Review question

In people undergoing major noncardiac vascular surgery, what is the efficacy and safety of perioperative [beta]-adrenergic blockade in reducing cardiac or all-cause mortality, myocardial infarction, and other cardiovascular safety outcomes?

Nursing implications

Cardiovascular complications are associated with a high risk of morbidity and mortality in patients who undergo vascular surgery, and thus, treatments to reduce cardiac risk during vascular surgery are needed in order to treat people effectively and safely. [beta]-Adrenergic receptor blockers ([beta]-blockers) are a class of medications used in the treatment of different etiology heart diseases as well as in the prevention of cardiac complications.

It has been hypothesized that [beta]-adrenergic blockers may reduce the risk of perioperative cardiac complications through various physiological mechanisms. Therefore, a systematic review was undertaken to determine if the use of perioperative [beta]-adrenergic blockers in reducing cardiovascular morbidity and mortality in people undergoing major noncardiac vascular surgery was effective and safe.

Study Characteristics

This summary is based on a Cochrane Systematic Review of 2 double-blind randomized controlled trials, and both studies compared perioperative [beta]-adrenergic blockade (metoprolol) (301 participants) with placebo (298 participants) on cardiovascular outcomes in people undergoing major noncardiac vascular surgery.1

The primary outcomes measured on both studies were all-cause mortality, cardiovascular mortality, and 30-day postoperative nonfatal and fatal myocardial infarction. Secondary outcomes were arrhythmia requiring treatment, heart failure, vascular patency/graft occlusion, stroke, rehospitalization at 30 days and composite 30-day cardiovascular outcome, intraoperative bradycardia, and intraoperative hypotension.

The methodological quality of the 2 included studies was considered to be moderate because of differences in outcome reporting and the fact that not all the outcomes were reported in both studies.

Summary of Key Evidence

Comparison of [beta]-adrenergic blocker versus placebo or no treatment (n = 2 studies, 599 participants):

* All-cause mortality (n = 2 studies, 599 participants): no clear difference between the 2 interventions (odds ratio [OR], 0.62; 95% confidence interval [CI], 0.03-15.02)

* Cardiovascular mortality (n = 1 study, 496 participants): no clear evidence that [beta]-adrenergic blockers reduced cardiovascular mortality (OR, 0.34; 95% CI, 0.01-8.32)

* Nonfatal myocardial infarction (n = 2 studies, 599 participants): no difference was found between the 2 treatment groups (OR, 0.83; 95% CI, 0.46-1.49; P = .53)

* Arrhythmia (n = 1 study, 496 participants): there was no clear evidence that perioperative [beta]-adrenergic blockers reduced arrhythmia (OR, 0.70; 95% CI, 0.26-1.88)

* Heart failure (n = 1 study, 496 participants): there was no clear evidence to support that [beta]-adrenergic blockers reduced heart failure (OR, 1.71; 95% CI, 0.40-7.23)

* Vascular patency/graft occlusion: no studies reported on this outcome

* Stroke (n = 1 study, 103 participants): no association could be established from the single study as the CI is very wide (OR, 2.67; 95% CI, 0.11-67.08)

* Composite cardiovascular events (n = 2 studies, 599 participants): there was no statistically significant difference between [beta]-adrenergic blockers and placebo (OR, 0.87; 95% CI, 0.55-1.39; P = .57).

* Rehospitalization at 30 days (n = 1 study, 496 participants): no clear evidence was found supporting reduced rehospitalization in the [beta]-adrenergic blocker group (OR, 0.86; 95% CI, 0.48-1.52)

* Intraoperative bradycardia (n = 2 studies, 599 participants): statistically significant increase in the odds of intraoperative bradycardia in the [beta]-adrenergic blocker group compared with placebo (OR, 4.97; 95% CI, 3.22-7.65; P < .00001)

* Intraoperative hypotension (n = 2 studies, 599 participants): statistically significant increase in the odds of experiencing hypotension in the [beta]-adrenergic blocker group compared with placebo (OR, 1.84; 95% CI, 1.31-2.59; P = .0005).

Adverse events: No adverse events were reported in either trial.

Best Practice Recommendations

This meta-analysis suggests there is currently insufficient and unclear evidence whether perioperative [beta]-adrenergic blockers reduce cardiac complications in people undergoing noncardiac vascular surgery. This review indicates that [beta]-adrenergic blockers increase the risk of intraoperative bradycardia and hypotension, and therefore, the decision should be weighed against any possible benefit. More well-designed randomized controlled trials are required to investigate the effects of perioperative [beta]-adrenergic blockade in patients undergoing noncardiac vascular surgery.

Reference