Preoperative use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers is associated with increased risk for acute kidney injury after cardiovascular surgery

Pilot study to develop a pre-operative "Cardiothoracic Clinical Handover Tool" and its effect on handover quality

BACKGROUND

Clinical handover is an essential step in the surgical patient's hospital journey, but one that is not without risk. Within cardiothoracic surgery, endeavours to protocolise post-operative handover from cardiac theatre to cardiac intensive care units have resulted in enhanced patient safety, but little to no effort has focused on the pre-operative setting and the dissemination of information throughout the surgical team.

METHODS

We designed a pre-post study examining the quality of pre-operative cardiothoracic patient handovers before and after the introduction of an intra-departmentally designed "Cardiothoracic Clinical Handover Tool" based on the Royal College of Surgeons of England's guidelines for "Safe Handover".

RESULTS

Forty clinical handovers were assessed in each arm of the study. Handover quality improved from a score of 63.75% to 88.57% (p = < 0.001). This prolonged handover duration from a mean of 72.1 to 102.4 seconds per case (p = 0.003). Interruptions occurred in 27.5% of pre- and 25% of post-intervention handovers. Interruptions resulted in increased handover duration in both pre- and post-intervention groups (114.6 vs 77.7 seconds, p = 0.012) and poorer quality handovers in the pre-intervention group (51.28% vs 68.42%, p = 0.03) but failed to impact handover quality in the post-intervention group (88.57% vs 88.57%, p = 1).

CONCLUSIONS

Clinical handover tools have the potential to enhance the quality of pre-operative handover and protect against poor handover practices such as interruptions, safe-guarding patient welfare. We provide the first cardiothoracic specific pre-operative handover tool based on the RCSE guidelines.

Acute Kidney Injury After Total Hip and Knee Arthroplasty. What Is the Culprit?

Background

Acute kidney injury (AKI) is associated with increased complications after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The purpose of this study was to determine the risk factors for AKI after THA and TKA and evaluate if preoperative use of antihypertensive drugs is a risk factor for AKI.

Methods

A retrospective review of 7406 primary TKAs and THAs (4532 hips and 2874 knees) from 2013 to 2019 was performed. The following preoperative variables were obtained from medical records: medications, chemistry 7 panel, Elixhauser comorbidities, and demographic factors. AKI was defined as an increase in serum creatinine by 26.4 μmol·L-1. Multivariate analysis was performed to identify the risk factors.

Results

The overall incidence of postoperative AKI was 6.2% (n = 459). Risk factors for postoperative AKI were found to be: chronic kidney disease (odds ratio [OR] = 7.09; 95% confidence interval [CI]: 4.8-9.4), diabetes (OR: 5.03; 95% CI: 2.8-6.06), ≥3 antihypertensive drugs (OR: 4.2; 95% CI: 2.1-6.2), preoperative use of an angiotensin receptor blockers or angiotensin-converting enzyme inhibitors (OR: 3.8; 95% CI: 2.2-5.9), perioperative vancomycin (OR: 2.7; 95% CI: 1.8-4.6), and body mass index >40 kg/m2 (OR: 1.9; 95% CI: 1.3-3.06).

Conclusions

We have identified several modifiable risk factors for AKI that can be optimized prior to an elective THA or TKA. The use of certain antihypertensive agents namely angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and multidrug antihypertensive regimens were found to significantly increase the risk of AKI. Therefore, perioperative management of patients undergoing joint replacement should include medical comanagement with a focus on careful management of antihypertensives.

The Renin-Angiotensin System Involvement in Cisplatin-Induced Nephrotoxicity: An Overview of Physiological and Pathological Mechanisms-A Systematic Review

Cisplatin (CDDP) is a highly potent chemotherapy drug. But its nephrotoxicity poses a significant limitation to its use. The renin-angiotensin system (RAS) has been proposed to play a role in drug-induced nephrotoxicity. This systematic review (SR) sought to identify the link between CDDP-induced nephrotoxicity and the RAS pathway. In this SR, relevant keywords were employed to explore databases such as PubMed (MEDLINE), Scopus (Elsevier), and Institute for Scientific Information (ISI) Web of Science up to October 2023. Nine studies were selected based on predefined inclusion/exclusion criteria. The findings support the involvement of the RAS in the CDDP-induced nephrotoxicity model, along with the activation of inflammatory mediators, lipid peroxidation, and changes in markers of kidney tissue damage. Furthermore, physiology and pathology of RAS-related interventions in CDDP-induced nephrotoxicity models have involved the factors such as human organic cation transporter 2 (hOCT2), organic anion transporting polypeptides 1B1 (OATP1B1) and 1B3, kallikrein-kinin system, and bradykinin receptors. CDDP-induced nephrotoxicity has been found to be substantially influenced by both classic and nonclassic RAS axes. Angiotensin II exacerbates renal damage induced by CDDP. Conversely, inhibiting the pressor arm of RAS in males mitigates this damage. However, activation of the renal vasodepressor arm of RAS exacerbates CDDP-induced nephrotoxicity in females. These findings underscore gender differences in renal function and response to RAS-related interventions in the presence of CDDP. This SR provides insights into both beneficial and adverse interventions associated with RAS in the CDDP-induced nephrotoxicity, offering valuable considerations for researchers and clinicians.

The association of withholding or continuing angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers on acute kidney injury after non-cardiac surgery

BACKGROUND

Withholding or continuing angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers peri-operatively in non-cardiac surgery remains controversial as they may result in intra-operative hypotension and postoperative organ damage.

METHODS

We included patients prescribed angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers who underwent surgical procedures > 1 h duration under general or spinal anaesthesia from January 2012 to June 2022 in a single centre. We categorised patients by whether these drugs were withheld for 24 h before surgery. We evaluated the association of withholding these drugs before non-cardiac surgery with creatinine concentrations that increased ≥ 26.4 μmol.l-1 in the first 48 postoperative hours (acute kidney injury). We also analysed changes in creatinine concentrations and estimated glomerular filtration rates.

RESULTS

Angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers were withheld in 24,285 of 32,933 (74%) patients and continued in 8648 (26%) patients. We used propensity scores for drug discontinuation to match 8631 patient pairs who did or did not continue these drugs: acute kidney injury was recorded for 1791 (21%) patients who continued these drugs vs. 1587 (18%) who did not (OR (95%CI) 1.16 (1.08-1.25), p < 0.001). Intra-operative hypotension was recorded for 3892 (45%) patients who continued drugs vs. 3373 (39%) patients who did not (OR (95%CI) 1.28 (1.21-1.36), p < 0.001). Continuing drugs was independently associated with a mean increase in creatinine of 2.2 μmol.l-1 (p < 0.001) and a mean decrease in estimated glomerular filtration rate of 1.4 ml.min.1.73 m-2 (p < 0.001).

CONCLUSIONS

Continuing angiotensin-converting enzyme inhibitors or angiotensin 2 receptor blockers 24 h before non-cardiac surgery was associated with intra-operative hypotension and postoperative acute kidney injury.

Hemodynamic effects of withholding vs. continuing angiotensin II receptor blockers on the day of prone positioning spinal surgery in elderly patients

Introduction

The hemodynamic effects of withholding vs. continuing angiotensin II receptor blockers (ARBs) before surgery in elderly patients undergoing spinal surgery in a prone position during anesthesia induction to skin incision are still unknown.

Methods

In this prospective study, 80 patients undergoing spinal surgery in a prone position with general anesthesia, aged 60-79 years, American Society of Anesthesiologists (ASA) II or III, were enrolled. Patients who had ARBs only in their preoperative medication list were randomly divided into two groups at a 1:1 ratio: In Group A, ARBs were continued on the morning of surgery, while in Group B, they were withhold. Norepinephrine was infused to maintain the blood pressure at the baseline level of ±20% during anesthesia induction in all patients. The primary outcome was the consumption of norepinephrine in each group from anesthesia induction to skin incision. The secondary outcomes include changes in invasive arterial blood pressure and heart rate, the fluid infusion volumes, the amounts of anesthetic drugs, and the total time from induction to skin incision.

Results

There were no significant differences in the demographics, the fluid infusion volumes, the amounts of anesthetic drugs, the total time from induction to skin incision, and hemodynamics at different time points (p > 0.05), while significant differences were found in norepinephrine consumption between the two groups (p < 0.001). Compared with Group B, the consumption of norepinephrine increased significantly in Group A (93.3 ± 29.8 vs. 124.1 ± 38.7 μg, p = 0.000). In addition, the same trend was illustrated in the pumping rate of norepinephrine between Group B (0.04 ± 0.01 μg·kg-1·min-1) and Group A (0.06 ± 0.02 μg·kg-1·min-1) (p = 0.004).

Conclusion

Our study conducted in elderly patients with hypotension undergoing prone spinal surgery demonstrated a greater pumping rate of norepinephrine during anesthesia induction in patients with ARBs continuing before surgery than those withholding, indicating that it was more difficult to maintain hemodynamic stability.Clinical Trial Registration: https://www.chictr.org.cn/showproj.html?proj=141081, ChiCTR2100053583.

Effect of pre-transplantation use of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in kidney transplant recipients-propensity score-matched analysis

BACKGROUND

Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ACEi/ARBs) can cause acute kidney injury under dehydratation or in hemodynamically unstable conditions. Regarding kidney transplantation (KT), the risk of using ACEi/ARBs before surgery is not well established. Therefore, we evaluated the clinical outcomes to determine the effect of preoperative use of ACEi/ARBs on KT.

METHODS

We retrospectively collected 1187 patients who received living-donor KT between January 2017 and December 2021. We conducted a propensity score-matched analysis between the ACEi/ARB(+) and ACEi/ARB(-) groups and evaluated the effects of ACEi/ARBs on delayed graft function, post-KT renal function, hyperkalemia events, rejection, and graft survival.

RESULTS

The ACEi/ARB(+) group showed a similar incidence of delayed graft function as the ACEi/ARB(-) group (1.8% vs. 1.0%, P = 0.362). The risk of delayed graft function was not upregulated in the ACEi/ARB(+) group after propensity score-matching (odds ratio: 0.50, 95% confidence interval (CI) 0.13-2.00). Postoperative creatinine levels and the slope of creatinine levels after KT also were not significantly different between the two groups (creatinine slope from POD#0 to POD#7: - 0.73 ± 0.35 vs. - 0.75 ± 0.32 mg/dL/day, P = 0.464). Hyperkalemia did not occur more often in the ACEi/ARB(+) group than in the ACEi/ARB(-) group during perioperative days. Rejection-free survival (P = 0.920) and graft survival (P = 0.621) were not significantly different between the two groups.

CONCLUSIONS

In KT, the preoperative use of ACEi/ARBs did not significantly affect clinical outcomes including delayed graft function, postoperative renal function, hyperkalemia events, incidence of rejection, and graft survival rates compared to the patients who did not receive ACEi/ARBs.

An online-predictive model of acute kidney injury after pancreatic surgery

OBJECTIVE

Acute kidney injury(AKI) after pancreatic surgery is associated with increased mortality, longer hospital stays and poor prognosis. This study aims to identify the risk factors and establish an easy-to-use prediction calculator by the nomogram to predict the risk of AKI after pancreatic surgery.

METHODS

From January 2016 to June 2018, 1504 patients who underwent pancreatic surgery in our center were included in this retrospective analysis and randomly assigned to primary (1054 patients) and validation (450 patients) cohorts. The independent risk factors of AKI were identified using univariate and multivariate analyses. A risk-predicted nomogram for AKI was developed through multivariate logistic regression analysis in the primary cohort while the nomogram was evaluated in the validation cohort. Nomogram discrimination and calibration were assessed using C-index and calibration curves in the primary and validation cohorts. The clinical utility of the final nomogram was evaluated using decision curve analysis.

RESULTS

The overall incidence of AKI after pancreatic surgery was 5.3% (79/1504). Independent risk factors including smoking history, cardiovascular disease, ASA score, baseline eGFR, bilirubin＞2 ​mg/dL, undergoing pancreaticoduodenectomy, and intraoperative blood loss＞400 ​mL were identified by multivariate analysis. Nomogram revealed moderate discrimination and calibration in estimating the risk of AKI, with an unadjusted C-index of 0.79 (95 %CI, 0.73-0.85). Application of the nomogram in the validation cohort provided moderate discrimination (C-index,0.80 [95% CI, 0.72-0.88]) and good calibration. Besides, the decision curve analysis (DCA) confirmed the clinical usefulness of the nomogram.

CONCLUSIONS

An easy-to-use online prediction calculator comprised of preoperative and intraoperative factors was able to individually predict the occurrence risk of AKI among patients with pancreatic surgery, which may help identify reasonable risk judgments and develop proper treatment strategies to a certain extent.

Predictors of acute kidney injury after lung resection surgery: a retrospective case-control study

PURPOSE

Patients undergoing lung resection are at increased risk for acute kidney injury (AKI) in the immediate postoperative period, with important consequences for longer term morbidity and mortality. Lung resection surgery has unique considerations that could increase the risk of AKI, including lung resection volume, duration of one-lung ventilation (OLV), and intraoperative fluid restriction. Yet, specific risk factor data are lacking. The objective of this study was to identify independent risk factors for early AKI after lung resection surgery.

METHODS

We conducted a retrospective case-control study of all patients presenting for elective lung resection surgery at an academic medical centre over a four-year period. Cases were patients who experienced an AKI and control patients were those who did not experience an AKI, based on KDIGO criteria. Baseline demographics and comorbidities along with duration of OLV and amount of lung resected were collected by retrospective chart review. The data were analyzed using multivariable logistic regression to identify independent predictors of AKI.

RESULTS

Acute kidney injury occurred within 48 hr in 57/1,045 (5.5%; 95% confidence interval, 4.2 to 7.0) of patients. On multivariable analysis, our model of best fit included preoperative serum creatinine, male sex, use of angiotensin II receptor blockers, and duration of OLV. The rate of complications, intensive care unit admission, and risk of death were all higher in the group of patients who experienced AKI.

CONCLUSIONS

Acute kidney injury occurs frequently after lung resection surgery and is associated with increased risk of postoperative complications. Increased duration of OLV may be a risk factor for AKI in this population.

Acute Kidney Injury after Cardiac Surgery: Prediction, Prevention, and Management

Acute kidney injury (AKI) is a common complication in cardiac surgery patients, with a reported incidence of 20 to 30%. The development of AKI is associated with worse short- and long-term mortality, and longer hospital length of stay. The pathogenesis of cardiac surgery-associated AKI is poorly understood but likely involves an interplay between preoperative comorbidities and perioperative stressors. AKI is commonly diagnosed by using increases in serum creatinine or decreased urine output and staged using a standardized definition such as the Kidney Disease Improving Global Outcomes classification. Novel biomarkers under investigation may provide earlier detection and better prediction of AKI, enabling mitigating therapies early in the perioperative period. Recent clinical trials of cardiac surgery patients have demonstrated the benefit of goal-directed oxygen delivery, avoidance of hyperthermic perfusion and specific fluid and medication strategies. This review article highlights both advances and limitations regarding the prevention, prediction, and treatment of cardiac surgery-associated AKI.

Renin-Angiotensin-Aldosterone System Blockade after AKI with or without Recovery among US Veterans with Diabetic Kidney Disease

SIGNIFICANCE STATEMENT

Among patients with CKD, optimal use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers after AKI is uncertain. Despite these medications' ability to reduce risk of mortality and other adverse outcomes, there is concern that ACEi/ARB use may delay recovery of kidney function or precipitate recurrent AKI. Prior studies have provided conflicting data regarding the optimal timing of these medications after AKI and have not addressed the role of kidney recovery in determining appropriate timing. This study in US Veterans with diabetes mellitus and proteinuria demonstrated an association between ACEi/ARB use and lower mortality. This association was more pronounced with earlier post-AKI ACEi/ARB use and was not meaningfully affected by initiating ACEis/ARBs before versus after recovery from AKI.

BACKGROUND

Optimal use of angiotensin-converting enzyme inhibitors (ACEis) or angiotensin II receptor blockers (ARBs) after AKI is uncertain.

METHODS

Using data derived from electronic medical records, we sought to estimate the association between ACEi/ARB use after AKI and mortality in US military Veterans with indications for such treatment (diabetes and proteinuria) while accounting for AKI recovery. We used ACEi/ARB treatment after hospitalization with AKI (defined as serum creatinine ≥50% above baseline concentration) as a time-varying exposure in Cox models. The outcome was all-cause mortality. Recovery was defined as return to ≤110% of baseline creatinine. A secondary analysis focused on ACEi/ARB use relative to AKI recovery (before versus after).

RESULTS

Among 54,735 Veterans with AKI, 31,146 deaths occurred over a median follow-up period of 2.3 years. Approximately 57% received an ACEi/ARB <3 months after hospitalization. In multivariate analysis with time-varying recovery, post-AKI ACEi/ARB use was associated with lower risk of mortality (adjusted hazard ratio [aHR], 0.74; 95% confidence interval [CI], 0.72 to 0.77). The association between ACEi/ARB use and mortality varied over time, with lower mortality risk associated with earlier initiation ( P for interaction with time <0.001). In secondary analysis, compared with those with neither recovery nor ACEi/ARB use, risk of mortality was lower in those with recovery without ACEi/ARB use (aHR, 0.90; 95% CI, 0.87 to 0.94), those without recovery with ACEi/ARB use (aHR, 0.69; 95% CI, 0.66 to 0.72), and those with ACEi/ARB use after recovery (aHR, 0.70; 95% CI, 0.67 to 0.73).

CONCLUSIONS

This study demonstrated lower mortality associated with ACEi/ARB use in Veterans with diabetes, proteinuria, and AKI, regardless of recovery. Results favored earlier ACEi/ARB initiation.

Future Directions in Optimizing Anesthesia to Reduce Perioperative Acute Kidney Injury

BACKGROUND

Perioperative acute kidney injury (AKI) is common in surgical patients and is associated with high morbidity and mortality. There are currently few options for AKI prevention and treatment. Due to its complex pathophysiology, there is no efficient medication therapy to stop the onset of the injury or repair the damage already done. Certain anesthetics, however, have been demonstrated to affect the risk of perioperative AKI in some studies. The impact of anesthetics on renal function is particularly important as it is closely related to the prognosis of patients. Some anesthetics can induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. Propofol, sevoflurane, and dexmedetomidine are a few examples of anesthetics that have protective association with AKI in the perioperative period.

SUMMARY

In this study, we reviewed the clinical characteristics, risk factors, and pathogenesis of AKI. Subsequently, the protective effects of various anesthetic agents against perioperative AKI and the latest research are introduced.

KEY MESSAGE

This work demonstrates that a thorough understanding of the reciprocal effects of anesthetic drugs and AKI is crucial for safe perioperative care and prognosis of patients. However, more complete mechanisms and pathophysiological processes still need to be further studied.

Association between Premorbid Renin-Angiotensin-Aldosterone System Blockade and the Risk of Acute Kidney Injury in Critically Ill Patients

Background

Angiotensin-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) are commonly used for hypertension and cardiovascular diseases. However, whether their use increases the risk of acute kidney injury (AKI) and should be discontinued during acute illness remains controversial.

Methods

This retrospective study enrolled 952 dialysis-free patients who were admitted to intensive care units (ICUs) between 2015 and 2017, including 476 premorbid long-term (> 1 month) ACEi/ARB users. Propensity score matching was performed to adjust for age, gender, comorbidities, and disease severity. The primary endpoint was the occurrence of AKI during hospitalization, and the secondary endpoint was mortality or dialysis within 1 year.

Results

Compared with non-users, the ACEi/ARB users were not associated with an increased AKI risk during hospitalization [66.8% vs. 70.4%; hazard ratio (HR): 1.13, 95% confidence interval (CI): 0.97-1.32, p = 0.126]. However, the ACEi/ARB users with sepsis (HR: 1.29, 95% CI: 1.04-1.60, p = 0.021) or hypotension (HR: 1.21, 95% CI: 1.02-1.14, p = 0.034) were found to have an increased AKI risk in subgroup analysis. Nevertheless, compared with the non-users, the ACEi/ARB users were associated with a lower incidence of mortality or dialysis within 1 year (log-rank p = 0.011).

Conclusions

Premorbid ACEi/ARB usage did not increase the incidence of AKI, and was associated with a lower 1-year mortality and dialysis rate in patients admitted to ICUs. Regarding the results of subgroup analysis, renin-angiotensin-aldosterone system blockade may still be safe and beneficial in the absence of sepsis or circulation failure. Further large-scale studies are needed to confirm our findings.

Metformin use is associated with reduced acute kidney injury following coronary artery bypass grafting in patients with type 2 diabetes: An inverse probability of treatment weighting analysis

STUDY OBJECTIVE

Acute kidney injury (AKI) is a common and serious complication after coronary artery bypass grafting (CABG) surgery. Patients with diabetes are commonly associated with renal microvascular complications and have a greater risk of AKI after CABG surgery. This study aimed to explore whether preoperative metformin administration could reduce the incidence of postoperative AKI following CABG in patients with type 2 diabetes.

DESIGN

Patients with diabetes who underwent CABG were retrospectively included in this study. AKI after CABG was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria. The effects of metformin on postoperative AKI following CABG in patients were compared and analyzed.

DATA SOURCE

Patients were enrolled in this study between January 2019 and December 2020 in Beijing Anzhen Hospital.

PATIENTS

A total of 812 patients were enrolled. The patients were divided into the metformin group (203 cases) and the control group (609 cases) according to whether metformin was used preoperatively.

INTERVENTION

Inverse probability of treatment weighting (IPTW) was applied to minimize baseline differences between the two groups. IPT-weighted p values were analyzed to evaluate the postoperative outcomes between the two groups.

MEASUREMENTS AND MAIN RESULTS

The incidence of AKI in the metformin group and the control group was compared. After IPTW adjustment, the incidence of AKI in the metformin group was lower than the control group (IPTW-adjusted p < 0.001). In the subgroup analysis, metformin showed significant protective effects in the estimated glomerular filtration rate (eGFR) < 60 mL/min per 1.73 m2 and eGFR 60-90 mL/min per 1.73 m2 subgroups, which was not observed in the eGFR ≥90 mL/min per 1.73 m2 subgroup. No significant differences in the incidence of renal replacement therapy, reoperation due to bleeding, in-hospital mortality, or red blood cell transfusion volume were observed between the two groups.

CONCLUSIONS

In this study, we provided evidence that preoperative metformin was associated with a significant reduction of postoperative AKI following CABG in patients with diabetes. Metformin showed significant protective effects in patients with mild-to-moderate renal insufficiency.

A randomized clinical trial assessing the effect of automated medication-targeted alerts on acute kidney injury outcomes

Acute kidney injury is common among hospitalized individuals, particularly those exposed to certain medications, and is associated with substantial morbidity and mortality. In a pragmatic, open-label, National Institutes of Health-funded, parallel group randomized controlled trial (clinicaltrials.gov NCT02771977), we investigate whether an automated clinical decision support system affects discontinuation rates of potentially nephrotoxic medications and improves outcomes in patients with AKI. Participants included 5060 hospitalized adults with AKI and an active order for any of three classes of medications of interest: non-steroidal anti-inflammatory drugs, renin-angiotensin-aldosterone system inhibitors, or proton pump inhibitors. Within 24 hours of randomization, a medication of interest was discontinued in 61.1% of the alert group versus 55.9% of the usual care group (relative risk 1.08, 1.04 - 1.14, p = 0.0003). The primary outcome - a composite of progression of acute kidney injury, dialysis, or death within 14 days - occurred in 585 (23.1%) of individuals in the alert group and 639 (25.3%) of patients in the usual care group (RR 0.92, 0.83 - 1.01, p = 0.09). Trial Registration Clinicaltrials.gov NCT02771977.

Sirtuin 6 is a key contributor to gender differences in acute kidney injury

Acute kidney injury (AKI) is rapidly increasing nowadays and at a high risk to progress into chronic kidney disease (CKD). Of note, men are more susceptive to AKI, suggesting gender differences in AKI patients. However, the underlying mechanisms remain largely unclear. To test it, we adopted two experimental models of AKI, including ischemia/reperfusion injury and rhabdomyolysis, which were constructed in age-matched male and female mice. We found severe damages of tubular apoptosis, mitochondrial dysfunction, and loss of renal function showing in male mice, while female mice only had very mild injury. We further tested the expression of Sirtuins, and found that female mice could preserve more Sirtuin members' expression in case of kidney damage. Among Sirtuin family, Sirtuin 6 was maximally preserved in injured kidney in female mice, suggesting its important role involved in the gender differences of AKI pathogenesis. We then found that knockdown of androgen receptor (AR) attenuated tubular damage, mitochondrial dysfunction and retarded the loss of renal function. Overexpression of Sirtuin 6 also showed similar results. Furthermore, in cultured tubular cells, dihydrotestosterone (DHT) decreased Sirtuin 6 expression and exacerbated cell apoptosis. Ectopic expression of Sirtuin 6 sufficiently inhibited DHT-induced cell apoptosis. Mechanically, we found AR inhibited Sirtuin 6, leading to the repression of binding of Sirtuin 6 with PGC-1α. This resulted in acetylation of PGC-1α and inhibition of its activity, further triggered the loss of mitochondrial homeostasis. Our results provided new insights to the underlying mechanisms of gender differences in AKI, suggesting Sirtuin 6 maybe a new therapeutic target for preventing AKI in male patients.

Perioperative Renin-Angiotensin System Inhibitors Improve Major Outcomes of Heart Failure Patients Undergoing Cardiac Surgery: A Propensity-Adjusted Cohort Study

OBJECTIVE

The aim of this study was to study the association of perioperative administration of renin angiotensin system inhibitors (RASi) and clinical outcomes of patients with heart failure (HF) undergoing cardiac surgery.

SUMMARY BACKGROUND DATA

It is controversial whether the perioperative RASi should be administered in HF patients undergoing cardiac surgery.

METHODS

A total of 2338 patients with HF and undergoing CABG and/or valve surgeries at multiple hospitals from 2001 to 2015 were identified from STS database. After adjustment using propensity score and instrumental variable, logistic regression was conducted to analyze the influence of preoperative continuation of RASi (PreRASi) on short-term in-hospital outcomes. Independent risk factors of 30-day mortality, major adverse cardiovascular events (MACE), and renal failure were analyzed by use of stepwise logistic regression. The effects of pre- and postoperative use of RASi (PostRASi) on long-term mortality were analyzed using survival analyses. Stepwise Cox regression was conducted to analyze the independent risk factors of 6-year mortality. The relationships of HF status and surgery type with perioperative RASi, as well as PreRASi-PostRASi, were also evaluated by subgroup analyses.

RESULTS

PreRASi was associated with lower incidences of 30-day mortality [ P < 0.0001, odds ratio (OR): 0.556, 95% confidence interval (CI) 0.405-0.763], stroke ( P =0.035, OR: 0.585, 95% CI: 0.355-0.962), renal failure ( P =0.007, OR: 0.663, 95% CI: 0.493-0.894). Both PreRASi ( P =0.0137) and PostRASi ( P =0.007) reduced 6-year mortality compared with the No-RASi groups.

CONCLUSIONS

Pre- and postoperative use of RASi was associated with better outcomes for the patients who have HF and undergo CABG and/or valve surgeries. Preoperative continuation and postoperative restoration are warranted in these patients.

Association Between Proton Pump Inhibitor Exposure and Acute Kidney Injury After Cardiac Surgery

OBJECTIVE

To evaluate the association of preoperative proton pump inhibitor (PPI) exposure with incident acute kidney injury (AKI) after cardiac surgery.

PATIENTS AND METHODS

The Severance cardiac surgery cohort included 9860 cardiac surgery patients aged 18 years or older. The National Health Insurance Service-senior cohort included 2933 patients aged 60 years or older who underwent cardiac surgery. Preoperative PPI exposure was defined as a PPI prescription within 3 weeks prior to cardiac surgery. Primary outcomes were postoperative AKI and AKI requiring dialysis (AKI-dialysis).

RESULTS

In the Severance cardiac surgery cohort after propensity score matching for PPI exposure, incident AKI (44.0% [472 of 1073] vs 40.5% [1304 of 3219]) and AKI-dialysis (5.8% [62 of 1073] vs 3.7% [119 of 3219]) were more common in patients exposed to PPI than in those who were not. Hospital and intensive care unit stay durations were longer among PPI-exposed than PPI-nonexposed patients. Multivariable conditional logistic analyses revealed that PPI exposure was significantly associated with incident AKI (adjusted odds ratio [AOR], 1.21; 95% CI, 1.03 to 1.42; P=.02) and AKI-dialysis (AOR, 1.74; 95% CI, 1.15 to 2.63; P=.009). The National Health Insurance Service-Senior cohort had similar results, revealing a significant association between PPI exposure and incident AKI-dialysis (AOR, 1.87; 95% CI, 1.25 to 2.81; P=.003). Discontinuation of PPI prior to operation was associated with a lower odds of AKI development in both cohorts.

CONCLUSION

Preoperative PPI exposure may be a modifiable risk factor for AKI among patients undergoing cardiac surgery.

Long-Term Effects of Severe Burns on the Kidneys: Research Advances and Potential Therapeutic Approaches

Burns are a seriously underestimated form of trauma that not only damage the skin system but also cause various complications, such as acute kidney injury (AKI). Recent clinical studies have shown that the proportion of chronic kidney diseases (CKD) in burn patients after discharge is significantly higher than that in the general population, but the mechanism behind this is controversial. The traditional view is that CKD is associated with hypoperfusion, AKI, sepsis, and drugs administered in the early stages of burns. However, recent studies have shown that burns can cause long-term immune dysfunction, which is a high-risk factor for CKD. This suggests that burns affect the kidneys more than previously recognized. In other words, severe burns are not only an acute injury but also a chronic disease. Neglecting to study long-term kidney function in burn patients also results in a lack of preventive and therapeutic methods being developed. Furthermore, stem cells and their exosomes have shown excellent comprehensive therapeutic properties in the prevention and treatment of CKD, making them increasingly the focus of research attention. Their engineering strategy further improved the therapeutic performance. This review will focus on the research advances in burns on the development of CKD, illustrating the possible mechanism of burn-induced CKD and introducing potential biological treatment options and their engineering strategies.

Perioperative Management of the Patient at High-Risk for Cardiac Surgery-Associated Acute Kidney Injury

Acute kidney injury (AKI) is one of the most common major complications of cardiac surgery, and is associated with increased morbidity and mortality. Cardiac surgery-associated AKI has a complex, multifactorial etiology, including numerous factors such as primary cardiac dysfunction, hemodynamic derangements of cardiac surgery and cardiopulmonary bypass, and the possibility of a large volume of blood transfusion. There are no truly effective pharmacologic therapies for the management of AKI, and, therefore, anesthesiologists, intensivists, and cardiac surgeons must remain vigilant and attempt to minimize the risk of developing renal dysfunction. This narrative review describes the current state of the scientific literature concerning the specific aspects of cardiac surgery-associated AKI, and presents it in a chronological fashion to aid the perioperative clinician in their approach to this high-risk patient group. The evidence was considered for risk prediction models, preoperative optimization, and the intraoperative and postoperative management of cardiac surgery patients to improve renal outcomes.

Angiotensin II Receptor Blocker Associated With Less Outcome Risk in Patients With Acute Kidney Disease

Objective: The aim of this study was to explore the respective use of angiotensin-converting-enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) on the outcomes of patients who could be weaned from dialysis-requiring acute kidney injury (AKI-D). Methods: This case-control study enrolled 41,731 patients who were weaned from AKI-D for at least 7 days from Taiwan's National Health Insurance Administration. We further grouped AKI-D patients according to ACEi and ARB use to evaluate subsequent risks of all-cause mortality and re-dialysis. The outcomes included the all-cause mortality and new-onset of end-stage kidney disease (ESKD; re-dialysis) following withdraw from AKI-D. Results: A total of 17,141 (41.1%) patients surviving AKI-D could be weaned from dialysis for at least 7 days. The overall events of mortality were 366 (48.9%) in ACEi users, 659 (52.1%) in ARB users, and 6,261 (41.3%) in ACEi/ARB nonusers, during a mean follow-up period of 1.01 years after weaning from AKI-D. In regard to all-cause of mortality, pre-dialysis ARB users had lower incidence than ACEi users [hazard ratio (HR 0.82), p = 0.017]. Compared with ACEi/ARB nonusers, continuing ARB users had a significantly low risk of long-term all-cause mortality (adjusted hazard ratio 0.51, p = 0.013) after propensity score matching. However, new users of ACEi at the acute kidney disease (AKD) period had a higher risk of re-dialysis after weaning than ACEi/ARB nonusers (aHR 1.82, p < 0.001), whereas neither ACEi nor ARB users confronted significantly increased risks of hyperkalemia after weaning. Conclusions: Compared with patients without ACEi/ARB, those continuing to use ARB before the event and after weaning had low all-cause mortality, while new users of ACEi at AKD had increased risk of re-dialysis. AKI-D patients continuing to use ACEi or ARB did not have higher risk of hyperkalemia. Future prospective randomized trials are expected to confirm these findings.

Intraoperative venous congestion rather than hypotension is associated with acute adverse kidney events after cardiac surgery: a retrospective cohort study

BACKGROUND

The pathophysiological mechanisms by which venous congestion and hypotension lead to acute adverse kidney events after cardiac surgery with cardiopulmonary bypass have not been elucidated. We tested the hypothesis that intraoperative hypotension and venous congestion are associated with acute kidney injury and acute kidney disease.

METHODS

Primary exposures were venous congestion and intraoperative hypotension defined by central venous pressure ≥12, 16, or 20 mm Hg or mean arterial pressure ≤55, 65, or 75 mm Hg. The primary outcomes were acute kidney injury and acute kidney disease. Multivariable logistic regression and Cox proportional hazard models were used, adjusted for relevant confounding factors and multiple comparisons.

RESULTS

Of 5127 eligible subjects, 1070 (20.9%) and 327 (7.2%) developed acute kidney injury and acute kidney disease, respectively. The occurrence of acute kidney injury was statistically associated with both venous congestion and intraoperative hypotension. The cumulative incidence rate for new onset acute kidney disease was 1.34 (95% confidence interval [CI], 1.21-1.60) per 100 person-days. Acute kidney disease was significantly associated with each 10 min epoch of central venous pressure ≥12 mm Hg (hazard ratio [HR]=1.03; 99% CI, 1.01-1.06; P<0.001), ≥16 mm Hg (HR=1.04; 99% CI, 1.01-1.07; P<0.001), and ≥20 mm Hg (HR=1.07; 99% CI, 1.02-1.13; P<0.001). Venous congestion was associated with an 8-17% increased risk for de novo renal replacement therapy. In contrast, intraoperative hypotension was not associated with development of acute kidney disease.

CONCLUSION

Although both venous congestion and intraoperative hypotension are associated with acute kidney injury, only venous congestion correlates with acute kidney disease among patients undergoing cardiac surgery requiring cardiopulmonary bypass. The reported associations are suggestive of a pathophysiological role of venous congestion in acute kidney disease.

Renin-angiotensin system inhibitors combined with cisplatin exacerbate cisplatin-induced nephrotoxicity in mice

INTRODUCTION

We previously reported that the concomitant use of enalapril and telmisartan exacerbates the risk of cisplatin (CDDP)-induced acute renal dysfunction compared to other antihypertensive drugs in mice. Thus, in the current study, we investigated the risk of developing chronic kidney disease following repeated concomitant use of CDDP and antihypertensive drugs.

MATERIALS AND METHODS

Male BALB/c mice were divided into 12 groups: (1) Control group (untreated), (2) CDDP group (7 mg/kg, CDDP), (3) AML group (5 mg/kg, amlodipine), (4) ENA group (2.5 mg/kg, enalapril), (5) TEL group (10 mg/kg, telmisartan), (6) LOS group (10 mg/kg, losartan), (7) CDDP+AML group (5 mg/mL, AML), (8) CDDP+ENA group (2.5 mg/kg, ENA), (9) CDDP+LowENA group (1.25 mg/kg, ENA), (10) CDDP+TEL group (10 mg/kg, TEL), (11) CDDP+LowTEL group (5 mg/kg, TEL), and (12) CDDP+LOS group (10 mg/kg, LOS). CDDP was administered intraperitoneally four times every 7 days, and each antihypertensive drug was administered orally from day 3 before CDDP administration until day 24 (six times a week). The degree of renal damage was assessed. The nephrotoxicity of each individual was evaluated by measuring serum creatinine and blood urea nitrogen levels. The degrees of renal fibrosis and epithelial-mesenchymal transition were also examined in kidney tissue sections.

RESULTS AND DISCUSSION

The results suggest that combinatorial treatment of CDDP and renin-angiotensin system inhibitors, particularly ENA and TEL, may exacerbate CDDP-induced nephrotoxicity. This study clearly demonstrates the need for large-scale clinical studies to construct treatment regimens that do not interfere with the therapeutic intensity of CDDP.

Stopping Versus Continuing Renin-Angiotensin System Inhibitors After Acute Kidney Injury and Adverse Clinical Outcomes; An Observational Study From Routine Care Data

Background

The risk–benefit ratio of continuing with renin–angiotensin system inhibitors (RASi) after an episode of acute kidney injury (AKI) is unclear. While stopping RASi may prevent recurrent AKI or hyperkalaemia, it may deprive patients of the cardiovascular benefits of using RASi.

Methods

We analysed outcomes of long-term RASi users experiencing AKI (stage 2 or 3, or clinically coded) during hospitalization in Stockholm and Sweden during 2007–18. We compared stopping RASi within 3 months after discharge with continuing RASi. The primary study outcome was the composite of all-cause mortality, myocardial infarction (MI) and stroke. Recurrent AKI was our secondary outcome and we considered hyperkalaemia as a positive control outcome. Propensity score overlap weighted Cox models were used to estimate hazard ratios (HRs), balancing 75 confounders. Weighted absolute risk differences (ARDs) were also determined.

Results

We included 10 165 individuals, of whom 4429 stopped and 5736 continued RASi, with a median follow-up of 2.3 years. The median age was 78 years; 45% were women and median kidney function before the index episode of AKI was 55 mL/min/1.73 m². After weighting, those who stopped had an increased risk [HR, 95% confidence interval (CI)] of the composite of death, MI and stroke [1.13, 1.07–1.19; ARD 3.7, 95% CI 2.6–4.8] compared with those who continued, a similar risk of recurrent AKI (0.94, 0.84–1.05) and a decreased risk of hyperkalaemia (0.79, 0.71–0.88).

Discussion

Stopping RASi use among survivors of moderate-to-severe AKI was associated with a similar risk of recurrent AKI, but higher risk of the composite of death, MI and stroke.

Analysis of Risk Factors for Perioperative Acute Kidney Injury and Management Strategies

Acute kidney injury (AKI) is a serious clinical syndrome, and one of the common comorbidities in the perioperative period. AKI can lead to complications in surgical patients and is receiving increasing attention in clinical workup. In recent years, the analysis of perioperative risk factors has become more in-depth and detailed. In this review, the definition, diagnosis, and pathophysiological characteristics of perioperative AKI are reviewed, and the main risk factors for perioperative AKI are analyzed, including advanced age, gender, certain underlying diseases, impaired clinical status such as preoperative creatinine levels, and drugs that may impair renal function such as non-steroidal anti-inflammatory drugs (NASIDs), ACEI/ARB, and some antibiotics. Injectable contrast agents, some anesthetic drugs, specific surgical interventions, anemia, blood transfusions, hyperglycemia, and malnutrition are also highlighted. We also propose potential preventive and curative measures, including the inclusion of renal risk confirmation in the preoperative assessment, minimization of intraoperative renal toxin exposure, intraoperative management and hemodynamic optimization, remote ischemic preadaptation, glycemic control, and nutritional support. Among the management measures, we emphasize the need for careful perioperative clinical examination, timely detection and management of AKI complications, administration of dexmedetomidine for renal protection, and renal replacement therapy. We aim that this review can further increase clinicians' attention to perioperative AKI, early assessment and intervention to try to reduce the risk of AKI.

Impact of Renin-Angiotensin System Blockers on Mortality in Veterans Undergoing Cardiac Surgery

Background

Renin‐angiotensin system blockers (RASBs) have well‐validated benefit in patients with hypertension, coronary artery disease, and left ventricular systolic dysfunction. Their use in the perioperative period, however, has been controversial, including in patients undergoing cardiac surgery, who often have a strong indication for their use. In the current study, we explore the impact of RASB use with 30‐day and 1‐year mortality after cardiac surgery.

Methods and Results

The Veterans Affairs Surgical Quality Improvement Program and Corporate Data Warehouse were data sources for this retrospective cohort study. A total of 37 197 veterans undergoing elective coronary artery bypass grafting and or valve repair or replacement over a 10‐year period met inclusion criteria and were stratified into 4 groups by preoperative exposure (preoperative exposure versus no preoperative exposure) and postoperative continuing exposure (current exposure versus no current exposure) to RASBs. After adjusting for all baseline covariates, the preoperative exposure/current exposure group had lower 30‐day and 1‐year mortality than the preoperative exposure/no current exposure (30‐day hazard ratio [HR], 0.25; 95% CI, 0.19–0.33 [P<0.001] and 1‐year HR, 0.40; 95% CI, 0.33–0.48 [P<0.001] or no preoperative exposure/no current exposure (30‐day HR, 0.44; 95% CI, 0.32–0.60 [P<0.001] and 1‐year HR, 0.72; 95% CI, 0.62–0.84 [P<0.001] groups. The no preoperative exposure/current exposure group had significantly lower 30‐day (HR, 0.31; 95% CI, 0.14–0.71 [P=0.006]) and 1‐year (HR, 0.64; 95% CI, 0.53–0.77 [P<0.001]) mortality than the no preoperative exposure/no current exposure group.

Conclusions

Continuation of preoperative RASBs and initiation before discharge is associated with decreased mortality in veterans undergoing cardiac surgery. Given these findings, continuation of preoperative RASBs or initiation in the early postoperative period should be considered in patients undergoing cardiac surgery.

Angiotensin II Receptor Blockers but Not Angiotensin-Converting Enzyme Inhibitors Are Associated With a Reduced Risk of Acute Kidney Injury After Major Surgery

Objective: We investigated the respective effects of preoperative angiotensin-converting-enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) on the incidence of postoperative acute kidney injury (AKI) and mortality.

Methods: In this nested case-control study, we enrolled 20,276 patients who received major surgery. We collected their baseline demographic data, comorbidities and prescribed medication, the outcomes of postoperative AKI and mortality. AKI was defined by the criteria suggested by KDIGO (Kidney disease: Improving Global Outcome). Logistic regression was used to assess the impact of exposure to ACEIs or ARBs.

Results: Compared with patients without ACEI/ARB, patient who received ARBs had a significantly lower risk for postoperative AKI (adjusted odds ratio (OR) 0.82, p = 0.007). However, ACEI users had a higher risk for postoperative AKI than ARB users (OR 1.30, p = 0.027), whereas the risk for postoperative AKI was not significantly different between the ACEI users and patients without ACEI/ARB (OR 1.07, p = 0.49). Compared with patients without ACEI/ARB, both ACEI and ARB users were associated with a reduced risk of long-term all-cause mortality following surgery (OR 0.47, p = 0.002 and 0.60, p < 0.001 in ACEI and ARB users, respectively), without increasing the risk of hyperkalemia during the index hospitalization (p = 0.20). The risk of long-term all-cause mortality following surgery in ACEIs and ARBs users did not differ significantly (OR 0.74, p = 0.27). Furthermore, the higher the defined daily dose of ARB, the better the protection against AKI provided.

Conclusion: Our study revealed that preoperative use of ARBs was associated with reduced postoperative AKI, which is better in high quantity, whereas preoperative use of ACEIs or ARBs were both associated with reduced mortality and did not increase the risk of hyperkalemia.

Angiotensin-Converting Enzyme Inhibitor/Receptor Blocker, Diuretic, or Nonsteroidal Anti-inflammatory Drug Use After Major Surgery and Acute Kidney Injury: A Case-Control Study

BACKGROUND

Acute kidney injury (AKI) is common after surgery and associated with increased mortality, costs, and lengths of hospitalization. We examined associations between angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB), diuretic, or nonsteroidal anti-inflammatory drug (NSAID) use after major surgery and AKI.

MATERIALS AND METHODS

We conducted a nested case-control study of patients who underwent major cardiac, thoracic, general, or vascular surgery in Calgary, Alberta, Canada. Cases with AKI were matched on age, gender, and surgery type with up to five controls without AKI within 30-d after surgery. Adjusted odds ratios (ORs) for AKI were determined based on postoperative administration of ACEIs/ARBs, diuretics, or NSAIDs.

RESULTS

Among 33,648 patients in the cohort, 2911 cases with AKI were matched to 9309 controls without AKI. Postoperative diuretic [OR = 1.96; 95% confidence interval (CI) = 1.68-2.29], but not ACEI/ARB (OR = 0.83; 95% CI = 0.72-0.95) or NSAID (OR = 1.12; 95% CI = 0.96-1.31), use was independently associated with higher odds of AKI (including stages 1 and 2/3 AKI) after all types of major surgery. There were increased adjusted odds of AKI 1 to 5 d after first exposure to diuretics and 1 d after first exposure to NSAIDs (but not after later exposures). Relationships between ACEI/ARB use and AKI varied by surgery type (p-interaction = 0.004), with lower odds of AKI observed among ACEI/ARB use after cardiac surgery (OR = 0.70; 95% CI = 0.57-0.81), but no difference after other major surgeries.

CONCLUSIONS

Postoperative administration of diuretics and NSAIDs was associated with increased odds of AKI after major surgery. These findings characterize potentially modifiable medication exposures associated with AKI after surgery.

Angiotensin II type 1a receptor loss ameliorates chronic tubulointerstitial damage after renal ischemia reperfusion

We investigate whether suppressing the activation of the angiotensin II type 1a receptor (AT1a) can ameliorate severe chronic tubulointerstitial damage (TID) after renal ischemia reperfusion (IR) using AT1a knockout homozygous (AT1a^−/−) male mice. To induce severe chronic TID after renal IR, unilateral renal ischemia was performed via clamping of the right renal pedicle in both AT1a^−/− and wild-type (AT1a^+/+) mice for 45 min. While marked renal atrophy and severe TID at 70 days postischemia was induced in the AT1a^+/+ mice, such a development was not provoked in the AT1a^−/− mice. Although the AT1a^+/+ mice were administered hydralazine to maintain the same systolic blood pressure (SBP) levels as the AT1a^−/− mice with lower SBP levels, hydralazine did not reproduce the renoprotective effects observed in the AT1a^−/− mice. Acute tubular injury at 3 days postischemia was similar between the AT1a^−/− mice and the AT1a^+/+ mice. From our investigations using IR kidneys at 3, 14, and 28 days postischemia, the multiple molecular mechanisms may be related to prevention of severe chronic TID postischemia in the AT1a^−/− mice. In conclusion, inactivation of the AT1 receptor may be useful in preventing the transition of acute kidney injury to chronic kidney disease.

Prospective Cohort Study of Renin-Angiotensin System Blocker Usage after Hospitalized Acute Kidney Injury

BACKGROUND AND OBJECTIVES

The risk-benefit ratio of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy after AKI may be altered due to concerns regarding recurrent AKI. We evaluated, in a prospective cohort, the association between use (versus nonuse) of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and the subsequent risk of AKI and other adverse outcomes after hospitalizations with and without AKI.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied 1538 patients recently discharged from the hospital who enrolled in the multicenter, prospective ASSESS-AKI study, with approximately half of patients experiencing AKI during the index hospitalization. All participants were seen at a baseline visit 3 months after their index hospitalization and were categorized at that time on whether they were using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers or not. We used multivariable Cox regression, adjusting for demographics, comorbidities, eGFR, urine protein-creatinine ratio, and use of other medications, to examine the association between angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use and subsequent risks of AKI, death, kidney disease progression, and adjudicated heart-failure events.

RESULTS

The use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers was 50% (386/769) among those with AKI during the index hospitalization and 47% (362/769) among those without. Among those with AKI during the index hospitalization, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use was not associated with a higher risk of recurrent hospitalized AKI (adjusted hazard ratio, 0.88; 95% confidence interval, 0.69 to 1.13). Associations between angiotensin-converting enzyme inhibitor/angiotensin receptor blocker use and death, kidney disease progression, and adjudicated heart-failure events appeared similar in study participants who did and did not experience AKI during the index hospitalization (all interaction P values >0.05).

CONCLUSIONS

The risk-benefit ratio of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker therapy after hospital discharge appears to be similar regardless of whether AKI occurred during the hospitalization.

Retrospective Evaluation of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers on Postoperative Estimated Glomerular Filtration Rates Following Robotic-Assisted Partial Nephrectomy

Objective: To evaluate the association between the use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) preoperatively with changes in estimated glomerular filtration rate (eGFR) after robotic-assisted partial nephrectomy (RAPN). Methods: Patients undergoing RAPN at our institution from February 2008 through April 2019 were evaluated. ACEIs/ARBs were held on the morning of the surgery and resumed on postoperative day number one in all patients. Associations of ACEIs/ARBs use with postoperative eGFR were explored by using a linear mixed-effects regression model with random patient-specific intercepts. We included eGFR measurements at the following time points: preoperatively, postoperative day 1 (POD1), 1 month postoperative, 6 months postoperative, and 12 months postoperative. p-Values <0.05 were considered statistically significant. Results: One hundred and seventy-one (44.0%) of 389 patients were on ACEIs/ARBs therapy preoperatively. The ACEIs/ARBs patients were older and had higher rates of comorbidities, including diabetes mellitus. The ACEIs/ARBs patients tended to have lower preoperative eGFR (mean ± standard deviation, 70.4 ± 17.5 vs 78.0 ± 19.2 mL/minute/1.73 m²; p < 0.001). However, this was not significant after adjustment for potentially confounding variables (mean difference, -1.7 mL/minute/1.73 m²; 95% confidence interval, -6.4 to 3.1 mL/minute/1.73 m²; p = 0.48). There was no evidence of an association of ACEIs/ARBs use with postoperative renal function after adjustment for potentially confounding variables (adjusted mean difference in change in eGFR from baseline was -1.1, -1.2, -0.3, and -1.2 mL/minute/1.73 m² at POD1, 1, 6, and 12 months, respectively; all p ≥ 0.51). Conclusion: Continuation of ACEIs and ARBs throughout the perioperative period is not associated with change in post-RAPN eGFR.

Determining the risk of acute kidney injury in patients who underwent total joint replacement: A retrospective study

OBJECTIVES

Total joint replacement (TJR) is a commonly performed procedure worldwide, and postoperative acute kidney injury (AKI) is one of the complications that determine the overall prognosis in various surgical settings. We aimed to identify the risk of AKI after TJR (primary and revision) and determine the factors associated with postoperative AKI.

METHODS

We performed a retrospective study of 1068 patients (>18 years) who underwent TJR between 2014 and 2019 at a tertiary medical center. Patients' demographic, clinical, and laboratory data were reviewed.

RESULTS

A total of 1068 patients were included in this study [mean age, 60.5 ± 13 years; 260 men (24.3%); 808 women (75.7%)]. A total of 962 patients (90.1%) underwent primary joint replacement (PJR) and 106 underwent joint revision (9.9%). Sixty-six patients (6.2%) had postoperative AKI. Primary total hip replacement patients had a lower risk of AKI than patients with other types of TJR (3.0%; p = 0.024). The factors associated with AKI (adjusting for known confounders) included male gender [adjusted odds ratio (AOR): 1.751; 95% confidence interval (CI): 1.01-3.03; p = 0.046], diabetes mellitus (DM) [AOR: 2.806; 95% CI: 1.687-5.023; p ≤ 0.001], hypertension (HTN) [AOR: 1.751; 95% CI: 1.159-3.442; p = 0.013], and the use of vancomycin as a prophylactic antibiotic [AOR: 1.691; 95% CI: 1.1-2.913; p = 0.050]. Chronic kidney disease (CKD) [AOR: 1.00; 95% CI: 0.432-2.27; p = 0.981] was not found to be a significant risk factor.

CONCLUSION

In this study, the risk of preoperative AKI in patients who underwent TJR was 6.2%. Male gender, preoperative comorbidities such as DM and HTN, and preoperative use of vancomycin were associated with increased risk of postoperative AKI.

Predictors of Acute Kidney Injury Following Surgical Valve Replacement

BACKGROUND

 Acute kidney injury is a serious complication after surgical valve replacement and holds increased mortality rates.

OBJECTIVES

 To study predictors of acute kidney injury after surgical valve replacement.

MATERIALS AND METHODS

 Patients who underwent valve surgery procedures at our center were included. Procedures included aortic valve replacement (AVR), mitral valve replacement (MVR), AVR with coronary artery bypass grafting (CABG), MVR with CABG, or AVR and MVR with/without CABG.

RESULTS

 A total of 346 patients were included. The mean age was 51.56 (16.1). Males (n = 178) comprised 51%.At the univariate level analysis, predictors of acute kidney injury were found including age, ejection fraction, hypertension, history of CAD, emergency surgery, recent myocardial infarction, diabetes, atrial fibrillation, history of heart failure, mitral regurgitation (MR), pump time >120 minutes, aortic cross clamp >90 minutes, perioperative blood transfusion, re-exploration for bleeding, use of mechanical and biologic valve in aortic position, use of biologic valve in mitral position, prolonged inotropic support, postoperative stroke, and use of angiotensin converting enzyme inhibitors (ACEi) < a month, (all p < 0.05).By Logistic regression analysis, Age (p < 0.0001, odds ratio[AOR] = 1.076), hypertension (p = 0.039, AOR = 1.829), heart failure (p = 0.019, AOR = 2.448), MR (p = 0.0001, AOR = 3.110), use of ACEi <month (p = 0.043, AOR= 2.181), pump time >120 minutes (p = 0.022, AOR = 1.797), perioperative blood transfusion (p = 0.008, AOR = 2.532), and prolonged inotropic support (p = 0.012, AOR = 2.591) were significant and independent predictors of AKI.

CONCLUSION

 Independent predictors of acute kidney injury following valve surgeries include age, hypertension, heart failure, MR, use of ACEi <month, perioperative blood transfusion, and prolonged pump time or inotropic support.

Independent risk factors and the long-term outcomes for postoperative continuous renal replacement treatment in patients who underwent emergency surgery for type a acute aortic dissection

Objective

The study objective was to investigate the incidence and risk factors of continuous renal replacement therapy (CRRT) in patients undergoing emergency surgery for type A acute aortic dissection (TA-AAD) and evaluate the perioperative and long-term outcomes.

Methods

From January 2014 to December 2018, 712 consecutive patients were enrolled in the study. These patients were divided into two groups according to whether or not needed postoperative CRRT: the CRRT group vs the control group. Univariate analysis and binary logistic regression analysis were used to analyze the risk factors of CRRT. To avoid the selection bias and confounders, baseline characteristics were matched for propensity scores. Kaplan-Meier curves were generated to provide survival estimates at postoperative points in time.

Results

Before propensity score matching, univariate analysis showed that there were significant differences in age, preoperative hypertension, pericardial effusion, preoperative serum creatinine (sCr), intraoperative need for combined coronary artery bypass grafting (CABG) or mitral valve or tricuspid valve surgery, cardiopulmonary bypass (CPB) time, extracorporeal circulation assistant time, aortic cross-clamp time, drainage volume 24 h after surgery and ventilator time between two groups. All were higher in the CRRT group (P < 0.05). These risk factors were included in binary logistic regression. It showed that preoperative sCr and CPB time were independent risk factors for CRRT patients undergoing surgery for TA-AAD. And there were significant differences regarding 30-day mortality (P < 0.001) and long-term overall cumulative survival (P < 0.001) with up to a 6-year follow-up. After propensity scoring, 29 pairs (58 patients) were successfully matched. Among these patients, the analysis showed that CPB time was still significantly longer in the CRRT group (P = 0.004), and the 30-day mortality rate was also higher in this group (44.8% vs 10.3%; P = 0.003).

Conclusion

CRRT after TA-AAD is common and worsened short- and long- term mortality. The preoperative sCr and CPB time are independent risk factors for postoperative CRRT patients. Shorten the CPB time as much as possible is recommended to reduce the risk of CRRT after the operation.

Endocrine Effects of Simulated Complete and Partial Aortic Occlusion in a Swine Model of Hemorrhagic Shock

INTRODUCTION

Low distal aortic flow via partial aortic occlusion (AO) may mitigate ischemia induced by resuscitative endovascular balloon occlusion of the aorta (REBOA). We compared endocrine effects of a novel simulated partial AO strategy, endovascular variable aortic control (EVAC), with simulated REBOA in a swine model.

MATERIALS AND METHODS

Aortic flow in 20 swine was routed from the supraceliac aorta through an automated extracorporeal circuit. Following liver injury-induced hemorrhagic shock, animals were randomized to control (unregulated distal flow), simulated REBOA (no flow, complete AO), or simulated EVAC (distal flow of 100-300 mL/min after 20 minutes of complete AO). After 90 minutes, damage control surgery, resuscitation, and full flow restoration ensued. Critical care was continued for 4.5 hours or until death.

RESULTS

Serum angiotensin II concentration was higher in the simulated EVAC (4,769 ± 624 pg/mL) than the simulated REBOA group (2649 ± 429) (p = 0.01) at 180 minutes. There was no detectable difference in serum renin [simulated REBOA: 231.3 (227.9-261.4) pg/mL; simulated EVAC: 294.1 (231.2-390.7) pg/mL; p = 0.27], aldosterone [simulated EVAC: 629 (454-1098), simulated REBOA: 777 (575-1079) pg/mL, p = 0.53], or cortisol (simulated EVAC: 141 ± 12, simulated REBOA: 127 ± 9 ng/mL, p = 0.34) concentrations between groups.

CONCLUSIONS

Simulated EVAC was associated with higher serum angiotensin II, which may have contributed to previously reported cardiovascular benefits. Future studies should evaluate the renal effects of EVAC and the concomitant therapeutic use of angiotensin II.

Risk factors for acute kidney injury in patients with acute myocardial infarction

BACKGROUND

Acute kidney injury (AKI) is a serious and fatal complication of acute myocardial infarction (AMI). It has high short- and long-term mortality rates and a poor prognosis but is potentially preventable. However, the current incidence, risk factors, and outcomes of AKI in the Chinese population are not well understood and would serve the first step to identify high-risk patients who could receive preventative care.

METHODS

The medical data of 1124 hospitalized patients diagnosed with AMI from October 2013 to September 2015 were reviewed. AKI was defined according to the 2012 Kidney Disease Improving Global Outcomes criteria. All the patients were divided into either the AKI group or the non-AKI group. A univariate comparison analysis was performed to identify possible risk factors associated with AKI. A multiple logistic regression analysis was used to identify the independent risk factors for AKI in patients with AMI.

RESULTS

Overall, the incidence of AKI was 26.0%. The mortality rate of the AKI group was 20.5%, and the mortality rate of the non-AKI group was 0.6% (P < 0.001). Logistic regression analysis showed that the independent risk factors for AKI in patients with AMI included: age (>60 years old) (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.05, P = 0.000), hypertension (OR 2.51, 95% CI 1.62-3.87, P = 0.000), chronic kidney disease (OR 3.52, 95% CI 2.01-6.16, P = 0.000), Killip class ≥3 (OR 5.22, 95% CI 3.07-8.87, P = 0.000), extensive anterior myocardial infarction (OR 3.02, 95% CI 1.85-4.93, P = 0.000), use of furosemide (OR 1.02, 95% CI 1.02-1.03, P = 0.000), non-use of angiotensin-converting enzyme inhibitors/angiotensin receptor blocker (OR 1.58, 95% CI 1.04-2.40, P = 0.032). These factors provided an accurate tool to identify patients at high risk of developing AKI.

CONCLUSIONS

Approximately 26.0% of patients undergoing AMI developed AKI, and the development of AKI was strongly correlated with in-hospital mortality. The risk factors for AKI in patients with AMI were determined to help identify high-risk patients and make appropriate clinical decisions.

Renin-Angiotensin System Blockade after Acute Kidney Injury (AKI) and Risk of Recurrent AKI

BACKGROUND AND OBJECTIVES

How to best medically manage patients who survived hospitalized AKI is unclear. Use of renin-angiotensin system blockers in this setting may increase risk of recurrent AKI.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a cohort study of 10,242 members of an integrated health care delivery system in Northern California who experienced AKI and survived a hospitalization between January 1, 2006 and December 31, 2013. All study participants did not have prior heart failure or use of angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) up to 5 years prior. New receipt and time-updated exposure of ACE-Is/ARBs was identified on the basis of dispensed prescriptions found in outpatient health plan pharmacy databases. The main outcome of interest was subsequent episode of hospitalized AKI after discharge from an initial index hospitalization complicated by AKI. Recurrent AKI episode was defined using acute changes in serum creatinine concentrations. Marginal structural models were used to adjust for baseline and potential time-dependent confounders.

RESULTS

Forty-seven percent of the study population had a documented eGFR<60 ml/min per 1.73 m² or documented proteinuria before hospitalization. With a median of 3 (interquartile range, 1-5) years of follow-up, 1853 (18%) patients initiated use of ACE-Is/ARBs and 2124 (21%) patients experienced recurrent AKI. Crude rate of recurrent AKI was 6.1 (95% confidence interval [95% CI], 5.9 to 6.4) per 100 person-years off ACE-Is/ARBs and 5.7 (95% CI, 4.9 to 6.5) per 100 person-years on ACE-Is/ARBs. In marginal structural causal inference models that adjusted for baseline and potential time-dependent confounders, exposure to ACE-I/ARB use was not associated with higher incidence of recurrent AKI (adjusted odds ratio, 0.71; 95% CI, 0.45 to 1.12).

CONCLUSIONS

In this study of AKI survivors without heart failure, new use of ACE-I/ARB therapy was not independently associated with increased risk of recurrent hospitalized AKI.

Comparison of Angiotensin-Converting Enzyme Inhibitor and Angiotensin Receptor Blocker Management Strategies Before Cardiac Surgery: A Pilot Randomized Controlled Registry Trial

Background

Postoperative clinical outcomes associated with the preoperative continuation or discontinuation of angiotensin‐converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) before cardiac surgery remain unclear.

Methods and Results

In a single‐center, open‐label, randomized, registry‐based clinical trial, patients undergoing nonemergent cardiac surgery were assigned to ACEI/ARB continuation or discontinuation 2 days before surgery. Among the 584 patients screened, 261 met study criteria and 126 (48.3%) patients were enrolled. In total,121 patients (96% adherence; 60 to continuation and 61 to ACEI/ARB discontinuation) underwent surgery and completed the study protocol, and follow‐up was 100% complete. Postoperative intravenous vasopressor use (78.3% versus 75.4%, P=0.703), vasodilator use (71.7% versus 80.3%, P=0.265), vasoplegic shock (31.7% versus 27.9%, P=0.648), median duration of vasopressor (10 versus 5 hours, P=0.494), and vasodilator requirements (10 versus 9 hours, P=0.469) were not significantly different between the continuation and discontinuation arms. No differences were observed in the incidence of acute kidney injury (1.7% versus 1.6%, P=0.991), stroke (no events, mortality (1.7% versus 1.6%, P=0.991), median duration of mechanical ventilation (6 versus 6 hours, P=0.680), and median intensive care unit length of stay (43 versus 27 hours, P=0.420) between the treatment arms.

Conclusions

A randomized study evaluating the routine continuation or discontinuation of ACEIs or ARBs before cardiac surgery was feasible, and treatment assignment was not associated with differences in postoperative physiological or clinical outcomes. These preliminary findings suggest that preoperative ACEI/ARB management strategies did not affect the postoperative course of patients undergoing cardiac surgery.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02096406.

Associations between preoperative continuation of renin-angiotensin system inhibitor and cardiac surgery-associated acute kidney injury: a propensity score-matching analysis

BACKGROUND

Cardiac surgery-associated acute kidney injury (CSA-AKI) is associated with high risk for complications and mortality. Whether renin-angiotensin system (RAS) inhibitor should be continued or withdrawn in patients with long-term use before cardiac surgery has been lack of consensus.

METHODS

We performed this prospective observational cohort study and recruited cardiac surgery patients in the surgical intensive care units between 2000 and 2011. These patients were divided into users and non-users of RAS inhibitor. Propensity score matching and multivariable models were performed to investigate the association between renal outcome, mortality, and preoperative use of RAS inhibitor.

RESULTS

Preoperative use of RAS inhibitor was identified as the independent protective factor for AKI development (OR 0.41, 95% CI 0.23, 0.63), AKI severity (stage 3 vs. stage 1, OR 0.35, 95% CI 0.18, 0.69), and renal recovery (OR 3.41, 95% CI 1.84, 5.36). Nevertheless, there was no significant protective effect of RAS inhibitor on in-hospital dialysis, in-hospital mortality, and ensuing development of chronic kidney disease (CKD) after AKI. We created a prediction model of CSA-AKI and indicated that preoperative use of RAS inhibitor provided more protective effect in low-risk than high-risk population.

CONCLUSION

Preoperative use of RAS inhibitor was associated with less AKI development and severity, and higher renal recovery. Although more risk reduction of AKI development was shown in low-risk group by our prediction model, continued use of RAS inhibitor before cardiac surgery could provide protective effect in all patients.

Angiotensin axis blockade, acute kidney injury, and perioperative morbidity in patients undergoing colorectal surgery: A retrospective cohort study

Patients undergoing surgery and taking angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) are susceptible to complications related to intraoperative hypotension. Perioperative continuation of such medications in patients undergoing colorectal surgery may be associated with more harm than benefit, as these patients are often exposed to other risk factors which may contribute to intraoperative hypotension. Our objectives were to assess the incidence and severity of postinduction hypotension as well as the rates of acute kidney injury (AKI), 30-day all-cause mortality, 30-day readmission, and hospital length of stay in adult patients undergoing colorectal surgery who take ACEi/ARB.We performed a retrospective chart review of patients undergoing colorectal surgery of ≥4 hour duration at a tertiary care academic medical center between January 2011 and November 2016. The preoperative and intraoperative characteristics as well as postoperative outcomes were compared between patients taking ACEi/ARB and patients not taking these medications.Of the 1020 patients meeting inclusion criteria, 174 (17%) were taking either ACEi or ARB before surgery. Patients taking these medications were more likely to receive both postinduction and intraoperative phenylephrine and ephedrine. The incidences of postoperative AKI (P = .35), 30-day all-cause mortality (P = .36), 30-day hospital readmission (P = .45), and hospital length of stay (P = .25), were not significantly different between the 2 groups.Our results support the current recommendation that ACEi/ARB use is probably safe within the colorectal surgery population during the perioperative period. Intraoperative hypotension should be expected and treated with vasopressors.

[Epidemiology of acute renal failure]

The acute renal failure is common in the hospitalized patients with the incidence is increasing. This results from the aging of the population and the widespread use of nephrotoxic therapies or diagnostic techniques. The acute renal failure is associated with an increased length of stay in hospital and the short and long-term mortality. The most common histological injury is the acute tubular necrosis. Although the most of acute renal failure is recovering, recent works have shown that there is a strong association between an acute renal failure and the increased risk of developing a chronic kidney disease.

Role of renin-angiotensin system in acute kidney injury-chronic kidney disease transition

Acute kidney injury (AKI) can increase the risk of developing incident chronic kidney disease (CKD). The severity, frequency and duration of AKI are crucial predictors of poor renal outcome. A repair process after AKI can be adaptive and kidney recovers completely after a mild injury. However, severe injury will lead to a maladaptive repair, which frequently progresses to nephron loss, vascular rarefaction, chronic inflammation and fibrosis. Although different mechanisms underlying AKI-CKD transition have been extensively discussed, no definite intervention has been proved effective to block or to retard the transition until recently. In CKD, renin-angiotensin system (RAS) inhibitor has been proved effective to slow down disease progression. Furthermore, RAS needs to be highlighted again in AKI-CKD transition because recent animal studies have shown the activation of intra-renal RAS after AKI, and RAS blockade can reduce the ensuing CKD and mortality. In patients with the complete renal recovery after AKI, administration of RAS inhibitor is associated with reduced risk of subsequent CKD as well. In this article, we will demonstrate the role of RAS in AKI-CKD transition comprehensively. We will then emphasize the promising effect of RAS inhibitor on CKD prevention in patients recovering from AKI based on evidence from the bench to clinical research. All of these discussions will contribute to the establishment of reliable monitoring and therapeutic strategies for patients with functional recovery from AKI who can be most easily ignored.

Age modifies the risk factor profiles for acute kidney injury among recently diagnosed type 2 diabetic patients: a population-based study

The incidence of acute kidney injury (AKI) rises with age and is associated with multiple risk factors. Here, we compared the risk factors for AKI between younger and older incident diabetic patients to examine the trends in risk alteration for individual factors across different age groups. Between 2007 and 2013, we selected all incident type 2 diabetic adults from the Taiwan National Health Insurance registry, stratified based on age: young (< 65 years), old (≥ 65 but < 75 years), and older-old (≥ 75 years). All factors with potential renal influence (e.g., comorbidities, medications, and diagnostics/procedures) were recorded during the study period, with a nested case-controlled approach utilized to identify independent risk factors for AKI in each age group. Totally, 930,709 type 2 diabetic patients were categorized as young (68.7%), old (17.7%), or older-old (13.6%). Older-old patients showed a significantly higher incidence of AKI than the old and the young groups. Cardiovascular morbidities (hypertension, atrial fibrillation, acute coronary syndrome, and cerebrovascular disease) were shown to increase the risk of AKI, although the risk declined with increasing age. Chronic obstructive pulmonary disease and receiving cardiac catheterization elevated the risk of AKI preferentially in the older-old/old and older-old group, respectively, while the administration of angiotensin-converting enzyme/α-blocker and angiotensin receptor blocker/calcium channel blocker reduced the risk of AKI preferentially in the older-old and older-old/old group, respectively. In conclusion, our findings highlight the importance of devising age-specific risk factor panels for AKI in patients with recently diagnosed type 2 diabetes.