. The aim of the study was to compare the incidence of postoperative stage I acute kidney injury (AKI) according to Acute Kidney Injury Network (AKIN) classification in patients with ORD undergoing either off-pump or on-pump coronary artery bypass grafting.

Methods

A single center prospective randomized study was conducted from March 2011 through January 2014. A total of 120 coronary artery disease (CAD) patients with ORD undergoing coronary artery bypass grafting (CABG) were randomized to either off-pump (group1, n = 62) or on-pump (group2, n = 58) CABG in 1:1 ratio by computer-generated random number table. The GFR and serum creatinine levels were measured preoperatively and postoperatively on day 1 and day 5. The primary outcome (postoperative AKI (stage I)) and secondary outcomes (AKI (stage III) requiring renal replacement therapy (RRT) death, myocardial infarction (MI), cerebrovascular accident, atrial fibrillation (AF), and re-exploration for bleeding) at 30 days were analyzed between the groups.

Results

There is no significant difference in baseline characteristics of patients between off-pump and on-pump group. The incidence of postoperative AKI (stage I) was similar between on-pump (20.69%) and off-pump (16.13%) groups (p = 0.51). There was no significant difference in mortality (p = 0.33), postoperative MI (p = 0.34), cerebrovascular accident (p = 1.00), re-exploration (p = 0.96), and AF (p = 0.50). The number of patients of stage III AKI requiring RRT was higher in the off-pump group (3 patients, 4.8%) and none in the on-pump group (p = 0.08).

Conclusions

This study demonstrated that on-pump CABG is associated with significantly lower GFR and significantly higher serum creatinine on postoperative day 1 which return to baseline by postoperative day 5. In patients with ORD undergoing CABG, the incidence of postoperative AKI and major adverse cardiac and cerebrovascular events were similar between off-pump or on-pump CABG patients.

The Accuracy of Urinary TIMP-2 and IGFBP7 for the Diagnosis of Cardiac Surgery-Associated Acute Kidney Injury: A Systematic Review and Meta-Analysis

Background:

Tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) are recent promising markers for identification of cardiac surgery-associated acute kidney injury (CSA-AKI). The aim of this study was systematically and quantitatively to evaluate the accuracy of urinary TIMP-2 and IGFBP7 for the diagnosis of CSA-AKI.

Methods:

Three databases including PubMed, ISI web of knowledge, and Embase were systematically searched from inception to March 2018. Two investigators conducted the processes of literature search study selection, data extraction, and quality evaluation independently. Meta-DiSc and STATA were used for all statistical analyses.

Results:

A total of 8 studies comprising 552 patients were included in this meta-analysis. Pooled sensitivity and specificity with corresponding 95% confidence intervals (CIs) were 0.79 (95% CI, 0.71-0.86, I 2 = 74.2%) and 0.76 (95% CI, 0.72-0.80, I 2 = 80.8%), respectively. Pooled positive likelihood ratio (LR), negative LR, and diagnostic odds ratio were 3.49 (95% CI, 2.44-5.00, I 2 = 61.5%), 0.31(95% CI, 0.19-0.51, I 2 = 51.8%), and 14.89 (95% CI, 7.31-30.32, I 2 = 27.9%), respectively. The area under curve estimated by summary receiver operating characteristic was 0.868 (standard error [SE] 0.032) with a Q* value of 0.799 (SE 0.032). Sensitivity analysis demonstrated that one study notably affected the stability of pooled results. One of the subgroups investigated—AKI threshold—could account for partial heterogeneity.

Conclusion:

Urinary TIMP-2 and IGFBP7 is a helpful biomarker for early diagnosis of CSA-AKI. And, the potential of this biomarker with a broader spectrum of clinical settings may be the focus of future studies.

Early Detection of Postoperative Acute Kidney Injury in Acute Stanford Type A Aortic Dissection With Doppler Renal Resistive Index

OBJECTIVES

This study aimed to evaluate the early efficiency of Doppler renal resistive index (DRRI) in prediction of acute kidney injury (AKI) after surgery in acute Stanford Type A aortic dissection (AAAD) patients.

METHODS

Sixty-one AAAD patients who planned to receive Sun's surgical management were prospectively enrolled. The DRRI was measured by ultrasonography Doppler on the day before surgery (DRRI_pre ), on admission to the intensive care unit (DRRI_T0 ), 6 hours after surgery (DRRI_T6 ), 24 hours after surgery (DRRI_T24 ), and 48 hours after surgery (DRRI_T48 ). The maximum DRRI value (DRRI_max ) was recorded. The AKI was evaluated according to the classifications of the Acute Kidney Injury Network. The DRRI and serum creatinine (sCr) were compared between the pre- and postoperative time stations, as well as between the AKI and no-AKI groups.

RESULTS

Thirty-nine (63.9%) patients suffered from AKI, and 12 (19.6%) patients received dialysis. No significant difference was found in DRRI_pre (0.63 ± 0.04 versus 0.65 ± 0.06, P = .059) and sCr_pre (84.13 ± 23.77 versus 94.29 ± 51.11, P = .383) between the two groups with and without AKI. Both the DRRI and sCr increased significantly after surgery in the AKI groups (P < .001). However, the DRRI reached its maximum 6 hours after surgery, whereas the sCr reached its maximum after 24 hours. Both the DRRI and sCr improved 48 hours after surgery. The area under the receiver operating characteristic curve for DRRI_max (0.864, 95% confidence interval: 0.770-0.957) and DRRI_T6 (0.861, 95% confidence interval: 0.766-0.957) was larger than the other three DRRIs measured at different time points. The cutoff value of DRRI_max was 0.71, a sensitivity of 76.9% and specificity of 95.5%.

CONCLUSIONS

Postoperative DRRI predicts the AKI earlier than sCr after AAAD surgery. The best time to detect DRRI was 6 hours after surgery.

Risk factors for continuous renal replacement therapy after surgical repair of type A aortic dissection

BACKGROUND

To identify the risk factors for continuous renal replacement therapy (CRRT) following surgical repair of type A aortic dissection (TAAD) using the total arch replacement and frozen elephant trunk (TAR + FET) technique.

METHODS

The study included 330 patients with TAAD repaired using TAR + FET between January 2014 and April 2015. Mean age was 47.1±10.2 years (range, 18-73 years) and 242 were male (73.3%). Univariate and multivariate analyses were used to identify the risk factors for CRRT.

RESULTS

Postoperative CRRT was required in 38 patients (mean age 50.7±10.0 years; 27 males). Operative death occurred in 12 patients (3.6%, 12/330). The mortality rate was 23.7% (9/38) in patients with CRRT and 1.0% (3/292) in those without CRRT (P<0.001). Factors associated with CRRT were age (50.7±10.0 vs. 46.7±10.2 years, P=0.023), preoperative serum creatinine (sCr) (135.0±154.2 vs. 85.7±37.0 µmol/L, P<0.001), emergency operation (89.5% vs. 73.3%, P=0.030), cardiopulmonary bypass (CPB) time (265.2±98.8 vs. 199.7±44.2 minutes, P<0.001), cross-clamp time (144.6±54.8 vs. 116.3±33.2 minutes, P<0.001), the amount of red blood cell (8.0±5.2 vs. 3.7±3.3 unit, P<0.001) and fresh frozen plasma (507.8±350.3 vs. 784.2±488.5 mL, P<0.001) transfused intraoperatively, preoperative D-dimmer level (11,361.0 vs. 2,856.7 mg/L, P<0.001) and reexploration for bleeding (15.8% vs. 2.4%, P<0.001). In multivariate analysis, risk factors for CRRT were CPB time (minute) [odds ratio (OR) 1.018; 95% confidence interval (CI), 1.007-1.029; P=0.002], preoperative sCr level (µmol/L) (OR, 1.008; 95% CI, 1.000-1.015; P=0.040), and the amount of red blood cell transfused intraoperatively (unit) (OR, 1.206; 95% CI, 1.077-1.350; P<0.001).

CONCLUSIONS

In this series of patients with TAAD, the time of CPB (minute), sCr level (µmol/L) and the amount of red blood cell transfused intraoperatively (unit) were risk factors for CRRT after TAR + FET.

Results of Protocol-based Perioperative Management in Off-Pump Coronary Artery Bypass Grafting for Patients with Non-dialysis-dependent Chronic Kidney Disease

BACKGROUND

Recent studies have demonstrated the benefits of off-pump coronary bypass grafting over the on-pump technique in patients with chronic kidney disease (CKD). To further reduce the risk of acute kidney injury and the need for renal replacement therapy, even in patients undergoing off-pump coronary artery bypass grafting, we adopted protocol-based perioperative management for patients with CKD.

METHODS

From December 2012 to March 2015, 265 patients underwent isolated off-pump coronary artery bypass grafting. To analyze renal function in a stable condition, we excluded 12 dialysis-dependent end stage renal failure and 10 emergency or urgent cases. Among the remaining 243 patients, 208 patients had normal kidney function (normal group), and 35 patients had CKD (CKD group). Minimizing contrast exposure, ensuring adequate hydration, using strict drug dosage adjustment, and optimizing hemodynamic status were key elements of the protocol for the CKD group.

RESULTS

The risk of acute kidney injury was about ×3 higher in the CKD group than in the normal group (p=0.01). Estimated glomerular filtration rates and serum creatinine levels deteriorated until the third postoperative day in the CKD group. However, by adopting protocol-based perioperative management, this transient renal dysfunction recovered to preoperative levels by the fifth postoperative day without requiring renal replacement therapy in all cases.

CONCLUSION

Off-pump coronary bypass surgery combined with this protocol-based perioperative management strategy in patients with non-dialysis-dependent CKD could mostly be performed without renal replacement therapy.

Factors associated with postoperative requirement of renal replacement therapy following off-pump coronary bypass surgery

Cardiopulmonary bypass usage provokes a systemic inflammatory response resulting in deterioration of renal function. However, risk factors for requiring renal replacement therapy (RRT) following off-pump coronary artery bypass graft surgery (CABG) have not yet been fully elucidated. We reviewed 718 consecutive patients undergoing elective off-pump CABG at our institution, excluding patients on chronic hemodialysis preoperatively. Sub-analysis of patients with preserved renal function, defined as a creatinine level below a cut-off value of 1.12 mg/dL (obtained by receiver operating characteristic curve), was also performed. Of the 718 patients, 41 (5.7 %) required RRT. There were 556 patients (77.4 %) with preserved renal function preoperatively, and 13 (2.4 %) of these required postoperative RRT. Multivariate analysis revealed that age (years) and preoperative serum creatinine (mg/dL) and brain natriuretic peptide (BNP) levels (pg/dL) were associated with RRT [odds ratios (OR) 1.052, 95 % confidence interval (CI) 9.064 and 1.001, respectively, all p < 0.05] in the total population, whereas low albumin concentration was the only independent predictor for RRT in patients with preserved renal function (OR 0.062, p < 0.0001). When creatinine levels were below 1.5 mg/dL, the predictive power of hypoalbuminemia for RRT requirement overwhelmed that of creatinine or BNP levels. Older age, preoperative elevated creatinine and BNP levels were associated with a requirement for RRT following off-pump CABG. In patients with preserved renal function, hypoalbuminemia was most significantly related to the RRT requirement.

Preoperative Prophylactic Intraaortic Balloon Pump Reduces the Incidence of Postoperative Acute Kidney Injury and Short-Term Death of High-Risk Patients Undergoing Coronary Artery Bypass Grafting: A Meta-Analysis of 17 Studies

This meta-analysis investigated the effects of preoperative prophylactic intraaortic balloon pump placement on postoperative renal function and short-term death of high-risk patients undergoing coronary artery bypass grafting. We found that preoperative prophylactic intraaortic balloon pump support reduced the incidence of coronary artery bypass grafting-associated acute kidney injury and short-term death and dramatically decreased the incidence of postoperative renal replacement therapy by 82% compared with high-risk patients without the procedure. This is the first meta-analysis to demonstrate significant beneficial effects of preoperative prophylactic intraaortic balloon pump on renal function in high-risk patients undergoing coronary artery bypass grafting.

Utilizing electronic health records to predict acute kidney injury risk and outcomes: workgroup statements from the 15(th) ADQI Consensus Conference

The data contained within the electronic health record (EHR) is "big" from the standpoint of volume, velocity, and variety. These circumstances and the pervasive trend towards EHR adoption have sparked interest in applying big data predictive analytic techniques to EHR data. Acute kidney injury (AKI) is a condition well suited to prediction and risk forecasting; not only does the consensus definition for AKI allow temporal anchoring of events, but no treatments exist once AKI develops, underscoring the importance of early identification and prevention. The Acute Dialysis Quality Initiative (ADQI) convened a group of key opinion leaders and stakeholders to consider how best to approach AKI research and care in the "Big Data" era. This manuscript addresses the core elements of AKI risk prediction and outlines potential pathways and processes. We describe AKI prediction targets, feature selection, model development, and data display.

Risk factors for acute kidney injury in overweight patients with acute type A aortic dissection: a retrospective study

BACKGROUND

To identify risk factors for acute kidney injury (AKI) in overweight patients who underwent surgery for acute type A aortic dissection (TAAD).

METHODS

A retrospective study including 108 consecutive overweight patients [body mass index (BMI) ≥24] between December 2009 and April 2013 in Beijing Anzhen Hospital has been performed. AKI was defined by Acute Kidney Injury Network (AKIN) criteria, which is based on serum creatinine (sCr) or urine output.

RESULTS

The mean age of the patients was 43.69±9.66 years. Seventy-two patients (66.7%) developed AKI during the postoperative period. A logistic regression analysis was performed to identify two independent risk factors for AKI: elevated preoperative sCr level and 72-h drainage volume. Renal replacement therapy (RRT) was required in 15 patients (13.9%). The overall postoperative mortality rate was 7.4%, 8.3% in AKI group and 5.6% in non-AKI group. There is no statistically significant difference between the two groups (P=0.32).

CONCLUSIONS

A higher incidence of AKI (66.7%) in overweight patients with acute TAAD was confirmed. The logistic regression model identified elevated preoperative sCr level and 72-h drainage volume as independent risk factors for AKI in overweight patients. We should pay more attention to prevent AKI in overweight patients with TAAD.

Preoperative factors associated with postoperative requirements of renal replacement therapy following cardiac surgery

Renal dysfunction is a major adverse event after cardiovascular surgery. Therefore, the preoperative prediction of which patients will require renal replacement therapy (RRT) after cardiac surgery is an important issue. In the present study, 1,822 consecutive patients who underwent cardiovascular surgery from 2008 and 2013 at a single institution were reviewed. Patients who were already receiving long-term hemodialysis before surgery (n = 134) were excluded. The remaining 1,688 patients were separated into 2 groups: those requiring postoperative RRT and those without RRT requirement. A total of 128 patients (7.6%) required RRT. Patients requiring RRT had greater perioperative blood loss, longer intubation time, and longer hospital stays (p <0.0001 for all). Multivariate analysis revealed that cardiopulmonary bypass use, preoperative body surface area, the left ventricular ejection fraction, serum albumin, and creatinine were independent risk factors for postoperative RRT (odds ratios 2.435, 0.204, 0.976, 0.556, and 5.394, 95% confidence intervals 1.471 to 4.140, 0.054 to 0.841, 0.962 to 1.025, 0.363 to 0.860, and 3.671 to 8.223, respectively, p <0.05 for all). A subgroup of patients with relatively preserved renal function before surgery (creatinine <1.12 mg/dl, a cut-off value for RRT requirement obtained from receiver-operating characteristic curve analysis [area under the curve 0.74748, sensitivity 60.2%, specificity 85.0%]) showed that preoperative serum albumin concentration was most significantly associated with postoperative RRT requirement (odds ratio 0.048, 95% confidence interval 0.023 to 0.095, p <0.0001). In conclusion, cardiopulmonary bypass use, preoperative renal impairment as reflected by elevated creatinine level, small body size, a low left ventricular ejection fraction, and hypoalbuminemia were associated with a requirement for postoperative RRT. In patients with preserved renal function, hypoalbuminemia was most significantly related to requirement for RRT.

Perioperative risk factors for acute kidney injury after liver resection surgery: an historical cohort study

PURPOSE

This study aimed to identify the incidence and risk factors for acute kidney injury (AKI) after liver resection surgery and to clarify the relationship between postoperative AKI and outcome.

METHODS

We conducted a historical cohort study of patients who underwent liver resection surgery with sevoflurane anesthesia from January 2004 to October 2011. Acute kidney injury was diagnosed based on the Acute Kidney Injury Network classification within 72 hr after the surgery. Patient data, surgical and anesthetic data, and laboratory data were extracted manually from the patients' electronic charts. Multivariable logistic regression analysis was used to identify perioperative risk factors for postoperative AKI.

RESULTS

Acute kidney injury was diagnosed in 78 of 642 patients (12.1%; 95% confidence interval [CI]: 9.7 to 14.9). Multivariable analysis showed an independent association between postoperative AKI and preoperative estimated glomerular filtration rate (adjusted odds ratio [aOR] 0.74; 95% CI: 0.64 to 0.85), preoperative hypertension (aOR 2.10; 95% CI: 1.11 to 3.97), and intraoperative red blood cell transfusion (aOR 1.04; 95% CI: 1.01 to 1.07). Development of AKI within 72 hr after liver resection surgery was associated with increased hospital mortality, prolonged length of stay, and increased rates of mechanical ventilation, reintubation, and renal replacement therapy.

CONCLUSION

Perioperative risk factors for AKI after liver resection surgery are similar to those established for other surgical procedures. Further studies are needed to establish causality and to determine whether interventions on modifiable risk factors can reduce the incidence of postoperative AKI and improve patient outcome. This study was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN 000008089).

Incidence and risk factors of acute kidney injury after thoracic aortic surgery for acute dissection

BACKGROUND

Previous studies have reported a high incidence of acute kidney injury (AKI) after thoracic aortic surgery in heterogeneous patient cohorts, including various aortic diseases and the use of deep hypothermic circulatory arrest. Moderate hypothermia with cerebral perfusion makes deep hypothermia nonessential, but can make end organs susceptible to ischemia during circulatory arrest. We investigated the incidence and risk factors of AKI after thoracic aortic surgery with and without moderate hypothermic circulatory arrest for acute dissection.

METHODS

We reviewed the medical records of 98 patients undergoing graft replacement of the thoracic aorta for acute dissection between 2008 and 2011 at a university hospital. Acute kidney injury was defined by RIFLE criteria, which is based on serum creatinine or glomerular filtration rate.

RESULTS

The mean age was 55±15 years. The surgical procedures, 96% of which were emergencies, involved the ascending aorta (67%), aortic arch (41%), descending aorta (41%), and aortic valve (5%). Moderate hypothermic circulatory arrest was performed in 75%. The overall incidence of AKI was 54%, and 11% of 98 patients required renal replacement therapy. Thirty-day mortality increased with AKI severity (p=0.002). Independent risk factors for AKI were long cardiopulmonary bypass duration (>180 minutes; odds ratio, 7.50; p=0.008) and preoperative serum creatinine level (odds ratio, 8.43; p=0.016).

CONCLUSIONS

Acute kidney injury was common after thoracic aortic surgery for acute dissection with or without moderate hypothermic circulatory arrest and worsened 30-day mortality. Prolonged cardiopulmonary bypass and increased preoperative serum creatinine were independent risk factors for AKI, but moderate hypothermic circulatory arrest was not.

Preoperative hypoalbuminemia is a major risk factor for acute kidney injury following off-pump coronary artery bypass surgery

PURPOSE

To investigate the association between preoperative low serum albumin level and acute kidney injury (AKI) after off-pump coronary artery bypass surgery (OPCAB) METHOD: We assessed preoperative and perioperative risk factors, and preoperative serum albumin concentration in 1,182 consecutive adult patients with preoperative normal renal function who underwent OPCAB surgery. Each patient was categorized by maximal Acute Kidney Injury Network (AKIN) criteria based on creatinine changes within the first 48 h after OPCAB. Logistic regression and propensity analyses were performed to evaluate the association between preoperative low serum albumin level and postoperative AKI.

RESULTS

Of the 1,182 patients, 334 (28.3%) developed AKI. Risk factors for AKI were old age, diabetes mellitus, maximal cardiovascular component of the sequential organ failure assessment score, perioperative transfusion, and postoperative C-reactive protein concentration. The risk of AKI was negatively correlated with the volume of crystalloid infused during surgery. A preoperative serum albumin level of <4.0 g/dl was independently associated Ith postoperative AKI [multivariable logistic analysis: odds ratio (OR) 1.83, 95 % confidence interval (CI) 1.27-2.64; P = 0.001; propensity analysis: OR 1.62, 95 % CI 1.12-2.35; P = 0.011). AKI was associated with prolonged stay in the intensive care unit and hospital and a high mortality rate.

CONCLUSIONS

Preoperative low serum albumin level is an independent risk factor for AKI, and postoperative AKI is associated with poor outcomes after OPCAB in patients with preoperative normal renal function.