Preoperative statin therapy decreases risk of postoperative renal insufficiency

Effect of preoperative moderate-dose statin and duration on acute kidney injury after cardiac surgery: a retrospective cohort study

BACKGROUND

The impact of preoperative statin use on postoperative acute kidney injury (AKI) is uncertain. We aimed to examine the association of statin therapy before cardiac surgery with postoperative AKI.

METHODS

The retrospective cohort study consisted of 1581 patients undergoing cardiac surgery. Postoperative AKI were identified by the modified KDIGO definition. Propensity-score matching was employed to control for selection bias, and logistic regression was used to control for confounders. Subgroup and interaction analyses were performed to evaluate the robustness of the findings.

RESULTS

The overall incidence of postoperative AKI and severe AKI were 42.19% and 12.27%, respectively. Preoperative moderate-dose statin was significantly associated with a reduced incidence of postoperative AKI (28.9% vs 43.0%, OR (95%CI): 0.54 (0.38, 0.77), p < 0.001) and severe AKI (6.9% vs 13.7%, OR (95%CI): 0.46 (0.26, 0.83), p = 0.009). The beneficial effect on postoperative AKI persisted after adjusting for major confounding factors (OR (95%CI): 0.47 (0.34, 0.66)). Decreased risk of postoperative AKI was observed in patients with preoperative statin duration of 7 ∼ 14 days (OR (95%CI): 0.41 (0.25, 0.65)) and over 14 days (OR (95%CI): 0.43 (0.28, 0.65)), but not in those with preoperative statin duration of <7 days. Similar favorable effects were noted in most subgroup patients, except for those with high-risk factors such as diabetes mellitus, previous congestive cardiac failure, arrhythmia, preoperative ACEI/ARB, aortic cross-clamping or IABP.

CONCLUSION

Preoperative moderate-dose statin was significantly related to a decreased risk of postoperative AKI, especially in patients who received statins for a longer duration. Further large-scale multicenter randomized controlled trials are needed to ascertain the impact of statin dose, duration, and timing on postoperative AKI in cardiac surgery patients.

The effect of preoperative statins on postoperative mortality, renal, and neurological complications in patients undergoing cardiac surgeries: a retrospective cohort study

BACKGROUND

Cardiac surgery is performed worldwide to treat severe cases of cardiovascular diseases. Statins have shown controversial effects on complications after cardiac surgeries. We aimed to investigate the effect of preoperative statin therapy on the frequency of postoperative mortality, renal, and neurological complications.

METHODS

In a retrospective cohort study, the database of patients operated on in two hospitals in southern Iran during 2008-2019 was used to compare preoperative statin use with no use on the composite outcome of mortality, renal, and neurological complications as well as on each component of the composite, separately. Effects of low dose (<40 mg simvastatin equivalence) vs. high dose (≥40 mg) statins were also evaluated. Confounders that could affect the outcomes were considered in the logistic regression model, and multiple imputation techniques were used to categorize patients with unknown statin dose use as either high or low-dose users.

RESULTS

Of total 7329 patients, 17.6% of statin users and 17% of non-statin users developed the composite outcome (P=0.51). Statin use had no statistically significant association with the composite outcome (aRR 1.01 [95% CI: 0.88-1.16]). There was no significant association with mortality [aRR: 0.75 (95% CI: 0.34-1.69)], neurological [aRR: 1.25 (95% CI: 0.77-2.12)], or renal complications [aRR: 1.03 (95% CI 0.90-1.19)] after surgery. Neither low nor high doses had any statistically significant effect on the composite or any of its components.

CONCLUSIONS

In this large study, preoperative statin use, either high dose or low dose, did not affect short-term postoperative mortality, neurological, or renal complications.

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.

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 .

Do Statins Induce or Protect from Acute Kidney Injury and Chronic Kidney Disease: An Update Review in 2018

Statins essentially are cholesterol-lowering drugs that are extensively prescribed for primary and secondary prevention of cardiovascular disease. Compelling evidence suggests that the beneficial effects of statins may not only be due to its ability to control cholesterol levels but also due to a pleiotropic cholesterol-independent anti-inflammatory, antioxidant, endothelial-protective and plaque-stabilizing activity. Along this line, statins may also exert acute and long-term effects on renal function. We present a narrative literature review that summarizes arguments in favor of or against the preventive and/or therapeutic use of statins in kidney-related diseases or complications. We also highlight the ongoing controversy regarding statin therapy in chronic and end-stage kidney disease.

Is there evidence for statins in the treatment of aortic valve stenosis?

Research revealed that the pathogenesis of aortic stenosis (AS) not merely comprises of a mechanical wear and tear process yet that active biological processes, similar to those of coronary artery disease are involved, a promising role for statins in disease-modifying therapy was suggested. However, recently, many prospective studies could not observe decreased progression nor regression of the disease. Here, we review the current knowledge on the pathomechanisms of AS and its similarities and differences with atherosclerosis. Moreover, we discuss whether there is still a place for statins in the treatment of particular AS patient subgroups.

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.

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.

Shock Management for Cardio-surgical Intensive Care Unit Patient: The Silver Days

Shock in cardio-surgical intensive care unit (ICU) patients requires prompt identification of the underlying condition and timely therapeutic interventions. Management during the first 6 hours, also referred to as "the golden hours", is of paramount importance to reverse the shock state and improve the patient's outcome. The authors have previously described a state-of-the-art diagnostic work-up and discussed how to optimise preload, vascular tone, contractility, heart rate and oxygen delivery during this phase. Ideally, shock can be reversed during this initial period. However, some patients might have developed multiple organ dysfunction, which persists beyond the first 6 hours despite the early haemodynamic treatment goals having been accomplished. This period, also referred to as "the silver days", is the focus of this review. The authors discuss how to reduce vasopressor load and how to minimise adrenergic stress by using alternative inotropes, extracorporeal life-support and short acting beta-blockers. The review incorporates data on fluid weaning, safe ventilation, daily interruption of sedation, delirium management and early rehabilitation. It includes practical recommendations in areas where the evidence is scarce or controversial. Although the focus is on cardio-surgery ICU patients, most of the considerations apply to critical ill patients in general.

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.

Association between preoperative diuretic use and in-hospital outcomes after cardiac surgery

BACKGROUND

There is a paucity of evidence on the association between preoperative diuretics use and outcomes following cardiac surgery. We hypothesized that diuretic use prior to cardiac surgery will be associated with adverse in-hospital clinical outcomes.

METHODS

We evaluated patients undergoing cardiac surgery at a single institution between January 1, 2000, and December 31, 2011. Patients were grouped as follows: isolated coronary artery bypass grafting (CABG) (n = 8759), CABG plus valve surgery (n = 1188), and valve surgery only (n = 2646). A fourth group "All cardiac surgery" is comprised of patients from all three groups. Preoperative diuretic use was defined as patient on any diuretic till the day of surgery. Primary outcome was the incidence of major adverse events (MAEs) defined as the composite of mortality, postoperative renal dysfunction, myocardial infarction, stroke, and new-onset atrial fibrillation (AF). Logistic regression analysis and propensity score matching were performed.

RESULTS

We included 12,593 patients [3546 on diuretic (28%)]. After logistic regression analyses, preoperative diuretic use was associated with an increased risk of the following: (1) MAE among all groups except the concomitant CABG and valve surgery group, (2) AF in "All cardiac surgery" and isolated CABG groups, (3) postoperative renal dysfunction in all groups. After propensity score matching (n = 3050 in each group), preoperative diuretic use was significantly associated with MAE (48% vs. 43%; P < 0.0001), postoperative renal dysfunction (19% vs. 14%; P < 0.0001), and AF (34% vs. 32%; P = 0.03) in the "All cardiac surgery" group.

CONCLUSION

Preoperative diuretics use is associated with an increased incidence of MAEs after cardiac surgery.

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.

Single nucleotide polymorphisms in cholesteryl ester transfer protein gene and recurrent coronary heart disease or mortality in patients with established atherosclerosis

It is not known whether genetic variants in the cholesteryl ester transfer protein (CETP) gene are associated with recurrent coronary heart disease events or mortality in secondary prevention patients. Among 3,717 patients with acute coronary syndrome or coronary artery bypass grafting (CABG) enrolled in a prospective genetic registry, we evaluated whether CETP gene variants previously shown to be associated with reduced CETP activity and high-density lipoprotein cholesterol increase ("A" allele for both TaqIB [rs708272] and rs12149545) are associated with a reduction in recurrent myocardial infarction (MI), recurrent revascularization, or death. At 4.5 years of follow-up, 439 recurrent MI, 698 recurrent revascularizations, and 756 deaths occurred. Using an additive model of inheritance, the "A" allele for rs708272 was not associated with recurrent MI (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.78 to 1.17 for AG; HR 0.89, 95% CI 0.67 to 1.19 for AA; compared with GG genotype), recurrent revascularization (HR 1.13, 95% CI 0.95 to 1.33 for AG; HR 1.05, 95% CI 0.84 to 1.32 for AA), or mortality (HR 1.02, 95% CI 0.86 to 1.19 for AG; HR 1.11, 95% CI 0.91 to 1.37 for AA) in the overall cohort. Similar results were seen for the "A" allele for rs12149545. In the CABG subgroup, AG genotype for rs708272 was associated with an increased mortality (HR 1.38, 95% CI 1.06 to 1.79) compared with GG genotype. Results remained consistent using dominant model of inheritance. In conclusion, genetic CETP variants were not associated with recurrent MI or recurrent revascularization in overall cohort with a possible mortality increase in patients who underwent CABG.

Preoperative angiotensin-converting enzyme inhibitors and angiotensin receptor blocker use and acute kidney injury in patients undergoing cardiac surgery

BACKGROUND

Using either an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin receptor blocker (ARB) the morning of surgery may lead to 'functional' postoperative acute kidney injury (AKI), measured by an abrupt increase in serum creatinine. Whether the same is true for 'structural' AKI, measured with new urinary biomarkers, is unknown.

METHODS

The TRIBE-AKI study was a prospective cohort study of 1594 adults undergoing cardiac surgery at six hospitals between July 2007 and December 2010. We classified the degree of exposure to ACEi/ARB into three categories: 'none' (no exposure prior to surgery), 'held' (on chronic ACEi/ARB but held on the morning of surgery) or 'continued' (on chronic ACEi/ARB and taken the morning of surgery). The co-primary outcomes were 'functional' AKI based upon changes in pre- to postoperative serum creatinine, and 'structural AKI', based upon peak postoperative levels of four urinary biomarkers of kidney injury.

RESULTS

Across the three levels (none, held and continued) of ACEi/ARB exposure there was a graded increase in functional AKI, as defined by AKI stage 1 or worse; (31, 34 and 42%, P for trend 0.03) and by percentage change in serum creatinine from pre- to postoperative (25, 26 and 30%, P for trend 0.03). In contrast, there were no differences in structural AKI across the strata of ACEi/ARB exposure, as assessed by four structural AKI biomarkers (neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, interleukin-18 or liver-fatty acid-binding protein).

CONCLUSIONS

Preoperative ACEi/ARB usage was associated with functional but not structural acute kidney injury. As AKI from ACEi/ARB in this setting is unclear, interventional studies testing different strategies of perioperative ACEi/ARB use are warranted.

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.

Perioperative acute kidney injury

The incidence of acute kidney injury (AKI) is generally 5-7.5% in all acute care hospitalizations and accounts for up to 20% of admissions to intensive care units (ICUs). Of all of the cases of AKI during hospitalization, approximately 30-40% are observed in operative settings. AKI is a serious morbidity that is associated with greater length of hospital stay, high risk of hospital mortality, and increased risk of incident and progressive chronic kidney disease. The incidence of AKI is variable depending on the specific surgical setting under consideration. Much of our knowledge regarding the epidemiology of AKI is derived from studies related to cardiac or vascular surgery. With limited treatment options, prevention of AKI and amelioration of its severity remain important cornerstones of improving patient outcomes. The magnitude of the problem and the unique set of patient characteristics calls for a multidisciplinary approach for the perioperative management of renal complications. The purpose of the review presented here is to discuss the current knowledge regarding the epidemiology and risk factors, outcomes, diagnoses, and prevention and treatment of AKI during the perioperative period in cardiovascular and noncardiovascular surgical settings.

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.

Association between statins and infections after coronary artery bypass grafting

BACKGROUND

We determined whether pre-operative statin therapy is associated with a decrease in the incidence of infections after coronary artery bypass grafting (CABG).

METHODS

A retrospective cohort study of 6253 patients undergoing isolated CABG, from the Texas Heart Institute Database from January 1, 2000 to December 31, 2010 (3869 receiving statins and 2384 not receiving statins) was conducted. Primary outcome was the development of any postoperative infection (composite of deep-sternal wound infection, leg harvest-site infection, pneumonia, or sepsis) after CABG. Secondary outcome was the association between pre-operative statin use and individual incidence of each aforementioned infection. Logistic regression analyses were performed.

RESULTS

Incidence of any postoperative infection in patients who received statins pre-operatively was 6.5% compared to 8.3% in patients who did not receive statins. Pre-operative statin therapy was associated with a significant reduction in the primary outcome (odds ratio (OR) 0.74, 95% confidence interval (CI) 0.60-0.90) in adjusted models. Among individual secondary outcomes, pre-operative statin therapy was associated with a reduced incidence of sternal wound infections (2.5% vs. 3.2%, OR 0.6, 95% CI 0.5-0.8) and leg harvest site infections (0.6% vs. 1.3%, OR 0.46, 95% CI 0.2-0.8). Pre-operative statin therapy was not associated with a reduced incidence of pneumonia or sepsis.

CONCLUSION

Pre-operative statin use is associated with a decrease in overall incidence of post-operative infections after CABG. We propose immunomodulatory effects of statins leading to a dampening of inflammatory cascade as the cause of our findings.

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).

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.

Statins--is there potential for uncovering new benefits (or detriments)?

Despite over 20 years of clinical use and 15 years of clinical trial data, we still do not have a complete understanding of the mechanisms of action or full utility of statins as a class of drugs. The possibility of their use as a treatment for prevention of peri-operative morbidity and mortality is one of the newest indications being explored for this class of drugs. Issues regarding drug dosing and timing may rely on being able to elucidate and separate potential pleiotropic actions from lipid-lowering actions to identify the optimal benefit of these drugs in the peri-operative setting. Careful consideration of these two actions need to be considered in the design of adequately powered clinical trials to test the potential utility and safety of using statins in the peri-operative setting.