Association between preoperative statin use and acute kidney injury biomarkers in cardiac surgical procedures

A wide scope, pan-comparative, systematic meta-analysis of the efficacy of prophylactic strategies for cardiac surgery-associated acute kidney injury

Acute kidney injury (AKI) is the most common complication of cardiac surgery. Cardiac surgery-associated AKI (CSA-AKI) is caused by systemic and renal hemodynamic impairment and parenchymal injury. Prophylaxis of CSA-AKI remains an unmet priority, for which preventive strategies based on drug therapies, hydration procedures, and remote ischemic preconditioning (RIPC) have been tested in pre-clinical and clinical studies, with variable success. Contradicting reports and scarce or insufficiently pondered information have blurred conclusions. Therefore, with an aim to contribute to consolidating the available information, we carried out a wide scope, pan-comparative meta-analysis including the accessible information about the most relevant nephroprotective approaches assayed. After a thorough examination of 1892 documents retrieved from PubMed and Web of Science, 150 studies were used for the meta-analysis. Individual odds ratios of efficacy at reducing AKI incidence, need for dialysis, and plasma creatinine elevation were obtained for each alleged protectant. Also, the combined class effect of drug families and protective strategies was also meta-analyzed. Our results show that no drug family or procedure affords substantial protection against CSA-AKI. Only, a mild but significant reduction in the incidence of CSA-AKI by preemptive treatment with dopaminergic and adrenergic drugs, vasodilators, and the RIPC technique. The integrated analysis suggests that single-drug approaches are unlikely to cope with the variety of individual pathophysiological scenarios potentially underlying CSA-AKI. Accordingly, a theragnostic approach involving the etiopathological diagnosis of kidney frailty is necessary to guide research towards the development of pharmacological combinations concomitantly and effectively addressing the key mechanisms of CSA-AKI.

The impact of statin use before intensive care unit admission on patients with acute kidney injury after cardiac surgery

Background: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common and serious complication after cardiac surgery. The influence of statin use before surgery on the renal outcome of patients undergoing cardiac surgery is controversial. The purpose of this study was to evaluate the effect of statins on postoperative renal outcomes in patients undergoing cardiac surgery. Methods: We included CSA-AKI patients in the Medical Information Mart for Intensive Care (MIMIC)-IV database and were divided into statin group and non-statin group according to whether they used statins before entering intensive care units (ICU). The main outcomes were hospitalization and 30-day mortality, and the secondary outcomes were 60-day mortality and 90-day mortality. We used propensity score matching (PSM) to adjust for confounding factors. The 95% confidence interval (CI) and risk ratio (RO) were calculated by the COX proportional regression model. At the same time, stratified analysis was used to explore whether the relationship between the statins use before intensive care units and mortality was different in each subgroup and whether the relationship between different doses of Atorvastatin and mortality was different. Result: We identified 675 pre-ICU statin users and 2095 non-statin users. In the COX proportional regression model, pre-ICU statin use was associated with decreased in-hospital (HR = 0.407, 95%confidence interval 0.278-0.595, p < 0.001) and 30-day mortality (HR = 0.407, 95%CI 0.279-0.595, p < 0.001). The survival rate of patients who took statins before entering ICU was significantly higher than that of those who did not use statins at 30 days, 60 days and 90 days. There is a significant interaction between patients with aged>65 years (HR = 0.373, 95%CI 0.240-0.581, p < 0.001), Acute kidney injury grade I (HR = 0.244, 95%CI 0.118-0.428, p < 0.001), and without post-myocardial infarction syndrome (HR = 0.344, 95%CI 0.218-0.542, p < 0.001). The mortality in hospital and 60 days of CSA-AKI patients treated with ≥80 mg Atorvastatin before operation was significantly reduced (p < 0.05). Conclusion: The pre-ICU statin use was significantly associated with decreased risk in hospital and 30-day mortality. The preoperative use of ≥80 mg Atorvastatin may improve the prognosis of CSA-AKI.

Long-Term Preoperative Atorvastatin or Rosuvastatin Use in Adult Patients before CABG Does Not Increase Incidence of Postoperative Acute Kidney Injury: A Propensity Score-Matched Analysis

Background: Acute kidney injury (AKI) is among the expected complications of cardiac surgery. Statins with pleiotropic anti-inflammatory and antioxidant effects may be effective in the prevention of AKI. However, the results of studies on the efficacy and safety of statins are varied and require further study. Methods: We conducted a retrospective cohort study to evaluate long-term preoperative intake of atorvastatin and rosuvastatin on the incidence of AKI, based on the “Kidney Disease: Improving Global Outcomes” (KDIGO) criteria in the early postoperative period after coronary artery bypass graft surgery (CABG). We performed propensity score matching to compare the findings in our study groups. The incidence of AKI was assessed on day 2 and day 4 after the surgery. Results: The analysis included 958 patients after CABG. After 1:1 individual matching, based on propensity score, the incidence of AKI was comparable both on day 2 after the surgery (7.4%) between the atorvastatin group and rosuvastatin group (6.5%) (OR: 1.182; 95%Cl 0.411–3.397; p = 0.794), and on postoperative day 4 between the atorvastatin group (3.7%) and the rosuvastatin group (4.6%) (OR: 0.723, 95%Cl 0.187–2.792; p = 0.739). Additionally, there were no statistically significant differences in terms of incidence of AKI after 1:1 individual matching, based on propensity score, between the rosuvastatin group and the control group both on postoperative day 2 (OR: 0.692; 95%Cl 0.252–1.899; p = 0.611) and day 4 (OR: 1.245; 95%Cl 0.525–2.953; p = 0.619); as well as between the atorvastatin group and the control group both on postoperative day 2 (OR: 0.549; 95%Cl 0.208–1.453; p = 0.240) and day 4 (OR: 0.580; 95%Cl 0.135–2.501; p = 0.497). Conclusion: Long-term statin use before CABG did not increase the incidence of postoperative AKI. Further, we revealed no difference in the incidence of post-CABG AKI between the atorvastatin and rosuvastatin groups.

Association Between Preoperative Statin Exposure and Acute Kidney Injury in Adult Patients Undergoing Cardiac Surgery

OBJECTIVES

The existing literature has shown conflicting results regarding the association between preoperative statin exposure and the risk of postoperative cardiac surgery-associated acute kidney injury (CSA-AKI).

DESIGN

A single-center retrospective observational study.

SETTING

A single, large, tertiary care center.

PARTICIPANTS

Adult patients undergoing open cardiac surgery between January 1, 2012 and January 1, 2019.

INTERVENTIONS

AKI was defined using the Kidney Disease: Improving Global Outcomes criteria. A multivariate logistic regression analysis and propensity score-matched analysis were used to study the association.

MEASUREMENTS AND MAIN RESULTS

A total of 58,399 patient charts were retrospectively reviewed. The preoperative statin exposure cohort had a lower prevalence of all stages of CSA-AKI (30.7% v 36.3%, p < 0.001) and stage 3 CSA-AKI (0.9% v 2.1%, p < 0.001). After adjusting for confounding factors, preoperative statin exposure was a protective factor against all stages of postoperative CSA-AKI (odds ratio [OR], 0.885, 95% confidence interval [CI], 0.852-0.920, p < 0.001) and stage 3 CSA-AKI in adults (OR, 0.671, 95% CI, 0.567-0.795, p < 0.001). A propensity score-matched analysis showed that the preoperative statin exposure cohort had a lower risk of all stages of postoperative CSA-AKI (30.7% v 35.3%, p < 0.001) and stage 3 CSA-AKI (0.9% v 2.2%, p < 0.001) than the control cohort.

CONCLUSIONS

Preoperative statin exposure was associated with all stages of postoperative CSA-AKI and stage 3 CSA-AKI.

Optimal timing of renal replacement therapy for favourable outcome in patients of acute renal failure following cardiac surgery

Objectives

Acute renal failure is a serious complication following cardiac surgery. This may lead to fatal outcome if not treated timely. Continuous renal replacement therapy (RRT) has shown improvement in outcome. There is no clear consensus on the timing of the initiation of RRT in these patients. This study evaluates the factors predicting favourable outcome in this group of patients.

Methods

Patients undergoing cardiac surgery between January 2015 and December 2018 are included in this retrospective study. RRT is required in 24 patients out of 2254 operated during this period. Patients are divided into groups, survivors (group 1, n = 8) and dead (group 2, n = 16). The preoperative information is accessed from the hospital information system and intensive care unit data. Multivariate analysis of pre continuous renal replacement therapy (CRRT) bicarbonate level, pH, potassium, time of initiating CRRT and central venous pressure is performed.

Results

The incidence of acute renal failure requiring RRT is 1.06%. Patients in two groups were similar in demographics and presence of risk factors. There was difference in the pre RRT bicarbonate level (p = 0.007). On multivariate analysis, pre RRT bicarbonate levels predict survival (p = 0.003). ROC curve for pre RRT bicarbonate predicts survival for value above 16.83 mg/dl with 80% sensitivity and 78.6% specificity.

Conclusion

Bicarbonate level in blood predicts the best evidence for initiating the renal replacement therapy in of acute renal failure following cardiac surgery. When urine output drops to < 0.5 ml/kg and not responding to infusion of furosemide, RRT must be initiated at sodium bicarbonate in blood above 16.9 mg%.

Biomarkers of Acute and Chronic Kidney Disease

The current unidimensional paradigm of kidney disease detection is incompatible with the complexity and heterogeneity of renal pathology. The diagnosis of kidney disease has largely focused on glomerular filtration, while assessment of kidney tubular health has notably been absent. Following insult, the kidney tubular cells undergo a cascade of cellular responses that result in the production and accumulation of low-molecular-weight proteins in the urine and systemic circulation. Modern advancements in molecular analysis and proteomics have allowed the identification and quantification of these proteins as biomarkers for assessing and characterizing kidney diseases. In this review, we highlight promising biomarkers of kidney tubular health that have strong underpinnings in the pathophysiology of kidney disease. These biomarkers have been applied to various specific clinical settings from the spectrum of acute to chronic kidney diseases, demonstrating the potential to improve patient care.

Acute kidney injury after cardiac surgery: prevalence, impact and management challenges

Acute kidney injury (AKI) is a major medical problem that is of particular concern after cardiac surgery. Perioperative AKI is independently associated with an increase in short-term morbidity, costs of treatment, and long-term mortality. In this review, we explore the definition of cardiac surgery-associated acute kidney injury (CSA-AKI) and identify diverse mechanisms and risk factors contributing to the renal insult. Current theories of the pathophysiology of CSA-AKI and description of its clinical course will be addressed in this review. Data on the most promising renal protective strategies in cardiac surgery, from well-designed studies, will be scrutinized. Furthermore, diagnostic tools such as novel biomarkers of AKI and their potential utility will be discussed.

Preoperative Statin Use Not Associated With Improved Outcomes After Ascending Aortic Repair

Statins have potent pleiotropic effects that have been correlated with improved perioperative cardiovascular surgery outcomes. We hypothesize that statins may improve morbidity and mortality after ascending aortic surgery. Within a statewide database consisting of 19 centers a total of 1804 patients had ascending aortic repair with or without aortic valve replacement (2004-2016). Patients were stratified by preoperative statin therapy for analysis. To account for baseline differences, patients were propensity matched in a 1:1 fashion by baseline characteristics. Patient characteristics and outcomes were analyzed by paired analysis. Of 1804 patients undergoing ascending aortic repair, 35% took statins preoperatively. After matching, 386 patients in each group were well matched with no statistically significant baseline or operative differences. There was no statistically significant difference in outcomes between patients taking statins preoperatively and those not taking statins, including operative mortality (3.6% vs 3.1%, P = 0.68) and major morbidity (18.4% vs 17.1%, P = 0.62). Postoperative atrial fibrillation (27.2% vs 28.5%, P = 0.71) and acute kidney injury (3.1% vs 4.2%, P = 0.41) also showed no statistically significant difference. Statins have no apparent clinical impact on perioperative outcomes after ascending aortic aneurysm repair. Considering recent evidence suggesting statins may increase perioperative risk of acute kidney injury, there is insufficient evidence to recommend starting preoperative statin before ascending aortic repair.

TIMP-2*IGFBP7 (Nephrocheck®) Measurements at Intensive Care Unit Admission After Cardiac Surgery are Predictive for Acute Kidney Injury Within 48 Hours

BACKGROUND/AIMS

Acute kidney injury (AKI) is a postoperative complication after cardiac surgery with a high impact on mortality and morbidity. Nephrocheck® [TIMP-2*IGFBP7] determines markers of tubular stress, which occurs prior to tubular damage. It is unknown at which time-point [TIMP-2*IGFBP7] measurement should be performed to ideally predict AKI. We investigated the association of [TIMP-2*IGFBP7] at various time-points with the incidence of AKI in patients undergoing elective cardiac surgery including cardio-pulmonary bypass.

METHODS

In a prospective cohort study, serial blood and urine samples were collected from 150 patients: pre-operative, at ICU-admission, 24h and 48h post-surgery. AKI was defined as Serum-Creatinine rise >0.3 mg/dl within 48hrs. Urinary [TIMP-2*IGFBP7] was measured at pre-operative, ICU-admission and 24h post-surgery; medical staff was kept blinded to these results.

RESULTS

A total of 35 patients (23.5%) experienced AKI, with a higher incidence in those with high [TIMP-2*IGFBP7] values at ICU admission (57.1% vs. 10.1%, p<0.001). In logistic regression [TIMP-2*IGFBP7] at ICU admission was independently associated with the occurrence of AKI (Odds Ratio 11.83; p<0.001, C-statistic= 0.74) after adjustment for EuroSCORE II and CBP-time.

CONCLUSIONS

Early detection of elevated [TIMP-2*IGFBP7] at ICU admission was strongly predictive for postoperative AKI and appeared to be more precise as compared to subsequent measurements.

Effect of perioperative statin therapy on renal outcome in patients undergoing cardiac surgery: A meta-analysis of randomized controlled trials

BACKGROUND

Acute renal injury (AKI) is a common renal complication after cardiac surgery. The aim of this study was to determine the effect of perioperative statin therapy (PST) on postoperative renal outcome in patients undergoing cardiac procedures.

METHODS

We searched for the reports that evaluating the effect of PST on renal outcomes after cardiac surgery between March 1983 and June 2016 in the electronic database Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE/PubMed, and EMBASE/OVID.

RESULTS

Nine randomized controlled trials (RCTs) enrolling 2832 patients, with 1419 in the PST group and 1413 in the control group, were included in this meta-analysis. Our results suggested that PST increased the incidence of postoperative renal complication (relative risk [RR] 1.18, 95% confidence interval [CI] 1.01-1.36, P = .03) with low heterogeneity (I = 30%, P = .18). Six studies with 3116 patients detected no significant difference in severe renal complication between PST and control groups (RR 1.23, 95%CI 0.84-1.79, P = .28). Postoperative serum creatinine (sCr) at 48 hours was shown to be higher in the PST group (mean difference [MD] 0.03, 95% CI 0.03-0.03; P < .01). The length of hospital stay was decreased slightly by 0.59 day in the PST group (95% CI -0.85 to -0.33; P < .01).

CONCLUSIONS

Perioperative statin therapy seems to jeopardize short-term renal outcome in patients undergoing cardiac surgery, but the occurrence of severe renal complication was not affected.

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

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

Stratification and Risk Reduction of Perioperative Acute Kidney Injury

Perioperative acute kidney injury (AKI) is associated with an increased morbidity and mortality. The incidence of AKI varies depending on preoperative risk factors and the surgical setting. Preoperative risk stratification is critical for informed consent and perioperative planning. Perioperative renal protection strategies are potentially invaluable in the prevention of AKI. Current advances in the development of biomarkers may offer the opportunity for early diagnosis and the implementation of therapeutic strategies. Increased awareness and concerted efforts by all perioperative physicians are needed to provide an improved outcome for surgical patients.

Perioperative statin therapy in cardiac surgery: a meta-analysis of randomized controlled trials

BACKGROUND

Several studies suggest beneficial effects of perioperative statin therapy on postoperative outcome after cardiac surgery. However, recent randomized controlled trials (RCTs) show potential detrimental effects. The objective of this systematic review is to examine the association between perioperative statin therapy and clinical outcomes in cardiac surgery patients.

METHODS

Electronic databases were searched up to 1 November 2016 for RCTs of preoperative statin therapy versus placebo or no treatment in adult cardiac surgery. Postoperative outcomes were acute kidney injury, atrial fibrillation, myocardial infarction, stroke, infections, and mortality. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) using fixed-effects meta-analyses. Primary analysis was restricted to trials with low risk of bias according to Cochrane methodology, and sensitivity analyses examined whether the risk of bias of included studies was associated with different results. We performed trial sequential analysis (TSA) to test the strength of the results.

RESULTS

We included data from 23 RCTs involving 5102 patients. Meta-analysis of trials with low risk of bias showed that statin therapy was associated with an increase in acute kidney injury (314 of 1318 (23.82%) with statins versus 262 of 1319 (19.86%) with placebo; OR 1.26 (95%CI 1.05 to 1.52); p = 0.01); these results were supported by TSA. No difference in postoperative atrial fibrillation, myocardial infarction, stroke, infections, or mortality was present. On sensitivity analysis, statin therapy was associated with a slight increase in hospital mortality. Meta-analysis including also trials with high or unclear risk of bias showed no beneficial effects of statin therapy on any postoperative outcomes.

CONCLUSIONS

There is no evidence that statin therapy in the days prior to cardiac surgery is beneficial for patients' outcomes. Particularly, statins are not protective against postoperative atrial fibrillation, myocardial infarction, stroke, or infections. Statins are associated with a possible increased risk of acute kidney injury and a detrimental effect on hospital survival could not be excluded. Future RCTs should further evaluate the safety profile of this therapy in relation to patients' outcomes and assess the more appropriate time point for discontinuation of statins before cardiac surgery.

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.

Prediction and Prevention of Acute Kidney Injury after Cardiac Surgery

The incidence of acute kidney injury after cardiac surgery (CS-AKI) ranges from 33% to 94% and is associated with a high incidence of morbidity and mortality. The etiology is suggested to be multifactorial and related to almost all aspects of perioperative management. Numerous studies have reported the risk factors and risk scores and novel biomarkers of AKI have been investigated to facilitate the subclinical diagnosis of AKI. Based on the known independent risk factors, many preventive interventions to reduce the risk of CS-AKI have been tested. However, any single preventive intervention did not show a definite and persistent benefit to reduce the incidence of CS-AKI. Goal-directed therapy has been considered to be a preventive strategy with a substantial level of efficacy. Many pharmacologic agents were tested for any benefit to treat or prevent CS-AKI but the results were conflicting and evidences are still lacking. The present review will summarize the current updated evidences about the risk factors and preventive strategies for CS-AKI.

Application of new acute kidney injury biomarkers in human randomized controlled trials

The use of novel biomarkers of acute kidney injury (AKI) in clinical trials may help evaluate treatments for AKI. Here we explore potential applications of biomarkers in simulated clinical trials of AKI using data from the TRIBE-AKI multicenter, prospective cohort study of patients undergoing cardiac surgery. First, in a hypothetical trial of an effective therapy at the time of acute tubular necrosis to prevent kidney injury progression, use of an indirect kidney injury marker such as creatinine compared to a new direct biomarker of kidney injury reduces the proportion of true acute tubular necrosis cases enrolled. The result is a lower observed relative risk reduction with the therapy, and lower statistical power to detect a therapy effect at a given sample size. Second, the addition of AKI biomarkers (interleukin-18 and NGAL) to clinical risk factors as eligibility criteria for trial enrollment in early AKI has the potential to increase the proportion of patients who will experience AKI progression and reduce trial cost. Third, we examine AKI biomarkers as outcome measures for the purposes of identifying therapies that warrant further testing in larger, multicenter, multi-country trials. In the hypothetical trial of lower cardiopulmonary bypass time to reduce the risk of postoperative AKI, the sample size required to detect a reduction in AKI is lower if new biomarkers are used to define AKI rather than serum creatinine. Thus, incorporation of new biomarkers of AKI has the potential to increase statistical power, decrease the sample size, and lower the cost of AKI trials.

Validation of administrative database codes for acute kidney injury in kidney transplant recipients

Background

Validation studies of acute kidney injury (AKI) diagnostic codes performed in the general population have shown poor sensitivity, but the accuracy of such codes in the kidney transplant population remains unknown.

Objective

The objective of this study is to determine the accuracy of AKI diagnostic codes in kidney transplant recipients. We hypothesized that the sensitivity of diagnostic codes would be significantly greater in the kidney transplant population since these patients are closely followed by nephrologists and are more likely to have serum creatinine measured.

Design

The design is a population-based retrospective cohort study using healthcare administrative and laboratory databases.

Setting

The setting is in Southwestern Ontario and Ottawa, Ontario, Canada, from 2003 to 2012.

Patients

We included first-time kidney transplant recipients admitted to hospital for whom serum creatinine was measured in hospital and within 6 months prior (n = 524).

Methods

Patients meeting the Acute Kidney Injury Network (AKIN) classification serum creatinine change criteria were classified as having AKI. We determined the sensitivity, specificity, and negative and positive predictive values for the ICD-10-CA code for AKI when present as an admission diagnosis, most responsible diagnosis, or any diagnosis compared to a reference standard of AKI defined by the AKIN criteria (stage 1 or greater, stage 2 or greater, or stage 3).

Results

Forty-five percent of included kidney transplant patients had a diagnosis of AKI. The most sensitive coding algorithm (reference standard AKIN stage 2 or greater, ICD-10 code present as any diagnosis) had a sensitivity of 42.1 % (95 % CI 31.7, 53.3), a specificity of 90.6 % (95 % CI 87.6, 93.0), and a positive likelihood ratio of 4.5. The median (IQR) rise in serum creatinine from baseline in patients with and without AKI codes was 104 (57 to 158) μmol/L and 16 (−3 to 41) μmol/L, respectively (Mann-Whitney test, p < 0.0001).

Limitations

The low sensitivity of the AKI code may be due to an alternative diagnosis of acute rejection being assigned in certain cases. The cause of AKI could not be determined.

Conclusions

Similar to the general population, the ICD-10 N17x code misses many kidney transplant patients with AKI during their hospitalization. This makes the code unusable for studying the incidence and consequences of AKI in hospitalized kidney transplant patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s40697-016-0108-7) contains supplementary material, which is available to authorized users.

High-Dose Perioperative Atorvastatin and Acute Kidney Injury Following Cardiac Surgery: A Randomized Clinical Trial

IMPORTANCE

Statins affect several mechanisms underlying acute kidney injury (AKI).

OBJECTIVE

To test the hypothesis that short-term high-dose perioperative atorvastatin would reduce AKI following cardiac surgery.

DESIGN, SETTING, AND PARTICIPANTS

Double-blinded, placebo-controlled, randomized clinical trial of adult cardiac surgery patients conducted from November 2009 to October 2014 at Vanderbilt University Medical Center.

INTERVENTIONS

Patients naive to statin treatment (n = 199) were randomly assigned 80 mg of atorvastatin the day before surgery, 40 mg of atorvastatin the morning of surgery, and 40 mg of atorvastatin daily following surgery (n = 102) or matching placebo (n = 97). Patients already taking a statin prior to study enrollment (n = 416) continued taking the preenrollment statin until the day of surgery, were randomly assigned 80 mg of atorvastatin the morning of surgery and 40 mg of atorvastatin the morning after (n = 206) or matching placebo (n = 210), and resumed taking the previously prescribed statin on postoperative day 2.

MAIN OUTCOMES AND MEASURES

Acute kidney injury defined as an increase of 0.3 mg/dL in serum creatinine concentration within 48 hours of surgery (Acute Kidney Injury Network criteria).

RESULTS

The data and safety monitoring board recommended stopping the group naive to statin treatment due to increased AKI among these participants with chronic kidney disease (estimated glomerular filtration rate <60 mL/min/1.73 m2) receiving atorvastatin. The board later recommended stopping for futility after 615 participants (median age, 67 years; 188 [30.6%] were women; 202 [32.8%] had diabetes) completed the study. Among all participants (n = 615), AKI occurred in 64 of 308 (20.8%) in the atorvastatin group vs 60 of 307 (19.5%) in the placebo group (relative risk [RR], 1.06 [95% CI, 0.78 to 1.46]; P = .75). Among patients naive to statin treatment (n = 199), AKI occurred in 22 of 102 (21.6%) in the atorvastatin group vs 13 of 97 (13.4%) in the placebo group (RR, 1.61 [0.86 to 3.01]; P = .15) and serum creatinine concentration increased by a median of 0.11 mg/dL (10th-90th percentile, -0.11 to 0.56 mg/dL) in the atorvastatin group vs by a median of 0.05 mg/dL (10th-90th percentile, -0.12 to 0.33 mg/dL) in the placebo group (mean difference, 0.08 mg/dL [95% CI, 0.01 to 0.15 mg/dL]; P = .007). Among patients already taking a statin (n = 416), AKI occurred in 42 of 206 (20.4%) in the atorvastatin group vs 47 of 210 (22.4%) in the placebo group (RR, 0.91 [0.63 to 1.32]; P = .63).

CONCLUSIONS AND RELEVANCE

Among patients undergoing cardiac surgery, high-dose perioperative atorvastatin treatment compared with placebo did not reduce the risk of AKI overall, among patients naive to treatment with statins, or in patients already taking a statin. These results do not support the initiation of statin therapy to prevent AKI following cardiac surgery.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00791648.

Vascular Surgery Kidney Injury Predictive Score: A Historical Cohort Study

OBJECTIVES

To develop a risk-prediction model for acute kidney injury (AKI) in patients undergoing vascular surgery.

DESIGN

A retrospective cohort study.

SETTING

A tertiary referral center.

PARTICIPANTS

Participants included 845 adult patients who underwent vascular surgery between January 3, 2003, and May 29, 2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The median age of patients was 72 years (interquartile range 65-80 years), and 653 patients (77%) were male. AKI developed in 258 (30.5%) patients. Patients with AKI had lower estimated glomerular filtration rates (60±21 v 72±21, p<0.001), were older (73 [68-78] years v 71 [65-80] years, p = 0.01), had a higher prevalence of hypertension (81% v 73%, p = 0.02), and were more likely to undergo emergency surgery (5% v 2%, p = 0.02). Patients with AKI also received more diuretics (p<0.001) and β-blockers (p = 0.003) prior to surgery. The multivariate AKI risk-prediction model with preoperative variables (estimated glomerular filtration rate, previous vascular interventions, use of preoperative diuretics and β-blockers, and emergency surgery) showed an area under the receiver operating characteristic curve of 0.67 (95% confidence interval, 0.628-0.710); a model with additional intraoperative variables (procedure duration, fluid balance, and plasma and platelet transfusion) had an area under the receiver operating characteristic curve of 0.72 (95% confidence interval, 0.685-0.760).

CONCLUSIONS

As AKI is a very common complication after vascular surgery, a risk-prediction model was derived to assess the likelihood of postoperative AKI. If validated in an independent cohort, this model may be used to facilitate targeted interventions in vascular surgery patients at high risk for AKI.

Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) represents an important adverse effect of contrast media (CM) administration. Contrast-induced nephropathy is associated with prolonged hospitalization as well as increased cardiovascular morbidity, renal morbidity, and all-cause mortality. Several risk factors may predict CIN incidence, and various scores and ratios have been proposed to identify high-risk patients. Novel biomarkers may provide an earlier diagnosis of CIN. A multifactorial approach is required for CIN prevention including hydration, administration of low- or iso-osmolar CM, minimizing CM volume, and statin administration. Renal function may deteriorate after CM administration, even in the absence of CIN. Therefore, this deterioration may not be an “all or none” phenomenon; it may well occur in many patients receiving CM, with/without CIN, and may prove to be an underestimated risk factor. Patients should be followed up for longer periods as outpatients after CM exposure to assess kidney function and predict subsequent increased morbidity and mortality.