Perioperative beta blockade: where do we go from here?

Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery

The Canadian Cardiovascular Society Guidelines Committee and key Canadian opinion leaders believed there was a need for up to date guidelines that used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system of evidence assessment for patients who undergo noncardiac surgery. Strong recommendations included: 1) measuring brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) before surgery to enhance perioperative cardiac risk estimation in patients who are 65 years of age or older, are 45-64 years of age with significant cardiovascular disease, or have a Revised Cardiac Risk Index score ≥ 1; 2) against performing preoperative resting echocardiography, coronary computed tomography angiography, exercise or cardiopulmonary exercise testing, or pharmacological stress echocardiography or radionuclide imaging to enhance perioperative cardiac risk estimation; 3) against the initiation or continuation of acetylsalicylic acid for the prevention of perioperative cardiac events, except in patients with a recent coronary artery stent or who will undergo carotid endarterectomy; 4) against α₂ agonist or β-blocker initiation within 24 hours before surgery; 5) withholding angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker starting 24 hours before surgery; 6) facilitating smoking cessation before surgery; 7) measuring daily troponin for 48 to 72 hours after surgery in patients with an elevated NT-proBNP/BNP measurement before surgery or if there is no NT-proBNP/BNP measurement before surgery, in those who have a Revised Cardiac Risk Index score ≥1, age 45-64 years with significant cardiovascular disease, or age 65 years or older; and 8) initiating of long-term acetylsalicylic acid and statin therapy in patients who suffer myocardial injury/infarction after surgery.

Sympathetic autonomic dysfunction and impaired cardiovascular performance in higher risk surgical patients: implications for perioperative sympatholysis

Objective

Recent perioperative trials have highlighted the urgent need for a better understanding of why sympatholytic drugs intended to reduce myocardial injury are paradoxically associated with harm (stroke, myocardial infarction). We hypothesised that following a standardised autonomic challenge, a subset of patients may demonstrate excessive sympathetic activation which is associated with exercise-induced ischaemia and impaired cardiac output.

Methods

Heart rate rise during unloaded pedalling (zero workload) prior to the onset of cardiopulmonary exercise testing (CPET) was measured in 2 observation cohorts of elective surgical patients. The primary outcome was exercise-evoked, ECG-defined ischaemia (>1 mm depression; lead II) associated with an exaggerated increase in heart rate (EHRR ≥12 bpm based on prognostic data for all-cause cardiac death in preceding epidemiological studies). Secondary outcomes included cardiopulmonary performance (oxygen pulse (surrogate for left ventricular stroke volume), peak oxygen consumption (VO_2peak), anaerobic threshold (AT)) and perioperative heart rate.

Results

EHRR was present in 40.4–42.7% in both centres (n=232, n=586 patients). Patients with EHRR had higher heart rates perioperatively (p<0.05). Significant ST segment depression during CPET was more common in EHRR patients (relative risk 1.7 (95% CI 1.3 to 2.1); p<0.001). EHRR was associated with 11% (95%CI 7% to 15%) lower predicted oxygen pulse (p<0.0001), consistent with impaired left ventricular function.

Conclusions

EHRR is common and associated with ECG-defined ischaemia and impaired cardiac performance. Perioperative sympatholysis may further detrimentally affect cardiac output in patients with this phenotype.

Learning from mistakes in clinical practice guidelines: the case of perioperative β-blockade

For more than two decades, the role of beta-blockers in preventing cardiac complications after major surgery has been the subject of contentious scientific and policy debate. Based on two small but highly publicized randomized trials published in 1996 and 1999, prominent U.S. organizations embraced preoperative beta-blocker initiation as a “best practice” and an opportunity for widespread safety improvement. Yet only a few years later, expert recommendations regarding preoperative beta-blockers were revised and downgraded when subsequent research failed confirm promising early findings and called attention to potential harms associated with beta-blocker overuse. In this paper, we trace the history of preoperative beta-blocker recommendations as a case study in lessons to be learned from reversals of guideline recommendations based initially on evidence drawn from randomized, controlled trials. Ultimately, we find that the policy significance that stakeholders ascribed to early beta-blocker studies combined with the prestige that experts assigned to the randomized controlled trial as a form of evidence to short-circuit discourse on the risks of preoperative beta-blocker initiation and led it to be elevated prematurely as a best practice. As such, the story of preoperative beta-blockers illustrates threats to objectivity in guidelines that can emerge from policy imperatives that lend primacy to the rapid translation of research into practice and from perspectives that unduly emphasize the strengths of randomized trials.

Effectiveness of preoperative beta-blockade on intra-operative heart rate in vascular surgery cases conducted under regional or local anesthesia

BACKGROUND

Preoperative β-blockade has been posited to result in better outcomes for vascular surgery patients by attenuating acute hemodynamic changes associated with stress. However, the incremental effectiveness, if any, of β-blocker usage in blunting heart rate responsiveness for vascular surgery patients who avoid general anesthesia remains unknown.

METHODS

We reviewed an existing database and identified 213 consecutive vascular surgery cases from 2005-2011 conducted without general anesthesia (i.e., under monitored anesthesia care or regional anesthesia) at a tertiary care Veterans Administration medical center and categorized patients based on presence or absence of preoperative β-blocker prescription. For this series of patients, with the primary outcome of maximum heart rate during the interval between operating room entry to surgical incision, we examined the association of maximal heart rate and preoperative β-blocker usage by performing crude and multivariate linear regression, adjusting for relevant patient factors.

RESULTS

Of 213 eligible cases, 137 were prescribed preoperative β-blockers, and 76 were not. The two groups were comparable across baseline patient factors and intraoperative medication doses. The β-blocker group experienced lower maximal heart rates during the period of evaluation compared to the non-β-blocker group (85 ± 22 bpm vs. 98 ± 36 bpm, respectively; p = 0.002). Adjusted linear regression confirmed a statistically-significant association between lower maximal heart rate and the use of β-blockers (Beta = -11.5; 95% CI [-3.7, -19.3] p = 0.004).

CONCLUSIONS

The addition of preoperative β-blockers, even when general anesthesia is avoided, may be beneficial in further attenuating stress-induced hemodynamic changes for vascular surgery patients.

Perioperative Metoprolol and Risk of Stroke after Noncardiac Surgery

Background:

Numerous risk factors have been identified for perioperative stroke, but there are conflicting data regarding the role of β adrenergic receptor blockade in general and metoprolol in particular.

Methods:

The authors retrospectively screened 57,218 consecutive patients for radiologic evidence of stroke within 30 days after noncardiac procedures at a tertiary care university hospital. Incidence of perioperative stroke within 30 days of surgery and associated risk factors were assessed. Patients taking either metoprolol or atenolol were matched based on a number of risk factors for stroke. Parsimonious logistic regression was used to generate a preoperative risk model for perioperative stroke in the unmatched cohort.

Results:

The incidence of perioperative stroke was 55 of 57,218 (0.09%). Preoperative metoprolol was associated with an approximately 4.2-fold increase in perioperative stroke (P &lt; 0.001; 95% CI, 2.2–8.1). Analysis of matched cohorts revealed a significantly higher incidence of stroke in patients taking preoperative metoprolol compared with atenolol (P = 0.016). However, preoperative metoprolol was not an independent predictor of stroke in the entire cohort, which included patients who were not taking β blockers. The use of intraoperative metoprolol was associated with a 3.3-fold increase in perioperative stroke (P = 0.003; 95% CI, 1.4–7.8); no association was found for intraoperative esmolol or labetalol.

Conclusions:

Routine use of preoperative metoprolol, but not atenolol, is associated with stroke after noncardiac surgery, even after adjusting for comorbidities. Intraoperative metoprolol but not esmolol or labetalol, is associated with increased risk of perioperative stroke. Drugs other than metoprolol should be considered during the perioperative period if β blockade is required.

β-Adrenergic blockade in cardiovascular disease

The development and subsequent clinical application of the β-adrenergic receptor blocking drugs represent one of the major advances in human pharmacotherapeutics. No other class of synthetic drugs has demonstrated such widespread therapeutic utility for the treatment and prevention of so many cardiovascular diseases. In addition, these drugs have proven to be molecular probes that have contributed to our understanding of the disease, and on the molecular level, both the structure and function of the 7 transmembrane G protein receptors that mediate the actions of many different hormones, neurotransmitters, and drugs. The evolution of β-blocker drug development has led to refinements in their pharmacodynamic actions that include agents with relative β1-selectivity, partial agonist activity, concomitant α-adrenergic blockers activity, and direct vasodilator activity. In addition, long-acting and ultra-short-acting formulations of β-blockers have also demonstrated a remarkable record of clinical safety in patients of all ages.

Beta-Blocker management in High-Risk Patients Presenting for Non-Cardiac Surgery: Before and after the POISE Trial

The POISE Trial was a randomised, placebo-controlled, double-blind study of the effectiveness of perioperative beta-blockade in preventing cardiac events including death in 8351 patients. Our hypothesis was that knowledge of the results of the POISE Trial would either increase or decrease the use of effective perioperative beta-blockade, depending on the result. Patients presenting for non-cardiac surgery and at risk of perioperative cardiac events were recruited in two cohorts before and after the release of the POISE Trial results. Effective perioperative beta-blockade was defined as heart rate <65 beats per minute for at least 80% of the perioperative period in patients prescribed beta-blockers. Effective perioperative beta-blockade was achieved in 22 (11.5%) of 191 patients prescribed perioperative beta-blockade in the first cohort (n=392) and seven (6%) of 118 patients in the second cohort (n=241) (P=0.10). Effective heart rate control was achieved in 29 (9%) patients prescribed perioperative beta-blockers compared with 10 (3%) patients not prescribed perioperative beta-blockers (P=0.001). The rate of implementation of effective beta-blockade was low before POISE and this did not change significantly after publication. Our finding does not provide reliable evidence of a change in practice as a result of the POISE Trial.

Treatment recommendations to prevent myocardial ischemia and infarction in patients undergoing vascular surgery

During major vascular surgery (MVS), patients are at high risk for developing unrecognized myocardial infarction (MI) and myocardial ischemia. In reducing postoperative morbidity and mortality, preoperative cardiac risk stratification and adequate medical therapy play a pivotal role. Based on literature and current opinions, medical treatment should comprise at least a combination of beta-blockers, aspirin, and statins. beta-Blockers exert their beneficial effects predominantly through heart rate control, leading to reduced oxygen demand during surgery. A heart rate between 65 and 70 bpm should be achieved. Irrespective of their lipid-lowering effects, statins seem to improve postoperative cardiac outcome by stabilizing coronary artery plaques, thereby preventing atherosclerotic plaque rupture. Aspirin reduces platelet activation and vasoconstriction, thereby limiting ischemic events and reducing nonfatal MI by 34%. Adding clopidogrel to low-dose aspirin might be beneficial toward postoperative cardiac outcomes; however, the effect on the incidence of postoperative bleeding complications may be a problem for future studies to resolve. Whereas beta-blockers inhibit the effect of catecholamines, alpha(2)-agonists inhibit catecholamine release and may be used in the perioperative setting when beta-blockers are contraindicated. Despite the blood pressure-lowering effect and anti-inflammatory properties of angiotensin-converting enzyme inhibitors, the literature does not support their use in patients undergoing MVS. The possible use of calcium antagonists before MVS should be further evaluated in high-risk patients with contraindications to beta-blockers, such as asthma, conduction abnormalities, or a history of stroke. Although nitrates are widely used for treating angina pectoris, the beneficial effect of their use in patients undergoing MVS remains controversial. Therefore, nitrates are not routinely used in the perioperative setting. The current American College of Cardiology/American Heart Association guidelines do not recommend prophylactic coronary revascularization before noncardiac surgery in patients with stable coronary artery disease.

Cardioprotective effects of perioperative β-blockade in vascular surgery patients: fact or fiction?

PURPOSE OF REVIEW

Perioperative β-blockade remains a subject of debate. In this review, recent literature and current guidelines for perioperative β-blockade in vascular surgery patients are discussed.

RECENT FINDINGS

Available evidence suggests that perioperative β-blockade may be beneficial in reducing cardiac events. However, in a recent large study, the incidences of stroke and mortality were increased in patients on perioperative β-blockers. Large systematic reviews failed to demonstrate a net beneficial effect of perioperative β-blockers. The 2009 American and the European guidelines for perioperative β-blockade in vascular surgery disagree on the available evidence but do recommend β-blockade for several indications. Most recent, Wallace and colleagues published a large-sized retrospective study, reporting a beneficial effect of the adoption of a protocol for perioperative β-blockade.

SUMMARY

Perioperative β-blockade reduces cardiac events, but at the expense of increased risk for mortality and stroke. The guidelines seem to be eager to follow positive outcome studies, without considering the effects of β-blockade on other organ systems. Perhaps the main reason for the reported cardioprotective effects of perioperative β-blocker therapy should be sought in failing preoperative β-blocker prophylaxis (irrespective of surgery).

ACE inhibitors in cardiac surgery: current studies and controversies

Major complications associated with cardiac surgery are still common and carry great prognostic significance. Current medical interventions to prevent these cardiovascular complications include antiplatelet therapy, statins, β-blockers and angiotensin-converting enzyme (ACE) inhibitors. Both experimental studies and clinical trials have shown that ACE inhibitors hold promise as cardiovascular protective agents for cardiac surgery patients. Several lines of evidence support this hypothesis. First, long-term use of ACE inhibitors has been well established to provide cardiovascular protection and reduce ischemic events and complications, independent of their effect on heart function and blood pressure. Second, early ACE inhibitor therapy has been demonstrated to produce remarkable survival and heart function benefits in patients with acute myocardial infarction. Third, ACE blockage can prevent or delay the development or progression of renal disease at all stages, from subclinical microalbuminuria to end-stage renal disease. Nevertheless, perioperative studies of the effects of ACE inhibitors remain few and inconclusive. Results from recent clinical trials and observational studies are conflicting and raise more questions than answers. Further studies, both retrospective and larger-scale prospective studies, are critically needed to examine whether ACE inhibitors reduce mortality and major complications in patients undergoing cardiac surgery.

[Non-cardiac surgery in patients with cardiac disease]

BACKGROUND

Patients with cardiac disease have a higher incidence of cardiovascular events after non-cardiac surgery than those without such disease. This paper provides an overview of perioperative examinations and treatment.

MATERIAL AND METHODS

Own experience and systematic literature search through work with European guidelines constitute the basis for recommendations given in this article.

RESULTS

Beta-blockers should not be discontinued before surgery. High-risk patients may benefit from beta-blockers administered before major non-cardiac surgery. Slow dose titration is recommended. Echocardiography should be performed before preoperative beta-blockade to exclude latent heart failure. Statins should be considered before elective surgery and coronary intervention (stenting or surgery) before high-risk surgery. Otherwise, interventions should be evaluated irrespective of planned non-cardiac surgery. Patients with unstable coronary syndrome should only undergo non-cardiac surgery on vital indications. Neuraxial techniques are optimal for postoperative pain relief and thus for postoperative mobilization. Thromboprophylaxis is important, but increases the risk of epidural haematoma and requires systematic follow-up with respect to diagnostics and treatment.

INTERPRETATION

Little evidence supports the use of different anaesthetic methods in cardiac patients that undergo non-cardiac surgery than in other patients. Stable circulation, sufficient oxygenation, good pain relief, thromboprophylaxis, enteral nutrition and early mobilization are important factors for improving the perioperative course. Close cooperation between anaesthesiologist, surgeon and cardiologist improves logistics and treatment.

The effect of landiolol on cerebral blood flow in patients undergoing off-pump coronary artery bypass surgery

PURPOSE

To examine the effect of landiolol on cerebral blood flow in patients with normal or deteriorated cardiac function.

METHODS

Thirty adult patients who were diagnosed with angina pectoris and who underwent elective off-pump coronary artery bypass surgery were studied. Patients were divided into two groups, one with a preoperative left ventricular ejection fraction (EF) of 50% or higher (normal EF group; n = 15) and the other with an EF of less than 50% (low EF group; n = 15). The mean cerebral blood flow velocity (Vmca) and pulsatility index (PI) in the middle cerebral artery were recorded using transcranial Doppler ultrasonography (TCD). Individual hemodynamic data were obtained using a pulmonary arterial catheter.

RESULTS

In both groups, landiolol produced a significant decrease in heart rate (HR), which then returned to baseline 15 min after administration was completed. A significant decrease in mean arterial pressure occurred in the low EF group, but the decrease was within 30% of the baseline. In the normal EF group, there was no decrease in cardiac index (CI), whereas in the low EF group, CI significantly decreased along with the decrease in HR. There were no significant differences in Vmca and PI between the two groups.

CONCLUSION

Continuous administration of landiolol at a dose of 0.04 mg/kg/min after 1 min rapid i.v. administration at a dose of 0.125 mg/kg/min decreases HR without causing aggravation of CBF during treatment of intraoperative tachycardia in patients with normal and deteriorated cardiac function.

Morbidity and mortality caused by cardiac adverse events after revascularization for critical limb ischemia

BACKGROUND

We assessed cardiac adverse events (AEs) after primary lower extremity arterial revascularization (LEAR) for critical lower limb ischemia (CLI) in order to evaluate the impact of cardiac AEs on the clinical outcome. We created an optimized care protocol concerning CLI patients' preoperative work-up as well as intra- and postoperative surveillance according to recent important literature and guidelines.

METHODS

We conducted a prospective analysis of clinical outcome after LEAR using patient-related risk factors, comorbidity, surgical therapy, and AEs. This cohort was divided into patients with and without AEs. AEs were categorized according to predefined standards: minor, surgical, failed revascularization, and systemic. The consequences of AEs were reoperation, additional medication, irreversible physical damage, and early death.

RESULTS

There were 106 patients (Fontaine III n=49, 46%, and Fontaine IV n=57, 56%) who underwent primary revascularization by bypass graft procedure (n=67, 63%) or balloon angioplasty (n=39, 37%). No difference in comorbidity was registered between the two groups. Eighty-four AEs were registered in 34 patients (32%). Patients experiencing AEs had significantly less antiplatelet agents (without AEs n=63, 88%, vs. with AEs n=18, 53%; p=0.000) and/or beta-blockers (without AEs n=66, 92%, vs. with AEs n=16, 47%; p=0.000) compared to patients without AEs. The two most harmful consequences of AEs were irreversible physical damage (n=3) and early death (n=8). Sixty percent (n=9) of systemic AEs were heart-related. The postprocedural mortality rate was 7.5%, with a 75% (n=6) heart-related cause of death.

CONCLUSION

AEs occur in >30% of CLI patients after LEAR. The most harmful AEs on the clinical outcome of CLI patients were heart-related, causing increased morbidity and death. Significant correlations between prescription of beta-blockers and antiplatelet agents and prevention of AEs were observed. A persistent focus on the prevention of systemic AEs in order to ameliorate the outcome after LEAR for limb salvage remains of utmost importance. Therefore, we advise the implementation of an optimized care protocol by discussing patients in a strict manner according to a predetermined protocol, to optimize and standardize the preoperative work-up as well as intra- and postoperative patient surveillance.

Cardiovascular problems in noncardiac surgery

PURPOSE OF REVIEW

Perioperative cardiac complications remain a major area of concern as our surgical population increases in volume, age and frequency of comorbidity. A variety of strategies can be used to optimize patients and potentially reduce the incidence of these serious complications.

RECENT FINDINGS

Recent literature suggests a trend towards less invasive testing for detection and quantification of coronary artery disease and greater interest in pharmacologic 'cardioprotection' using beta-blockers, statins and other agents targeting heart rate control and other mechanisms (e.g. reducing inflammatory responses). The recent Perioperative Ischemic Evaluation study has substantially altered this approach at least towards widespread application to lower/intermediate risk cohorts. Considerable attention has been focused on ensuring optimal standardized perioperative management of patients with a recent percutaneous coronary intervention, particularly those with an intracoronary stent. Widespread surveillance of postoperative troponin release and increasing recognition of the prognostic potential of elevated preoperative brain natriuretic peptides point towards changing strategies for long-term risk stratification.

SUMMARY

The complexity of a particular patient's physiologic responses to a wide variety of surgical procedures, which are undergoing constant technological refinement generally associated with lesser degrees of invasivity and stress make calculation of patients' perioperative risk very challenging. At the present time, adequate information is available for the clinician to screen patients with high-risk preoperative predictors, delay elective surgery for patients with recent intracoronary stents and continue chronic beta-blockade in appropriate patients. New large-scale database and subanalyses of major trials (e.g. Perioperative Ischemic Evaluation and Coronary Artery Revascularization Prophylaxis) should provide additional information to minimize perioperative cardiac risk.

Effect of chronic beta-blocker use on stroke after noncardiac surgery

The incidence of postoperative stroke ranges from 0.08% to 0.7% in noncardiac surgery. Recently, the PeriOperative ISchemic Evaluation (POISE) study reported an incidence of postoperative stroke of 1% in patients scheduled for noncardiac surgery when beta blockers were initiated immediately before surgery. To assess the association between chronic beta-blocker use and postoperative stroke in noncardiac surgery, we undertook a case-control study among 186,779 patients who underwent noncardiac surgery from 2000 to 2008 at the Erasmus Medical Centre. Patients who were undergoing intracerebral surgery or carotid surgery or who had head and/or carotid trauma were excluded. The case subjects were 34 patients (0.02%) who had experienced a stroke within 30 days after surgery. Of the remaining patients, 2 controls were selected for each case and were stratified according to calendar year, type of surgery, and age. For cases and controls, information was obtained regarding beta-blocker use before surgery, the presence of cardiac risk factors, and the use of other cardiovascular medication. The use of beta blockers was as common in the cases as in the controls (29% vs 29%; p = 1.0). The adjusted odds ratio for postoperative stroke among beta-blocker users compared with nonusers was 0.4 (95% confidence interval 0.1 to 1.5). Similar results were obtained in the subgroups of patients stratified according to the use of cardiovascular therapy and the presence of cardiac risk factors. In conclusion, the present case-control study has shown no increased risk of postoperative stroke in patients taking chronic beta-blocker therapy.

Preoperative screening, evaluation, and optimization of the patient's medical status before outpatient surgery

PURPOSE OF THE REVIEW

Preoperative evaluation and optimization of a patient's medical condition are important components of anesthesia practice. With ever increasing numbers of patients with serious comorbidities having complex procedures as outpatients, the task of gathering information and properly preparing for their care is challenging. Improvements in assessment and management can potentially reduce adverse events, improve patient and caregiver satisfaction, and reduce costs.

RECENT FINDINGS

A growing body of literature and evidence-based practices and guidelines can assist clinicians who work in the expanding field of preoperative medicine. Care providers from various specialties in medicine are developing innovative methods, tools, and knowledge to advance science and processes. Data-driven practices are beginning to close the information gap that has plagued this field of medical practice.

SUMMARY

Preparation of patients before surgery is a necessary and vital component of perioperative medicine. Practices are developing to guide effective interventions that benefit patients and healthcare systems. Outpatients present special challenges to preoperative assessment.

Perioperative cardiovascular assessment of patients undergoing noncardiac surgery

Preoperative assessment of the cardiac patient before noncardiac surgery is common in the clinical practice of the medical consultant, anesthesiologist, and surgeon. Currently, most noncardiac surgical procedures are performed for patients of advanced age, and the number of such surgeries is likely to increase with the aging of the population. These same patients have an increased prevalence of cardiovascular disease, especially ischemic heart disease, which is the primary cause of perioperative morbidity and mortality associated with noncardiac surgery. Since 1996, 3 American College of Cardiology/American Heart Association guideline documents have been published, each reflecting the available literature, with recommendations for the preoperative cardiovascular evaluation and treatment of the patient undergoing noncardiac surgery. Our review describes the 2007 American College of Cardiology/American Heart Association guidelines, the most recent revision, focusing on a newly recommended 5-step algorithmic approach to managing this clinical problem, particularly for the patient with known or suspected coronary heart disease. Continued emphasis should be given to preoperative clinical risk stratification, with noninvasive testing reserved for those patients in whom a substantial change in medical management would be anticipated based on results of testing. Pharmacologic therapy holds more promise than coronary revascularization for the reduction of major adverse perioperative cardiac events that might complicate noncardiac surgery.

Perioperative cardiovascular assessment of patients undergoing noncardiac surgery

Preoperative assessment of the cardiac patient before noncardiac surgery is common in the clinical practice of the medical consultant, anesthesiologist, and surgeon. Currently, most noncardiac surgical procedures are performed for patients of advanced age, and the number of such surgeries is likely to increase with the aging of the population. These same patients have an increased prevalence of cardiovascular disease, especially ischemic heart disease, which is the primary cause of perioperative morbidity and mortality associated with noncardiac surgery. Since 1996, 3 American College of Cardiology/American Heart Association guideline documents have been published, each reflecting the available literature, with recommendations for the preoperative cardiovascular evaluation and treatment of the patient undergoing noncardiac surgery. Our review describes the 2007 American College of Cardiology/American Heart Association guidelines, the most recent revision, focusing on a newly recommended 5-step algorithmic approach to managing this clinical problem, particularly for the patient with known or suspected coronary heart disease. Continued emphasis should be given to preoperative clinical risk stratification, with noninvasive testing reserved for those patients in whom a substantial change in medical management would be anticipated based on results of testing. Pharmacologic therapy holds more promise than coronary revascularization for the reduction of major adverse perioperative cardiac events that might complicate noncardiac surgery.

Delirium after elective surgery among elderly patients taking statins

BACKGROUND

Postoperative delirium after elective surgery is frequent and potentially serious. We sought to determine whether the use of statin medications was associated with a higher risk of postoperative delirium than other medications that do not alter microvascular autoregulation.

METHODS

We conducted a retrospective cohort analysis of 284 158 consecutive patients in Ontario aged 65 years and older who were admitted for elective surgery. We identified exposure to statins from outpatient pharmacy records before admission. We identified delirium by examining hospital records after surgery.

RESULTS

About 7% (n = 19 501) of the patients were taking statins. Overall, 3195 patients experienced postoperative delirium; the rate was significantly higher among patients taking statins (14 per 1000) than among those not taking statins (11 per 1000) (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.15-1.47, p < 0.001). The increased risk of postoperative delirium persisted after we adjusted for multiple demographic, medical and surgical factors (OR 1.28, 95% CI 1.12-1.46) and exceeded the increased risk of delirium associated with prolonging surgery by 30 minutes (OR 1.20, 95% CI 1.19-1.21). The relative risk associated with statin use was somewhat higher among patients who had noncardiac surgery than among those who had cardiac surgery (adjusted OR 1.33, 95% CI 1.16-1.53), and extended to more complicated cases of delirium. We did not observe an increased risk of delirium with 20 other cardiac or noncardiac medications.

INTERPRETATION

The use of statins is associated with an increased risk of postoperative delirium among elderly patients undergoing elective surgery.

Long-term cardiac outcome in high-risk patients undergoing elective endovascular or open infrarenal abdominal aortic aneurysm repair

OBJECTIVES

To assess long-term outcome of patients at high cardiac risk undergoing endovascular or open AAA repair.

METHODS

Patients undergoing open or endovascular infrarenal AAA repair with >or=3 cardiac risk factors and preoperative cardiac stress testing (DSE) at 2 university hospitals were studied. Main outcome was cardiac event free and overall survival. Multivariate Cox regression analysis was used to evaluate the influence of type of AAA repair on long-term outcome.

RESULTS

In 124 patients (55 endovascular, 69 open) the number and type of cardiac risk factors, medication use and DSE results were similar in both groups. In multivariable analysis, adjusting for cardiac risk factors, stress test results, medication use, and propensity score endovascular repair was associated with improved cardiac event free survival (HR 0.54; 95% CI 0.30-0.98) but not with an overall survival benefit (HR 0.73; 95% CI 0.37-1.46). Importantly, statin therapy was associated with both improved overall survival (HR 0.42; 95% CI 0.21-0.83) and cardiac event free survival (HR 0.45; 95% CI 0.23-0.86).

CONCLUSIONS

The perioperative cardiac benefit of endovascular AAA repair in high cardiac risk patients is sustained during long-term follow-up provided patients are on optimal medical therapy but it is not associated with improved overall long-term survival.

[Perioperative pharmacological myocardial protection. Systematic literature-based process optimization]

Patients with major cardiac risk factors have been suggested to benefit from perioperative beta-blockade. However, the scientific literature on perioperative beta-blockade needs to be interpreted carefully. So far treatment recommendations for millions of patients are based on heterogeneous data from randomized trials with divergent study results. The evidence for a beneficial effect of perioperative beta-blockers is sufficient only for a limited subpopulation of high cardiac risk patients undergoing vascular surgery. Perioperative beta-blocker treatment is not useful in patients with intermediate risk and may even be harmful in patients with low cardiac risk. Therefore, an individualized risk-benefit analysis is an important prerequisite for a rational therapy that may be based on a standardized protocol including the Revised Cardiac Risk Index. Such a protocol is presented in this article. A recently reported trial (POISE) demonstrated that perioperative treatment with high doses of oral metoprolol efficiently reduces the incidence of cardiovascular events. However, due to severe adverse effects (hypotension, bradycardia, stroke) the total mortality was increased. Thus, dose adjustments, safety aspects, and monitoring of beta-blocker therapy seem to be mandatory. So far evidence from relevant trials about how to best implement perioperative beta-blockade is lacking. This article offers a simple clinical concept for this purpose.

Recently published papers: Renal replacement therapy: which route and how much? Intracerebral haematomas: does the size matter? Beta blockers and steroids: will we ever know?

Femoral access for renal replacement therapy appears to have a similar infection rate to jugular access. High-intensity renal support does not seem to improve mortality or length of hospital stay. Acute kidney injury as defined by Acute Kidney Injury Network predicts increased hospital mortality. Recombinant factor VIIa reduces growth of volume of intracerebral haematoma but does not affect clinical outcome. Sustained released metoprolol reduces perioperative cardiac events in non-cardiac surgery but leads to more deaths and strokes. Steroids are probably not beneficial in either children with non-Haemophilus influenzae type b bacterial meningitis, or in prophylaxis of acute respiratory distress syndrome (ARDS), but could be beneficial in the treatment of ARDS.