Association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use prior to major elective surgery and the risk of acute dialysis

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.

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.

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.

Strategies to Reduce Perioperative Nephrotoxicity

Postoperative acute kidney injury (AKI) is a common complication of surgery that is associated with significant adverse outcomes, including increased morbidity and mortality. The perioperative burden of AKI risk factors is complex and potentially large, including high-risk nephrotoxic medications, hypotension, hypovolemia, radiologic contrast, anemia, and surgery-specific factors. Understanding the pathogenesis, risk factors, and potential cumulative impact of perioperative nephrotoxic exposures is particularly important in the prevention and reduction of perioperative AKI. This review outlines the possible strategies to reduce perioperative nephrotoxicity and the development of postoperative AKI.

Renin-angiotensin system blocker use and the risk of acute kidney injury after colorectal cancer surgery: a population-based cohort study

OBJECTIVES

It is unknown whether preoperative use of ACE inhibitors (ACE-I) or angiotensin receptor blockers (ARBs) affects the risk of acute kidney injury (AKI) after colorectal cancer (CRC) surgery. We assessed the impact of preoperative ACE-I/ARB use on risk of AKI after CRC surgery.

DESIGN

Observational cohort study. Patients were divided into three exposure groups-current, former and non-users-through reimbursed prescriptions within 365 days before the surgery. AKI within 7 days after surgery was defined according to the current Kidney Disease Improving Global Outcome consensus criteria.

SETTING

Population-based Danish medical databases.

PARTICIPANTS

A total of 9932 patients undergoing incident CRC surgery during 2005-2014 in northern Denmark were included through the Danish Colorectal Cancer Group Database.

OUTCOME MEASURE

We computed cumulative incidence proportions (risk) of AKI with 95% CIs for current, former and non-users of ACE-I/ARB, including death as a competing risk. We compared current and former users with non-users by computing adjusted risk ratios (aRRs) using log-binomial regression adjusted for demographics, comorbidities and CRC-related characteristics. We stratified the analyses of ACE-I/ARB users to address any difference in impact within relevant subgroups.

RESULTS

Twenty-one per cent were ACE-I/ARB current users, 6.4% former users and 72.3% non-users. The 7-day postoperative AKI risk for current, former and non-users was 26.4% (95% CI 24.6% to 28.3%), 25.2% (21.9% to 28.6%) and 17.8% (17.0% to 18.7%), respectively. The aRRs of AKI were 1.20 (1.09 to 1.32) and 1.16 (1.01 to 1.34) for current and former users, compared with non-users. The relative risk of AKI in current compared with non-users was consistent in all subgroups, except for higher aRR in patients with a history of hypertension.

CONCLUSIONS

Being a current or former user of ACE-I/ARBs is associated with an increased risk of postoperative AKI compared with non-users. Although it may not be a drug effect, users of ACE-I/ARBs should be considered a risk group for postoperative AKI.

Impact of renin-angiotensin system inhibitors continuation versus discontinuation on outcome after major surgery: protocol of a multicenter randomized, controlled trial (STOP-or-NOT trial)

BACKGROUND

Chronic treatment of hypertension or heart failure very often includes an angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) as renin-angiotensin system inhibitors (RASi) treatments. To stop or not to stop these medications before major surgery remains an unresolved issue. The lack of evidence leads to conflicting guidelines with respect to RASi management before major surgery. The purpose of this study is to evaluate the impact of a strategy of RASi continuation or discontinuation on perioperative complications in patients undergoing major non-cardiac surgery.

METHODS

This is a multicenter, open-labeled randomized controlled trial in > 30 French centers. In the experimental group, RASi will be continued while the treatment will be stopped 48 h before the surgery in the control arm. The primary endpoint is a composite endpoint of major complications after surgery. An endpoint adjudication committee will review clinical data and adjudicate efficacy endpoints while blinded to the assigned study drug group. Main analysis will be by intention-to-treat comparing the composite outcome measure at 28 days in the two groups. A total of 2222 patients are planned to detect an absolute complications difference of 5%.

DISCUSSION

The results of the trial should provide robust evidence to anesthesiologists and surgeons regarding management of RASi before major non-cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03374449 . Registered on 11 December 2017.

Prognostic Impact of Angiotensin-Converting Enzyme Inhibitors and Receptor Blockers on Recurrent Ventricular Tachyarrhythmias and Implantable Cardioverter-Defibrillator Therapies

This study sought to assess the prognostic impact of treatment with angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) on recurrences of ventricular tachyarrhythmias in recipients of implantable cardioverter-defibrillators (ICD). Using a large retrospective registry including consecutive ICD recipients with documented episodes of ventricular tachycardia (VT) or fibrillation (VF) from 2002 to 2016, those patients treated with ACEi/ARB were compared with patients without. The primary prognostic endpoint was the first recurrence of ventricular tachyarrhythmias and related ICD therapies at 5 years. Multivariable Cox regression analyses were applied within the entire cohort, and thereafter, Kaplan-Meier analyses were performed in propensity-matched subgroups. A total of 592 consecutive ICD recipients were included (81% treated with ACEi/ARB and 19% without). Although ACEi/ARB was associated with no differences in overall recurrence of ventricular tachyarrhythmias, ACEi/ARB was associated with improved freedom from appropriate ICD therapy within multivariable Cox regressions (hazard ratio = 0.666; P = 0.043), especially in patients with index episodes of VF, left ventricular ejection fraction <35%, coronary artery disease, secondary preventive ICD, and glomerular filtration rate <45 mL/min/1.73 m. In the propensity-matched subgroup, ACEi/ARB still prolonged freedom from appropriate ICD therapies (hazard ratio = 0.380; 95% confidence interval 0.193-0.747; P = 0.005). In conclusion, ACEi/ARB therapy was associated with improved freedom from appropriate ICD therapies.

Preoperative Albuminuria and Intraoperative Chloride Load: Predictors of Acute Kidney Injury Following Major Abdominal Surgery

Background: Postoperative Acute Kidney Injury (AKI) is a common and serious complication associated with significant morbidity and mortality. While several pre- and intra-operative risk factors for AKI have been recognized in cardiac surgery patients, relatively few data are available regarding the incidence and risk factors for perioperative AKI in other surgical operations. The aim of the present study was to determine the risk factors for perioperative AKI in patients undergoing major abdominal surgery. Methods: This was a prospective, observational study of patients undergoing major abdominal surgery in a tertiary care center. Postoperative AKI was diagnosed according to the Acute Kidney Injury Network criteria within 48 h after surgery. Patients with chronic kidney disease stage IV or V were excluded. Logistic regression analysis was used to evaluate the association between perioperative factors and the risk of developing postoperative AKI. Results: Eleven out of 61 patients developed postoperative AKI. Four intra-operative variables were identified as predictors of AKI: intra-operative blood loss (p = 0.002), transfusion of fresh frozen plasma (p = 0.004) and red blood cells (p = 0.038), as well as high chloride load (p = 0.033, cut-off value > 500 mEq). Multivariate analysis demonstrated an independent association between AKI development and preoperative albuminuria, defined as a urinary Albumin to Creatinine ratio ≥ 30 mg·g⁻¹ (OR = 6.88, 95% CI: 1.43–33.04, p = 0.016) as well as perioperative chloride load > 500 mEq (OR = 6.87, 95% CI: 1.46–32.4, p = 0.015). Conclusion: Preoperative albuminuria, as well as a high intraoperative chloride load, were identified as predictors of postoperative AKI in patients undergoing major abdominal surgery.

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.

Perioperative use of angiotensin-converting-enzyme inhibitors and angiotensin receptor antagonists

STUDY OBJECTIVE

Clinical repercussions of perioperative treatment with ACEIs/ARBs.

DESIGN

Systematic review according to PRISMA statement.

SETTING

Perioperative period.

PATIENTS

29 studies 11 cases/cases series, 12 observational studies and 6 randomized studies.

MEASUREMENTS

Arterial blood pressure differences, refractory hypotension, other comorbidities.

MAIN RESULTS

The studies show different results regarding the topics measured. They are divided in the results regarding blood pressure, long term morbidities and effects in neuraxial anesthesia.

CONCLUSIONS

Withholding AECI/ARBs on the morning prior to surgery could be recommended as a potentially effective measure, with a low level of evidence, in order to reduce the appearance of hypotension in the perioperative period of non-cardiac surgery.

Predictors of Perioperative Acute Kidney Injury in Obese Patients Undergoing Laparoscopic Bariatric Surgery: a Single-Centre Retrospective Cohort Study

BACKGROUND

Obesity has been associated with increased risk of perioperative acute kidney injury (AKI). We aim to establish the incidence of AKI among patients undergoing laparoscopic bariatric surgery and identify potential risk factors.

METHODS

Records of 1230 patients who underwent laparoscopic bariatric surgery in a tertiary centre from 1 December 2009 to 31 January 2014 were retrospectively studied. AKI diagnosis was made by comparing the baseline and post-operative serum creatinine to determine the presence of predefined significant change based on the Kidney Disease: Improving Global Outcomes (KDIGO) definition. Univariate analyses were performed to determine significant clinical factors, and multiple logistic regression analysis was subsequently done to determine independent predictors of AKI.

RESULTS

Thirty-five (2.9 %) patients developed AKI during the first 72 h post-surgery. Multivariate logistic regression analysis revealed impaired renal function (OR 10.429, 95 % CI 3.560 to 30.552), use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (OR 3.038, 95 % CI 1.352 to 6.824), and body mass index (OR 1.048, 95 % CI 1.005 to 1.093) as independent predictors of perioperative acute kidney injury in the obese patients who underwent laparoscopic bariatric surgery.

CONCLUSIONS

We found that the incidence of perioperative AKI among patients who underwent laparoscopic bariatric surgery is at 2.9 %. Impaired renal function, use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers and raised body mass index were found to be independent predictors of AKI. Patients with these risk factors could be considered at risk for developing perioperative AKI, and extra perioperative vigilance should be undertaken.

Continuation of Renin-Angiotensin-Aldosterone Inhibitors Does Not Impact Renal Function Among Patients Undergoing Percutaneous Nephrolithotomy

OBJECTIVE

In the perioperative period, renin-angiotensin-aldosterone system (RAAS) inhibitors may result in cardiovascular and renal functional changes. We sought to determine the acute and chronic renal functional and blood pressure effects of continuing or withdrawing angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) after percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

This was a retrospective review of all patients undergoing PCNL at our institution from 2002 to 2013. Patients on either an ACE-I and/or ARB who received an ACE-I and/or ARB during their surgical hospitalization were matched based on sex, age, and body mass index to patients who had their medication withheld during the postoperative period. The two groups were compared.

RESULTS

A total of 2784 patients underwent PCNL during the study period. At the time of PCNL, 15.2% (423/2784) of patients and 6.5% (181/2784) were prescribed an ACE-I and an ARB, respectively. Fifty-nine percent (248/423) of patients on an ACE-I and 66.9% (121/181) on an ARB received their medication during their postoperative hospitalization. There was no significant difference in average length of stay (2 days vs 2 days), perioperative change in glomerular filtration rate, glomerular filtration rate (GFR) (-0.50 mL/min/1.73 m² vs -2.34 mL/min/1.73 m², p = 0.267), change in GFR at 1 month postoperatively (-4.63 mL/min/1.73 m² vs -5.90 mL/min/1.73 m², p = 0.748), or change in GFR at 1 year (-2.08 mL/min/1.73 m² vs -0.13 mL/min/1.73 m², p = 0.267) between patients who received vs withheld their medication during the postoperative stay.

CONCLUSION

It is safe to continue RAAS inhibitors in patients undergoing PCNL during their operative hospitalization.

Acute Kidney Injury in Patients Continued on Renin-Angiotensin System Blockers During Hospitalization

BACKGROUND

Acute kidney injury (AKI) is common in hospitalized patients and is associated with adverse outcomes. This study aimed to evaluate patient characteristics and interventions during hospitalization associated with the development of AKI in patients continued on renin-angiotensin system (RAS) blockers during hospitalization.

METHODS

A retrospective study of 184 adult patients admitted between January 2012 and September 2014 and continued on RAS blockers was conducted. Risk factors for AKI were compared between AKI (n = 92) and non-AKI (n = 92) groups.

RESULTS

Patients who developed hospital-acquired AKI had a higher baseline serum creatinine (1.2 ± 0.4 versus 1 ± 0.3mg/dL, P < 0.001) and lower estimated glomerular filtration rate (54 ± 10 versus 57 ± 7mL/minute/1.73m², P = 0.03) compared with patients who did not develop AKI. Patients who developed AKI were also more likely to be admitted to the intensive care unit, have surgical procedures, have hypotension and be prescribed loop diuretics. The presence of chronic kidney disease and hypotension were risk factors associated with AKI development. In addition, the AKI group had a significantly longer length of stay (14 days versus 8 days, P < 0.0001) and had a higher rate of all-cause hospital mortality (9% versus 1%, P = 0.03).

CONCLUSIONS

Patients with chronic kidney disease, hypotension and those undergoing surgeries were more likely to develop AKI while receiving RAS blockers. During hospitalization, temporary discontinuation of these medications may be warranted in patients with these characteristics.

Evaluation of Short-Term Changes in Serum Creatinine Level as a Meaningful End Point in Randomized Clinical Trials

Observational studies have shown that acute change in kidney function (specifically, AKI) is a strong risk factor for poor outcomes. Thus, the outcome of acute change in serum creatinine level, regardless of underlying biology or etiology, is frequently used in clinical trials as both efficacy and safety end points. We performed a meta-analysis of clinical trials to quantify the relationship between positive or negative short-term effects of interventions on change in serum creatinine level and more meaningful clinical outcomes. After a thorough literature search, we included 14 randomized trials of interventions that altered risk for an acute increase in serum creatinine level and had reported between-group differences in CKD and/or mortality rate ≥3 months after randomization. Seven trials assessed interventions that, compared with placebo, increased risk of acute elevation in serum creatinine level (pooled relative risk, 1.52; 95% confidence interval, 1.22 to 1.89), and seven trials assessed interventions that, compared with placebo, reduced risk of acute elevation in serum creatinine level (pooled relative risk, 0.57; 95% confidence interval, 0.44 to 0.74). However, pooled risks for CKD and mortality associated with interventions did not differ from those with placebo in either group. In conclusion, several interventions that affect risk of acute, mild to moderate, often temporary elevation in serum creatinine level in placebo-controlled randomized trials showed no appreciable effect on CKD or mortality months later, raising questions about the value of using small to moderate changes in serum creatinine level as end points in clinical trials.

Identification of Risk Factors Associated With Postoperative Acute Kidney Injury After Esophagectomy for Esophageal Cancer

OBJECTIVE

To identify risks factors associated with acute kidney injury (AKI) after esophageal cancer surgery.

DESIGN

This was a retrospective study.

SETTING

Single academic center.

PARTICIPANTS

Subjects with non-metastatic esophageal cancer. Patients were excluded if they were younger than 18 years and had missing data.

MEASUREMENTS AND MAIN RESULTS

Primary outcome of the study was AKI according to AKI Network criteria. Demographic and perioperative variables were compared in patients with and without AKI. A multivariate Cox proportional model was used to assess the association between perioperative variables and AKI; p<0.05 was considered statistically significant. AKI was found in 107 (11.9%) of the 898 patients included in the study. The multivariate analysis also showed that BMI (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.03-1.11), number of comorbidities (OR 1.52, 95% CI 1.20-1.93, p = 0.001), and preoperative creatinine concentrations (OR 2.37, 95% CI 1.14-4.92, p = 0.02) were independent predictors for AKI. The use of dexamethasone was associated with a reduced risk for AKI.

CONCLUSIONS

In support of previous reports in the literature, the authors found that AKI was not an uncommon complication after esophageal surgery. Obesity, cardiovascular comorbidities, and high preoperative concentrations were predictors of AKI. Dexamethasone administration during surgery appeared to have a protective effect. This finding opens an opportunity to further study in a randomized controlled trial the efficacy of dexamethasone in the prevention of AKI.

Acute Kidney Injury in Elderly Patients With Chronic Kidney Disease: Do Angiotensin-Converting Enzyme Inhibitors Carry a Risk?

In contrast to angiotensin receptor blockers (ARBs), mainly excreted by the liver, the dosage of angiotensin-converting enzyme (ACE) inhibitors, cleared by the kidney, must be adapted to account for renal clearance in patients with chronic kidney disease (CKD) to avoid acute kidney injury (AKI). Community-acquired AKI and the use of ACE inhibitors or ARBs in the emergency department were retrospectively assessed in 324 patients with baseline stage 3 or higher CKD. After stepwise regression analysis, the use of ACE inhibitors (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.1-3.1; P=.02) and the presence of dehydration (OR, 30.8; 95% CI, 3.9-239.1) were associated with AKI. A total of 45% of patients using ACE inhibitors experienced overdosing, which causes most of the excess risk of AKI. These results suggest that dosage adjustment of ACE inhibitors to renal function or substitution of ACE inhibitors with ARBs could reduce the incidence of AKI. Moreover, ACE inhibitors and ARBs should be stopped in cases of dehydration.

Perioperative Management of Patients Treated with Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Quality Improvement Audit

Previous studies have shown that patients continuing angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers on the day of surgery are more likely to have significant intraoperative hypotension, higher rates of postoperative acute kidney injury and lower incidences of postoperative atrial fibrillation. However, many of these studies were prone to bias and confounding, and questions remain over the validity of these outcomes. This observational, before-and-after quality mprovement audit aimed to assess the effect of withholding these medications on the morning of surgery. We recruited 323 participants, with 83 (26%) having their preoperative angiotensin-converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARB) withheld on the day of surgery. There were only very small Spearman rank-order correlations between time since last dose of these medications (rho −0.12, P=0.057) and intraoperative and recovery room intravenous fluid administration (rho −0.11, P=0.042). There was no statistically significant difference between the continued or withheld groups in vasopressor (metaraminol use 3.5 [1.5–8.3] mg versus 3.5 [1.5–8.5] mg, P=0.67) or intravenous fluid administration (1000 ml [800–1500] ml versus 1000 [800–1500] ml, P=0.096), nor rates of postoperative acute kidney injury (13% vs 18%, P=0.25) or atrial fibrillation (15% versus 18%, P=0.71). This audit found no significant differences in measured outcomes between the continued or withheld ACEi/ARB groups. This finding should be interpreted with caution due to the possibility of confounding and an insufficient sample size. However, as the finding is in contrast to many previous studies, future prospective randomised clinical trials are required to answer this important question.

Characteristics and Outcomes of AKI Treated with Dialysis during Pregnancy and the Postpartum Period

Acute kidney injury (AKI) is a rare complication of pregnancy, but may be associated with significant morbidity and mortality in young and often otherwise healthy women. We conducted a retrospective population-based cohort study of all consecutive pregnancies over a 15-year period (1997-2011) in Ontario, Canada, and describe the incidence and outcomes of AKI treated with dialysis during pregnancy or within 12 weeks of delivery. Of 1,918,789 pregnancies, 188 were complicated by AKI treated with dialysis (incidence: 1 per 10,000 [95% confidence interval, 0.8 to 1.1]). Only 21 of 188 (11.2%) women had record of a preexisting medical condition; however, 130 (69.2%) women experienced a major pregnancy-related complication, including preeclampsia, thrombotic microangiopathy, heart failure, sepsis, or postpartum hemorrhage. Eight women died (4.3% versus 0.01% in the general population), and seven (3.9%) women remained dialysis dependent 4 months after delivery. Low birth weight (<2500 g), small for gestational age, or preterm birth (<37 weeks' gestation) were more common in pregnancies in which dialysis was initiated (35.6% versus 14.0%; relative risk, 3.40; 95% confidence interval, 2.52 to 4.58). There were no stillbirths and fewer than five neonatal deaths (<2.7%) in affected pregnancies compared with 0.1% and 0.8%, respectively, in the general population. In conclusion, AKI treated with dialysis during pregnancy is rare and typically occurs in healthy women who acquire a major pregnancy-related medical condition such as preeclampsia. Many affected women and their babies have good short-term outcomes.

Association between Withholding Angiotensin Receptor Blockers in the Early Postoperative Period and 30-day Mortality

Background:

Despite widespread use, there is limited information to guide perioperative management of angiotensin receptor blockers (ARBs).

Methods:

In this retrospective cohort study, the authors evaluated the patterns of postoperative ARB use in veterans regularly prescribed ARBs admitted for noncardiac surgery at the Veterans Affairs Healthcare system between 1999 and 2011. Multivariable and propensity score–matched Cox proportional hazards models were used to determine the independent effect of failure to resume ARB by postoperative day 2 on the primary outcome of all-cause 30-day mortality.

Results:

Out of 1,167,482 surgical admissions, 30,173 inpatient surgical admissions met inclusion criteria. Approximately 10,205 patients (33.8%) in the cohort did not resume ARB by day 2. Those that resumed ARB had a 30-day mortality rate of 1.3% (260 of 19,968), whereas 3.2% (323 of 10,205) died in the group that withheld ARB. The unadjusted hazard ratio (HR) for 30-day mortality was 2.45 (95% CI, 2.08 to 2.89; P &lt; 0.001) for those that withheld ARB compared with those that resumed, whereas the multivariable adjusted HR was 1.74 (95% CI, 1.47 to 2.06; P &lt; 0.001). When restricted to a propensity score–matched subset of 19,490, the HR was similar (1.47; 95% CI, 1.22 to 1.78; P &lt; 0.001). Withholding ARB in younger patients increased mortality risk (HR = 2.52; 95% CI, 1.69 to 3.76; P &lt; 0.001 for age &lt;60 yr) compared with older patients (HR = 1.42; 95% CI, 1.09 to 1.85; P = 0.01 for age &gt;75 yr).

Conclusions:

Postoperative delay in resuming ARB is common, particularly in patients who are frail after surgery. Withholding ARB is strongly associated with increased 30-day mortality, especially in younger patients, although residual confounding may be present.

Pre- and/or Intra-Operative Prescription of Diuretics, but Not Renin-Angiotensin-System Inhibitors, Is Significantly Associated with Acute Kidney Injury after Non-Cardiac Surgery: A Retrospective Cohort Study

Background and Objectives

Pre- and/or intra-operative use of diuretics, angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin II receptor blockers (ARB) constitutes a potentially modifiable risk factor for postoperative acute kidney injury (AKI). It has been studied whether use of these drugs predicts AKI after cardiac surgery. The objective of this study was to examine whether administration of these agents was independently associated with AKI after non-cardiac surgery.

Design, Setting, Participants, and Measurements

This was a retrospective observational study. Inclusion criteria were adult patients (age ≥ 18) who underwent non-cardiac surgery under general anesthesia from 2007 to 2009 at Kyoto Katsura Hospital. Exclusion criteria were urological surgery, missing creatinine values, and preoperative dialysis. The exposures of interest were pre- and/or intra-operative use of diuretics or ACE-I/ARB. Outcome variables were postoperative AKI as defined by the AKI Network (increase in creatinine ≥ 0.3 mg/dL or 150% within 48 hours, or urine output < 0.5 ml/kg/hour for > 6 hours). Multivariable logistic regression analyses were conducted and adjusted for potential confounders. Propensity scores (PS) for receiving diuretics or ACE-I/ARB therapy were estimated and PS adjustment, PS matching, and inverse probability weighting were performed.

Results

There were 137 AKI cases (5.0%) among 2,725 subjects. After statistical adjustment for patient and surgical characteristics, odds (95% CI) of postoperative AKI were 2.07 (1.10-3.89) (p = 0.02) and 0.89 (0.56-1.42) (p = 0.63) in users of diuretics and ACE-I/ARB, respectively, compared with non-users. PS adjustment, PS matching, and inverse probability weighting yielded similar results. The effect size of diuretics was significantly greater in the patients with lower propensity for diuretic use (p for interaction < 0.1).

Conclusions

Prescription of diuretics, but not ACE-I/ARB, was independently associated with postoperative AKI after non-cardiac surgery, especially in patients with low propensity for diuretic use. It might be reasonable to withhold preoperative diuretics in these patients.

AKI associated with cardiac surgery

Approximately 18% of patients undergoing cardiac surgery experience AKI (on the basis of modern standardized definitions of AKI), and approximately 2%-6% will require hemodialysis. The development of AKI after cardiac surgery portends poor short- and long-term prognoses, with those developing RIFLE failure or AKI Network stage III having an almost 2-fold increase in the risk of death. AKI is caused by a variety of factors, including nephrotoxins, hypoxia, mechanical trauma, inflammation, cardiopulmonary bypass, and hemodynamic instability, and it may be affected by the clinician's choice of fluids and vasoactive agents as well as the transfusion strategy used. The risk of AKI may be ameliorated by avoidance of nephrotoxins, achievement of adequate glucose control preoperatively, and use of goal-directed therapy hemodynamic strategies. Remote ischemic preconditioning is an exciting future strategy, but more work is needed before widespread implementation. Unfortunately, there are no pharmacologic agents known to reduce the risk of AKI or treat established AKI.

Relation of digoxin use in atrial fibrillation and the risk of all-cause mortality in patients ≥65 years of age with versus without heart failure

Previous studies on digoxin use in patients with atrial fibrillation (AF) and the risk of all-cause mortality found conflicting results. We conducted a population-based, retrospective, cohort study of patients aged ≥65 years admitted to a hospital with a primary or secondary diagnosis of AF, in Quebec province, Canada, from 1998 to 2012. The AF cohort was grouped into patients with and without heart failure (HF) and into digoxin and no-digoxin users according to the first prescription filled for digoxin within 30 days after AF hospital discharge. We derived propensity score-matched digoxin and no-digoxin treatment groups for the groups of patients with and without HF, respectively, and conducted multivariable Cox proportional hazards regression analyses to determine association between digoxin use and all-cause mortality. The AF propensity score-matched cohorts of patients with and without HF were well balanced on baseline characteristics. In the propensity score-matched HF group, digoxin use was associated with a 14% greater risk of all-cause mortality (adjusted hazard ratio 1.14, 95% confidence interval 1.10 to 1.17). In the propensity score-matched no-HF group, digoxin use was associated with a 17% greater risk of all-cause mortality (adjusted hazard ratio 1.17, 95% confidence interval 1.14 to 1.19). In conclusion, our retrospective analyses found that digoxin use was associated with a greater risk for all-cause mortality in patients aged ≥65 years with AF regardless of concomitant HF. Large, multicenter, randomized controlled trials or prospective cohort studies are required to clarify this issue.