Preoperative statin administration is associated with lower mortality and decreased need for postoperative hemodialysis in patients undergoing coronary artery bypass graft surgery

Preoperative statin therapy for adults undergoing cardiac surgery

BACKGROUND

Despite significant advances in surgical techniques and perioperative care, people undertaking cardiac surgery due to cardiovascular disease are more prone to the development of postoperative adverse events. Statins (5-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase inhibitors) are well-known for their anti-inflammatory and antioxidant effects and are established for primary and secondary prevention of coronary artery disease. In addition, statins are thought to have clinical benefits in perioperative outcomes in people undergoing cardiac surgery. This review is an update of a review that was first published in 2012 and updated in 2015.

OBJECTIVES

To evaluate the benefits and harms of preoperative statin therapy in adults undergoing cardiac surgery compared to standard of care or placebo.

SEARCH METHODS

We performed a search of the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 9, 2023), Ovid MEDLINE (1980 to 14 September 2023), and Ovid Embase (1980 to 2023 (week 36)). We applied no language restrictions.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) comparing any statin treatment before cardiac surgery, for any given duration and dose, versus no preoperative statin therapy (standard of care) or placebo. We excluded trials without a registered trial protocol and trials without approval by an institutional ethics committee.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology. Primary outcomes were short-term mortality and major adverse cardiovascular events. Secondary outcomes were myocardial infarction, atrial fibrillation, stroke, renal failure, length of intensive care unit (ICU) stay, length of hospital stay and adverse effects related to statin therapy. We reported effect measures as risk ratios (RRs) or mean differences (MDs) with corresponding 95% confidence intervals (CIs). We used the RoB 1 tool to assess the risk of bias in included trials, and GRADE to assess the certainty of the evidence.

MAIN RESULTS

We identified eight RCTs (five new to this review) including 5592 participants. Pooled analysis showed that statin treatment before surgery may result in little to no difference in the risk of postoperative short-term mortality (RR 1.36, 95% CI 0.72 to 2.59; I2 = 0%; 6 RCTs, 5260 participants; low-certainty evidence; note 2 RCTs reported 0 events in both groups so RR calculated from 4 RCTs with 5143 participants). We are very uncertain about the effect of statins on major adverse cardiovascular events (RR 0.93, 95% CI 0.77 to 1.13; 1 RCT, 2406 participants; very low-certainty evidence). Statins probably result in little to no difference in myocardial infarction (RR 0.88, 95% CI 0.73 to 1.06; I2 = 0%; 5 RCTs, 4645 participants; moderate-certainty evidence), may result in little to no difference in atrial fibrillation (RR 0.87, 95% CI 0.72 to 1.05; I2 = 60%; 8 RCTs, 5592 participants; low-certainty evidence), and may result in little to no difference in stroke (RR 1.47, 95% CI 0.90 to 2.40; I2 = 0%; 4 RCTs, 5143 participants; low-certainty evidence). We are very uncertain about the effect of statins on renal failure (RR 1.04, 95% CI 0.80 to 1.34; I2 = 57%; 4 RCTs, 4728 participants; very low-certainty evidence). Additionally, statins probably result in little to no difference in length of ICU stay (MD 1.40 hours, 95% CI -1.62 to 4.41; I2 = 43%; 3 RCTs, 4528 participants; moderate-certainty evidence) and overall hospital stay (MD -0.31 days, 95% CI -0.64 to 0.03; I2 = 84%; 5 RCTs, 4788 participants; moderate-certainty evidence). No study had any individual risk of bias domain classified as high. However, two studies were at high risk of bias overall given the classification of unclear risk of bias in three domains.

AUTHORS' CONCLUSIONS

In this updated Cochrane review, we found no evidence that statin use in the perioperative period of elective cardiac surgery was associated with any clinical benefit or worsening, when compared with placebo or standard of care. Compared with placebo or standard of care, statin use probably results in little to no difference in MIs, length of ICU stay and overall hospital stay; and may make little to no difference to mortality, atrial fibrillation and stroke. We are very uncertain about the effects of statins on major harmful cardiac events and renal failure. The certainty of the evidence validating this finding varied from moderate to very low, depending on the outcome. Future trials should focus on assessing the impact of statin therapy on mortality and major adverse cardiovascular events.

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.

Factors affecting mortality after coronary bypass surgery: a scoping review

Objectives

Previous research reports numerous factors of post-operative mortality in patients undergoing isolated coronary artery bypass graft surgery. However, this evidence has not been mapped to the conceptual framework of care improvement. Without such mapping, interventions designed to improve care quality remain unfounded.

Methods

We identified reported factors of in-hospital mortality post isolated coronary artery bypass graft surgery in adults over the age of 19, published in English between January 1, 2000 and December 31, 2019, indexed in PubMed, CINAHL, and EMBASE. We grouped factors and their underlying mechanism for association with in-hospital mortality according to the augmented Donabedian framework for quality of care.

Results

We selected 52 factors reported in 83 articles and mapped them by case-mix, structure, process, and intermediary outcomes. The most reported factors were related to case-mix (characteristics of patients, their disease, and their preoperative health status) (37 articles, 27 factors). Factors related to care processes (27 articles, 12 factors) and structures (11 articles, 6 factors) were reported less frequently; most proposed mechanisms for their mortality effects.

Conclusions

Few papers reported on factors of in-hospital mortality related to structures and processes of care, where intervention for care quality improvement is possible. Therefore, there is limited evidence to support quality improvement efforts that will reduce variation in mortality after coronary artery bypass graft surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01784-z.

The Impact of Statins before High-Risk CABG on Postoperative Multiple Organ Function

Background

The purpose of this cohort study was to investigate the independent relationship between preoperative statin therapy (PST) and postoperative severe multiorgan failure, measured by the Sequential Organ Failure Assessment (SOFA) maximum greater than 11, in high-risk patients undergoing isolated coronary artery bypass grafting (CABG).

Methods

The present study is a perspective, single-center, cohort analysis enrolling high-risk patients undergoing CABG from Jan 1, 2018, to Dec 31, 2018, in Beijing Anzhen hospital.

Results

Among a total of 880 high-risk patients undergoing isolated CABG included in this study, 503 (57.2%) experienced statin therapy before CABG. The SOFA maximum was significantly lower in the PST group compared with the control group (7.8 ± 3.0 v 9.2 ± 3.4, P < 0.0001). Multivariate logistic regression analysis demonstrated the incidence of the severe multiorgan dysfunction, measured by SOFA maximum ≥11, was dramatically reduced in the PST group (OR, 0.68, 95% CI 0.50-0.92, P=0.013). Furthermore, preoperative statin therapy (PST) might be associated with a decreased risk of postoperative major adverse cardiovascular and cerebral events and acute kidney injury, but an increased risk of postoperative hepatic inadequacy.

Conclusion

SOFA maximum was significantly lower in the PST group compared with the control group and the incidence of the severe multiorgan dysfunction was dramatically reduced in the PST group. The findings of this study might shed new light on questions of positive or negative effects of PST on multiple organ function after high-risk CABG, so as to ultimately improve high-risk patient in-hospital outcomes from CABG.

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

Background Although many patients with coronary artery disease are using statins before off-pump coronary artery bypass grafting ( OPCAB ) following current guidelines, recent studies have raised concerns regarding adverse effects of preoperative statins on postoperative kidney function. We evaluated the effects of preoperative statins on acute kidney injury ( AKI ) after OPCAB . Methods and Results We enrolled 1783 consecutive OPCAB patients in either a statin or nonstatin group based on preoperative use of statins. Propensity scores were used to adjust the differences between the groups. The primary outcome was incidence of postoperative AKI according to Kidney Disease: Improving Global Outcomes criteria. To evaluate the dose-related renal effects of statins, the statin group was divided into low- and moderate- or higher dose groups based on preoperative statin dose. The incidence of postoperative AKI was 15.7% and 13.5% in the nonstatin and statin groups, respectively, and preoperative statins did not increase the incidence of postoperative AKI (odds ratio: 0.84; 95% CI, 0.61-1.15; P=0.27). In dose-related analysis, the moderate- or higher dose group showed lower incidence of postoperative AKI in comparison with the nonstatin group (odds ratio: 0.61; 95% CI, 0.39-0.95; P=0.03). However, no difference was found between low-dose and nonstatin groups (odds ratio: 1.17; 95% CI, 0.75-1.84; P=0.49) or between moderate- or higher dose and low-dose statin groups (odds ratio: 0.84; 95% CI, 0.5-1.41; P=0.51) in the incidence of postoperative AKI . Conclusions Neither preoperative statin use nor statin dose increased the risk of AKI after OPCAB . Preoperative statin therapy is not harmful in patients receiving OPCAB .

The Role of Statins in the Management of Patients Undergoing Coronary Artery Bypass Grafting

Each year, a large number of patients undergo coronary artery bypass grafting surgery (CABG) worldwide. Accumulating evidence suggests that the preoperative administration of statins might be useful in preventing adverse events after CABG. In the present review, we discuss the role of statins in the perioperative management of patients undergoing CABG. Preoperative administration of statins in these patients substantially reduces the risk of postoperative atrial fibrillation and shortens hospital and intensive care unit (ICU) stay. Atorvastatin appears to be more effective, particularly when administered at high doses. Given these benefits and the safety of statins, their administration should be considered in patients undergoing CABG, even though the statins do not appear to affect the incidence of cardiovascular events and overall mortality perioperatively.

Effects of five preoperative cardiovascular drugs on mortality after coronary artery bypass surgery: A retrospective analysis of an observational study of 16, 192 patients

BACKGROUND

Statins reduce risk from coronary artery bypass graft (CABG) surgery, but the influence of angiotensin-converting enzyme inhibitors, alpha-2 adrenergic agonists, calcium channel blockers and beta-blockers is less clear.

OBJECTIVES

We investigated the association of each of these drugs with perioperative risk, accounting for different confounders, and evaluated the class, dose-response and long-term protective effect of statins.

DESIGN

A retrospective analysis of observational data.

SETTING

United Kingdom.

PATIENTS

Sixteen thousand one hundred and ninety-two patients who underwent CABG surgery during the period 01 January 2004 to 31 December 2013 and contributed data to Primary Care Clinical Practice Research Datalink.

EXPOSURE VARIABLES

Cardiovascular drugs.

OUTCOME MEASURE

Perioperative mortality within 30 days of surgery.

STATISTICAL ANALYSIS

Five multivariable logistic regression models and a further Cox regression model were used to account for preexisting cardiovascular and other comorbidities along with lifestyle factors such as BMI, smoking and alcohol use.

RESULTS

Exposure to statins was most prevalent (85.1% of patients), followed by beta-blockers (72.8%), angiotensin-converting enzyme inhibitors (60.5%), calcium channel blockers (42.8%) and alpha-2 adrenergic agonists (1.2%). The mortality rate was 0.8% in patients not prescribed statins and 0.4% in those on statins. Statins were associated with a statistically significant reduced perioperative mortality in all five logistic regression models with adjusted odds ratios (OR) (95% confidence interval, 95% CI) ranging from 0.26 (0.13 to 0.54) to 0.35 (0.18 to 0.67). Cox regression for perioperative mortality [adjusted hazard ratio (95% CI) 0.40 (0.20 to 0.80)] and 6-month mortality [adjusted hazard ratio (95% CI) 0.63 (0.42 to 0.92)] produced similar results. Of the statin doses tested, only simvastatin 40 mg exerted protective effects. The other cardiovascular drugs lacked consistent effects across models.

CONCLUSION

Statins appear consistently protective against perioperative mortality from CABG surgery in multiple models, an effect not shared by the other cardiovascular drugs. Further data are needed on whether statins exert class and dose-response effects.

Perioperative Statin Therapy for Patients Undergoing Coronary Artery Bypass Grafting

Coronary artery bypass grafting is associated with an intense systemic inflammatory response, which is linked to postoperative complications. Beyond lipid lowering, statins exert a constellation of beneficial actions, including an antiinflammatory role, known as pleiotropic effects. There is increasing evidence that perioperative statin therapy improves outcomes in patients undergoing coronary artery bypass grafting. Statins are underused in the coronary artery bypass grafting population, because perioperative discontinuation remains a common practice. This article provides an extensive review of the available literature on the effect of perioperative statin therapy on post–coronary artery bypass grafting outcomes and weighs the evidence for the concerns about increased incidence of statin-related adverse effects in this setting.

WITHDRAWN: Preoperative statin therapy for patients undergoing cardiac surgery

This review has been withdrawn as authors are unable to complete the updating process.

The editorial group responsible for this previously published document have withdrawn it from publication.

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.

Current and emerging treatments for hypercholesterolemia: A focus on statins and proprotein convertase subtilisin/kexin Type 9 inhibitors for perioperative clinicians

Statins are a mainstay of hyperlipidemia treatment. These drugs inhibit the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase and have beneficial effects on atherosclerosis including plaque stabilization, reduction of platelet activation, and reduction of plaque proliferation and inflammation. Statins also have a benefit beyond atherosclerotic plaque, including anticoagulation, vasodilatation, antioxidant effects, and reduction of mediators of inflammation. In the perioperative period, statins appear to contribute to improved outcomes via these mechanisms. Both vascular and nonvascular surgery patients have been shown in prospective studies to have lower risk of adverse cardiac outcomes when initiated on statins preoperatively. However, not all patients can tolerate statins; the search for novel lipid-lowering therapies led to the discovery of the proprotein convertase subtilisin/kexin Type 9 (PCSK9) inhibitors. These drugs are fully-humanized, injectable monoclonal antibodies. With lower PCSK9 activity, low-density lipoprotein cholesterol (LDL-C) receptors are more likely to be recycled to the hepatocyte surface, where they serve to clear plasma LDL-C. Evidence from several prospective studies shows that these new agents can significantly lower LDL-C levels. While PCSK9 inhibitors offer hope of effective therapy for patients with familial hyperlipidemia or intolerance of statins, several important questions remain, including the results of long term cardiovascular outcome studies. The perioperative effects of new LDL-C-lowering drugs are unknown at present but are likely to be similar to the older agents.

Statins and delirium: is there a role?

Delirium is a serious but potentially avoidable complication in critically ill patients. Various pathophysiological processes have been associated with delirium development; however, neuroinflammation hypothesis and pleiotropic effects are the reasons why HMG-CoA reductase inhibitors have been evaluated for delirium prevention. Statin therapy is associated with favorable outcomes in critically ill patients, but significant variability of results exists in patients who received these agents postoperatively. Study design methodological weaknesses, inconsistent delirium assessment, and lack of information on sedation regimens may have confounded these outcomes. Furthermore, no evidence exists on the type of statin, lipophilic or non-lipophilic, that is associated with the most benefit or when therapy with a statin should be initiated. Thus, the efficacy of HMGM-CoA reductase inhibitors on delirium prevention has not been fully established and non-pharmacological methods should remain mainstay of therapy.

Preoperative statin therapy for patients undergoing cardiac surgery

BACKGROUND

Patients referred to cardiac surgery for cardiovascular disease are at significant risk for the development of major postoperative adverse events despite significant advances in surgical techniques and perioperative care. Statins (5-hydroxy-3-methylglutaryl-co-enzyme A (HMG-CoA) reductase inhibitors) have gained a pivotal role in the primary and secondary prevention of coronary artery disease and are thought to improve perioperative outcomes in patients undergoing cardiac surgery. This review is an updated version of a review that was first published in 2012.

OBJECTIVES

To determine the effectiveness of preoperative statin therapy in patients undergoing cardiac surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11), MEDLINE (1950 to November 2013 Week 3), EMBASE (1980 to 3 December 2013 (Week 48)) and the metaRegister of Controlled Trials. Additionally, we searched ongoing trials through the National Research Register, the ClinicalTrials.gov registry and grey literature. We screened online conference indices from relevant scientific meetings (2006 to 2014) to look for eligible trials. We applied no language restrictions.

SELECTION CRITERIA

All randomised controlled trials comparing any statin treatment before cardiac surgery, for any given duration and dose, versus no preoperative statin therapy (standard of care) or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors evaluated trial quality and extracted data from titles and abstracts identified by electronic database searches according to predefined criteria. Accordingly, we retrieved full-text articles of potentially relevant studies that met the inclusion criteria to assess definitive eligibility for inclusion. We reported effect measures as odds ratios (ORs) or weighted mean differences (WMDs) with 95% confidence intervals (95% CIs).

MAIN RESULTS

We identified 17 randomised controlled studies including a total of 2138 participants undergoing on-pump or off-pump cardiac surgical procedures, and added to this review six studies with 1154 additional participants. Pooled analysis showed that statin treatment before surgery reduced the incidence of postoperative atrial fibrillation (AF) (OR 0.54, 95% CI 0.43 to 0.67; P value < 0.01; 12 studies, 1765 participants) but failed to influence short-term mortality (OR 1.80, 95% CI 0.38 to 8.54; P value = 0.46; two studies, 300 participants) or postoperative stroke (OR 0.70, 95% CI 0.14 to 3.63; P value = 0.67; two studies, 264 participants). In addition, statin therapy was associated with a shorter stay for patients on the intensive care unit (ICU) (WMD -3.19 hours, 95% CI -5.41 to -0.98; nine studies, 721 participants) and in the hospital (WMD -0.48 days, 95% CI -0.78 to -0.19; 11 studies, 1137 participants) when significant heterogeneity was observed. Results showed no reduction in myocardial infarction (OR 0.48, 95% CI 0.21 to 1.13; seven studies, 901 participants) or renal failure (OR 0.57, 95% CI 0.30 to 1.10; five studies, 467 participants) and were not affected by subgroup analysis. Trials investigating this safety endpoint reported no major or minor perioperative side effects of statins.

AUTHORS' CONCLUSIONS

Preoperative statin therapy reduces the odds of postoperative atrial fibrillation (AF) and shortens the patient's stay on the ICU and in the hospital. Statin pretreatment had no influence on perioperative mortality, stroke, myocardial infarction or renal failure, but only two of all included studies assessed mortality. As analysed studies included mainly individuals undergoing myocardial revascularisation, results cannot be extrapolated to patients undergoing other cardiac procedures such as heart valve or aortic surgery.

The effects of preoperative statins on the incidence of postoperative acute kidney injury in patients undergoing cardiac surgeries

OBJECTIVES

Recent evidence has emphasized multifunctional therapeutic effects of statins on renal protection after cardiac surgeries. We aimed to assess the effects of preoperative administration of statins on lowering the incidence of postoperative acute kidney injury in patients undergoing cardiac surgeries.

METHODS

In a retrospective study, the preoperative, intraoperative and postoperative data of 1064 consecutive patients who underwent different forms of cardiovascular surgeries were reviewed. According to whether patients had received statins preoperatively, the patients were categorized into no statin (n = 620), low-dose statin (n = 262) or high-dose statin (n = 182) administration groups.

RESULTS

No difference was seen in postoperative incidence of acute kidney injury between the three groups (11.1, 9.9 and 11.5%, respectively, P = 0.887). The multivariate logistic regression analysis showed that advanced age [odds ratio (OR) = 1.043, P < 0.001], recent myocardial infarction within 90 days of surgery (OR = 1.935, P = 0.002) and longer intubation time (OR = 1.001, P = 0.001) could predict occurrence of kidney injury after cardiac surgery. The preoperative use of angiotensin converting enzyme (ACE) inhibitor could effectively prevent occurrence of this postoperative event (OR = 0.552, P = 0.008). After adjusting for propensity score only, statin treatment, at low or high doses, was not associated with lower postoperative acute kidney injury (OR = 1.010, P = 0.971 for low dose and OR = 1.108, P = 0.745 for high dose versus no statin). After further adjustment for propensity score, statin treatment with the different dosages was not associated with acute kidney injury (OR = 0.869, P = 0.633 for low dose and OR = 1.051, P = 0.885 for high dose versus no statin).

CONCLUSIONS

Preoperative statin use may not inhibit acute kidney injury after operation.

Effect of preoperative statin therapy on postoperative acute kidney injury in patients undergoing major surgery: systemic review and meta-analysis

We aimed to examine the association between preoperative use of statins and postoperative acute kidney injury (AKI) in patients undergoing major surgery by performing a systemic review and meta-analysis. MEDLINE and EMBASE, from inception to April 2013, and the reference lists of related articles were searched for relevant studies. Trials comparing preoperative statin therapy with no preoperative statin in patients undergoing major surgery were included. Outcome measures of interest were the risk of cumulative postoperative AKI and postoperative AKI requiring renal replacement therapy (RRT). Fixed or random effect meta-analysis was performed to derive summary effect estimates. In five randomized controlled trials (RCTs) and 19 observational studies, comprising a total of 989 173 patients undergoing major surgery, 112 840 patients (11.41%) received preoperative statin therapy. The specific type, dosage, and duration of statin therapy were not available in most studies. Preoperative statin therapy was associated with a significant risk reduction for cumulative postoperative AKI (weighted summary odds ratio (OR) 0.87, 95% CI 0.79 to 0.95). The effect of risk reduction was also significant when considering postoperative AKI requiring RRT (OR 0.80, 95% CI 0.72 to 0.90). When restricting the analysis to the five RCTs, preoperative statin therapy did not show significant protective effect on postoperative AKI (OR 0.49, 95% CI 0.22 to 1.09). In patients undergoing major surgery, preoperative statin therapy could associate with a reduced risk for postoperative AKI. However, considerable heterogeneity existed among included studies. Future randomized trials were warranted for this critical clinical question.

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.

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

BACKGROUND

Acute kidney injury (AKI) is a serious complication of cardiac operations for which there remains no specific therapy. Animal data and several observational studies suggest that statins prevent AKI, but the results are not conclusive, and many studies are retrospective in nature.

METHODS

We conducted a multicenter prospective cohort study of 625 adult patients undergoing elective cardiac operations. All patients were taking statins and were grouped according to whether statins were continued or held in the 24 hours before operation. The primary outcome was AKI as defined by a doubling of serum creatinine or dialysis. The secondary outcome was the peak level of several kidney injury biomarkers. The results were adjusted for demographic and clinical factors.

RESULTS

Continuing (vs holding) a statin before operation was not associated with a lower risk of AKI, as defined by a doubling of serum creatinine or dialysis (adjusted relative risk [RR] 1.09; 95% confidence interval [CI] 0.44, 2.70). However, continuing a statin was associated with a lower risk of elevation of the following AKI biomarkers: urine interleukin-18, urine neutrophil gelatinase-associated lipocalin, urine kidney injury molecule-1, and plasma neutrophil gelatinase-associated lipocalin (adjusted RR 0.34; 95% CI 0.18, 0.62), (adjusted RR 0.41; 95% CI 0.22, 0.76), (adjusted RR 0.37; 95% CI 0.20, 0.76), (adjusted RR 0.62; 95% CI 0.39, 0.98), respectively.

CONCLUSIONS

Statins may prevent kidney injury after cardiac operations, as evidenced by lower levels of kidney injury biomarkers.

The pleiotropic effects of the hydroxy-methyl-glutaryl-CoA reductase inhibitors in renal disease

It is well known that statins exert their main effect by inhibiting cholesterol synthesis through the inhibition of the 3-hydroxy-3-methyl-glutaryl-CoA reductase enzyme. The pleiotropic effects of statins, which are independent of their inhibition of cholesterol synthesis, have explained many of the beneficial effects of these drugs in a variety of disorders such as malignancies, infection, and sepsis, as well as in cardiovascular and rheumatologic disorders. However, the role of these drugs in renal disorders remains controversial. In the present review, we examine the most recent findings involving statins and renal disease among different clinical scenarios, including chronic kidney disease, contrast-induced nephropathy, renal injury after coronary artery bypass surgery, and renal transplant patients.

Meta-analysis of patients taking statins before revascularization and aortic valve surgery

Statin intake before cardiac surgery is associated with favorable outcomes. We sought to analyze the evidence for statin pretreatment before isolated coronary artery bypass graft surgery and aortic valve replacement surgery. In this meta-analysis, we demonstrate beneficial results for the endpoints mortality, stroke, atrial fibrillation, and length of stay in hospital in 36,053 statin-pretreated coronary artery bypass graft surgery patients compared with control subjects retrieved from 32 studies, but fail to detect relevant advantages through preoperative statin therapy for 3,091 patients undergoing aortic valve replacement from four trials. Strict adherence to guidelines recommending statin treatment before CABG surgery is therefore mandatory.

Perioperative statin therapy is not associated with reduced risk of anastomotic leakage after colorectal resection

BACKGROUND

Anastomotic leakage is a serious complication of colorectal surgery. Several studies have demonstrated the beneficial pleiotropic effects of statins, and preliminary studies have suggested that perioperative statin treatment may be associated with reduced risk of anastomotic leakage.

OBJECTIVE

We aimed to investigate whether perioperative statin therapy was associated with a reduced anastomotic leakage rate after colorectal resections with primary anastomosis.

DESIGN

The study was based on prospectively collected data from the Danish Colorectal Cancer Group and electronically registered medical records holding information on perioperative statin therapy.

SETTINGS

Data were collected from the 6 major surgical centers responsible for all elective colorectal cancer surgery in the eastern part of Denmark.

PATIENTS

We collected data on 2766 patients with electronically registered medical records who underwent resection of the colon or rectum with primary anastomosis from 2006 to 2009.

MAIN OUTCOME MEASURE

The primary outcome measured was anastomotic leakage requiring surgical intervention.

RESULTS

Five hundred eighteen patients (19%) were treated with statins perioperatively. Four hundred ninety-six patients received statins both before and after surgery. Fifty-two patients (10.5%) received high-dose statin therapy. Possible risk factors for anastomotic leakage were identified via univariate regression analyses. In subsequent multivariate analysis, perioperative statin therapy was not associated with reduced anastomotic leakage rate (OR (95% CI) 1.31 (0.84-2.05), p = 0.23). We identified intraoperative blood transfusion, rectal resection (versus colonic), male sex, and tobacco usage as risk factors for anastomotic leakage in the multivariate analysis.

LIMITATIONS

This study is limited by its observational design and missing data on comorbidities and BMI.

CONCLUSION

Perioperative statin therapy was not significantly associated with reduced anastomotic leakage rate after colorectal resection with primary anastomosis.

Preoperative statin therapy is associated with lower requirement of renal replacement therapy in patients undergoing cardiac surgery: a meta-analysis of observational studies

OBJECTIVES

Acute kidney injury (AKI) following cardiac surgery is a common complication associated with serious morbidity and mortality. Activation of inflammatory cascade and vascular endothelial dysfunction plays a vital role during the perioperative period leading to AKI. Statins are known to suppress inflammation and improve endothelial dysfunction over and above the cholesterol lowering efficacy.

METHODS

Observational studies with a defined population in terms of preoperative statin therapy and no preoperative statin therapy undergoing cardiac surgery (CABG, isolated valve surgery or both) and with reported data on the incidence of acute renal failure/injury and/or mortality were identified and analysed for inclusion in the analysis. Outcomes evaluated were occurrence of postoperative acute kidney injury/failure, requirement of any postoperative renal replacement therapy and short-term all-cause mortality rate. A meta-analysis was conducted and a pooled estimate of odds ratio (OR) was calculated using the inverse variance method.

RESULTS

A total of 17 studies with a total population of 24 998 statin users and 22 082 non-statin users were included in the final analysis. PST resulted in a significantly lower incidence of renal replacement therapy in patients undergoing CABG (OR: 0.56 [0.41-0.76]) but not in isolated valve surgery (OR: 1.80 [0.73-4.44]). Also preoperative statin therapy resulted in a significantly lower postoperative mortality (0.72 [0.61-0.84]) irrespective of the type of surgery. There was no effect of preoperative statin therapy on the incidence of AKI in any of the sub-group of the patients.

CONCLUSIONS

Patients undergoing CABG might derive benefit from preoperative statin therapy in terms of reducing the need for postoperative renal replacement therapy and mortality. However, the uncertainty concerning the reno-protective efficacy of preoperative statin therapy in patients undergoing isolated valve surgery needs further investigation.

Preoperative statin therapy in cardiac surgery: a meta-analysis of 90,000 patients

The objective of this systematic literature review with meta-analysis was to determine the strength of evidence for a preoperative statin on the reduction of adverse postoperative outcomes in patients undergoing cardiac surgery. Randomized controlled (RCT) and observational trials were searched in online databases that reported about the effects of preoperative statin therapy on major adverse clinical outcomes after cardiac surgery. Analysed outcomes included early all-cause mortality, myocardial infarction, atrial fibrillation (AF), stroke and renal failure using a priori-defined criteria. Effect estimates were calculated and are given as odds ratio (OR) with 95% confidence intervals (95% CI) using fixed- or random-effect models. Literature search of all major databases retrieved 2371 studies. After screening, a total of 54 trials were identified (12 RCT, 42 observational) that reported outcomes of 91 491 cardiac surgery patients with (n = 46 614; 51%) or without (n = 44 877; 49%) preoperative statin therapy. Preoperative statin use resulted in a 0.9% absolute risk (2.6 vs 3.5%) and a 31% odds reduction for early all-cause mortality (OR 0.69; 95% CI 0.59-0.81; P < 0.0001). In addition, statin treatment before surgery was associated with a substantial reduction (P < 0.01) in the postoperative end-points AF (OR 0.71; 95% CI 0.61-0.82), new-onset AF (OR 0.68; 95% CI 0.54-0.85), stroke (OR 0.83; 95% CI 0.74-0.93), stay on intensive care unit (weighted mean difference [WMD] -0.14; 95% CI -0.23 to -0.03; P < 0.01) and in-hospital stay (WMD -0.57; 95% CI -0.76 to -0.38; P < 0.01). No statistical differences were found between groups with regard to myocardial infarction or renal failure. In conclusion, the current systematic review strengthens the evidence that preoperative statin therapy extends substantial clinical benefit to early postoperative outcomes in cardiac surgery patients.

Effect of statin use on acute kidney injury risk following coronary artery bypass grafting

Acute kidney injury (AKI) is a serious complication of cardiovascular surgery. Although some nonexperimental studies suggest that statin use may reduce postsurgical AKI, methodologic differences in study designs leave uncertainty regarding the reality or magnitude of the effect. The aim of this study was to estimate the effect of preoperative statin initiation on AKI after coronary artery bypass grafting (CABG) using an epidemiologic approach more closely simulating a randomized controlled trial in a large CABG patient population. Health care claims from large, employer-based and Medicare insurance databases for 2000 to 2010 were used. To minimize healthy user bias, patients were identified who underwent nonemergent CABG who either newly initiated a statin <20 days before surgery or were unexposed for ≥200 days before CABG. AKI was identified <15 days after CABG. Multivariate-adjusted risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using Poisson regression. Analyses were repeated using propensity score methods adjusted for clinical and health care utilization variables. A total of 17,077 CABG patients were identified. Post-CABG AKI developed in 3.4% of statin initiators and 6.2% of noninitiators. After adjustment, a protective effect of statin initiation on AKI was observed (RR 0.78, 95% CI 0.63 to 0.96). This effect differed by age, with an RR of 0.91 (95% CI 0.68 to 1.20) for patients aged ≥65 years and an RR of 0.62 (95% CI 0.45 to 0.86) for those aged <65 years, although AKI was more common in the older group (7.7% vs 4.0%). In conclusion, statin initiation immediately before CABG may modestly reduce the risk for postoperative AKI, particularly in younger CABG patients.

Preoperative statin use and postoperative acute kidney injury

BACKGROUND

Acute kidney injury is a frequent postoperative complication that confers increased mortality, morbidity, and costs. The purpose of this study was to evaluate whether preoperative statin use is associated with a decreased risk of postoperative acute kidney injury.

METHODS

We assembled a retrospective cohort of 98,939 patients who underwent a major open abdominal, cardiac, thoracic, or vascular procedure between 2000 and 2010. Statin users were pair-matched to nonusers on the basis of surgery type, baseline kidney function, days from admission until surgery, and propensity score based on demographics, comorbid conditions, and concomitant medications. Acute kidney injury was defined based on changes in serum creatinine measurements applying Acute Kidney Injury Network and Risk-Injury-Failure staging systems, and on the need for renal replacement therapy. Associations between statin use and acute kidney injury were estimated by conditional logistic regression.

RESULTS

Across various acute kidney injury definitions, statin use was consistently associated with a decreased risk: adjusted odds ratios (95% confidence intervals) varied from 0.74 (0.58-0.95) to 0.80 (0.71-0.90). Associations were similar among diabetics and nondiabetics, and across strata of baseline kidney function. The protective association of statins was most pronounced among patients undergoing vascular surgery and least among patients undergoing cardiac surgery.

CONCLUSIONS

Preoperative statin use is associated with a decreased risk of postoperative acute kidney injury. Future randomized clinical trials are needed to determine causality.

Pilot double-blind, randomized controlled trial of short-term atorvastatin for prevention of acute kidney injury after cardiac surgery

AIM

To test whether short-term perioperative administration of oral atorvastatin could reduce incidence of postoperative acute kidney injury (AKI) in cardiac surgical patients.

METHODS

We conducted a double-blind, randomized controlled trial in 100 cardiac surgical patients at increased risk of postoperative AKI. Patients were randomized to atorvastatin (40 mg once daily for 4 days starting preoperatively) or identical placebo capsule. Primary outcome was to detect a smaller absolute rise in postoperative creatinine with statin therapy. Secondary outcomes included AKI defined by the creatinine criteria of RIFLE consensus classification (RIFLE R, I or F), change in urinary neutrophil gelatinase-associated lipocalin (NGAL) concentration, requirement for renal replacement therapy, length of stay in intensive care, length of stay in hospital and hospital mortality.

RESULTS

Study groups were well matched. For each patient maximal increase in creatinine during the 5 days after surgery was assessed; median maximal increase was 28 µmol/L in the atorvastatin group and 29.5 µmol/L in the placebo group (P = 0.62). RIFLE R or greater occurred in 26% of patients with atorvastatin and 32% with placebo (P = 0.65). Postoperatively urine NGAL changes were similar (median NGAL : creatinine ratio at intensive care unit admission: atorvastatin group 1503 ng/mg, placebo group 1101 ng/mg; P = 0.22). Treatment was well tolerated and adverse events were similar between groups.

CONCLUSION

Short-term perioperative atorvastatin use was not associated with a reduced incidence of postoperative AKI or smaller increases in urinary NGAL. (ClinicalTrials.gov NCT00910221).

Preoperative statin therapy for patients undergoing cardiac surgery

BACKGROUND

Patients referred to cardiac surgery for cardiovascular disease are at significant risk for the development of post-operative major adverse events despite significant advances in surgical techniques and perioperative care. Statins (HMG-CoA reductase inhibitors) have gained a pivotal role in the primary and secondary prevention of coronary artery disease, and are thought to improve perioperative outcomes in patients undergoing cardiac surgery.

OBJECTIVES

To determine the effectiveness of a preoperative statin therapy in patients undergoing cardiac surgery.

SEARCH METHODS

We searched CENTRAL (Issue 2 of 4, 2010 on The Cochrane Library), MEDLINE (1950 to May, Week 1 2010), EMBASE (1980 to 2010 Week 19), and the metaRegister of Controlled Trials. Additionally, ongoing trials were searched through the National Research Register, the ClinicalTrials.gov registry and grey literature. Conference indices from relevant scientific meetings (2006-2009) were screened online for eligible trials. No language restrictions were applied.

SELECTION CRITERIA

All randomized controlled trials comparing any statin treatment before cardiac surgery, for any given duration and dose, to no preoperative statin therapy (standard of care) or placebo.

DATA COLLECTION AND ANALYSIS

Two authors evaluated trial quality and extracted data from titles and abstracts identified from the electronic database searches according to pre-defined criteria. Accordingly, full text articles of potentially relevant studies that met the inclusion criteria were retrieved to assess definite eligibility for inclusion. Effect measures are reported as odds ratios (OR) or weighted mean difference (WMD) with 95% confidence intervals (95%-CI).

MAIN RESULTS

Eleven randomized controlled studies including a total of 984 participants undergoing on- or off-pump cardiac surgical procedures were identified. Pooled analysis showed that statin pre-treatment before surgery reduced the incidence of post-operative atrial fibrillation (AF) (OR 0.40; 95%-CI: 0.29 to 0.55; p<0.01), but failed to influence short-term mortality (OR 0.98, 95%-CI: 0.14 to 7.10; p=0.98) or post-operative stroke (OR 0.70, 95%-CI: 0.14 to 3.63; p=0.67). In addition, statin therapy was associated with a shorter length of stay of patients on the intensive care unit (ICU) (WMD: -3.39 hours; 95%-CI: -5.77 to -1.01) and in-hospital (WMD: -0.48 days; 95%-CI: -0.85 to -0.11) where significant heterogeneity was observed. There was no reduction in myocardial infarction (OR 0.52; 95%-CI: 0.2. to 1.30) or renal failure (OR 0.41; 95%-CI: 0.15 to 1.12). These results were unaffected after subgroup analysis. No major or minor perioperative statin side-effects were reported from trials investigating this safety endpoint.

AUTHORS' CONCLUSIONS

Preoperative statin therapy reduces the odds of post-operative AF and shortens the stay on the ICU and in the hospital. Statin pretreatment had no influence on perioperative mortality, stroke, myocardial infarction or renal failure. Since analysed studies included mainly patients undergoing myocardial revascularizations the results cannot be extrapolated to patients undergoing other cardiac procedures such as heart valve or aortic surgery.

Lipid-lowering therapy and coronary artery bypass graft surgery: what are the benefits?

PURPOSE OF REVIEW

Despite their apparent benefits, statins remain underutilized after coronary artery bypass graft (CABG) surgery. To summarize the literature regarding statin therapy and CABG, we performed a systematic review of the Medline database from 1987-2011 to assess the benefits of statins in CABG patients, including the role of high-dose therapy, and highlight areas for future study.

RECENT FINDINGS

When administered prior to CABG, statins reduce the risk of perioperative mortality, stroke, and atrial fibrillation. After CABG, statins limit the progression of atherosclerosis in native coronary arteries, inhibit the process of saphenous vein graft disease, and improve vein graft patency. Furthermore, postoperative statins reduce the recurrence of cardiovascular events and improve all-cause mortality. High-intensity statin therapy early after surgery may benefit CABG patients, but this is yet to be evaluated prospectively.

SUMMARY

Statins clearly improve the outcomes of CABG patients. In the absence of contraindications, all patients undergoing CABG are candidates for life-long statin therapy, with initiation recommended as soon as coronary disease is documented. Statins should be restarted early after surgery. However, the optimal postoperative lipid-lowering regimen remains unknown and should be the subject of upcoming trials. Strategies directed toward improving statin prescription rates and patient adherence should also be priorities for future research.

Integrating outcome benefit into anesthetic design: the promise of steroids and statins

Steroids and statins may facilitate the integration of anesthetic design with clinical outcome. Although steroids clearly benefit adult cardiac surgical patents, the evidence is weaker in pediatric cardiac surgery. Current large randomized trials of steroids likely will determine the future role of steroids in adult cardiac surgery. In the intensive care unit, steroid therapy is indicated in septic shock that is refractory to fluid and pressor therapy. Recent data, however, indicate that liberal steroid therapy for sepsis may have adverse outcome consequences. A 2nd concern in the intensive care unit is acute adrenal suppression secondary to bolus etomidate therapy because it may be deleterious in patients with septic shock. Possible clinical solutions include alternative induction agents, concomitant steroid therapy, and recent etomidate derivatives. Statins also reduce mortality and atrial fibrillation after cardiac surgery. Furthermore, they slow the progression of rheumatic valvular stenosis, an important consideration in the developing world. Statins also may reduce delirium, stroke, and acute renal injury after cardiac surgery, but further randomized trials are required before definitive recommendations can be formulated. Statins are essential in vascular surgery because they reduce mortality, myocardial ischemia, and acute renal injury. As a result, they have been recommended highly for outcome enhancement in recent perioperative guidelines. Although they may improve survival in sepsis, further investigation is indicated to define their therapeutic role.

Statin use associates with a lower incidence of acute kidney injury after major elective surgery

Statins abrogate ischemic renal injury in animal studies but whether they are renoprotective in humans is unknown. We conducted a population-based retrospective cohort study that included 213,347 older patients who underwent major elective surgery in the province of Ontario, Canada from 1995 to 2008. During the first 14 postoperative days, 1.9% (4020 patients), developed acute kidney injury and 0.5% (1173 patients), required acute dialysis. The 30-day mortality rate was 2.8% (5974 patients). Prior to surgery, 32% of patients were taking a statin. After statistical adjustment for patient and surgical characteristics, statin use associated with 16% lower odds of acute kidney injury (OR, 0.84; 95% CI, 0.79 to 0.90), 17% lower odds of acute dialysis (OR, 0.83; 95% CI, 0.72 to 0.95), and 21% lower odds of mortality (OR, 0.79; 95% CI, 0.74 to 0.85). Propensity score matching produced similar results. These data suggest that statins may protect against renal complications after major elective surgery and reduce perioperative mortality.

Preoperative Statins and Acute Kidney Injury After Cardiac Surgery: Utilization of a Consensus Definition of Acute Kidney Injury

Background

Previous trials investigating preoperative statin use for prevention of acute kidney injury following cardiovascular surgery were limited to patients undergoing a specific procedure and many used nonconsensus definitions of acute kidney injury.

Objective

To use a consensus definition of acute kidney injury for evaluating the association of preoperative statin use with the development of acute kidney injury following cardiac surgery utilizing cardiopulmonary bypass.

Methods

We retrospectively evaluated a cohort of 667 patients ≥18 years who underwent any cardiac surgery on cardiopulmonary bypass between April 2007 and May 2009 at Mercy Hospital in Scranton, PA. Patients were excluded if they were receiving preoperative renal replacement therapy, had stage 5 chronic kidney disease, or did not have a postoperative serum creatinine level assessed. The primary outcome was the odds of developing acute kidney injury given the use of preoperative statins. Acute kidney injury was defined based on the Acute Kidney Injury Network criteria as either an absolute increase in serum creatinine of ≥0.3 mg/dL or 1.5 times baseline, or the need for postoperative renal replacement therapy.

Results:

The final analysis included 563 patients; 356 were receiving preoperative statins. The incidence of acute kidney injury was 35.1% in the statin group and 26.1% in the non-statin group. On univariate analysis statins were associated with an increase in the odds of acute kidney injury (OR 1.53; 95% CI 1.05 to 2.24). Multivariate logistic regression did not demonstrate an association of statins with acute kidney injury (OR 1.36; 95% CI 0.904 to 2.05). Repeating the analysis using 312 propensity score–matched patients also showed no association of statins with acute kidney injury (OR 1.17; 95% CI 0.715 to 1.93).

Conclusions:

Our findings do not support the hypothesis that preoperative statin use is associated with a decrease in the incidence of acute kidney injury following cardiac surgery utilizing cardiopulmonary bypass.

Progress in perioperative medicine: focus on statins

Beyond cholesterol reduction, statins have multiple beneficial influences on vascular endothelial function, atherosclerotic plaque stability, inflammation, and thrombosis. These favorable pleiotropic effects may be the basis for their perioperative risk reduction in cardiothoracic and vascular procedures. The published evidence suggests that statins offer significant outcome benefits throughout perioperative practice. Because statin therapy significantly reduces the perioperative risk for patients undergoing cardiovascular procedures, they already are recommended in published guidelines. Beyond cardiac risk reduction, statin therapy also may protect the brain and the kidney in the perioperative setting, both in cardiac and vascular surgery. The pleiotropic effects of statins also appear to have therapeutic roles in the progression of valve disease, sepsis, and venous thrombosis. Further trials are required to provide data to drive their safe and comprehensive perioperative application for optimal patient outcome both in the short term and the long term. Because there are multiple randomized trials currently in progress throughout perioperative medicine, it is very likely that the indications for statins will be expanded significantly.

Renal injury is associated with operative mortality after cardiac surgery for women and men

OBJECTIVES

The purpose of this study was to determine whether acute renal injury develops more frequently in women than in men after cardiac surgery and whether this complication is associated with operative mortality in women.

METHODS

Prospectively collected data were evaluated from 9461 patients undergoing coronary artery bypass graft surgery, cardiac valve surgery, or both (3080 women) and not receiving preoperative dialysis. The glomerular filtration rate was estimated by using the Modification of Diet in Renal Disease equations with the last plasma creatinine level before surgical intervention (baseline) and the highest level of the first postoperative week. The primary renal injury outcome was the composite end point of renal injury according to RIFLE criteria (estimated glomerular filtration rate decrease >50% from baseline value) or failure.

RESULTS

Thirty-day operative mortality and renal injury were more common in women than in men (5.9% vs 2.8%, P = .01; 5.1% vs 3.6%, P < .001, respectively). Nonetheless, patient sex was not independently associated with risk for renal injury when the baseline estimated glomerular filtration rate was included in multivariate modeling. Perioperative complications, intensive care unit length of stay, and mortality were more frequent for patients with than without renal injury (women, 20.6% vs 3.2%, P < .0001; men, 18.3% vs 2.2%, P < .001). Renal injury was independently associated with 30-day mortality for women (odds ratio, 3.96; 95% confidence interval, 1.86-8.44; P < .0001) and men (odds ratio, 4.05; 95% confidence interval, 2.19-7.48; P < .0001).

CONCLUSIONS

Postoperative renal injury is independently associated with 30-day mortality regardless of patient sex. Higher rates of renal injury in women compared with men might be explained in part by a higher prevalence of low estimated glomerular filtration rate before surgical intervention.

Preoperative statin therapy is not associated with a reduced incidence of postoperative acute kidney injury after cardiac surgery

BACKGROUND

Our objective was to examine the association between preoperative statin therapy and the prevalence of postoperative acute kidney injury (AKI) in patients undergoing cardiac surgery with the use of cardiopulmonary bypass.

METHODS

We performed a retrospective investigation of 10,648 consecutive patients undergoing coronary artery bypass grafting using cardiopulmonary bypass and/or valve surgery between January 2002 and December 2006. Patients were divided into 2 groups depending on preoperative therapy with statin drugs. The primary outcome was postoperative AKI based on the RIFLE (Risk, Injury, Failure, Loss, End-stage) criteria. Secondary outcomes included requirement for postoperative dialysis and hospital mortality. Multivariable logistic regression models were developed for the primary and secondary outcomes. To control for selection bias related to statin therapy, a propensity score was developed using a greedy matching technique.

RESULTS

The incidence of AKI was 12.1% (n = 1286). AKI occurred in 13.31% of patients receiving preoperative statins (819 of 6152 patients) versus 10.41% in the no statin group (467 of 4487 patients) (P < 0.001). The incidence of postoperative dialysis was 1.71% (n = 182). Postoperative dialysis was needed in 1.75% of patients in the statin group (108 of 6157 patients) compared with 1.65% of patients (74 of 4491 patients) in the no statin group (P = 0.68). Hospital mortality after surgery occurred in 1.71% (n = 182) of patients. The incidence of mortality for patients in the statin group was 1.71% (105 of 6157 patients) and this was not different from mortality in the no statin group of 1.71% (77 of 4491 patients) (P = 0.97). In multivariate logistic regression analysis, statin therapy was not associated with AKI (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.84-1.12; P = 0.68), postoperative dialysis (OR 0.80, 95% CI 0.55-118; P = 0.23), or hospital mortality (OR 0.803, 95% CI 0.56-1.16; P = 0.24). In 2646 propensity-matched pairs, the incidence of AKI was 12.0% in the statin group versus 12.8% in the no statin group (P = 0.38). The statin group had a 1.63% incidence of postoperative dialysis versus 2.08% in the no statin group (P = 0.22). In the same propensity-matched population, hospital mortality occurred in 1.63% of patients in the statin group compared with 2.1% in the no statin group (P = 0.19).

CONCLUSION

These results suggest that previously reported reductions in perioperative mortality for patients taking preoperative statins and undergoing cardiac surgery is likely not mediated through a reduction in postoperative AKI.

Acute kidney injury in the elderly: pathogenesis, diagnosis and therapy

Elderly patients, especially those with chronic kidney disease, are at least a 3.5-fold higher risk for the development of acute kidney injury (AKI). With aging, renal functional reserve is lower owing to specific cellular changes that affect function. Molecular studies are elucidating these cellular changes and offer the prospect of designing novel therapeutics. The spectrum of AKI in elderly patients is wide but is over-represented by prerenal and postrenal (obstructive) etiologies. This reflects potentially nephrotoxic clinical variables, such as combordid states, impaired baseline renal function, polypharmacy and an increase in high-risk procedures. In this population, the development of AKI can lead to longer hospital stays, higher mortality rates and an increased risk for the development of chronic kidney disease and end-stage renal disease. Careful attention to clinical risk factors, avoidance of nephrotoxic insults and meticulous supportive care for patients who develop AKI is critical in alleviating the burden of this problem.