AKI associated with cardiac surgery

Perioperative THR-184 and AKI after Cardiac Surgery

AKI after cardiac surgery is associated with mortality, prolonged hospital length of stay, use of dialysis, and subsequent CKD. We evaluated the effects of THR-184, a bone morphogenetic protein-7 agonist, in patients at high risk for AKI after cardiac surgery. We conducted a randomized, double-blind, placebo-controlled, multidose comparison of the safety and efficacy of perioperative THR-184 using a two-stage seamless adaptive design in 452 patients between 18 and 85 years of age who were scheduled for nonemergent cardiac surgery requiring cardiopulmonary bypass and had recognized risk factors for AKI. The primary efficacy end point was the proportion of patients who developed AKI according to Kidney Disease Improving Global Outcomes (KDIGO) criteria. The proportion of patients who developed AKI within 7 days of surgery was similar in THR-184 treatment groups and placebo groups (range, 74%-79%; P=0.43). Prespecified secondary end point analysis did not show significant differences in the severity of AKI stage (P=0.53) or the total duration of AKI (P=0.44). A composite of death, dialysis, or sustained impaired renal function by day 30 after surgery did not differ between groups (range, 11%-20%; P=0.46). Safety-related outcomes were similar across all treatment groups. In conclusion, compared with placebo, administration of perioperative THR-184 through a range of dose exposures failed to reduce the incidence, severity, or duration of AKI after cardiac surgery in high-risk patients.

Perioperative body weight change is associated with in-hospital mortality in cardiac surgical patients with postoperative acute kidney injury

Background

Postoperative acute kidney injury (AKI) is common following cardiac surgery (CS). Body weight (BW) may be an amenable variable by representing the summation of the nutritional and the fluid status. However, the predictive role of perioperative BW changes in CS patients with severe postoperative AKI is never explored. This study aimed to evaluate this association.

Methods

This study was conducted using a prospectively collected multicenter cohort, NSARF (National Taiwan University Hospital Study Group on Acute Renal Failure) database. The adult CS patients with postoperative AKI requiring renal replacement therapy (RRT), who had clear initial consciousness, received CS within 14 days of hospitalization, and underwent RRT within seven days after CS in intensive care units from January 2001 to January 2014 were enrolled. With the endpoint of 30-day postoperative mortality, we evaluated the association between the clinical factors denoting fluid status and patients outcomes.

Results

A total of 188 patients (70 female, mean age 63.7 ± 15.2 years) were enrolled. Comparing with the survivors (n = 124), the non-survivors (n = 64) had a significantly higher perioperative BW change [3.6 ± 6.1% versus 0.1 ± 8.3%, p = 0.003] but not the postoperative and pre-RRT BW changes. By using multivariate Cox proportional hazards model, the independent indicators of 30-day postoperative mortality included perioperative BW change (p = 0.026) and packed red blood cells transfusion (p = 0.007), postoperative intra-aortic balloon pump (p = 0.001) and central venous pressure level (p = 0.005), as well as heart rate (p = 0.022), sequential organ failure assessment score (p < 0.001), logistic organ dysfunction score (p = 0.001), and blood total bilirubin level (p = 0.044) at RRT initiation. The generalized additive models further demonstrated, in a multivariate manner, that the mortality risk rose significantly during a perioperative BW change of 2% to 15%.

Conclusions

Perioperative BW change was independently associated with an increased risk for 30-day postoperative mortality in CS patients with RRT-requiring AKI.

Remote ischaemic preconditioning reduces acute kidney injury in adult patients undergoing cardiac surgery with cardiopulmonary bypass: a meta-analysis

This article represents the first attempt to perform a pooled analysis about remote ischaemic preconditioning (RIPC) in reduction of acute kidney injury (AKI) of adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). A systematic search was performed using PubMed (1966-5 January 2016), the Cochrane Library (1996-5 January 2016), the Web of Science (1986-5 January 2016) and Chinese database (SinoMed) (1978-5 January 2016) to identify studies that have described the effect of RIPC on AKI in adult patients undergoing cardiac surgery with CPB. The outcomes used for this analysis included the incidence of AKI and the need for renal replacement therapy (RRT). Thirteen randomized controlled trials (4370 participants) were included in this analysis. RIPC significantly reduced the risk of AKI (risk ratio, 0.81; 95% confidence interval, [0.66, 0.99]; P = 0.04; I2 = 46%) for adult patients compared with control group. However, there was no significant difference with respect to the incidence of RRT between the two groups. The present meta-analysis found that RIPC may reduce the incidence of AKI among adult patients following cardiac surgery with CPB. Adequately powered trials are warranted to provide further corroboration of our findings in the future.

A new plasma biomarker enhance the clinical prediction of postoperative acute kidney injury in patients with hepatocellular carcinoma

BACKGROUND

The ratio of serum γ-glutamyl transferase (GGT) to alanine aminotransferase (ALT) (GGT/ALT) is a marker for evaluating effects to antivirotic treatment and a helpful predictive factor for the prognosis of Child-Pugh A hepatocellular carcinoma (HCC) patients after surgery. The relationship between the incidence of postoperative acute kidney injury (AKI) and preoperative GGT/ALT is studied in hepatectomized hepatitis B- or C- associated HCC patients.

METHODS

A total of 253 hepatitis B or C virus-related HCC patients undergoing hepatectomy between September 2012 and August 2016 at our hospital were included in the retrospective study. Serum ALT and GGT value were recorded, and the GGT/ALT was computed. AKI was defined that based on the "Kidney Disease Improving Global Outcomes (KDIGO) criteria".

RESULTS

AKI was observed in 22 (8.7%) patients. Mean GGT/ALT of patients with AKI was significantly higher than in those without it (6.0 vs 2.1, P<0.001). Multivariate analysis revealed an increase in GGT/ALT as an independent risk factor for AKI in hepatitis B- or C- associated HCC patients, particularly in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A staged HCC (odds ratio (OR) 1.400, P<0.001). Multivariate analysis showed that ALT (OR 0.966, P=0.044) was somewhat inversely associated with the incidence of AKI in hepatitis B- or C- associated HCC patients. The best cutoff point of GGT/ALT was 2.92. Multivariate analysis showed that preoperative GGT/ALT ≥2.92 predicted poor prognosis of postoperative AKI in patients with HCC after hepatectomy (odds ratio 17.697, P<0.001). After propensity score matching, preoperative GGT/ALT ≥2.92 remained an independent risk factor for AKI in HCC patients (OR 13.947, P=0.003).

CONCLUSIONS

The GGT/ALT of patients with AKI was significantly higher than those without it. Evaluation of GGT/ALT before surgery can be a helpful predictive tool for postoperative AKI in hepatitis B- or C- associated HCC patients undergoing hepatectomy, particularly in patients with BCLC stage 0 or A staged HCC. Hepatitis B- or C- associated HCC patients with low ALT especially within the normal range may have a high risk of AKI. However, the reason remains to be elucidated.

Haptoglobin 2-2 Phenotype Is Associated With Increased Acute Kidney Injury After Elective Cardiac Surgery in Patients With Diabetes Mellitus

BACKGROUND

Recent studies reported an association between the 2-2 phenotype of haptoglobin (Hp 2-2) and increased cardiorenal morbidity in nonsurgical diabetic patients. Our goal was to determine whether the Hp 2-2 phenotype was associated with acute kidney injury (AKI) after elective cardiac surgery in patients with diabetes mellitus.

METHODS AND RESULTS

We prospectively enrolled 99 diabetic patients requiring elective cardiac surgery with cardiopulmonary bypass. Haptoglobin phenotypes were determined by gel electrophoresis. Cell-free hemoglobin, haptoglobin, and total serum bilirubin were quantified as hemolysis markers. The primary outcome was postoperative AKI, as defined by the Acute Kidney Injury Network classification. The incidence of AKI was significantly higher in Hp 2-2 patients compared with patients without this phenotype (non-Hp-2-2; 55.6% versus 27%, P<0.01). The need for renal replacement therapy was also significantly higher in the Hp 2-2 group (5 patients versus 1 patient, P=0.02). Thirty-day mortality (3 versus 0 patients, P=0.04) and 1-year mortality (5 versus 0 patients, P<0.01) were also significantly higher in patients with the Hp 2-2 phenotype. In multivariable analysis, Hp 2-2 was an independent predictor of postoperative AKI (P=0.01; odds ratio: 4.17; 95% confidence interval, 1.35-12.48).

CONCLUSIONS

Hp 2-2 phenotype is an independent predictor of postoperative AKI and is associated with decreased short and long-term survival after cardiac surgery in patients with diabetes mellitus.

Perioperative Low Arterial Oxygenation Is Associated With Increased Stroke Risk in Cardiac Surgery

BACKGROUND

Both patient characteristics and intraoperative factors have been associated with a higher risk of stroke after cardiac surgery. We hypothesized that poor systemic oxygenation in the perioperative period is associated with increased risk of stroke following cardiopulmonary bypass.

METHODS

In this study of 251 adult patients who underwent cardiopulmonary bypass procedures at a single center from 2003 to 2006, cases (patients with a postoperative stroke at least 24 hours after surgery) were matched 1:2 to controls without stroke. Minimum and average partial pressure of oxygen in arterial blood (PaO2) values, from arterial blood gas values during and up to 24 hours after surgery, were evaluated as continuous and categorical predictors. Conditional logistic regression models adjusted for potential confounders (demographics, comorbidities, and intraoperative variables) were used to evaluate associations between PaO2 variables and stroke status.

RESULTS

Lower nadir PaO2 values were associated with postoperative stroke, with estimated odds of stroke increasing over 20% (adjusted odds ratio [OR], 1.23; 95% confidence interval [CI], 1.07-1.41) per 10 mm Hg lower nadir PaO2, and similarly increased odds of stroke per lower quartile of nadir PaO2 (OR, 1.60; 95% CI, 1.19-2.16). When average PaO2 was considered, odds of stroke was also increased (adjusted OR, 1.39 per lower quartile of mean PaO2; 95% CI, 1.05-1.83). Having a nadir PaO2 value in the lowest versus any other quartile was associated with an estimated 2.41-fold increased odds of stroke (95% CI, 1.22-4.78). Quartile of nadir but not average PaO2 results remained significant after adjustment for multiple comparisons.

CONCLUSIONS

Odds of stroke after cardiac surgery are increased in patients with a low minimum PaO2 within 24 hours of surgery. Results should be validated in an independent cohort. Further characterizing the underlying etiology of hypoxic episodes will be important to improve patient outcomes.

Neutrophil gelatinase-associated lipocalin prior to cardiac surgery predicts acute kidney injury and mortality

OBJECTIVE

We aimed to investigate whether preoperative serum neutrophil gelatinase-associated lipocalin (sNGALpre-op) predicted postoperative acute kidney injury (AKI) during hospitalisation and 1-year cardiovascular and all-cause mortality following adult cardiac surgery.

METHODS

This study was a post hoc analysis of the Effect of Remote Ischemic Preconditioning on Clinical Outcomes in Patient Undergoing Coronary Artery Bypass Graft Surgery trial involving adult patients undergoing coronary artery bypass graft. Postoperative AKI within 72 hours was defined using the International Kidney Disease: Improving Global Outcomes classification.

RESULTS

1371 out of 1612 patients had data on sNGALpre-op. The overall 1-year cardiovascular and all-cause mortality was 5.2% (71/1371) and 7.7% (105/1371), respectively. There was an observed increase in the incidence of AKI from the first to the third tertile of sNGALpre-op (30.5%, 41.5% and 45.9%, respectively, p<0.001). There was also an increase in both cardiovascular and all-cause mortality from the first to the third tertile of sNGALpre-op, linear trend test with adjusted p=0.018 and p=0.013, respectively. The adjusted HRs for those in the second and third tertiles of sNGALpre-op compared with the first tertile were 1.60 (95% CI 0.78 to 3.25) and 2.22 (95% CI 1.13 to 4.35) for cardiovascular mortality, and 1.25 (95% CI 0.71 to 2.22) and 1.91 (95% CI 1.13 to 3.25) for all-cause mortality at 1 year.

CONCLUSION

In a cohort of high-risk adult patients undergoing cardiac surgery, there was an increase in postoperative AKI and 1-year mortality from the first to the third tertile of preoperative serum NGAL. Those in the last tertile (>220 ng/L) had an estimated twofold increase risk of cardiovascular and all-cause mortality at 1 year.

CLINICAL TRIAL REGISTRATION

NCT101247545; Post-results.

Appropriate blood component therapy can reduce postcardiac surgery acute kidney injury through packed cell transfusion reduction

Background:

Acute kidney injury (AKI) can happen due to different factors such as anemia. Packed cell (PC) transfusion is an important cause of AKI occurrence. The aim of the study is to investigate whether appropriate blood component (BC) therapy can reduce blood transfusion and it would result in AKI decreasing.

Materials and Methods:

We conducted a cohort study of 1388 patients who underwent cardiac surgery in one university hospital. A serum creatinine higher than 2 mg/dl, renal disease history, renal replacement therapy (chronic dialysis) were our exclusion criteria.

Results:

From our 1088 samples, 701 (64.43%) patients had normal kidney function, 277 (25.45%) were in the AKI-1 group, 84 (7.72%) had an AKI-2 function, and the rest of patients were classified as end stage. A mean of more than three PC units were transfused for the second and third stage of AKI, which was significantly higher than other AKI groups (P = 0.009); this higher demand of blood product was also true about the fresh frozen plasma, platelet, and fibrinogen. However, there were no needs of fibrinogen in the patients with normal kidney function. The cardiopulmonary bypass time had an average of 142 ± 24.12, which obviously was higher than other groups (P = 0.032). Total mortality rate was 14 out of 1088 (1.28%), and expiration among the AKI stages 2 and 3 was meaningfully (P = 0.001) more than the other groups.

Conclusion:

A more occurrence of AKI reported for the patients who have taken more units of blood. However, BC indicated to be safer for compensating blood loss because of low AKI occurrence among our patients.

Subcellular Energetics and Metabolism: Potential Therapeutic Applications

Part I of this review discussed the similarities between embryogenesis, mammalian adaptions to hypoxia (primarily driven by hypoxia-inducible factor-1 [HIF-1]), ischemia-reperfusion injury (and its relationship with reactive oxygen species), hibernation, diving animals, cancer, and sepsis, and it focused on the common characteristics that allow cells and organisms to survive in these states. Part II of this review describes techniques by which researchers gain insight into subcellular energetics and identify potential future tools for clinicians. In particular, P nuclear magnetic resonance to measure high-energy phosphates, serum lactate measurements, the use of near-infrared spectroscopy to measure the oxidation state of cytochrome aa3, and the ability of the protoporphyrin IX-triplet state lifetime technique to measure mitochondrial oxygen tension are discussed. In addition, this review discusses novel treatment strategies such as hyperbaric oxygen, preconditioning, exercise training, therapeutic gases, as well as inhibitors of HIF-1, HIF prolyl hydroxylase, and peroxisome proliferator-activated receptors.

Association of frailty status with acute kidney injury and mortality after transcatheter aortic valve replacement: A systematic review and meta-analysis

Objective

Frailty is a common condition in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR). The aim of this systematic review was to assess the impact of frailty status on acute kidney injury (AKI) and mortality after TAVR.

Methods

A systematic literature search was conducted using MEDLINE, EMBASE, and Cochrane databases from the inception through November 2016. The protocol for this study is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42016052350). Studies that reported odds ratios, relative risks or hazard ratios comparing the risk of AKI after TAVR in frail vs. non-frail patients were included. Mortality risk was evaluated among the studies that reported AKI-related outcomes. Pooled risk ratios (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

Results

Eight cohort studies with a total of 10,498 patients were identified and included in the meta-analysis. The pooled RR of AKI after TAVR among the frail patients was 1.19 (95% CI 0.97–1.46, I² = 0), compared with non-frail patients. When the meta-analysis was restricted only to studies with standardized AKI diagnosis according to Valve Academic Research Consortium (VARC)-2 criteria, the pooled RRs of AKI in frail patients was 1.16 (95% CI 0.91–1.47, I² = 0). Within the selected studies, frailty status was significantly associated with increased mortality (RR 2.01; 95% CI 1.44–2.80, I² = 58).

Conclusion

The findings from our study suggest no significant association between frailty status and AKI after TAVR. However, frailty status is associated with mortality after TAVR and may aid appropriate patient selection for TAVR.

Renin-Angiotensin System Inhibitor is Associated with Lower Risk of Ensuing Chronic Kidney Disease after Functional Recovery from Acute Kidney Injury

Acute kidney injury (AKI) is an independent risk factor for ensuing chronic kidney disease (CKD). Animal studies have demonstrated that renin-angiotensin system (RAS) inhibitor can reduce ensuing CKD after functional recovery from AKI. Here we study the association between ensuing CKD and use of RAS inhibitor including angiotensin converting enzyme inhibitor or angiotensin II type 1a receptor blocker starting after renal functional recovery in our prospectively collected observational AKI cohort. Adult patients who had cardiac surgery-associated AKI (CSA-AKI) are studied. Patients with CKD, unrecovered AKI, and use of RAS inhibitor before surgery are excluded. Among 587 eligible patients, 94 patients are users of RAS inhibitor which is started and continued after complete renal recovery during median follow-up period of 2.99 years. The users of RAS inhibitor show significantly lower rate of ensuing CKD (users vs. non-users, 26.6% vs. 42.2%) and longer median CKD-free survival time (users vs. non-users, 1079 days vs. 520 days). Multivariate Cox regression analyses further demonstrate that use of RAS inhibitor is independently associated with lower risk of ensuing CKD (hazard ratio = 0.46, P < 0.001). We conclude that use of RAS inhibitor in CSA-AKI patients after renal functional recovery is associated with lower risk of ensuing CKD development.

Age and Surgical Complexity impact on Renoprotection by Remote Ischemic Preconditioning during Adult Cardiac Surgery: A Meta analysis

We aimed to conduct an up-to-date meta-analysis to comprehensively assess the renoprotective effect of remote ischemic preconditioning (RIPC) in patients undergoing adult cardiac surgery. 21 randomized controlled trials (RCTs) with a total of 6302 patients were selected and identified. Compared with controls, RIPC significantly reduced the incidence of acute kidney injury (AKI) [odds ratio (OR) = 0.79; P = 0.02; I² = 38%], and in particular, AKI stage I (OR = 0.65; P = 0.01; I² = 55%). RIPC significantly shortened mechanical ventilation (MV) duration [weighted mean difference (WMD) = −0.79 hours; P = 0.002; I² = 53%), and reduced intensive care unit (ICU) stay (WMD = −0.23 days; P = 0.07; I² = 96%). Univariate meta-regression analyses showed that the major sources of heterogeneity for AKI stage I were age (coefficient = 0.06; P = 0.01; adjusted R2 = 0.86) and proportion of complex surgery (coefficient = 0.02; P = 0.03; adjusted R2 = 0.81). Subsequent multivariate regression and subgroup analyses also confirmed these results. The present meta-analysis suggests that RIPC reduces the incidence of AKI in adults undergoing cardiac surgery and this benefit was more pronounced in younger patients undergoing non-complex cardiac surgery. RIPC may also shorten MV duration and ICU stay. Future RCTs tailored for those most likely to benefit from RIPC warrants further investigation.

Obesity Increases Risk-Adjusted Morbidity, Mortality, and Cost Following Cardiac Surgery

BACKGROUND

Despite the epidemic rise in obesity, few studies have evaluated the effect of obesity on cost following cardiac surgery. We hypothesized that increasing body mass index (BMI) is associated with worse risk-adjusted outcomes and higher cost.

METHODS AND RESULTS

Medical records for 13 637 consecutive patients who underwent coronary artery bypass grafting (9702), aortic (1535) or mitral (837) valve surgery, and combined valve-coronary artery bypass grafting (1663) procedures were extracted from a regional Society of Thoracic Surgeons certified database. Patients were stratified by BMI: normal to overweight (BMI 18.5-30), obese (BMI 30-40), and morbidly obese (BMI >40). Differences in outcomes and cost were compared between BMI strata and also modeled as a continuous function of BMI with adjustment for preoperative risk using Society of Thoracic Surgeons predictive risk indices. Morbidly obese patients incurred nearly 60% greater observed mortality than normal weight patients. Moreover, morbidly obese patients had greater than 2-fold increase in renal failure and 6.5-fold increase in deep sternal wound infection. After risk adjustment, a significant association was found between BMI and mortality (P<0.001) and major morbidity (P<0.001). The risk-adjusted odds ratio for mortality for morbidly obese patients was 1.57 (P=0.02) compared to normal patients. Importantly, risk-adjusted total hospital cost increased with BMI, with 17.2% higher costs in morbidly obese patients.

CONCLUSIONS

Higher BMI is associated with increased mortality, major morbidity, and cost for hospital care. As such, BMI should be more strongly considered in risk assessment and resource allocation.

Effects of continuous renal replacement therapy on serum cytokines, neutrophil gelatinase-associated lipocalin, and prognosis in patients with severe acute kidney injury after cardiac surgery

The aim of our study was to evaluate the effect of continuous renal replacement therapy (CRRT) on serum cytokines, neutrophil gelatinase-associated lipocalin (NGAL), and prognosis in patients with severe acute kidney injury (AKI) following cardiac surgery. A total number of 153 patients with severe AKI following cardiac surgery were treated with CRRT. They were divided into the survival and non-survival groups. Clinical data from these two groups before and after CRRT were recorded and analyzed. It was found that the number of impaired organs, MODS and APACHE II scores were significantly higher in the non-survival group than those in the survival group before CRRT. After CRRT, MODS and APACHE II scores decreased significantly. The post-CRRT levels of serum TNF-a and IL-6 were significantly decreased. After CRRT, serum NGAL decreased in the two groups, but the levels were higher in the non-survival group than those in the survival group. MODS and APACHE II scores could be used to evaluate the severity of AKI in patients after cardiac surgery. CRRT is an effective treatment for these patients and high levels of TNF-a, IL-6, and NGAL are associated with a poor prognosis in these patients.

Recent Perioperative Pharmacological Prevention of Acute Kidney Injury after Cardiac Surgery: A Narrative Review

Acute kidney injury (AKI) is a common and severe complication of cardiac surgery, and related rates of both hospitalization and long-term mortality are increasing. A number of studies have explored the preventive effects of perioperative pharmacological therapy on AKI after cardiac surgery. However, the mechanisms of AKI are multifaceted, and no universal treatment has been confirmed as beneficial. We review and analyze several current perioperative pharmacological therapies for AKI after cardiac surgery to identify promising preventive strategies.

Acute Kidney Injury and In-Hospital Mortality after Coronary Artery Bypass Graft versus Percutaneous Coronary Intervention: A Nationwide Study

BACKGROUND

Post-procedural acute kidney injury (AKI) is associated with significantly increased short- and long-term mortalities, and renal loss. Few studies have compared the incidence of post-procedural AKI and in-hospital mortality between 2 major modalities of revascularization - coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) - and results have been inconsistent.

METHODS

We generated a propensity score-matched cohort that includes a total of 286,670 hospitalizations with multi-vessel coronary disease undergoing CABG or PCI (2004-2012) from the National Inpatient Sample database. We compared incidence of AKI, AKI requiring renal replacement therapy (RRT), in-hospital mortality, hospital stay, and charges between CABG and PCI groups.

RESULTS

The incidence of AKI after CABG was higher than PCI (8.9 vs. 4.5%, OR 2.05, 95% CI 1.99-2.12, p < 0.001). The incidence of AKI requiring RRT was also higher after CABG (1.1 vs. 0.5%, OR 2.14, 95% CI 1.96-2.34, p < 0.001). Likewise, in-hospital mortality was higher after CABG than PCI (2.0 vs. 1.4%, OR 1.44, 95% CI 1.35-1.52, p < 0.001). Among patients with pre-existing chronic kidney disease (stages I-IV), those undergoing CABG was associated with 2.0-2.3-fold higher odds of developing AKI than those undergoing PCI. The patients treated with CABG had a significantly longer hospital stay and higher hospital charges.

CONCLUSIONS

Patients undergoing CABG are associated with (1) increased risk of developing post-procedural AKI, (2) higher likelihood of receiving RRT, and (3) worse short-term survival. Long-term renal outcome remains to be studied.

Nerolidol Protects Against LPS-induced Acute Kidney Injury via Inhibiting TLR4/NF-κB Signaling

Acute kidney injury (AKI) is a critical care syndrome, resulting in acute reduction of renal function and up to 22% mortality of hospitalized patients. Nerolidol is a major component in several essential oils that possesses various pharmacological properties. The present study aimed to investigate the potential effect of nerolidol on lipopolysaccharide (LPS)-induced AKI. Nerolidol dose-dependently reduced the pathological injuries of kidney induced by LPS in rats. Nerolidol significantly decreased the levels of blood urea nitrogen and creatinine in LPS-treated rats in a dose-dependent manner. In addition, nerolidol inhibited LPS-induced decrease of cell viability in NRK-52E rat proximal tubular cells, which effect was concentration dependent. Nerolidol notably inhibited the increase of TNFα and IL-1β in LPS-treated rats and the mRNA expression of TNFα and IL-1β in LPS-treated NRK-52E cells. Nerolidol suppressed the increase of toll-like receptor 4 (TLR4) expression, phosphorylation and nuclear translocation of p65 NF-κB in kidneys of LPS-treated rats and LPS-treated NRK-52E cells. Overexpression of TLR4 and p65 NF-κB significantly suppressed nerolidol-induced inhibition of TNFα and IL-1β expression and increase of cell viability in LPS-treated cells. In summary, we found that nerolidol played a critical anti-inflammatory effects through inhibition of TLR4/NF-κB signaling and protected against LPS-induced AKI. Copyright © 2017 John Wiley & Sons, Ltd.

Prophylactic orthosteric inhibition of leukocyte integrin CD11b/CD18 prevents long-term fibrotic kidney failure in cynomolgus monkeys

Ischaemic acute kidney injury (AKI), an inflammatory disease process, often progresses to chronic kidney disease (CKD), with no available effective prophylaxis. This is in part due to lack of clinically relevant CKD models in non-human primates. Here we demonstrate that inhibition of the archetypal innate immune receptor CD11b/CD18 prevents progression of AKI to CKD in cynomolgus monkeys. Severe ischaemia-reperfusion injury of the right kidney, with subsequent periods of the left ureter ligation, causes irreversible right kidney failure 3, 6 or 9 months after AKI. Moreover, prophylactic inactivation of CD11b/CD18, using the orthosteric CD11b/CD18 inhibitor mAb107, improves microvascular perfusion and histopathology, reduces intrarenal pro-inflammatory mediators and salvages kidney function long term. These studies reveal an important early role of CD11b⁺ leukocytes in post-ischaemic kidney fibrosis and failure, and suggest a potential early therapeutic intervention to mitigate progression of ischaemic AKI to CKD in humans.

Reassessment of Acute Kidney Injury after Cardiac Surgery: A Retrospective Study

Objective To evaluate the incidence, risk, or protective factors of acute kidney injury (AKI) in patients after cardiac surgery based on the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Methods A retrospective analysis of 2,575 patients undergoing their first documented cardiac surgery with cardiopulmonary bypass (CPB) was conducted. Perioperative variables were collected and analyzed. Univariate and multiple logistic regression models were used for determining the association between the development of AKI and risk factors. Multiple Cox-proportional hazards modeling was performed to evaluate the impact of AKI on the mortality in the intensive care unit and hospital length of stay. Results Of 2,575 patients, 931 (36%) developed AKI. A total of 30 (1.2%) patients required renal replacement therapy. In the multivariate analysis, mechanical ventilation duration (OR1.446, 95% CI 1.195-1.749, p<0.001), CPB duration of ≥110 min (OR 1.314, 95% CI 1.072-1.611, p=0.009), erythrocytes transfusion (OR 1.078, 95% CI 1.050-1.106, p<0.001), and postoperative body temperature greater than 38°C within 3 days (OR 1.234, 95% CI 1.018-1.496, p=0.032) were independent risk factors for CSA-AKI, while ulinastatin use was associated with a reduced incidence of CSA-AKI (OR 0.694, 95% CI 0.557-0.881, p=0.006). CSA-AKI was significantly associated with in-hospital mortality (adjusted HR: 2.218, 95% CI 1.161-4.238, p=0.016), especially in patients needing renal replacement therapy (adjusted HR: 18.683, 95% CI 8.579-40.684, p<0.001). Conclusion Mechanical ventilation duration, erythrocytes transfusion, and postoperative body temperature above 38°C within 3 days were considered independent risk factors for CSA-AKI. The use of ulinastatin was associated with a reduced incidence of CSA-AKI.

Effects of low-dose atrial natriuretic peptide infusion on cardiac surgery-associated acute kidney injury: A multicenter randomized controlled trial

PURPOSE

To evaluate the effects of atrial natriuretic peptide (ANP) on renal function and medical costs in patients with acute kidney injury (AKI) associated with cardiac surgery.

MATERIALS AND METHODS

The Japanese trial for AKI in Post-cardiovascular surgery patients by ANP (JAPAN) was a prospective, multicenter, randomized, double-blind, placebo-controlled study conducted in 11 hospitals in Japan. Acute kidney injury was defined as an increase in serum creatinine of at least 0.3 mg/dL within 48 hours. The patients were randomly assigned to receive ANP (0.02 μg kg^-1 min^-1) or placebo. The primary end point was a change in renal function. The secondary end points were a need for renal replacement therapy, the lengths of intensive care unit and hospital stays, and medical costs incurred over the 90-day follow-up.

RESULTS

Of the 77 randomized patients, 37 were in the ANP group and 40 were in the placebo group. Although ANP significantly (P = .018) increased urine output, it did not significantly improve renal function compared with placebo. There were no significant differences between the groups in the renal replacement therapy rate, the lengths of the intensive care unit and hospital stays, or medical costs.

CONCLUSION

Atrial natriuretic peptide infusion did not show a renoprotective effect or cost-saving effect in the treatment of cardiac surgery-associated AKI.

Sex and the Risk of AKI Following Cardio-thoracic Surgery: A Meta-Analysis

BACKGROUND AND OBJECTIVES

Being a woman is a well established risk factor for the development of cardiothoracic surgery-associated AKI. In striking contrast, women are less likely to develop AKI associated with noncardiac surgical procedures than men. In an attempt to ascertain why being a woman might be protective for ischemic AKI after general surgery but deleterious in patients undergoing cardiothoracic surgery, we examined cardiothoracic surgery-associated AKI in greater detail.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a systematic review and meta-analysis of cardiothoracic surgery-associated AKI studies published between January of 1978 and December of 2015 to further explore the relationship between sex and cardiothoracic surgery-associated AKI.

RESULTS

Sixty-four studies were identified that provided sex-specific data regarding the incidence of cardiothoracic surgery-associated AKI among 1,057,412 subjects. Using univariate analysis, women were more likely than men to develop AKI postoperatively (odds ratio, 1.21; 95% confidence interval, 1.09 to 1.33; P<0.001). However, when the analysis was restricted to the 120,464 subjects reported in 29 studies that used the Acute Kidney Injury Network criteria, the RIFLE criteria, or the Kidney Disease Improving Global Outcomes criteria to define AKI, there was no significant sex-related difference in risk. Seventeen studies used multivariate analysis to assess risk factors for cardiothoracic surgery-associated AKI and provided sex-specific odd ratios. Among the 1,587,181 individuals included in these studies, the risk of developing cardiothoracic surgery-associated AKI was not significantly associated with sex (odds ratio, 1.04; 95% confidence interval, 0.92 to 1.19; P=0.51). However, when the analysis was restricted to the 5106 subjects reported in four studies that used the Acute Kidney Injury Network criteria to define AKI, the risk of developing AKI was significantly lower in women compared with in men (odds ratio, 0.75; 95% confidence interval, 0.65 to 0.87; P<0.001).

CONCLUSIONS

Our systematic review and meta-analysis contradict the generally held consensus that being a woman is an independent risk factor for the development of cardiothoracic surgery-associated AKI.

Impact of balanced tetrastarch raw material on perioperative blood loss: a randomized double blind controlled trial

BACKGROUND

As 6% hydroxyethyl starch (HES) 130/0.40 or 130/0.42 can originate from different vegetable sources, they might have different clinical effects. The purpose of this prospective, randomized, double-blind controlled trial was to compare two balanced tetrastarch solutions, one maize-derived and one potato-derived, on perioperative blood loss in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

We randomly assigned 118 patients undergoing elective cardiac surgery into two groups, to receive either a maize- or a potato-derived HES solution. Study fluids were administered perioperatively (including priming of CPB) until the second postoperative day (POD#2) using a goal directed algorithm. The primary outcome was calculated postoperative blood loss up to POD#2. Secondary outcomes included short-term incidence of acute kidney injury (AKI), and long-term effect (up to one yr) on renal function.

RESULTS

Preoperative and intraoperative characteristics of the subjects were similar between groups. Similar volumes of HES were administered (1950 ml [1250-2325] for maize-HES and 2000 ml [1500-2700] for potato-HES; P=0.204). Calculated blood loss (504 ml [413-672] for maize-HES vs 530 ml [468-705] for potato-HES; P=0.107) and the need for blood components were not different between groups. The incidence of AKI was similar in both groups (P=0.111). Plasma creatinine concentration and glomerular filtration rates did vary over time, although changes were minimal.

CONCLUSIONS

Under our study conditions, HES 130/0.4 or 130/0.42 raw material did not have a significant influence on perioperative blood loss. Moreover, we did not find any effect of tetrastarch raw material composition on short and long-term renal function.

CLINICAL TRIAL REGISTRATION

EudraCT number: 2011-005920-16.

A BMI >35 does not protect patients undergoing cardiac bypass surgery from red blood cell transfusion

The effect of obesity on allogeneic intraoperative blood product transfusion in patients undergoing coronary artery bypass graft surgery (CABG) is poorly understood. We analyzed the influence of obesity on the risk of intraoperative red blood cell (RBC) transfusion among 45,200 consecutive non-reoperative CABG procedures from a multi-institutional perfusion database. A body mass index (BMI) in obese I category was associated with a 9.9% decrease in transfusion risk (p<0.05). Compared to patients with a normal BMI, obese I and obese III patients do not have any change in the relative risk of RBC transfusion. Overweight and mild obesity have a protective role in reducing intraoperative blood transfusion during cardiopulmonary bypass (CPB) surgery. However, logistic regression analysis showed that much of the observed reduction in transfusion rates for obese patients can be accounted for by other known confounds. The lack of a linear effect of increasing BMI on blood transfusion risk is a novel finding and warrants further investigation.

A comparison of preemptive versus standard renal replacement therapy for acute kidney injury after cardiac surgery

BACKGROUND

The optimal timing of renal replacement therapy (RRT) initiation in patients undergoing cardiac surgery remains controversial. This study aimed to determine whether preemptive RRT or standard RRT was associated with hospital mortality in cardiac surgical patients with acute kidney injury (AKI).

METHODS

Data were retrospectively collected from patients who underwent cardiac surgery and experienced postoperative AKI requiring RRT at Zhongshan Hospital of Fudan University from September 1, 2006 to December 31, 2013. The patients were divided into two groups according to the RRT strategy applied.

RESULTS

A total of 213 patients were enrolled in this study; 59 patients were categorized into the preemptive RRT group and 154 into the standard RRT group. The preemptive RRT group exhibited significantly lower mortality (33.90% versus 51.95%, P = 0.018) and time to recovery of renal function than the standard RRT group (15.34 ± 14.46 versus 22.88 ± 14.08 d, P = 0.022). Moreover, the preemptive RRT group showed significantly lower serum creatinine levels and higher proportions of recovery of renal function and weaning from RRT at death or discharge than the standard RRT group. There was no significant difference in the duration of mechanical ventilation, RRT, intensive care unit stay, or hospital stay between the two groups.

CONCLUSIONS

In patients after cardiac surgery, preemptive RRT was associated with lower hospital mortality and faster and more frequent recovery of renal function than standard RRT. However, preemptive RRT did not affect other patient-centered outcomes including mechanical ventilation time, RRT time, or length of intensive care unit or hospital stay.

Comparison of three early biomarkers for acute kidney injury after cardiac surgery under cardiopulmonary bypass

Background

Acute kidney injury (AKI) is a serious complication after cardiac surgery, being associated with a high mortality. We assessed three urinary biomarkers, L-type fatty acid-binding protein (L-FABP), neutrophil gelatinase-associated lipocalin (NGAL), and angiotensinogen, which are elevated through different mechanisms, and investigated which of these biomarkers was the earliest and most useful indicator of AKI after cardiac surgery.

Methods

This study was a prospective observational study conducted at a single-institution university hospital. All patients were adults aged under 80 years who underwent cardiac surgery with cardiopulmonary bypass between November 2013 and January 2015. Perioperatively, urine samples were obtained from all patients at five points. Based on AKI criteria, patients were divided into two groups: AKI group (n = 11) and non-AKI group (n = 39), according to postoperative serum creatinine (Cr) levels.

Results

Urinary L-FABP, NGAL, angiotensinogen, and Cr were measured perioperatively. L-FABP was significantly higher in the AKI group than in the non-AKI group at the end of surgery and 3 h after surgery. L-FABP levels were 601.5 ± 341.7 and 233.8 ± 127.2 μg/g Cr in the AKI and non-AKI groups, respectively. Three hours after surgery, NGAL levels were 950.5 ± 827.9 and 430.0 ± 250.6 μg/g Cr in the AKI and non-AKI groups, respectively, the level being significantly higher in the AKI group than in the non-AKI group. There were no significant differences in urinary angiotensinogen levels between the two groups at any time point.

Conclusions

We demonstrated the utility of L-FABP and NGAL, but not angiotensinogen in the early recognition of AKI. The problem of the different peak points among biomarkers needs to be resolved for discovery of a panel of biomarkers.

Early detection of acute kidney injury after pediatric cardiac surgery

Acute kidney injury (AKI) is increasingly recognized as a common problem in children undergoing cardiac surgery, with well documented increases in morbidity and mortality in both the short and the long term. Traditional approaches to the identification of AKI such as changes in serum creatinine have revealed a large incidence in this population with significant negative impact on clinical outcomes. However, the traditional diagnostic approaches to AKI diagnosis have inherent limitations that may lead to under-diagnosis of this pathologic process. There is a dearth of randomized controlled trials for the prevention and treatment of AKI associated with cardiac surgery, at least in part due to the paucity of early predictive biomarkers. Novel non-invasive biomarkers have ushered in a new era that allows for earlier detection of AKI. With these new diagnostic tools, a more consistent approach can be employed across centers that may facilitate a more accurate representation of the actual prevalence of AKI and more importantly, clinical investigation that may minimize the occurrence of AKI following pediatric cardiac surgery. A thoughtful management approach is necessary to mitigate the effects of AKI after cardiac surgery, which is best accomplished in close collaboration with pediatric nephrologists. Long-term surveillance for improvement in kidney function and potential development of chronic kidney disease should also be a part of the comprehensive management strategy.

Acute kidney injury after cardiovascular surgery

Acute kidney injury (AKI) is a complication experienced by many patients undergoing cardiovascular surgery. Postoperative deterioration in renal function is associated with an increased risk of in-hospital mortality and affects long-term survival. Developing strategies to identify and treat AKI is important to reduce incidence and optimize outcomes.

Clinical Use of the Urine Biomarker [TIMP-2] × [IGFBP7] for Acute Kidney Injury Risk Assessment

Acute kidney injury (AKI) is a serious complication, commonly occurring in the critically ill population, with devastating short- and long-term consequences. Despite standardization of the definition and staging of AKI, early recognition remains challenging given that serum creatinine level is a marker, albeit imperfect, of kidney function and not kidney injury. Furthermore, the delay in increase in serum creatinine level after loss of glomerular filtration also prevents timely detection of decreased kidney function in patients with AKI. During the past decade, numerous clinical investigations have evaluated the utility of several biomarkers in the early diagnosis and risk stratification of AKI. In 2014, the US Food and Drug Administration approved the marketing of a test based on the combination of urine concentrations of tissue inhibitor of metalloproteinase 2 and insulin-like growth factor binding protein 7 ([TIMP-2] × [IGFBP7]) to determine whether certain critically ill patients are at risk for developing moderate to severe AKI. The optimal role of this biomarker in the diagnosis, management, and prognosis of AKI in different clinical settings requires further clarification. In this perspective, we summarize the biological actions of these 2 cell-cycle arrest biomarkers and present important considerations regarding the clinical application, interpretation, and limitations of this novel test for the early detection of AKI.

Ulinastatin administration is associated with a lower incidence of acute kidney injury after cardiac surgery: a propensity score matched study

BACKGROUND

Systemic inflammation is involved in the development of acute kidney injury (AKI) after cardiac surgery with cardiopulmonary bypass (CPB). Ulinastatin, a urinary trypsin inhibitor (UTI), possesses a variety of anti-inflammatory effects. Therefore, we hypothesized that the administration of ulinastatin would reduce the occurrence of AKI in patients undergoing cardiac surgery with CPB.

METHODS

A retrospective propensity score matched analysis was used to evaluate the effect of ulinastatin on the development of AKI in patients undergoing first documented cardiac surgery with CPB between January 2008 and December 2012 in our hospital. Multiple logistic regression models were also employed to identify the association between UTI administration and development of AKI.

RESULTS

A total of 2072 patients who underwent cardiac surgery with CPB met the inclusion criteria. Before propensity score matching, variables such as age, baseline creatinine, CPB duration, red blood cells transfused, and hematocrit were statistically different between the ulinastatin (UTI) group and the control group. On the basis of propensity scores, 409 UTI patients were successfully matched to the 409 patients from among those 1663 patients without UTI administration. After propensity score matching, no statistically significant differences in the baseline characteristics were found between the UTI group and the control group. The propensity score matched cohort analysis revealed that AKI and the need for renal replacement therapy occurred more frequently in the control group than in the UTI group (40.83% vs. 30.32%, P = 0.002; 2.44% vs. 0.49%, P = 0.02, respectively). However, there were no significant differences in mortality, length of intensive care unit stay, and length of hospital stay between the UTI group and the control group. Using multivariate logistic regression analysis, we found ulinastatin played a protective role in the development of AKI after cardiac surgery (odds ratio 0.71, 95% confidence interval 0.56-0.90, P = 0.005).

CONCLUSIONS

This study shows that ulinastatin was associated with a lower incidence of AKI after cardiac surgery, suggesting that the administration of ulinastatin may be favorable for those patients undergoing cardiac surgery with CPB.

Incidence and mortality of postoperative acute kidney injury in non-dialysis patients: comparison between the AKIN and KDIGO criteria

OBJECTIVES

This retrospective study determines whether the kidney disease: improving global outcomes (KDIGO) criteria are superior to acute kidney injury network (AKIN) criteria in detecting non-dialysis AKI events and predicting mortality in chronic kidney disease (CKD) patients after surgery.

METHODS

Surgical patients who were admitted to the intensive care unit were enrolled. Non-dialysis AKI cases were defined using either KDIGO or AKIN creatinine criteria and stratified by CKD stages. The adjusted hazard ratios (AHRs) for in-hospital mortality are compared to those without AKI. The cumulative survival curves and the predictability for mortality are accessed by Kaplan-Meier method and calculating the area under the curve (AUC) for the receiver operating characteristic (ROC) curve, respectively.

RESULTS

From a total of 826 postoperative patients, the overall in-hospital mortality rate was 11.6% (96 cases) and that for AKI according to KDIGO and AKIN criteria was 30.0% (248 cases) and 31.0% (256 cases). The cumulative survival curve stratified by CKD and AKI stages were comparable between KDIGO and AKIN criteria. The discriminative power for mortality stratified by CKD stages for KDIGO and AKIN criteria are as followed: all subjects: 0.678 versus 0.670 (both ps <0.001); non-CKD: 0.800 versus 0.809 (both ps <0.001); early-stage CKD: 0.676 versus 0.676 (both ps <0.001); late-stage CKD: 0.674 versus 0.660 (ps were <0.001 and 0.003).

CONCLUSION

The KDIGO criteria are superior to AKIN criteria in predicting mortality after surgery, especially in those with advanced CKD.

[Neuroprotective and nephroprotective effects of remote postconditioning: Prospects for clinical use]

The results of experimental and clinical studies strongly suggest that remote ischemic preconditioning (RIP) has no neuroprotective effect during cardiac surgery performed under extracorporeal circulation. Remote preconditioning (RP) has no neuroprotective effect in hemorrhagic stroke. A randomized multicenter study is needed to evaluate the efficiency RIP in patients with ischemic stroke. RP reduces the severity of ischemia/reperfusion kidney injury during transplantation. RIP has been established to prevent contrast-induced nephropathy. There is a need for a multicenter trial to evaluate the efficiency of RIP in patients with abdominal aortic aneurysm repair. Analysis of the presented data indicates that RIP fails to prevent cardiorenal syndrome in infants and children during cardiac surgery. The data available in the literature on the capacity of RIP to provide nephroprotective effect in patients after coronary artery bypass surgery are discordant and indicative of the advisability of a multicenter study.