The pharmaco-economics of peri-operative statin therapy

Perioperative statin therapy for improving outcomes during and after noncardiac vascular surgery

BACKGROUND

Patients undergoing vascular surgery are a high-risk population with widespread atherosclerosis, an adverse cardiovascular risk profile and often multiple co-morbidities. Postoperative cardiovascular complications, including myocardial infarct (MI), are common. Statins are the medical treatment of choice to reduce high cholesterol levels. Evidence is accumulating that patients taking statins at the time of surgery are protected against a range of perioperative complications, but the specific benefits for patients undergoing noncardiac vascular surgery are not clear.

OBJECTIVES

We examined whether short-term statin therapy, commenced before or on the day of noncardiac vascular surgery and continuing for at least 48 hours afterwards, improves patient outcomes including the risk of complications, pain, quality of life and length of hospital stay. We also examined whether the effect of statin therapy on these outcomes changes depending on the dose of statin received.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 7), MEDLINE via Ovid SP (1966 to August 2012), EMBASE via Ovid SP (1966 to August 2012), CINAHL via EBSCO host (1966 to August 2012) and ISI Web of Science (1946 to July 2012) without any language restriction. We used a combination of free text search and controlled vocabulary search. The results were limited to randomized controlled clinical trials (RCTs). We conducted forwards and backwards citation of key articles and searched two clinical trial Websites for ongoing trials (www.clinicaltrials.gov and http://www.controlled-trials.com).

SELECTION CRITERIA

We included RCTs that had compared short-term statin therapy, either commenced de novo or with existing users randomly assigned to different dosages, in adult participants undergoing elective and emergency noncardiac arterial surgery, including both open and endovascular procedures. We defined short-term as commencing before or on the day of surgery and continuing for at least 48 hours afterwards.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data, including information on adverse events. We contacted study authors for additional information. We performed separate analyses for the comparisons of statin with placebo/no treatment and between different doses of statin. We presented results as pooled risk ratios (RRs) with 95% confidence intervals (CIs) based on random-effects models (inverse variance method). We employed the Chi(2) test and calculated the I(2) statistic to investigate study heterogeneity.

MAIN RESULTS

We identified six eligible studies in total. The six Included studies were generally of high quality, but the largest eligible study was excluded because of concerns about its validity. Study populations were statin naive, which led to a considerable loss of eligible participants.Five RCTs compared statin use with placebo or standard care. We pooled results from three studies, with a total of 178 participants, for mortality and non-fatal event outcomes. In the statin group, 7/105 (6.7%) participants died within 30 days of surgery, as did 10/73 (13.7%) participants in the control group. Only one death in each group was from cardiovascular causes, with an incidence of 0.95% in statin participants and 1.4% in control participants, respectively. All deaths occurred in a single study population, and so effect estimates were derived from one study only. The risk ratio (RR) of all-cause mortality in statin users showed a non-significant decrease in risk (RR 0.73, 95% CI 0.31 to 1.75). For cardiovascular death, the risk ratio was 1.05 (95% CI 0.07 to 16.20). Non-fatal MI within 30 days of surgery was reported in three studies and occurred in 4/105 (3.8%) participants in the statin group and 8/73 (11.0%) participants receiving placebo, for a non-significant decrease in risk (RR 0.47, 95% CI 0.15 to 1.52). Several studies reported muscle enzyme levels as safety measures, but only three (with a total of 188 participants) reported explicitly on clinical muscle syndromes, with seven events reported and no significant difference found between statin users and controls (RR 0.94, 95% CI 0.24 to 3.63). The only participant-reported outcome was nausea in one small study,with no significant difference in risk between groups.Two studies compared different doses of atorvastatin, with a total of 145 participants, but reported data were not sufficient to allow us to determine the effect of higher doses on any outcome.

AUTHORS' CONCLUSIONS

Evidence was insufficient to allow review authors to conclude that statin use resulted in either a reduction or an increase in any of the outcomes examined. The existing body of evidence leaves questions about the benefits of perioperative use of statins for vascular surgery unanswered. Widespread use of statins in the target population means that it may now be difficult for researchers to undertake the large RCTs needed to demonstrate any effect on the incidence of postoperative cardiovascular events. However, participant-reported outcomes have been neglected and warrant further study.

Perioperative cardioprotection

Although anaesthesia itself is now very safe, perioperative cardiac complications during non-cardiovascular surgery are a major cause of morbidity and mortality, because of the increasingly high underlying prevalence of cardiovascular disease. Fortunately, although there is no "magic bullet", pharmacological intervention can reduce the risk. In particular, current evidence strongly supports the use of aspirin and statins. Beta blockers may also be beneficial in higher risk groups but need to be titrated to effect, and their use requires careful consideration because of adverse effects in these patients.

Novel uses for statins in surgical patients

BACKGROUND

Aside from their cholesterol-lowering effects statins are known to have a range of other 'pleiotropic' effects. We present an overview of the basic science behind these effects and then review clinical trials and the current role of statins relevant to modern surgical practice.

METHODS

A systematic review of the literature was performed using the keywords surgery and the MeSH term for statins. All clinical studies relating to statin use in surgical patients were evaluated. An overview of the literature on statin use and cardiac outcomes was performed.

CONCLUSIONS

Statins are safe and have a wide range of pleiotropic effects relevant to surgical practice. Strongest evidence for their clinical use comes in primary cardiac risk reduction in many types of vascular surgery. There is a large body of evidence showing their benefit perioperatively in high-risk vascular and cardiac surgery but the picture is less clear for low-risk patients. Further studies are needed to evaluate exact dosage regimes and timing of administration. Novel uses of their anti-inflammatory properties in sepsis and vasomotor properties in subarachnoid haemorrhage are being further investigated by randomised trials.

A peri-operative statin update for non-cardiac surgery. Part II: Statin therapy for vascular surgery and peri-operative statin trial design

This is the second of two review articles evaluating peri-operative statin therapy. In surgical patients, the utility of peri-operative statin therapy is strongly suggested by retrospective studies, although it is probably overestimated, as important confounding factors have not been controlled for and hence the literature is considered to be currently inconclusive. This review examines the potential mechanisms and indications for peri-operative statin protection, the efficacy of acute peri-operative beta-blockade in addition to statin therapy, the effect of peri-operative statin therapy withdrawal and the implications of comorbidities associated with peri-operative cardiovascular risk on statin therapy. Recommendations concerning appropriate dosing, duration, therapeutic targets and necessary investigations when prescribing peri-operative statins are made. Peri-operative study design recommendations are suggested, so that future meta-analyses may be more informative. Recommendations are made regarding retrospective reporting of statin studies to minimise the bias inherent in a number of the current retrospective studies on this subject.

Perioperative use of statins in noncardiac surgery

BACKGROUND

Statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) can significantly decrease cardiovascular mortality and morbidity, irrespective of the patients' cholesterol status. This paper reviews the effects of perioperative statin therapy in patients undergoing noncardiac surgery.

METHOD

A systematic literature review was undertaken of all published literature on this subject using Medline and cross-referenced. All published relevant papers on the perioperative use of statins were used.

RESULTS

Perioperative statin therapy is associated with a lower perioperative morbidity and mortality in patients undergoing elective or emergency surgery. The effects are due to a combination of lipid-lowering and pleiotropic properties of statins.

CONCLUSION

Ideally a large scale multi-centre randomized controlled trial of perioperative statin therapy should be performed but this may be difficult to conduct since there is already overwhelming evidence in the literature to suggest perioperative cardiovascular protective properties. Statins may still be under-prescribed in surgical patients.

The impact of age on 6-month survival in patients with cardiovascular risk factors undergoing elective non-cardiac surgery

An increasing number of patients aged>or=70 years are presenting for elective non-cardiac surgery. We undertook this study to: (i) compare the nature and distribution of cardiovascular disease (CVD) risk factors in an at risk population of patients aged>or=70 years undergoing elective surgery compared with a younger at risk cohort; and (ii) identify the impact of age and other risk factors on 6-month survival. We conducted a prospective observational study of patients undergoing elective non-cardiac surgery. A total of 1622 patients aged>or=40 years with recognised surgical or patient-specific risk factors for CVD were identified. The patients were divided into two groups; group 1 (aged: 40-69 years) and group 2 (aged>or=70 years). Logistic regression was used to identify the factors associated with 6-month mortality. Odds ratios (OR) and 95% confidence interval (CI) are presented. In hospital, mortality was similar in both groups. However, 6-month mortality in those aged>or=70 years was significantly higher (p=0.001). Cardiovascular symptoms were significantly more common in group 2 (p<0.001) as were cardiovascular-related deaths (p=0.04) at 6 months follow-up. Preoperative cardiovascular preventative therapy was under prescribed in the elderly cohort. Factors independently associated with 6-month mortality were aged>or=70 (OR=3.57, 95% CI: 2.22-5.73), angina (OR=2.0, 95% CI: 1.26-3.20), renal impairment (OR=2.39, 95% CI: 1.17-4.89) also operation type and duration. Despite similar in-hospital mortality, those aged>or=70 years had significantly higher 6-month mortality than the younger surgical cohort. Cardiovascular deaths were significantly higher in patients aged>or=70 years. Effective identification and the management of cardiovascular risk factors may improve 6-month survival.

Perioperative Kardioprotektion

Myocardial ischemia is a major cause of perioperative morbidity and mortality. Because of a growing expectancy of lives, the prevalence of cardiovascular diseases is increasing, and thus the number of surgical patients presenting with a cardiovascular risk profile. Based upon pathophysiological considerations, different interventions to lower perioperative cardiovascular risk have been evaluated. The mostly discussed intervention believed to prevent cardiovascular complications in the perioperative period is the use of beta-blockers. Although many authors agree that perioperative beta-blockade is effective in high-risk patients, less is known about the optimal timing, dosage and the identification of patients in whom the intervention would be beneficial. Based upon the available data we try to answer questions about timing and dosage, and we discuss possible side effects and economic questions. Another cardioprotective option is the use of statins. Besides their lipid-lowering properties, so called pleiotropic effects are believed to decrease cardiac risk. Furthermore, different interventions can be used in addition to or as an alternative to perioperative beta-blocker therapy, such as alpha-2 agonists, thoracic epidural analgesia or coronary revascularization.

Strength of evidence for perioperative use of statins to reduce cardiovascular risk: systematic review of controlled studies

OBJECTIVE

To determine the strength of evidence underlying recommendations for use of statins during the perioperative period to reduce the risk of cardiovascular events.

DESIGN

Systematic review of studies with concurrent control groups.

DATA SOURCES

Four electronic databases, the references of identified studies, international experts on perioperative medicine, and the authors of the primary studies. Review methods Two reviewers independently extracted data from studies that reported acute coronary syndromes or mortality in patients receiving or not receiving statins during the perioperative period.

MAIN OUTCOME MEASURE

Random effects summary odds ratios for death or acute coronary syndrome during the perioperative period.

RESULTS

18 studies--two randomised trials (n=177), 15 cohort studies (n=799,632), and one case-control study (n=480)--assessed whether statins provide perioperative cardiovascular protection; 12 studies enrolled patients undergoing non-cardiac vascular surgery, four enrolled patients undergoing coronary bypass surgery, and two enrolled patients undergoing various surgical procedures. In the randomised trials the summary odds ratio for death or acute coronary syndrome during the perioperative period with statin use was 0.26 (95% confidence interval 0.07 to 0.99) and the summary odds ratio in the cohort studies was 0.70 (0.57 to 0.87). Although the pooled cohort data provided a statistically significant result, statins were not randomly allocated, results in retrospective studies were larger (odds ratio 0.65, 0.50 to 0.84) than those in the prospective cohorts (0.91, 0.65 to 1.27), and dose, duration, and safety of statin use was not reported.

CONCLUSION

The evidence base for routine administration of statins to reduce perioperative cardiovascular risk is inadequate.

Review article: The role of statins in reducing perioperative cardiac risk: physiologic and clinical perspectives

PURPOSE

To review the pathobiology and clinical implications of coronary vulnerable atherosclerotic plaques (VAPs), to discuss the role of statin therapy in VAP stabilization, and the potential benefits of perioperative statin therapy (PST) in reducing perioperative risk of acute coronary syndromes (ACSs).

SOURCE

MEDLINE search using "perioperative", "cardiac morbidity", "atherosclerosis", "vulnerable plaque", "statins" and combinations of these terms as keywords. The reference lists of relevant articles were further reviewed to identify additional citations.

PRINCIPAL FINDINGS

The nonstenotic, yet rupture-prone VAP causes most myocardial infarctions (MIs) and other ACSs, both in the nonsurgical and surgical patients. Large clinical trials in both primary and secondary prevention and in patients with ACSs have demonstrated that statin therapy will reduce cardiovascular morbidity and mortality across a broad spectrum of patient subgroups. These trials also suggest, and laboratory investigations establish, that statins possess favourable vascular effects independent of cholesterol reduction. Statins appear to interfere specifically with the pathophysiologic mechanisms implicated in atherothrombotic disease. Statins reduce vascular inflammation, improve endothelial function, stabilize VAPs, and reduce platelet aggregability and thrombus formation. Recent studies have shown that PST is associated with a reduced incidence of perioperative and long-term cardiovascular complications in high-risk patients. Combined therapy with statins and ss-blockers is a conceptually valid strategy targeting critical steps in the pathogenesis of an ACS.

CONCLUSION

Emerging evidence for the efficacy and safety of PST is promising, especially when combined with ss-blocker therapy in patients at highest risk. Confirmation of this early evidence awaits the results of ongoing and future prospective randomized controlled trials.

Can Statins Reduce Perioperative Morbidity and Mortality in Patients Undergoing Non-Cardiac Vascular Surgery?

AIMS

To determine whether statins can reduce perioperative morbidity and mortality in patients undergoing non-cardiac vascular surgery.

METHODS

A search using Pubmed was performed to identify reports in English. The search terms were: "statins", "perioperative morbidity", "perioperative mortality" and "vascular surgery". We excluded studies dealing with the effect of statins in cardiac surgery. Retrieved articles were manually searched.

RESULTS

Current evidence shows that statins decrease perioperative morbidity and mortality in patients undergoing non-cardiac vascular surgery. Any benefit probably occurs soon (within a month) after initiating treatment.

CONCLUSIONS

Appropriately designed trials need to confirm the beneficial effect of perioperative statin therapy in various patient categories. The optimal duration and dose of perioperative statin therapy should be defined.

Excellent anaesthesia needs patient preparation and postoperative support to influence outcome

PURPOSE OF REVIEW

Studies over many years have demonstrated that preoptimization and attention to appropriate perioperative care is associated with a substantial decrease in surgical mortality. This review discusses ways in which patient preparation and perioperative support can minimize surgical mortality and morbidity.

RECENT FINDINGS

Scoring systems continue to be developed in order to classify categories of surgical risk. Objective physiologically based assessments can also identify high-risk groups of patients. Debate continues over the indications for specific interventions such as beta-blockade or statin therapy. There is continuing interest in perioperative optimization of oxygen delivery. A multimodality approach paying attention to a range of possible interventions appears to be beneficial. Audit, training, experience and a sufficient volume of procedures are all factors associated with surgical mortality.

SUMMARY

The provision of a high-quality service throughout the perioperative period is vital for a successful outcome. Patients need to be assessed well before major elective surgery to determine if they fall into a high-risk category. Some patients may benefit from a change in management. Postoperatively, critical-care support should be available backed by level 1 (enhanced ward) care with input from outreach or medical emergency teams 24 hours per day, seven days a week.

The pharmacoeconomics of peri-operative beta-blocker therapy

It is widely recommended that beta-blockade be used peri-operatively as it may reduce the incidence of postoperative cardiovascular complications including death. However, there are few data concerning the cost-effectiveness of such strategies. We have analysed the pharmacoeconomics of acute beta-blockade using data from eight prospective peri-operative studies in which patients underwent elective non-cardiac surgery, and in which the incidence of adverse side-effects of treatment, as well as clinical outcomes, have been reported. The costs of treatment were based on the NHS reference costs for 2004. From these data, the number-needed-to-treat (NNT) to prevent a major cardiovascular complication (including cardiovascular death) in high-risk patients was 18.5. This is comparable to the NNT for peri-operative statin therapy. The incremental cost of peri-operative beta-blockade (costs of drug acquisition and of treating associated adverse drug events) was 67.80 pounds sterling per patient. This results in a total cost of 1254.30 pounds sterling per peri-operative cardiovascular complication prevented. However, there is evidence that in patients at lower cardiovascular risk, beta-blockers may be potentially harmful, since their adverse effects (hypotension, bradycardia) may outweigh their potential cardioprotective effects.