Effect of atenolol on mortality and cardiovascular morbidity after noncardiac surgery

Perioperative β-Blockers in Patients Undergoing Noncardiac Surgery-Scientific Misconduct and Clinical Guidelines

BACKGROUND

β-blocker use in perioperative period of noncardiac surgeries has been a topic of debate since many years. Earlier studies conducted in the 90s showed decreased cardiac adverse events and improved postoperative outcomes with β-blocker use. Based on this, the ACCF and ESC published guidelines strongly supporting β-blocker use. But contemporaneous studies conducted revealed conflicting evidence and have also proven some of the earlier studies to be fraudulent. Although ACCF guidelines have been updated to partially reflect the changes, ESC guidelines continue to support β-blocker use.

AREAS OF UNCERTAINTY

In light of the ACCF and ESC guidelines supporting β-blocker use in perioperative period of noncardiac surgeries, our aim was to review the available literature and consolidate evidence in this regard.

DATA SOURCES

PubMed search was conducted to include relevant studies between 1950 and 2015.

RESULTS

We reviewed 24 eligible studies and few debates conducted in this regard. Based on our review, our findings were as follows: β-blockers should be continued throughout perioperative period in patients who were on β-blockers before surgery for other indications such as angina, hypertension, and symptomatic arrhythmias. Preoperative β-blockers are indicated in patients undergoing high risk vascular surgery or those having high preoperative Cardiac Risk Index Score. In patients with intermediate-to-low cardiac risk, the proven benefit is not sufficient enough to suggest universal use.

CONCLUSIONS

Based on our review, we conclude that the use of β-blockers in perioperative period of noncardiac surgeries should be determined on an individual basis based on risk-benefit analysis. Guideline organizations should update their recommendations based on new evidence.

Perioperative β-Blockade in Noncardiac Surgery: A Cautionary Tale of Over-reliance on Small Randomized Prospective Trials

PURPOSE

Our aim was to analyze the current scientific literature relevant to the use of β-adrenergic receptor antagonists for the prevention of cardiovascular morbidity and mortality in patients undergoing noncardiac surgery.

METHODS

A PubMed search was conducted for the following concepts: pre- or perioperative, β-adrenergic receptor antagonist, treatment outcome, and cardiovascular complication. Randomized clinical trials measuring the effect of β-adrenergic blocking agents against that of placebo on cardiovascular outcomes after noncardiac surgery were included in the review.

FINDINGS

Two small randomized controlled trials published in 1996 and 1999 reported associations between perioperative β-blockade and significant reductions in long-term and 30-day cardiac mortality, respectively. These 2 studies prompted guideline changes in 2002 encouraging perioperative β-blockade in subsets of noncardiac surgery patients. However, subsequent trials failed to validate these results. In 2008, the first large randomized controlled trial on the topic was published and found an association between perioperative β-blockade and an increase in perioperative mortality. Furthermore, in 2011, the lead author of the 1999 study was dismissed from his academic position for scientific misconduct, casting doubt on the validity of guidelines based on his work. Existing studies are highly heterogeneous, making comparisons difficult. Current literature does not support initiating perioperative β-blockade in noncardiac surgery patients not already receiving these medications.

IMPLICATIONS

Future research on the topic should account for the influence individual genetic variation can have on outcomes and β-blocker metabolism. Additionally, the relationship between outcomes and the β-1 selectivity of different β-blockers should be explored.

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.

Preoperative cardiac risk stratification 2007: evolving evidence, evolving strategies

Various guidelines and risk indices have optimized cardiac risk stratification, and the emphasis has shifted to reducing perioperative risk. This review is an update on invasive (CABG/PCI) and noninvasive (medical therapy with beta-blockers, alpha-agonists, and statins) strategies to reduce cardiac risk for noncardiac surgery and the controversies surrounding their use.

Development of a perioperative medicine research agenda: a cross sectional survey

BACKGROUND

Post-operative complications are a significant source of morbidity and mortality for patients undergoing surgery. However, there is little research in the emerging field of perioperative medicine beyond cardiac risk stratification. We sought to determine the research priorities for perioperative medicine using a cross sectional survey of Canadian and American general internists.

METHODS

Surveys were electronically sent to 312 general internists from the Canadian Society of Internal Medicine and 130 internists from the perioperative medicine research interest group within the US based Society of General Internal Medicine. The questionnaire contained thirty research questions and respondents were asked to rate the priority of these questions for future study.

RESULTS

The research topics with the highest ratings included: the need for tight control of diabetes mellitus postoperatively and the value of starting aspirin on patients at increased risk for postoperative cardiac events. Research questions evaluating the efficacy and safety of perioperative interventions had higher ratings than questions relating to the prediction of postoperative risk. Questions relating to the yield of preoperative diagnostic tests had the lowest ratings (p < 0.001 for differences across these categories).

CONCLUSION

The results of this survey suggest that practicing general internists believe that interventions studies are a priority within perioperative medicine. These findings should help prioritize research in this emerging field.

Perioperative beta-blockers in high-risk patients

One major risk to patients in the preoperative period is that of myocardial ischemia or infarction and cardiovascular death in high-risk patients. Historically, attempts to decrease the incidence of perioperative cardiac complications have focused on preoperative evaluation and identification of patients at risk for complications with referral for additional testing and/or revascularization. Evidence suggests that the use of perioperative beta-blockers in high-risk individuals can reduce the incidence of perioperative cardiac events. The Agency for Healthcare Research and Quality has identified that the use of perioperative beta-blockers can reduce perioperative morbidity and mortality. The focus of this article is to describe the evidence supporting perioperative beta-blocker use, to discuss potential barriers to their use, and to propose a strategy to improve their use.